SUBJECT: City of Tigard Plan Amendment
DLCD File Number 003-11
The Department of Land Conservation and Development (DLCD) received the attached notice of adoption.
Due to the size of amended material submitted, a complete copy has not been attached.  A Copy of the 
adopted plan amendment is available for review at the DLCD office in Salem and the local government 
office.  
Appeal Procedures*
DLCD ACKNOWLEDGMENT or DEADLINE TO APPEAL:  Thursday, February 21, 2013 
This amendment was submitted to DLCD for review prior to adoption  pursuant to ORS 197.830(2)(b) 
only persons who participated in the local government proceedings leading to adoption of the amendment 
are eligible to appeal this decision to the Land Use Board of Appeals (LUBA). 
If you wish to appeal, you must file a notice of intent to appeal with the Land Use Board of Appeals 
(LUBA) no later than 21 days from the date the decision was mailed to you by the local government.  If 
you have questions, check with the local government to determine the appeal deadline.  Copies of the 
notice of intent to appeal must be served upon the local government and others who received written notice
of the final decision from the local government.  The notice of intent to appeal must be served and filed in 
the form and manner prescribed by LUBA, (OAR Chapter 661, Division 10).  Please call LUBA at 
503-373-1265, if you have questions about appeal procedures.
*NOTE:     The Acknowledgment or Appeal Deadline is based upon the date the decision was mailed by local 
        government. A decision may have been mailed to you on a different date than it was mailed to 
        DLCD. As a result, your appeal deadline may be earlier than the above date specified. NO LUBA  
       Notification to the jurisdiction of an appeal by the deadline, this Plan Amendment is acknowledged.
Cc: Gary Pagenstecher, City of Tigard
Gordon Howard, DLCD Urban Planning Specialist
Anne Debbaut, DLCD Regional Representative
Amanda Punton, DLCD Natural Resources Specialist
<paa> YA
NOTICE OF ADOPTED AMENDMENT
02/05/2013
TO: Subscribers to Notice of Adopted Plan
or Land Use Regulation Amendments
FROM: Plan Amendment Program Specialist
~!2 DLCD 
NoticeofAdoption 
This Form 2 must be mailed to DLCD within 20-Working Days after the Final 
Ordinance is signed by the public Official Designated by the jurisdiction 
and all other requirements ofORS 197.615 and OAR 660-01 8-000 
-,-----------0 In person D electronic D mailed 
D 
T DEPTO E 
s FEB o 1 2013 T 
A LAND CONSERVATION M AND DEVELOPMENT p For Oflice Use On ly 
Jurisdiction: City of Tigard Local file number: CPA 2011-00004 
Date of Adoption: January 22, 2012 Date Mailed: January 31, 2012 
Was a Notice of Proposed Amendment (Form 1) mailed to DLCD? D Yes D No Date: 12/20/11 
D Comprehensive Plan Text Amendment D Comprehensive Plan Map Amendment 
C8J Land Use Regulation Amendment D Zoning Map Amendment 
D New Land Use Regulation C8J Other: "Significant Tree Groves" Overlay 
Summarize the adopted amendment. Do not use technical terms. Do not write "See Attached". 
Comprehensive Plan amendment incorporating the "Significant Tree Groves" map and Tigard Development 
Code {Title 18) amendments to Chapters 18.115, 18.120, 18.330, 18.350, 18.360, 18.370, 18.390, 18.530, 
18.610, 18.620, 18.630, 18.640, 18.715, 18.745, 18.790, and 18.798. 
Tigard Municipal Code amendments to title and chapters 1.16, 6.01 , 6.02, 7.40, 8.02 thru 8.20, 9.06, and 9.08 
are proposed in support of the Title 18 amendments. In addition, the Urban Forestry Manual was adopted under 
administrative procedures in TMC 2.04. 
Does the Adoption differ from proposal? Yes. 
For Planning Commission changes please see UFCR Volume V, page 3 
For City Council changes please see Attachment B to Ordinance 12-09 and 12-11 
For City Council changes to the Administrative Rules please see Attachment B to the Administrative Rules 
Plan Map Changed from: 
Zone Map Changed from: 
Location: 
Specify Density: Previous: 
Applicable statewide planning goals: 
to: 
to: 
New: 
Acres Involved: 
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 
~~DD~~~~~~~~~~DDDDD 
Was an Exception Adopted? D YES C8J NO 
Did DLCD receive a Notice of Proposed Amendment... 
35-days prior to first evidentiary hearing? 
If no, do the statewide planning goals apply? 
If no, did Emergency Circumstances require immediate adoption? 
cgj Yes 
DYes 
DYes 
0No 
0No 
DNo 
DLCD file No.----------
Please list all affected State or Federal Agencies, Local Governments or Special Districts: 
Metro- Land Use and Planning, Washington County Department of Land Use and Transportation, U.S. Army 
Corps ofEngineers, Oregon Department of State Lands, Oregon Department ofLand Conservation and 
Development, Oregon Department of Environmental Quality, Tualatin Valley Fire and Rescue, Tigard-Tualatin 
School District 23J, the cities of Tualatin, Lake Oswego, Beaverton, King City and Durham, Oregon 
Department of Transportation, Clean Water Services, Oregon Department ofFish and Wildlife 
Phone: (503) 718-2428 Extension: Local Contact: Marissa Daniels 
Address: 13125 SW Hall Blvd. 
City: Tigard, OR 
Fax Number: 503-718-2748 
Zip: 97224 E-mail Address: marissa@tigard-or.gov 
ADOPTION SUBMITTAL REQUIREMENTS 
This Form 2 must be received by DLCD no later than 20 working days after the ordinance has been signed by 
the public official designated by the jurisdiction to sign the approved ordinance(s) 
per ORS 197.615 and OAR Chapter 660, Division 18 
1. This Form 2 must be submitted by local jurisdictions only (not by applicant). 
2. When submitting the adopted amendment, please print a completed copy of Form 2 on light green 
paper if available. 
3. Send this Form 2 and one complete paper copy (documents and maps) of the adopted amendment to the 
address below. 
4. Submittal of this Notice of Adoption must include the final signed ordinance(s), all supporting finding(s), 
exhibit(s) and any other supplementary information (ORS 197.615 ). 
5. Deadline to appeals to LUBA is calculated twenty-one (21) days from the receipt (postmark date) by DLCD 
of the adoption (ORS 197.830 to 197.845 ). 
6. In addition to sending the Form 2 -Notice of Adoption to DLCD, please also remember to notify persons who 
participated in the local hearing and requested notice of the final decision. (ORS 197.615 ). 
7. Submit one complete paper copy via United States Postal Service, Common Carrier or Hand 
Carried to the DLCD Salem Office and stamped with the incoming date stamp. 
8. Please mail the adopted amendment packet to: 
ATTENTION: PLAN AMENDMENT SPECIALIST 
DEPARTMENT OF LAND CONSERVATION AND DEVELOPMENT 
635 CAPITOL STREET NE, SUITE 150 
SALEM, OREGON 97301-2540 
9. Need More Copies? Please print forms on 8~ -1/2xll green paper only if available. If you have any 
questions or would like assistance, please contact your DLCD regional representative or contact the DLCD 
Salem Office at (503) 373-0050 x238 or e-mail plan.amendments@state.or.us. 
http://www.oregon .gov/LCD/forms.shtml Updated December 6, 2012 
CITY OF TIGARD, OREGON 
TIGARD CITY COUNCIL 
ORDINANCE NO. 12-_0_ 
:\ N ORDIN,\ NCE TO "\DO PT DE\'LLOPI\U.:NT CODE , \l\{L·:ND~\1ENT D C \ 20 11 -00002) TO 
:\ tvll~ND CI·JAPTERS I~- 11 5, J 1-\. 120, 18.31U. 1K.350. 18.3(J0. 18.370, 18.390, J 8.6 10, J 8.620. 18.630. 18.640. 
18.7 15, 18.745, 18.775, 18.7 <)() J\ND 18.798 OF ·.n IE CCYi'vfl\·1UNITY DEVELOP.MENT CODIL 
----- -------------- - AS AM ENDED BY THE TIGARD CITY COUNCIL ON 
NOVEMBER 27, 2012. SEE EXHIBIT B ATIACHED. 
\\' HERJ :j \S, on June 3. 2008 the Tigard City Council adopted an Urban Forest section as part of rhe 
Comprehemivc Plan in order to establish broad goa ls and pobcics to guide the long-term management and 
enhancement o f the urban forest; and 
\\'!! FREAS. on "·\ugu~t 10. 201 (l the Tigard City Council readopted the t'rban Furest sec tion as part of the 
Cornprt:hensiYe Plan in order to provide mo re det::1iled findings to further support and explain tlw rationale for 
the city's urban forestry goa ls and policies; and 
WI !ERE.\ ~ , Policy 2.:2. 1 of the Tig~rd Comprehensive Plan requires the city to periodically updare policies, 
rcgulatiom and standards regarding the city's urban fores try program; and 
\X 'II l :.Rt::AS, Policy 2.::?.. 11 o f the T it,>a rd ComprehensiYC Plan requires the citY to dc,·elop and implement a 
citywide Urban Forestry Master Plan ro guide rhc upda te of the city's urban forestry program: and 
\\l!E REAS, o n Nm·ember 10. 2009. the ·rigard Ci ty Council adopted Resolution 09-69 accepting the City of 
Tigard's Urb;w Forcsu·y I\ fa ster Pl:Jn; and 
\\'I:IERl~;\S, the accepted Urban Forestry 1\Jaster Plan analyzed the past and present conditions of Tigard 's 
t' rban l:orest. was developed through a public process, ancl sets fonh a couN: of action for ·rigard 's urban 
for{'stry program through 20 J 6; and 
\\'11ERE..-\S. the Urban Forcsr.ry ;\faster Plan recommendations include updates w the city's urban fon: stry 
~tandards for development such as tn :e planting, preservation and removal requirements in Tide 18, and the 
dc,-elopment of flexible and ioccntiYe based land use regulations in Tide 18 fo r significant tree grove 
prc~e1T:llion, which re<.Juire CP :\201 1-00004 to be adop ted; and 
WI! ERE:\S, o n February ](,, 2010. th<: T'ig.ud City Council direcwd sr:1lT ro implement the CommLmity 
Development Code related rccommendaciom in the Urban Forestry l\1ast:er Plim which include update~ to the 
city's urban forestry ~ ramhrds for development such as tree planting, pre~ervation and removal ret1nirements in 
·ritle 18. and the ckn:loprnent of tlex.ihle and incentive based land usc regulations in Title l 8 for ~ignificam tree 
grove prcsen·ation; and 
\VI U:lU~:\S. a public im·oh·ement plan was adopted by the ciry's Committee for Citizen Involvement in 2010 
and implem ented during the course of the l ' rban Forestry Code Revisio ns project to guide city staff and 
decision makers; and 
\'\.'I TERL~:\S, a council appointed Citizen .-\dvisory Committee charged with ach-isin)!; project stall during rhc 
U rban Forest:!)' Code Rc, ·isio ns project met ll times between J unc 20 10 and September::?.() I 1; and 
ORDIN _·\ NCL: No. 12- OCj 
Page 1 of 4 
\\ '1 JF.H E :\S, the Ci tizen , \J,"i~"ry C:omnJ.ittcc reached comen~us un the Jlexiblc and inccntiH· based land usc 
rcgularions for tree grove prcsc:rvat.iun in :-;cction ·1 R.7()(l.(J5UJ) through a set of ''tree gn>n· prcsctYat ion 
incenti,·cs guiding principles" ; and 
\\ ' I IEJU·: .•\S, the Citi;..:cn .\d,·isory Committee reached con~cmus nn the nthcr l:Jnd usc rcgui~Hion s in Tide 18 
thar support general urban forc~ t enhancement actjvitics such as tree plant'ing and presuTat1on when not 
<1ssoci;1tcd with sig nificant ltTt: gron:s through a set of ''urban forestry smndanb for de,·clopnwnt guiding 
principle/' ; and 
WI II ~RE:\S, a 'I ·cchnical :\tkisory Comrnittet: co mpti scd nf citY staff and agency repn:sm1:11in:s wa s 
concwn:ntly com-cm:d tu advise project staff on technical aspects dming the Urlnn FurcstlT Code Rc,"isi on~ 
project met 14 times bct\vcen June 2010 and November 2011: and 
\\ '1 l l·J\F,\S, the Technical :\dYisory Committee reached con~emus on the technical feasibility of the flexible 
and incentin· ba~cd land usc regulation~ fur tree grm·c prescrYation tn Section I H.790.050.D: and 
\\'1 lLRL~AS, the Technical .\(h-isory C(lrnmittce re:1chcd con,;m, u,; on the technical fea sibility of the other land 
use regulations in Title 1 H that support general urb;ln forest enhancement acti,"ities ~uch a~ rree planring and 
preservation when no t as~(lciatcd with significant tree groves: and 
\\ 'lH-:IZb:.\S, the d<s elo pmcnt of land usc rcgulacions in Title 18 that support gnwral urb:u1 t(JtTSt 
enhancement acti,•icics ~uch as tree planting and prcscrY:.Jti on ,,·hen nor associarcd with sig nificant tree grm·L·s. io 
not required tu comply with Statewide Planning Coal 5 Rule retjuiremenrs because rhcsc <1CtiYitie;-; do not crearc 
or amend a resource li~t ur land usc regulation adopted in (Jrdcr to protect a Coal 5 resource; ami 
\\ 'lllJU~,\S, rhc: prncc~~ f(>r adopting land u~t· rcgulati<>m fo r the pre~ervat1nn uf naruraJ rc ,ource~. including 
the flexible :1nd incentin· b ;1sed bnd use regul ~ tions fo r tree gro\"C prc~etTauon in Section lH.7<Jfl.05(l.D, mu~t 
comply with Statewide Planning Coal S Rule ret]uiremult~; and 
\\"I IERL::\S, pro jec t. staff and consultants drafted flexible and incentive based land usc regulalions for tree 
grove prcsernnion in Section 1l:P<J0.050.D including allowed reduction in minimum densitY, density tG\11sfcr, 
increased building height, reduced sctbacb, adjusm1cnrs to Urban h)l'cHry Plan rec1uircmcnrs and adjustments 
ro street and utility standard~ to facilitate tbc preservation oi ' ignificant tree grove~ as pan of the land 
developmen t prucc~~; and 
\\ 'I II J\J ~ . \S. project :; r,lfJ dr~ ftcd o ther land usc reguhtic'ns in Title lR that suppurt gencr:ll urban fore st 
enhancement ;'lct:i, · itie~ such as tree planting ;1nd prese rYati<>n when not a:';ociated \\i th significant tree grm ·e~, 
the main purpose of which :tre to create equitable, ach.ic\'ablc and ~cientifie<tlly sc >und JTt]U.ircments for all maj u r 
dcvdoprncnt:s to plant or presern: a certain amount of tree Gtnopy to support city,vide tree c:m• >py coYer goals 
rcconunended in the t : rban l ·orcstn- l\.faster Pbn a ~ part of the land den:·lopmcnt: process: and 
\\'ll FlU~ ."\S. o n January 1.), 201:2, prior ro the lcgisbnin~ adoption phase of the U rban Forestry Code Revis ions 
project, 14,225 public hearing no tices were sent tu all Tiga rd property owners consistent with I\ kasun: 5(, 
re<.Juir('tncnts as further described in the findings of the naff report beginning on page 419 of LJrban J."orcstry 
Code R<'Visions \' olume ll; and 
\\ 'IIEREAS, project staff and consultants held ;J cit~·widc open house on December H. 2011; and 
\VI IERIL \ S, the public re ~po1!:'e ar the city'\\iJc o1x·n house on December H. :2011 and after the l\kasure 56 
notice" were senr o n Janwtl)' l.l, 2012, \Vas generally suppnnin· o f the tkxihle and .inccntiYc ba sed land U!'t: 
ORDI~ :\NCL No. 1:2- 0 Cj 
Page 2 of 4 
regul;Jtions f()J· tree grove preservation in Section 1 K.7CJn.05ll.D and rhe other land usc reg1il:nions in Title 1 K 
thM support general urban t(H·e~r enhancement actiYitie!" such ;ts tree planting ;111d presctTation when not 
assuciMed with significant tree grm·es; and 
\Xl HJ •J{F;\S , the Tigard Pl:-~nning Commission rcTiewed at one workshop and four public hearings between 
.Janu:try 2012 and l\:Jay 2012 the flexible and incentive based land usc n :gularions for tree grow pre~ervation in 
Section 18.790.050.1) and the other land usc regulat:iom in Title 18 that support general urban forest 
enhancement activitie~ such as tree planting and preservation when not associated with sit,>tlificant tree gnwcs; 
and 
\\ ' IIERE:.'\S, the Tiga rd Planning Commission supported the amendment of land use regulations in Title lK; 
and 
\X 'IlERE:\S, rhe Tigard l'bnning Commission t(•cornmended four non substantive text amendments for 
correction and clarification pmvoscs: and 
\\-'ll ERF.AS, the Tig~1rd Planning Commission recommended lhn.:e subs r:~ntivc text amendments to incrt·asc 
flexibility in meeting Title 1 H requirements which include lowering the per lot minimum tree canopy 
requirement in lower dl>nsity residential districts, dirninating the per lot minimum tree c<~nopy requirement in 
higher density residential and non residentia.l districts and allowing landscape architects, in additjon t:o arborists, 
to dt:vdop u.rban forestry plans; and 
\\'] l EJU~·\S, on l\1a~· 7, 2012 the Tigard Planning Commission m:~de a unanimous recommendation to the City 
Council ior approYal of DC:\ 201 J -00002 as <~mended by motion and unanimous Yote; and 
\\ '] ll :J\EAS, as desCJibed in the fin din~ of rhc s t <~ ff rcporr beginning on page 419 of Urban Forestry Code 
Revisions Vohum· ll , the Planning Commi~sion found the city complied with Statewide Planning Goal 5 Ruk 
requirement~ throughout the development of Hexible and incenti1·e based bnd usc regulations for tree grove 
preservation in Section 18.790.USO.D, and complied with all applicable bnd u;;e planning requirement~ when 
den~loping land u~e regulations in Tide 18 that: support: general urban forest: enhancement acrivit:ies such ll& tree 
planting and prese rvatjon when not: a~sociatcd with &igniticant tree groves; and 
\\'1 IERl~:,\S , on the foUO\\.~ng dates in 2012: Jul y 2-1, r\ ugusc 14, September 1 1, October 23, Non:mber 13, 
and Nrwember 27, the ' I'if:,>ard City Counc.il held a public bea ting to consider the Commission's 
recommendation on D C\ 2011 -00002: and 
WI IE.:I\E, \S, 'I'if:,>a rJ City Council finds it necessary to dcby impkmcnration of the L'rban Forestry Code 
Re,' isions, which include DC:\ 2011-00(!02, until i\'farch 1, 2013, ro ensure an orderly administrative tl'ansition 
to tht: new urban forcst:r~· regulations; and 
\X'llERE.'\S sufficient time is needed i~> r the City 1\Janager to administrati1'dy adopt the Urban Forestry 
1\hnuaJ pursuam to Chapter 2.11-UJS0-07(1 (.\dministrarivc .Rulcmaking) and Section 8.02.030 (Administrative 
Rule~ U rban Forestry Manual) prior to the ;~doprion of Title 18 amendments \Vhicb r<:tjui.re the L'rban 
Fore~tf}' Manual for implt:rnentation. 
\\TlERI~:.-\S, Council's decision to :1dopt DC\. 201 J -011ll02 is bast~d on the findings and condu,ions found in 
the City of Tigtlrd st:1ff report dated Nowmbcr 20, 2012, and the associated n ·c<.ml, which arc incoq>or<ltcd 
ht·n:in bY reference and are comained in land-use file DCr\ 2011 -00002. 
NO\\' , Tf-·ll]{J·:FORI:, 'l'l U:: crry OF TIG,\RD ORDAINS AS FOLLO\\.S: 
ORDJNi\NCF No. 12-QCf 
Page .1 of 4 
SJ·:C J'!Ol' 1: 
Sl::CT10N 2: 
SI·:Cl'J< )N 1 
SLCT10N :t 
P. \SSED: 
,\PPR0\'.1 ~D: 
Tiga rd Dt·n :lupmcnl Code (Title I H) i~ amended to include new text :mJ In n:~cinJ existing 
text as ~ hU\\11 in "EXHIBIT A - on odd numbered pages 5 throug h 183 of U rban 
Forestry Code Revisions Volume II ". 
Thi ~ ordinance ~ h:1 ll be effective \f:uch I, 2013. 
Council adopts the tindings recommended by rhe Pbnning Commi ~s inn as described in the 
findillgs uf the ~ta ff report d;:t ted Non :mbcr 20, 2012. 
Council further adopts the commcntarv in F.xhibit :\ (on <.:Yen nurnbered pages c\ through 
I t-\2) a ~ addicionallegisJat:ivc in rent. fur the corre~pomling codt~ amendments . 
. , , ._..,.. ,} - · , l n!l"c of a l C:uuncil members present a ftcr bcillg read by llumbcr 
'!:-daY o · .,.~J.;;>~t~t_... • 2012. 
?lj:;t.1.)/I,.V~.-{ 
·~- ~ J 
n, T•gml c;~ council th,,.2LJ"~Let 
Craig Dirk~cn , ?\byor 
. \ ppr~)\_:~~ ... : .. \..s.: .. .... ' .. :.< ...  ~. f ....< .. J ... n ... 1i£1 ..:. . . ... .. · -- 1 .r;rr:--:-7 · / {~·/-;;:·-·--:y~;. ------ - l 
Ci{,· At to nJe/ 
;t/J7 /t2 
D ate r 7 
()JUJIN.\NC t·: No. 12-Q q 
Page 4 of t 
I 
To: 
From: 
Re: 
D ate: 
City of Tigard 
Memorandum 
Tigard City Council 
0.1arissa D aniels, .-\ ssociate Planner 
Urban r•orcsr.ry Code H.evisions 
Non~mber 27, 20 12 
Exhibit 8 Ordinance Nos. 12-09 
and 12-11 
On 1'\ovembcr ?.7, 2012 Council is scheduled to continue the Urban Fores try Code Revisions 
public hearing. The purpose of rhe meeting is to receive a brief staff report, receive public 
testimony and consider amendments ro Planning Commission\ recommendation. 
Council Amendments for Consideration 
~taft has prepared se,·eral amendments to Planning Commission's recommended dra ft based on 
Council direction on October 23 ilnd November 13, 2012. 
Addresses 
Amendn1ent Policy Issue Brief Descri£tion 
1 3 Differenciates between residential and non residentiill maintenance 
requirements for trees planted with de,·clopmenr. 
··-
'I 4 Removes tree removal permit requirements for single f~11nily 
-
residential developments. 
-------· 
On 11/27/2012, .., 5 Clarifies that hazard aces are rec1uired to be removed only in ,.) City Council 
approved response to verified complaints. 
amendments 1, 
Enhances the purpose statement in Chapter 18.790 to draw a clear 2. 3, 4 and 6. 4 7 
Amendment 5 
was not link between the details in the Urban Forestry Manual and the 
approved. 
overall purpose of the development code revisions . 
- -·- -·· § ::;. Adtb the e~~:ftn~y reEJtliretneM~• te the eede t:~~ draw a elearer lifll<:: 
bet\veen rhe detaib in the Urhan F~H-e!ltJcf Ml'tnt!l'tl and the o\·erRil 
. C .1. • .1 .. • 1 .J . . . 
-
. ' " '" 
.. " .. 
6 8 Reduces dcn~lopmenr cosrs for Minor Land Partitions by not 
requiring an arborist or l and~cape architect for partition projects 
that can meet the requirements by planting street rrecs in o pen soil 
volumes o nly. 
At the November 13 meeting, Council asked smff if there arc any issues associared with no t 
requiring arborists/landscape architects for ivlinor Land Partition projects that can meet the tree 
umopy HXJUirc.:mcnts by planring street trees o nly (.\rnendmenr (J , Policy I sstte ~) - In deciding 
\vherher to adopt this amcndrm:nt, s taff offers the following considerations: 
1. Reverse Incentive -This amendment could create a reverse incentive where a property 
owner might remo\·e mature tree~ and plant onh· street rreef' ro avoid costs associated 
with hiring an a rbnri~t / landf'cape architect. 
') E quity - In de veloping the Urban l ;orc~trv Code Revi ::: iom, one of the main community 
goab wa~ to address r he e(1uiry issue in the exi sting code rhat places more financial 
burdens on p roperty uwner~ with matu re tree~ . The ca nopy approach addre~ses rhi~ is~ue 
by applving the same requirements regardle ss of the amounr of existing trees. This 
amendmen t could result in an equity issue by CM' tTtpting owners without tree ~ from 
hiring arbori~ts / bndscapc architects, \\·bile placing greater lTLtuircmcn t:- on owner~ that 
choo~e to prese n ·e mature trees with devcloprnenr. 
3. Adjacent trees - ~-linor L,and Partitions inYolve rhe creation of two or three nc\\' lnrs in 
l~ xisting rc~idcnri a l neighborhoods (aka infiU development). Often one of the greatest 
points of conflict: with infill JcYclopnwnr i~ the potential development impacts on tree :-> 
rhar arc on an adjacent propcrry bur ncar the property line. Involving arborists / landscape 
architect~ in the deYclopn1erH of f\tinor Land Partition s help~ ensure trees adjacent ro the 
sire arc protected wirh accepted mcthuds such a~ tree protection fencing dur1ng 
development. If profc ssion :1 l~ arc nm required, there i:.: less ccrtainry for neighbors that 
their trees will be adeLJUatcly protected. 
l\lorc .information about each o f the amendment~, including the affected code sections and 
specific amendments arc included on page 3. Council wi ll ha"c the opporttJniry to accept, reject. 
or modifv these amendments o n Novemlx·r 27. 
H ousekeeping Amendments for Consideration 
In additjon to Council 's amcndrncnts, qaff is also recommending a se t of housekeeping 
amendments to the code. 'fhe~e it"em~ arc insubstantia l to the code, and arc described in rno.rT 
detail on page 13. For cxarnplc, Amc.:ndmenrs ~ and 9 correct cross references internal ro the 
code. 
2 
Amendment 1 approved by council on 11/27/2012. Amendment 1 is not part 
of an ordinance nor is It to be codified. This amendment is applicable to 
Volume IV- Urban Forestrv Manual I Administrative Rules\ 
Amendments to the Urba n Forestry Code Revisions Based on Council Direction 
Amendment l (Policy Issue 3): Differentiate between residential and non residential 
requirements for the m aintenance of trees planted with development. Residential trees 
should have a maintenance period of two years or until a house is sold. Non residential trees 
should have a on_~~year maintenance period. 
Code/Manu al Section: Urban Forestry ?vfanual Section 11, Part 2 (Urban F•'orcstry P lan 
I mplemcnrarion Standards- Tree Establishment Requirements:) 
.:\. Prior to any ground disturbance work, the applicant shall provide a tree 
establishment bond for all trees ro be planted per the approved urban forestry plan. 
The total bond amount~ 
1. E!:u:.Jillb.d.irisionsaud minorJan<;.LJ#.\t:titiP.n!'ishall be ecp.1ivalent to the city's average 
co~t to plant and maintain a tree per the applicable standards in the Urban 
Forestry l\ianual for a period of two year~ after planting multjplied by the total 
number of trees to be planted and maintained;,.and 
2. for all othc.rJam:luse review t\;pc;~ _shall it.~ -~SJuivalenuothecity~s_ ayerage cost tp 
phl!1L\lPQ maintain. a tree per the appjicab.lc .stand3rgs _in_rhe_UrhanEore.sr.ry 
ivfanualj:_gr a p_~tipJ pf.on.e_yc.ar._after plaotior m ultiplieq b_y .the tm;;l)JlMt.nber of 
tte..c.8 .. to .. b.c ... plantcd aod,.,tpainJai.ucJ1, 
B. l ''ollowing final buikling inspection or upon acceptance by the city manager or 
de~igoee when there is no final building inspection, d1e tree e~tablishment period 
shall immediately begin and continue~ for a pe.riod of two years. 
c 
D. 
r·:. 
F. 
(·~ J. 
1. 111 . .s.ubdivisiOJ1§.. '111Q,..p\lliition.s.Jw:....<Lp.c.riu.(toLn.vo years or un_til_.sus:lU.il::O!,': _;a_s_ C<)ch 
lot..is__so1d~ and 
2. In all mhcr land L_!S~ reYiew __ rrpes.Jm: a period of one year. 
\Vhcn the bnd usc review type \vi.ll result in the division of land .into multiple lots or 
tracts, there shall be a separate tree establishment period for each resulting lot or 
tract where trees are shown to be planted in the approved urban forestry plan. 
F'ollowing the two yeaf applicable tree establishment period for each lot or tract, the 
bond shall be correspondingly reduced based on tree survival following a site 
inspection, documentation of successful tree establishment and / or replacement 
according to item~ e E an<;U,~· below, and receipt by the city manager or designee of 
wri tten verification of .findings and a signature of approval by the project arbo.rist. 
For planted open grown trees, successful establishment shall be considered 80 
percent :::utTival of the open grown trees p lanted on the lot or u:act, and replacement 
of 100 percent of rhe remaining open gro"vn n·ees planted on the lot or tract that Jid 
not: survive. 
For planted stand grown trees, successful establishment shall be considered ~urvival 
of at least 80 percent of the original stand grown trees planted on the lot or tract. 
1 f successful establishment for open grown trees is less than 80 percent for any lot or 
tract, the h\'O year ~k-1\JJJe. . .trec establishment period shall reset for that lot or u:act 
and the establishment process for open grown trees described in part 2.B-F above 
shall be repeated until the successful establishment requirement for open gro\vn trees 
3 
Amendments to the Urban Forestry Code Revisions Based on Council Direction 
,----··------- --·········· ············---- ···········- ·······--
ts met. 
H. If successfu l estabhshment for sranJ grown trees is less than H() percent for any lot 
or tract, the two year flJ:mJis;ahl!..:._ trcc cstablishrnent period shall reset for that lot or 
tract and the establi~hme nt process for stand grown trees described in Pan 2.B-F 
aboYe shall be repeated until the successful establishrnent requjrement for stand 
g_rown trees i~ met. 
'· 
Note: Exhibits A and Btu the Rcsolurion revising The [\Jaster Fees and Charges Schedule 
is amended as follows to reflect changre~ in rhe methodolo<rY for calculating tree bi (... 
establishment bonds: 
I ~xhibir :\ - Legisbti,·e Intent for Urban Fon:stry h·c~ 
Master Fees and Charges Resolu tion was not 
considered/adopted by the council on 
11 /27/2012 
'free Establishment Bond (Plapting and 2 Ye,u:; nf L:arly .Estabhshment) 
S489 per 1.5 inch caliper open grown tree fo_r._s.uhdi:risions .ansJmjgpr hod partitiuns"' 
~;ll,J£~.inc.h caliper u_pm g;ro,wn_J_t;s;g (or la nc.l.J.Is.c_.rc.vi<..~\VJl:p c s o tb e [ thi.J.:H.:~l:.l h divis iill1s 
a.nd.JJ1inorJan1lg!1rtiti o ns_:_~_ 
$367 per 0.5 inch caliper sta nd grown tree (Q1:"$\lblriiris.iilllS_alldlu.inudan~!-Q!l!=rir!nn~· ".!, 
S35Jpcr.IJ.5inch_calipcr stap~;,Lgrown tr.c.c Jw:J.an.d usc review t:):p_r~J?tbsr rhan..s.J.llxiivisi.urui 
.!Ult.l t_xtiwn ! ;w.,d_p;u:titions.:::_-+- "'-~' 
"The Tree Fstablishmcnt Bond for the p lanting and maintenance of a 1.5 inch caliper tree t~)l· 
the required two years ilLSl.lhili:Usillos and minorJ;m<.,tPil.Pitions is based on a fimnula that 
cotTlbincs 5(1';', of the published PN \X!lS.\ wholesale median tree cost estimate ro purchase and 
install a 3 inch diameter tree, wirh the a\T tage historical cost for City of Tigard staff to perform 
two years of maintenance on a 1.5 inch caliper tree: . 
~be .l.rcc l•: stabJis!1.m&;nt 11oru:.Uor_rhe plantingawJJna.~-~Is:nanc_~.:_uf.aLSinch._u:Uip!.:Ltrce fgr 
the requircd.une.}:!dlr in land USCJ!;'Yir.w _t\'pcs__orhcr rhan subgi\:isiuu;;and minur.Jarulp..artitium 
is based on afm1Il.ul.atha.t combhK§5.Q_~/o pf t.hc..p:ubJi.shed PN\'SJ$\.2Yhul~;;s!lk-.U1e.gi:lu m:c 
~: <) sr \' s tima ts:.. tUP\JJS.: b asc and..in.stalLa. 3 ilKb__gj_;Jnl~t.}:r trec,. .. \\it:h..tllf' ay erage hit'Jm:ib.alrP§L fl:.l.t 
.city.oJ Tigard staffmp.er fonn qn_~_ygaLO.Lrnain.tc.nanc.c.. < m a_l. 5_in c h caliper n-ee.. 
t*,.+:The Tree J ·:~ tabli shment Bond fur the planting and maintenance uf a tree two (cct in height 
or one g:dlon container size (estimated 0.5 inch caliper) fuLtlli:...I:CJ.}.uired two },;.<::a!:~jn 
.s.J..Ihdi~:.isio.ns. and minqrlu!l~toanitiw1:i is based on a formula that combines l 6.6(~1o of the 
published PN\X!I~1\ cost es timate to purchase and install a 3 inch caliper nee, with the a\-cragc 
historical cos t for City of 'l'igard sta tl to pcrfom1 two years of maintenance on a 0.5 inch caliper 
tree. 
-~~-~-~Tb_c.:_J 'n;s: l ~s.t.abli . shmcnr Bon.gfqt_ th· · . .. , [\\'oJcctlnhcio 
·1 
Amendments to the Urban Forestry Code Revisions Based on Council Direction 
Q.U:mc.gail.illLCootaincr size (estirn~U99 Q,~ iQ,QJ."Q~.r,)JqrJIJ.t:;JGS}Yi.r~~,Lqnc vcarin.laruius.c. 
J:C,.UcW ... ty.-ncs othcc~: tba.n~.ubdi.ri.siomLand.minor;Jg,pg pa:rtiti0.11s..is ba§G.QPO aJmJ.Ilk 
comlJ.in.es.16.6~~IoLthc _ptJblished PNWI.S;\ coste.s.timatc.tQ.P±Jrcbase .. and_insrnll a ___ 3_inc:h 
hfllipc.r. rre.£.,~tl,u:b~J.1X£J..~chistoric.al.J.:.o.st fi >rCity_.Qf.Iig<l.td ... s.tafftopc.t.(onn __ onc.vc.ar ... of 
maintenance onaJ2.5 inch caliper; ~K~Ge 
Exhi bit B - :\mended 1\bsteT Fees and Charge!' Schedule 
Cornmunity DeYclopmcnt - Miscellaneous Dc,·elopmeot 
UrbatJ Forcs tt~· 
Tree Establishment Bond (Planting & 2 Year Maintenance .Ea.rlv r:s rablisbrnGJU) 
1.5" Caliper Street or Open S489 per rxee 3/ 1/ 2013 
Grown Tree in SpbQi,~isions 
pr0·finor.LJD}i e.amtiSHJ§ 
1 5" ('' , 1' ~ ·- f'\ ....~'l lper Sttc.cto..A.._\.,LQ.,:n 
Gn?lY.n.J::rer;jn Laru.LUse 
Rc.\i.c\v1\~I2-Gii .QDJ~LJh~.!1 
StJb9i¥isiQcl1§ . .or ... Minor,.L<ill.d 
J?grtiti9n~ 
2' in H eigh t or 1 Gallon 
Container J\i.inirnum Stand 
Grown Tree inS.ubdivi§iPnS 
o_r_J\JinmJ,au.d.P.arti.ti.u.ns 
2'in.Heig.b.t .r>.LlJiallon 
,Comaine.r.N..lin.imum St.flfJQ 
GtQ}Y..t.lTreein Land~ 
Rev:icw T~'pt.s_ o_therthan 
...... - ............. ...................... .. s::_, .. ,,_,,_, ....... . 
S.ub.di.Yisioq~ or_JYlinnrJ/~.nd 
£ar..titiQ~ 
S44l._RC.LlJ:C.£; JLL(2Ql} 
S%7 per rrcc .1 / 1/ 20'13 
~-trG£ 311120n 
······- ··········-·····-··--
_ ________ ....................................... . 
5 
Amendment No. 2 approved by council on 
11/27/2012- Ordinance No. 12-11 
Amendments to the Urban Forestry Code Revisions Based on Council Direction 
Amendment 2 (Policy Issue 4): Do not require rrcc removal permits for single family 
residential developments. Applies to Ordinance No. 12·11 
Code/Manual Section: Tigard i\Junicipal Code Chapter 8.12 (rrecs that were R<:L]Uircd 
with D c\·clopmenr) 
R-12.01 () Purpose 
T'he purpose uf this chapter is to establish stnndards and procedures for the 
maintenance, removal and replacement of rrccs thar were required with highdcJ~ 
r.t:.si.d.cn.ria.Land OQJJJJ~$.isiqJti.i.lJ development ro maintain their cn\·ironrncnral, aesthetic, social 
and economic benefits after the dl'vclo prncnt process is complcre. 
8.12.020 Ccncral Provisions 
.\ . The pro-visions of this c hapter do nor npply unlos there i~· 8uo~•tanrial 
e"<·idcnce thftt one of the follo\Yint:; .litut~riom exist ~<: to.resj}lcmial d~..::.:dopmcnr:; in tbrB:J. 
1\..:l,_R:.l.S. R -4. S, R :_I.,_ a U\r.lJ\.J_2_ dis rxic.t:i, 
It ................ Jl1c pro\·isiQ.D.::tDfJbi;;J,;baw;crdoapp.ly .. \Vht:n there i:; stJ I>stanti~knc.c.that 
Qll~ s>f (]l_~ (ollnwiug~itu.arions exists: 
1. .Excc.p.tJor those cl£.r~l®mcnts lis.ted in t$.12.020.:\ abm~s;. ;Errecs were 
planted or pn:~ern~d under a rcyuircmcnt found in Title 18 o r found in a land use permit: 
nnd 
2. Trees.~. required as replacements for tn:c:; originall~ · rn1uircd under 
8.12.020.-All. 1 abo\'C. 
#C. The city manager or dc signl' l' shall uti!i;;.e all aYai lnblc land usc permit records 
and data when determining \vherhcr a tree is subject to the provisions of this chapter. 
Note: The corresponding commentary for the code amendments is amended as follows to 
provide a record of lcgislatin intent: 
Chapter 8:12 TREES Tl L\T WEl\.E REQUIRED WITll DE\' ELOP1\1 l ~NT 
Chapter 8.12 establishes rhe framework for pcrrnining decisions for trees that were required 
to be planted or prc:;c:n·cd by a land usc permit for higbdmsirv rcs.idc.nrial and non 
r~tiaLd.c~..:.clo~whcn rhc rcmonl is no t as:;oci:ncd with an actjyc land usc pcnnit. 
The intent of the legislat:.i,·c amendments in Chapter f->.12 is to supersede the planting and 
prcserYation rccp.:tircrncrus for trees that Wl'te required by prior land use decision:'. This 
includes trees rhat arc recorded as presen·cd on propcnv deeds as a result of past land usc 
.. ·-------··-····-
G 
Amendments to the Urban Forestry Code Revisions Based on Council Direction 
decisions. !Towen:r, for these deed restricted trees, applicants (and not the city) will be 
solely responsible for idcntif~·ing and removing any applicable deed restrictions. The city will 
provide any signatures necessary ro facilitate the rcmoyaJ of deed rcstricrjons for trees 
permitted for removal by decisions pursuant to Chapter 8.12. 
The rea.son.Jor_il.U~J.!itiD.gpc±tJUt§for ttees .r~.:m1i red J.Yithd~dgpm~n.LinJo.\v. ... and 
.mr~J.iJ .. tXP .... dGJl~i~tGAi.~k!ltiaLdev.clopJnt:JJ,_t is be&ill,1S~J:llo~J~\YJ.Kt$~thc.s.e ... p.topc.ni&~.~--- !1I~.m-l.ih .c!y, 
m.mai11tain.<J t1q pre_~g_rre ... tn;<,;~_juJl:l~~~Joc.ation.s ... regar"dks~ ... oLc.D.qc t;<,;_q,t,tin::_nJe11t.S ..... :1:hc 
Q!~~\lillSW.D.~-~~='l1l~JJ; .... O\Vncrs dccigc_ tJ.1 .... t~'Il:!PYG . bG<.iliJJ.J~Jt~g-~---·r<,;qpire!..L\vith. dc:D::~1.1!:.J.1t-'l1;~ 
~'m·l'"cJe.d r~c~_.m~gl.i~~i!J.I .r ... :.\YllGP ~~ill.PP~arc.d ... wjrh,:!.'jgn_!: <.:i' .~--- <l .Y<;I<~.Q~~,t, 
U9~Y(;,'.X(;,'.J •... AJj.:,ljJ:L1P~Alill1ttono.tc ... thar._rJJ~~-P~'IDJit.m&hq_~til;cmCJlts.Jor ... S.trccLal1_t_l 0:1gdian ... ]'n:;_~,& 
(~JhlQ . tet8.08) •.. 1'rcc_~J- .. ~<;n __ ~j_Jj_~land~ .... (.8 ... 10) •. :J.·.~:~~§ _that .. \Y.C:ft .... PJa.n£cd.JJs.ing ... tbc.Urhan 
l·:qx<;.»JJ;~:J;J,lJJd c(_&,.cl4) ... and ... llerit~ 'l ~cee~_(S,JJ),)o~o ukL.continue .... to .. rumlr ... ~'.:Y.G.n ... in .... l51)cY_.and 
UJGW~UJlJJGn.,itY=t<;.~i,<,h;n_tial ... dcvdopmemJ n a_d.\:liJiQJJ...,iJJilgt1itlc.antttee.J?;,r<)\'5::.S. .. m:gl2X~A~IYcd 
inl9~~fLQ.&-i nJ<;d_iPmJ;l~.;n.siiY ... ,t::~§jt,@Jial .... d.c.:velopmc.ru,_ili~: -~'Uit}J;:!}P1~Y:e.c ... gro...:e .... ptc.s..c C\'il£iPJl 
J~~El\UtG!JJq;~r.s in ... s.cc.tion .. 'I 8._?9Q.(l5Q,12 ... \Y,ill,I}~LfctPW~ 
8.12.01 (J Purpose 
The purpose statement explains rhat rhc chapter establishes standards and procedures fo r 
trees rhat were required with l~<lem;itr tf$!drxuial anJ:i,n,Qn££~19cntial dc,' clopmcnt to 
maintain their benefits after the de,·elopmcnt process i$ complete. 
8.12.0.20 General Prm·isions 
The provisions of Chapter R.12 apply ro trees required ro be planted or pn·servcd inJ±igh 
dcnsityrc~identi!lL!tndJWO residentiaLdevcJomnentby a land use permit and trees that arc 
required as replacements for said trees. 
l:h~pJ:<:>Yisionso.tC:b..:i!P .Kt.. .. 8,.1.2 ... doncn ... aJmlx. t<l t·£ .. :?.i9.b.o.t.!al ... dcvclup.mc.ntun,,tb~_ R.J, _ _B, _~_4.J.\.:: 
3 .. 5 •... R.::4 .... 5. •... R:::.7 •.. a 11cj JS._-l_2mdit>lt.i .~_rs .. siJJ~~J;he.s.e. .... are .... tb.e ... I£rilnJJ,.t:XI.P.~.:i!liQ .O.S __ oLs.i1lg;lc .... family 
I~~~~1~gt> ..... J.:b.£JJroyisiq_ns ~ncd.f)·_ ':re. sid.entiaLdc\:elop.menJ.t>. ' ' m~o_.~5J1Qt to __ cx.empt_non 
re. .s.id~'.ntialde,~<,;l@plc.nt.s .... s.uch ... a.s. __ schJI.~.{)~ ... i11 ... rrs.id~'ll.tifl.ldis.t.ricts.Jrommth.~.:_r.c_qttiremclllS... 
8.12.030 tv[aintenancc of Trees That Were Required With D evelopment 
Trees r.hat \Verc required to be planted or preserved inhigb_d~:nsiJy_ n::sidGt.ltifrLa.n~L~on 
Ie.$identigld£YClPP.!Il~J1Lby a land usc permit are requireJ to be maintained per tree care 
industry standards. 
I R: 12.040 Removal of:!_~£~~s ·n,at Were Rcyuircd \X~i_t.l?. _!?_c:_vcl~ment _____ _ _j 
7 
Amendments to the Urban Forestry Code Revisions Based on Co unci l Direction 
·------------- -------·-·----··-····· 
P<:rmi ts obtained through the City I\ lanngcr Decisio n 1\ lnking P rocedures o r the City Boa rd ··1 
or Committee Dccisirm Making Procedures arc rCLJUircd to remove trees required to be i 
I 
planted <Jr prcse.n ·cd ill,bigb,, \J,cp,~ityJ;£sidrntiaLandno!ltCsidcntialdc\:c1£JJ2li1GJJLb)· a land I' 
usc permlt. 
----------------------------··-- --· ----·--·····--·····--···--·····--··----- ------------- -------------' 
B 
Amendment No. 3 approved by council on 
11/27/2012- Ordinance No. 12-11 
Amendments to the Urban Forestry Code Revisions Based on Council Direction 
Amendment 3 (Policy Issue 5): Clarify that haza:rd trees ate requited ro be removed only 
in response to verified complaints. 
Code / M anual Section: Tigard I'vfunicipal Code Section 8.06.020 (Hazard Trees Prohibited) 
;\. !-Iazard rrces thata.re...v..crificd rhro~Jg}U_be Hazard_]'ree E!::1tluarion_nnd 
Abatcm.cntP....tllcedure in SecriQn 1 of rhe Urb.an..l~:o.restrv ~lanual arc prohibited within the 
City of 'I'igard . 
B. /\ny hazard tree owner or responsible parry i~l{;JltiO_c~,-1 thtr.LUgh_thcHaz.a.td 
Tr.c.c_Eyalua rio o and AhatgmhnJJ~n~c~.urc._in_Scc_rion l oLthc"J J rban _F<u:t~Jryl\:lii!!JY:aJ _sha II 
be required ro complete hazard tree abatement. 
C. I''ailure of a hazard tTee mvner or responsible party idenrified_tbrough the 
l-lah.llhd-Irel:J2Y_alu.arian_and.:\.ha.tc .. menr Procedure in Section 1 oLth.c Urban Forestry 
Nao_ual to complete hazard tree abatement is a nuisance under Chapter (1.()2 and subject to 
penalties under Chapter 1.16. 
N ote: The corresponding commentary for the code amendments is arnended as follows to 
provide a record of legislaciYe intent: 
Chapter 8.06 1--IA/.I\RD TREE~ 
·rhe hazard u~ees chapter creates a framework for addressing hazard trees. 
'J 'he guiding principles for Hnzard Trees are in Volume f Y. of the legislati,·e adoption 
package for the Urban Forestry Code Revisions. These guiding principles represent the 
consensus view of the citizen advisory committee that advised staff on rhc Urban Forcsfl)' 
Code R.cvisions. 
8.06.020 General Provisions 
Hazard trees (defined in Chapter 8.02) ~e__y_erifiedthrough the Ha?:ard 'T'rec Evalua.tiuu 
€Jpg _ _;)batc_m_~or..Pn&<;;ed:nr.ejll.Se,cti.o.n. _iofthe Url_nn Forestq..l.YL'Umal arc prohibited in 
Tigard. 'T'he reason for specifying tht.~l_tbs;;prnbibirian_applies only to hazard tree_.LYeritle_d 
thro1tg h the proq:_c,hlJC in the U.than Forestry l\•fannaLi~JQ av..oid . ..rhdarge.s.c.akrcmoval of 
trc..c..s_bJ:_pr.apgcy owners th;:u ___ ;would othcn.vis..c_hc unclear wl~s;Ih!::IQXO.stt their spccili.~ 
areJJ.!J~ards. 'I'he definition of ha7'.tttd rree incorpcmttetl hy reference the pt;Q~hQHU:: . inJhc 
lJrhan l~'ore~tU:.-~:1.\illua] includc_.s_.aru.:valuation by,JJ_trg_e cisluUiSCS..SULO.£the_probability of 
failure, size of defective pan and target area b.cfou: _ _d_crermining~letbet a tree is a ha.z.ard. 
9 
Amendment No. 4 approved by council on 
11/27/2012 -Ordinance No. 12-09 
Amendments to the Urban Forestry Code Revis ions Based on Council Direction 
Amendment 4 (Policy Issue 7): Enhance puq)ose statement in Chapter 18.790 to draw a 
clearer link between rhe details in the Urban Forestry Manual and the overall purpose of the 
development code revisions. 
Code/Manual Section: Tigard Dcveluprnent Code Section 18.790.0 10 (Purpo~c) 
Purpose. The purpo~c of rhi~ chapter is to implement the City's urban forestry goals 
nrticulr~ted in the Comprehen~ive Plan as recommended by the Urban Forestry i\la~rer Plan7 
h)'...i~illlbfuhing; 
; \.,m · l 'rec._c_anopys;J>Y er reQ~lit<::Jnc nts.Joul~dopmCll.t.J:(:gardl<;:_~~ D CtlK 
f.11l1~J Ul1t ofgxi::;_tjpg !If::C..S.J.)JLSjlc_; 
It.... ·\ltcrnaJiy_r::;ro_ mcs;tiJl,gJt([\=anupv .. cs.2.D.:L[Cgtlircmcnts wht~n eQJ.liy!JJfnt 
cm:ir~maLiuru:.tio.us...o.rv.al.IJes arc pr<>vi<JnJ.; 
L Flexible !!J19. im:eoci\·c based requirc.mcnrs ro facilit<JJ[Jh~n.lantiug nf larg£ 
sta ture tt;CS.~ . ... aud.the presd:Yati.on_of existing trees ilmLsignif!C.il!li tree ~rnwe~; 
D. .. .. J)CJlllin'nl~Jll~J_h.aJ ensJ.Jrc sul.~lll.impkuwnrn ri<m of urbn!l fDrc,s.u:Lplaill 
dur.ing and after sire ckyclopmenr~ fl_nJ 
R_ m. __ £\j)rOC~>iJPJJDQI:iify~J.U:hau.lun:.str):. plans to adr.;ke.§_~ __ <,;.h;mt'C.Sthat.DCC.U.l: 
.Owing the dey_dn_prns:;nt..pr_oc..e..s.& 
Note: The corresponding commentary for the code amendments is amended as follo\vs to 
prO\· ide a record of legislative intent: 
18.790.0 I() Purpose 
The purpose h ,~.< been :<implified to statement cross reference~ the Comprehensive Plan and 
Urban l'orcstry Ma~ter Plan. Borh documents prm·ide the detailed policy basis for the 
cx:temive revisions to Chapter 1 H. 790. Examp)g~pfJh~' chJptcr_provisions th<JJ implcnwn.t 
.t.bc Ci ty's url1an fol:£2Jt:)'. goal~ arc pmv.idc.d_tn_,give nscr§J2f rhc_s;gclca.bi:ltcr.1llldtrSla11!.:liJJZ 
<>Lrhe overall purpose oLthc_cll#.p__CL 
10 
Amendment No. 5 not approved by council on 11/27/2012. 
This language will not be codified in 18.790.030 
Amendments to the Urban Forestry Code Revisions Based on Council Direction 
Amendment 5 (Policy Issue 7): Add the canopy requirements in the code to dra"v a clea.rer 
link between the details in the Urban Forestry :~v1anual and the overall purpose of the 
development code revisions. -----------------1 
Code/Manual Section: Tigard Development Code Section 18.790.030 (Urban Forestry 
Plan Requirements) 
:\. Urban Forestry Plan Requirements. r\n urban forestry plan shall d.cn±Pl±0fratc 
the foLlmvinf· effective tree C.iUlD.p.Y __ c.ov~.r_rc..q.till:.emrn.tli...lYill be met in the fqlJowiog__districts: 
E(f~c tiye I1e~ CalJQ.P.Y District 
_ CUYer..R~q~~t 
1 4.0.~Q__fQl;_oY...e.r.alL.site.and R:.l U R-3~ R-4.5 _ _nnd R-7_dis.tricts._cxc.ep.r_for schools 
l~J12L<,;_o_~_b_l_g_tg_L.trn~ t L1K11D . .0.5DLD1 
_})0<'\tfnr overall :;jtc I R-12 R -25 R-4Q, C-!::i._CC. C-C:i •. .C.:.P~ . MlJ.E •.. 11UE.c.l,_,11JJ.E,;:2. 
MUC,11URan<Ll:Edisui.as. e,A<;cpt for sd10ols (18.1 30.050(!_1} 
~lcu:...u:v:.cralL.sitc 
.::ill_urban forestry plan shall; 
!\ill.::CBD...,_.MUC.::l.l.:L and 1-li distri<:ts and for schools 
f1 R .130. 0 50([) )_iu_.alldis.u"kts. 
1. Be coordinated and approved by a landscape architect (the project landscape 
architect) or a pen::on possessing dual certifications as a certified arborist: and certified tree 
risk assessor (the project arborist); 
N ote: The co rresponding commentary for the code ameoclmenrs is amended as follows to 
pto,'ide a record of legislative intent: 
18.790.030 Urban Forestry Plan Requirements 
'fhis section is renamed to U rban Forestry P lan Requirements_. 
Th.e .... dfec rive tree .c.an_gpy_..c.over r.rgJ dx.cJnrru_~--~x.cjn.rhJdc.djn the code. to pro:v:ide us.exs of 
the (_odg a cleare,r_undc.rstnnding . .oLthc overall purpose_ of ths;_ LJ.Jban Forestry P.lo.,p_ 
l\bguirements without requiring them to read through the derails of thc_Urb.a.ILEor.e..s.trr 
tvlapual. The effective tree canopy cover requirements were <'xrensivdy tested during the 
peer review phase of the Urban Forestry Cilile.Jl.erisio.u.s_and were found to be achic\'ablc 
thr.o.ugh plautiugandpr.e.s..ervigg an_<unouqJ_Qf_ttee canopy that i~cr.c.p.table to the 
comm_unity . 'J'hc pq~t_rG_yiew rc.s.ultsaul.huound.in '1/.o.lmnc U._;wd a more qetnikd 
de.s.c.ription ofrhc canopy standards can be foundin_}~olume V of the ]eg;islative adoption 
lli!J"kagrJq_r the Urban Enn:srrv Codc.Revision.s .  
L-------------------·-· 
11 
Amendment No. 6 approved by council on 
11 /27/2012 - Ordinance No. 12-09 
Amendments to the Urban Forestry Code Revi sio ns Based on Council Direction 
Amendment 6 (Policy I ssue 8): R.cducc development costs for I\finor Land Partitions by 
not requiring arborists or landscape architects for partition projects that can meet the 
.requirements bv nlantin2: stree t trees in o nen soil volumes only. 
Code /Manual Section: Tigard D cYclopmcnt Code ~cctjon UUi)0.030. i\ (U rban F·orcs try 
Plan Rcquircmcnb) 
... ,\n urban fore~try plan shall : 
1. Be coordinated and apptoYcd by a landsca pe architect (the projec t landscape 
archi tect) or :1 person poss<:.~sing dual certifica tions a~ a ccrtiticd arborist and cerrified tree 
risk as~essor (the project arborisr), C.X.Ci:ptfo.r t\li nor I ;and Partitions that can cktno.nsm 
s;nn:+pU!ll1~UYith d~ . .CU\~ I,;!JS:C S::!:\JJQPJ: ... .C.QS.C.L.and .soib::Dlumc rcquir<'m~Jlt~J~an.ting sttcc..t 
J;rc.s;s jn__Qpcu_wiL:.-ohunc:i..un.l):; 
N o te : The corresponding commentary for the code amendments is amended as follows ro 
ptoYide a record of lcgislatin~ intent: 
18.790.030 Urban Forestry Plan RccpJircments 
Urba n forestry plans me t'CLJuircd to be dc,·eloped by a landscape architect o r a person 
ccrrified as bo th an arbo rist and ucc risk assessor. i\lany arborists arc dual certified, and 
adding the new rcquirem<:.nr fo r tree risk a:;scssmcnr will help ensure :;a fc condirio ns during 
and a ftcr construct inn. 1 .andscapc archirccrs often \Vork closely with arborists whe n 
developing urban forestry plans, so th e o prjon o f allowing land:->c tpc architects to sign off u n 
the plan:> has been added to rl:duce costs hy eliminating the need for hiring rwo urban 
forc~rrv con~ultan t~. 
,\rbori sts .an~11£tmhcapc .axchitecrs arl' _norJ:~qpired fo u\1illQ.d _,.and.P.artitions if the cffecriye 
rrgc .s::aJlQPI.S::<_n~cr_and_soil 1:olun1e n:cjuireru~m:ic.anhcmct.h}· pla.utUlf street trees iq_ qp~n 
soiL.:vo.lumc.s .. .onlr. ~l .ll<~ J?PU!n~~ of.th!:.:.cx.cmprioq L~ S.\1IC.&lus;c costs for smalLsc,ak.r.c.sidential 
ru;.~Jj&:~~l~wb~rc thc..rc.quin.::d level of~p~hi_aJjzc,;d pxofc.ssionaL,:xperti:;c is limited. 
12 
Housekeeping Amendments 1-13 approved by council on 11/27/2012 
Ordinance No. 12·09 and Ordinance No. 12·11 
Housekeepi ng Amendments to the Urban Forestry Code Revisions 
Amendment 1: Ensure consistency in the title of Chapter 8.02. Applies to Ordinance No. 
12-11 
Code/ Manual Section: Tigard Municipal Code Chapter 8.02 (Definitions, Penalties and 
Administrative Rules) 
TlG.AEI{....MllNLCli~ALCQ121,;, 
·ririe s 
URBAN l :·oRl;Sll{ Y 
Chapters: 
8.02 DEFINrJ 'IONS, PENALTIES .-\ND ~;Q,\rfl~J~J]};~:.UYJ~"RULES 
8.04 TR.EE PERMI'T PROCEDURES 
l 8.06 HAZA RD TREES 
8.08 STRI ~l ~T AND \li])1AN TRI: ES 
8.10 TREES IN SENSITIVE L:\NDS 
8.12 TREES THAT WERE REQUIRED wrrH DEVELOP~lENT 
8.14 TREES THAI' WERE PL\NTED USING THE CRBAN FORESTRY f-UND 
8.16 HERITAGE TREES 
Chapter 8.02 Dl;:r;·1NITIONS. Pl:NALTIES AND ADMJNISTRATIVE RULES 
'"""''"'""" "'00'0'0M0''0' ''''''' '''''''''''''''''''''''''-' '''''0''-'"'N•-----·-----·---------·----·----------····-···•M•o•ROO 
Amendment 2: Correct a cross reference in Section 8.02.020.( (D efining Words). Applies 
to Ordinance No. 12-11 
Code/Manual Section: Tigard J\:funicipal Code Section 8.02.020 (General Provisions) 
C. Defining \'{lords. Words used in this title and the Urban Forestry ·Manual have their 
normal dictionary meaning unless they are listed in Section 8.02.050. Words listed in Section 
8.02.04,50 have the specific meaning stated, unless the context clearly indicates another 
meamng. 
'--------------·-·-·---·-------·---··-·········-· ·····························-······· j 
13 
Housekeeping Amendments to the Urban Forestry Code Revisions 
Amendment 3: l~nsure the term "Diameter at breast height (DBF.I)" is placed in 
alphabetica.l order in Sec cion 8.02.050 (Definition of Specific Words). Applies to 
Ordinance No. 12-11 
Cod e/M anual Section: Tigard :\funicipal Code Section K.02.050 (Definition of ~pecific 
\X/ord s) 
~tl . "Driplim:'' - The o uter limit of a tree canopy projected to the ground. 
H,hi. "Diameter at breast height (DBH)"- The a,·eragc diameter of the trunk of a tree 
measured 4 1/ 2 feet aboH~ mean ground IcYcl ... 
!note: re\'erse order to place term:- in alphabetical order] 
14 
Housekeeping Amendments to the Urban Forestry Code Revisions 
Amendment 4: The Pacific Northwest Chapter of the International Society of 
Arboriculture (PNWISA) developed the current tree risk assessment metbodolot,ry and 
certification program. Due to the success of the program, the International Society of 
Arboriculrute (ISl\ ) is in the ptocess of adopting rhe program internationally. However, in 
the process of adopting the regjonal program for imernar.ional users, the ISA expects to 
modify some of its aspects. 
Terry Flanagan, local arborist, tree .risk instructor and President of the ISA., has advised o.n 
how to address the expected modifications in light of the pending adoption of the Urban 
Forestry Code Revisions. Specifically, he has advised generalizing the term "certified tree risk 
tl II . k II b f • • d . • h 'fj • assessor ro tree ns ' assessor ecausc o ant.Jctpate revtstons to r e cern catJon process, 
and replacing reference to "PN\XTISA" with "JS.A." to reflect the international scope of the 
program. Finally, he has advised retaining the numerical rating system since that is the 
currently adopted standard. If the numerical system is revised in the future, it may be 
replaced with the updated system. 
The following amendments implement these recommendations. Applies to Ordinance 
No. 12-09 and 12-11. O rdinance No. 12-09 affects Tit1e 18 also known as the 
Community Development Code while Ordinance No. 12-11 covers affected chapters 
in the Ti~ard Municipal Code consistintt of active and reserved Titles l-17. 
Code/Manual Section: Tigard .Municipal Code Section 8.02.050 (Detinition of ~pccific 
\'\lord !>) 
D . "Certified t]'rec risk assessor" - .An individual cenified ~ru!ualificd by 
the I ntcrnational Society of ;\rboriculrurc to conduct tree risk assessments. 
Jnote: re-lettering of the section i::: required to place terms in alphabetical orderJ 
Code/Manua l Section: Tigard rvlunicipal Code ~ection 8.02.050.1 (Hazard Tree Related 
Definitions) 
2. "Hazard tree - i\ ny tree or tree part that has been or could be determined by an 
independent cen:ified tree risk assessor to constitute a high len~ ] hazard requi1ing hazard tree 
abatement \V:ith an overall rninimum risk rating of 8 for trees or tree parts up to 4 inch DB I-I, 
9 for trees or tree parts greater than 4 inch and up to 20 inch DBf-1, or 10 for trees or tree 
parts greater than 20 inch DBH using tft.e.-.H=tost cunem verJion of the tree r.i sk assessment 
methodology developed by the International Society of Arboriculture in /\p_.P-eoqj;.'\_1 of th~,;. 
U;ban Forcsm· J\1f!J1\JIJ!. 
3. "llazard tree abatement" - The process of reducing or eliminating a hazard to an 
overall risk rarjng of less than 8 for trees or tree parts up to 4 inch DBH, 9 for trees or tree 
parts greater than 4 inch and up to 20 inch DBH, or 10 for trees or tree parts greater than 20 
15 
Housekeeping Amendments to the Urban Forestry Code Revisions 
~-.. -·-.-·.····· ···.· ············-·.·-·· -.··--··················-··.·········.·········-.··········· ··.·····-······· -······· -.. ·-·······-·. . . ··-···············.·······.· ·-. --·--·-········· · ·····.····-·······--=~l I inch DBH u~ing tfie-mf:tSt-ftH1~flt-'\"ef~f71'T-ft.f the tree ri~k as~cssmenr methodology 
I ~~:~~:;s:~r~~~~~~~er~~ ~ ~ ~i::;,t~~(:a~-~~)~~~~- ;;:· ;;~~~~~;t~i,~:~~:~:~ ~ ·~~:;e~~~;~~~;;~~~~~~~~f,~t~~l£~ 
I applicable rules and regulations. 
I ... I 
I Code /Manual Section: Tigard Development Code Chapter l 8.1 15 (List o f Terms) ! 
~'f:i.fi.ed· 'J 'rec Ri :-;k , \s ses~or 
S te Tret Rela!eJ D~jinition.r 
Tree Related Definitions 
• CaLiper 
• C<.' r ti ficd .'\ rbori~ r 
• ~etl Tree Risk ;\s~essor 
jnore: re -ordering of the section is rCLJuired to place terms in alphabetical order] 
Code/Manual Section: Tigard l)cYelopmcnt Code Section 1K.120.030 .. \ .l70 ( J'rcc-relatcd 
ddiniti< ms) 
c. "&t'ti-fiett 'free Risk .\sse::;sor" - ,\n individua l certified ili,:_~,\.Lql,!alifi~:d by the 
lnrcrnational Societ\· of ,\rboriculture to conduct tree risk assessments. 
g . ' 'Hazard Tree"- ,\ny tree or tree pan that ha~ been or could be determined by an 
independent certified trec ri~k a~sc ssor to constitute a high level hazard rec1uiring hazard tree 
;.1baremcnr wirh an m·erall minimum ri~k raring of B for trees or tree part:-> up to 4 inch DBH, 
9 for tree~ or tree p ans greater than 4 inch and up ro 20 inch D BH, or 10 for tree:-; or tree 
pans greater than 20 inch DBH using the most current Yer;; ion of the tree risk asses~ment 
methodology tb-cloped by the lrHefnfttionRl Socief): of .\rboriculrurc ini1PR~~~1~li:::> J. Dfih!.:: 
WJ:.l? .. anJ;:q~,:.c;~l.x~~J\li.! .. P.LJ.al. 
i h. '' !I azard Tree Abaternem"- The pruces:; of reducing or dirninaring a hazard to an 
! oven1ll ri sk rating of k~s than 8 for tree~ or tree parts up to 4 inch DB IJ, 9 for tree:; or tree 
I pans greater than 4 inch and up ro 20 inch DBH, or 10 for trees or tree parts greater than 20 
I inch DB I-I us ing ffie-ftK>:•t cunent Yer.;ion of rhc tree risk assessment methodology 
j deYCloped by the International Seetet'y-of \ rboriculrure ~\~i\..,.LQL.r.b~:.,.J.J .rJ?<Ulb..1tf:3:iJJ;.r 
I M~n.~@ through pruning, rree rem<wal or other means in a manner rhat complies with all 
I applicable rules and rcgularjons. 
1 [;10teo re-ordering of the section is required to p lace rem" in alphabetical o rder[ 
I ~<)<:1:€:!/~-~~ual Sec tion: Tiga~.~l Development Code Secti<~n 18.790Jl30 (U rban _ _l_~~?_restrv I 
]() 
Housekeeping Amendments to the Urban Forestry Code Revisions 
---··--··--·-····--··-·--······--·------------------· 
Plan Requirement:-;) 
.\ . Urban Forestry Plan RCLJuircmenr:-;. An urban forestry plan shall: 
1. Be coordinated and approved by a landscape architect (the project 
landscape architect) or a person pos:Je••sing dttft l certificllriom ftS thatj~bnrh a certified 
arborist and certified rree ri:-;k assessOJ (the project arborist); 
Code/Manual Section: Urban Forestry Ivlanual Secrjon 1 (lhzard Tree L·:valuation and 
Abatement P rocedure) 
Part 1. Informal Reconciliation 
... The claimant is encouraged to support their claim with documenw rjon by a cerr:ified rrcc 
risk assessor... 
Part 2. Formal Reconciliation 
... \Xiithin seven calendar day s of receip t of all the required application rnatcrials, the city shall 
g<1in access to the respondent's ptopert:y either voluntarily or w.ith a warrant pursuant to 
Chapter 1.16 of the Tigard :\Junicipal Code, conduc t a tree risk assessment by a certified tree 
risk t1Ssessor using the m o.:H current veraion of the tree risk assessment methodology 
deYelopcd by the International Sociery of. \ :rboxicultu:tT in .. Appcndi.\..J .JlLthe lJrba;JJ~QH'~tn: 
MamM.!l. determine if the definition of hazard tree in 'f igard i\lunicipal Code Chapter 8.02 
has been met and, if necessary, prescribe hazard tree abatement as defined .in 'I 'igard 
[v1unicipal Code Chapter 8.02 ... 
Code/Manual Section: Urban r;·orestry ~fanual Section 10 (Urban Forestry Plan 
Standards) 
Part 3. Urban Forestry Plan - Supplemental Report Requirements: 
C. T he name, acldre:;s, telephone number, email address; and IS.-\ certified arborisr 
number and PN\~' IS. \ certified H·ee ri!•lc ft'1SCJJO r number of the projecr arborist or stamp 
and registntt.ion number of the project landscape architect. 
Code/Manual Section: Urba n F'o res try i\:lanual Appendix 1 ( l'ree Risk Assessment Form) I 
I 
····---···---·- . I 
Certified Tree Risk Assessor: ! 1 J ~~~~·::::b:um~---~ --- - ~ I 
-·--··-·--·-·-----·-- --------------· 
Date of Evaluation: .~~~-------------------------
17 
! 
Housekeeping Amendments to the Urban Fo restry Code Revisions 
Certified Tn.T Ri$k :\ssc!'sor Signarurc: ______________ _____ _ 
Code/Manual Section: Urban Fon:stry 1\ lanual :\ppendix <) (1...' rban hJrcsrry Plan -
Supplern<.:ntal Repon Example Template) 
General Information 
JS. \ Certified _,\ rbori~t No.: 
H;;-\--(.,;ert+ftet..J- :1··:ree R:ts-k- A~~t-tr--Ne:-; 
Note: The cot-r<.:sponding commcnrary for the code amendments is amended as follow~ to 
provide a reco rd of legislative intent: 
10.120.030 Meaning of Specific \\ford s and T erms 
&mfi.et!-:(~:1:~,~ risk asses~or: 'Jlus term clarifies that eerttfi:ed tree risk assessor::; arc cerr.ified 
i .ndi\~.idual.s dl:<:med ~!.iJ:llili$,:,&1 by the International St>cicty of .:\rboriculturc (lS...:\)to cundJ.H,;t 
:t:t:l::~,J:A~!l~~g~?mcnts. .... I:h~.: .... Paci.fic ... N.ol~.rll\V.t~.st ... ChamJ;l. <J.f tbs:: ... ! .. nlt;.rtJ~~~,,QJ 
.\rb<v;ic.::Jtlwr.~~~'IS;\)d~;ydopcd .dlc c.w:.r.cm tree ri:-k asse~smentJll.t;;tJlP~ic}l_pgy aud 
c.crrjticatio'U!t:fJg.rnm-l.)\.JC _tq rbc.: SPC<::C.§~QLthc_ pmhr:t;am • .rhc.J .S.:\.is inthcprocl:ss.uf 
.~d~ )ptiQgJh~.J,lJ:QgJ:.amimcmationally .. Ho..\\'i.:.Y.<' r, it~_Jhe_nr<:>c.::r:>s <> [ !l&l.~>prjqg Jll<.: ,~,g~an:J,f\JX 
ik.~J..llilY~\;l.Q.aLus.c.rs •...  the ... lS..i.\ .... c.:x.p.e~ts .JQ~rno.di_fy ___ sn!.n~ ... P.f.it~ .... :l .~l2~l~...J:'l!Jtlci!2<lte.d 
ff . . -~ ~- f ·J " ·c: d . 1· " · 1 h '' l : c:" .J )J1Cl(_l__jCaij!) ll J §lCjJ,w.!...C.lll.CJ1Lf2 ___ _r Jc.JCX.:n:l CC.t:tl.1lC tl:Cl:nSJ.i..ttS.s.t:S,S.Ol' . WlULC:::_1RJIJ1 <;jlJiJ~ 
. k " Tl l d fi . . L. . k " . fl ·11 b 
.u:<.·c ns · a.s.s.c.s.s or .1 c.: ts:J!JlJUJ.<;. ;,c.,;,uJJ 1 on o tJ.:..c_ens ..... as.s.c.s.s.ox.: ..... .ls ...... e.~o. 2 .. c .... e.noJ.tg. 10 
r,c ~pnn<.lJn tl\~ antidpatcdchangl:s.... 
llazard tree: The term hazard tree has been made m ore specific to the Q;lJ+.cQ,J,t,EJ)J_1'fl~,:} 
Inrernarional Society of ),rboriculture S~p,~=.latl=l§ so rhar a more objective e\·aluation can be 
made as to what constitutes a hazard tree. .\ tiered sysrem of ra1jng hazards ensures the ri:;ks 
associated with small diameter tree pans are nor understated wh ile the risks associated with 
large diameter tree parr~ arc not ovcrsra ted. 
Ib~.1St1i0nJJKJ2.t:\.2Ccss. o Ladop tingth<: .... P..NWl~_ \. __ p_nJ.gramio t~lJlatio.ualli:.,_llo.w~~jn 
.tb.~_w;gc~~ §...\.2l:A9.muin.g ... J.h~~P£Qgr~xnJ.gr .. .in.tcrn.a.tio.n.al .... Liscr~ •. Jb.~ .. J S.,:\ __ ~,; __ :(_p_t;;_ s,;t;~ .... IP ... m\ .• ~dify ____ ~_ <?.!P.!; 
Pi",it;sJ:~;>Jl,CJ;,t,s,,""]:b,~~,:tn:~nU)NS\ClS,.;~JJPTn£ricJll ... b_as.cd .... s.}·s.trnlis .. .im;JusJe_g __  i!.L;.\pJ~.t;;.1JQ.i .O: ..... l ..... and 
r.e.{crcnccd ... br .... thc. .dc.fin.iti on ... of_':l1a_t:atdJ,ts;_!;_''.· ... l.f ... t.4.K., . .nY.U.Jr:.tic.al ... s \ 'S t<:an.is .rcs:is.~;~_din . .the .... fu_tu.r,~,:, 
ir mflr _hc.:r~'pli!ccd~.iJ:luhutpdfl.t~il~ ~.Jstl:m. 
I ... 
I [note: re-ordering of the commentary section is required to place terms in alphabetical order! 
I 
[_1_H. 7 9Q:~J3(~ __ l).:rban l' orestry Plan RC(J ~!E'=~.!:l_C:~_1-~~ ---
--------------.............. -- ...... ____ ......... _, _ _____ ___J 
lK 
Housekeeping Amendments to the Urban Forestry Code Revisions 
Urban forestry plans arc required to be developed by a landscape architect or a person 
cu:cified fW that is both att kCilificg arborisr and tree risk assessor. J\lany arborists p_osse.s.s 
!~rb qualifi.cari(211S sre dual certified, and adding the new requirement for tree risk 
assessment will help ensure safe conditiom during and after constmction. 
18.7<)0.070 .l\lodification tO the Urban Forestry Plan Component of an Approved Land 
Use Permit 
Two levels of modifications to the urban forestry plan component of an approved land use 
permit \v:iH be allowed. f\1inor modification will be completed as a sta ff level, technical 
review. 'fhe following items would be considered minor modifications: 
• Remova l of hazard trees if there is sufficient documenta6on by the arbori~U>r 
~ a certified tree ri:<l\ m1sessor; 
Amendment 5: Ensure consistency berwcen the Site Design Standards (Section 18.620.030) 
and Landscaping and Screening (Section 18.620.070) in the Tigaxcl Tdangle Design 
Standards. Applies to Ordinance No. 12-09 
Code/Manual Section: Tigard Development Code Scc6on 18.620.030.A (Sire Design 
Standards) 
3. Front yard setback design - Landscaping, an arcade, or a hard-surfaced expamion of 
the pedestrian path must be provided between a structure and a public street or accessway. 
If a building abuts more than one street, the required improvements shall be provided on all 
saeets. Landscaping shall be develo )ed ro thc_a . l · ~- • • -_:_:~..::..__ -~ ?(LQlO ... u 
, : _, ·- :· .. _ .,' , , . . . .... !-:lard-surfaced areas 
shall be constructed with scored concrete or modular paving materials. Benches and other 
street furnishings are encouraged. 'T'hese areas shall contribute to the minimum landscaping 
requiremem per ~ection 18.520.040B and Table 18.520.2. 
5. Parking locarion and landscape design -Parking for buildings or phases adjacent to 
pubbc street rights-of-way must be located to the side or rear of newly constructed buildings. 
If located on the side, parking is limited to 50°1t• of the street frontage~ f.H'td 1Yh~n __ abutring 
public greets, parking must be behind a landscaped area constructed to an L-1 l .. andscape 
l~~-d~ing Lot Sc.r.e.en Standard. 'fhe minimurn depth of the L-1 landscaped area is eight feet 
or is equal to the ruJ.ias;s;nt building setback, whichever is greater. .All o.th.e.r...site landscaping 
Interior side and rear yards shall be landscaped to an L-2 Landscape Genet~al Lau,d~aping 
Standard, except where s t•ide yard abuts a public Btrcet, where it shall be landscaped to an L 
1 Lsn(Lcitpe Standard. Jbc L-1 andJ ... :::2 ... Staodards an~Jnpn:..luliy...de.s_cllbcd in Section 
18.620.07\L 
I<J 
Housekeeping Amendments to the Urban Forestry Code Revisions 
Amendment 6: l•:nsure consistency between the Site Design Standards (Section 18.630.050) 
and Landscaping and Screening (Section 18.630.090) in the Washington Square R.cgional 
Center Design Srandards~~_li_e_s_t_o_O_rd_i_n_a_n_c_c_. N_ o_._l2 __ -0_9 ____________ ~ 
Code/Manu a l Section: Tigard DeYelopment Code Section 18.()30.05(L \ (Sire Design 
Standards) 
3. Front yard setback design. 
a. Pllrposc. The front yard is the most conspicuous face uf a building and requires 
special attention . . Places for {)eo pic_ and pede. strian movement. ht.·l_ps create an _ ac.~tiYe anJ 
safer street. liighcr level of . andscapc anticipates a more immediate \'isual result. 
b . Standard . l;o r scrbacb greater than 0 feet, land scaping, an arcade, or a hard-surfaced 
expansion o f the pedestrian path must be pnwided between a structure and a public street ur 
accessway. If a building abut s more than one street, the required improvements shall be 
proYidcd on all streets. Landscaping shall be develo )Cd to · ---~- ' c.cri.Dn 
1K.6JilJJ5iL;\..5 · , . ·- .·, ·, . . Hard -
surfaced areas shall be constructed with :::cored co ncrete or modular pa,·ing matcri"als. 
Benches and other srrcet furnishings arc encouraged. These a.re:1 s shall conrribute ro the 
minimum landscaping requirement per Section 18.52(J040.B and ·.rablc 18.520.2. 
5. Parking location and landscape design . 
<L Purpose . 'J'be emphasis on pedestrian access and a high c1ualiry streerscapc 
experience r<:cJuirc s th<H pri,·ate parking lots that abut public street~ should not be the 
predominant street feature. Where parking doc~ abut public streets, high quality landscaping 
should screen parking from adjacent pedestrian areas. 
b. Standard. Parking for buildings or phases adjacent to public street riglns-of-way must 
be lc>Cated to the siJc or rear of newly constructed buildings. \X!hcn buildings or phases arc 
adjacent to more than one public street, prirnary strect(s) shall be identified by the City 
where this requirement applies. In general, streets with higher functional classification will 
be identified as primary streets unless specific de sign or access factors fayor another street. 
T f located on the :::ide, parking is limited to 50°/;) o f the primary street frontage, ftftd \\iben 
abuttir!gJ~_yblil= srrccts parking must be behind a landscaped area consu·ucted to an L-1 
hmdscape &rking Lm }Scrrs,;.n standard. The minimum depth of the L- 1 landscaped area is 
eight feet or is CCjuaJ to the ~ building setback, whichever is greater. .ilLmhc.x ... sitc 
landsca]ling Interior :1ide and rear yard:; shall he landscaped to an I ,-2 landscape £'Jenera! 
La11dscapiug standard , except where l1 .lide yru:d ftbuu a publ:ic 3treet, where it ~·hall be 
landscnped to .m L 1 landscape ~~tandard. IIJ[J ,~Jan\JJ.::2...s:tand.lu:dsarc_1110...tc_fulli: 
describeq in_ ~S::~Iirm 18.G3U,D.9.0. 
2() 
Housekeeping Amendments to the Urban Forestry Code Revisions 
Amendment 7: Ensure consistency between the Site Desit,rn Standards (Section 
18.640.200. B) and Landscaping and Screening (Section l8.640.200.D) in the Durham Quarry 
_Q~~J?ridgeporr) Design Standards. Applies to Ordinance No. 12-09 
Code/Manual Section: Tigard Development Code Section l8.640.200.B (Site Design 
Standards) 
3. .Front va rd setback design. For setbacks greater than zero feet, landscaping, an arcade, 
or a hard -sudaced expansion of the sidewalk shall be proYided bet\veen a structure and a 
public street or accessway. If a building abuts more than one street, rhe required 
Improvements shall be provided on all streets . . Landscaping shall be developed to .rh~ 
ajlplic .. abk s.taudard in St;..<.·tionJ .B.04Q,Z.O.QJ~,.5 t~n L 1 l<tt~ndarcl on public ,1tfeet5 and an .L 3 
standard on accelSWftyJ. Hard-surfaced areas shall be constructed with scored concrete or 
modular paving matci:ials. Benches and orher street furnishings arc required. These areas 
shall contribute to the minimum lanclf>caping requirements. 
5. Parking location and landscape design. Parking for buildings or phases adjacent ro 
public street rights-of-,vay shall be located to the side or rear of newly constructed buildings. 
\XIhen buildings or phases are adjaceor to more than one public street, primary streer(s) shall 
be idcnrjfied where this requirement applies. If located on the side, parking is lim.itcd to 50°:o 
of the street fromage. ftftd \X!beo alnmi_og_pul)lic_s_tr.c.els.p.ark.ing must be behind a 
landscaped mea constructed ro an L-1 Land:Knpc Parkmg ...J.qr S~rcen Standard. 'fhe 
minimum depth of the L-1 landscaped area is eight feet or is cyual to the fl..ili!lccnt building 
setback, whichever is greater. AU otht'J §iti;;_J€1P.JJ~_haping lnrerior side and rear ynrcb shall be 
landscaped to an T.-2l.fmdtlcape .Grocral Landscaping Standard c.xcept \v'here ft :1icle yard 
t~burs a public :;treer, where it !lhall be land:<caped to an L 1 Land.•otpe Standard. Sec Section 
18.640.200.D 
Amendment 8: Correct a cross reference in Section 18.790.050.(.2 (.Adjustments ro 
Setbacks). Applies to Ordinance No. 12-09 
Code/Manual Section: Tigard Development Code Section 18.790.050.C.2 (!\djustmenrs to 
Setbacks) 
2. Adjustmems to Setbacks. 'fhe following setback reductions \.v1ll be allowed for lots 
preserving existing r.rees uf>iog the criteria in subsection h ,!l below. 
21 
Housekeeping Amendments to the Urban Forestry Code Revisions 
Amendment 9: Correct a cross reference in Section 18.790.050.C.3 (1\ djustments to 
Sidewalks). Applies to Ordinance No. 12-09 
Code/Manual Section: Tigard Development Code Sccrion 18.790.050.C.3 (Adjustments to 
Sidewalks) 
:1. .-\djusrrncn ts to Sidewalks . .. .It. a prcsct\Td tree is to be utilized as a :-: treer tree, it 
must meet the c riteria fou nd in the Landscaping and Screening Scct.ion 18.745.040 .. \.5~. 
22 
Housekeeping Amendments to the Urban Forestry Code Revisions 
Amendment 10: During the development of the tree grove preservation incentives, the 
initial proposal was to require permanent preservation and management of tree groves if 
applicants utilized any one of tl1e preservation incentives (density transfer, increased building 
height, setback reduction, etc.). While rhe Citizen Advisory Committee agreed that 
peJ:manenr preservation was appropriate, they advised staff to strike the management 
requirement. Their 1:arionale was that the management requirement could be seen as onerous 
by applicants and act ::ts a disincentive to preservation. Staff struck the management 
requirement for most of the preservation incentives, but inadvert:t~ntly failed to strike the 
requirement: for two of the incentives. The purpose of the follo'.ving amendments is to strike 
the remaining management requirements consistent \vith the Citizen Advisory Committee 
recommendar.ion. Applies to Ordinance No. 12-09 
Code/Manual Section: Tigard Development Code Section 18.790.050.D.3 (;\djustmems 
to Cornmercial Development Standards) 
3. .-\djustmeors to Commercinl Development Standards. :\djusrmenrs to Commercial 
Development Standards (fable 18.520.2) of up to 50 percent reduction in minimum 
setbacks and up to 10 feet additional building height are permitted pro,·ided: 
g. The significant tree grove is protected through an instn.nnent or action subject to 
approval by the director that demonstrates it will be permanently prcsern~d antl mana!!ecl such 
as: 
Code/Manual Section: Tigard De,·eloprnent Code Section 18.7<)lJ.050.D.6 (.\djustment to 
Street and Utility Standards) 
(i. .\cljustmcnt to Street and Utility Standards. 1 f requested, d1e director shall use hi s or 
her discre6on when considering adjustments to Chapter J 8.81 0, Street and Utility 
Improvement Standards and Section 18.745.040, Street Trees provided: 
b. 'T'he significant rrcc grove is protected through an instmmcnt or anion subject to 
approval by the director that demonstrates it will be permanently preserved nnd rrHt nHfFed 
such as: 
23 
Housekeeping Amendments to the Urban Forestry Code Revisions 
Amendment 11: One of the goals when revising the Urban Forestry Standards for 
Development was to clarify when an urban fmestry plan for development is "in effect" . 'The 
purpose of the clarification is to avoid the current' situation where future homeowners must 
amend their land usc approvals to remove trees that were required '.vith development. 
Initially, the term "active" was used bur was later replaced with "in effect" since that term is 
more commonly used in the land use process. The term "active" was inadvertently left in 
Section 18.790.060 and the purpose of this amendment is to replace it with "in effect". 
Applies to Ordinance No. 12-09 
Code/Manual Section: Tigard Development Code Section 18.790.060 (Urban Forestry 
Plan J m plemen ration) 
B. Inspections. lmplcmentarjon of rhc urban forestry plan shall be inspected, 
documcntclj and reponed by the project arborist or landscape architect whenen:r an urban 
forestry plan i~  in.J:ifu.cr. ... 
Amendment 12: Correct spelling error of a tree's common nan1c in the Urban Forestry 
Manual. Volume IV- Urban Forestry Manual- Not codified. 
Code/Manual Section: Urban Forestry i\ianual ;\ppendix 2 (Strcl:t Tree List- Small 
Stature Trees) 
Glorybbwcr ... 
24 
Housekeeping Amendments to the Urban Forestry Code Revisions 
Amendment 13: Generalize cross references from the code to the Urban Forestry Manmtl .. 
1 f the adminisr.rative rules a.re modified du.ring the upcoming adm.inistrativc rule adoption 
process or any other future date, this will make the process more efficient by avoiding the 
necessity of making changes to co.r.responding cross references in the code. Applies to 
Ordinance No. 12-09 and 12-11. Ordinance No. 12-09 affects Title 18 also known as 
the Community Development Code while Ordinance No. 12-11 covers affected 
chapters in the Tigard Municipal Code consisting of active and reserved Titles 1-17. 
Code/Manual Section: Tigard i\Iunicipal Code Sccrion 8.02.050. I (Hazard rrce related 
definitions) 
1. "Claimant" - ,\ny person that belie,·es in good faith there is a hazard tree on a 
property, can demonstrate that their l.ife, limb or property has the potential to be impacted 
by said tree and seeks resolution through the H.azard 'J'ree I~valuarion and Abatement 
Procedure specified in Section 1 of rhc Urban l''orcstry Manual. 
5. "Respondent" - Any person that receives norice From a claimant seeking rcsolurjon 
through the Jiazard Tree Evaluation and A batemcnt Procedure specified in Section 1 of rhe 
Urban Forestry :Manual. 
Code/Manual Section: Tigard l\Junicipal Code Section 8.06.030 (Hazard Tree l~\·aluadon 
and . \batcmem Procedure) 
:\ . :\ny claimant may seck resolution through the llazard Tree Evaluation and .\baiemenr 
Procedure specified in Section 1 of tJ1e Urban Forestry l\lanual. 
B. Once initiated by the claimant, both the claimant and respondent ha\'c an obligation to 
complete rhe Hazard 'free T~valuatjon and Abatement Procedure specified in Section 1 of the 
Urban Forestry l\:fanual. Failure of the claimant or respondent m perform the.i.r obligations 
specified in the Hazard Tree Evaluation anc..l i\barcment Procedure con~titutes a viola6on of 
this code by the negligent party. 
Code/Manual Section: T'igard i\Junicip:1l Code Section 8.06.040 (Emergency Abatement 
Procedure) 
If the city has reason to belieYc a hazard tree poses an immediate danger and there is not 
enough rime to complete the Hazard Tree Evaluation and Abatement Procedure in ~:ectiotJ 1 
e.f the Urban Foresrrv ~lanual, the citv mny choose to take immediate remedial acrion as 
, . .I • 
defined in Section 1.1 6.150 of the Tigard Municipal Code. 
Code/Manual Section: 'J'igard 1v1unicipal Code Section 8.08.030 (Street Tree Plamjng) 
No person shall plant a srreet tree without prior written approval obtained through the City 
25 
Housekeeping Amendments to the Urban Forestry Code Revisions 
\1anagcr Dcci!'ion \faking Procedures detailed in Section f\.04.020 u~ing the apprmal Ctiteria in 
&efjon 2, part 1 of thcSt.t:c~:t1·r~J>Jaqting Stnp\.4'lJ:,sJ~jp the Urban l 'oresrry !\ lanual. 
Code/Manual Section: Tigard i\lunicipal Code Sccrjon K08.040 (Stn:ct Tree ,\1aintcn<H1Cc) 
;\. I\11 sr.rcct rrees :;hall be maintained in a manner consistent with the s;;itreet (,lree 
m l\laintenancc ~~t:mdards specified in ?;eefton 2, pan 2 of the Urban Forestry I\lanual. 
Code/Manual Secrion: Tigard \Junicipal Code Section 8.08.050 (Strecr Tree Removal) 
. \ . The City ,\lanagn Decision i\ l aking Procedures detailed in Section R.04.020 using the 
approval criteria in ~ett:itn1 3, part 1 of tbJ,~,,;5trcct1'rceR.emm.: aLSt~ the Urban 
l 'urcstry J\lanual; or 
Code/Manual Section: Tigard f\Iunicipal Code Section 8.08.060 (Median Tree P Janrjng) 
No person shall plant a m edian tree wid10ur prior wr.itten approval obtained through the 
City Manager Decision i\Iaking Procedure!' detailed in Sect:ion H.04.020 using rhc npprond 
criteria in ~eeciun '1, ptm 1 of JlwJYlrdian]'r~J::l\liltingStandard~ in rhe l.: rban l 'oresrry 
f'vlanual. 
I ... 
~,- Cod. e/M. a. nual Section: T iga rd Municipal Code Section 8.0R.070 (l\Icdian Tree 
i\:lain tcnancc) 
. \ . , \II median trees shall be maintained in a manner consi!'tem with the m~Jeclian tlree 
m,.\laintenance ~~tanclards specified in ?;ec-tton 1, pan ? of the Urban Forestry l\f anual. 
Code/Manual Section: Tigard i\lunicipal Code Section 8.08JJ80 (i\ ledian '] 'ree Rcrnoval) 
.\ . The City i\lanager Deci!'ion ,\laking Procedure~ detailed in Section 8.04.020 u!'ing rhe 
approval cri teria in ~efti+71"1 5, part 1 of th~,;,,,i\1£:&1illnTr~.:~~\cmuvaLStarJdarill.iu the t :rban 
Forestry Manual; or 
Code/Manual Section: Tigard i\lunicipal Code Section 8.H).()40 (Sensitive Lands Tree 
Removal) 
. \ . ·rhe City Manager Deci~ion Making Procedures derailed in Section 8.04.020 using the 
appron l criteria in ~eetiBtJ 6, pan 1 of the Smf'itiY ~.:J,,ands .. :.Lu:.c .... lS,rnlolal ;-:;_t<)Jl!.,hmh in rl1c 
Urban Forestry Manual; or 
Code/Manual Sectjon: Tigard \1unicipal Code Section 8.12.040 (R.emm'al of 'l'rccs Thar 
\Vcrc T\.e q~~:~~- \X'ith De\·eloprnenr) 
::y, 
Housekeeping Amendments to the Urban Forestry Code Revisions 
,-------------------·-------······-·-····--· - ----
A The City Manager Decision [\:laking Procedures detailed in Sectjon ~t04.020 using the 
approval criteria in &ette11--f., pan 1 of thc_Dcvdopmt1U.TrccRcruo:v.ai Stand.i!.r9.~__in the 
Utban r:orestry J\. !anual; o.r 
Code/Manua l Section: Tigard J\.1unicipa1 Code Section R.14.040 (Remov;~l ofT'rees that 
were Planted Using the Urban Forest1)' Fund) 
A. 'fhe City Manager Dcci:;ion Making Procedures detailed in Section 8.04.020 using the 
approval criteria in Sectjon 8, part 1 of IDJ.d .. L.J;Q.~n_[.PJ.&:S:tQ:_ E:uud :Itc5::J\~:mo\:::t.lSt!l41QJ\td~in 
the U rban Forestry Manual; or 
Code/Manual Section: Tigard ;\lunicipal Code Secrion 8.16.070 (l'tem<wal of Heritage 
Tree Desit,rrwtion) 
.-\. The City ]\fanager Decision Making Procedures detailed in Section 8.04.020 using the 
approval criteria in Section 9, pnrt I of J!.Js_ Hr;tit;ngs: "J.J;£~ DcsignationJ.\emODlLSt<Ulbllild_~_ iu 
the Urban Forestry i\bnual; or 
Code/Manual Section: 'figard Development Code Section 1 H. 745.040. ,\ (S treet Tree 
Standards) 
J. Street trees shall be recjuirccl as part of the approYal process for Conditional Use 
(fype H I), Downrmvn Design Revie\v ( I'ype Il and JJI), 'Minor Land Partition (f ype 
II), Planned Dewlopmcnt ( I'ypc III), Site Development Redew (l'ype II) and 
Subdivision (fypc IT and III) permit:c;. 
2. 'T'he nunimum number of reyuired street trees shall be determined by dividing the 
linear amoum of street frontage within or adjacent to rhe sire (in feet) by 40 feet. 
\Xlhen the result is a fraction, the minimum number of rcyuired sr.reet trees shall be 
determined by rounding to the nearest whole number. 
3. Street trees rcgu.ired by this sec6on shall be planted according to the .S_Ut:ct Ir~.c 
Plant:ll1g ~~tandards in Section 2 of rhe Urban h>restry iv[anual. 
4. Srreet trees required by this section shall be provided adequate soil volumes according 
to the .Strc~tl:r.~:;~m .SuiLYnlW.lJ~ s.Standards .in Section 12 of the Urban I •'orestry 
l\·1anual. 
5. Street trees required by this section shall be planted within the right of \vay whenever 
practicable according to the Sttb:cJ'[th~~PJanting s,~tandards in Sectjon 2 of the Urban 
Forcstrr Manual. Street '!~-~s may be r.1_anted no more than 6 f<.:er ftom ~he right of 1 
2'" 
Housekeeping Amendments to the Urban Forestry Code Revis ions 
way according to the ~tr~.:<:t 't:r~.:!.:""l?j!!.miug :;~tandards in Section 2 of the Urban 
h ;rcs try ,\lanual when planting within the right ()f way, is not nracricabk . 
(~. ,\n exi sting tree rnay be used to meet the street m:e standards provided that: 
a. The largest percemage of the tree trunk immediately above the trunk flare or root 
buttresses is either \Vithin the subject site or \vithin the right of \\'ay iiTnnediatcly 
adjacent to thc subject site; 
b. The tree would he permitted as a street tree according to rhe :itJ:CCT11:.<:c.J?lanting 
i} US.l c~J,>iL'l'"9hlml' :;~ tandards in ~t)ft:r~d I? of the Urban Forestry l\Janual if 
it werc newly planted; and 
c. The trcc is shown as preserved in the Tree Prescn·arion and RcmoYal site plan 
(per lH. / 90.030.,\ .2). Tree Canopy C:onr site plan (per H~./90 . 0:10 .. \ .. ) ) and 
s:3upp lemental r.l1epon (per 18.790.030.:\.4) of a concurrent urban forestry· plan 
and is eligible fo r credit towards rhe effecti,·e tree canopy cover of the site. 
7. J n cases where ir is not practicable w prm-idc the m inimum nurnber of lTLJUircd ~tn: et 
trees, the Director may allow the applicant to remit payment inro rhe Urban l;ores try Fund 
for tree plan6ng and early establishment in an amount eLJUiv alcnt to the City's cost to plant 
and maintain a street tree for three (3) years (per the Street Tree J:~l!!JJ.Jjog ~~tandards in 
~~ec:tion? of the Urban 1 1orcsrry f\lanual) for each tree below the minimum tC(.Juired. 
Code/Manual Section: Tigard De\-clopment Code Section 18. 7 ~ 5 . 050.E. I .a (Screening of 
parking and loading areas is rc<.juired) 
(4) All parking areas, including parking spaces and aisles, shall be required to achien· at 
lca::;r 10°·u tree canopy cover at maturity direcdy aboYe the parking area in accor:dance \Vith 
the Parking Lor Tree Canopy Standards in ~ee6on 13 of the Urban l :on:stry :\lanual. 
Code/Manual Section: Tigard Development Code Section lR. / 90.030 (Urban Forestry 
Plan R.eLluircments) 
;\. Urban J.'orcstry Plan Re<.p.lirernents. ;\n urban forestTy plan :;hall: 
1. Be coordinated nnd approved by a bndscapc architect (the project landscape 
architect ) or a person po:;sessing dual certification::; a:-: a ccrrjfied arhorisr and ccrr.ificd tree 
ri sk assessor (the project arburist): 
2. ,\leer the +J)ee rEresernrion and dlemoval ~~irc rPlan :-> randard s in &eeeen- l+t,-rtrt'f 
.f-e.f the Urban Forcstt} _~}•: r:\~<1 1_; ___ _ 
2X 
Housekeeping Amendments to the Urban Forestry Code Revisions 
3. .'vleet the tirc: .. T e(;anopy s~ite pElan standards in ~ection 10. nart 2 of the Urban 
Forestry l\fanual; and 
4. 1\Jeet the s~uppkmenn1l rE,cpon standards in &ffiEtt't~, part 3-trf the Urban 
I;orestry l\fanual.. 
B. Tree Canopy r:ce .. If the sS.upplcmenralrReport demonstrates that the applicable 
standard percent effective tree canopy cover in Section 10, parr 3, item N will nor be 
provided through any combination of tree planrjng or preservatjon for the overall 
de\Tlopmcnt site (excluding streets) or that the 15 percent effective tree canopy coyer will 
not be pnwided through any combinario n o f tree planting o.t prcscxvation for any individual 
lot or tract in the R.-1, R-2, R-3.5, R-4. 5 and R-7 disu-icts (when the overall development site 
meers or exceeds the standard percent effect.i\'1:. tree canopy cover), then the appbcant shall 
provide the city a tree canopy fee according to the methodolot,ry outlined in th~' J 'r<:r .. Caaqm; 
I:ccCakulationR.cqnitclU.~nt.~iu ~ecrion 10, part 'I of the Urban F~)tesrry Manual. 
Code/Manu al Section: Tigard De\·dopmcnt Code Section 18.790.040 (Discrc6onary 
Urb;1 n Forestry Plan Rc\"iew Oprion) 
.. \ . General Provisions. ln lieu of providing payment of a tree canopy fcc when less than 
the standard e ffcctiYe tree canopy e<wer required by Secrion 10, part 3 of the Urban Fore:•rry 
Manual will be provided, an applicant may apply for a discrc6onary urban forestry plan 
review. The discretionary urban fore stry plan rcvie·w cannot be used w modify an already 
approved urban forestry plan. any tree preservation or rn..:e planting requirements established 
as part of another land usc review approvaL or any tree preservation o r tree planting 
tTl]uircmcnts required by another chapter in this tide. 
Code/Manual Section: Tigard Development Code Section 18.79U.050.D .1 (Reduction of 
I\1inimum D ensity) 
b . The project arborisr or landscape architect certifies the preservation is such that the 
connecti,·ir:y and viability of the remaining si6rnificant tree gron' is m aximized \vhilc 
balancing the SjgJ . .-tifi.<;Jl!lt]);gcf=~,m,h<;,J;;;i;§~Q:f!ti.JJ.JJ e£,;onsiderations in F.ection 10, part 
.§...+Jf the Urban Forestry ?vianual; and 
Code/Manual Section: Tigard Dc\·clopmcnt Code Section 1 H. 7 ~)0.050.D.2.a (Density ml1y 
be transferred provided that:) 
(ii) The project arborist or landscape architect cerrifies the preservation is 
~uch thal the connecdYity and viability of the remaining sit,mificant tree 
____ , ______________ __lS!cJve is rnaximi%cd 'vhile_l!.!~lancing t~1.e Sjgnific<wLIJG<:>(iJO:¥:e 
2') 
! 
Housekeeping Amendments to the Urban Forestry Code Revisions 
}2rts~en:atiun e(:_omidcratio m in See tion 10, parr 5 of the Urban 
l;orestJT i\lanual: 
Code/Manual Section: Tiga rd D evelo pment Code Scc rjun 1 8.7SHl.OSO.D.3 ( \d ju:wnen ts 
ro Commercial DeH~ lopment Standard s) 
I ... 
I b. The pro jec t arboris t or landsc ape archi tec t certifies the presetTation is such that the 
conncc ti,·itv and ,·iab ilitv o f the remaining significant tree (rroye is m aximized while ~ J <.. b 
b alancing the ~igJJifis;:a tn 'l'r<::<:: .iiW..+:.G..J?x<::>i£P:ation e~onsiderari<>n s in See rion 1(};-pai' t 
-5-B-f the U rban l 'oresrrv 1\1anual: 
Code /Manual Section: T igard D c,·el o pment Code Secrio n 18. 790 .050.1).4 (A. djustmenrs 
to Indu strial Den.·lopment S tandard s) 
b . The projec t arbo ri sr o r landscape architec t cerrj fi es the presct-v;uio n is such that the 
conncc ti,·ity and viability of rh e runaining significant trct: g run : is maximized wh ile 
b alancing the ~J,_~lli·J·rrr(in)~d?xcsc.rD~..tit.ll1 e.C<m ~idcration s in ~tt>tll0;-1)ftft 
S-ttf the U rban l'o rcsrry I\lanual;; 
Code/Manual Section: T igard Dnt:lo pmcn t Code Section 18. 7<)0.050. D. 5 (,\djusnncnr to 
1\ l inimum E ffective T ree Canopy CoYer Rt:<.:]uin.: men t) 
b . ·rhe p ro jec t t~rboris t o r landscap e architect ct:njfics the presen ·atiun is such th at the 
connecti,·iry and Yiability of the remaining signi ficant tree gron· is m aximi%ed w hile 
balancing the Signifi<:.;.iUlt :Lt:.~~ (~J~<.':JX~Jiq_n cb:onsidcratio n s in Section H~-t 
S-ttf the Urban Forestrv Manual: 
Code/ Manual Section: Tigard Devel o pment C ode St:ctjon 18. 790.U50. D (J (, \ djustmcnt to 
Stree t ;111d Utility Standard s) 
a. T he ad ju :; rrnt:nts w ill facili ta tt: prcst:tTa rion and help to m axim.izc the connecti,·ity 
anJ Yiab ility o f a signi tlcant tree g ro n · \vhi lc balancing the S igui.tlc.aqr·Lrn~ \~ Hl'lJ~ 
ErcsrrYation. e[~cmsidcra rion s in ~~eccion 10, p art 5 of the Urban l 'orcstry 1\'fanual; 
Code/ Manu al Section: Tigard l)cye lopm enr Code Sectio n 18.79(J. 0(J0 (Urban l;orcsrry 
Plan Implemt:ntatio n) 
B. J n spec tiom . ] mplemcn ta tion of the urban forestry plan shall be in spec ted , 
documented and reported by the projec t arbo rist o r landscape architect w hcne,·er an urban 
forcsrry pl an is ac tin· . ln add ition , no perso n m ay refuse entry o r access to the directo r fo r 
1 the p urpose of m o nitu ring the urba n fo restry plan on any site with an c ffectiYe u rb an 
I forestn · plan. ' l 'hc ilnspection r,E.e~~Ii t.~~mcnrs in Sec tion 11' r ~ut 1 ttf r) ~~ - ~Jrba n l"ore srry 
3l.i 
Housekeeping Amendments to the Urban Forestry Code Revisions 
r P.:f an ual shall apply to sites with -a n -~-ff~:~ij~:~ ~;;:t;~;-~--f~ rcs_t_~); [~i~;;-.-
C. Tree Establishment. The establishment of all tree:; shown robe planted in the (.[rec 
e,Canopy sSite pf,lan (per 1 R. 790.030.4\ .3) and l:<;;iupplcmental rJleport (per 18. 790.030./\.4) 
of a previously approved urban forestry plan shall be guaranteed and required according to 
the t.J)ee eEstablishmcnt ·rJ.icquiremenrs in Section 11, part 2 of the Urban Forestry J\1anual. 
D . Urban Forest Inventory . Spatial and species specific dara shall be collected according 
to the tt.Urban +l;:orcstry iJm·entory rB,equirements in Scction41, part 3 of the Urban 
ForestTy 1\'!anual for each open grown tree and area of stand grown trees in the tirec 
e£,:anopy ~;;iite rJ:!Ian (per 18. 790.030.;\ . .3) and s~upplemcntal rE,eport (per 18. 790.030.A4) 
, of a preYiously approved urban forestry plan. 
I I ... 
I I Code/Manual Section: Tigard Development Code Section 18.7()0.070.B (Exemptions) 
B. 1.?-xemptions. The following acti,·ities shall be exempt frorn the Type I Modification 
to the U rban Forestry Plan Component of an :\pprovcd Land Usc Permit proces!': 
1. Removal of any tree shown as prcsef\Td in the tircc e!:anopy sS.itc p£lan (per 
18. 790.030 .. -\.3) and sS.upplemental :f;)leport (per 18.790.030. :\.4) of a previously approved 
urban forestry plan provided: 
a. The project arborist or landscape architect pr<Nides a written report prior to removal 
attesting that either the condidon radng (per Section 10, part 3, item D.7 of the Urhan 
Forc.m·y Manual) or suitability of preservmion raring (per Section 10, p:-m 3, item D.8 of the 
Supj:2kmentalJl<:;J).O..rt..Re..quix.cmc.ntsi.tlthc Urban l'o restry i\Janual) of the rrec has changed 
to a raring of less than :2; and 
b. A revised !Tree c~anopy sS.itc r£lan and sSupplememal fll,eport arc submitted for 
re,·iew and appt(wal prior to removal that reflect the proposed changes w the previously 
apprond urban forestry plan. The n.·, ·iscd tirec c,Canopy sS.ite r£lan and sS.upplemental 
arho.r1st f;)leport shall demonstrate how the effective tree canopy cover requirements in . 
Section 10, pan 3 of the Urban r:orestry Manual \Vill be provided by tree planting, I 
ptcscrvat;on and/ or payme~=~~:ee canopy fcc ;n lieu ufpla=tr:g o:~~,~~~ _j 
3 l 
CITY OF TIGARD, OREGON 
TIGARD CITY COUNCIL 
ORDINANCE N O. 12- I o 
:\N ORDINANCE ADOPTING COMPREHENSIVE PLAN AMENDMENT CPA 2011-00004 TO 
INCORPORi\TE A SIGNIFICANT TREE GROVES MAP INTO THE TIGARD COMPREHENSIVE 
PLAN. 
WHEREAS, on June 3, 2008 the Tigard City Council adopted an Urban Forest section as part of the 
Comprehensive Plan in order to establish broad goals and policies to guide the long-term management and 
enhancement of the urban forest; and 
\X'HEREAS, on August 10, 2010 the Tigard City Council readopted the Urban Forest section as part of the 
Comprehensive Plan in order to provide more detailed findings to further support and explain the rationale for 
the city's urban forestry goals and policies; and 
WHEREAS, Policy 2.2.1 of the Tigard Comprehensive Plan requires the city to periodically update policies, 
regulations and standards regarding the city's urban forestry program; and 
\X'HEREAS, Policy 2.2.11 of the Tigard Comprehensive Plan requires the city to develop and implement a 
citywide Urban Forestry Master Plan to guide the update of the city's urban forestry program; and 
WHEREAS, on November 10, 2009, the Tigard City Council adopted Resolution 09-69 accepting the City of 
Tigard's Urban Forestry Master Plan; and 
WHEREAS, the accepted Urban Forestry Master Plan analyzed the past and present conditions of Tigard's 
Urban Forest, was developed through a public process, and sets forth a course of action for Tigard's urban 
forestry program through 2016; and 
WHEREAS, the Urban Forestry Master Plan recommendations include the development of flexible and 
incentive based land use regulations for significant tree grove preservation; and 
\X'HEREAS, on February 16, 2010, the Tigard City Council directed staff to implement the Community 
Development Code related recommendations in the Urban Forestry Master Plan, which include the 
development of flexible and incentive based land use regulations for significant tree grove preservation; and 
WHEREAS, a public involvement plan was adopted by the city's Committee for Citizen Involvement in 2010 
and implemented during the course of the Urban Forestry Code Revisions project to guide city staff and 
decision makers; and 
WHEREAS, a council appointed Citizen Advisory Committee charged with advising project staff during the 
Urban Forestry Code Revisions project met 11 times between June 2010 and September 2011 and reached 
consensus on the flexible and incentive based land use regulations for tree grove preservation in Section 
18. 790.050.D through a set of "tree grove preservation incentives guiding principles"; and 
WHEREAS, a Technical Advisory Committee comprised of city staff and agency representatives was 
concurrendy convened to advise project staff on technical aspects during the Urban Forestry Code Revisions 
project, met 14 times between June 2010 and November 2011 and reached consensus on the technical 
ORDINANCE No. 12- J D 
Page 1 of 4 
feasibility of the flexible and incentive based land use regulations for tree grove preservation in Section 
18.790.050.D; and 
WHEREAS, the process for adopting land use regulations for the preservation of natural resources, including 
the flexible and incentive based land use regulations for tree grove preservation in Section 18.790.050.D (to be 
adopted through DCA 2011-00002), must comply \vith Statewide Planning GoalS Rule requirements; and 
\X'HEREAS, Statewide Planning Goal 5 Rule requires an im'entory of regulated natural resources, coordination 
v.-ith affected property owners, an Environmental, Social, Economic and Energy (ESEE) _\nalysis of the 
consequences of a decision to allow, limit, or prohibit uses that conflict with the inventoried natural resources, 
and adoption of a map identifying the boundaries of the inventoried natural resources; and 
WHEREAS, on July 20, 2012, the Tigard City Council and Planning Commission met with project staff and 
consultants prior to the inventory stage and concurred that tree groves should be part of the inventory only if 
they meet the following deftnition: "a 2-acre or larger contiguous, healthy canopy of predominately native trees 
that provide scenic, aesthetic, environmental or other functional values to the community."; and 
\X'HERE..A.S, project staff and consultants conducted an inventory using the abm-e deftnition and identifted and 
mapped 70 tree groves covering 544 acres; and 
\X'HERE.:\S, project staff and consultants held an open house with affected property owners on 
October 6, 2010, to discuss the inventory results, review the map and receive input prior to the drafting of 
flexible and incentive based land use regulations for tree grove preservation in Section 18.790.050.D; and 
WHERE_'\S, project staff and consultants drafted flexible and incentive based land use regulations for tree 
grove preservation in Section 18.790.050.D, which are to be adopted through DCA 2011 -00002 and include 
allowed reduction in minimum density, density transfer, increased building height, reduced setbacks, 
adjustments to Urban Forestry Plan requirements and adjustments to street and utility standards to facilitate the 
preservation of inventoried tree groves as part of the land development process; and 
\X'HEREAS, project staff and consultants held an open house with affected property owners on 
February 17, 2011, to discuss the draft flexible and incentive based land use regulations for tree grove 
preservation in Section 18.790.050.D and found that the draft regulations were generally supported by affected 
property owners; and 
WHEREAS, project staff and consultants drafted an ESEE Analysis of the consequences of a decision to 
allow, limit or prohibit uses that conflict with the 70 inventoried and mapped tree groves identified as 
signiftcant, and determined that the proposed limited preservation option in Section 18.790.050.D, which 
provides flexible and incentive based land use regulations for significant tree grove preservation, is the preferred 
option; and 
WHEREAS, on January 13, 2012, prior to the legislative adoption phase of the Urban Forestry Code Revisions 
project, 14,225 public hearing notices were sent to all Tigard property owners consistent with Measure 56 
requirements as further described in the findings of the staff report beginning on page 419 of Urban Forestry 
Code Revisions Volume II; and 
\X.HEREAS, the public response at the citywide open house on December 8, 2011 and after the Measure 56 
notices v.'ere sent on January 13, 2012, was generally supportive of the inventoried and mapped tree groves and 
the proposed limited preservation option in Section 18.790.050.D that provides flexible and incentive based 
land use regulations for significant tree grove preservation; and 
ORDINANCE No. 12- i 0 
Page 2 of 4 
WHEREAS, the Tigard Planning Commission reviewed at one workshop and four public hearings between 
January 2012 and May 2012 the inventoried and mapped tree groves and the limited preservation option in 
Section 18.790.050.D that provides flexible and incentive based land use regulations for significant tree grove 
preservation, the ESEE Analysis that includes findings that support the limited preservation option in Section 
18.790.050.D and the significant tree groves map (CPA 2011-00004) that identifies the location of the 70 
significant tree groves that are eligible for the flexible and incentive based land use regulations for significant 
tree grove preservation in Section 18.790.050.D; and 
WHEREAS, while the Tigard Planning Commission supported the flexible and incentive based land use 
regulations in Section 18.790.050.D and the ESEE Analysis, they recommended amending the boundaries of 
significant tree groves #38 and #62 in the significant tree groves map (CPA 2011-00004) to reflect recent tree 
removal from those groves; and 
WHEREAS, on May 7, 2012, the Tigard Planning Commission made a unanimous recommendation of 
approval of CPA 2011-00004 as amended regarding the boundaries of significant tree groves #38 and #62 to 
City Council by motion and unanimous vote; and 
\X'HEREAS, as described in the findings of the staff report beginning on page 419 of Urban Forestry Code 
Revisions Volume II, the Planning Commission found the city complied with Statewide Planning Goal 5 Rule 
requirements throughout the development of flexible and incentive based land use regulations for tree groYe 
preservation in Section 18.790.050.D; and 
\"X:'HEREAS, on the following dates in 2012: July 24, August 14, September 11, October 23, November 13, 
and November 27, Tigard City Council held a public hearing to consider the Commission's 
recommendation on CPA 2011 -00004; and 
\X'HEREAS, Tigard City Council finds it necessary to delay implementation of the Urban Forestry Code 
Revisions, which include CPA 2011 -00004, until March 1, 2013, to ensure an orderly administrative 
transition to the new urban forestry regulations; and 
\X'HEREAS, Council's decision to adopt CPA 2011-00004 is based on the findings and conclusions found 
in the City of Tigard staff report dated November 20, and the associated record, which are incorporated 
herein by reference and are contained in land-use ftle CPA 2011-00004. 
NO\X', THEREFORE, THE CITY OF TIGARD ORDAINS AS FOLLO\X'S: 
SECTION 1: 
SECTION 2: 
SECTION 3: 
Tigard Comprehensive Plan is amended to include "EXHIBIT A - Significant Tree 
Groves Map, page 461 of Urban Forestry Code Revisions Volume II." 
This ordinance shall be effective March 1, 2013. 
Council adopts the findings recommended by the Planning Commission as described in the 
findings of the staff report dated November 20, 2012. 
ORDINANCE No. 12- 1 D 
Page 3 of 4 
PASSED: Byfll.aj orclj vote of all Council members present after being read by number 
and title only, this ~~ay of. ff~..O , 2012. 
APPROVED: 
;~roved " to form /) .. 
I I y C)_J_A___. 
ci{fAtt;rnt{' 1 
11 I 2-zL12-
Date I I 
ORDINANCE No. 12- / D 
Page 4 of 4 
Chrrg D1-k';en~Iayor """ ..... 
Significant Tree Groves 
City of Tigard 
70 groves 
527 acres 
0 25 0.5 
CITY OF TIGARD, OREGON 
TIGARD CITY COUNCIL 
ORDINANCE N0.12-t/ 
:\N ORDJNANCE TO :\DOPT TJIE NON L:\ND t:Sl ·: ELEMENT'S OF ' l'JH:: l. 'RH:\N H)RL•Sl'RY 
CODE REVISIONS PROJECr BY ,\I\fENDJNC CH.-\PTERS 1.16, 6.01, (dJ2, 7.40, CREAT1N(; 
CIL:\PTERS 8.02, 8.04, 8.0o. 8.08. 8.10, 8.12, 8.14, 8.16, 8.18, AND Dli.LEI'ING CFIAPTERS 9.06 AND 9.08 
OF Till~ 'fiGARO 1\fUNICIPAL CODI·:. AS AMENDED BY TH E TIGARD CITY COUNCIL ON 
--------- --------- --- NOVEMBER 27, 2012. SEE EXHIBIT B ATIACHED. 
\\'HEREi\S, on June 3, 2008 the 'I'iga.rd Ciry Council adopted an t'rban Forest section as part of rhe 
Comprehensive Plan in order m establish broad goals aod policies ro guide the long· t~~rrn 1nanagenu~ nt and 
cnbanccmenr of the urban forest; and 
\\'llERE:\~ , on :\ugusr lfJ, 20!{) the Tigard City Council .readopted the Urban Forest section as part of the 
C:omprchcnsi\T Plan in order ro provide more detailed tindin~s to further support and explain the rationale for 
rhe city\ urban forestry goals and policies; and 
\'\'! !F-:IU ~'"\S. Policy 2.2.11 of the Tit,>ard Comprehensive Plan n·~1uires the city to develop and implemenr a 
citywide Urban Forestry lviasrcr Plan ro guide rhe update of the city's urban fore~tf}' program; and 
\X'HERI~i\S, on Non~mber_ IU. 200Sl, the Tigard City Council adopted Resolution 09 -69 accepting the City of 
Tigard\ L'rban Fore~tn· \[aster Plan; and 
\\ ' IJ[]:Zl~'"\S , the accepted Urban Forestry \1a ~tcr Plan analyzes the past and present conditions of Tigard\ 
Urban Forest, was dcYdopcd through a public process, and recommends a course of action for Tig,ml's urb;tn 
forestry program through 2016; and 
\\'I lERL·: AS. a significant recommendation in rhe l'rban Forestry t\las ter Plan i~ a comprchemiYe evaluarjon of 
the existing Tigard Municipal Code and implementation of non land usc amcndmems such as hazanl tree 
idenr:itication and abatement rec]ui.remenrs, rree pc1111it requi.rcmc:nts and authorization for adm.inisrrativr rules 
in the l.' rban Forestry iVlanual; and 
\VIII:.'_RF~:\S, on Fdwuary 1(l, 201:?., the Tib>ard City Council direcred st;tff to implement the Tigard l\.lunicipal 
Code related recommendations in the l ' rban Forestry f\:laster Plan which include the non land use ::tmendments 
to the Tigard Mwucipal Code through the Urban Fore~tf}' Code ReYisions project: and 
\X' IlER.EAS. a public involn·ment plan was adopted by the city's Committee for Citizen Im' olvemcnt in 2010 
and implt~mented during the course of the t'rb:uJ Forestry Cudc Revisiom project to guide citv staff and 
decision makers; and 
\X'l!ERF:\S, a council appo.inrcd Citizen !\dvi~ory Comminee charged with advising project staff during the 
Urban Forestry Code H.cvisions projecr, met 11 times between June 2010 and September 2011, and reached 
consensm through a ser o f guiding principles on the non land use amendments t:u rhe Tigard Municipal Code; 
and 
\Vl ll ~RE , \S. a Technical .·\d\·isory Committee comprised of city staff and <1 gency representatives was 
co ncurrently cotl\'encd to advise prnject staff on technical a'pects during the Urban Forestry C:odc Revisions 
ORDINANCF N O . 12 - I J 
Page 1 
project , me t 14 tinws berwccn June 201() anJ NoYembc r 20 11 and rea ched C OI1S C1 1SU~ on rhe technical 
fca sibiliry uf the non la nd usc amendments to the Tig:ml f\luni cipal Code; and 
\\ 'llERE.-\S, the public involvement plan included a ciry,vidc open hou;;:e un December 8 , 20 I I , at the 
culmination of t:hc public rtTicw phase and prcJ\·ided an opportunity for the public to rcYicw and comment on 
the proposed ~mt·ndmcnts to the Tigard J\lunicipal Code; and 
\\/ Ill . :IUL\S, the public respo nse a t the citywide o pen ho use on December 8, 2() 11 , w:1 s generally suppurriYe C!f 
the of the non land u~ e amendnwnt s to the Tig::1rd \lumcipal Cnde; ::1nd 
\\ '[I FRL~_-\S , th e non htnd usc amendments u c no t land usc rl'gulatiom, b ut func tion :1s dement~ o f the c11:y\ 
comprehensive urb:1 n fo restry prngra rn ; and 
\\'lll :J\1·::\S, the Tignrd Planning Commissio n rc1·icwcd these non bnd u~e amendments to the Tigard 
f\Iuni cipal C ode a r one worbho p ;md four public hca ri11g~ between .J anuary 2012 and iVlay 2012 whik 
concurrently re1·icwing the land me am c ndmcm s (CP. \ 2() JJ .. ()tJ()04 and D C:\ :21)1 1-00002) o f the Urban 
h.ln.:~ rn· Code Re1·isio ns project; and 
\\i J lERF.\~. u n i\by 7. 2{) 12, the Tigitrd Planning Conuni~~ion unarlimou~l y alkis ed Tigard City Council rh:1t 
the non land usc <t mcndmcn ts to the Tigard i\lunicipal Code arc cun~i:; tcnt with and supp<min: of the l;~nd usc 
amendmcnu.:; :1 nd 
\\ 'Ill JZL. \~ , on the follmving da tes in 20 12: July 2-1, :\ ugu~ t I '~ , ~cprcmbn 11 , O c tober 23, Nuvemlx:r U. 
and Nmcmber 27, the Tigard City Council held a public l1ening to consider the no n Llncl u:;c arncmlrncms to 
the Tigm·d J\Junicipal C ode and the Tiga rd Planning Co nuni ssio n' s advice; and 
\\'[ Jl{RE. \~. ·ri~-,rard City Co uncil fi nd~ it ne cc~sary to dcl a1· implementation o f the l!rbru1 Fore~ trY Code 
RC\·isiom, which include rhc: non land use amendmen t~ to the T igard i\lunicipal C ode, umil i\la rch 1, 201.3, to 
en~ urc :111 orderly adrninistrarj vc trans.itiun tu the new urban fflrcstry rq,.,fl.tlariuns wh1ch includes ensuring th::lt 
the Urban Fore~u-y f\bnua l become~ effcc tin· prio r to the non land use amendments; and 
\\ 'lli ·:REAS, o n N oYcmbcr 27, 2()12. the Tig·ard City Coun ciJ adopted the non land usc amendmmt' by 
m o tion. pursuant to the public hearing and its delibera tion~. to be cffectin~ o n i\!arch l, :20'13. 
NC)W, TIH ;:RL·J·ORE, TilL ern· or: TIC:\RD ORD,\IN~ :\S i {)l.L()\\'S: 
SH~TlON 1: 
SECI'TON 2: 
SECTION .1: 
SECTION 4: 
'I'ig:1rd ,\ [unicipal C ode is amended ro include new text and to amend and rescind cxist:ing tex t 
a ~ ' hown in "EXHIBIT A- on odd numbered pages 3 tltrough 99 of Urban Forestry 
Code Revis ions Volume III ; and 
With the exception o f amendments to Sectio n 8Jl2.(r\0 (Admiru~ tra civc Rules - Urb<tn 
Forestry f\hnualj , this ordinance shall be effccti1·c on March 1. 
:\mcndmcnt~ to Sectio n 13.0:2.030 ( .. \dmini ~t r:1 tin: 1\ulc~ - L'r!Jan Fore~ try ~fanual) shall be 
effectiH' _)() <hys a fter its pa s~age by the council , signMure by the mayor, and posting by the 
citY reco rJcr. 
Council further ;tdopts the cummcnrary in r ·:xhibir A (on c1·cn numbered page~ 2 through <J9) 
as :1dditionallcgi ~brivc in rent fo r the corresponding code amendrncnts. 
ORDl N .\NCF ~0 . 12- I I 
Page 2 
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To: 
From: 
Re: 
D ate: 
City of Tigard 
Memorandum 
Tigard City Council 
't\1arissa Daniel:-;, Associate Planner 
Urban Forestry Codt' Revisions 
NO\·ember 27, 2012 
Exhibit 8 Ordinance Nos. 12-09 
and 12-11 
On November 27, 2012 Council is scheduled to continue the Urban Foresrxy Code Revisions 
public hearing. 'The purpose of rhc meeting is to receive a brief staff report, receive public 
testimony and consider amendments to Planning Commission's recommendation. 
Council Amendments for Consideration 
Staff has prepared se,·cral amendments to Planning Commission's recommended draft based on 
Council direction on October 23 and NoYcmber 13, 2012. 
Amendment 
On 11127/2012, 
City Council 
approved 
amendments 1, 
2, 3, 4 and 6. 
AmendmentS 
was not 
approved. 
l 
2 
,., 
_) 
4 
§ 
6 
Addresses 
Policv Issue I Brief Description 
3 I Differentiates bel:\veen residential and non residcnrjal maintenance 
4 
5 
.., 
I 
+ 
8 
requirements for tree~ planted with de,·clopmem. 
Removes r.ree removal permit requirements for single family 
residential developments. 
Clarifies that hazard trees arc· required ro be removed only in 
response to verified complaints. 
l~nhances the purpose statement in Chapter 18.790 to draw a clear 
link between the details in the Urban Forestry .tvfanual and the 
cwerall purpose of the development code rev.isions. 
Adds the Cflnopy requircfncflt.l to rhe code to drRw a clearer link 
bet'<<eeft the details in the l !rbafl Forem-y ManusJ £tAd the over£111 
"" " ·'·" -. C .1, ... L.-- .. L·· -- ~ --• - ---~. IU.Lpo .. n:; 01 UlC UC\'CJ\Jf711J""Ul C::\.7U'-.: ___ L,....\'~ ._11VJ' "' ' 
Reduces development costs for l\'linor .Land Partitions by not 
requiring an arborisr or landscape architect for partition projects 
that can meet the requirements by planting street trees in open soil 
volumes only. 
At the November 13 meeting, Council asked staff if there are any issues associated with not 
requiring arborists / landscape architeCt$ for 't\.Hnor Land Partidon projects that can meet the tree 
canopy t<:Ljuircmcnts by planting street trees only (,\mcndmcnr 6, Policy IssueR). Jn deciding 
whether ro adupt this amendment, staff offers rhe following considerations: 
l. Reverse Incentive - This amendmem could create a ren:rsc incendve where a property 
owner might rernon: mature trees <l11d plant only street trees to IIHlid costs associated 
with hiring an arbori st/ landscapc architect. 
') Equity - In de\'<:loping the Urban Forestry Code Rnisions, one uf the m ain community 
goals was to address the equity issue in the existing code that places more financial 
burdens on properry owners with mature trees. The canopy approach addresses this issue 
by applying the same requirements rcgardlc~s of the arnount of existing trees. This 
amcndmenr could result in an CLJUity iss ue by exempting owners witho ut trees from 
hiring arboristdland~cape architects, while placing greater rec]u.iremenrs on owners that 
choose to prescrYe mature trees \Vith dcvclo pmenr. 
3. Adjacent trees - i'dinor L:md Partitions invoke the creation of two or three new lo ts in 
exist.ing rc~idcntial neighborhood~ (aka infill den:lopmcnt). Often one of the grcatc~t 
points of conflict with infill de,'elopment is the potential development impacts o n trees 
that arc on an adjacent property but ncar the property line . Invoh·ing a rboris rs / h1nd~c1pc 
architects in the development of I\Jino.r Land Partitions helps ensure trees adjacent to the 
~ire arc protected with accepted methods such as rree protection fencing during 
develo pment. 1 f profcssionah are not required, there is Jcs~ certainty for neighbor~ that 
their trees will be adequately protected . 
~fore inforrnation about each o f the amendments, including the affected code sec rjon s and 
specific amcndmenr~ arc included on page 3. Council will han~ the opportun ity ro accept, reject, 
or rnodif\' these amendments on No,·cmber 27. 
Housekeeping Amendments for Consideration 
f n addition to Council's amendmcnrs, s taff is also recommending a set of housekeeping 
amendmcnrs to the code. These items arc insubstantial to rhc code, and arc described in rnorc 
detail on page 13. For example, .\mendments 8 and 9 correct c.ro~s references inrernal m the 
code. 
::? 
Amendment 1 approved by council on 11/27/2012. Amendment 1 is not part 
of an ordinance nor is it to be codified . This amendment is applicable to 
Volume IV- Urban Forestrv Manual I Administrative Rulesl 
Ame ndments to the Urban Forestry Code Revisions Based on Council Direction 
Amendment 1 (Policy Issue 3): Differentiate between residential and non .residential 
requirements for the maintenance of trees planted with development. Residential trees 
should have a maintenance period of t\vo years or until a .house is sold. Non residential trees 
should have a one year maintenance I.?_e_ri_o_d_. - - - --- --------------1 
Code /Manual Section: Urban Forcsrry l'vlamml Section 11, Part 2 (Urban Forestry Plan 
Implementation ~tamlards- Tree Esrablishment Rctjuircments:) 
,\. Prior to nny ground disrurbance work, the applicant shall provide a tree 
establishment bond for all trees to be planted per rbc approved urban forestry plan. 
'fhc total bond amount;, 
1. Eo.J:.S.J..lbdivisions and minor land panitiom shall be equivalent rn the city's average 
cost to plant and maintain a tree per the applicable sr.andards in the Urban 
Fore~ try Manual for a period of two years after planting multiplied by the total 
number of trees to be planted and maintained;_aru:i 
2. For all other land u.s.c tt.Ylt.\VJ:ypc.:Lshallhe e<.-1uivaknt_ tP lh<:~iJ)(§. _C)y_c.;r;a~re cos.UQ 
pla_p_t an,g_maiqrain a tree per the applicabk.standards in the l J rban_f~or<,::;n.:;: 
Manual for a period of one year aft~r_pla.nting _ _mu!tiplied by th.c....tmal number of 
ttees_tobeplantcd and maintained. 
B. 17ollowing final building inspection or upon acceptance by the city manager or 
designee when there is no final bu.ild.ing inspection, the rree establishment period 
shall immediately begin and continue; for a period of two years. 
1. ln§Jib.diri;;innsi.l.n&l _nartiti,Q,n~.lor...a.pe.riodoft'i\covc.arsur ut1til such rime a§ epcl1 
lot is sold; and 
2. In all _oth.er land use review types. for a..p,eri.oclo.Lone year. 
C. \X'hen the land use review type wiU result in the division of land into multiple lots or 
tracts, there shall be a separate tree establishment period for each resuldng lor or 
tract where trees arc shown to be planted in d1e approved urban forestry plan. 
D. r;·ouo\.ving the t\'>"O year applicable tree establishment period for each lot or tract, the 
bond shall be correspondingly redtiCed based on tree survival following a site 
inspection, documentation of successful tree estA1blishrncnt and/ or replacement 
according to item;i e E and F below, and receipt by the city manager or designee of 
written verification of findings and a signature of approval by the project arborist. 
I •:. For planted open grown trees, successful establishment shall be considered 80 
percent survival of the open grown trees planted on the lot or traer, and replacement 
of 100 percent of the remaining open grown trees planted on the lot or tract that did 
not survive. 
J<. l''or planted srand grown trees, successful establishment shall be considered survival 
of at least 80 percent of the original stand grown trees planted on the lot or tract. 
G. If successful establishment for open grown trees is less than 80 percent for any lot or 
traer, the two year ap.plic.ablc...tree establishment period shall reset for that lot or tract 
and the establishment process for open grown trees described in part 2.B-F above 
shall be repeated until the successful establishment requirement for open grown trees 
3 
Amend men ts to the Urban Forestry Code Revisions Based on Coun ci l Di rection 
1~ mer. 
I I. J f successful establishment for stand grown trees is less than ~0 percent for any lor 
or tract. the £\VO year applic.ahk_rree establishment period shall reset for that lot or 
tract and the e~tablishmen t process tor stand grown trees described in Pan 2.B-l 1 
abo\'e shall be repeated until the ~ucccssful establishrnent requirement for stand 
grown tree:; is met. 
Note: l ~xhibits .\and B to rhe Resolution teYising The Master l"ces and Charges Schedule 
i~ ame nded as follow~ to reflect ch anges in the merhodologv fo r calculating tree 
establishment bonds: ' '' rj _M_a_s-te-r -Fe_e.....:s:;:...a-n<-l -C-ha-rg_e_s_R_e-so- 1-ut-io_n_w_a,_s_n_ot--,1 
considered/adopted by the council on 
Fxhihit :\ - Leg1slat.i\·e In tent for Urban Forestry Fees 
11/27/2012 
Tree Establishmcnt Bond (Planting and Heat~ Early E:::tablishn:wm) 
S489 per 1.5 inch Glliper open grown tree .fu.t_s_ubdjyj.;jons an_<lU.JiPQIJand.,partitiom _.. 
Si..{Lp,<.:LL5.inchcalipcr opetl..ghO_)V_O. tr_rg_fqrJ£ln.s.l LtS.L.t.ITic.lV types orb e LdWU ~1,;1)2_\Jh:.i:;jJJUS 
nnc.Lmino.r11t1.d_parri tions"'"' 
S:)(J7 per 0.5 inch caliper stand grown tree for ~ubdivisions apd.JJ)inw:Jandparti.r.iun.s" r;: 
S.35Lpcr.0..5 inch caliper stam.l_grown tree _(pr_laudJ.Jserevic\vcypes other tban subdh~isicm:i 
and minor land TY''' ';,.;uu~ ~t~': ~ -····--················································ ~ 
>~'The Tree Fsrabbshment Bond for the p lanting and maintenance of a 1.5 inch caliper tree for 
.tlli.:..r.c.q.uit:c..d two years in su l?dixi.~igns and minor lan!.lparti.ti.o.rui is based on a formula that 
combine:; 50"'() of the pubbshed PN\X!JS ,\ w holesale rnedian rree cost estimate to purchase and 
install a 3 inch diameter tree, with the aYerage historical cost for City ofTiga1·d staff ro perform 
two years of maintenance on a 1.5 inch caliper tree. 
":t.'l"be ·rrcc l ~ st:i112li.~b!PGl!J B_ondforrhcplaruine and majtlJC11ill1C..C_D_(a__LSjnchc.aliper tree for 
rhc__r.e.qui.rc.d .uru.:.yc;,tr in l aqsJ.Jls<,;_n:Ykwtr.P~:.:?nJ:hcr thanstt!,dix:isi(>ns ar1d n1in<)r lam:Lparritio11S 
~Jlli.a.fomrulathar combines sor~:o gJJh<,;_ ppJ?Jj~ill:.d PNWlS:\.~:holcsalc rrwslian tree 
ro.s.test:imatc to purch<m;. ~md.iustalLaJjnc.hdia.r:m:1er trc~:; witlub.e ayeragc .hi.stori.cal c<lst_fni: 
(:in:: Q.f TigarcLstafLto p.crform one year _of m~lillt,rmnce on JlJ.,S inch calipJ::Lli:b:b.· 
·n'!The Tree Establishment Bond fo r the planting and maintenance of a tree t\vo feet in height 
or one gallon container si%e (es timated 0.5 inch caliper) fu):..tl1.c,.rc.q~Jjred two .. y.c.ru:s. . .iu 
s,tbdivi_§ions_andmilli2.l: land paniliPDS is bascd on a formula that combines 1 6.6°:(1 of the 
published PNWISA co~t estimate to purchase and insraU a 3 inch caliper tree, \Vith the average 
historical co~t for City of Tigard staff to pcrfonn two years of maintenance on a 0.5 inch caliper 
rree. 
"'·i-* ,,.1 'he · l :nxJ·;~Hll,tliS.hi U£!1' :.Bond.fur thJ,~,plarrting and nlaimcuapJ,;}.;. ( > f.iJ tre ccnv.o .. kCLinheigh t 1 
4 
Amendments to th e Urban Forestry Code Revi sions Based on Council Direction 
·-···--
or.u.ncgallolLcontaim:r_size_(r§rim<IJt<l Q._S incl1 calipcr:Lfut;_thc...rcq1Ji!;~,;gqn~y9~~!1J~,t;td~lJ~iG 
n :viewn:p.csorhetrhan sq)2diy~~ioQ,~ andmi.um: l.a.n<.J .paJ:ti.IiPn~j~hascd.ona.Iorm, Jla tha.t. 
&:.9ml?il.:+f:§ l (l·V1t~Lthr.;.~.lished.P.N\'V'lS;\ mst es titpare .. topun,:basc HJJJLitJA~lt.a..Jj,n~h 
calipe.r ... tt:.e.e .•.. \vith .. the.ave.l;!J.gs:_bi§.tQJj_\;.£1.1.. \;Q;:<l .... fQJ:Gill'-oLI:ig;!l,t:}:l sraff .. to ... per.fo roJ. ... <mr.;.._y!;:l.lLQf 
Pl<:!i.+Hgnml~_GQ~(.t.'iim:h_.c;Jlip_er __ trce. 
Fxhibit B- Amended i\l astcr 1-'ces and Charges Schedule 
Community f)evclopmcm - Miscellaneous Development 
lJ.r.b!.l!l_Fores t;;ry 
'T'rec Establlshmcnr Bond (Planting & 3 Year IV!aintemmce Elltb·J::§tabll,.·ibJpent) 
1. 5" Caliper Street orOpen $489 pcr tree 3/ 1/ 20 13 
G rown Tree in Subdivi§iQP§ 
gxJ\Jioml.ansJ .. P(u;titi.~).JlS 
l.S'' Cali_lli:r. Str~etQLQP,~A 
GNlY.!1Tn·ejuLand Us_e 
Revit:w · [ypes nthe.uh~m ~·--·· --· .:: .... _..................... -··---·--· .. ·-· 
S.u.b_div.i:;ions .... or .. ~.:fino.tJ .. ,and 
Eattiris).us 
2' in Height or 1 Gallon 
Con tainc t~ i\'hnim um Stand 
Grown 'free i~,11h.d.ivisions 
pr ... l\linor Lan d .. Paniti~ 
z~ _i.nl;:kj.or_l .. .Gallon 
Cmltait1e.r_i.\1inirru.tm .. ~Jan9 
G rmvn.Trccjn.Land. LJ .. ~5::. 
1\:GYlS:l'{ ..  !.YP.~..S o.l&LthmJ 
Subdivisions <) r..~JiJJ<JIJ&nd 
Partirjops 
·····-----··-·----·-·-·-·······-···---··-·--···-··--- ---------
S441 pertt:.G,~ J!J/ 4013 
$367 per tree 3/ 1/ 2013 
S.~5Lperr.rc.c 3/ l L201J 
) 
Amendment No. 2 approved by council on 
11/27/2012 -Ordinance No. 12-11 
Amendments to the Urban Forestry Code Revi sions Based on Council Direction 
Amendment 2 (Policy Issue 4): Do not reyuire tree remoYal permits for single family 
residential develonments. Aonlies w Ordinance No. 12-11 
Code/ Manual Section: Tiga rd ~Iunicipal Code Chapter 8.12 ( free s that Wl'te Ret]uircd 
with DeHlopment) 
8.12.010 Purpose 
The purpose of this chapter is to establish standards and proced ures for the 
maintenance, removal and replacement of trees that were rel.Juired with higb_dcm;i:cy 
_rqi~l!:~!J:1ia1a_miJlDP,J~'~icjq;ujaJ development to maintain their em·ironmcnral, aesthetic, ::;ocial 
and econo mic benefits afte r rhc dcH~Iopment proces~ is complete. 
8. 12.02() (;eneral PrO\·isio ns 
. \. The proYisions of this chapter do not apply unle~•s there i:• sub:<~ 
evidence that one of the following ~•itutttion:• exi:;u: ls:J. rcsidcnxialckY_dopmcnts_in tb\:_ R~ 1.. 
l.tZ.J\ - 1:2..1~ -1,5 .. R:L aud.R:J2 disrriclli. 
It. _____ ]:h¢: px_~n·i~_iru~chaptcr.do_.ap.ply when therc_ i~?Pll~lantial cyidcJ.Kc.that 
o.nc .of..thucllo.vving :-:ituarions <:_;}j_srs: 
1. I <:xcept for those d<;:.rrloprocnts listed in tU2.0.2LL~\...ahovc frrce s were 
planted or prcscrn:d under a reguircmcnt found in Title 18 or found in a hmd u sc pennir; 
and 
2. Trees \\TtG required as rcpbcemcms fm trees originally rccjuircd under 
!).1 2.020.:-\-J}.'l above. 
B~. The cit-y manager or de signee shal l urili7.e all aY:J. ibblc land usc pcrmir record s 
and data when detcrm..ining whether a tree is subject tu the pro,·isions of this chapter. 
Note: The corresponding commentary for the code amendments is arncnded as follows to 
provide a record of legislative intent: 
Chapter 8.12 TRI ~r:s Tf-L\T \X'ERE REQUJRED \\'l'Ill DEV12LOPI\fENT 
Chapter 8.12 establishes the framework for permitting decisions for u·ccs that were n:<.Juired 
to be planted or preserved by a land u~e pl'rmit for hifh dc.n.siry resideqtiaLan.d n.on 
rcsidc11tial dcvdopmc_ntwhcn the removal is nor a~sociated with an actiYc land u::;e permit. 
The intent of the legislative amendment~ in Chapter 8.12 is to supersede the planting and 
preservation rcyuircmenrs for trees that were required by prior land usc decisio n s. Thi:-; 
incluc~c s trees that arc reco rded ~1 s preserved on propcrry deed s as a result of pnst land usc 
(, 
Amendments to the Urban Forestry Code Revisions Based on Council Direction 
r- dcci~i~~;;:-· IIowcYCr, fo r th ~·sc deed restricted trees, applicants (and ;;ot the cit}~Y~vill be 
: solely responsible for identifying and removing any applicable deed restrictions. 'fhe city \\·i ll I provide any signatures necessary to facilitate the removal of deed restrictions for trees 
I
I :::::.·:::~:. ;==::::';,~2dcvelppmwlli~d 
nK~ditlmdcn.s.iry r.c.sldcn.ti.al devcl<){liD.rnri.;:;l?fGJUS.rJbr u:wugr~J>f tl'tG~PJ:(JP~J.cics._arcJikdr 
IPJ1lill.nta.in .. an~lpr~~<,: tL.c_trc~s....ll.l the.scJoca.rio.ns. ... rcgard.lc.s.s ... D£ .. codc~cmGn~ 
clrc.Llms.tanc_cs ... \vh.c.r.<;.' __ mY.Ucrs_,d.ccidc .... t.P .... 1:r11JQ1'.C .... hca.l.rbyt.~~~h.S. .. rGq1L.irGd ,~liJ:l dG:h~lgpmcnL.an: 
}.: .~ncqs:::d ..... lP ... h.G ...  !Jf:;gligi4k~¥h!,;P,J;,Qt:;IJP~J,rG9,}yj_tlL.Dgard'.s .... o.\:crall urhan ... fo.n..~ .s.t. 
Hilln·wr, it is important to note that the -12\ml..Ut reqtJirernhfltS fq;:=,~!:.t~~~tf!J1<.l l\1~J.iianTre.c.s. 
.(Gb.~ll2.t}: .t ... 8.Q8) .... :n:~.G8 ... in .... Sc.n.~i. tiY<:: .. LfiJ:l!,lL(.ti,JQ)J'rcc.s .... rJmt ... .\vcre .... J~lann.:"(WJ~Jng __ d.l.~.J)rban 
.Eorts.trv .. Eund .. (8..1.4) .and.l:kritagc.,Trg_r_s __ (8,l(l) .... \Y.~.?\tl.d ... \PP.ti®~~o._.a!Jpl:v ... ev.tn .. ll.Ll<·>w anq 
mcdiurn....d.emiry ... rcsidc.ntia.Ldevdop.n:lent._ln_ aclditic>q,j[§igJ:Jifi<;:aUI,JJ:,b~g~~ arcprtstnrc.d 
iuJ.mv._and .. _lne_cli~~-{;nsitY_IG.~ ici.b:rt..ti.n.L.dh:r_<::_lgpm_<;rJt,_:thc__slgnific~J.tlL.tr.e_e_g11>I£Jlrrs..s:.rnuign 
f.~l±.ir.e~JJ.ts.in_sc.c.tionJ8.790.Q5Q.D \vould ... .:m.p_h.:, 
8.12.010 Purpose 
The puq)ose srarcment explains rhat the chapter establishes standards and procedures for 
rxees tha r were required \vith bigb _cl,~P5it)"J;,G~i.d~1.:lUf.llandnonrcsidcntia.Ldevelopment to 
maintain their benefits afrcr the development process is complete. 
8.12.020 General Pt:o\'isions 
'I'hc provisions of Chapter 8.:12 apply to tret~s reL]uired to be planted or preserved illJligb, 
&itn,sit:yrc~id<::Ati~bJ:l<J,not_J,rcsidcntiaLdcvdopmcntby a land use permit and tree~ rhat are 
required as replacemcnrs for said trees. 
]]1h JUPYi5iP!1~mg f Cj1 aprc.r_8.12 clo notapplv.m.tiL.l:c..sidc;ntial de\' d .Qplnent.s.....i.ll rhc.J\.:1. R:.Z,J\.: 
1 .. 5 •.. R:4 .. 5 •... B..:I,,aJld ... R~.l2_ .. di~t:ris:J~ ?i.! .~ .s:.~_ ... ! .h~-~s: are._tbc_prima_Q'J<u;:.atiomLQ.[ :;.i.n,glb famil}; 
. 1 1'h . . . f II "d . l d · l . II rC.Sl.C .e.ncc.s. . . .. C .. prm~l.~Will . S,P ... CCI-J XG~L~nna, ~(;'yt;: _Q.pPJ.Cll.ts. __ $~()! t Q. exemru J)_C.:>n 
£,~Q~J~!inldeY~lupments .such as .schouls_in;:.s:sidc..!ltial .distri.c.ts....fmnLthe..J:.eg.J..ll.r.emc.ms., 
H. 12.030 Maintenance of Trees T'hat \v'ere Required With Development 
Trees that were required to be planted or preserved inhighdQl:ti:..Q:_ l~~j.si~lliiaL.andnon 
r.e..sjcib~!Jtin.Ldcys;loQIDent by a land use permit are required m be maintained per tree care 
industry sr.andards. 
H. 12.040 Removal of Trees That Were Required With Development 
Amendments to the Urban Forestry Code Revisions Based on Council Direction 
Permits obtained through the City ~Ianagcr Decision l\laking Procedures or the City Board 
or Committee Dcctsion [\'faking Procedures arc requi red to rcmon~ trees reguircd to be 
planted or prescn·cd inhigh~l<:n§i...t);JJ;§id<:.ntiaLandJlQtl[<.:sidc.mi.aLd,G,):J,:,lppmc.llt,by a land 
use permit. 
8 
Amendment No. 3 approved by council on 
11/27/2012- Ordinance No. 12-11 
Amendments to the Urban Forestry Code Revisions Based on Council Direction 
Amendment 3 (Policy Issue 5): Clarify that hazard trees are required to be removed only 
in response to verified complaints. 
Code/Manual Section: Tigard i\funicipal Code Section 8.06.020 (Hazard 'frees Prohibited) 
t\. Hazard trees that_arc_ycrific..cl.thmu!)'h the Hazard Tree EvahlaJ.jqpa,od 
,L.\.batemeor Procedure in Section 1 £1Lthc l}Ib£1nfQJ{;§~~J£1nual are prohibited within the 
City ofTigard . 
B. ,\ny hazard tree owner or re~ponsibk party idcntificdthm .. ugh tb}.;J:lazar9 
lli .. cJiY..ahl.a .. tiDJLand .. .A.batemeot Proct·<lure i11 Scs:tio1119flh.~Ud)HQJ''m:b~tl:Y Man.ualshall 
be required to complete hazard tree abatement. 
C. Failure of a hazard tree owner or responsible party id .. bJUified thruugh..Jhc 
I::Iaz .. ar..d 'l"re_~~Ev<tlP.£1JiPHJlQQJ\l?al~nJS.:J1t J>rocedute...in...S.cctioo 1 of rhe l Jrban Forcstn; 
Man.ualto complete hazard tree abatement i:; a nuisance under Chapter 6.02 and subject to 
penalties under Chapter 1.16. 
Note: 'fhe corresponding commentary for the code amendments is amended as follows to 
provide a record of legislative intent: 
Chapter 8.06 IL\Zl\RD 'J'REES 
The hazard trees chapter creates a framework for addressing hazard trees. 
The guiding principles for Hazard Trees are in Volume .J. :l of the. legislative adoption 
package for the Urban Forestry Code Revisions. These guiding principles represent rhe 
consen~us view of the citizen advisory committee that advised staff on the Urban r:ore~try 
Code Revisions. 
8.06.020 General Provisions 
Hazard 1rees (defined in Chapter 8.02) that arc veritk>..l through the Ha.z.an.i..1l:.c.c .. Evaluation 
and :\batemcnr Procedure in Ssctioa.J _D.Lthe U.rbnnJ::ore~m ivlanual are prohibited in 
Tigard. The reasonJqr §JJCcifyinv thaub.r __ prohib.i.tion applies only,jQJ)azard trees vcrific.d 
.tb.mugluhe_p.ru_c .. cd.u.r.c...in .. .the UrhanJ"pre~tryJYlarmal is ro ayojd tbe .. 11qre scale remonl of 
t:rt~~§,JJ}LJ.:U:QP.eny owners th.a.t...lvo..uld othenvisc be unrki:W:\Y.hctbbl9JJJOt their_.s .. pcciflc ... ..trc.cs 
arc...bazards. The definition of ha1~ard tree incm·porates by reference the jitC1~9chu;~jn_th.c 
llib..'ll1£o.re..~.tq' Manual includes an .s;Y_.aluation by a tree .. risk asscs~or.oLth.c...probability of 
failure, size of defective part and target a.rea .b.c..(QJ .. ~~ .. s.kterminiov :\Ynerhe.r_a.rrce is a hazard. 
t) 
Amendment No. 4 approved by council on 
11 /27/2012- Ordinance No. 12-09 
Amendments to the Urban Forestry Code Revisions Based on Council Direction 
Amendment 4 (Policy Issue 7): Enhance purpose statement in Chapter 18.790 to dnnv a 
clca.rer link between the details in the Urban Foresa-y }'vlanuaJ and the overaLl purpose of the 
development code revisions. 
Code/Manual Section: Tigard DcYelopment Code ~cction 18.7lJ0.010 (Purpose) 
Purpose. The purpose of thi s chapter is to implement th e City's urban forestry goals 
:uriculated in the Comprehensive Plan as rccommcnJcd by the Urban Forcsrry l\Jaster Plan: 
b;.: cstabli.:illing; 
I ,,L___ Tre..e~ c.arl.op.L ..coY.t'.r .. r.c .. (.Jl.Urcmc.ru:dw:...nc W_QG\:J.:h~P01&11J n;:ganJJc ss ( >Lrhe 
amuunLof existing trees on si te; 
U. ·····-······· ..... i.)lJGXQ<.HiYG .. ~"JQ.~mc_e:t.ingu.cc .. c.anop_.L.cmTI.J:ey_y_\.r}.;.!IlG_oJ::L:.Yl!s; .. o ..... ~.SJ~!b:_alenr 
cm:ironmcnr.a.Ltum;t.ions...or valttcs art;J?Xm:jg t~st 
< :. l :lexiblc an_~_ jn~~rntiY&: J?O.:SG9 n:SJtU.rc.:mc.nLS_tu. facilitate the planring;J.Jf Jgx..vs 
.:U <U\.:!l~J[£_C.~.J.1UCLt~rc.suxarion ufJ.:x.isting _ _tn:_~ <tnd sig nj fie an LJl<:G_J';r~ J\' ~ 
J2. J\G~llJiXGPJ<;llJ;; tbaLC.O>ii.U:.:..suc.ccssfuLlmplcmrut.at.ion c>f url)an _fm:_~,;.strv plan.s. 
du.ri.ng=amLaftc..L..:illi: __ dt:T e I< >p me o t; an J 
E. __ ...:\. _pr.o.c.c..:ili t<>r modifyiog __ urbanJr?JGSJX): !21a_ns to _addr.c.sschangc..s tl1at occur 
durine- the development process[ 
Note: The corresponding commentary for the code amendment~ is amended as folkl\\-s to 
proyiJc a record of kgislarivc intent: 
lit790.010 Purpose 
The purpose ha~• been .;impl:i-tiet:l-ffl .s..tat! .. :lllcnr cross reference~ the Comprehensiv e Plan and 
Urban h>restry Master Plan. Both documents provide the derailed policy basis for the 
extensive revisions ro Chapter 1 H.790. Examples of the ~tcrpr_m:isions __ thatimplcrnent 
rht:.C.izy's urban forestry gual~_ llt.:hJ.?.IQ'jde_q to gll:e....u..s.crs of thc.J:ude a b_s.?.UC.Lmld<;rstanding 
of the m·qaJlpJ.I£PP?.?h._9L.r;1w .~hap_c.r, 
'-· 
J(l 
Amendment No.5 not approved by council on 11/27/2012. 
This language will not be codified in 18.790.030 
Amendments to the Urban Forestry Code Revisions Based on Council Direction 
Amendment 5 (Policy Issue 7): Add d1e canopy requirements .in the code to draw a dearer 
link between the details in the Urban Forestry Manual and the overall purpose of the 
develq_J?.tncnt code revisions. 
Code/Manual Section: Tiga rd Development Code Section 18.790.030 (Urban Forestry 
Plan Requircmcn ts) 
,\. Urban f-orestry Plan Requirements. ;-\n urban forestry plan shall demonstreJC. 
.rhc . .f.illl.uwing..clfc.cti..Yctre.e_c.anopy cover requirements will bc__tp<;J in the fpl_lgwing districts: 
District 
1-----'~~~~~~~~--+------·--------·- - --------------1 
:1f)<{~u. fm;_ overall sire and excepr fQI__.<>~bqql§ 
__ }-~~{i.!.Jor ... c.achlm .. g;:.tract -+~~~~~tL---=--=---=--=--=-=-=--=-::-:=--:--:-:-=-----:-::-:-:-:::--::---1 
3 3°;o for QY.~taJJ §_tH!. R-1 2 H. -25 R-40, Cd~:J.. C-.C, C-G .C:E, MUE .. MJJE:l l\1! JI;:-z. 
1\:lliC. . .MliR .. amLI::E.districts exc~m:Jor .§_cl}oo)§ (18.1 30.05.0{1)) 
2 5%tlru_os..ctalL.site 
;\n urban for~st!J;' plan _sba1L 
.Mll=..C.BD.MUCLJ:l ... and .. I-H districts, and fgr sJ;b_pnl_~ 
(18.130.050(.!)l_in all fiisttjs;t:i 
1. Be coordinated and approYed by a landscape architect (tlw project landscape 
architect) or a person possessing dual certifications as a certified arbo.rist and cerrified rree 
risk assessor (the project arborist); 
Note: The corresponding comrncnrary for the code amendments is amended as follows to 
provide a record of legislative intent: 
18.790.030 Urban I''orestry Plan Requirements 
This section is renamed ro Urban Forestry Plan Requirements., 
T'he c ffectiy_}.; tt.C..~ . hfltNP.X.. c<1yer rt;s]uir.emcnts..ar.dncludcdjJJdl~ ~,;g~)£J9 .. P.mYidg usc.r.s . .oJ 
.thc_.c.o_ck_.adc.are.rundc.rs.tanding of the overall puq25J§C oLthe_U.rhan .. Ew:c.s.r.ry Ehm 
l).equircmenrs without rcquirio.g,Jhgm..,t.Q ,n:#gd:m.BJgb the details..oLthc Urban Forest.Q: 
hf.anuaLJJJc_cfTcctiv e rree canopy c n:n;rJJ'.H!:'in;nJ.R!Jl;_s wc.r.e..cx.tcnsively.J:c.s.tc.d .duri 11g the 
peer review phase o( tbe.llrben forcs.u.-y._.C.o.dcJlcvis ioos and \X,Crc fognd to be achie.vabk 
thmug!Lplantinw-_and presenjng _3Il _amnuot ofuee canopy rbat is acceptable to the 
community. 'l'hc.peer_.rcYk:\v. . .tesults can bt~ fmu;gJjnY._olume II, .and.unor.c. ... dc.tailt:.d 
description of the can~ndard.s.canhefo.un.djn Volume V ,nf rhc_legislad_ye adoption 
p.ac.kafe for the; UrbanJ.~:.Or.c..stcy_Code Rr,xjsiorJ;:;, 
11 
I 
Amendment No. 6 approved by council on 
11/27/2012- Ordinance No. 12-09 
Amendments to the Urban Forestry Code Revisions Based on Council Direction 
Amendment 6 (Policy Issue 8): Reduce development costs for M.inor Land Partitions by 
not requiring arborists or landscape architects for partition projects that can meet the 
requirements by p lanting sr.reet trees in open soil Yolumes onlv. 
Code/Manual Section: Tigard Dc,·elopmcnt Code ~cction 18.7<J0.():;(1.r\ (U rban l'orc ~ r.ry 
Plan Rel]uircmcnt~) 
... An urban forc~try plan shall: 
1. Be coordinated and approved by a landscape architect (rhe project landscape 
architect) or a perso n pos~e~sing dual certifications a~ a certified ;uborist and certified tree 
risk assessor (the project arborist)....Q&&;J2t for ;\jinw:J {:;md _ l?axt:i.tinn~ _lbM _~;0n daiillnsuarc 
~, ~th cffcctiye tree CallQPtCO\'Cr i\UJ ~pij_ YS~hJJJ1~J;S:qqjrnn_~ptS _b_yplanting .stn:C1 
Jrcrs..il.U2.p.c11~il n.>lumc~Jtl):; 
Note: The corresponding commcnrary for the code amendments is amended as follows to 
prcwidc ~1 record of lcgislati\·e intent: 
18. 7Sl0.030 Urban r:orestry P lan Rc<..JUircments 
Urban forestry plans arc recp.1ired to be dcYclnped by a landscape architect ur a person 
certified as both an arborist and tree risk as~essor. I\lany arborists arc dual certified, and 
adding the new requirernent for tree risk assessment will help ensure safe conditions during 
and after construction. J ,andscapc architects often work closely with arborists when 
dc\·eloping urban forestry plans. so the option of allowing landscape architects to sign off on 
the plans has been added to reduce costs by eliminating the need for hiring t\vo urban 
forestrY consultants. 
,\rbori§t;i •mdJnnd~~ap~: !Jn::hilC~J~ -~G .IJQ.h~t,~,bli.rc.d.Jo.r .. MincuJ ,and Partitions if rhc _s:fic~Jir~; 
!J(C ~f!IlQJLX ~P \'_CCilP<;Lsoil ,·r>lumc_rcqJ.rircmc.ms.c.an_be met b.)·_plancinv srrq~It:rcr;;;inqp,~ 
.so.iLv.o.l.um.c.s. . .onlr~ -:Lh.c._ purpose <>f the cxemprignj$J_Q n;duc.c..msrs..k1r...small :;calc rcsideotia1 
project;;t'V:hcnz_ r.lJ.s: _n;mlin~S:Ll.hHLPf specialized profc:;siooal \:_"Qpcrtisc is limitc.g, 
1:.: 
Housekeeping Amendments 1-13 approved by council on 11/2712012 
Ordinance No. 12-09 and Ordinance No. 12·11 
Housekeeping Amendments to the Urban Forestry Code Revisions 
Amendment 1: l~-;;-~ure consistency in the title of Chapter 8.02. Applies to Ordinance No. 
12-11 
Code/ Manual Section: Tigard Municipal Code Chapter 8.02 (Definitions, Penalties and 
Administrative Rules) 
J.]([;).RIJ NUNICIUL.CQD F~ 
Title 8 
I URBAN FORESTRY 
! 
I Chapters: lHl2 D EFINITIONS, PENi\LTJF~S AND r\ Df\liNISTRYITVE RlJJ.ES 
8.04 TREE PEIUvliT PROCEDURES 
8.06 llAZ.ARD TRF<] ~S 
8.08 STREET AND MEDIAN TREES 
8.10 TREES IN SENSITIVI~ LANDS 
8.12 'fREES TH.ATWERE REQUIRED wrrH D Ev1::LOPI\.fENT 
8.14 TREES THAT W ERE PLANTE D USING THE URBAN FORESTRY Ft:ND 
8.16 HERITAGJ<: TRI~ES 
Chapter 8.02 DEFINITIONS, PEN1\LTlES AND i\ DMINlSTRAl'lVE RULES 
.--------------------------------··-······---·--·-
Amendment 2: Correct a cross reference in Section 8.02.020.C (Defining Words). Applies 
to Ordinance No. 12-11 
i Code /Manual Section: Tigard :Municipal Code Section 8.02.020 (General Provisions) 
C. Defining Words. Words used in this title and the Urban Forestry Manual have their 
norrnal dictionarv meaning unless they are listed in Section 8.02.050. Words listed in Section 
,/ L ' 
8.02.04J0 have the specific meaning stated, unless the context clearly indicates another 
meantng. 
••••••-Rn••nnhn---••·-·" 
13 
Housekeeping Amendments to the Urba n Forestry Code Revisions 
Amendment 3: Ensure the tenn "Diameter Rt breast height (DBH)" is placed in 
alphabetical order in Section 8.02.050 (Definition of Specific Words). Applies to 
Ordinance No. 12-11 
Code/Manual Section: Tigard ;\f unicipal Code ~ection 8.02.050 (Definition of Specific 
Words) 
~ti. " Driplinc"- The ou ter limit of a tree canopy projected to the ground . 
HG. " Diameter at breast height (DBl-I)"- The an~ragc diamcrcr of the trunk of n tree 
measured 4 1/ 2 feet above mean ground Jc,·cJ. .. 
lnutc: tT,·crsc orclcrt()Ehlcctcrtl1sin alphabetical o rdcrJ 
1-l 
Housekeeping Amendments to the Urban Forestry Code Revisions 
Amendmen t 4: The Pacific Northwest Chapter of the International Society of 
,-\rboriculture (PNWIS1\ ) developed d1e current tree risk assessment methodology and 
certification program. Due to the success of the program, the International Society of 
Arboriculture (ISA) is in the process o f adopting the program internationally. However, in 
the process of adopting the regional program for international users, d1e ISA expects to 
modify some of its aspects. 
Terry filanagan, local arborisr., tree risk instructor and President of the ISA, has advised on 
how to address the expected modifications in light of the pending adoption of the Urban 
Forestry Code Revisions. Specifically, he has advised generalizing d1e term "certified tree risk 
" " ' k " b f . . d . . I . fi . assessor to tree n s . assessor ecause o . antiCipate revtstons to t 1e certucatton process, 
and replacing reference to "PNWISA" with "ISA" to reflect the international scope of the 
program. Finally, he has advised retaining rhe numerical rating system since that is the 
currendy adopted standard. If the nurnerical system is .revised in the future, it may be 
replaced with the updated system. 
The following amendments implement these recommendations. Applies to Ordinance 
No. 12-09 and 12-11. Ordinance No. 12-09 affects Title 18 also known as the 
Community Development Code while Ordinance No. 12-11 covers affected chapters 
in the Tigard Municipal Code consisting of active and reserved Titles 1-17. 
Code /Manual Section: TigarJ ~v1unicipal Code Section 8.02.050 (Definition of Specific 
\\lords) 
D . "Ceftified tJ ree risk assessor'' - :\n indi,-idual cerrjfieJ deemed qual.ific.d by 
the I nternatjonal Society of "\rboriculturc to conduct tree risk assessments. 
!note: re-lettering of the section is required to place terms in alphabetical order] 
Code / M anual Section: Tigard Municipal Code Section 8.02.050.1 (llnard Tree Related 
Definitions) 
2. ''l-lazard tree - Any r.rec or tree part that has been or could be determined by an 
independent cerrjtied tree risk assessor to constirute a high level hazard requiring hazard tree 
abatement wirh an overall minimum risk rating of 8 for trees or tree parts up to 4 inch DBH, 
9 for trees or tree pans greater than 4 inch and up to 20 inch DBti, or 10 for trees or tree 
parts greater than 20 inch DBH using the moHt cutrcm version of the tree risk assessment 
methodology developed by rhe lmemational Society· of .\rboriculrute in :\p . pen_di~ . I pf the; 
Utban..Eme.strv ... M.anual. 
3. "}Iazard tree abatement" - The process of reducing or eliminating a hazard to an 
ovcn1ll risk rating of less rhan 8 for tree~ or tn~ c parts up to 4 inch DBH, 9 for trees or tree 
pan s greater than 4 inch and up to 20 inch DBH, or 10 for trees or tree parts greater than 20 
I ) 
Housekeeping Amendme n ts to the Urban Forestry Code Revisions 
r·····---······---······------···----·-·--·-·····--······-- ----··· ..... . ····--·······-
i inch D BH using the mu:;t eunent v er~•ion of the tree risk assessment methodology 
I 
deYelopcd by rhe lmernatifJnal Society of .hbtwi:ettlt-ttt:e jg, ; \pp<:;qdi:x. .. Lu_f_thc. .. Urh.an.Eur<;.§!IY 
. Manual through pruning, tree removal or other means in a manner that c 
' applicable rules and regulations. 
Code /Manual Section: Tigard Development Code Chapter 18.115 (List of Terms) 
Certified Tree Risk Assessor 
· Sec Tree F<.c!ated Dejinition.r 
'l'rcc Related Definition~ 
• Cal.iper 
• Cerriti.ed .. \rborist 
• Cen.:ified Tree .Risk Assessor 
!note: re-ordering of the secrjon is nx1wred to place terms in alphabetical order] 
I
! Code / M anual Section: Tigard Development Code Section 18.120.030.:\.170 (I'ree-rclatcd 
, detinitions) 
! I ... I c. "Cenjfied Tree Ri~k i\ ss e s ~or"- An indi\'idual certified ~mc.dq.u.alifled bv the 
1 
1nrcrnarionnl Society uf .,\rboriculture to conduct tree risk as:->essmenrs. 
I ~: "Hazard Tree" - .. :\ny tree or tree part that has been or could be determined by an 
i independent certified tree risk assessor to constitute a high level hazard rctjuiring hazard tTce 
1
1. abatement w:ith an <Werall n1inimum risk raring of 8 for trees or tree pans up to 4 inch DB.H, 
9 for trees o r tree pans greater than 4 inch and up to 20 inch DBH, or 10 for trees or tree 
1 parts greater than 20 inch l)BH using the mo,•t current \'et'8ion of the tree risk assessment 
methodology J.e.velopcd by the lntemational Society of .\rbmiculrure iu..A.ppcndiuoLtl1,1,; 
l,}, J;}Jan Ew;~ .su:v .~1<;tn.ual. 
h. "Hazard Tree .Abatement" - T he procc~s of reducing o r eliminating a hazard to an 
overall risk raring of less than 8 for trees or tTee parts up to 4 inch DBH, 9 for trees or tree 
pans t,rrcater than 4 inch and up to 20 inch DB H, or 10 for trees or tree parts greater than 20 
inch L)BJI using rhe moA cuucnt ver:1ion of rhe tree risk assessment methodoloo-v 
' b) 
t!eTetoped by the International Society of . \rboriculture illAPP£1J~Iix Lnfthc._l l.rhanForesrxv 
.;\!anval through pruning, tree removal or other means in a manner that cornp lic:> with all 
applicable rules and regulations. 
1 
!note: re-ordering of the section is .required r:o place t.erms in alphabetical order] 
Code/Ma nual Section: Ti Yard Devclo )ment Code Section 1S.790.030 Urban ForestT ' 
1(, 
Housekeeping Amendments to the Urban Forestry Code Revisions 
r-·--·············· ·--········-·-· 
! Plan Ret1uirements) 
.:\. Urban Forestry Plan Rcc1uirement s. :\n urban foresu;· plan shall: 
1. Be coordinated and appnn-ed by a landscape architect (the project 
landscape architect) or a person po,,~le8sing dual certifications a:l rha.ti~_hmb a certified 
arborist and cer6fied tTee tisk assessor (the project arborist); 
Code/ Manual Section: Urban Forestry ;\1anual Section 1 (Hazard Tree Evaluation and 
Abatement Procedure) 
Part 1. Informal Reconciliation 
... The clain1ant is encouraged to support their claim with documentation by a ce.rtified tree 
risk assessor ... 
Part 2. Formal Reconciliation 
... Within scn:n calendar days of receipt of all the required application materials, the city shall 
. gain access to the rcspondenr's property either Yoluntarily or with a warrant pursuant to 
I Chapter 1.16 o f the Tigard \Junicipal Code, cond uct a tTee risk assessment by a certified tree 
! risk assessor using the most current versio n of the tree risk assessment methodology 
I developed by the International Society of Arbmiculrure !Il~Qptndi.\..LoLtbe UrbarJEqn:st.n 
i t:lanual, determine if the defini6on of hazard tree in Tigard Municipal Code C haprer H.02 
I 
I 
has bee_ n met and, if necessary, prescribe hazard tree abatement as defined in '['igard 
l\Junicipal Code Chapter 8.02 ... 
I 
Code/Manual Section: Urban Forestry :VIanual Section 10 (U rban Forestry Plan 
Srandards) 
Part 3. Urban Forestry Plan- Supplemental Report Requirements: 
C. T he name, address, telephone number, email address; f!J.l~i lSA certified arborisr 
number and PN\\' IS .\ certified tree r i ~• l< as:'ies;.or number of the project arboris t or stamp 
and registration number of the project landscape architect. 
Code/Manual Section: Urban l'orestry :\hnual Appendix 1 (I'ree Risk :\ ssessrncnr r;·onn) 
Date of I·: valuation: 
Certified 'Tree Risk :\ssessor: 
Certificate Number: 
- ---···-·--······---·······-···-· 
IS.A Number: 
1-
Housekeeping Amend ments to the Urban Forestry Code Revisions 
Ccrrificd Tree Risk :\sscssor Signarurc:: __________________ _ _ 
Code/Manual Section: Urban l ·'orcstry .\lanual :\ppcndix 9 (Urban l'<m:srry Plan-
Supplcmenral Report Example Template) 
General Information 
ISA Certified :\rborist No.: 
1S.\ Certified Tree Ri:d,-A·~~·-N·tt·.--; 
Note: The corresponding commenrary for rhc code amendments is amended as follo\vs to 
proYidc a record of lcgi:;)atin· intent: 
1 K.120.030 l\Icaning of SpecifiC \X/ords and Terms 
Cncifice4Trcc risk assessor: This term clarifies thar certified tree ri sk assessors arc Eeffitied 
indivicluals.~.:kemccLqualificd by the International Society of :\ rboriculrure (lS; \}Jq cO!J!.:l\JcJ 
trG,· .... 1 :is.~ ... il$?.~~ ~sl:J)~-~-~) .~.$ .· .... ·I'b.<: ... l)a.(i.fi.c .... NoxJJ.~:.<;:.;u; ... C.hal:?tGX .. Gi.,tbgJJ:J,~<;:tll!11io.naL.S.Ocicn: .. ill 
... ~rbn.riculmu:JJ,?NWJS :\}dcyelqpG_dtJJGc\JrrcnlJI~'rXi~ka§t'~'~SJP~lt,mgtbo~h:>logvand 
.I::,S:1;Jifigtis1.D .. PW.g£mJ1,~ DJ.lf: _t(L.the_sJ.Kccs::; .... of .. tllc .  program •... tlJ.c ... lS..:\ .. i~.in__tl:~Jq:::-_§ __ nf 
ad.qp.ting .. tll<;J:U:Q~_ll_i_n rem a ri<·>n <J ljy, ____ HP\YGY<.;I •.. .ill .. thh .... Pl.:P&:.\,';S.§ ... nf iWo.p.tit1g.Jllc. .. p.r!2gtmnl.ill: 
inreruatiilllall,~~'\.~f;;~l~~W,.tllQ.Qj_.fy"-'iQJJ1<; .Qfit~ asj.2~ht::;, One .anticipated 
n1Qdifica tion . i~ r~.: placcm en t o Lthe tcun .. ~~-w=ni fi~:d. tr~~ ~~ xi? k.a~~t§§(U: '' with \h<.; tgno ·,:Hualiflcd 
JI<.;t.; ri~JS)!~_$J;?~.9±: '': : n:~,.~...tmn.;mJJ&l.t;:,UnicioJl c{':u:cc riskasscssor'' is .fkxibkcn~ 
r~;smo,d ... t(,U.hc .J:ln.tidp~l~d _&:h£t.ng;s;f:., 
Hazard tree: The term haznrd rree has been made more ~pecitic to rhc s;J!JJ:GJJtJ?~~lS4 
International ~ociety of . \rboriculture ~~ill~d~ :-o that a more objecti\T eYaluation can be 
made a!' to what constitutes a hazard tree . ;\ tiered S~' Stem of rating hazards ensures the risks 
a:-sociated with small diameter tree parrs arc not understated while the risks associated \Vith 
large diameter tree parts arc not overstated. 
'.[bt .. 1S£:\i.§in .... Jh.~ .... P±l?S:.\,:.§.§ ..... ~.!WJ.Jltiu&Jhc ... PN.W.lS,\ ... mogra.'.ItintG.1~.!1at.iqn.aJlr, ... H.s.~~y·GY.G.r •.... in 
thc: .proccss .of~H..i~~I!IPgmnl fnJ: . inrrrna rinna.Lktsc.rs.,thcJS.:\. expc.c.ts .m.mo.difr .. s.wru.: 
ofits ... .a.spcc.t.s, .... :Ihc .... cux.r.c.ntJ~ .t:JS£1St\ .... !lP.IJl<::'. 1.~iba.l .... l2i1 .~.GG.,,;iJ;.:;; .oc.m. is.includcdjodJPP-Cnlii.x ... l""OLJ:Mi 
J:: .t.;fGJ.G.n.~_Gd .... h;_:,_thc_dcfmi.tion ... Qf .. ''hazan.i._q·et'',_lf ... tbr .... rl .. \Jm<.:J:ical ... ~)' Stcm .. i~ .... 1:rxiscJju_~t\JJ:C,, 
iunaxbrrtnlac:c!.:l. 'Vi~h th~~;ial,g_<,l~.r,1iJ,em , 
1 nore: re-ordering of the cummcntary sectjon is retp.1irccl to place terms in alphabetical order] 
[ }~· 79ll. 030 --~£!~~!~ For-cs_rr_..·y_l_)l_a_n_l_~c_·y_._u i_re_·t_n_et_l_ts ________________ ----' 
I~ 
Housekeeping Amendments to the Urban Forestry Code Revisions 
U rbHn fore~ try plans are re<.Juired to be developed by a landscape architect or a person 
cerr:ified H!< .thati~ borh aft ~r_tifie,d arbori~t and rree risk assessor. Many arborists Q.Ql§_C§S 
lmth . .gualificarioos are dual certified, and adding rhe new requirement for tree risk 
assessment will help ensure sa fe conditions during and after construction. 
18.790.070 ?v1odification to the Urban Forestry Plan Component of an _\pproved Land 
Use Pcnnit 
'1\vo levels of modifications to the urban fore stry plan component of an approved land usc 
permit will be allowed. .Minor modification \:viU be con1pleted as a staff level, technical 
review. 'fhe following items would be considered minor modifications: 
• Removal of hazard trees if there is sufficient documentation by thc .. .arborist or 
landscape architecr a certified tree risk atlse~lS01'; 
r ------------------------------------------------------------------~ Amendment 5: Ensure consistency between the Site Design Standards (Secrjon '18.620.030) 
and Landscaping and Screening (Section 18.620.070) in the Tigard Triangle Design 
St<mdards. Applies to Ordinance No. 12-09 
Code/Manual Section: 'Tigard De,·clopmcnt Code Section 18.620.030 .. \ (Site Design 
Standards) 
3. 1::.· ronr yard setback design -Landscaping, an arcade, or a hard-surfaced expansion of 
the pedestrian path must be provided between a structure and a public street: or acccssway. 
If a building abuts more than one street, tl1e required impwverncnts shall be provided on all 
streets. Landscaping shall be develo )ed to .rhc_a . · abJc..s.raudard .. in.&.ction 18.6.20.03_~}.,_5. 
- . , . . ".. Hard-surfaced area:; 
shall be constructed with scored concrete or modular paving m aterials. Benches and otl1er 
street furni shings are encouraged. These areas shall conu·ibutc to the minimum landscaping 
requirement per Sect.lon 18.520.040H and 'T'able 18.520.2. 
5. Parking location and landscape design - Parking for buildings or phases adjacent ro 
Imblic street rights-of-wav must be located ro the side or rear of ncwlv constructed buildings. ~ J ' . 
If located on the side, parhlng is limited to S() <j~> of the street frontage. ilttcl }¥kn_ahuttiug 
public streets parking must be behind a landscaped area constructed to an L-1 LandscRpe 
Parkjng Lor~n Standard. The minimum depth of the L-1 landscaped area is eight feet 
or is equal to the ~ecru building setback, whlchever is greater. AU other site landsqping 
Interior ~;ide and rear yarcl8 sha ll be landscaped to a.u l,-2 Landt<cape GeneraLLandsc.a14illg 
Standard, except where a J.idc yard abuts n public ~m·eet., \Vherc it tlhall be land:;cftpcd to an L 
l Lancbcape ?;tandard. Ihe_L:.L.arui I ,-2 Standards 1).+-!;JPOJ:e fiil_!ysJe;zt]·ib!;Jjn;)(;;~liQll 
18.620.070. 
JiJ 
Housekeeping Amendments to the Urban Forestry Code Revisions 
1 Amendtnent 6: Ensure consistency between the Site Design Standards (Section 18.630.050) 
and Landscaping and Screening (Section 18.630.090) in the Washington S<]uare Regional 
Center Desi(!11 Standards. Anolies to Ordinance No. 12-09 
Code/Manua l Section: Tigard l)en·lopn•cnt Code Section 18.630.050 .. \ (Sire Design 
' Standards) 
1. Front yard setback design. 
a. Purpose. The from yard is the musr conspicuou~ face of a building and requires 
· specia.l anenr·i·o n .. Places for l) .. eoplc '.111d p edes trian m. O\T.mc. nt helps create an. actin.~ and 
I safer street. Higher le\-el of an<hcape anticipates a more immediate visual rcstllt 
b. Standard. For setbacks greater than (l feet, landscaping, an arcade, or a hard-surfaced 
, expansion of the pedest..rian parh musr be provided between a structure and a public street or 
accessway. If a building abuts more than one street, the required improvements shall be 
pn>,·ided on all sr.reets. Landscaping shaH be develo )ed to ' ___:__::_ ____ ::-'--- i 1 · ~:~c:.tiun 
18.630.050. \.5 , , · . . Hard-
su!Ta(:ea;;;.eas shall be constructed with scored concrete or modular p;n-ing materi-als. 
Benches and other street fmnishings arc encouraged. These area~ shall comribute to the 
minimum landscaping requirement per Section 18.520.040.B and 'I'ablc '18.520.2. 
5. Parking location and landscape design. 
a. Purpose. The emphasis on pedestrian access and a high (]ualiry strcetscape 
cxpcriL"nce rC(]UitTs that prinlte parking lots that abut public streets should nor be the 
predominant srreer feature . Where parking does abut public st.reets, high quality landscaping 
should screen parking from adjacent pL"destrian areas. 
b. Srandard. Parking for buildings or phases adjacent ro public street right~-of-way must 
be located to the side or rear of newly constructed buildings. \XIhen buildings or phases :ue 
adjacent to more than one public street, primary :-;rreet(s) shall be identified by the City 
\vherc this requirement applie:-;. In general, streets with higher functional classification will 
be identified as primary st.reet:> unless specific design or access factor:; favor another street. 
If located on the side, parking is l.imitcd to 50°/o of the primary street frontage, ft1W .}Vhen 
ahYIJiOZ-P-1Jblic srreers._parking must be behind a landscaped area constructed ro an L-1 
landlicape Parkin~r Lot Screen standard. The minimum depth of the ] ,-1 landscaped area is 
eight feet or is CLJUal ro tl1c adia&:<:.:JH building setback, wluchever is greater. \II Jltber _ §iJ~ 
lanJ.:lscaping Interior ~lide and real.' yard~ shall be landscaped to ag L-2 land.lcape (rt;ucral 
Lru:1dscapin,g standard , except. where a ~iide yard abut; tt pubbc :nrect, where it ~;ha:J+-b.e 
lancbcaped to an L l l:wdL<el'lpe ,<randard. DlcJ...~.::laJlQL:Z _§Ja!;t~l ards arc mqn;Jq\ly 
dc.scrib.cd in Section 1 H .. 6)£.U/2_U, 
2U 
Housekeeping Amendments to the Urban Forestry Code Revisions 
Amendment 7: Ensure consistency between the Site Design Standards (Section 
18.640.200.13) and Landscaping and Screening (Secrion 18.640.200.D) .in the Durham Quarry 
(i.e. Bridgeport) Design Standards. Applies to Ordinance No. 12-09 
Code/Manual Section: T'igard DcYelopmcnt Code Section 18.640.200. B (~ire Design 
Standards) 
3. From vard setback desig·n. For setbacks greater than zero feet, landscaping. an arcade, 
or a hard-surfaced expansion of the sidewalk shall be pnwided bcrwcen a structure and a 
public street or access\.vay. J fa building abuts more than one street, thl~ required 
Improvements shall be pro\ridcd on all streets. L.andscaping shall be developed to the 
applicable ~1!\JJ..sJ.iJIQ in S(;;ction 18.G4Q20lHL5. an L 1 :<nmdard on public streel9 and fH'\ L 2 
:<tandafd on acce:<:;wav,;. Hard -surfaced areas shall be constructed with scored concrete or 
modular paving materials. Benches and other street furni~hings are required . These areas 
shall contribute ro the minimum landscaping requirements. 
5. Parking location and landscape design. Parking for buildings or phases adjacent to 
public street rights-of-way shall be located to tht~ side or rear of newly constructed buildings. 
\X1hen buildings or phases arc adjacent to more than one public street, primary street(s) shall 
be idcnrificd where this rCLJUiremcnt applies. If located on the side, parking is limited to 501~10 
of the street frontagea fl1'ltl. \Vben abunin&r ,PLJhlic srrcet::;,._.parking nn1st be behind a 
landscaped area constructed to an L-1 bmdscape Parkir.Jgl.tPtSs;n,:hn Standard. The 
minimum depth of the L-1 landscaped area is eight feet or is ec11u1l to the _\J,Qi_a<;rnt builJing 
setback, whichever is greater . ..cill.otber site landsca~ Interior ,;ide and fear yaub shall be 
landscaped to an L-2 l.andscape GeneralLaud.s..c.aping Standard except where a Jide yard 
abuts a public st:teet, v.'here it shall be land:;caped to an L 1 Landscnpe Sranda.t'd. Sec Section 
18.640.200.D 
Amendment 8: Correct a cross reference in Section 18.790.050.C2 (J\djustments to 
Setbacks): Applies to Ordinat1ce No. 12-09 
Code/Manual Section: Tigard Development Code Sectjon 18.790.050.C.2 (Adjustments to 
Setbacks) 
2. ;\djustmcnts to Setbacks. The following setback reductions will be allowed for lots 
preserving existing trees using the criteria in subsection b !,\ below. 
21 
Housekeeping Amendm en ts to th e Urba n Forestry Code Revisions 
,.-:---·------·-----·--·-· ·----::------------:----:--:c--:---:-:----------, 
Amendment 9: Correct a cross reference in Section 18.790.050.(.3 (Adjustm<:nts to 
Sidewalks). Applies to Ordinance No. 12-09 
Code/Manual Section: Tigard DeH:·lopnwnt Code Section 1 H.790.050.C.1 (:\djustm en ts to 
Side\valks) 
3. -'\djusnnents to Sidc\\'alks .... 1 fa preserved rrce is to be utilized as a stree t tree, it 
must meet the criteria found in the Landscaping and Screening Section 1 ~. 74 5.(l40 .. \ .-3{i. 
22 
Housekeeping Amendments to the Urban Forestry Code Revisions 
Amendment 10: During the development of the tree grove preservation incen tives, the 
initial proposal was to require permanent preservation and management of tree groves if 
applicants utilized any one of the preservation incentives (dens.ity transfer, increased building 
height, setback reduction, etc.). While rhe Citizen Advisory Committee agreed that 
pennanent preservation was appropriate, they advised staff to strike the management 
requirement. Their rationale was that the management requirement could be seen as onerous 
by appLicants and act as a disincentive to preservation. Staff sr:ruck d1e management 
requirement for most of d1e preservation incentives, but inadvertently failed to strike the 
requirement for two of the .incendves. The purpose of the following amendments is w strike 
the remaining management re<.1uirements consistent with the Citizen Advisory Committee 
recommendation. ArmHes to Ordjnance No. 12-09 
Code / Manual Section: Tigard Development Code Section 18.790.050.D.3 (,\djustments 
to Commercial Development Standards) 
3. .\djmtmenrs to Commercial De,'t:lopmcnt Standards. ,\djustments ro Commercial 
Development Standards ( l'aolc 1 H.520.2) of up to 50 percent n:duction in minimum 
setbacks and up to 20 feet addi tional building height are pennitted prm·ided: 
g. The significam tree grove is protected through an instrument or action subject to 
approval by the director rhat demonstrates it will be permanently presetTed ~anaQ'eJ such 
as: 
Code/Manual Section: Tigard Development Code Section 1 H.. 790.0SO.D.6 (i\ djustmcnr ro 
Street and Utility Standards) 
6. Adjustment ro Street and Urjlity Standards. If requested, the director shall use his or 
her discretion when com:idcring adjustments w Chapter 1 R.81 0, Street and Utility 
Jmp n)\'Cment ~tandards and Section 18.745.(140, Street ·rrees provided: 
b. 'T'he significant tree grove is protected through an imtrumenr or acrion subject to 
approval by the director that demonstrates it will be pcnnanently preserved and mana~ed 
such a~: 
23 
Housekeeping Amendments to the Urban Forestry Code Revisions 
Amendment 11: One of the goals when revising the Urban Forestry Standards for 
Development was to clarify when an urban forestry plan for development is "in effect". The 
purpose of the clarification is to avoid the current situation where fumrc homeO\:vners must 
amend their land usc approvals to remove trees that were reguired with development. 
J nitially, the term ''active" was used but was later replaced \vith "in effect" since that term is 
more commonly used in the land usc process. 'fhe term "active" was inadvertently left in 
Section 18.790.060 and the purpose of this amendment is to replace it with "in effect". 
·-~_Eplies to Ordin~~ .. _ce_N_o_._1_2_~_09_· ____________________ __, 
Code/M anual Section: T'igard Development Code Section 18. 790.060 (Urban l'orcsrry 
Plan 1 mplemenra rion) 
B. Inspections. lmplcmentarion of the urban forestl·y plan shall bc inspected, 
documenred and reported by the projccr arborist or landscape architect whcneycr an urban 
forestry plan is ~ in_f::ffl"hJ ... 
-----
Amendn1ent 12: Correct spelling errol' of a t.rcc's common name in rhe Urban Foresrr)'--l 
Jvlanual. Volume IV- lJrban Forestrv Manual- Not codjfied. j 
Code/M anual Section: Urban ForestrY 1\lanual ,\ppcndix 2 (St.n .. Tt Tree List - Small 
Stature Trees) 
C loryblowcr ... 
24 
Housekeeping Amendments to the Urban Forestry Code Revisions 
Amendment 13: Generalize cross .references from the code to the Urban Forestry Manual. 
If the administrative rules are modi.fied during the upcoming administrative rule adoption 
process or any other future date, this \\":ill make the process more efficient by m·oiding the 
necessity of making changes to corresponding cross references in the code. Applies to 
Ordinance No. 12-09 and 12-11. Ordinance No. 12·09 affects Title 18 also known as 
the Community Development Code while Ordinance No. 12-11 covers affected 
chapters in the Tigard Municipal Code consisting of active and reserved Titles 1-17. 
Code/Manual Section: Tigard i\funicipal Code Section 8.02.050.1 (Ha:r:ard tree related 
definitions) 
1. "Claimanf'- Any person that believes in good faith there is :1 hazard tree on a 
property, can demonstrate that their life, limb or property has the potential to be impacted 
by said tree and seeks resolution through the llazard Tree Evaluation and i\batem.ent 
Procedure specified in Section 1 of the Urban r•·orestry Manual. 
5. "Respondent" - .-\ny person that receives notice from a claimant seeking resolution 
through the Hazard Tree r~:,·aluation and Abatement Procedure specified in Sectioft 1 of the 
Urban Forestry Manual. 
Code/M anual Section: Tigard Municipal Code Secrion 8.06.030 (Hazard 'Tree Evaluation 
and .-\batement Procedure) 
A i\ny claimant may seek re8olution through the Hazard 'free Evaluation and Abatement 
Procedure specified in Section 1 of the Urban Forestxy Manual. 
B. Once initiated by the claimant, both the claimant and respondent have an obligation to 
complete the Haza1·d Tree Eva.luation and Abatement Procedure specified in Section 1 of the 
Urban Forestry Manual. Failure of the claimant or respondent to perform their obligations 
specified in the IJazard 'I'ree Evaluation and Abatement Procedure constitutes a ,-]olation of 
this code by the negligent party. 
Code/Manual Section: 'figard rvfunicipal Code Section 8.06.040 (I;: rnergency Abatement 
Procedure) 
If the city has reason to believe a hazard tree poses an immediate danger and there is not 
enough time to con1plete the Hazard Tree Evaluation and Abatement Procedure infection 1 
ef the Urban Forestry Manual, the city rnay choose to take immediate remedial action as 
defined in Section 1.16.150 of the 'J'igard Municipal Code. 
Code/Manual Section: Tigard Municipal Code Section 8.08.030 (Street Tree Planting) 
No person sh<1ll plant a street tree ~~'0~1out prior written ap_JE:oval obtained thrg~h the City 
25 
Housekeeping Amendments to the Urban Forestry Code Revisions 
!Vlanager .Decision !\faking Procedures detailed in Section 8.04.020 using the approval criteria in 
Section 2, part 1 of ~Strq::t :free)))pminy _SJ.andard~jn the Urban Forestry ManuaL 
Code/.M'anual Section: Tigard l\ lunicipal Code Section 8.08.040 (Street Tree ?v1aintenancc) 
A. All street u:cc:; shall be maintained in a manner consistent with tl1e s;;}treet (.[ree 
ffi1,iain te nance sStandards specified in ~1 2, pan 2 of the Urban Forestry Manual. 
Code/Manual Section: Tigard l\1unicipal Code Section 8.08.050 (Street 'J'ree Removal) 
A. 'T'he City 1vLwager Decision Making Procedures detailed in Section ~.04.020 using rhe 
appro,Tal cri teria in 8ection 3, pan l oftl1eli.lli;~t:l'r<;GJ_\.e.Jll9Y_ilL~J}iQQ9fQf>in the Urban 
Forestry Manual; or 
Code/Manual Section: 'J'igard Municipal Code Sccrjon 8.08.060 (i'vlcdian Tree Planting) 
No person shall plant a mechan tree without p rior written approval obtained thro ugh the 
City i\lanager Decision I\Iaking Procedures detailed in Section 8.04.020 using the appronl 
criw-ia in Section 4, parr 1 of .tlJ_c ;\I<;di<tJLTrc<: Pl3Jlling Stan<..l arsi:' in the Urban Forestry 
1\.lanuaL 
Code/Manual Section: Tigard iv1unicipal Code Sectjon k.08.070 (Med ian T'rce 
tvlaintenance) 
A. _\lJ median trees shall be mai ntained in a manner consis tent wirh the t'f4\::lcdian (free 
ffiJ:daintcnance s~tandard s specified in Section-'!, part 2-of the Urban Forestry ]v!anual. 
Code/Manual Section: Tigard i\1unicipal Code Section 8.08.080 (t'.·fedian Tree Removal) 
,\. The City I'vlanagcr Decision 1\bking Procedures detailed in Sectjon 8.04.020 using the 
approval cri teria in Section 5, pan 1 ofdli:_.11cdian,l'n:c-E.<.~ms~y;) l St:and<l_nkiu the Urban 
Forestry Manual; or 
Code/Manual Section: Tigard Municipal Code Section 8.10.040 (Sensitive Lands Tree 
Removal) 
i\. The City i\fanagcr Decision .i\.iaking Procedures detailed in Section 8.04.020 using the 
approval cri teria in ::-~c c tion 6, part 'I of thrS<;,t,1?itiygl4\pd~~J\i:mQ);,;,~Stamhl!:d.s_ in the 
, Urban Forestrv Manual; o r i ' 
I Code/. Man. ual Section: '1\.(,r;.lrd \1 unicipal Code Section R.12.040 (Removal of Trees 'fhat Jr 
~~~rc Required \X!ith De.- e!<?P!!!~.t~ t)'---- .... ·------- ............. _____ ....... .. .... . 
26 
Housekeeping Amendments to the Urban Forestry Code Revisions 
-----1 
A The City Manager Decision l\1aking Procedures detailed in Secdon 8.04.020 using the 
appronl criteria in Sectjon 7, part 1 of thc;l)cvcl_t~tirc.c.l~TIQ2:ilLStf.l,QQll:±.sl.s. i1} the 
U rban l 'orestry l'\hnual; or 
Code/Manual Section: Tigard Municipal Code Section 8.14.040 (Removal ofTrecs that 
were Planted Using the Urban Forestry Fund) 
A. The City T\fanager Decision Making Procedures detailed in Section 8.04.020 using the 
apprm·al criteria in Secrion 8, part 1 of tlli.:=U.tl~anE~_?n'§l!~!JOQJrcc _R~moY.aLStandard~jn 
the Urban Forestry 1\:Ianual; or 
Code/Manual Section: Tigard Iviunicipal Code Sec6on 8.16.070 (Removal of lJer-itage 
Tree Designation) 
:\. 'fhe Ciry l\1anager Decision T\-faking Procedures derailed in Secdon 8.0-t020 using the 
approval criteria in Section!), part 1 ofthcJ::;Jeritag~: Tre.e_ l)~sjgJ,JatiqpJ\s:moYalSLillQ.fiJ:9.sin 
the Urban Forestry Manual; or 
Code/Manual Section: Tigard Development Code Section 18.745.040. /\ (Street 'l'ree 
Standards) 
I. Street tree:; shall be required as part of the approval process for Conditional Use 
( l'ype III), Downto\vn Design Review (I'ype II and III), Minor Land Par6tion (Ty pe 
II), Planned Development (rype III), Site Development Review (Type II) and 
Subdivision (I'ype II and 111) perrnirs. 
2. The minimum number of required street trees shall be determined by div.iding rhe 
linear amount of street frontage within or adjacent to the site (in feet) by 40 feet. 
\X!hen the result is a fraction, the rninimum number of required street trees shall be 
determined by rounding to the nearest whole number. 
3. Street n~ee s required by this section shall be planted according to the ~JJecr:J):g_<; 
l?.Ja_miog ~Standards in Section 2 of rhe Urban T'orestry ~-fanual. 
4. Street trees required by this section shall be provided adequate soil volumes according 
to the Sr.t:ect]~~];c SolLY olum(: sS_tandards in Section 12 of the Urban I.:<'orestry 
Manual. 
5. Street trees reguired by this sec tion shall be planted within the right of way whenever 
practicable according to the S,tr.cctTree PJa~ ~Standards in Section ? of the Urban i 
--- r:ore~!!I~!~nua_l: __ ?rrcet ~ees may !)e plan_!_ed n~ _~ore tha~1 6 ~~-~-!Jrom the right of I 
27 
I 
Housekeeping Amendments to the Urban Forestry Code Revisions 
--------------············~· .............................. -······ 
way according ro the -~llJ:ct'.l:J:(.;~J~J;uJling :i~tandards in Set-tion 2 of the Urban 
hll-cstry J\lanual when planting within the right of way is nor practicable. 
(). An existing tree may be u~ed to meet the ~trect tree standards provided rl1at: 
a. The largesr percentage of the rree trunk immediately above the trunk flare or root 
buttresses is either within the !'ubjcct site or within the right of way immediately 
adjacent to the :;ubjcct site; 
b. The tree would be permitted as a street tree according to the S,txs:sJTr<~s~J>Jar:u:ing 
.iJ.PSJ~qiLYnlHP!~ sStandards in Sectiom 2 find 12 of the Urban Forestry Ivlanual if 
it were newly planted; and 
c. "J'hc tree is shmvn as preserycd in the 'free Preservation and Rcmond site plan 
(per 18.7i)(l.(J3() .. \.2), "l'ree Canopy Cover site pl an (per 1 R.790.030.A.3) and 
~Supplemental d\.,eport (per 18.790.030.A4) of a concurrent urban forestry plan 
and is digible for credit towards the effcctiYe tree canopy cover of the site. 
Jn ca:-;c:- where it is not practicable ro pro\'idc the minimum number of required srrn·t 
rrecs, the Director may allow the applicant to remit payment into the Urban hJrestry Fund 
for tree planting and early establishment in an amount equivalent ro rhe City 's cost to plant 
and maintain a stree t tree for three (.3) years (per the S.trcct_Ir~GI~l;;Jilling s;)randards in 
~.ion 2 of the Urban Forcsuy i\fanual) for each rrce below the minimum requi red. 
Code/Manual Section: 'J'igard Development Code Section 18.745.0SO.E.1.a (Screening of 
parking and loading areas is ITCJuircd) 
(4) 1\ll parking areas, including parking spaces and ai~;Jcs, shall be rectLLired to achieve at 
least )(Y',~ ) tree canopy coYer at maturity directly above the parking area in accordance with 
rhe Parkirw Lot Tree C:ano1w Standards in Sccrion ·13 of the Urban l 1orestrv f\l anua l. b - ./ . 
Code/Manual Section: Tigard Development Code Section 18.790.030 (Urban Fore stry 
Plan Rec]uircmcnrs) 
,-\. Urban T;ore~trr Plan Rec] uirements. ,\n urban forestry plan shall: 
·t. Be coordinated and approved by a landscape architect (the project landscape 
architect) or a person possessing dual certifications as a certified arborisr and certified tree 
r isk assessor (the project arborist) ; 
2. [\feet the tirce r£rescrvarion and fl\emuval sSirc p,£lan standards in Section 1 (j_ Dart 
-h:-rf the Urban r:orestrv i\Ianual; 
• .. -·"'-····················-·-·-·····-······-··-··--··--···-····-···-- -----
2~ 
Housekeeping Amendments to the Urban Forestry Code Revisions 
3. 1\lcet the t;,[rce e£:;Jnopy R~ite pl!lan standards in Sectjon 10. nan 2 of the Urban 
Foresu-y [vlanual; and 
4. J',1cet the ~~upplernental'fE,cport standards in Section 10. oart 3 of the Urban 
hncsrry ~Janual. 
B. Tree Canopy Fee. If rhe s~upplcmental fll,cporr demonstrates that the applicable 
standard percent effective tree canopy cover in Secrion l~t+,-it-em-N 'vvill not be 
prov.ided through any combination of tree planting or preservation for the overall 
development site (excluding streets) or that the 15 percent effective rree canopy cover will 
not be provided through any combination of tree planting or preserYation for any indi,·idual 
lot or tract in the R-l, R-2, R-3.5. R.-4.5 and R-7 districts (when the overall development site 
meers or exceeds the standard percent effective tree canopy co,·er), then the applicnnt shall 
prcJ\·ide the city n tree canopy fee according ro the methodology outlined in m~T.rccCano.p.y 
Eec_Calc:LJlatiunRcquit.cm.c.n.ts. ..  in Section 10, p!trt 4 of the Urban Forestry tvJanual. 
Code/M anual Section: Tigard Development Code Section 18.790.040 (Discretionary 
Urban Forestry Plan Rcdew Option) 
.\ . General Provisions. J n lieu of providing payment of a tree canopy fee when less than 
the standard cffectjve tree canopy cover required by Section-Uf;-t'}ffl~f the Urbnn Fore:my 
?\lanual \vill be provided, an applicant may apply for a discretionary urban forestry plan 
review. 'l'he discredonary urban forestry plan review cannot be used ro modify an already 
approYed urban forestry plan, any tree preservation or rrec planting reguirements established 
as parr of another land use review approv;ll, or any tree preservation or tree planting 
requirements required by another chapter in this title. 
Code/Manual Section : Tigard Dc,·elopmcnt Code Section 18.790.050.1).1 (Reductio n of 
Minimum Density) 
b. The project arborisr or landscape architect certifies rhe preservation is such that the 
connectiY:ity and viability of the remaining significant t.ree gro\·e is maximized while 
b alancing the SigniJih!lOt :Ct\:cJ1rm:eP.rescrv.atio.n e,Considcrations in Section 10. nnrt 
§ -<"tf the Urban l:;'orcstry Ivlanual; and 
Code/Manual Section: Tigard Den:lopment Code Section 1H.790.050.D.2.a (Densiry may 
be transferred provided that:) 
(ii) The project arborist or landscape architect certifies the preservation is 
such rl1at the connectivity and viability of the remaining significant tree 
·--- ·----'g"-r_o_,_•e i.~ ~~!l.~i.~!.?.~~~~l .. :vhilc ba_l~~~ing the ~igpificantJ ~r_q:_G~ 
29 
Housekeeping Amendments to the Urban Forestry Code Re vis ions 
En.:.SJ.:1L1tilln e.!,~onsiderations in &ction 10. oart 5 of the Urban 
Forestry .\lanual; 
Code/Manual Section: Tigard DcYclupmenr Code Scctjon 1 H.790.050. D .:1 (,\djustnJcnts 
to Commercial Den:lopmcnt Sundards) 
..... l 
I 
b. The project arbori~t or landscape architect cerrifie~ rhc prcsct"Yation is ~uch thar the 
connectivity and , -iability of the remaining significant tree gron~ is maximized while 
balancing the S,igv,jJ]};!\Pt.[r~·LG.J:QYc. PJ:c~cXY.atil!n c(~on:;idcratiom in ~:ection I 0. nan 
fH:rf the Urban hJt-cstry f\Janual; 
Code/Manual Section: Tigard Den~lopmcm Code Secrjon 1 K. 790.050.D.4 (. \djus tments 
to Industrial De, elopment Standar(h) 
b. The project arborist or landscape architect certifies the preservatjon is such that the 
connccti\' ity and Yiability of the remaining signi fi cant tree grm-c is maximized while 
balanc ing the SigniJkanri:rc~"£i.J:Q.H Pn:~crratim1 c,Considerarions in Section 10. nart 
~the Urba n l ;o rcstry f\1anual7; 
Code/Manual Section: Tigard Den·lopmcnt Code Scctiun UU90.050.D.5 (:\djusrmenr ro 
i\finimum Effccrin~ ·rree Canop~· Cover Requiremen t) 
b. The project arborist or landscape architect certifies the prcscn·atiun is such that the 
connectivity and ,-iabiliry of the rcmnining significant txec gro,·c is maxim.ized while 
balancing the S4r.uiJ1~4nt~1):~&-oGroYl:J?r<.:scxyatiD.n c(;onsiderations in ~eetion ·1 0 . nan 
Sf}f the U rbnn ForestrY i\lanual; 
Code/Manual Section: Tigard [)cycJopment Code Scninn 18.7lJU.050.D.C, (. \ djusrrnent to 
Su~ccr and Utility Standards) 
a. The adjustnlC'nts will facilitate pt-csctYation and help to maximize the connccrj,·iry 
and \·iabiliry of a significam tree g ro,·c w hile balancing the Signif.l.caJJ.,J:,])Tt{;rg':~ 
J~h.~~.£-JYi:ltir?n e,Lonsidcrarions in Section 1 !J, parr 5 of rhc Urban l"tJt·estx:• i\Ianual; 
Code/Manual Section: Tigard DCYclo pment Code Section 18.7')().0(,() (Urban Forestry 
Plan I mplcmcntat.ion) 
B. Inspections. lmpkmenration of the urban furesb~· plan ~hall be inspec ted , 
docurncntcd and reported by the project arborist or landscape architect w hcne\-cr an urban 
fo restry plan is acci\'c. T n addi6on, no person may refuse entry or access to the director for 
the purpose of m o nitoring rhc urban forestry plan on any site with an cffcct:iYe urban 
forestry plan . The tlmpectiun i',llcyuiremcnts i~~- t!~c;rjon 11, pan I of_!._hc L!._:!?an h)~~strv _ 
:10 
Housekeeping Amendments to the Urban Forestry Code Revisions 
Manual shall apply to sites with an effectjvc urban forestry plan. 
C. Tree Establishment. The establishment of all trees sh()\Vn w be planted in the tiree 
cC,anopy s~itc pl:lan (per 18.790.030.:\.3) and sS,upplemcntal r!leport (per 18.790.030. :\.4) 
of a previously approved urban forestry p lan shall be guaranteed and required according to 
the ([ree e~stabJjshment r]lequirements in ~cction 11, pflrt 3 of the Urban Forestry Manual. 
D. Urban l' orest l nYentory . Spatial and species specific clara shall be collected according 
to the tt!_!rban .fl:orestry ilnvcntory r.JlcquiJ:cments in Section H, pan 3 of the Urban 
l '"oresr.ry i\-fanual for each open grown tree and area of stand grown trees in the tirec 
eCanopy s~itc pJ~hn (per 18.790.030.:\.3) and s_S,upplcmental rJlcpon (per 18.790.030.A.4) 
of a previously approved urban forestry plan. 
Code/Manual Section: Tigard Development Code Section 18.790.0/ 0.B (L•:xemptions) 
B. Exemp6ons. The following activities shall be exempt from the Type I !VfoJjficatjon 
to the Urban Forestry Plan Component of an :\ppnwed Land Usc Permit process: 
1. Removal of any tree shown as preserved in rhe -tircc e~anopy ~.iiite pElan (per 
18.790.030.1\.3) and sSupplemcntal rJleport (per 18.790.030.A4) of a previously appnwed 
urban forestry plan pro\'ided: 
a. The project arborist or landscape architect provides a \vrittcn report prior to removal 
attesting thar either the condition rating (pet" Sec6on 10, part 3, item D .7 of rhe Urban 
Fore:m:r Mnnual) or suitability of preservation rating (per &eet:i<m-H},-part 3, item D .8 of the 
S~JP.J2lcmcntaLRcport RelJuircment§ _jJ!JJJ~ Urban Fore~my Ivlanual) of the tree has changed 
to a rating of less than 2; and 
. b. .:\ revised tiree e,Canopy ~Sitc pJ;!lan and sSupplemcntal r,E,eport are submitted for 
' review and approval prior to removal that reflect the proposed changes to the preYiously 
approved urban forestry plan. The rcvjscd f]:rcc eCanopy ~Site pl:,lan and ~Supplemental 
ftf-be-ri-st :rE.,eport shall demonstrate how the effccti\' t' tree canopy cover requirements ffi 
Sec cion 10, p1-1rr 3 of the lJ rban Forestry i\'Iaftt:tft! will be proYided ~)y rrec planting, 
preservation and/ or payment of a tree canopy fcc in lieu of plandng or preservation. i 
- ------------· ____ _j 
.31 
Proposed Administrative Rule 
Urban Forestry Manual Section 1- Hazard Tree Evaluation and 
Abatement Procedures 
Administrative Rule No. 
Effective Date: 
8.06.030 
TMC # 
N\Cl.VCJ/\ I, W\3 
01 01 
Rule # Version # 
1. Description 
This section of the proposed Urban Forestry Manual creates a process for the 
reconciliation of hazard tree disputes between neighboring property owners. 
2. Sections 
Please see Section 1 of the proposed City of Tigard Urban Forestry Manual in the City of 
Tigard Urban Forestry Code Revisions Volume IV (attached). 
Approved by: ~ ., 
l__/f/l1M#'bu~ /' 31· d)o;g 
Martha L. Wine, City Manager Date 
P:tg<· I \dminiqr;tti\"L' HulL· '-.o ;..: !J(,r; o,r :. 11]-111 l·:fft-cttn D:nc: 
Proposed Administrative Rule 
Urban Forestry Manual Section 2, Part 1- Street Tree Planting 
Standards 
Administrative Rule No. 
Effective Date: 
8.08.030 
TMC# 
~OXGV\ I 1 1..0 13 
01 01 
Rule# Version# 
1. Description 
This section of the proposed Urban Forestry Manual creates a process for property 
owners to plant trees along streets. 
2. Sections 
Please see Section 2, Part 1 of the proposed City of Tigard Urban Forestry Manual in the 
City of Tigard Urban Forestry Code Revisions Volume IV (a ttached). 
Approved by: . _ /J (\ '"' 
~~ 1·31·~;3 
Martha L. Wine, City Manager Date 
1\tge] \dmint~'ILtli '.T Fule '-." •l. k.ii~.!!.) 1 i II) 111 1 · r ItT lin D,l, e: 
Proposed Administrative Rule 
Urban Forestry Manual Section 2, Part 2- Street Tree Maintenance 
Standards 
Administrative Rule No. 
Effective Date: 
8.08.040 
TMC# 
.MLLV"c.Vl I 1 1-0 I 3 
01 01 
Rule# Version# 
1. Description 
This section of the proposed Urban Forestry Manual creates a process for property 
owners to maintain trees along streets. 
2. Sections 
Please see Section 2, Part 2 of the proposed City of Tigard Urban Forestry Manual in the 
City of Tigard Urban Forestry Code Revisions Volume IV (attached). 
Approved by: . ~() . 
L--1A!JdA~ / r :3/. d--<J /3 
Martha L. Wine, City Manager Date 
P~lf2C 1 \ciP<ttmtrati·:c J\ul•· '-n. :\.'1~.11-l!i 11].11] 1 :ffccttn D:ttL·: 
Proposed Administrative Rule 
Urban Forestry Manual Section 3- Street Tree Removal Standards 
Administrative Rule No. 8.08.050 01 01 
TM C # Rule # Version# 
Effective Date: ~ClX"Ck\ IJ '2.0 13 
1. Description 
This section of the proposed Urban Forestry Manual creates a process for property 
owners to remove street trees. 
2. Sections 
Please see Section 3 of the proposed City of Tigard Urban Forestry Manual in the City of 
Tigard Urban Forestry Code Revisions Volume IV (attached). 
Approved b.y: ~ Lfvt ~. 
Martha L. ~nag;:, I ·3l d---e>/3 Date 
p,Jg( I .\dmini,Jr;Jii\c Pulr· '-·o. ~_,,;;.q_:,(, II] (I ] I :ff, <"In l ]);~It: 
Proposed Administrative Rule 
Urban Forestry Manual Section 4, Part 1- Median Tree Planting 
Standards 
Administrative Rule No. 8.08.060 01 01 
TMC # Rule# Version # 
Effective Date: MaKCNI \ 1 '20 I '3> 
--------------------------------
1. Description 
This section of the proposed Urban Forestry Manual creates a process for property 
owners to plant median trees. 
2. Sections 
Please see Section 4, Part 1 of the proposed City of Tigard Urban Forestry Manual in the 
City of Tigard Urban Forestry Code Revisions Volume IV (attached). 
Approved by: ? (\ 
\_-1/}1 ~CC:J~ 1 ~ B r ·~ ol3 
~ 
Martha L. Wine, City Manager Date 
l'.lp.<· I \dminiq r :l ll'.l' Hulc "o. :-;.!,~Ji(,'i II] II] rfflclin D:ut: 
Proposed Administrative Rule 
Urban Forestry Manual Section 4, Part 2- Median Tree 
Maintenance Standards 
Administrative Rule No. 
Effective Date: 
8.08.070 
TMC# 
MCU'c.Xl I I '2-0l?. 
01 01 
Rule# Version# 
1. Description 
This section of the proposed Urban Forestry Manual creates a process for property 
owners to maintain median trees. 
2. Sections 
Please see Section 4, Part 2 of the proposed City of Tigard Urban Forestry Manual in the 
City ofTigard Urban Forestry Code Revisions Volume IV (attached). 
Approved by: 
l-(/JJ} ~aJ-~ (. ~I . ;2.0/ ~ 
l 
Martha L. Wine, City Manager Date 
P:l!-',< · l \dmini-;~r;ttr:c Pule "-'n. ~.i!S.i•-ii II] II] I :fiLctin D:11<: 
Proposed Administrative Rule 
Urban Forestry Manual Section 5- Median Tree Removal 
Standards 
Administrative Rule No. 
Effective Date: 
8.08.080 
TMC# 
Mo..v'-VI \ I "2.0 I '3 
01 01 
Rule # Version # 
1. Description 
This section of the proposed Urban Forestry Manual creates a process for property 
owners to remove median trees . 
2. Sections 
Please see Section 5 of the proposed City of Tigard Urban Forestry Manual in the City of 
Tigard Urban Forestry Code Revisions Volume IV (attached). 
Approved by: t-flntttd~ /3{- ~0 1 5 
Martha L. Wine, City Manager Date 
P:t)2l I \dmini~'tratiw Fuk ''l. ~-r;~,_ll~!J OJ Ill Effl'Clin' D;llt·: 
Proposed Administrative Rule 
Urban Forestry Manual Section 6- Sensitive Lands Tree Removal 
and Replacement Standards 
Administrative Rule No. 
E ffective Date: 
8.10.040 
Tl\fC # 
t'\o..v~ l ., 1.013 
01 01 
Rule# Version# 
1. Description 
This section of the proposed Urban Forestry Manual details the approval criteria for 
sensitive lands tree removal though the City Manager Decision Making Procedures (Part 
1 ), including Sensitive Lands Tree Replacement Standards (Part 2). 
2. Sections 
Please see Section 6 of the proposed City of Tigard Urban Forestry Manual in the City of 
Tigard Urban Forestry Code Revisions Volume IV (attached). 
Approved by: 
U/11~~ I, 3(· .:2-o I J 
Martha L. Wine, City Manager Date 
P:l!J~' I .\dmml,lr:JIJH· Puk ""· ~.]11.!!-l!i II] II] Fffen1n D:11e: 
Proposed Administrative Rule 
Urban Forestry Manual Section 7- Development Tree Removal 
and Replacement Standards 
Administrative Rule No. 
E ffective Date: 
8.12.040 
TMC # 
MllVCN'\ I ) '2.0 \3 
01 01 
Rule# Version# 
1. Description 
This section of the proposed Urban Forestry Manual details the approval criteria for 
development tree removal though the City Manager Decision Making Procedures (Part 
1), including replacement standards for development trees (Part 2). 
2. Sections 
Please see Section 7 of the proposed City of Tigard Urban Forestry Manual in the City of 
Tigard Urban Forestry Code Revisions Volume IV (attached). 
~~& I· 3l ::J-ot-3 
Martha L. Wine, City Manager Date 
J';tpt \dmini,:tratin· Full ,.o.1-l.l,.,.'i..J 1 i II] II] l ·Jfcui1 l Date: 
Proposed Administrative Rule 
Urban Forestry Manual Section 8- Urban Forestry Fund Tree 
Removal and Replacement Standards 
Administrative Rule No. 
Effective Date: 
8.14.040 
TMC# 
Mu.vc.NI ' I 1-01 ~ 
01 01 
Rule# Version# 
1. Description 
This section of the proposed Urban Forestry Manual details the approval criteria for 
Urban Forestry Fund Tree Removal though the City Manager Decision Making 
Procedures (Part 1), including Urban Forestry Fund Tree Replacement Standards (Part 
2) . 
2. Sections 
Please see Section 8 of the proposed City of Tigard Urban Forestry Manual in the City of 
Tigard Urban Forestry Code Revisions Volume IV (attached). 
~~~~ j, :5/. J.of 3 
Martha L. Wine, City Manager Date 
P<!pl I \clm lnl>lr<l ll'-l H11lc "o ;.,_J-Ui-li' 111 111 J :ffL C!J\'( l);JIC: 
Proposed Administrative Rule 
Urban Forestry Manual Section 9- Heritage Tree Designation 
Removal Standards 
Administrative Rule No. 8.16.070 01 01 
TMC # Rule# Version# 
Effective Date: UUX'Ckl \''lei?:> ----------~----------------------
1. Description 
This section of the proposed Urban Forestry Manual details the approval criteria for 
heritage tree designation removal though the City Manager Decision Making Procedures. 
2. Sections 
Please see Section 9 of the proposed City of Tigard Urban Forestry Manual in the City of 
Tigard Urban Forestry Code Revisions Volume IV (attached). 
Approved by: 
\-//1;1~ I '.?1- :JDt-s 
Marilia L. Wine':-Gty Manager Date 
Pact I . \dmJni~1r:111n· Full"-.",,_ ~.J(:;-i ' II] flj J -:fftCJi\( l),,,,: 
Proposed Administrative Rule 
Urban Forestry Manual Section 10- Urban Forestry Plan Standards 
Administrative Rule No. 18.790.030 01 01 
TDC # Rule# Version # 
E ffective D ate: J.\c.lt'<...\1\ \' 1.013 
1. Description 
This section of the proposed Urban Forestry Manual details urban forestry plan 
standards including tree preservation and removal site plan requirements, tree canopy 
site plan requirements, supplemental report requirements, tree canopy fee calculation 
requirements and significant tree grove preservation considerations. 
2. Sections 
Please see Section 10 of the proposed City of Tigard Urban Forestry Manual in the City 
of Tigard Urban Forestry Code Revisions Volume IV (attached). 
Approved by: 
\AA~a<L& 
._..... 
Martha L. Wine, City Manager 
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i\S t\M I·:N D I·J) BY T ill ' 'J'IGi\RD CITY COUNCil. ON 
j 1\ NUt\RY 22, 2013. SI·T·: 12XJ II BIT B A LT t\ CI LED . 
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D ate 
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Proposed Administrative Rule 
Urban Forestry Manual Section 11- Urban Forestry Plan 
Implementation Standards 
Administrative Rule No. 18.790.060 01 01 
TDC# Rule# Yer,;ion # 
E ffective Date: M<1Xc...\'\ \ ,1-0\~ 
--------------------------------
1. Description 
This section of the proposed Urban Forestry Manual details urban forestry plan 
implementation standards including inspection requirements, tree establishment 
requirements, and urban forest inventory requirements. 
2. Sections 
Please see Section 11 of the proposed City of Tigard Urban Forestry Manual in the City 
ofTigard Urban Forestry Code Revisions Volume IV (attached). 
Approved by: 
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Martha L. Wine~ity Manager 
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1\ S :\M I<:NDED IW T ill ·: TIG 1\RD CITY COUNCIL ON 
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Proposed Administrative Rule 
Urban Forestry Manual Section 12- Street Tree Soil Volume 
Standards 
Administrative Rule No. 18.745.040 01 01 
TDC# Rule # Version# 
E ffective D ate: lftCLVCk\ \ 72.0 13 ~----~--~--------------------
1. Description 
This section of the proposed Urban Forestry Manual details street tree soil volume 
standards including soil volume requirements, soil volume calculation requirements, and 
soil volume plan requirements. 
2. Sections 
Please see Section 12 of the proposed City of Tigard Urban Forestry Manual in the City 
ofTigard Urban Forestry Code Revisions Volume IV (attached). 
Approv~~ by: _('\ ,. Ll11~ 
Martha L. Wine, City Manager 
P <l)-'l' I .\ dm llWi l:! l i·.l'Jl.llic'-o.J~. - ~ :, . ,;-f!ill l (I ] 
t\ S t\ M END I·:D BY '1'1 II ·: '!' ICARD CITY CO UNCIL ON 
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Proposed Administrative Rule 
Urban Forestry Manual Section 13- Parking Lot Tree Canopy 
Standards 
Administrative Rule No. 18.745.050 01 01 
TDC # Rule# Version # 
Effective Date: MO.XV\1\ \ , "l-0 \? 
----------------------------------
1. Description 
This section of the proposed Urban Forestry Manual details parking lot tree canopy 
standards including parking lot tree requirements, soil volume calculation requirements, 
and parking lot tree canopy plan requirements. 
2. Sections 
Please see Section 13 of the proposed City of Tigard Urban Forestry Manual in the City 
ofTigard Urban Forestry Code Revisions Volume IV (attached). 
Approved by: . /.., () ~ .. 
"--111~ 
Martha L. Wine, City Manager 
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1\ S AM r·:NOIC:D BY Till ·: TI Ci\IW Cl' lY COUN CIL ON 
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Date 
l·:ff, rti\'f D:11c: 
Proposed Administrative Rule 
Urban Forestry Manual Appendices 
Administrative Rule No. 00.000.000 
TDC # 
Effective Date: roa.rc.lo I • '2.01 o 
01 01 
Rule# \'ersion # 
1. Description 
This section of the proposed Urban Forestry Manual includes: 
• Appendix 1: Tree Risk Assessment Form 
• Appendix 2: Street Tree List 
• Appendix 3: Parking Lot Tree List 
• Appendix 4: Columnar Tree List 
• Appendix 5: Native Tree List 
• Appendix 6: Nuisance Tree List 
• Appendix 7: Example Tree Preservation and Removal Site Plan 
• Appendix 8: Example Tree Canopy Site Plan 
• Appendix 9: Example Supplemental Report Template 
• Appendix 10: Example Tree Canopy Site Plan for an Individual Lot 
• Appendix 11: Example Soil Volume Calculations for Street Trees 
• Appendix 12: Example Soil Volume Plan 
• Appendix 13: Example Soil Volume Plan for a Single Lot 
• Appendix 14: Example Covered Soil Volume Plan Drawings and 
Example Covered Soil Specifications for Street Trees 
• Appendix 15: Example Soil Volume Calculations for Parking Lot Trees 
• Appendix 16: Example Parking Lot Tree Canopy Plan 
• Appendix 17: Example Covered Soil Volume Plan Drawings and 
Example Covered Soil Specifications for Parking Lot Trees 
• Appendix 18: Example Parking Lot that Meets the 30% Minimum Canopy 
Cover requirement 
2. Sections 
Please see the appendix of the proposed City of Tigard Urban Forestry Manual in the 
City of Tigard Urban Forestry Code Revisions Volume IV (attached). 
Approved by: 
/·31 -:J_oi ._q 
Date 
!':tge I \dmim>Ir:Ill\ l' H.ulc ~-o 1 N.- -l_::, _r :_=,ii-111-111 I J(('LIIH' Date: 
To: 
From: 
Re: 
D ate: 
City ofTigard 
Memorandum 
Tigard City Council 
, \ D ~ !I N I S'I'R t\' 1'1\'1 ·: RULI 'S " X III BIT B 
Marissa Daniels, Associate Planner 
Potential Administrative Rules Amendments 
January 22, 2013 
Hearing council's desire for additional flexibility in the Administrative Rules, staff has prepared 
several amendments for your consideration on January 22, 2013. 
Potential Amendments to the Urban Forestry Manual 
Throughout the public hearing process for the code, staff heard from council several additional 
potential revisions to the Urban Forestry Manual to be made during the administrative rules 
adoption process. Most of the revisions are aimed at increasing flexibility of the manual. The 
following table summarizes the potential revisions, the relevant sections of the manual, whether 
the requirement is already flexible, staffs recommendation, and the reasons for staffs 
recommendations. While staff recommends council limit their approval to amendments 1, 2, 5 
and 7, amendments have been prepared for all 7 items. The specific text of the amendments is 
included on the following pages. Council will have an opportunity to ask questions of staff and 
deliberate on the revisions at the January 22, 2013 meeting. 
Requirement 
Potential Identified for Urban Forestry 
Amendment Potential Manual Already Staff Reason for Staff 
Number Amendment Sections flexible? Recommendation Recommendation 
1 Sheet size 10.1.A, 10.2.A, No Increase flexibili ty Flexibility OK as long 
12.3.B, 13.3.B as alternate sheet size 
is legible 
2 Bar scale 10.1.D, 10.2.D No Increase flexibility Flexibility OK as long 
as alternate bar scale 
is legible 
3 Driplines 10.1.], K, L, N o Do not increase Locating tree driplines 
(to scale) 10.2.H ,I, 10.2.L, flexibility on site plans is a best 
M practice and ensures 
conflicts are avoided 
4 Tree lists Appendices Yes Do not increase Already flexible, 
2-6 flexibili ty applicants not limited 
to trees on lists ! 
5 Tree spacing 10.2.L.1 -4, No, except Increase flexibility Allowing building 
and building 10.2.M.1-5 for building setback flexibility for 
setbacks setbacks constrained sites is 
downtown O K 
6 Tree setbacks 1 0.2.L.S-8, No Do not increase Setbacks from 
from pavement 10.2.1\1.6-9 flexibility pavement and utili ties 
and utili ties pro tects these 
in fras tructure 
elements 
7 Twice monthly 11.1.B No, except Increase fl exibili ty OK as long as trees 
inspectjon no t reqwred are far enough away 
requirement when no from planned 
active constructjon activities 
development 
Previous Amendments to the Urban Forestry Manual 
At the November 27, 2012 meeting, council adopted revisions to the Tigard D evelopment Code 
and Tigard Municipal Code to implement the Urban Forestry Code Revisions. Some of the code 
amendments required revisions to the Urban Forestry Manual for consistency purposes. An 
updated version of the Urban Forestry Manual, which incorporates the revisions from the 
November 27, 2012 meeting is provided as part o f this council packet. The revisions include: 
• Differentiation between residential and non residential requirements for the 
maintenance of trees planted with development (Urban Forestry Manual Section 
11.2); 
• 
• 
Housekeeping amendments to the tree risk assessment methodology (Urban Forestry 
Manual Section 1 and Appendix 1); and 
H ousekeeping amendment to correct the spelling of a tree's common name (Urban 
Forestry Manual Appendix 2). 
2 
Potential Amendments to the Urban Forestry Manual 
Potential Amendment 1: Increase flexibility on sheet size requirement. 
Code/Manual Section: Urban Forestry Manual Section 10, Part 1 (Urban Forestry Plan 
Standards- Tree Preservation and Removal Site Plan Requirements:) 
A. The plan shall be standard sizeD (24" x 36"), a reduced legftl kdw size (11" x 17") 
and a PDF, and include all items in part 1.B-O below. When required for clarity, the 
development impact area information in part 1.1 may be detailed separately on 
multiple plan sheets provided that all of the remaining items in part 1 are included 
for reference. Alternate sheet sizes may be allowed if approved by the cit;y manager 
or designee. 
Code/Manual Section: Urban Forestry Manual Section 10, Part 2 (Urban Forestry Plan 
Standards - Tree Canopy Site Plan Requirements:) 
A. The plan shall be standard sizeD (24" x 36"), a reduced legftl kdw size (11 " x 17") 
and PDF format, and include all items in part 2.B-O below. Alternate sheet sizes may 
be allowed if approved by the cit;y manager or designee. 
Code/Manual Section: Urban Forestry Manual Section 12, Part 3 (Street Tree Soil Volume 
Standards - Soil Volume Plan Requirements:) 
B. A standard sizeD (24" x 36"), a reduced legftl kdw size (11" x 17") and a PDF soil 
volume plan by a registered landscape architect (the project landscape architect) that 
includes all of the following elements (alternate sheet sizes may be allowed if 
approved by the cit;y manager or designee): 
Code/Manual Section: Urban Forestry Manual Section 13, Part 3 (Parking Lot Tree 
Canopy Standards- Parking Lot Tree Canopy Plan Requirements:) 
B. A standard sizeD (24" x 36"), a reduced legftl kdw size (11" x 17") and a PDF 
parking lot tree canopy plan by a registered landscape architect (the project landscape 
architect) that includes all of the following elements (alternate sheet sizes may be 
allowed if approved by the cit;y manager or designee): 
Note: Revising the term "legal" to "ledger" in the sections above corrects a scrivener's error. 
3 
Potential Amendments to the Urban Forestry Manual 
Potential Amendment 2: Increase flexibility on bar scale requirement. 
Code/Manual Section: Urban Forestry Manual Section 10, Part 1 (Urban Forestry Plan 
Standards- Tree Preservation and Removal Site Plan Requirements:) 
D. Bar scale as follows (unless otherwise approved by the city manager or designee): 
1. Less than 1.0 acres: 1" = 10' 
2. 1.0 - 5.0 acres: 1" = 20' 
3. 5.0- 20.0 acres: 1" = 50' 
4. Over 20.0 acres: 1" = 100'. 
Code/Manual Section: Urban Forestry Manual Section 10, Part 2 (Urban Forestry Plan 
Standards - Tree Canopy Site Plan Requirements:) 
D. Bar scale as follows (unless otherwise approved by the city manager or designee): 
1. Less than 1.0 acres: 1" = 1 0' 
2. 1.0 - 5.0 acres: 1" = 20' 
3. 5.0- 20.0 acres: 1" = 50' 
4. Over 20.0 acres: 1" = 100'. 
4 
Potential Amendments to the Urban Forestry Manual 
Potential Amendment 3: Do not require driplines of trees to be shown on site plans to 
scale. 
Code/Manual Section: Urban Forestry Manual Section 10, Part 1 (Urban Forestry Plan 
Standards- Tree Preservation and Removal Site Plan Requirements:) 
]. The trunk locations, driplines, assigned numbers and "X" marks when applicable 
(indicating trees proposed for removal) for the following trees within the 
development impact area and within 25 feet of the development impact area: 
1. Trees greater than or equal to 6 inch DBH; and 
2. Other trees that require a permit to remove by Title 8 and are less than 6 inch 
DBH. 
K. The trunk locations, driplines and assigned numbers for the following trees that are 
not within the development impact area: 
1. Open grown trees greater than or equal to 6 inch DBH; and 
2. Other trees that require a permit to remove by Title 8 and are less than 6 inch 
DBH. 
L. The dfiplines locations of stand grown trees greater than or equal to 6 inch DBH 
that form a contiguous tree canopy. The dflplines location of stand grown trees may 
be delineated at the outer edge of the stand. Each stand shall be assigned a number. 
Code/Manual Section: Urban Forestry Manual Section 10, Part 2 (Urban Forestry Plan 
Standards - Tree Canopy Site Plan Requirements:) 
H. The trunk locations, driplines and assigned numbers for trees to be preserved in 
parts 1.) and 1.K. Each tree on both the tree preservation and removal site plan and 
tree canopy site plan shall be assigned the same number on both plans. 
I. The dfipline locations of stand grown trees proposed for preservation greater than 
or equal to 6 inch DBH that form a contiguous tree canopy. The dfiplines location 
of stand grown trees may be delineated at the outer edge of the stand. Each stand 
shall be assigned a number. Each stand on both the tree preservation and removal 
site plan and tree canopy site plan shall be assigned the same number on both plans. 
L. The location, species, caliper (in inches for deciduous) or height (in feet for 
evergreen); and assigned numbers and depiccion of the ffiattlt'e tree canopy (in feet as 
idencified on any of the tree lists in the Urban Forestry Manual or by the city 
ffianager or designee) for all trees to be planted and maintained as open grown 
trees ... 
M. The location, species, caliper (in inches for deciduous) or height (in feet for 
evergreen); and assigned numbers and depiccion of tl~e ffiature tree canopy (in feet as 
idencified on any of the tree lists in the Urban Forestry Manual or by the city 
· or designee) for all trees to be planted and maintained as epett .s.tand grown 
5 
Potential Amendments to the Urban Forestry Manual 
trees. The species o f trees planted and maintained as stand grown trees shall be 
selected from the native tree list in the Urban Forestry Manual. The depiction of the 
mature tree canopy dripline shall be consistent with dimensions in the native tree 
list ... . 
Note: Revision o f the word "open" to the word "stand" in item M above is to correct a 
. I 
scnvener s error. 
Potential Amendment 4: Revise tree lists. 
Code/Manual Section: Urban Forestry Manual Appendices 2-6 (Street Tree List, Parking 
Lot Tree List, Columnar Tree List, Native Tree List and N uisance Tree List) 
Note: Council will need to provide staff with direction on which species to add or delete if 
they decide to revise the lists. 
6 
Potential Amendments to the Urban Forestry Manual 
Potential Amendment 5: Increase flexibility of setbacks between trees and buildings. 
Code/Manual Section: Urban Forestry Manual Section 10, Part 2 (Urban Forestry Plan 
Standards - Tree Canopy Site Plan Requirements:) 
L. ... Open grown trees shall be located as follows: 
1. Trees categorized as small stature on any of the tree lists in the Urban Forestry 
Manual or by the city manager or designee shall be spaced no closer than 15 
feet on center from other newly planted or existing trees and 10 feet from the 
face of habitable buildings. In downtown Tigard (Mixed Use Central Business 
District, MU CBD), tThe setback from the face of habitable buildings may be 
reduced if approved by the city manager or designee; 
2. Trees categorized as medium stature on any of the tree lists in the Urban 
Forestry Manual or by the city manager or designee shall be spaced no closer 
than 20 feet on center from other newly planted or existing trees and 15 feet 
from the face of habitable buildings. In downtown Tigard (Mixed Use Central 
Business District, MU CBD), tihe setback from the face of habitable 
buildings may be reduced if approved by the city manager or designee; 
3. Trees categorized as large stature on any of the tree lists in the Urban Forestry 
Manual or by the city manager or designee shall be spaced no closer than 30 
feet on center from other newly planted or existing trees and 20 feet from the 
face of habitable buildings. In downtown Tigard (Mixed Use Central Business 
Dise:ict, MU CBD), tThe setback from the face of habitable buildings may be 
reduced if approved by the city manager or designee; 
4. Trees determined by the city manager or designee to have a mature spread of 
less than 20 feet shall be considered small stature, and shall be spaced no 
closer than 15 feet on center from other newly planted or existing trees and 10 
feet from the face of habitable buildings. In downtovv·n Tigard (Mixed Use 
Central Business District, MU CBD), tihe setback from the face of habitable 
buildings may be reduced if approved by the city manager or designee; 
5. Trees categorized as small stature on any of the tree lists in the Urban Forestry 
Manual or by the city manager or designee shall not be planted with the center 
of their trunks closer than 2 feet from any hard surface paving; 
6. Trees categorized as medium stature on any of the tree lists in the Urban 
Forestry Manual or by the city manager or designee shall not be planted with 
the center of their trunks closer than 2 1/z feet from any hard surface paving; 
Note: The addition of "or by the city manager or designee" to item L.6 above is to correct a 
• I 
scnvener s error. 
M. . .. Stand grown trees shall be located as follows: 
3. Trees categorized as small stature on the native tree list in the Urban Forestry 
7 
Potential Amendments to the Urban Forestry Manual 
Manual or by the city manager or designee shall be spaced no closer than 15 
feet from the face of habitable buildings. In dO\vntown Tigard (Mixed Use 
Central Business District, MU CBD), tT he setback from the face of habitable 
buildings may be reduced if approved by the city manager or designee; 
4. Trees categorized as medium stature on the native tree list in the Urban 
Forestry Manual or by the city manager or designee shall be spaced no closer 
than 20 feet from the face of habitable buildings. In downtown Tigard (hfixed 
Use Central Business District, MU CBD), ti he setback from the face o f 
habitable buildings may be reduced if approved by the ci ty manager or 
designee; 
5. Trees categorized as large stature on the native tree list in the Urban Forestry 
Manual or by the city manager or designee shall be spaced no closer than 30 
feet from the face of habitable buildings. In dov; ntown Tigard (Mixed Use 
Central Business District, MU CBD), tT he setback from the face of habitable 
buildings may be reduced if approved by the city manager or designee; 
6. Trees categorized as small stature on the native tree list in the Urban Forestry 
Manual or by the city manager or designee shall no t be planted with the center 
o f their trunks closer than 2 feet from any hard surface paving; 
7. Trees categorized as medium stature on the native tree list in the Urban 
Forestry Manual or by the city manager or designee shall not be planted with 
the center o f their trunks closer than 2 1/z feet from any hard surface paving; 
Note: T he addition of "or by the city manager or designee" to item M.7 above is to correct a 
. I 
scnvener s error. 
8 
Potential Amendments to the Urban Forestry Manual 
Potential Amendment 6: Increase flexibility of setbacks between trees and pavement and 
utilities. 
Code/Manual Section: Urban Forestry Manual Section 10, Part 2 (Urban Forestry Plan 
Standards - Tree Canopy Site Plan Requirements:) 
L. ... Open grown trees shall be located as follows: 
5. Trees categorized as small stature on any of the tree lists in the Urban Forestry 
Manual or by the city manager or designee shall not be planted with the center 
of their trunks closer than 2 feet from any hard surface paving unless 
otherwise approved by the city manager or designee; 
6. Trees categorized as medium stature on any of the tree lists in the Urban 
Forestry Manual or by the city manager or designee shall not be planted with 
the center of their trunks closer than 2 1/ z feet from any hard surface paving 
unless otherwise approved by the city manager or designee; 
7. Trees categorized as large stature on any of the tree lists in the Urban Forestry 
Manual or by the city manager or designee shall not be planted with the center 
of their trunks closer than 3 feet from any hard surface paving unless 
otherwise approved by the city manager or designee; 
8. Where there are overhead utility lines, the tree species selected shall be of a 
type which, at full maturity, will not interfere with the lines unless otherwise 
approved by the city manager or designee; and 
Note: The addition of "or by the city manager or designee" to item L.6 above is to correct a 
scrivener's error. 
M. . .. Stand grown trees shall be located as follows: 
6. Trees categorized as small stature on the native tree list in the Urban Forestry 
Manual or by the city manager or designee shall not be planted with the center 
of their trunks closer than 2 feet from any hard surface paving .unkss 
otherwise approved by the city manager or designee; 
7. Trees categorized as medium stature on the native tree list in the Urban 
Forestry Manual or by the city manager or designee shall not be planted with 
the center of their trunks closer than 2 1/ z feet from any hard surface paving 
unless otherwise approved by the city manager or designee; 
8. Trees categorized as large stature on the native tree list in the Urban Forestry 
Manual or by the city manager or designee shall not be planted with the center 
of their trunks closer than 3 feet from any hard surface paving unless 
otherwise approved by the city manager or designee; 
9. Where there are overhead utility lines, the tree species selected shall be of a 
type which, at full matur!tL will not interfere with the lines unless otherwise 
9 
Potential Amendments to the Urban Forestry Manual 
approved by the city manager or designee; and 
Note: T he addition o f "or by the city m anager or designee" to item M.7 above is to correct a 
. ' scnvener s error. 
Potential Amendment 7: Increase flexibility o f the biweekly inspection requirements. 
Code/Manual Section: Urban Forestry Manual Section 11 , Part 1 (Urban Forestry Plan 
Implementation Standards - Inspection Requirements:) 
B. Following the completion o f item a above, the project arborist or landscape architect 
shall perform bimonthly semimonthly (twice monthly) site inspections for tree 
protection measures during periods o f active site development and construction, 
document compliance / non-compliance with the urban forestry plan and send 
written verification with a signature o f approval directly to the city manager or 
designee within one week of the site inspection. T he frequency of site inspections 
may be decreased if approved by the city m anager or designee. 
E. Prior to final building inspection for any lo t or tract with an aet:We urban forestry 
plan that is still in effect, the project arborist or landscape architect shall perform a 
site inspection, document compliance/ non-compliance with the urban forestry plan 
and send written verification with a signature o f approval to the city m anager or 
designee. 
N ote: T he revision of the word "active" to the term "in effect" in item E above corrects a 
scrivener' s errors and ensures consistency in terminology used throughout the code and 
manual. 
10 
Except of January 22, 2013 City Council meeting minutes 
A portion of the public hearing and council consideration: of the Administrative Rules associated 
with the Urban Forestry Code Revisions Project and the revisions to the proposed Citywide Master 
Fees and Charges Schedule: 
Council discussion and deliberation: 
0 
In response to a question from Mayor Cook- Associate Planner D aniels distributed a summary of 
changes to further clarify changes to the mas ter fees and charges schedule. Shows each fee being 
m odified and whether it is being added or deleted and a description o f the fee. While there are more 
fees; the costs applying the fee will not m ean the costs to develop will be more since the am ount o f 
the fees for specific actions are less than what was being charged under the existing requirements. 
In response to a question from Councilor H enderson an arborist, in some circumstances, must be 
hired; however, this is a requirem ent in the existing code also, including when a developer creates a 
partition (2 or 3 lo ts) or a subdivision. N o arborist is requu:ed for an addition to a single-family 
hom e. 
In response to a question from Councilor Woodard about a tree es tablishment bond, Associate 
Planner D aniels advised that the city currently has such a bond, but it is not part of the fee schedule. 
Staff is proposing to m ake these charges a part o f the fee schedule so everyone knows what to 
expect. T he m oney paid for the bonds is refunded when the developer has demonstrated the 
requirements were met. 
Councilor Woodard asked about urban forestry inventory fees. Consultant Prager said this is a new 
fee. T his fee would contribute to building the tree inventory so people can more easily identify trees 
that are protected on their property. In response to a comment by Councilor Snider, Consultant 
Prager explained that the council, by adoption o f the Comprehensive Plan / Mas ter Plan , directed 
that the city should provide a publicly accessible tree inventory so people could find this information 
more easily. Councilor Woodard noted some concerns about whether this fee will end up costing 
developers and property owners more than anticipated; he indicated he felt more comfortable with 
letting this proceed because this can be reviewed when needed; i.e., annually. 
Principal Planner McG uire suggested that one way to look at the costs associated with establishing a 
tree inventory: Currently, if a hom eowner knows that some trees on their lo t might be protected, 
they must com e to the Permit Center to ask staff to help them identify the trees. Staff then must 
research records, which might be in a paper or electronic format. Instead of taking staff time to do 
this research, this inspection could be done at the beginning when subdivisions and plans are being 
approved by simply referri11g to the city's G IS system. This fee offsets inputting the information · 
into the GIS system . City Manager Wine, in response to a question from Councilor Snider, said the 
requirement to build a tree inventory is new and a developer applicant is not paying for staff 
research time now. 
Responding to a question from Council President Buehner, staff confirmed during the application 
process that if a tree is identified to remain on a piece o f property, then the developer/ applicant 
must pay $137 to place the tree within the GIS system. 
Councilor Henderson commented on how the City o f T igard compares itself to other cities - should 
this be something we should do? Associate Planner Daniels said the Planning Commission 
requested this review be done when it was considering this matter; Tigard is comparable with regard 
to the fees being imposed. Councilor Henderson said he thinks it's often a good idea to look to see 
how the city compares to other jurisdictions, he thinks we could always strive to do better regardless. 
0 Motion by Councilor Snider, seconded by Councilor Buehner, to approve the administrative 
rules proposed in the Urban Forestry Manual. 
> Note: Mayor closed the public hearing prior to the City Council taking a vote on the motion . 
The motion was approved by a unanimous vote of City Council present. 
Mayor Cook Yes 
Council President Henderson Yes 
Councilor Buehner Yes 
Councilor Snider Yes 
Councilor Woodard Yes 
Associate Planner Daniels referred to the potential amendments to the called out in the staff report and 
documentation submitted to the council for its consideration of the proposed administrative rules. 
Clarification was made that the City Council is directing the City Manager to approve the administrative 
rules. City A ttorney Bennett referred to the motion above on the administrative rules. This motion 
was made and seconded and the City Council approved that motion. By approving the motion, the 
City Council was directing the City Manager to approve the administrative rules. This action has been 
taken. The administrative rules proposed to the City Council were based upon the staff memorandum. 
City Attorney Bennett said he would read that to mean the Council has directed the City Manager to 
approve the manual, consistent with the staff report presented to the City Council tonight. 
City Attorney Bennett said, "To make it clear . . . you direct the City Manager to implement the 
administrative rules proposed in the Urban Forestry Manual, based upon the staff report presented to 
you tonight and the modifications that were included that staff report." Council members indicated this 
was its direction. 
City Attorney recommended that the City Cow1cil entertain a new motion to clarify the decision made 
by council earlier to direct the city manager. 
Motion by Councilor Woodard, seconded by Councilor Buehner, that the City Manager is hereby 
directed to approve the administrative tules proposed in the Urban Forestry Manual, consistent with the 
recommended changes in the staff report dated January 22, 2013. 
The motion was approved by a unanimous vote of City Council present. 
Mayor Cook Yes 
Council President Henderson Yes 
Councilor Buehner 
Councilor Snider 
Councilor Woodard 
Yes 
Yes 
Yes 
0 Consideration of a resolution to amend the citywide mas ter fees and charges schedule. 
Councilor Buehner no ted that the City Council usually considers the mas ter fees and charges scheduled 
during the consideration of d1e budget each year. City Manager Wine advised d1ese charges before ilie 
City Council this evening will be included in the schedule submitted to ilie City Council during d1e FY 
2014 budget adoption process. 
Motion by Councilor Buehner, seconded by Councilor Woodard, to adopt Resolution No. 13-03, a 
resolution to amend the Citywide Master Fees and Charges Schedule as Adopted by Resolution No. 
12-22 to institute new and revised fees necessary to in1plement the Urban Forestry Code Revisions 
Projec t. 
T he motion was approved by a unanimous vote of City Council present. 
Mayor Cook Yes 
Council President Henderson Yes 
Councilor Buehner 
Councilor Snider 
Councilor Woodard 
Yes 
Yes 
Yes 
City of Tigard 
COMMUNI1Y DEVELOPMENT D EPARTMEN T 
13125 SW Hall Blvd., Tigard, OR 97223 
W\VW. tigard-or.gov / trees I 
Volume IV: Table of Contents 
Organization of the Urban Forestry Code Revisions Documents 
Urban Forestry Manual 
Table of 
Section 1 - Hazard Tree Evaluation and Abatement Procedure 
Section 2 - Street Tree Planting and Maintenance Standards 
Sectio n 3 - Street Tree Removal Standards 
Section 4 - Median Tree Planting and Maintenance Standards 
Section 5 - Median Tree Removal Standards 
1 
5 
9 
11 
15 
Section 6- Sensitive Lands Tree Removal and Replacement Standards .... ............................ ............ . 23 
Section 7- Development Tree Removal and Replacement Standards 
Section 8- Urban Forestry Fund Tree Removal and Replacement Standards ... .. ..... ... ....... ... .. ... ...... 31 
Section 9- Heritage Tree Designation and Removal Standards 
Section 10 - Urban Forestry Plan Standards 
Section 11 -Urban Forestry Plan Implementation Standards 
Section 12- Street Tree Soil Volume Standards 
Section 13 - Parking Lot Tree Canopy Standards 
Appendices 
Organization of the U rban Forestry Code Revisions D ocuments 
T he Urban Fores try Code Revisions project is presented in five volumes. Volume I provides the 
project overview and describes the process used to develop all o f the elements. Volume II is the 
land use elements o f the code, and Volume III the non land use elements. Volume IV contains the 
Urban Fores try Manual. Volume V contains technical reports and research that contributed to the 
code revisions along with details o f the public input and deliberations to date. 
Volume I I Project Overview 
Project Overview includes the following sectio ns: 
• Project Introduction 
• Overview o f K ey E lements 
• K ey Element Summaries 
o Urban Forestry Standards for Development 
o Tree Grove Preservation Incentives 
o Tree Permit Requirements 
o Hazard Trees 
o Urban Fores try Manual 
Appendix A includes additional detail about the information used to shape the Urban 
Fores try Code Revisions Project, and includes the following sections: 
• Process summary 
• Summary o f Community Ideas and Concerns 
• Summary o f Planning Commission D eliberations 
• E xisting Conditions 
Volume II I Land Use Elements 
Community Development Code (Title 18) is the Planning Commission's recommended 
draft o f the D evelopment Code. T his section includes commentary on the amendments. 
Peer Review demonstrates how the Planning Commission's recommended draft o f the 
D evelopment Code and Urban Forestry Manual will work in application. 
Tree Grove ESEE Analysis is a report that addresses Statewide Planning GoalS - Natural 
Resources requirements for the preservation o f Significant Tree G roves. 
Staff Report and findings includes the staff recommendation for approval o f the land use 
elements (Title 18 and the Comprehensive Plan Amendment) and the findings that 
demo nstrate the land use elements meet the necessary approval criteria. 
City of Tigard Urban Forestry Code Re,·isions I Volume 1\' I 1 
Volume III I Non Land Use Elements 
Tigard Municipal Code is the staff proposed draft o f the Municipal Code (Title 8 and 
o ther Municipal Code titles) . This section includes commentary on the amendments. 
Volume IV I Urban Forestry Manual (Administrative Rules) 
Urban Forestry Manual consists o f administrative rules that implement the technical 
details o f the urban fores try related code provisions in Title 8, Title 18 and o ther applicable 
titles in the Tigard Municipal Code. 
Volume V I Additional Background Materials 
Planning Commission Deliberations details Planning Commission discussion and 
decisions during the public hearing process. 
Amendment Requests Document for the Planning Commission lists code amendment 
reguests received in response to the first Planning Commission public hearing and sta ff 
responses. 
Outstanding Issues for the Urban Forestry Code Revisions includes additional 
information on the outs tanding issues that were further deliberated by the Planning 
Commission before making their final recommendation to City Council on May 7, 2012. 
Log of Input lists the input received and any code changes from the las t meeting o f the 
CAC to the staff proposed draft o f the U rban Fores try Code Revisions to Planning 
Commission. 
CAC Guiding Principles includes the consensus view o f the Citizens Advisory Committee 
(CAC) developed to help guide the legislative adoption process. 
Tree Values includes information and current research on the environmental, economic, 
social and aesthetic benefits o f trees. 
Canopy Standards explains the reasons fo r adopting tree canopy cover reguirem ents as 
well as the m ethods used to arrive at the reguirements . 
Soil volume details research about the soil volume reguired to support a mature tree 
canopy. 
Tree Canopy Fee discusses research used to develop a sguare foot value for tree canopy. 
Regulatory Comparison is an excerpted report prepared by Metro and the Audubon 
Society that summarizes and compares regional urban fores try program s and regulations. 
Urban Forestry Master Plan is the City o f Tigard 's recommended plan for achieving the 
urban fores try goals in the Comprehensive Plan. 
CitY of Tigard Urban l'nrcsrry Code Rn isions I \ 'olumc 1\ ' I 2 
City offigard 
URBAN FORESTRY MANUAL 
Introduction 
T he Urban Fores try Manual consists o f administrative rules that implement the details of the urban 
forestry related code provisions in Title 8, Title 18 and o ther applicable titles in the Tigard Municipal 
Code. 
T he city manager or designee has the authori ty to amend the Urban Fores try Manual pursuant with 
the provisions in Chapter 2.04 of the Tigard Municipal Code. T he city manager or designee is 
authorized to administer the Urban Fores try Manual. 
Ciry of Tigard Urban Fo restry Code Rc,·isio m I \'o lumc 1\' I 3 

TABLE OF CONTENTS 
Section 1 ...................................... .. Hazard Tree Evaluation and Abatement Procedure 
Section 2 ............................................ Street Tree Planting and Maintenance Standards 
Section 3 ......................................................................... Street Tree Removal Standards 
Section 4 ......................................... Median Tree Planting and Maintenance Standards 
Section 5 .. ................................................................... Median Tree Removal Standards 
Section 6 ........................... Sensitive Lands Tree Removal and Replacement Standards 
Section 7 ............................... Development Tree Removal and Replacement Standards 
Section 8 .................. Urban Forestry Fund Tree Removal and Replacement Standards 
Section 9 ....................................... Heritage Tree Designation and Removal Standards 
Section 10 ....................................................................... Urban Forestry Plan Standards 
Section 11 ............................................ Urban Forestry Plan Implementation Standards 
Section 12 ................................................................. Street Tree Soil Volume Standards 
Section 13 .............................................................. Parking Lot Tree Canopy Standards 
City o f Tigard Urban Forestry Code Rc,·isions I \'o lumc 1\ ' I 5 

APPENDICES 
Appendix 1 ......................................................................... Tree Risk Assessment Form 
Appendix 2 .............................................................................................. Street Tree List 
Appendix 3 .................................................................................... Parking Lot Tree List 
Appendix 4 ....................................................................................... Columnar Tree List 
Appendix 5 ............................................................................................ Native Tree List 
Appendix 6 ....................................................................................... Nuisance Tree List 
Appendix 7 ..................................... Example Tree Preservation and Removal Site Plan 
Appendix 8 ................................................................... Example Tree Canopy Site Plan 
Appendix 9 .................................................... Example Supplemental Report Template 
Appendix 10 ............................... Example Tree Canopy Site Plan for an Individual Lot 
Appendix 11 ................................... Example Soil Volume Calculations for Street Trees 
Appendix 12 .......................................................................... Example Soil Volume Plan 
Appendix 13 ................................................ Example Soil Volume Plan for a Single Lot 
Appendix 14 .................................... Example Covered Soil Volume Plan Drawings and 
Example Covered Soil Specifications for Street Trees 
Appendix 15 ......................... Example Soil Volume Calculations for Parking Lot Trees 
Appendix 16 .................................................... Example Parking Lot Tree Canopy Plan 
Appendix 17 .................................... Example Covered Soil Volume Plan Drawings and 
Example Covered Soil Specifications for Parking Lot Trees 
Appendix 18 ................................. Example Parking Lot that Meets the 30% Minimum 
Canopy Cover Requirement 
City of Tigard Urban Forestry Code Re,·isions I Volume IV I 7 

Section 1 - Hazard Tree Evaluation and Abatement Procedure 
P art 1. Informal Reconciliation: 
I f in terpersonal communication is not feasible or is unsuccess ful, the 
claimant shall contact the respondent by concurrendy sending a 
regular and certified letter that explains the reasons they believe there 
is a hazard tree on the respondent's property, demonstrates how the 
claimant's life, limb or property has the potential to be impacted by 
said tree, and offers to negotiate a solution that is in compliance with 
all applicable rules and regulations either direcdy or through a third 
party mediator. T he claimant is encouraged to support their claim 
with documentation by a tree risk assessor. T he respondent shall have 
seven calendar days or less from receipt o f the certified letter or 14 
calendar days or less from the postmarked date o f the regular letter 
(whichever is sooner) to respond to the claimant's proposal in writing 
by concurrent regular and certified mail. In order to become eligible 
for formal reconciliation, the claimant's letter shall cite Tigard 
Municipal Code sections 8.06.020 and 8.06 .030, explain the 
respondent's written response deadlines and include all o f the other 
reguired elements listed above. 
Part 2. Formal Reconciliation: 
If the results o f informal reconciliation are no t acceptable to the 
claimant or there has been no response for 21 calendar days or more 
since the claimant sent the concurrent regular and certified letters, the 
claimant may seek resolution through formal reconciliation by 
completing a hazard tree dispute resolution application, paying a 
deposit for all applicable hazard tree dispute resolution fees and 
providing the city all documentation o f informal reconciliation 
including but not limited to any letters to and from the responden t, 
proof o f certified mail delivery and proof o f certified mail receipt (if 
available). 
The city shall use all readily available tools and technology when 
assigning the hazard tree owner or responsible party as defined in 
Tigard Municipal Code Chapter 8.02. If the city determines that the 
claimant's previous correspondence was with the incorrect 
responden t, then the claimant shall be reguired to complete the 
previous steps o f the hazard tree evaluation and abatement procedure 
with the correct respondent before proceeding with formal 
reconciliation. If the claimant or respondent disagrees with the city's 
assignment o f the hazard tree owner or responsible party, the city shall 
be presented a land survey by a professional land surveyor that 
demonstrates the location o f the tree in gues tion in relation to 
property lines within all listed deadlines in order for the city to 
consider a reassignment of the hazard tree owner or responsible party. 
Section 1- Hazard Tree Eva lu atio n and Abatement Pro ced ur e 
City of Tigard U rban Forestry Manual 
-
-
City of Tigard Urban Forestry Code Rc,·isions I Volume IV I 9 
Notes: 
Sec Master Fees and 
Charges Schedule for 
current fees 
- --
Page 1-1 
-- - ----
Note~: 
Sec , \ ppcndix 1 for 
Tree Ri' k 
1\~~e~sn1 c t1t I <'o rn1 
P age 1-2 
Within seven calendar days o f receipt o f all the reguired application materials, 
the city shall gain access to the respondent's property either voluntarily or with 
a warrant pursuant to Chapter 1.16 o f the Tigard Municipal Code, conduct a 
tree ri sk assessment by a tree risk assessor using the tree risk assessment 
methodology in Appendix 1 o f the U rban Fores try Manual, determine if the 
definition o f hazard tree in Tigard Municipal Code Chapter 8.02 has been met 
and, if necessary, prescribe hazard tree abatement as defined in Tigard 
Municipal Code Chapter 8.02. 
If the city determines the definition o f hazard tree has been met, the city shall 
send a concurrent regular and certified letter to the respondent, explain that the 
definition o f hazard tree has been m et, explain the reguired hazard tree 
abatement procedures and reguire that hazard tree abatement be completed in 
seven calendar days or less from receipt o f the certified letter or 14 calendar 
days or less from the mailing date o f the regular letter (whichever is less). T he 
city shall also bill the respondent for all applicable hazard tree dispute 
resolution fees, and re fund the claimant previously deposited hazard tree 
dispute resolution fees. 
If the respo ndent fails to complete the hazard tree abatement within the 
reguired timeframe, the city shall gain access to the property either voluntarily 
or with a warrant, abate the hazard , bill the respondent for the cos t o f 
abatement including administrative cos ts or place a lien on the property fo r the 
cost o f abatement including administrative cos ts pursuant to Chapter 1.16 o f 
the T igard Municipal Code. 
If the city determines the definition o f hazard tree has no t been met, the city 
shall send a concurrent regular and certified letter to bo th the claimant and 
respondent explaining that the definition o f hazard tree has no t been met and 
close the case. 
END OF SECTION 
Sec ti on 1- H aza rd T r ee Eva lu a ti o n a nd A b a t e m e n t Pr oce dur e 
Ci t y o f T i ga rd U rb a n Fo r est r y M a nu a l 
City oiTigard Urban h >rc,trr Code I<<Ti, iom I \ 'olumc 1\' I Ill 
P art 1. 
A. 
B. 
c. 
D. 
Section 2- Street Tree Planting and M aintenance Standards 
Street Tree Planting Standards: 
Street trees shall be planted in a manner consistent with tree care 
industry standards. 
Street trees shall have a minimum caliper of 1 1/2 inches at the time of 
planting. 
Stree t tree species shall be from the street tree list, unless o therwise 
approved by the city manager or designee. 
Street tree species shall be appropriate for the planting environment as 
determined by the city manager or designee and seek to achieve a 
balance of the following: 
1. Consistency with previously approved street tree plans given 
space constraints for roo ts and branches at maturity; 
2. Compatibili ty wi th space constrain ts for roots and branches at 
maturi ty; 
3. Providing adequate species diversity citywide and reasonable 
resistance to pests and diseases; and 
4. Consideration o f the objectives of the current street tree 
planting proposal. 
E. Street trees shall be provided adequate spacing from new and exis ting 
trees according to the following standards wherever possible: 
1. Street trees ca tegorized as small stature on the street tree list or 
by the city manager or designee shall be spaced no greater than 
20 feet on center and not closer than 15 feet on center from 
other newly planted street trees or any existing tree that has 
been in the ground for over three years; 
2. Street trees categorized as medium stature on the street tree list 
or by the city manager or designee shall be spaced no grea ter 
than 30 feet on center and no t closer than 20 feet on center 
from other newly planted street trees or any existing tree that 
has been in the ground for over three years; 
3. Street trees ca tegorized as large stature on the street tree list or 
by the city manager or designee shall be spaced no greater than 
40 feet on center and not closer than 30 feet on center from 
o ther newly planted street trees or any existing tree that has 
been in the ground for over three years; and 
4. A ny tree determined by the city manager or designee to have a 
mature spread o f less than 20 feet shall be considered a small 
stature tree, and spaced accordingly when used as a street tree. 
F. Street trees shall be placed according to the following standards: 
Sec ti o n 2 - S tr ee t Tree Pl a ntin g a nd M a int e nan ce St a nd a rd s 
Cit y o f Ti ga rd U rb a n F o r es tr y Manu a l 
Ciry of Tigard Urban Forestry Code Rc,·isions I Volume IV I 11 
Notes: 
Sec 1\ ppcndix 2 for 
Street Tree J .ist 
Page 2-1 
N ote>: 
Sec Cmk Section 
8.08 and i\ lanual 
Section 3 for Street 
T ree Removal 
Standard > 
Sec [\ Jaster l'ccs and 
Charges Schedule for 
currcn t fees 
P age 2-2 
1. 
2. 
3. 
4. 
5. 
6. 
7. 
Street trees categorized as small stature on the street tree list 
or by the city manager or designee shall no t be planted with 
the center o f their trunks closer than 2 fee t from any hard 
surface paving; 
Street trees categorized as medium stature on the street tree 
list o r by the city manager or designee shall no t be planted 
with the center o f their trunks closer than 2 % feet from any 
hard surface paving; 
Street trees categorized as large stature on the stree t tree list 
or by the city manager or designee shall no t be plan ted with 
the center o f their trunks closer than 3 feet from any hard 
surface paving; 
Not closer than 4 fee t on center from any fire hydrant, utility 
box or utility pole; 
Not closer than 2 feet on center from any underground 
utili ty; 
Not closer than 10 feet on center from a street light standard; 
Not closer than 20 feet from a street right o f way corner as 
determined by the city manager o r designee. T he city 
manager or des ignee may require a greater or lesser co rner 
setback based on an analysis o f traffic and pedes trian sa fety 
impacts; 
8. \X!here there are overhead utili ty lines, the street tree species 
selected shall be o f a type which, at full maturi ty, will no t 
interfere with the lines; and 
9. A ny other standards found by the city manager or designee to 
be relevant in order to protec t public sa fe ty and public o r 
private property . 
G. Root barriers shall be installed according to the manufac turer's 
specifications when a stree t tree is planted within 5 feet o f any hard 
surface paving o r utility box, o r as o therwise required by the city 
eng111eer. 
H . Street trees planted prior to the adoption o f the most current version 
o f the street tree planting standards shall be exempt from the most 
I. 
current version o f the street tree planting standards. H owever, the 
most current version o f the street tree maintenance standards and the 
most current version o f the street tree removal standards shall apply. 
If street tree planting is required by ano ther sec tion o f the U rban 
Forestry Manual or Tigard Municipal Code, the city manager o r 
designee may allow for an " in lieu o f planting fee" equivalent to the 
city's cos t to plant a stree t tree per the standards in Sectio n 2, part 1 o f 
the U rban Fores try Manual and maintain a street tree per the standards 
in Sec tion 2, part 2 o f the Urban Fores try Manual fo r a period o f three 
years after planting. Payment o f an in lieu o f planting fee shall sa ti sfy 
the street tree planting requirement. 
Sec ti o n 2 - S tr eet T r ee Pl a ntin g a nd M a int e n a n ce S t a nd a rd s 
C it y o f T i ga rd Ur b a n Fo re st r y M a nu a l 
City of Tigard Urban h >rcstry Code Rc,·isions I \ 'o lumc 1\ ' I 12 
Part 2. Street Tree Maintenance Standards: 
A. 
B. 
Street trees shall be maintained in a manner consistent with tree care 
industry standards. 
Street trees shall be maintained in a manner that does not impede 
public street or sidewalk traffic consistent with the specifications in 
section 7.40.060A o f the Tigard Municipal Code including: 
1. 8 feet of clearance above public sidewalks; 
2. 13 feet o f clearance above public local and neighborhood 
streets; 
3. 15 feet o f clearance above public collector streets; and 
4. 18 fee t o f clearance above public arterial streets. 
C. Street trees shall be maintained so as not to become hazard trees as 
defined in Chapter 8.02 o f the Tigard Municipal Code. 
END OF SECTION 
Sec ti o n 2 - S tr ee t Tr ee Pl a ntin g and M a int e nan ce Stand a rd s 
Cit y o f Ti ga rd U rban F o re s tr y M a nu a l 
City o f Tigard Urban Forestry Code Re,·isions I Volume I\' I 13 
Norcs: 
Page 2-3 
.~· 
--
Section 3- Street T ree Rem oval Standards 
P art 1. Street Tree Removal Standards : 
A. Street trees shall be removed in a manner consistent with tree care 
industry standards. 
B. The city manager or designee shall approve the removal of a street 
tree if any one of the following criteria are met: 
1. The tree is a "hazard tree" as defined in Chapter 8.02 and 
" hazard tree abatement" as defined in Chapter 8.02 cannot be 
completed in a manner that results in tree retention consistent 
with tree care industry standards. 
2. The tree is dead. 
3. The tree is in an advanced state of decline with insufficient live 
foliage, branches, roots or other tissue to sustain life. 
4. The tree is infested with pests or diseases that if left untreated 
will cause the tree to die, enter an advanced state of decline or 
cause o ther trees to die or enter an advanced state o f decline. 
5. The tree has sustained physical damage that will cause the tree 
to die or enter an advanced state of decline. If the physical 
damage was caused by a person in violation of Chapter 8.08 of 
the Tigard Municipal Code, the enforcement process outlined 
in Section 8.02.030 shall be completed prior to approval. 
Notes: 
6. T he tree is listed on the nuisance tree list. I Sec 1\ppendix 6 for 
7. T he tree location is such that it would not meet all of the street N uisance Tree List 
tree planting standards in Section 2, parts 1E and 1F of the 
Urban Forestry Manual if it were a newly planted tree. 
8. The tree roots are causing damage to paved surfaces, 
infras tructure, utilities, buildings or o ther parts of the built 
environment. 
9. The tree location conflicts with areas of public stree t widening, 
construction or extension as shown in the Transportation 
System Plan. 
10. Tree removal is required for the purposes of an approved 
building or land use permit, utili ty or infrastructure installation 
or utility or infrastructure repair. 
11. The tree is recommended for removal by a designated fire 
marshal for Tualatin Valley Fire and Rescue because it presents 
a significant fire risk to habitable structures or limits emergency 
access for rescue workers, and the risk or access issue cannot be 
abated through pruning or other means that results in tree 
-
retention. 
Sec ti o n 3 - S tr ee t T r ee R e m ova l S t a nd a rd s 
C it y o f T i ga rd U rb a n Fo r es tr y M a nu a l 
City of Tigard Urban Forestry Code Revisions I Volume IV 1 15 
Page 3-1 
N otes: 
c. 
D. 
Page 3-2 
12. The tree is part of a stand of trees, and a certified arborist o r 
certified forester determines that thinning o f interior trees 
within the stand of trees is necessary for overall stand health, 
the thinning will result in no less than 80 percent canopy cover 
at maturity fo r the area to be thinned, and that thinning o f non-
native trees is maximized prior to thinning o f native trees. 
U nless removed fo r thinning purposes (part 1.B.11above) the city 
manager o r designee shall condition the removal o f a street tree upon 
the planting of a replacement tree in accordance with the Street Tree 
Planting Standards in Section 2, part 1 of the Urban Forestry Manual. 
T he city manager or designee may consider existing trees as 
replacement trees if they meet all applicable species, size, condition and 
loca tion requirements in Section 2, part 1 and were no t already required 
to be planted or preserved by the Tigard Municipal Code. 
If the Street Tree Planting Standards in Section 2, part 1 o f the Urban 
Forestry Manual preclude replanting within the same right of way 
abutting on, fronting on or adjacent to the property as the tree was 
removed or on private property within 6 feet o f the same right of way 
as the tree that was removed, the applicant shall be exempt from 
planting a replacement tree . 
• w.-
END OF SECTION 
Sec ti o n 3- Stree t Tr ee R e m ova l S t a nd a rd s 
C i ty o f Ti g ard U rb a n Fo r es tr y M a nu a l 
Citr of T igard Urban l:ore>try Code l(e,·i>ion> I Volume 1\' I 1(, 
Section 4 - Median Tree Planting and M ainten ance Standards 
Part 1. 
A. 
B. 
c. 
D . 
Median Tree Planting Standards: 
Median trees shall be planted in a manner consistent with tree care 
industry standards. 
Median trees shall have a minimum caliper of 1 1/z inches at the time 
o f planting. 
Median tree species shall be from the street tree list, unless otherwise 
approved by the city manager or designee. 
Median tree species shall be appropriate for the planting environment 
as determined by the city manager or designee and seek to achieve a 
balance of the following: 
1. Consistency with previously approved median tree plans given 
space constraints for roo ts and branches at maturi ty; 
2. Compatibili ty wi th space constraints for roots and branches at 
maturi ty; 
3. Providing adequate species diversity citywide and reasonable 
resis tance to pes ts and diseases; and 
4. Consideration o f the objectives of the current median tree 
planting proposal. 
E. Median trees shall be provided adequate spacing from new and 
exis ting trees according to the following standards wherever possible: 
1. Median trees categorized as small sta ture on the street tree list 
or by the city manager or designee shall be spaced no greater 
than 20 feet on center and not closer than 15 feet on center 
from other newly planted median trees or any existing tree that 
has been in the ground for over three years; 
2. Median trees categorized as medium stature on the street tree 
list or by the city manager or designee shall be spaced no 
greater than 30 feet on center and not closer than 20 feet o n 
center from other newly planted median trees or any exis ting 
tree that has been in the ground for over three years; 
3. Median trees categorized as large stature on the street tree list 
or by the city manager or designee shall be spaced no greater 
than 40 feet on center and not closer than 30 feet on center 
from o ther newly planted median trees or any existing tree that 
has been in the ground for over three years; and 
4. Any tree determined by the city manager or designee to have a 
mature spread of less than 20 feet shall be considered a small 
stature tree, and spaced accordingly when used as a median 
tree. 
Sec ti o n 4- M e di a n T r ee Pl a n t in g a nd M a int e n a n ce S t a nd a rd s 
C it y o f Tiga rd U r ba n Fo r es tr y M a nu a l 
Ci1y o f Tigard Urban Forestry Code Rc,·isions I \'olume IV 1 17 
Notes: 
Sec i\ ppendix 2 for 
Street Tree List 
Page 4-1 
Norc': 
Sec Code S<.:ction 
8.08 and Manual 
Section 5 for [\ led ian 
Tree Removal 
Standard ' 
Page 4-2 
F. Median trees shall be placed according to the following standards: 
1. Median trees ca tegorized as small stature o n the stree t tree list 
or by the city manager or designee shall not be planted with the 
center o f their trunks closer than 2 feet fro m any hard surface 
paving; 
2. Median trees ca tegorized as medium stature on the street tree 
list or by the city manager or designee shall not be planted with 
the center of their trunks closer than 2 1/2 feet fro m any hard 
surface paving; 
3. Median trees categorized as large stature on the street tree list 
or by the city manager or designee shall not be planted with the 
cen ter o f their trunks closer than 3 feet from any hard surface 
pavmg; 
4. Not closer than 4 feet on center from any fire hydrant, utili ty 
box or utility pole; 
5. Not closer than 2 feet on center from any underground utility; 
6. Not closer than 10 feet on cen ter from a street ligh t standard; 
7. Not closer than 20 feet fro m a street righ t of way corner as 
determined by the city manager or designee. T he city manager 
or designee may require a grea ter or lesser corner setback based 
on an analysis o f traffic and pedestrian sa fety impac ts; 
8. \\!here there are overhead utili ty lines, the median tree species 
selec ted shall be o f a type which, at full maturity, will not 
interfere with the lines; and 
9. A ny o ther standards found by the city manager or designee to 
be relevant in o rder to protect public sa fety and public or 
priva te property. 
G. Root barriers shall be installed according to the manu facturer's 
specifications when a street tree is planted within 5 feet of any hard 
surface paving or utili ty box, or as o therwise required by the city 
H. 
I. 
engineer. 
Median trees planted prior to the adoption of the m ost curren t version 
of the Median Tree Planting Standards shall be exempt from the most 
current version of the Median T ree Planting Standards. However, the 
most curren t version of the Median T ree Maintenance Standards and 
the most curren t version of the Median Tree Removal Standards shall 
apply. 
If median tree plan ting is required by another section of the U rban 
Forestry Manual or T igard Municipal Code, the city manager or 
designee may allow for an "in lieu of planting fee" equivalen t to the 
city's cost to plan t a median tree per the standards in Section 4, part 1 
of the Urban Forestry Manual and main tain a street tree per the 
standards in Section 4, part 2 of the Urban Forestry Manual for a 
period o f three years after planting. Payment of an in lieu of planting 
fee shall sa tisfy the median tree planting requirem ent. 
Sec ti o n 4- M e d ia n T r ee P la ntin g a nd M a int e n a n ce S t a nd a rd s 
C it y o f Tiga rd U rb a n Fo r est r y M a nu a l 
City o f T igard Urban l'orcstry Code Rc1·isiuns I \'olume 1\' I I H 
Part 2. Median Tree Maintenance Standards: 1 N otes: 
A. Median trees shall be maintained in a manner consistent with tree care 
industry standards. 
B. Median trees shall be maintained in a manner that does not impede 
public street or sidewalk traffic consistent with the specifications in 
section 7.40.060A of the Tigard Municipal Code including: 
1. 8 feet of clearance above public sidewalks; 
2. 13 feet of clearance above public local and neighborhood 
streets; 
3. 15 feet o f clearance above public collector streets; and 
4. 18 feet o f clearance above public arterial streets. 
C. Median trees shall be maintained so as not to become hazard trees as 
defined in Chapter 8.02 of the Tigard Municipal Code. 
END OF SECTION 
Sec ti o n 4 - M e di a n T r ee Pl a ntin g and M a int e nanc e St a nd a rd s 
Cit y o f T iga rd U rb a n F o re s tr y Manu a l 
City o f Tigard Urban )."orcstry Code Rc,·isions I Vo lume IV j 19 
Page 4-3 
"' 
Section 5- M edian Tree R em oval Standards 
Part 1. M edian Tree Rem oval Standards : 
A . Median trees shall be removed in a manner consistent with tree care 
industry standards. 
B. T he city manager or designee shall approve the removal o f a median 
tree if any one o f the following criteria are met: 
1. T he tree is a "hazard tree" as defined in Chapter 8.02 and 
" hazard tree abatement" as defined in Chapter 8.02 cannot be 
completed in a manner that results in tree retention consistent 
with tree care industry standards. 
2. The tree is dead. 
3. The tree is in an advanced state o f decline with insufficient live 
foliage, branches, roots or other tissue to sustain life. 
4. The tree is infes ted with pes ts or diseases that if left untreated 
will cause the tree to die, enter an advanced state o f decline or 
cause other trees to die or enter an advanced state o f decline. 
5. The tree has sustained physical damage that will cause the tree 
to die or enter an advanced state of decline. If the physical 
damage was caused by a person in violation o f Chapter 8.08 o f 
the Tigard Municipal Code, the enforcement process outlined 
in Section 8.02.030 shall be completed prior to approval. 
N otes: 
6. The tree is listed on the nuisance tree list. I Sec Appendix 6 for 
7. The tree location is such that it would not meet all o f the N uisance Tree List 
median tree planting standards in Section 4, parts 1E and 1F o f 
the Urban Fores try Manual if it were a newly planted tree. 
8. T he tree roots are causing damage to paved surfaces, 
infras tructure, utilities, buildings or other parts o f the built 
environment. 
9. The tree location conflicts with areas o f public street widening, 
construction or extension as shown in the T ransportation 
Sys tem Plan. 
10. Tree removal is reguired for the purposes o f an approved 
building or land use permit, utility or infrastructure installation 
or utility or infras tructure repair. 
11 . T he tree is recommended for removal by a de signa ted fire 
marshal for T ualatin Valley Fire and Rescue because it presents 
a significant fire risk to habitable structures or limits emergency 
access for rescue workers, and the risk or access issue canno t be 
abated through pruning or o ther means that results in tree 
retention. 
~-~-
----- -- ---
Sect i o n 5- M e di a n Tr ee Rem ova l S t a nd a rd s 
Ci t y o f T i ga rd U rb a n Fo r es tr y M a nu a l 
City of Tigard Urban Forestry Code Rc,·isio ns I Volume IV I 21 
Page 5-1 
N otes: 
Page 5-2 
12. The tree is part o f a stand o f trees, and a certified arborist or 
certified fores ter determines that thinning o f interior trees 
within the stand o f trees is necessary for overall stand health, 
the thinning will result in no less than 80 percent canopy 
cover at maturity for the area to be thinned, and that thinning 
o f non-native trees is maximized prio r to thinning o f native 
trees. 
C. U nless removed fo r thinning purposes (part 1.B.11 above) the city 
manager or designee shall condition the removal o f a median tree 
upon the planting o f a replacement tree within the same median as 
the tree was removed in accordance with the Median T ree Planting 
Standards in Section 4, part 1 o f the Urban Fores try Manual. T he city 
manager or designee may consider existing trees as replacement trees 
if they meet all applicable species, size, condition and location 
requirements in Section 4, part 1 and were no t already required to be 
planted or preserved by the Tigard Municipal Code. 
D . If the Median T ree Planting Standards in Section 4, part 1 o f the 
U rban Fores try Manual preclude replanting within the same median 
as the tree was removed, the applicant shall be exempt from planting 
a replacement tree. 
END DF SECTION 
Sec ti o n 5- Me di a n T r ee R e m ova l S t a n dar d s 
C it y o f T i ga rd U rb an Fo r es t ry M a nu a l 
Ciry of Tigard Urban l:orc>try C:odc Rc,·i>iom I \'olumc I\ ' I 22 
Section 6- Sensitive Lands Tree Removal and Replacement Standards 
Part 1. Sensitive Lands Tree Removal Standards: 
A . Native trees in sensitive lands shall be removed in a manner consistent 
with tree care industry standards. 
B. T he city manager or designee shall approve the removal o f a native 
tree in sensitive lands if any one o f the following criteria are met: 
1. The tree is a " hazard tree" as defined in Chapter 8.02 and 
" hazard tree abatement" as defined in Chapter 8.02 cannot be 
completed in a manner that results in tree retention consistent 
with tree care industry standards. 
2. The tree is dead. 
3. The tree is in an advanced state o f decline with insufficient live 
foliage, branches, roots or other tissue to sustain life. 
4. The tree is infes ted with pes ts or diseases that if left untrea ted 
will cause the tree to die, enter an advanced state o f decline, or 
cause other trees to die or enter an advanced state of decline. 
5. The tree has sustained physical damage that will cause the tree 
to die or enter an advanced state o f decline. If the physical 
damage was caused by a person in violation o f Chapter 8.10 o f 
the Tigard Municipal Code, the enforcement process outlined 
in Section 8.02.030 shall be completed prior to approval. 
6. T he tree roots are causing damage to paved surfaces, 
infras tructure, utilities, buildings or o ther parts o f the built 
environment. 
7. T he tree location conflicts with areas o f public street widening, 
construction or extension as shown in the T ransportation 
Sys tem Plan. 
8. Tree removal is required for the purposes o f an approved 
building or land use permit, utility or infrastructure installation 
or utili ty or infras tructure repair. 
9. The tree is recommended for removal by a designated fire 
marshal for Tualatin Valley Fire and Rescue because it presents 
a significant fire risk to habitable structures or limits emergency 
access for rescue workers, and the risk or access issue cannot be 
abated through pruning or other means that results in tree 
retention. 
10. A certified arborist or certified forester determines that 
thinning o f interior trees within a stand o f trees is necessary for 
overall stand health, the thinning will result in no less than 80 
percent canopy cover at maturity for the area to be thinned, 
and that thinning o f non-native trees is maximized prior to 
thinning o f native trees. 
Sec ti o n 6 - Se n si ti ve L a nd s Tr ee R e m ova l a nd 
R e pla ce m e nt S tand a rd s 
C it y o f T i ga rd U rb a n Fo r es tr y M a nual 
City o f Tigard Urban Forestry Code Re,·isions I Volume IV I 23 
N otes: 
Page 6-1 
-
Norc~: 
See . \ ppcndix 5 for 
Narivc Tn:c Li~r 
Page 6-2 
c. 
D . 
U nless removed for thinning purposes (part 1.B.10 above) the city 
manager o r designee shall condition the removal of each tree in 
sensitive lands upon the planting o f a replacement tree in accordance 
with the Sensitive Lands Tree Replacement Sta ndards in Section 6, 
part 2 of the U rban Forestry Manual. 
I f the Sensitive Lands Tree Replacement Standards in Section 6, part 2 
preclude replanting within the same property as the tree that was 
removed, the applicant shall be exempt from planting a replacement 
tree. 
P art 2. Sensitive Lands Tree Replacement Standards: 
A. 
B. 
c. 
D. 
E. 
Replacement trees shall be planted in a manner consistent with tree 
care industry standards. 
The minimum size of a replacement tree shall be 2 fee t in height (from 
the top of the root ball) or equivalent to a 1 gallon container size. 
Replacement trees shall be selected from the native tree list in the 
Urban Forestry Manual. 
The city manager or designee may consider native trees that are less 
than 6 inches DBH as replacement trees if they meet all applicable 
species, size, condition and loca tion requirements in this section and 
were no t already required to be planted by the Tigard Municipal Code. 
T he location of replacement trees shall be as follows: 
1. As close as practicable to the location of the tree that was 
removed provided the loca tion complies with the o ther 
standards in this section; 
2. No closer than 10 feet on center from newly planted or 
ex1sung trees; 
3. Trees categorized as small stature on the native tree list in the 
U rban Forestry Manual o r by the city manager or designee 
shall be spaced no closer than 15 feet from the face of 
habitable buildings; 
4. T rees categorized as medium stature on the native tree list in 
the U rban Forestry Manual or by the city manager or 
designee shall be spaced no closer than 20 feet from the face 
of habitable buildings; 
5. Trees categorized as large stature on the native tree list in the 
Urban Fores try Manual or by the city manager or designee 
shall be spaced no closer than 30 feet from the face of 
habitable buildings; 
6. T rees categorized as small sta ture on the native tree list in the 
Urban Forestry Manual or by the city manager or designee 
shall no t be planted with the center of their trunks closer than 
2 feet from any hard surface paving; 
Sec ti o n 6- Sensitive L an d s Tree R e mo va l and 
R e pla ce ment Standards 
City o f Tigard U rb a n Forestry Manual 
City o f T igard Urban h >rl':-' try Cotk RtTi:.; io ns I Voluml' I\' I 24 
F. 
7. 
8. 
Trees categorized as medium stature on the native tree list in 
the Urban Forestry Manual shall not be planted with the center 
o f their trunks closer than 2 1/2 feet from any hard surface 
paving; Trees categorized as large stature on the native tree list 
in the Urban Fores try Manual or by the city manager or 
designee shall not be planted with the center o f their trunks 
closer than 3 feet from any hard surface paving; and 
\\!here there are overhead utili ty lines, the tree species selected 
shall be o f a type which, at full maturity, will not interfere with 
the lines. 
T he city manager or designee may allow for an "in lieu o f planting fee" 
equivalent to the city's cos t to plant a tree in sensitive lands per the 
standards in this Section and maintain a tree in sensitive lands per the 
standards in Section 8.10.030 o f the Tigard Municipal Code for a 
period o f three years after planting. Payment o f an in lieu o f planting 
fee shall sa tisfy the sensitive lands tree replacement requirement. 
END OF SECnDN 
Sec t io n 6- Se n s i tive L a nd s T r ee R e m ova l a nd 
R e pl ace m e nt S t a nd ar d s 
C it y o f Tiga rd U r ba n Fo r es tr y M a nu a l 
Ciry of Tigard Urban l'orcslry Code Revisions I Volume 1\' I 25 
Notes: 
Sec ivlastcr l1ces and 
Charges Schedule for 
curren t fees 
Page 6-3 

Part 1. 
A. 
B. 
Section 7 - D evelopmen t Tree Rem oval and Replacem ent Standards 
D evelopment Tree Rem oval Standards: 
Trees subj ect to the requirements o f Chapter 8.12 shall be removed in 
a manner consistent with tree care industry standards. 
T he city manager or designee shall approve the removal of trees 
subject to the requirements o f Chapter 8.12 if any one of the 
following criteria are met: 
1. T he tree is a " hazard tree" as defined in Chapter 8.02 and 
" hazard tree abatement" as defined in Chapter 8.02 cannot be 
completed in a manner that results in tree retention consistent 
with tree care industry standards. 
2. T he tree is dead. 
3. T he tree is in an advanced state o f decline with insufficient live 
4. 
5. 
6. 
7. 
foliage, branches, roots or other tissue to sustain life. 
T he tree is infes ted with pes ts or diseases that if left untreated 
will cause the tree to die, enter an advanced state o f decline or 
cause o ther trees to die or enter an advanced state of decline. 
T he tree has sustained physical damage that will cause the tree 
to die or enter an advanced state o f decline. If the physical 
damage was caused by a person in violation o f Chapter 8.12 of 
the Tigard Municipal Code, the enforcement process outlined 
in Section 8.02.030 shall be completed prior to approval. 
T he tree is listed in the nuisance tree list. 
T he tree roots are causing damage to paved surfaces, 
infras tructure, utilities, buildings or o ther parts o f the built 
environment. 
8. T he tree location conflicts with areas o f public street widening, 
construction or extension as shown in the Transportation 
Sys tem Plan. 
9. T ree removal is required for the purposes o f an approved 
building or land use permit, utili ty or infrastructure installation, 
or utility or infras tructure repair. 
10. T he tree is recommended for removal by a designated fire 
marshal for Tualatin Valley Fire and Rescue because it presents 
a significant fire risk to habitable structures or limits emergency 
access for rescue workers, and the risk or access issue cannot be 
abated through pruning or other means that results in tree 
retention. 
11 . T he tree is part of a stand o f trees, and a certified arborist or 
certi fied fores ter determines that thinning o f interior trees 
within the stand of trees is necessary for overall stand health, 
the thinning will result in no less than 80 percent canopy cover 
at maturi ty for the area to be thinned, and that thinning of non-
native trees is maximized prior to thinning o f native trees. 
Sec ti o n 7- De ve l o pm e nt Tree Rem ova l a nd 
R e pl ace m e nt Standards 
City o f Tigard U rb a n F o r est r y M a nu a l 
City o f Tigard Urban Forestry Code Revisions I Volume IV I 27 
Notes: 
Sec t\ ppcndix 6 for 
N uisance Tree I -ist 
Page 7-1 
Norcs: 
Sec , \ ppcndices 2-5 
fo r 1\ pprovcd Tree 
Lists 
Sec , \ ppcndix 5 for 
Na tive Tree List 
Page 7-2 
c. Unless removed fo r thinning purposes (Part 1.B.11 above) the city 
manager or designee shall condition the removal o f each tree upon the 
planting of a replacement tree in accordance with the D evelopment 
T ree Replacem ent Standards in Section 7, part 2 o f the Urban Fores try 
Manual. 
D . If the D evelopment Tree Replacement Standards in Section 7, part 2 
preclude replanting within the same proper ty as the tree that was 
removed, the applican t shall be exempt from planting a replacem ent 
Part 2. 
A. 
B. 
c. 
D . 
tree. 
D evelopment Tree Replacem ent Standards: 
Replacement trees shall be planted in a manner consistent "vith tree 
care industry standards. 
T he replacement tree shall be loca ted so as to replace the function of 
the tree that was removed. For example, trees rem oved from parking 
lots shall be replaced in parking lo ts and trees rem oved from 
landscape buffers shall be replaced in landscape buffers. If planting in 
the same location would no t comply with the o ther standards in this 
section, the replacement tree shall be planted as close as practicable to 
the tree that was rem oved in compliance with the o ther standards in 
this section. 
T he replacement species shall be the same stature or greater (at 
maturity) as the tree that was removed. If planting the same sta ture or 
grea ter tree would no t comply with the o ther standards in this section, 
the replacement tree shall be the most similar stature practicable as the 
tree that was removed in compliance with the o ther standards in this 
secuon. 
If the tree that was removed was part of a stand o f trees, then the 
following standards apply to the replacement tree: 
1. T he replacement tree shall be selected from the native tree list 
in the U rban Fores try Manual unless otherwise approved by the 
city manager or designee; 
2. The minimum size of the replacement tree shall be 2 feet in 
height (from the top o f the root ball) or equivalent to a 1 gallon 
container size; and 
3. T he replacement tree shall be loca ted as follows: 
a. No closer than 10 fee t on center from newly planted or 
existing trees; 
b. T rees ca tegorized as sm all stature on the native tree list 
in the U rban Fores try Manual or by the city manager or 
designee shall be spaced no closer than 15 feet from the 
face o f habitable buildings; 
c. T rees ca tegorized as medium sta ture on the native tree 
list in the U rban Fores try Manual o r by the city 
manager or designee shall be spaced no closer than 20 
feet from the face o f habitable buildings; 
Sectio n 7 - D eve l op m en t Tree R emoval ao d 
R ep l aceme n t S t a n da r ds 
C i ty o f Tiga r d U rb an Forest r y Ma nu a l 
City of Tigard Urban l'orc>t ry Code Rc1·isions I \'olumc /\ ' I 2R 
E. 
d. T rees categorized as large stature on the native tree 
list in the Urban Fores try Manual or by the city 
manager or designee shall be spaced no closer than 
30 feet from the face o f habitable buildings; 
e. T rees categorized as small stature on the native tree 
list in the Urban Fores try Manual or by the ci ty 
manager or designee shall no t be planted with the 
center o f their trunks closer than 2 feet from any 
hard surface paving; 
f. T rees categorized as medium stature on the native 
tree list in the Urban Fores try Manual shall no t be 
planted with the center o f their trunks closer than 2 
V2 feet from any hard surface paving; 
g. T rees categorized as large stature on the native tree 
list in the Urban Fores try Manual or by the city 
manager or designee shall no t be planted with the 
center o f their trunks closer than 3 feet from any 
hard surface paving; and 
h. \X!here there are overhead utili ty lines, the tree 
species selected shall be o f a type which, at full 
maturity, will not interfere with the lines . 
If the tree that was removed was an open grown tree, then the 
following standards apply to the replacement tree: 
1. The replacement tree shall be selected from any o f the tree lists 
in the Urban Forestry Manual (except the nuisance tree list) 
unless o therwise approved by the city manager or designee; 
2. The minimum size o f the replacement tree shall be 11/ 2 inch 
caliper for deciduous or 6 fee t in height for evergreen; and 
3. The replacement tree shall be located as follows: 
a. T rees categorized as small stature on any o f the tree lists 
in the Urban Fores try Manual or by the city manager or 
designee shall be spaced no closer than 15 feet o n 
center from other newly planted or existing trees and 10 
feet from the face o f habitable buildings; 
b. Trees categorized as medium stature on any o f the tree 
lists in the Urban Fores try Manual or by the city 
manager or designee shall be spaced no closer than 20 
feet on center from other newly planted or exis ting 
trees and 15 feet from the face o f habitable buildings; 
c. T rees categorized as large stature on any of the tree lists 
in the Urban Fores try Manual or by the city manager or 
designee shall be spaced no closer than 30 feet on 
center from other newly planted or existing trees and 20 
feet from the face o f habitable buildings; 
Sec ti o n 7- D eve l o pm e nt T r ee R e m ova l a nd 
R ep l ace m e nt S t a nd a rd s 
Ci t y o f Tiga rd U rb a n F o r es tr y M a nu a l 
City o f Tigard Urban Forestry Code Rc\'isions I Vo lume IV I 29 
Notes: 
Sec J\ ppendices 2-5 
for i\ pproved 'free 
Lists 
Sec Appendix 6 fo r 
N uisance 'free List 
Page 7-3 
N ote>: 
See Il l aster h .:es and 
Charges Schedule for 
current fees 
Page 7-4 
F. 
G. 
d. 
e. 
f. 
g. 
h. 
Trees determined by the city manager or designee to 
have a mature spread o f less than 20 feet shall be 
considered small stature, and shall be spaced no closer 
than 15 feet on center from o ther newly planted or 
existing trees and 10 fee t from the face o f habitable 
buildings; 
T rees categorized as small stature on any of the tree 
lists in the U rban Forestry Manual or by the city 
manager or designee shall not be planted with the 
center of their trunks closer than 2 fee t from any hard 
surface paving; 
Trees categorized as medium stature on any of the 
tree lists in the Urban Forestry Manual shall not be 
planted with the center of their trunks closer than 2 
1/2 feet from any hard surface paving; 
Trees categorized as large stature on any of the tree 
lists in the U rban Forestry Manual or by the city 
manager or designee shall not be planted with the 
center o f their trunks closer than 3 feet from any hard 
surface paving; and 
\X!here there are overhead utili ty lines, the tree species 
selected shall be o f a type which, at full maturity, will 
no t interfere with the lines. 
The city manager or designee may consider existing trees as 
replacement trees if they meet all applicable species, size, condition 
and location requirements in this Section and were not already 
required to be planted or preserved by the Tigard Municipal Code. 
The city manager o r designee may allow for an "in lieu o f planting 
fee" equivalent to the city's cost to plant a tree per the standards in 
this Section and maintain a tree per the standards in section 8.12.030 
of the Tigard Municipal Code for a period o f three years after 
planting. Payment of an in lieu of planting fee shall satisfy the 
development tree replacement requirement. 
• 
·-
END OF SECTION 
Sec t io n 7 - D eve l o pm e nt T r ee R e m ova l an d 
R e pl ace m e n t Sta nd a rd s 
C it y o f T i ga rd U rb a n Fo r estry M an u a l 
City of T igard Urban Forestry Code Rc,·isions I \ 'olumc I\ ' I .10 
Section 8 - U rban Forestry Fund T ree Rem oval and Replacem ent Standards 
P art 1. U rban Forestry Fund Tree Rem oval Standards: 
A. Trees subject to the requirements o f Chapter 8.14 shall be removed in a 
manner consistent with tree care industry standards. 
B. The city manager or designee shall approve the removal o f trees subject 
to the requirements o f Chapter 8.14 if any one o f the following criteria 
are met: 
1. The tree is a " hazard tree" as defined in Chapter 8.02 and 
" hazard tree abatement" as defined in Chapter 8.02 canno t be 
completed in a manner that results in tree retention consistent 
wi th tree care industry standards. 
2. The tree is dead. 
3. T he tree is in an advanced state o f decline with insufficient live 
foliage, branches, roots or o ther tissue to sustain life. 
4. The tree is infested with pes ts or diseases that if left untrea ted 
will cause the tree to die, enter an advanced state of decline or 
cause other trees to die or enter an advanced state of decline. 
5. The tree has sustained physical damage that will cause the tree 
to die or enter an advanced state o f decline. If the physical 
damage was caused by a person in violation o f Chapter 8.14 o f 
the Tigard Municipal Code, the enforcement process outlined 
in Section 8.02.030 shall be completed prior to approval. 
Notes: 
6. The tree is listed in the nuisance tree list. I Sec Appendix 6 for 
7. The tree roo ts are causing damage to paved surfaces, N uisance Tree List 
infras tructure, utilities, buildings or other parts o f the built 
--
environment. 
8. The tree location conflicts with areas o f public street widening, 
construction or extensio n as shown in the Transportation 
Sys tem Plan. 
9. Tree removal is required for the purposes o f an approved 
building or land use permit, utili ty or infras tructure installation 
or utility or infrastructure repair. 
10. The tree is recommended for removal by a designated fire 
marshal for T ualatin Valley Fire and Rescue because it presents 
a significant fire risk to habitable structures or limits emergency 
access for rescue workers, and the risk or access issue canno t be 
abated through pruning or o ther means that results in tree 
retention. 
11. T he tree is part o f a stand o f trees, and a certified arborist or 
certified fores ter determines that thinning o f interior trees 
within the stand o f trees is necessary for overall stand health, 
the thinning will result in no less than 80 percent canopy cover 
at maturi ty for the area to be thinned, and that thinning o f non-
native trees is maximized prior to thinning o f native trees. 
Sec ti o n 8- U rb a n Fo r es tr y Fund T r ee R e m ova l a nd 
R e pl ace m e nt S t a nd a rd s 
Cit y o f Tiga rd U rb a n Fo r es tr y Ma nu a l 
-
City o f Tigard Urban Forestry Code Rc,·isio ns I Volume I\' I 31 
Page 8-1 
-- - -
Note>: 
Sec :\ppcndiccs 2-5 
for , \ pproved Tree 
Lists 
Sec , \ ppen dix 5 for 
the Native Tree Li st 
Page 8-2 
c. 
D . 
P art 2. 
A. 
B. 
c. 
U nless removed for thinning purposes (part 1.B.11 above) the city 
manager or designee shall condition the removal of each tree upon the 
planting of a replacement tree in accordance with the Urban Forestry 
Fund Tree Replacement Standards in Section 8, part 2 o f the U rban 
Forestry Manual. 
If the U rban Forestry Fund Tree Replacement Standards in Section 8, 
part 2 preclude replanting within the same property as the tree that 
was removed, the applicant shall be exempt from planting a 
replacement tree. 
U rban F o restry Fund Tree Replacement Standards: 
Replacement trees shall be planted in a manner consistent with tree 
care industry standards. 
T he replacement species shall be the same stature o r greater (at 
maturity) as the tree that was removed . If planting the same stature or 
greater tree would not comply with the other standards in this sec tion, 
the replacement tree shall be the most similar stature practicable as the 
tree that was removed in compliance with the o ther standards in this 
section . 
If the tree that was removed was part of a stand o f trees, then the 
following standards apply to the replacement tree: 
1. T he replacement tree shall be selected from the native tree list 
in the Urban Forestry Manual unless otherwise approved by the 
city manager or designee; 
2. The minimum size o f the replacement tree shall be 2 feet in 
height (from the top o f the root ball) or equivalent to a 1 gallon 
container size; and 
3. The replacement tree shall be located as follows: 
a. No closer than 10 feet on center from newly planted or 
existing trees; 
b. T rees categorized as small sta ture on the native tree list 
in the Urban Forestry Manual or by the city manager or 
designee shall be spaced no closer than 15 feet from the 
face of habitable buildings; 
c. Trees categorized as medium stature on the native tree 
list in the U rban Forestry Manual or by the city 
manager or designee shall be spaced no closer than 20 
feet from the face o f habitable buildings; 
d. Trees ca tegorized as large stature on the native tree list 
in the Urban Fores try Manual or by the city manager or 
designee shall be spaced no closer than 30 feet from the 
face of habitable buildings; 
e. Trees categorized as small stature on the native tree list 
in the U rban Forestry Manual o r by the city manager or 
designee shall not be planted with the center of their 
trunks closer than 2 feet from any hard surface paving; 
Sec t io n 8 - U rb a n F o r es tr y F und T r ee R e m ova l a nd 
R e pl ace m e nt S t a nd a rd s 
C it y o f T i ga rd U rb a n Fo r es tr y Manu a l 
City of Tigard Urban Forestry Code Rc,-isions I \'nlumc 1\' I .)2 
D. 
f. Trees categorized as medium stature on the native tree 1 Notes: 
list in the Urban Forestry Manual shall not be planted 
with the center of their trunks closer than 2 Vz feet 
from any hard surface paving; 
g. Trees categorized as large stature on the native tree list 
in the Urban Forestry Manual or by the city manager or 
designee shall not be planted with the center of their 
trunks closer than 3 feet from any hard surface paving; 
and 
h. \V'here there are overhead utility lines, the tree species 
selected shall be of a type which, at full maturi ty, will 
not interfere with the lines . 
If the tree that was removed was an open grown tree, then the 
following standards apply to the replacement tree: 
1. T he replacement tree shall be selected from any o f the tree lists 
in the Urban Forestry Manual (except the nuisance tree list) 
unless otherwise approved by the city manager or designee; 
2. The minimum size of the replacement tree shall be 1 1/z inch 
caliper for deciduous or 6 feet in height for evergreen; and 
3. The replacement tree shall be located as follows: 
a. Trees categorized as small stature on any of the tree lists 
in the Urban Forestry Manual or by the city manager or 
designee shall be spaced no closer than 15 feet on 
center from other newly planted or exis ting trees and 10 
feet from the face of habitable buildings; 
b. Trees categorized as medium stature on any of the tree 
lists in the Urban Fores try Manual or by the city 
manager or designee shall be spaced no closer than 20 
feet on center from o ther newly planted or exis ting 
trees and 15 feet from the face of habitable buildings; 
c. Trees categorized as large sta ture on any of the tree lists 
in the Urban Forestry Manual or by the city manager or 
designee shall be spaced no closer than 30 feet on 
center from other newly planted or existing trees and 20 
feet from the face of habitable buildings; 
d. T rees determined by the city manager or designee to 
have a mature spread of less than 20 feet shall be 
considered small stature, and shall be spaced no closer 
than 15 feet on center from o ther newly planted or 
existing trees and 10 feet from the face of habitable 
buildings; 
e. Trees categorized as small stature on any o f the tree lists 
in the Urban Forestry Manual or by the city manager or 
designee shall not be planted with the center of their 
trunks closer than 2 feet from any hard surface paving; 
Sec t io n 8 - U rb a n Fo r es tr y F und Tree R e m ova l a nd 
R e pl ace m e nt S t a nd a rd s 
City o f T i ga rd U r ba n Fores t ry M a nu a l 
City of Tigard Urban Forestry Code Rc\'isions I Volume IV I 33 
Sec Appendices 2-5 
for i\ pprovcd Tree 
I .isrs 
Sec ~i\ ppendix 6 for 
N uisance Tree I .ist 
Page 8-3 
!'\orcs: 
Sec l\ I as ter I <'ces and 
Charges Schedule 
for current fee 
Page 8-4 
E. 
F. 
f. 
g. 
h. 
T rees categorized as medium sta ture on any of the 
tree lists in the Urban Forestry Manual shall not be 
planted with the center o f their trunks closer than 2 
1/2 feet from any hard surface paving; 
Trees categorized as large stature on any of the tree 
lists in the Urban Forestry Manual or by the city 
manager o r designee shall not be planted with the 
center of their trunks closer than 3 feet from any hard 
surface paving; and 
\\!here there are overhead utility lines, the tree species 
selected shall be of a type which, at full maturity, will 
no t interfere with the lines. 
T he city manager o r designee may consider existing trees as 
replacement trees if they meet all applicable species, size, condition 
and location requirements in this section and were no t already 
required to be planted or preserved by the Tigard Municipal Code. 
T he city manager or designee may allow for an "in lieu of planting 
fee" equivalent to the city's cost to plant a tree per the standards in 
this section and maintain a tree per the standards in section 8.14.030 
of the Tigard Municipal Code for a period o f three years after 
planting. Payment o f an in lieu of planting fee shall sa tisfy the urban 
forestry fund tree replacement requirement. 
END OF SECTION 
Sec ti o n 8 - U r ba n Fo r es tr y F und T r ee R e m ova l a nd 
R e pl ace m e nt S t a nd a rd s 
C i ty of T i ga rd U rb a n Fo r est r y Ma nu a l 
City of Tigard Urban l'orcstry Code Rc,·isions I \'olumc /\ ' I 34 
Section 9- H eritage Tree D esign ation Rem oval Standards 
Part 1. 
A. 
B. 
H eritage Tree D esignation Rem oval Standards: 
H eritage trees subject to the requirements of Chapter 8.16 shall be 
removed in a manner consistent with tree care industry standards. 
The city manager or designee shall approve the removal o f heritage 
tree designation if any one o f the following criteria are met for a 
designated heritage tree: 
1. T he heritage tree is a " hazard tree" as defined in Chapter 8.02 
and " hazard tree abatement" as defined in Chapter 8.02 cannot 
be completed in a manner that results in tree retention 
consistent with tree care industry standards. 
2. T he heritage tree is dead. 
3. T he heritage tree is in an advanced state o f decline wi th 
insufficient live foliage, branches, roots or other tissue to 
sustain life. 
4. T he heri tage tree has sustained physical damage that will cause 
the tree to die or enter an advanced state o f decline. If the 
physical damage was caused by a person in violation o f Chapter 
8.16 of the Tigard Municipal Code, the enforcement process 
outlined in Section 8.02.030 shall be completed prior to 
approval. 
5. T he tree is recommended for removal by a designated fire 
marshal for T ualatin Valley Fire and Rescue because it presents 
a significan t fire risk to habitable structures or limits emergency 
access for rescue workers, and the risk or access issue canno t be 
abated through pruning or other means that results in tree 
retention. 
6. T he heritage tree is part o f a stand o f heritage trees, and a 
certi fied arborist or certified fores ter determines that thinning 
o f interior heritage trees within the stand o f heritage trees is 
necessary for overall stand health, the thinning will result in no 
less than 80 percent canopy cover at maturi ty for the area to be 
thinned, and that thinning o f non-native heritage trees is 
maximized prior to thinning o f native heritage trees. 
C. Replacement o f heritage trees is not required unless a heritage tree is 
also subject to o ther provisio ns o f the Tigard Municipal Code that 
require replacement. 
END OF SECTION 
Sec ti o n 9 - H er i tage T r ee D esig n a t io n R e m ova l Sta nd a rd s 
C it y o f T i ga rd U rb a n Fo r es tr y M a nu a l 
Cit}' o f Tigard Urban Forestry Code Rc,·isio ns I \'olumc IV I 35 
N otes: 
Page 9-1 
•J. 
:~ 
-Section 10- Urban F orestry Plan Standards 
P art 1. U rban Forestry Plan- Tree Preservation and Removal Site Plan 
Requirements: 
A. The plan shall be standard size D (24" x 36"), a reduced legal size and 
a PDF, and include all items in part 1.B-O below. When required for 
clarity, the development impact area information in part 1.I may be 
detailed separately on multiple plan sheets provided that all of the 
B. 
c. 
D. 
remaining items in part 1 are included for reference. 
Date of drawing or last revision. 
North arrow. 
Bar scale as follows: 
1. Less than 1.0 acres: 
2. 1.0 - 5.0 acres: 
3. 5.0- 20.0 acres: 
4. Over 20.0 acres: 
1" = 10' 
1" = 20' 
1" =50' 
1" = 100'. 
E. Site address or assessor's parcel number. 
F. The location of existing and proposed property lines. 
G. Location of existing and proposed topographic lines at 1-foot 
contours unless otherwise approved. 
H . The location and type of sensitive lands areas. 
I. Proposed activities within the development impact area, including but 
not limited to: 
1. Construction of structures and walls; 
2. Paving and graveling; 
3. Utility and irrigation installation; 
4. Construction parking and construction equipment storage; 
5. Landscaping; 
6. Grading and filling; 
7. Stockpiling; 
8. Demolition and tree removal; 
9. Trenching and boring; and 
10. Any other activities that require excavation or soil disturbance. 
J. The trunk locations, driplines, assigned numbers and "X" marks when 
applicable (indicating trees proposed for removal) for the following 
trees within the development impact area and within 25 feet of the 
development impact area: 
1. Trees greater than or equal to 6 inch DBH; and 
2. Other trees that require a permit to remove by Title 8 and are 
less than 6 inch DBH. 
K. The trunk locations, driplines and assigned numbers for the following 
trees that are not within the development impact area: 
1. Open grown trees greater than or equal to 6 inch DBH; and 
Sec ti o n 1 0 - U rb a n F o r es tr y Pl a n S tand a rd s 
C it y o f T i ga rd U rb a n F o r es tr y M a nu a l 
- - --
Ciry of'figard Urban Forestry Code Re,·isions I \'olumc IV I 37 
Notes: 
Sec i\ ppendix 7 for 
I •:xamplc Tree 
Preservation and 
Removal Site Plan 
Page 10-1 
--- ~ -~" --~-
N otes: 
Sec 1\ ppcmlix 8 for 
I •:xample T ree 
Canopy Site !'Ian 
P age 10-2 
2. O ther trees that require a permit to remove by Tide 8 and are 
less than 6 inch DBI-I. 
L. T he driplines o f stand grown trees greater than o r equal to 6 inch 
DBH that form a contiguous tree canopy. T he driplines may be 
delinea ted at the outer edge o f the stand. Each stand shall be assigned 
a number. 
M. T he location and type o f proposed tree protection fencing. If the 
loca tion o f the tree protection fencing will be phased, indicate the 
location o f the tree protection fencing for each corresponding phase. 
T ree protection fencing shall be minimum 5-foot tall metal unless 
o therwise approved by the city manager o r designee. 
N. Any supplemental tree preserva tion specifications consistent with tree 
care industry standards that the project arborist or landscape architect 
has determined are necessary for the continued viability of trees 
identified for preservation . 
0. A signature o f approval and statement from the proj ect arborist or 
landscape architect, attesting that the tree preservation and removal 
site plan meets all o f the requirem ents in Section 10, part 1 o f the 
Urban Fores try Manual. 
P art 2. 
A. 
B. 
c. 
U rban F orestry Plan- Tree Canopy Site Plan Requirements: 
The plan shall be standard size D (24" x 36"), a reduced legal size and 
PDF format, and include all item s in part 2.B-O below. 
Date o f drawing or last revision. 
North arrow. 
D . Bar scale as follows: 
1. 
2. 
3. 
4. 
less than 1.0 acres: 
1.0 - 5.0 acres: 
5.0 - 20.0 acres: 
Over 20.0 acres: 
1" = 10' 
1" = 20' 
1" = 50' 
1 II = 100'. 
E. Site address or assessor's parcel number. 
F. T he location o f proposed property lines. 
G. The loca tion o f proposed building footprints, utilities and irriga tion, 
streets and o ther paved areas. 
H . T he trunk locatio ns, driplines and assigned numbers for trees to be 
preserved in parts l.J and 1.K . Each tree o n bo th the tree 
preserva tion and rem oval site plan and tree canopy site plan shall be 
assigned the same number on bo th plans. 
I. The dripline locations o f stand grown trees proposed for preserva tion 
greater than or equal to 6 inch DBH that form a contiguous tree 
canopy. The dripline may be delinea ted at the outer edge o f the stand. 
E ach stand shall be assigned a number. Each stand on bo th the tree 
preserva tion and removal site plan and tree canopy site plan shall be 
assigned the same number on bo th plans. 
J. T he locatio n o f existing o r po tential areas o f tree growth limiting soils 
due to compac tion, drainage, fertility, pH, contamination o r o ther 
fac tors. 
Sectio n 1 0 - U r ba n Fo r es tr y Pl an S t a nd ar d s 
Cit y o f T i ga rd U rb a n Fo r es t r y M a nu a l 
City o f Tigard Urban l;nrcstry Code Rc,·isions I \ 'olumc 1\ ' I 3H 
K. 
L. 
Methods for improving areas o f tree growth limiting soils if tree 
planting is proposed in those locations. 
The location, species, caliper (in inches for deciduous) or height (in feet 
for evergreen), assigned numbers and depiction o f the mature tree 
canopy (in feet as identified on any o f the tree lists in the Urban 
Fores try Manual or by the city manager or designee) for all trees to be 
planted and maintained as open grown trees. The minimum size for all 
trees planted and maintained as open grown trees is 1 1/ 2 inch caliper 
for deciduous or 6 feet in height for evergreen. Open grown trees shall 
be selected from any of the tree lists in the Urban Fores try Manual 
(except the nuisance tree list) unless o therwise approved by the city 
manager or designee. If an open grown tree approved for planting is 
no t identified on any of the tree lists in the Urban Fores try Manual, 
then the project arborist or landscape architect shall determine the 
average mature tree canopy spread using available scientific literature 
for review and approval by the city manager or designee. The city 
manager or designee may consider trees less than 6 inch DBH as 
equivalent to newly planted trees if they meet all applicable species, 
size, condition and location requirements in this section. O verall, the 
selection o f open grown trees shall result in a reasonable amount o f 
diversity for the site. O pen grown trees shall be located as follows: 
1. T rees categorized as small stature on any o f the tree lists in the 
Urban Forestry Manual or by the city manager or designee shall 
be spaced no closer than 15 feet on center from other newly 
planted or existing trees and 10 feet from the face o f habitable 
buildings. In downtown Tigard (Mixed Use-Central Business 
District, MU-CBD), the setback from the face o f habitable 
buildings may be reduced if approved by the city manager or 
designee; 
2. Trees categorized as medium stature on any o f the tree lists in 
the Urban Forestry Manual or by the city manager or designee 
shall be spaced no closer than 20 feet on center from o ther 
newly planted or existing trees and 15 feet from the face o f 
habitable buildings. In downtown Tigard (Mixed Use-Central 
Business District, MU-CBD), the setback from the face of 
habitable buildings may be reduced if approved by the city 
manager or designee ; 
3. Trees categorized as large stature on any of the tree lists in the 
Urban Fores try Manual or by the city manager or designee shall 
be spaced no closer than 30 feet on center from other newly 
planted or existing trees and 20 feet from the face o f habitable 
buildings. In downtown Tigard (Mixed Use-Central Business 
Distric t, MU-CBD), the setback from the face o f habitable 
buildings may be reduced if approved by the city manager or 
designee; 
Notes: 
Sec 1\ ppcndiccs 2-5 
for 1\ pprovcd Tree 
I .ists 
Sec 1\ ppcndix 6 for 
N uisance Tree List 
------ ~-
s e c t i o n I 0 - U r b a n F o r e s t r y P I a n S t a n d a r d s Page 10-3 
C it y of T i ga rd U rb a n Fo r e s tr y M a nu a l 
- - - - - -- -
Ciry of Tigard Urban Fo restry Code Revisions I Volume IV I 39 
N ote" 
Sec ,\ ppcndix 5 
for Nati ve T ree 
J ,i sr 
Page 10-4 
M. 
4. 
5. 
6. 
7. 
8. 
T rees determined by the city manager or designee to have a 
mature spread o f less than 20 feet shall be considered small 
stature, and shall be spaced no closer than 15 feet on center 
from o ther newly planted or existing trees and 10 fee t from 
the face o f habitable buildings. In downtown Tigard (Mixed 
Use-Central Business District, MU-CBD), the setback from 
the face o f habitable buildings may be reduced if approved by 
the city manager or designee; 
Trees categorized as small stature on any o f the tree lists in 
the U rban Fores try Manual o r by the city manager or 
designee shall no t be planted with the center o f their trunks 
closer than 2 feet from any hard surface paving; 
T rees categorized as medium stature on any o f the tree lists in 
the Urban Fores try Manual shall no t be planted with the 
center o f their trunks closer than 2 % fee t from any hard 
surface paving; 
Trees categorized as large stature on any o f the tree lists in 
the Urban Forestry Manual or by the city manager or 
designee shall no t be planted with the center o f their trunks 
closer than 3 feet from any hard surface paving; 
Where there are overhead utility lines, the tree species 
selected shall be o f a type which, at full maturity, will no t 
interfere with the lines; and 
9. \X!here there is existing mature tree canopy or o ther areas 
with significant shade, the species selected shall be an 
understo ry tree according to available scientific literature. 
However, understory trees shall only be planted when the 
planting o f non-understory trees is precluded due to site 
constraints. 
The location, species, size (in height or container size), assigned 
number and depiction o f the mature tree canopy dripline as identified 
in the native tree list in the Urban Fores try Manual (delineated at the 
outer edge o f the stand) for all trees to be planted and maintained as 
stand grown trees . T he species o f trees planted and maintained as 
stand grown trees shall be selected from the native tree list in the 
Urban Forestry Manual. The depiction o f the mature tree canopy 
dripline shall be consis tent with dimensions in the native tree list. The 
minimum size o f stand grown trees shall be 2 feet in height (from the 
top o f the root ball) or equivalent to a 1 gallon container size. T he city 
manager or designee may consider trees less than 6 inch DBH as 
equivalent to newly planted trees if they meet all applicable species, 
size, condition and location requirements in this section . O verall, the 
selection o f stand grown trees shall result in a reasonable amount o f 
diversity for the site. Stand grown trees shall be located as follows: 
1. No closer than an average o f 10 fee t on center from newly 
planted o r existing trees; 
2. No further than an average o f 20 fee t on center from newly 
planted o r existing trees; 
Sec ti o n 10- U rb a n Fo r es tr y Pl a n Sta nd a rd s 
C it y o f T i ga rd Ur b a n Fo r est r y M a nu a l 
City of Tigard Urban l;orcst ry Code Rc,·isions I \'olumc 1\ ' I 40 
3. Trees categorized as small stature on the native tree list in the 1 N o tes: 
Urban Forestry Manual or by the city manager or designee shall 
be spaced no closer than 15 feet from the face of habitable 
buildings. In downtown Tigard (Mixed Use-Central Business 
District, MU-CBD), the setback from the face of habitable 
buildings may be reduced if approved by the city manager or 
designee; 
4. T rees categorized as medium stature on the native tree list in 
the Urban Fores try Manual or by the city manager or designee 
shall be spaced no closer than 20 feet from the face of habitable 
buildings. In downtown Tigard (Mixed Use-Central Business 
District, MU-CBD), the setback from the face of habitable 
buildings may be reduced if approved by the city manager or 
designee; 
5. T rees categorized as large stature on the native tree list in the 
Urban Fores try Manual or by the city manager or designee shall 
be spaced no closer than 30 feet from the face o f habitable 
buildings. In downtown Tigard (Mixed Use-Central Business 
District, MU-CBD), the setback from the face o f habitable 
buildings may be reduced if approved by the city manager or 
designee; 
6. Trees categorized as small stature on the native tree list in the 
Urban Fores try Manual or by the city manager or designee shall 
no t be planted with the center of their trunks closer than 2 feet 
from any hard surface paving; 
7. T rees categorized as medium stature on the native tree list in 
the Urban Fores try Manual shall not be planted with the center 
o f their trunks closer than 2 1/z feet from any hard surface 
pavtng; 
8. Trees categorized as large stature on the native tree list in the 
Urban Fores try Manual or by the city manager or designee shall 
not be planted with the center of their trunks closer than 3 feet 
from any hard surface paving; 
9. \X!here there are overhead utility lines, the tree species selected 
shall be of a type which, at full maturity, will not interfere with 
the lines; and 
10. \Vhere there is existing mature tree canopy or other areas with 
significant shade, the species selected shall be an understory 
tree according to available scientific literature. H owever, 
understory trees shall only be planted when the planting of 
non-understory trees is precluded due to space constraints. 
N. Any supplemental specifica tions that the project arborist or landscape 
architect has determined are necessary for the viability of trees 
proposed for planting. 
0 . A signature o f approval and statement from the project arborist or 
landscape architect, attes ting that the tree canopy site plan meets all of 
the requirements in Section 10, part 2 of the Urban Forestry Manual. 
-- ~- - -- -
Sec t io n 1 0 - U rb a n Fo r es tr y Pl a n S t a nd a rd s 
City o f T i gar d U rb a n Fo r es tr y M a nu a l 
City of Tigard Urban Forestry Code Rc\'isions I Volume 1\' I 41 
Page 10-5 
N otes: 
See , \ ppendix 9 for 
l•:xamplc 
Supplemental Report 
Template 
Page 10-6 
Part 3. 
A. 
B. 
c. 
D. 
Urban Forestry Plan- Supplemental Report Requirements: 
The supplemental report shall be provided by the proj ect arborist or 
landscape architect in paper and PDF format, and include all items in 
part 3.B-P below. 
Date of the report. 
The name, address, telephone number, email address and ISA certified 
arborist number of the project arborist o r stamp and registration 
number of the project landscape architect. 
The following inventory data in table or other such organized format 
corresponding to each tree in parts 1.] and 1.K in the tree preservation 
and removal site plan: 
1. The assigned tree number; 
2. T he genus, species and common name; 
3. DBH (in inches); 
4. Average tree canopy area (in square feet), calculated as follows: 
a. Average tree canopy area = (average tree canopy 
spread/ 2)2 x rc; 
5. Open grown tree o r stand grown tree; 
6. Heritage tree? (Y or N); 
7. Numerical condition rating (0-3) as follows: 
• iil:li!I t !Ii-1[!!i!IIl-1t' tli:Lil'. 
-Condition Overall Tree Amount of History Pests Extent 
rating 
0 
1 
2 
3 
vigor 
Dead to 
severe 
decline 
Declining 
:\verage 
Good to 
excellent 
canopy deadwood of failure of decay 
density 
< 30% Large; major More Infested i\ Iajor; 
1 scaffold than one conks 
branches scaffold and 
cavmes 
30-60% Twig and Scaffold In fested One to a 
branch branches few 
die back conks; 
small 
cavities 
-
60-90% Small twigs Small Minor Present 
branches only at 
prurung 
wounds 
90- Little or none None Minor to Absent 
100% Insignificant to 
present 
only at 
prumng 
wounds 
Section 10- U rban Fore s tr y Plan Sta nd a rd s 
City of Tigard Ur b an Fore s tr y Manua l 
City of Tigard Urban l;orc< try Code l<c,·ision < I \ 'olumc 1\ ' I 42 
8. N umerical suitabili ty for preserva tion rating (0-3) as follows: 
l1lmiL ifiliP.lln 
0 The tree is a "hazard tree" as defined in Chapter 18.120 of the Tigard 
D evelopment Code and "hazard tree abatement" as defined in Chapter 18.120 
in the Tigard Development Code cannot be completed in a manner that results 
in tree retention consistent with tree care industry standards. 
~ -------The tree is dead, in severe decline 
or declining but may be retained if desirable for wildlife or other benefi ts 
because it is not considered a "hazard tree" or "hazard tree abatement" could 
be performed . 
1------......:;_ 
2 The tree has average health and/ or structural stability that could be alleviated 
3 
L.__ 
9. 
10. 
with treatment; the tree will be less resilient to development impacts and will 
require more frequent management and monitoring after development than a 
tree rated as a "3". 
The tree has good to excellent health and structural stability; the tree will be 
more resilient to development impacts, and will require less frequent 
management and monitoring after development than a tree rated as a "2" . 
Proposed for preservation? (Y or N); and 
Additional comments. 
~ 
E. T he following inventory data in table or o ther such organized format 
corresponding to each exis ting stand in the tree preservation and 
removal site plan: 
-- -
1. T he assigned stand number; 
2. The genus, species and common name o f the tree species 
es timated to be dominant in the stand; 
3. T he genus, species and common name of the tree species 
es timated to be the second and third most common in the 
stand; 
4. T he es timated average DBH (in inches) o f the dominant tree 
species in the stand; 
5. The es timated average DBH (in inches) of bo th the second and 
third most common tree species in the stand; 
6. T he es timated average condition rating (per part 3.D.7) of the 
dominant tree species in the stand; 
7. The es timated average condition rating (per part 3.D.7) of both 
the second and third most common tree species in the stand; 
8. The to tal on site tree canopy area (in sguare feet) of the stand; 
9. N umerical suitability for preservation rating of the stand (0-3) 
as follows: 
Sec ti o n 10- U rb a n F o r es tr y Pl a n S t a nd a rd s 
Cit y o f Ti ga rd U rb a n F o r es tr y M a nu a l 
- -
Ciry of Tigard Urban Forcsrry Code Rc,·isions I Volume IV I 43 
N orcs: 
Page 10-7 
- ·- ~ -
Note~: 
Page 10-8 
-.• I(ITi 
N uisance trees are the dominant species in the stand and / or continued viability o f 
the stand is unlikely due to pests, diseases, competition from nuisance tree or plant 
species, hydrologic changes or other fac tors. 
1 The stand requires a curren tly cost prohibitive level of investm ent and management 
o f pests, diseases, nuisance tree or plant species, hydrology or other factors to 
become viable. 
2 The stand is viable bur requires more frequent management and monitoring of pests, 
diseases, nuisance tree or plant species, hydrology or other fac tors for continued 
viabili ty than a stand rated as a "3" . 
3 The stand is viable and requires less frequent management and monitoring of pests, 
diseases, nuisance tree or plant species, hydrology or other facto rs for continued 
viabili ty than a stand rated as a "2" . 
10. T he to tal on site tree canopy area (in square feet) of the stand 
proposed fo r preserva tio n; and 
11 . Additional comments. 
F. Supplemental specifica tions regarding the location and type of 
proposed tree pro tection fencing. If the location of the tree 
pro tection fencing will be phased, indicate the loca tion o f the tree 
pro tection fencing for each corresponding phase. T ree pro tection 
fencing shall be minimum 5-foot tall metal unless o therwise approved 
by the city manager or designee. 
G . Supplemental specifications consistent with tree care industry 
standards that the project arborist or landscape architect has 
determined are necessary for the continued viability o f trees 
identified for preservation. 
H . Supplem ental specifications consistent with tree care industry 
standards that the pro ject arborist or landscape architect has 
determined are necessary fo r the continued viability o f stands 
identified for preserva tion . 
I. A general accounting of soil characteristics on site. A reas of existing 
or po tential tree growth limiting soils due to compaction, drainage, 
fertility, pH, contamination or o ther factors shall be clearly identified. 
Methods for improving areas o f tree growth limiting soils if tree 
planting is p roposed in those areas shall be specifically addressed . 
]. T he following inventory data in table or o ther such organized format 
corresponding to each open grown tree proposed for planting in the 
tree canopy site plan: 
1. T he assigned tree number; 
2. The genus, species and common name; 
3. The caliper (in inches for deciduous) or height (in feet for 
evergreen); 
Sec ti o n 1 0 - U rb a n Fo r es tr y Pl a n S t a ndard s 
C it y of T i ga rd U rb a n Fo r est r y M a nu a l 
City of TiganJ Urban l'orcstry Code Rc,·isions I \' olumc I \ ' I 44 
4. T he average mature tree canopy spread (in feet) as identified o n 1 Notes: 
any o f the tree lists in the Urban Fores try Manual. If an open 
grown tree approved for planting is not identified on any of the 
tree lists in the Urban Forestry Manual, then the project 
arborist or landscape architect shall determine the average 
mature tree canopy spread using available scientific li tera ture 
for review and approval by the city manager or designee; 
5. T he average mature tree canopy area (in square feet) calculated 
as follows: 
a. Average mature tree canopy area = (average mature tree 
canopy spread/ 2)2 x rr; 
6. T he proposed available soil volume (in cubic feet) for each tree 
according to the methodology in Section 12, part 2 of the 
Urban Forestry Manual. If the available soil volume is grea ter 
than 1000 cubic feet, then it is O K to note soil volume as 
simply "over 1000 cubic feet"; and 
7. Additional comments. 
K . The following inventory data in table or o ther such organized format 
corresponding to each stand proposed for planting in the tree canopy 
site plan: 
1. T he assigned stand number; 
2. T he genus, species and common name o f trees proposed for 
planting in the stand; 
3. T he average spacing (in feet) and to tal number o f each tree 
species proposed for planting in the stand; 
4. T he height (in feet) or container size (in gallons) o f each species 
proposed for planting in the stand; 
5. T he mature tree canopy dripline area o f the stand (in square 
feet) delineated at the outer edge o f the stand; and 
6. Additional comments 
L. Any supplemental specifications consistent with tree care industry 
standards that the project arborist or landscape architect has 
determined are necessary for the viability of trees proposed for 
planting. 
M. A summary in table or other such organized format clearly 
demonstrating the effective tree canopy cover that will be provided for 
the overall development site (excluding streets) and for each lo t or tract 
in the R-1, R-2, R-3.5, R-4.5 and R-7 districts (excluding streets) as 
follows: 
1. T he area (in square feet) o f the overall development site and 
each lot or tract; and 
2. T he effec tive tree canopy area that will be provided for the 
overall development site and each lot or tract which shall be 
considered the sum of the following: 
Sec t io n 1 0 - U rb a n Fo r e s tr y Pl a n S t a n da rd s 
Cit y o f T i gar d Ur b a n Fo r es tr y M a nu a l 
City o f Tigard Urban l'orcstry Code Rc,·isions I Volume IV I 45 
Page 10-9 
N otes: 
Page 10-10 
a. 
b. 
c. 
d. 
Double the canopy area (in square feet) of all open 
grown trees in the tree canopy site plan proposed for 
preservation within the overall development site and 
each lo t or tract (or associated righ t of way, excluding 
median trees). O nly trees with bo th a condition rating 
and suitability for preserva tion rating of 2 or grea ter 
are eligible for credit towards the effective tree 
canopy cover. T he overall development site and each 
lot or tract (or associated right o f way) with the larges t 
percentage of the trunk immediately above the trunk 
flare or root buttresses shall be assigned the effective 
tree canopy cover area for the corresponding tree; 
D ouble the canopy area (in square feet) of all stands 
in the tree canopy site plan proposed for preservation 
within the overall development site and each lot or 
tract (or associated righ t of way, excluding median 
trees). O nly stands with both a condition ra ting and 
suitability for preservatio n rating o f 2 or greater are 
eligible for credit towards the effective tree canopy 
cover. T he eligible tree canopy area shall be the 
portion directly above the overall development site 
and each lo t or tract (or associated right of way). T he 
canopy area of any stand grown tree with the largest 
percentage of the trunk immediately above the trunk 
fl are or root buttresses outside of the overall 
development site and each lot or tract (o r associated 
righ t o f way) shall not be eligible for credit towards 
the effective tree canopy cover requirement for that 
development site or lo t or tract; 
T he mature canopy area (in square feet) of all open 
grown trees in the tree canopy site plan, except for 
those from the native tree list in the U rban Forestry 
Manual, to be plan ted and maintained within the 
overall development site and each lot or tract (or 
associated righ t o f way, excluding median trees); 
1.25 times the mature canopy area (in square fee t) of 
all open grown trees from the native tree list in the 
Urban Forestry Manual in the tree canopy site plan to 
be plan ted and main tained within the overall 
development site and each lot or tract (o r associated 
right of way, excluding median trees); 
Sec ti o n 10 - U rb a n Fo r e s tr y Pl a n S t a nd a rd s 
C it y o f T i g a rd Ur b a n Fo r e s tr y M a nu a l 
Ciry of T igard Urban l'orcstry Code Rc,·isions I \ 'o lumc 1\' I 4(, 
--
e. 1.25 times the mature canopy area (in square feet) o f each stand in 
the tree canopy site plan to be planted and maintained within the 
overall development site and each lo t or tract (or associated right o f 
way, excluding median trees). The eligible mature tree canopy area 
shall be the portion directly above the overall development site and 
each lo t or tract (or associated right o f way); and 
f. Divide the tree canopy area (calculated per part 3.M.2.a-e above) 
for the overall development site and each lo t or tract by the to tal 
area of the overall development site and each lot or tract 
respectively to determine the effective tree canopy cover for the 
overall development site and each lo t or tract. 
N. The standard percentage of effective tree canopy cover for the overall 
development site shall be at leas t: 
1. 40 percent for R-1, R-2, R-3.5, R-4.5 and R-7 districts, except 
for schools (18.130.0500)); 
2. 33 percent for R-12, R-25, R-40, C-N , C-C, C-G , C-P, MUE, 
MUE-1, MUE-2, MUC, MUR and I-P districts, except for 
schools (18.130.0500)) ; and 
3. 25 percent for MU-CBD, MUC-1, I-L and I-H districts, and for 
schools (18.130.0500)) in all districts. 
0 . If the percent of effective tree canopy cover is less than the applicable 
standard percent in item n above for the overall development or less 
than 15 percent for any lo t or tract in the R-1, R-2, R-3.5, R-4.5 and R-
7 districts (when the overall development site meets or exceeds the 
standard percent effective tree canopy cover in item n), calculate the 
tree canopy fee required to meet the applicable standard percent 
effective tree canopy cover in item n above for the overall development 
site or 15 percent effective tree canopy cover for each lot or tract in the 
R-1 , R-2, R-3 .5, R-4.5 and R-7 districts (only if the overall development 
site meets or exceeds the standard percent effective tree canopy cover 
in item n but individual lots or tracts in the R-1, R-2, R-3.5, R-4.5 and 
R -7 districts do provide 15 percent effective tree canopy cover) 
according to the methodology in Section 10, part 4 of the Urban 
Forestry Manual. 
P . A signature o f approval and statement from the project arborist or 
landscape architect, attesting that: 
1. The tree preservation and removal site plan meets all o f the 
requirements in Section 10, part 1 o f the Urban Forestry 
Manual; 
2. The canopy site plan meets all of the requirements in Section 
10, part 2 of the Urban Fores try Manual; and 
3. T he supplemental report meets all of the requirements 1n 
Section 10, part 3 o f the Urban Forestry Manual. 
Part 4. Urban Forestry Plan- Tree Canopy Fee Calculation 
Requirements: 
A. The tree canopy fee shall be calculated as follows: 
Sec ti o n 10 - U rb a n Fo r es tr y Pl a n S t a nd a rd s 
C i t y o f T i g ard U rban Fo r es tr y M a nu a l 
- --~- ----- --
City of Tigard Urban Forestry Code 1\c,·isions I Volume IV I 47 
Notes: 
- - -
Page 10-11 
Note~: 
Sec . \ ppcndix 9 for 
l•: xample 
Supplemental Report 
Tcmplat<.: with 
formula for 
calculating the Tr<.:c 
Canopy l;cc 
Page 10-12 
1. 
2. 
I f the percentage of effective tree canopy cover is less than the 
applicable standard percentage in part 3, item n above for the 
overall development site find the di fference (in square feet) 
between the proposed effective tree canopy cover and the 
applicable standard effective tree canopy cover for the overall 
development site and multiply the di fference (in square feet) by: 
a. T he most recent wholesale m edian tree cost 
established by the PNW-ISA for a 3 inch diameter 
deciduous tree in the Willam ette Valley, O R divided 
by 59 square feet 
In cases where the overall development site m eets the standard 
percentage in part 3.N above yet the percentage o f effective 
tree canopy cover is less than 15 percent for any individual lo t 
or tract in the R-1, R-2, R-3.5, R-4.5 and R-7 districts, find the 
di fference (in square feet) between the proposed effective tree 
canopy cover and 15 percent effective tree canopy cover for 
each defi cien t lo t or tract and multiply the difference (in square 
feet) by: 
a. T he most recent wholesale median tree cost established 
by the PNW-ISA for a 3 inch diameter deciduous tree 
in the Willamette Valley, O R divided by 59 square feet 
P art 5. U rban F ores try Plan- Significant Tree Grove Preservation 
Con sideration s: 
A. Connects with and does not become isolated from the remaining 
portion o f the significan t tree grove on or off the site; 
B. Preserves the m ost dominant, resilient and healthiest native trees; 
C Preserves a diversity o f species, ages and sizes o f native trees; 
D. Preserves native unders tory and supports natural succession; 
E. P reserves and minimizes disturbance to native soils and tree roots; 
F D oes not preserve hazard trees or trees likely to soon become hazard 
trees particularly those subject to wind throw (low live crown ratio, 
high height to diameter ratio, suppressed root development) and 
exacerbated by newly created edges and / or removal of adjacent trees; 
and 
G. D oes not preserve trees currently or likely to soon be severely 
impacted by large scale weed, pest or disease outbreaks and / or 
changing site conditions (hydrology, ligh t, temperature, wind) . 
• Ef-END OF SECTION 
Sec t ion 1 0 - U r ba n Fo r e s tr y Pl a n Stan d a rd s 
Ci t y of Tiga rd U rb a n Fo r e s tr y M a nu a l 
City oiTigarJ Urban l;orcstry Code Rc,·isions I \ 'o lumc I\ ' I 4H 
Section 11 - Urban Forestry Plan Implem entation Standards 
P art 1. U rban Forestry Plan Implem entation Standards - Insp ection 
Requirem ents : 
A. After tree protection measures are installed and prior to any ground 
disturbance other than what is necessary for the installation of tree 
protection measures and erosion, sediment and pollutant controls 
measures, the project arborist or landscape architect shall perform a 
site inspection for tree pro tection measures, document 
compliance/ no n-compliance with the urban fores try plan and send 
written verification with a signature of approval directly to the city 
manager or designee within one week of the site inspection. 
B. Following the completion of item a above, the project arborist or 
landscape architect shall perform bimonthly (twice monthly) site 
inspections for tree protection measures during periods o f active site 
development and construction, document compliance/ non-
compliance with the urban forestry plan and send written verification 
with a signature of approval directly to the city manager or designee 
within one week of the site inspection. 
C. When the land use review type will result in the division o f land into 
multiple lo ts or tracts, the applicant shall provide on the building site 
plan for each resulting lot or tract, the information detailed in Section 
10, part 2.B-N of the Urban Forestry Manual consistent with the 
approved urban forestry plan. Prior to issuance o f any building 
permits for each resulting lot or tract, the project arborist or landscape 
architect shall perform a site inspection for tree protection measures, 
document compliance/ non-compliance with the urban forestry plan 
and send written verification with a signature o f approval with the 
building permit submittal documents. 
D . When the land use review type will result in the division o f land into 
multiple lots or tracts, the projec t arborist or landscape architect shall 
perform a site inspection for tree protection measures for all lots or 
tracts that are not proposed to be associated with a building permit, 
document compliance/ non-compliance \.vith the urban forestry plan 
and send written verification with a signature o f approval to the city 
manager or designee prior to the issuance of the first building permit 
resulting from the land use review type. 
E . Prior to final building inspection for any lot or tract with an ac tive 
urban forestry plan, the project arborist or landscape architect shall 
perform a site inspection, document compliance/ non-compliance 
with the urban forestry plan and send written verification with a 
signature of approval to the city manager or designee. 
N otes: 
Sec 1\ppcndix 10 for 
IO:xamplc Tree 
Canopy Site Plan 
(Section 1 0, Part 2) 
for an Individual Lot 
S e c t i o n I I - U r b a n F o r e s t r y P I a n I m p I e m e n t a t i o n S t a n d a r d s Page Il-l 
Cit y o f Ti ga rd U rb a n F o r es tr y Manu a l 
- -- - - -- -
City of Tigard Urban Forestry Code Rc,·isions I Volume 1\' I 49 
N ote>: 
See !\ laster l<'ecs and 
Charges schedule for 
current fees 
Page 11-2 
P art 2. U rban F ores try Plan Implem entation Standards - T ree 
Estab lishment Requirem ents: 
A. Prior to any ground disturbance work, the applicant shall provide a 
tree es tablishment bond for all trees to be planted per the approved 
urban fores try plan. The total bond amoun t: 
1. For subdivisions and minor land partitions shall be equivalent 
to the city's average cos t to plant and maintain a tree per the 
applicable standards in the Urban Fores try Manual for a period 
of two years after planting multiplied by the total number o f 
trees to be planted and maintained; and 
2. For all other land use review types shall be equivalent to the 
city's average cost to plant and main tain a tree per the 
applicable standards in the Urban Fores try Manual for a period 
of one year after planting multiplied by the total number of 
trees to be planted and maintained . 
B. Following final building inspection or upon acceptance by the city 
manager or designee when there is no final building inspection, the 
tree establishment period shall immediately begin and continue: 
1. In subdivisions and parti tions, for a period of two years or until 
such time as each lot is sold; and 
2. In all o ther land use review types, for a period o f one year. 
C. When the land use review type will result in the division of land in to 
multiple lo ts or trac ts, there shall be a separate tree es tablishment 
period for each resulting lo t or tract where trees are shown to be 
planted in the approved urban fores try plan . 
D. Following the applicable tree es tablishment period fo r each lot or 
trac t, the bond shall be correspondingly reduced based on tree survival 
following a site inspection, documentation of successful tree 
es tablishment and / or replacement according to item s E and F below, 
and receipt by the city manager or designee o f written verifica tion of 
findings and a signature of approval by the project arborist or 
landscape architect. 
E. For planted open grown trees, successful establishment shall be 
considered 80 percent survival of the open grown trees plan ted on the 
lot or trac t, and replacement of 100 percent of the remaining open 
grown trees planted on the lot or tract that did no t sun Tive. 
F. For planted stand grown trees, success ful establishment shall be 
considered survival o f at least 80 percent o f the original stand grown 
trees planted on the lot o r tract. 
G . If successful establishment for open grown trees is less than 80 
percent fo r any lot or tract, the applicable tree establishment period 
shall reset fo r that lot or tract and the es tablishment p rocess fo r open 
grown trees described in part 2.B-F above shall be repea ted until the 
successful establishment requirement for open grown trees is met. 
Sec t io n II- U rb a n Fo r e s t r y Pl a n Impl e m en t a t io n S t a nd a rd s 
C it y of T i g a rd Ur b a n Fo r e s t r y Ma nu a l 
City of Tigard Urbnn J.'orc:-; try Code Rc,·isions I Volume 1\' I 50 
H . If successful establishment fo r stand grown trees is less than 80 
percent for any lot or tract, the applicable tree es tablishment period 
shall reset for that lo t or tract and the establishment process for stand 
grown trees described in Part 2.B-F above shall be repeated until the 
successful establishment requirement for stand grown trees is met. 
Part 3. Urban Forestry Plan Implementation Standards- Urban Forest 
Inventory Requirements : 
A. Following documentation o f compliance with the urban forestry · plan 
by the project arborist o r landscape architect for each lo t or tract, the 
city shall collec t spatial and species specific data for each open grown 
tree and area of stand grown trees for inclusion in a publicly accessible 
inventory of trees. 
B. Prior to any ground disturbance work, the applicant shall provide a fee 
to cover the city's cost o f collecting and processing the inventory data 
for the entire urban fores try plan. 
END OF SECTION 
Sec ti o n 11- U rb a n F o r es tr y Pl a n Impl e m e nt a ti o n S t a nd a rd s 
Cit y o f Ti ga rd U rb a n F o re s tr y M a nu a l 
City of Tigard Urban Forestry Code Rc,·isions I Volume IV I 51 
N orcs: 
Sec t\ lastcr Fees and 
Charges Schedule for 
current fees 
Page 11-3 

P art 1. 
A. 
Section 12- Street Tree Soil Volume Standards 
Street Tree Soil Volume Standards - Soil Volume Requirements : 
Street trees required to be planted by chapter 18.7 45 shall be provided 
the following minimum soil volumes based on the width of the 
proposed right o f way measured from the edge of the street (excluding 
curb) towards the subj ect site: 
Minimum Soil 
Right of Way Width Volume Requirement 
(feet) (cubic feet per tree) 
Up to 10 400 
Over 10 up to 12 500 
Over 12 up to 14 600 
Over 14 up to 16 700 
Over 16 up to 18 800 
Over 18 up to 20 900 
Over 20 1000 
Part 2. Street Tree Soil Volume Standards- Soil Volume Calculation 
Requirements : 
A. For open soil volumes, soil depth is assumed to be 3 feet if the tree 
canopy site plan (per 18. 790.030.A.3) and supplemental report (per 
18.790.030.A.4) demonstrate that the tree will not be planted in an 
area of tree growth limiting soil or the area o f tree growth limiting soil 
will be adequately amended to a depth o f 3 feet in the specified 
planting area. 
B. Areas of tree growth limiting soils that have no t been adequately 
amended shall not be eligible for credit towards the minimum soil 
volume requirements in part 1 of this section. 
C. For covered soil volumes, the soil depth is equal to the depth of the 
covered soil volume as demonstrated by the soil volume plan in part 3 
o f this section. 
D . Soil volumes for open soil volumes shall be calculated (in cubic feet) 
by measuring the open soil volume area (in square feet) times an 
assumed soil depth of 3 feet. 
E . Soil volumes for covered soils volumes shall be calculated (in cubic 
feet) by multiplying the area of the covered soil volume times the depth 
o f the covered soil volume as demonstrated by the soil volume plan in 
part 3 of this section. 
F. The total soil volume provided for a tree shall be calculated (in cubic 
feet) by adding the available open soil volume (per part 2.C above) to 
the available covered soil volume (per part 2.D above) within a 50 foot 
radius of the tree. 
Sect i o n 1 2- S tr ee t Tree So il Volume S tandard s 
City o f Tigard U rban Forestry M a nu a l 
~ -~-- -------- --
City of Tigard Urban Forestry Code Revisions I Vo lume IV I 53 
Notes: 
Sec 1\ ppcndix 11 for 
three l•:xamplc Soil 
Volume Calculations 
for Street T rees 
Page 12-1 
N ote>: 
Sec , \ ppcndix 12 for 
I ':xamplc Soil 
\' olume Plan 
Sec ,\ppcndix 14 for 
two alternati ve 
I ~ x amplc Covered 
Soil \ ' olume Plan 
Drawings and an 
I ~ xamplc Covered 
Soil Specification for 
Street Trees 
Sec .\ppcndix 13 for 
l·: xamplc Soil 
\ ' o lumc Plan for a 
Single Lot 
Page 12-2 
G . 
H . 
I. 
The open and covered soil volumes are considered "available" to a 
tree only when they are directly connected to the tree by a continuous 
path o f no less than 3 feet in width. 
In addition, covered soil volumes are considered "available" to a tree 
only w hen demonstrated as available by the soil volume plan in part 3 
o f this sec tion. 
All soil volumes calculated per this section shall be displayed for each 
corresponding tree in the reguired supplemental report. 
Part 3. Street Tree Soil Volume Standards - Soil Volume Plan 
Requirements: 
A. A soil volume plan shall be reguired for any street tree reguired to be 
planted by chapter 18.745 if a covered soil volume is proposed to be 
used to meet any portion of the minimum soil volume reguirements in 
part 1 o f this sec tion. T he soil volume plan shall include all items in 
part 3.B-E below. 
B. A standard size D (24" x 36"), a reduced legal size and a PDF soil 
volume plan by a registered landscape architect (the project landscape 
archi tect) that includes all of the following elements: 
c. 
1. D ate o f drawing or las t revision; 
2. North arrow; 
3. Bar scale; 
4. Site address or assessor's parcel number; 
5. T he name, address, telephone number, email address and 
license number o f the pro ject landscape architect; 
6. T he location o f property lines or proposed property lines if 
different from exis ting; 
7. T he loca tion of proposed building footprints, utilities and 
irriga tion, streets and other paved areas; 
8. T he assigned numbers (consistent with the tree canopy site plan 
and supplem ental report of a concurrent urban forestry plan) of 
all trees; 
9. T he location o f each open soil volume area and each covered 
soil volume area considered "available" fo r each tree; and 
10. T he City of Tigard Example Covered Soil Volume Plan 
Drawings and Specifica tions unless o therwise approved by the 
city manager or designee. If reguired fo r clari ty, this 
information may be detailed on a separate plan sheet. 
\\ !hen the land use review type will result in the division o f land into 
multiple lots or tracts, the applicant shall provide on the building site 
plan fo r each resulting lot o r tract, the information detailed in - part 
3.B.1-1 0 of this section consistent with the approved soil volume plan 
and a signature o f approval from the project landscape architect. 
Sec ti on 12- St r eet Tree Soi l Vo lum e S t a nd ar d s 
Cit y of Tigard Urba n Fore s try Manual 
Ciry of T igard Urban l ;urc~try Code Re,· i :-~ i on~ I Volume 1\' I 54 
D. The project landscape architect shall document compliance/ non-
compliance (including but not limited to materials receipts and 
observations from site inspections) with the approved soil volume plan, 
and send written verifica tion with a signature o f approval to the city 
manager or designee prior to final building inspection for all lo ts, 
parcels, or tracts associated with each particular tree. \\!hen the land 
use review type will result in the division o f land into multiple lo ts or 
tracts, the project landscape architect shall provide the 
documentation/verification described above for all lo ts or tracts that 
are not proposed to be associated with a building permit prior to the 
issuance o f the first building permit resulting from the land use review 
typ e. When the land use review type does no t involve a building 
permit, the project landscape architect shall provide the 
documentation/verification described above prior to final acceptance 
by the city manager or designee. 
E. If any subsequent modifications to an approved soil volume plan is 
required to meet the minimum soil volume requirements in part 1 o f 
this section, a revised soil volume plan that meets the requirements o f 
part 3 o f this section shall be provided that reflect the revisions. 
END OF SECTION 
Sec t io n 1 2 - S tr ee t Tree So il Vo lum e S t a nd a rd s 
C it y o f T i ga rd U rb a n F o r es tr y M a nu a l 
City of Tigard Urban Forestry Code Rc,·isions I Volume I\' I 55 
N otes: 
Page 12-3 

Section 13- Parking Lot Tree Canopy Standards 
Part 1. P arking Lot Tree Canopy Standards -Parking Lot Tree 
Requirements: 
A. 
B. 
c. 
D. 
E. 
F. 
Parking lot trees shall be planted in a manner consistent with tree care 
industry standards. 
Parking lot trees shall have a minimum caliper of 1 112 inches (for 
deciduous) or height of a 6 feet (for evergreen) at the time of planting. 
Parking lot tree species shall be from the parking lot tree list, unless 
otherwise approved by the city manager or designee. 
Parking lot trees shall not be planted with the center of their trunks 
closer than 3 feet from any hard surface paving, including curbs. 
Parking lo t trees shall be evenly distributed wi thin the parking area, 
and no greater than 6 feet from the parking area. 
Parking lot trees shall be provided a minimum o f 1000 cubic feet of 
soil volume per tree. 
Part 2. Parking Lot Tree Canopy Standards - Soil Volume Calculation 
Requirements : 
Notes: 
Sec 1\ ppcndix 3 for 
Parking I .o t Tree I .ist 
A. Soil volumes for open soil volumes shall be calculated (in cubic feet) Sec Appendix 15 for 
by measuring the open soil volume area (in square feet) times an three J•:xamplc Soil 
assumed soil depth of 3 feet. Volume Calculations 
B. Soil volumes for covered soils volumes shall be calculated (in cubic for Parking Lot T rees 
feet) by multiplying the area of the covered soil volume times the 
depth o f the covered soil volume as demonstrated by the parking lot 
tree canopy plan in part 3 of this section. 
C. The to tal soil volume provided for a tree shall be calculated (in cubic 
feet) by adding the available open soil volume (per part 2.A above) to 
the available covered soil volume (per part2.B above) within a 50 foot 
radius of the tree. 
D . T he open and covered soil volumes are considered "available" to a 
tree only when they are directly connected to the tree by a continuous 
path of no less than 3 feet in width, and demonstrated as available by 
the parking lot tree canopy plan in part 3 of this section. 
E . All soil volumes calculated per this section shall be displayed for each 
corresponding tree in the supplemental report (per 18. 790.030.A.4) 
when an urban fores try plan is concurrently required. 
Part 3. Parking Lot Tree Canopy Standards - Parking Lot Tree Canopy 
Plan Requirements : 
A. A parking lot tree canopy plan shall be required unless the city 
manager or designee detennines the requirements of a concurrent 
urban forestry plan per chapter 18.790 will meet the equivalent 
standards in part 3 of this section. The parking lot tree canopy plan 
shall include all items in part 3.B-E below. 
-
S ec ti o n 1 3 - P a rkin g L o t Tr ee Can o p y Standard s 
Cit y o f Ti ga rd U rban Fo re s tr y Manual 
City of Tigard Urban Forestry Code Rc,·isions I Volume IV I 57 
Sec ,\ppcndix 16 for 
l·:xamplc Parking l.ot 
Tree Canopy Plan 
-
Page 13-1 
No te>: 
Sec 1\ppcndix 17 for 
two alternative 
J•:xamplc Covered 
Soil \ 'o lumc Plan 
Drawings and an 
J•:xamplc Covered 
Soil Specification for 
Parking ! .or Trees 
Sec , \ ppcndix 18 for 
J•: xamplc Parking Lot 
that 1\ k cts the 30% 
i\ linimum Canopy 
Cover Req uirement 
per Code Section 
18.745.050. 1·: .1.a.4 
Page 13-2 
B. 
c. 
A standard size D (24" x 36"), a reduced legal size and a PDF parking 
lo t tree ca nopy plan by a registered landscape architect (the project 
landscape architect) that includes all o f the following elements: 
1. D ate o f drawing o r last revision; 
2. North arrow; 
3. Bar scale; 
4. 
5. 
6. 
7. 
8. 
9. 
10. 
11. 
12. 
13. 
14. 
15. 
Site address or assessor's parcel number; 
The name, address, telephone number, email address and 
license number o f the project landscape architect; 
The location o f property lines or proposed property lines if 
differen t from existing; 
The loca tion o f proposed building footprints, utilities and 
irrigation, streets and o ther paved areas; 
T he loca tion o f areas o f tree growth limiting soils due to 
compaction, drainage, fertili ty, pH, contamination o r o ther 
fac tors; 
Methods for improving areas o f tree growth limiting soils if tree 
planting is proposed in those areas. If required for clarity, this 
information may be detailed on a separate plan sheet; 
The loca tion o f all parking lo t striping and the location o f the 
limits o f the parking area, which includes all parking spaces, all 
landscape islands and all parking aisles; 
Assigned numbers (consistent with the tree canopy site plan per 
18.790.030.A.3 and supplemental report per 18.790.030.A.4 o f a 
concurrent urban fores try plan) o f all parking lo t trees; 
T he location, species and caliper (in inches for deciduous) o r 
height (in fee t fo r evergreen) o f all parking lo t trees; 
D epiction o f the average mature tree canopy spread (in feet as 
identified on any o f the tree lists in the Urban Fores try Manual) 
for each parking lo t tree. If a parking lo t tree is no t identified 
on any o f the tree lists in the U rban Fores try Manual, then the 
project arborist or landscape architect shall determine the 
average m ature tree canopy spread using available scientific 
li terature fo r review and approval by the city manager o r 
designee; 
T he location o f each open soil volume area and each covered 
soil volume area considered "available" for each tree; and 
If covered soil volumes are proposed to meet any portion o f 
the soil volume requirem ent in part 1.F o f this section, the City 
o f Tigard Example Covered Soil Volume Plan Drawings and 
Specifica tions unless o therwise approved by the city manager or 
designee. If required for clarity, this informatio n may be 
detailed on a separate plan sheet. 
A summary 1n table or other such organized format clearly 
demonstrating the proposed percen t tree canopy cover at maturity 
directly over the parking area as follows: 
1. T he area (in square feet) of the parking area as shown in the 
parking lo t tree canopy plan; 
Sec ti o n 1 3- P a rk i n g L o t T r ee Ca n o p y Sta nd a rd s 
C it y o f T i ga rd U rb a n Fo r est r y M a nu a l 
City of Tigard Urban l'oresrry Code Re,·isions I Volume I \ ' I 58 
2. T he average mature tree canopy area for each parking lot tree 
as follows: 
a. Average mature tree canopy area= (average mature tree 
canopy spread/ 2)2 x n; 
3. T he total combined mature tree canopy area (in square fee t) o f 
all parking lot trees less the percen tage not directly over the 
parking area; and 
4. The total combined mature tree canopy area directly over the 
parking area (in square feet) divided by the parking area. 
D . T he project landscape architect shall document compliance/ non-
compliance (including but not limited to materials receipts and 
observatio ns from site inspections) with the approved parking lo t tree 
canopy plan, and send written verificatio n wi th a signature o f approval 
to the city manager or designee prior to final building inspection or 
prior to final acceptance when there is no final building inspection. 
E . If any subsequent modifications to an approved parking lot tree canopy 
plan is required, a revised parking lot tree canopy plan that meets the 
requirements o f part 3 o f this section shall be provided that reflect the 
reVlSlOnS. 
END OF SECTION 
Sec ti o n 1 3 - P a rkin g L o t T r ee Can o p y Standard s 
C it y o f Ti ga rd U rban F o r es tr y Manual 
City o f Tigard Urban Forestry Code Rc,·isio ns I \'olumc IV I 59 
Note~: 
Page 13-3 

City oETigard 
Tree Risk Assessment Form 
II azard Rating: 
Probability + The Target + Size of 
of Failure Area Dcfccti\'e Part 
0\'crall Risk 
Rating 
Recommended H azard Tree Abatement Procedures: 
Property Address: __________________ _ 
Location: D Public D Private D Right-of-Way 
Protected T ree: D Yes D No 
Tree Species: _____________________ _ 
Diameter at Breas t H eight (DBH): ____________ _ 
T ree H eight: _____________________ _ 
Crown Spread :. ____________________ _ 
T ree Part Subj ect of Evaluation: _____________________________ _ 
Diameter o f Subject Tree Part:. _____________________________ _ 
Distance to Target o f Subject Tree Part:. __________________________ _ 
Len~h ofSu~ect Tree Patt. _____________________________ _ 
Target: ______________________________________ _ 
O ccupancy ofTarget: D Occasional Use D Intermittent Use D Frequent Use D Constant Use 
D ate o f Evaluation: 
T ree Risk Assessor: 
ISA N umber: 
Tree Risk Assessor Signature: _______________________ _ 
*Fill out this and supplemental rating form completely and attach: 1) photos of the tree; 2) an aerial photo showing the 
location of the tree on the subject property; and 3) a supplemental tree risk assessment report more fully describing 
whether the definition of hazard tree has been met and, if necessary, recommended hazard tree abatement procedures. 
Appendix 1 
City of Tigard Urban l'orcstry Code Re,·isions I \'olumc IV I 61 

!Ei.Uii IL41 ,._
Low Defect is not likely to lead to 
1 point I imminent failure, and no further action is required. l n many cases, 1 
1 
defects mighr not be recorded. 
Moderate 
2 points 
Moderately 
Hig h 
3 points 
High 
4 points 
Extreme 
5 points 
O ne or more defects areas well-
established but typically do not lead to 
failure for :-;cveral years. Corrccti\'c 
action might· be useful to prevent 
future problems bur only if time and 
money arc available. Not the highest 
priority for action, these arc retain and 
monitor situations used to inform 
budget and work schedules for 
subsell uent years. 
One or more defects areas well-
established, but not yet deemed to be 
a high priority issue. Additional 
testing may be required or, the 
I 
assessor may feel the problems are 
nor serious enough to warrant 
immediate action, but do warrant 
placing the tree on a list o f trees to be 
inspected more regularly. These are 
Retain and Monitor trees. 
The defect is serious and imminent 
failure is likely and correcti\'C action is 
required immediately. These cases 
re<-juire treatment within the next few 
days or weeks. 
The tree or component part is already 
failing. An emergency situation where 
treatment is required today. 
Minor branch o r crown dieback, small wounds, minor defects. 
Several defects present. 
• Shell wall exceeds tninimum rel.juirement 
• Cracks initiated but no extensive decay 
• Cavity opening o r o ther stem damage less than 30° u of circumference 
• Crown damage or breakage less than 50" o o f canopy (30"" in pines) 
• Dead crown limbs with fine twigs attached and bark intact 
• Weak branch union such as major branch o r codominant stem with 
included bark 
• Stem gird ling roots with less than 40" o of circumference compressed 
• Roo t damage or root decay affects less than 33° o of roots within the 
critical zone I 
• Standing dead tree that is recently dead (sti ll has fine twigs) and no 
other significant defects 
Areas of decay that may be expand ing; trees that have developed a recent 
but not yet critical lean; cracks noted but may be stable; edge trees that 
tnay adapt and become more stable. 
O ne or more major defects present. 
• Insufficient shell wall thickness 
• Large cracks, possibly associated with other defects 
• Cavity opening greater than 30° o o f circumference 
• Crown damage or breakage more than 50" o of canopy (> 30° o in 
pines) 
• Dead crown limbs with no fine twigs and bark peeling away. May be 
some saprophytic fungal evidence 
• Weak branch union has crack(s) or decay 
• Stem girdling root affects 40° o or more of trunk circumference 
• More than 33° o o f roots are damaged within rhc critical zone 
• Tree is leaning. Recent root breakage, or soil mounding, or cracks, 
or ex tcnsi,·c decay evident 
• Standing dead tree, has very fe\\· fine twigs, and no other significant 
defects 
Multiple high or extreme risk defect s present. 
• Shell wall is already cracked and failing 
• Major cracks already open, such as hazard beams or split trunks 
• More than 30% of circumference defective and cracks or decay 
obvious 
• Dead crown limbs, no fine twigs, no bark, decay present 
• Weak branch union has crack(s) and decay 
• Leaning tree with recent root failure, soil mounding, and cracks 
or ex tensive decay 
• Dead branches hung up or partly failed 
• Visual obstruction of traffic signs/ lights at intersections 
• Any partly failed component or whole tree 
• Standing dead trees that have been dead for more than one season 
with 
I ~ 
'--------'-----------------~iple defects such as cracks, decay, damaged roots,_ shedding bark 1 
Appendix 1 
City of Tigard Urban Forestry Code Rc,·isions I Volume IV I 63 
Low 
1 point 
Moderate 
2 points 
Moderatel 
y 
High 
3 points 
High 
4 points 
~ 
Sites rated at one point arc very rarely used for any long period o f time, and people passing through the 
area (regardless of how they travel) do not spend a lo t o f time within th e striking range of the tree. 
There arc no valuable buildings or other facilities within striking range. l·~xamplcs arc seldom used back 
country roads or trail s, seldom used overflow or long- term parking, industrial areas where workers dri ve 
machin es (trucks, forklifts, tractors) with substantial cab protection; natural or wilderness areas; 
transition areas wi th limited access; remote areas o f yards, parks, or private lands open for public usc 
within set hours. All of these sites have relatively low occ':'_pancy within any one day . 
Valuable buildings arc at the edge off the striking distance, so they would not be seriously damaged even 
if the tree did fall down. The si re has people within striking range occasionally, meaning less than 50% 
of the time span in any one day, week, or month, and do not stay within striking range very long. 
J•:xan1plcs include areas that arc used seasonall y; tnorc rctnorc areas of catnping areas or parks; tninor 
rural roads; picnic areas; low to moderate usc trail s; most park and school playgrounds.** Moderate to 
low usc parks, parking lots wi th daily usc; secondary roads and intersections, di spersed camping sites, 
moderate to high usc trail s, works and / or storage yard s. 
The site has valuable buildings within striking range. People arc within striking range more than 50% of 
the time span in any one day, week, or month, and their exposure time can be more than just passing 
by. Examples include secondary roads, trail s, and access points; less commonly used parking areas and 
trail s within parks; trail s alongside fairways, bus stops. 
'I 'he highest rated targets havc a) a building within striking range frequently accessed by people, o ften 
for longer periods of tim e, or high volumes of people coming and going within striking range. Valuable 
buildings or other structures within strik ing range that would suffer major structural damage in the 
event of tree fai lure or; b) people within striking distance o f the tree, or both, seven days a week, aU year 
long, and at all times of the day. I ·:xamples include main roads, the busiest streets or highways; high 
volume intcrscctions power lines/ path s through busy open space areas and parks; short-term parking 
constantly in usc; institutional buildings such as police stations, hospitals, fire stations; shopping areas; 
highl y used walking trail s; pick up and drop off points for commuters; golf tees and b'rcens; emergency 
access routes and / or n1 arshalling areas; handicap access areas; high usc camping areas, visitor centers or 
shelters; residential buildings; industrial areas where workers take outside breaks; development sites 
where work activi ty wi thin striking range l a~t~ tnorc than a few hours at a tim e. 
--l 
- -· 
-+ 
*There arc very speci fic safe work practi ces required when working cl ose to Power I .incs. These vary depending on location, but 
all employ similar principles. 
**It is rcC<>!,'11izcd that th ere is a tendency to rate playgrounds higher simply because children arc involved. !\los t playgrounds arc 
occupied for short periods of time in daylight hours. Overall , their usc is infrequent when compared to o ther locations such 
a~ busy stn:cts. 
(~~ 
1 point Branches or stems up to 10 centimeters (4 inches) in diameter 
I I 2 points Branches or stems between 10 to 50 centim eters (4 to 20 inches) in diameter. 
3 points r Branches or stems greater than 50 centimeters (20 in ches) in diameter. 
*In some cases, there may be large areas of sloughing back bark, dwarf mistletoe brooms, branch stubs, or large bird nes ts in 
cavi ties th at pose a ri ~ k. The assessor must usc his or her judgtnent to assign a number to these cotnponents. In general, th e 
lowest rating (1 point) is rcscrvcd for component parts th at would not crea te much impact on a person or propcrty if it were to 
fail. The highes t rating is used for part> that have the potential to kill people or seriously damage property. 
Appendi.-x 1 
City oi Tigard Urban h>rcstry Code Rc,·isions I \'olumc 1\' I (,4 
[ffJ!ItWG'\fl~-· 
Ris_;--1 Risk C!uegory Interpreution 11nd Implicll tions 
RRting 
3 Low1 
:=t:w2 
ow3 
6 l .Moderate 1 
7 Moderate 2 
8 1\ loderate 3 
--
9 H igh 1 
10 lligh 2 
11 l l igh 3 
12 t l ~x treme 
Insignificant - no concern at all . 
lnsij,mificant - very minor issues. 
Insignificant- minor issues not of concern for many years yet. 
Some issues but nothing that is likely to cause any problems for ano ther 10 years 
or more. 
Well defined issues - retain and monitor. Not expected to be a problem 
least another 5-1 0 years. 
\Veil defined issues- retain and monitor. Not expected to be a problem 
least another 1-5 years. 
The assessed issues have now become very clear. The tree can still reason 
retained as it is not likely to fall apart right away, but it must now be moni 
annually. A t this stage, it may be reasonable for the ri sk manager/ owner 
public education sessions to inform people of the issues and prepare them 
reality that part or the entire tree has to be removed . 
The assessed issues have now become very clear. The probability of failu 
now getting setious, or the target rating and / or sire context have changed 
that mitigation measures should now be on a schedule wi th a clearly dcftn 
timeline for action. There may still be time to inform the public of the wo 
being planned, but there is not enough rime to protracted discussion abou 
whether or not there arc alternative ontions available. 
The tree, or a part o f it has reached a stage where it could fail at any time. 
Action to m itigate the risk is required within weeks rather than m on 
By th is stage there is no t time to hold public meetings to discuss the issue 
reduction is a clearly defined issue and although the owner may wish to in 
the public of the planned work, he/ she should get on with it to avoid clea 
foreseeable liabili ties. I This tree, or part of it, is in the process of failing. Immediate action is 
required . All other, less s i ~:,mificanr tree work should be suspended, and r' 
work areas sho uld be closed o ff, until the risk issues have been mitiga ted. 
might be as simple as removing the critical part, drastically reducing ovcra 
height, or taking the tree down and cordoning off the area until final clean 
complete removal can be accomplished. The immediate action required is 
ensure that the clearl y identified ri sk of harm is eliminated. For areas hit b 
severe sto rms, where many ex treme tisk trees can occur, drastic pruning a1 
partial tree removals, foll owed by barriers to contain traffic, would be an 
acceptable first stage o f ti sk reduction. There is no time to in form people 
worry about public concerns. Clearly defined safety issues preclude furthe 
discussion. 
)rat 
)fat 
tbly be 
ored 
) hold 
for the 
; IS 
;uch 
d 
rk 
hs. 
Risk 
orm 
ly 
)ads or 
This 
I tree 
up, or 
to 
)' 
1d/ or 
or 
r 
T he Table shown above outlines the interpreta tion and implications of the risk ratings and associated risk categories. This table 
is provided to inform the reader about these ri sk catcgoties so that they can better understand any risk aba tement 
recommendations made in the risk assessment report. 
Notes: ______________________________________________________________________________________________ __ 
.Appendi'-: 1 
City of Tigard Urban Forestry Code Revisions I Volume 1\' I 65 

D 
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0 
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3 (') 
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c-
..... 
Appendix 2 
Street Tree List - Small Stature Trees 
u to 25' in hei ht at maturi 
Pap~r!mk Map!!.: A cergrismm 25' 25' 491 sq. ft. all Yes* 
Tatarian Maple Acer tatmic11m 20' 20' 314 sq. ft. all Yes 
Trid~:nt Mapk Acer b11ergeran11m 25' 20' 314 sq. ft. all Yes 
Serviceberry A melanchier x grandijlom 25' 15' 177 sq. ft. well drained Yes 
W~:mm Sm~i~~:b~m: A melanchier alnijolia 20' 20' 314 sq. ft. loam Yes 
llm~:ri~an !I!.Jrnb~:l!m Cmpima caroliniana 25' 20' 314 sq. ft. all No 
Eastern Redbud Cercis canadmsis 25' 25' 491 sq. ft. all Yes 
G!uryb!.!~!.:r 'h~:~: C!erodmdmm tlichotom11m 20' 20' 314 sq. ft. all Yes 
KQ!.!~il Qo~QOQ COr?/ liS feoi/Ja 25' 25' 491 sq. ft. all Yes 
F!QW!.:IIIl!l: QQgJ.VQQg Com11s j101ida 25' 25' 491 sq. ft. all Yes 
Lavalle llawthorne Cmtaeg11s x lava/lei 25' 20' 314 sq. ft. all Yes 
Black !lawtbQ!ne Crataeg11s do11glasii 25' 20' 314 sq. ft. all Yes 
Golden Desert Ash Fraxin11s excelsior 'Golden Desert' 20' 20' 314 sq. ft. all Yes 
Flow~:ritl!l: 1\~h Fraxin11s omus 25' 25' 491 sq. ft. all Yes 
Merrill Ma!ffiolia Magnolia x loebmli 'Merrill' 25' 25' 491 sq. ft. all No 
Somhem l\bgtlQiia Magnoliagmndijlo1a 'Victoria' or 'Little Gem' 25' 25' 491 sq. ft. all No 
Prariefire Crabapple Mal11s spp. 'Prariefire' 20' 20' 314 sq. ft. all Yes 
S tewartia psmdocamellia 25' 25' 491 sq. ft. loam No 
S tryaxjaponiclls 25' 25' 491 sq. ft. well drained Yes 
S n'n a retimlata 20' 177 s . ft. well drained Yes 
*These trees have been approved by Po rtland General Electric 
(PG E) for planting beneath overhead powerlines 
peeling bark, tolerates gome shade 
tolerant of urban stresses 
tolerant of urban stresses 
white flowers, edible fruit 
native to Portland metropolitan region 
needs ample water 
pink flowers in spring before leaves emerge 
colorful flowers in summer, blue berries in fall 
shade tolerant 
large number of varieties available 
white flower~ in May, orange-red fruit persist 
into Winter 
native to Portland metropolitan region, has 
thorns 
golden twigs 
fragrant flower~ 
---- fragrant white flowers 
broadlea f evergreen, large fragrant white flowers 
di sease resistant 
needs ample water 
white flowers hang down from branche~ 
sho 
1  I~dv~ Map!~ 
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t o l e r a n t  o f  u r b a n  s t r e s s e s  
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d e n s e  c r o w n  
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f r a g r a n t ,  w h i t e ,  p e n d u l o u s  f l o w e r s  
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n a t i v e  t o  P o r t l a n d  m e t r o p o l i t a n  r e g i o n ,  r e q u i r e s  
m o i s t  s o i l  a n d  s o m e  s h a d e  
d o v e - l i k e  f l o w e r s  
s m o g  t o l e r a n t  
t o l e r a n t  o f  u r b a n  s t r e s s e s  
w h i t e ,  f r a g r a n t  f l o w e r s  
b r o a d l e a f  e v e r g r e e n ,  m a n y  o t h e r  v a r i e t i e s  
a v a i l a b l e  
w h i t e ,  m i d s u m m e r  f l o w e r s  
e x f o l i a t i n g  b a r k  t e x t u r e  i s  a t t r a c t i v e  
b e a u t i f u l  b a r k  a n d  f a l l  c o l o r  
f r a g r a n t  l e a v e s  a n d  f r u i t  
m a n y  v a r i e t i e s  a v a i l a b l e  
n a t i v e  t o  P o r t l a n d  m e t r o p o l i t a n  r e g i o n  
p e s t  a n d  d i s e a s e  r e s i s t a n t ,  s u b s t i t u t e  f o r  
A m e r i c a n  E l m  
Red Maple Acer mbmm 
Ilackberw Celtis occidmtalis 
!.ll.!~OP!:lln B~:~:~h Fagus s)'lvatica 
D \Vhitc Ash Fm:·dnus amen'cana 
..:2 Oregon Ash F ro.xinus latifolia 
c Green Ash F mximu pennsylvanica ~ 
riG 
"' a. Mair;knhair Tr~~ Ginkgo btloba 
c lloneylocust Gleditsia tliacanthos var. inermis a-
"' K~nm~k)' Coffcct!:~!: GJ•nmodadtls dioims :> 
a· Tulip Tree Ln'odendron tulipifera 
il g 
Southern M3gnolia Magnolia grandijlora 
c, · Blackg!.!m i'{)·ssa S)'lvatica 0.. 
r. 
;;::; 
" 
London Planetree Platanus x acerifolia 'Bloodgood' 
" Scotch Pine Pinus sylvtstlls ;;, · (5," Oregon \Vhite Oak Q uerr:11s gaf'l)•ana ~ 
Willow Oak Qtmrus phellos 
-- lill!....Qak Querr:tts ntbro c' 
c 6m~ri~a!ll.1mkn Tt!ia amen'catta 3 
"' ::lt!:rling ~iiY!:I Linden Tilia tommtosa 'Sterling Silver' 
< b.cl.!illYa Zelkova smvta 
c-
"' 
Appendix 2 
Street Tree List - Large Stature Trees 
over 40' in hei ht at maturi 
50' 40' 1256 sq. ft. any No 
45' 35' 962 sq. ft. any No 
50' 40' 1256 sq. ft. well drained l 0 
60' 45' 1590 sq. ft . any No 
60' 30' 707 sq. ft. any No 
50' 40' 1256 sq. ft. any No 
60' 45' 1590 sq. ft. any No 
45' 35' 962 sq. ft. any No 
65' 50' 1963 sq. ft . any l 0 
60' 30' 707 sq. ft. any No 
70' 60' 1963 sq. ft. any No 
45' 25' 491 sq. ft. any No 
50' 40' 1256 sq. ft. any No 
50' 40' 1256 sq. ft . any No 
65' 50' 1963 sq. ft. any No 
60' 45' 1590 sq. ft. any No 
60' 45' 1590 sq. ft. any No 
60' 30' 707 sq. ft. any No 
45' 707 sq. ft. any No 
1963 s . ft. No 
.. 
many large stature varieties available 
tolerant of urban stresses, deep rooted 
beautiful bark 
plant seedless varieties 
native to Portland metropolitan region 
plant seedless varieties 
many large stature varieties available, plant males 
only 
thornless, tolerant of urban stresses 
fragrant flowers 
beautiful fa ll color 
broadleaf evergreen, large fragrant white flowers 
beautiful fall color 
disease resistant, pollution tolerant 
evergreen conifer, striking orange bark 
native to Portland metropolitan region 
tolerant of urban stresses 
beautiful fall color 
tolerant of urban stresses 
dark green leaves with silver undersides 
attractive shade tree 

Appendix 3 
Bigleaf Maple Acer macropi?JIItlm 65' 50' 1963 sq. ft. any No native to Portland metropoHtan region 
Red l\laple A cermbmm 50' 40' 1256 sq. ft. any No brilliant red fall color 
European Beech Fagus syi!Jatica 50' 40' 1256 sq. ft. well drained No beautiful bark 
White ,\sh Fraxi1111s america11a 60' 45' 1590 sq. ft. any No plant seedless varieties 
c: 
~~ · (~reen ,\sh Fra:xim!S pw11sylua11ica 50' 40' 1256 sq. ft. any No plant seedless varieties 
£, many large stature varieties available, plant 
dO Maidenhair Tree Ginkgo biloba 60' 45' 1590 sq. ft. any No males only 
" 2.. Kentucky Coffeetree Gym11oclarlus rlioicus 65' 50' 1963 sq. ft. any No fragrant fl owers 
c 
a- broadleaf evergreen, large fragrant white 
" ::l Southern l\lagnolia Magnolia granrliflora 70' 60' 2826 sq. ft. any No flowers 
Q , \ ustrian Pine Pinus nigra 55' 40' 1256 sq. ft. any No evergreen coni fer 
" ~ Eastern White Pine Pinus strobus 70' 40' 1256 sq. ft. any No evergreen coni fer 
" 
Scotch Pine Pim!S syluestris 50' 40' 1256 sq. ft. any No evergreen conifer, striking orange bark g_
" 
London Plan~:tree Plata/IllS x amifolia 'Bloodgood' 50' 40' 1256 sq. ft. any No disease resistant, pollution tolerant 
;::l 
c: Oregon \'Vhite Oak Q uerms garrya11a 65' 50' 1963 sq. ft. any No native to Portland metropoHtan region 
~ Willow Oak Quercus phellos 60' 45' 1590 sq. ft. No tolerant of urban stresses 0 any 
~ ----Red Oak Quercus mbra 60' 45' 1590 sq. ft. any 0 beautiful fall color 
< graceful vase shaped tree, disease resistant 0 
c , \!;colad~ Elm Ulmus 'Morton' 70' 60' 2826 sq. ft. any No substitute for American elm 3 
r. 
Lacebark f\lm Ulmus parvifolia 60' 50' 1963 sq. ft. No interesting mottled bark 
< 
any 
:::! 
rounded spreading crown, disease resistant 
Pioneer Elm Ulmus 'Pioneer ' 50' 50' 1963 sq. ft. any No substitute for American elm 
Oregon Myrtle Umbe/111/aria califomica 70' 50' 1963 sq. ft. any No broadleaf evergreen 
Zclkova Zelkova sm-ata 65' 50' 1963 s . ft. No attractive shade tree 

Appendix 4 
Columnar Trees 
read of less than 2 0 feet at maturi 
Armstronl? Ml!nle A cer mbmm 'Armstrong' 45' 15' 177 ~q . ft. any No orange-red fall color 
Bowhall Maul~ Acer mbmm 'Bowhall' 40' 15' 177 sq. ft. any No bright red fa ll color 
Frans Fontaine 
~ f1ornbcam C01pim1S bet11111s 'Frans Fontaine' 35' 15' 177 sq. ft. any 0 narrowest of the Corpin11s b. cultivars 
·=1 
s., Dawvck Purple Beech Fog11s rylvotico 'Dawyck Purple' 40' 12' 113 sq. ft. any No purple leaves for entire growing season 
~ 
a.. Princeton Scnto• Cinkl?o Ginkgo bilobn 'Princeton Sentry' 40' 15' 177 sq. ft. any No seedless, bright yellow fall color 
c 
,\rnold Tulin Tree Liriodmdron tuljpifero 'Arnold' 40' 10' 79 sq. ft. No fast grower a- any 
" :;) 
~ Edith Bog~,IC Magnolia Magnolia grondifloro 'E dith Bogue' 30' 15' 177 sq. ft. any No broadleaf evergreen 
~ Galaxy Magnolia Magnolia x 'Galaxy' 30' 15' 177 s . ft. any No showy pink flowers 
n 
8.. Tschonoskii Crabapnlc Malus tschonoskii 30' 15' 177 sq. ft. any No good fall color 
" ;;:l Arnold S~ntincl Austrian 
~ Pine Pim1s nigra 'Arnold Sentinel' 35' 10' 79 sq. ft. No evergreen conifer •J. any 
0 
Fastiltiatc White Pine Pinus strobus 'Fas tigiata' 30' 10' 79 sq. ft. well drained evergreen coni fer ~ 0 
..- Quaking ,\ sucn Pop11!11s tmmdoides 30' 15' 177 sq. ft. any 0 native to the Portlan~ Metro region 
0-
c Capital Pear Py ms cnllerymm 'Capital' 35' 12' 113 sq. ft. any No glossy summer foliage 
3 
" C:hanti~;l~~r P~ar Pyms colleryona 'Chanticleer' 40' 15' 177 sq. ft. any No resistant to ftreblight 
--:: 
-..J C:olumnl!r ~l!rgent Ch~rQ' Pmn11s sorgmtii 'Columnaris' 35' 15' 177 sq. ft. pink flowers and reddish bark 
"' 
any 0 
Skyrocket Oak Q 11erms robor 'Fastigiata' 45' 15' 177 sq. ft. well drained No may hold brown leaves into winter 
Querc11s robur :x:Q . olbo 
Crimson ~nirc Qak 'Crimschmidt' 45' 15' 177 sq. ft. well drained No red fall color 
C iant . \ rborvitac evergreen conifer, species native to the 
"\'ircsccns" TIJJ!}o plimlo 'Virescens' 25' 12' 113 sq. ft. moist 0 Portland Metro Region 
Corinthian Linden Tilio cordata 'Corzam' 45' 15' 177 sq. ft. any 0 narrowest of the linden cultivars 
Columnar Z~lkova Zelkovo sen-oto 'Musashino" 45' 15' 177 sq. ft. any No fmc textured leaves 
Page 1 o f 1 

Appendix 5 
Native Trees 
Grand Fir Abies grandis 150' 40' 1256 sq. ft. Large Wetland, Riparian, Upland 
Bi~-l~a f MaRl~ A,·er macropl!fi!JJm 65' 50' 1963 sq. ft. Large No Upland 
Red Alder Aln11s mbra 100' 40' 1256 sq. ft. Large No Riparian, Upland 
n Madronc Arbl!llls mem:jesii 40' 30' 707 Stl_: ft. Medium No Upland 
~ -
Pacific DoJ,lWOOd Conms 11/tltn//ii 40' 30' 707 sq. ft. Medium No Upland 0 
~ 
d'i. 
Black llawthorn Cmtmg11s dot~~lnsii 25' 20' 314 sq. ft. Small Yes Wetland, Riparian, Upland 
" Ore~on ,\sh F raxinm latifolia 60' 30' 707 sq. ft. Large No Wetland, Riparian 2.. 
c Ponderosa Pine Piti/IS ponderosa 200' 30' 707 sq. ft. Large No Upland g-
::l 
6- Black Cottonwood Pop11l11s balsamifera ssp. tricbocarpa 175' 40' 1256 sq. ft. Large No Wetland, Riparian a 
~ ( )uakin~ .\~Rs:n Pop11l11s lrenmloides 30' 15' 177 sq. ft. Medium No Wetland, Riparian 
~ Bitter Cherry Pmtuts ema'l)nala 30' 20' 314 sq. ft. Medium No Riparian, Upland b' 
n. 
" Dou~las Fir Psettdotmgn mem(jesii 180' 40' 1256 sq. ft. Large No Upland 
"' 
" Ore~on White Oak Querms gnrrynnn 65' 50' 1963 sq. ft. Large No Upland -: :;; 
5 Cascara Rhatmms p11rshimw 35' 25 ' 491 sq. ft. Medium No Riparian, Upland ~ 
Pa!;ific Willow Salix Iucida ssp. lasiandra 40' 30' 707 sq. ft. Medium 0 Wetland, Riparian 
< 0 Rigid Willow Salix tigida var. macrogemma 30' 20' 314 sq. ft. Small No Wetland, Riparian c 
3 Scoulcr Willow S ali:x sco11leriana 40' 40' 1256 sq. ft. Medium No Wetland, Riparian, Upland 
" 
< Pacific Yew Tax us brevifolia 40' 30' 707 sq. ft. Medium No Riparian, Upland 
_, Western Red Cedar Tlmjn plica/a 
"' 
100' 30' 707 sq. ft. Large No Wetland, Riparian, Upland 
Western I I em lock Tsuga beteropi!JIIa 150' 40' 1256 sq. ft. Large No Riparian, Upland 

< 0 §' 
" 
~~ 
Norway maple 
Sycamore maple 
Tree-of-heaven 
Eur&ean white birch 
English hawthorn 
English holly 
Princess tree 
\Xlhite £8l?.lar 
Sweet cherry 
Black locust 
-European mountain ash 
Siberian elm 
Appendix 6 
Nuisance Tree List 
1~lil'i'rnl L., • 
Acer platanoides 
-
leaf detail 
Am·pseudoplatanus leaf detail 
-Ailanthus altissima leaf detail 
Betula pendtda leaf detail 
-Crataegus monogyna leaf detail 
Ilex aquifolium leaf detail 
Paulownia tomentosa leaf detail 
Populus alba leaf detail 
Pnmus avium leaf detail 
Robinia pseudoacacia leaf detail 
-S orbus aucuparia leaf detail 
Ulmus pumila leaf detail 
L, • lltiluu~~ 
-fruit detail flower detail 
fruit detail flower detail 
-fruit detail flower detail 
fruit detail flower detail 
-fruit detail flower detail 
fruit detail flower detail 
-
fruit detail flower detail 
fruit detail flower detail 
fruit detail flower detail 
-fruit detail flower detail 
fruit detail flower detail 
fruit detail flower detail 

[REVISIONS: 
\ 
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I 
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10' SETBACK 
1~ 
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1. AU. l'a!TIONS or LDTS 1 ANO 2 NOT OCCUPED BY WI.DINGS Oil PA~NG TO I£ 1-"«JSCN'E AHO IRRIGATED. 
2. AU. NQHIITM: >rGUAOON llllliiN 1liE 50' STREAH Bl1fflR IH 110CT A TO I£ RDI<MD Nil REPI.ICED Wl1li KIJ1\'E 
>rGUAOON AHO TEII'QW!Y RRIC.IOON fOil A PERIOO or ONE ruR Oil lJI1l. PlAHT'l ARE EST-'IUHD. 
ROOT PRO!£COON ZONE N0TIS: 
ENCRO!CHIDT INTO THE ROOT PROTECTION ZOI£ IS AU.OWED Willi PROJECT AR80RIST APPflfNAL ~ OE5CRIID IN 11£ 
fW.OW1NG NOTES' 
1. EXCAVAOON IN 11£ Ttl' 24" or THE SOIL IN TliE CRIOCAl ROOT ZONE AREA SHCUlD I£GIH AT 11£ EXCAVATION UNE TliAT 
IS Q.OS[5f TO 11£ 1RIL 
2. THE EXCAVAOON SHCUlD BE 001£ BY HANO/SH<Ml. Oil Willi A IIICKHOE ANO A WAH Wl1li A 5001!1. PRUNING SI£IRS, 
AHO A PRUNING SAW. 
J. F 001£ BY HAN!, AU. ROOIS 1" Oil lAAaR SHCUlD BY PRUNEO AT THE EXCAVATION LINE. 
4. F OONE Willi A IIICKHOE (WOST UKD.Y sctNIRIO), THEN 11£ (PER.ITIJil SIWJ. STIRf 11£ CUT AT 11£ EXCAVATION lJ£ 
AHO CNULUY "FED." FUR ROOTS/RESISTAHOC WHEN THERE IS RESISTAHCt THE WAH Willi THE SH<Ml. HAN! ~ 
AROUHO 11£ ROOTS ANO PRlNES 1liE ROOIS lAAaR 1HAH 1" OIAIIETER. 
TREE PROTECTION NOTES: }__ j or \~ "I A. NO CHANG£5 SIWJ. 1£ ljAjJ[ TO IHY ASPECT or TliE N'f>R(Ml) l.I!IWj FOOES1RY P1H1 WITHOOT WR1TID1 COOS£NT fROW 11£ PROJECT NlllOOIST ANO art NlllOOIST. 
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PROTECTION WU 1£ NSTAUID PRIM TO IHY GROUNJ OISTliRilANCE WORK, Q!NlH;, ANO CRAOING WU FOllOW. 
C. PVoCIHG WAT'ERW.S NENl THEES. NO P£RS(Jj WAY CIJfOJCT NfY IC1MTY WITlfH 11£ PROTECTID M9. or NfY TR!I DE51GHATED TO RDIAIH, IQ.UOING, 001' NOT UIITED TO, PAAIONG 
EQUAIENT, PVoCIHG SOLI'EJIIS, STOiliNG IIUlJ)H; WATER\11. ANO SOL OEPOSIT5, OOIIPIIG CONCm£ WASHOUT ANO LOCATN: !lJRN H<US. 
TAX LOT 600 
TAX MAP 2'; I 04BD 
-; __ ,.J 
-..----+ 
I, JOHN ARBORIST, AffiST THAT 
THIS TREE CANOPY SITE PlAN 
MEETS All OF THE 
REQUIREMENTS IN SECTION 10, 
PART 2, OF THE CITY OF TIGARD 
URBAN FORESTRY f.IANUi\1.. 
JOHN ARBORI$1, CERTIFIED ARSORI$1 
PNN-0000 
- t 
( 
TAl LOT 800 
l,l TAX V.AP 2) I 04BD 
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TAX MAP 25 I 04BD 
ANO«:RPOMHllDII: 
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t PROTECll'IE BARRIER. PRIOil TO NfY GROIN) IJSM!IOHCE BY 11iE COifTR.OCTOit 
I. SIWJ. EREl:T ANO WAIITAI< R£111Y '<!SIIIl£ TR!I PROTECTION FENCING ALONG 11iE OOTER EDGE ANO tafliTEI.Y SIRlWOHC 1liE PROTECTID M9. or AU. PROTECTED 1HEES Oil 
CROUPS or 1HEES ~ SllOWN. I1HCES SIWJ. 1£ COHSTRIJC1ID or 5 FOOT TAU. IET.Il. SEllJRED TO EJQfT FOOT TAU. WETAL P0m. POSIS SIWJ. NOT 1£ PI.ICED FURTHER 1HAH 
8 FEU O.C. if'IRf. 
2. WAY 1£ REQUIRED TO COYER Willi 11\11.0< TO A OEl'TH or AT lfAST SIX (6) INCHES, Oil WITH Pl'IWOOO Oil SMtAA WATERW.. <MR 1li( ROOT ZONE or A TR!I IN OllOER TO 
PROTECT ROOTS fROW llAWAGE CAUSED BY HEAVY EQUAIENT. 
J. SIWJ. I'RaliiiT EXCAVATION Oil COWPN:TING or fN!TH Oil 01lfR POTEiffiAU.Y IWUGHG .ICTMTE5 wmtH 11iE TREr PROTECTION ZONt 
4. WAY 1£ REQUIRED TO WNWIZE ROOT OAWia BY EXCAVATION or A TWO (2) FEU OEEP 1REIIQi, AT 11iE EilGE or 11£ TR!I PROTECTION ZONt TO ClfANLY S&Ul TliE ROOTS or 
1HEES TO 1£ RETAHD. 
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WAIITAI< 1HEES 1IIROUCHOUT CONSTRUC110N PERIOO BY WAn:RING ANO FERTUZING. 
6. SIWJ. IIAINT.IIH 1liE TREr PROTECTION FIIICit«: IH P1XE lMl. 11iE PROJECT NlllOOIST ANO art NlllOOIST IIITI«RZES 1l£R REWIAL 
7. SIWJ. El6R' T111T 1HY I.NfS:APt(; OOHE IN 11iE TREr PROTECTION ZOI£ SUBSECUENT TO 11£ REIIOYAL or 11£ BARRIERS SHAll 1£ ACCal'lJSHID lll1li lJQ([ IIIOIHERY Oil 
HAN! LABOR. USE PLANT WAT'ERW.S WITH CIIUPATI!l£ WATER REiliHIENT'l TO TREr TO 1£ PRESUMD AHO IHCT SPRAY IRRIGATION AWAY fROW TRUNKS. 
f. 11£ GRADE SIWJ. NOT 1£ EllVATED Oil REIIUC(D WITHfj 11£ TR!I PROTECTION ZOI£ WIIHOUT 11£ PROJECT AR90iliST'S .IIJ1IiORIZAllO. 11£ PROJECT AR80RIST WAY AU.OW CfMIIJI:£. 
or UP TO 01£ HAlf or 11£ M9. or 11£ TREE'S ROOT ZONE Wl1li lJQ([ sm5 (NO CLAY) TO 11£ - OEl'TH NEClSSIRY TO CARRY CUT CR.IIJNG Oil I.NfS:APt(; PLANS, F IT 
lW.l. NOT -_ 11£ SIJMI'Al or 11£ 1R1L AERATION OM:ES WAY 1£ REllliRED TO El6R' 11£ TREE's SIJMI'AL 
C. F 11£ GRADE .lllJ,IC()If TO A PRESUMD TR!I IS RAISal SlJCH TliAT IT <XlUUl Sl.lJUQI Oil ERm: INTO 11£ TR!I PROTECTIOH ZOI£, rr SIIIU. 1£ PERWANENTLY STAIIU2EO TO 
PRE'IENT SUITOCAOOH or 11£ ROOTS. 
H. AH lf'£JMOUS so.e'la: SIIIU. NOT 1£ INST.IU£D WITlfH 1liE TR!I PROTECTION ZOI£ or NfY 1REI: TO 1£ PRESUMD WITHOOT 11£ NJTIIORIZATION or 11£ PROJECT NlllOOIST. 11£ 
PROJECT NlllOOIST WAY REQlH SPEllf1C CONSTRUC110N IETHOOS ANO/Oil USE or AERATION OM:ES TO El6R' 11£ TREE'S SUIMVAL ANO TO WINIIZ£ 11£ P0T00111. FUR ROOT 
tO.Wl llAWAGE TO 11£ IWPEIMOUS so.e'ACE. 
TO 1liE GREATEST EXTENT PR.IC1ICAl. liTIJTY TRENCHES SIWJ. 1£ LOCATED CUTSilE or 11£ TR!I PROTECTION ZOI£ or 1HEES TO 1£ PR&RV£0. 11iE PROJECT AR80RIST WAY RECUR: 
TliAT U1lJT(5 BE TUHNEliil lHlER TliE ROOIS or TR!IS TO BE PRESUMD F 11£ PROJECT AR80RIST ~ TliAT TREHCIING WOULD SICHifK:AHTLY REilUC[ 11£ OW«:ES or 
THE 1HEES SlfMiAL 
J. om:T'OW. ffi!JHC. IIIRECTIONAL FWJ<G or 1HEES SIWJ. BE USID TO AVOO OAWAGE TO TRErS DE51GHATED FUR PI!&RVAOON. 
K. ~ REWRDIEHTS. THE PROJECT AR80RIST WAY REQUIRE ~ TREr PRESEJNAOON WfASlH5 MtCH ARE CONISISTEHT Willi TR!I CARE INIJUSIT!Y STAHOAROS. 
SCALE ! " = 20 FEET 
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SCALE SHOWN IS FOR FULL 
SIZE SHEET ( 24"X361 ONLY 
lEOEN) 
EXISrt«: TR!I TO BE RDI<MD 
EXISrt«: TREr ORI'IJIE 
ElQSTIHC TR!I CNWr M9. 
CNWr M9. 
TREr PROTECTION I1HC£ 
EXISTt«: SNITARY 
PROPOSID SNITARY 
EXISrt«: WATER 
PROPOSID WATER 
PROPOSID WATER 1ETER 
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""'"""POStS. 5. OC«:E SKUDII: IIN«MMED ltiROUQDJI'COICSIRl.CTIOfl 
METAL TFEE PROTECTION FENCE 
TREE PRESERVATION/REIIDVAL PlAN BY JOHN ARBORIST, 
CERTIFIED ARSORIST #PN-0000, WITH I>BC COllABORATIVE. 
EXIST1NG STMW 
PROPOSID STOilW 
EXIST1HC 00 
PROPOSID 00 
EXISTING El.EC!RIC 
PROPOSID El.ECTRIC 
PROPOSID IRRKliOON 
N'PROXIWATE STREAH BED LOCATION 
WETIJH) 
SICHFIC.IHT HAIITAT BOUNliRY 
~ 
r-:-:l 
1:.........:... 
EXAMPLE TREE 
PRESERVATION AND 
REMOVAL SITE PLAN 
EVERGREEN HEIGHTS PARTITION 
190 SW 147TH ST. 
:'::<;,~·~;;~:~' 1 ;1 1TE 1 ~ABc ~omml!!! .. !m.!:.!l·- - .....!:!!:L._ __ -.~:7= : ~ ~1~':~,~:,~:;2' PREPARED FOR: :'ooi'"1~ 
FA'( : (503} !i:l5-'('('(X 11CARO ~<X'N 97223 I TIGARD 
'""' 1woo'"' -o" , .. ,.., ,. '"" COLLABORATIVE Pit s00-909-5555 OREGON 
""i I JOO NUMBER 2001 I SHEET 
APPENDIX 7 x::_o~ l l("f\Sf.ll I 'I t.JR. W,\, 1 Ill .-... ~t 'if'Ht " ~ . 1111 "tnct .w • I'll "-' ''«- • t I.,.N V· \ ;j{ H nn '"" FAX: 503_909-5556 TAXLOT 1700 TAXIIAP 2 4E 25 
City of Til-,'<trd Urban l'o rc>try Co de Rc\' i>io m I Vo lume I\' I 79 
!REVISIONS: 
\ 
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IWITAT IDHW!Y I 
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EXAMPLE 
TREE CANOPY 
SITE PLAN 
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TAX LOT 600 
fAX MAP 2S I 0480 
()t-} l fl:. l iK'.\ rtiJ ,\1': ~~ 
IOOOISTSTREt:T. Sl iTE I /A. ~B ,.._cr-.,.......~-~~ TI GARIJ, OREGON 97l2:1 
Ptl : (:lO.U 555-H'('( 
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001 
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KRJ 
·•B'f': IIH 
~8'1': KRJ 
PREPARED FOR: 
fAX lOT 700 
TAX MAP 2S I :)480 
.of< Sill~ 
PO BOX 111 
9A 
AS SHOWN 
llGNil, ~GQI 9722J 
Pit SOJ-909-5555 
FAX: SOJ- 909- 5556 
City or Tigard Urban l'orcstry Code Rnisions I \'olumc I\' I il l 
PLANT LEGEND 
srnEET TFEES 
SYI8l. OllES. BOTAHICAI. IWIE COIIIIOHtw.£ 
0 
0 
NOre 
JaR RUIJ!UW 'ARIISTR()f«;' ARIIS1ROHC RED loiiPl.E 
IIIQQJA GRAHOFlOO 'EmH 80CUE' Elli1H 90Gl.{ IIIQQJA 
SIZE COIOTlOH SPACH; 
2" COL Bas AS SHOWN 
2" COL Bas AS SHOWN 
1. PlNmR S1R1P AREAS II.IH; r.tRGRfiH tNt' Nfl SW 147m N!! AREAS CF POTOO\Il SOL COlli'~. U1111NG TREE CROWIH. IF SOL COIF~ 
OCOJRS, IIAC1<HOE TURNING SIOO.D BE USED TO LOOSEN SOIL 
2. IIAC1<HOE TURNNG' REIIOYE NfY IA'IERS CF GOOD TOPSOIL SPR00 J"- 4" CF ORGIH1CS (HGIH.XMN COI1POST) CR E5CS (EXPAHDED SHALE/CALCI£ 
aAY) AWENOWENT <MR Ill( M1fA PRIOR TO TURNNG M S01L IIIMANHC A SAFE IXSTAHC£ fROII PAVH;, SIOCWAU<S, Nfl STRUCTURES, USE IIAC1<HOE 
TO TURN Sll1l TO l6" OEPlH. BR£N< SOIL NTO l.ARGI: PEDS Nfl lOOSElY r«:CRPCRAI£ M SOIL AIIE>«JWWO. WIIHfAfj A Sl.llPE CF COII'N;IDJ SOIL AT 
M EDGE CF CF PAVING SO AS NOT TO UNO£Rij1NE ~E PAVING SU9-BASL 1W«> TURNNG WAY BE 1£CESSIR'f AL<H> M EDCES CF PAVING AHO AT 
WALLS, DO NOT Ill TO A DEP1H CR£A11R ~ mE BOTTOW CF F0011NG. AFTER tuRNNG, R!' -SPROO RFSOl. AHD .000 l" -5" CF YARO WASil: CRGINC 
AW£l«))j£HT <MR Ill( SURF.-cE Nfl UG!ffi.Y Ill TO BR£N< mE SOIL INTO TEXTURE SOOAil£ TO fH: CR.IOC 
SCALE ! " = 20 FEET 
---
~· .!"'!. ~ ~ 
SCALE SHOWN IS FOR FUU 
SIZE SHEET ( 24.X36") ONLY 
LEGEM? 
EXIST1NG TREE DRI'IK 
PLAHTED TREE WAI\.RE ORI'IJE 
EJC1S11NG TREE CAHOPY AR!'A 
CAHOPI' AR!'A 
TREE PR01£C110N fENC[ 
EXISTING SMTIRI 
PRa'OSED SMTIRI 
EXIST1NG WAT!R 
PRa'OSED WAIIR 
PRa'OSED WAIIR WE11R 
EX1S11NG WAT!R WE11R 
EXIST1NGSTORII 
PRa'OSED STCRW 
EJC1S11NG GAS 
PRa'OSED GAS 
EXIST1NG El£t1R1C 
PRa'OSED ELECTRIC 
PRa'OSED IRRIGATION 
N'I'RQ)IIIAI£ S1R£AW BED LOCATION 
W£1\N() 
S1GIWI:AHT IWITAT BOUNIW!I' 
~ 
CZl 
CJ 
I 
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L.....::....J 
I, JOHN ARBORIST, AffiST THAT 
THIS TREE CANOPY SrTE PLAN 
~EETS All OF THE 
REQUIREMENlS IN SECTION 10, 
PART 2, OF THE CITY OF TIGARD 
URBAN FORESTRY MANUAL 
ED ARBORIST JOHN ARBORIST, CERTIFI PNN-0000 
DAlE: 07-11-2011 
EVERGREEN HEIGHTS PARTITION 
190 SW 147TH ST. I JOO NUMBER TIGARD OREGON 
TAXLOT 1100 TAXWAP 2 4E 25 
-- -
2001 
SHEET 
APPENDIX 8 
Urban Forestry Plan -Supplemental Report Example Template 
General Information 
Date: 
Project Name: 
Project Arborist or Landscape Architect Name: 
Project Arborist or Landscape Architect Address: 
Project Arborist or Landscape Architect Telephone Number: 
Project Arborist or Landscape Architect Email Address: 
ISA Certi fied Arborist No.: 
Landscape Architect Stamp: 
Project Summary 
Specifications 
Tree Protection Fencing Specifications: 
Tree Preservation Specifications: 
Stand Preservation Specifications: 
Soil Characteristics and Specifications for Improvement: 
Tree Planting Specifications: 
Stand Planting Specifications: 
Appendix 9 
City of Tigard Urban Forestry Code Re,·isions I Volume IV I 83 
~ :::r 
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2 . .  
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3 -
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E x i s t i n g  T r e e  I n v e n t o r y  
G e n u s  s p . /  
C o m m o n  
E x i s t i n g  S t a n d  I n v e n t o r y  
S t a n d #  
G e n u s  s p . /  
C o m m o n  o f  D o m i n a n t  
G e n u s  s p . /  
C o m m o n  o f  z n d  
G e n u s  s p . /  
C o m m o n  o f  3 r d  
U r b a n  F o r e s t r y  P l a n  - S u p p l e m e n t a l  R e p o r t  E x a m p l e  T e m p l a t e  
O p e n  o r  
C o m m e n t s  
S t a n d  G r o w n  
A v g .  D B H  1  A v g .  C o n d .  O v e r a l l  S t a n d  T o t a l  
C a n o p y  
C o m m e n t s  
R a t i n g  1  P r e s .  R a t i n g  C a n o p y  P r e s e r v e d  
A v g .  D B H 2  A v g .  C o n d .  
( f t 2 )  ( f t 2 )  
R a t i n g  2  
A v g .  D B H 3  A v g .  C o n d .  
R a t i n g  3  
Urban Forestry Plan -Supplemental Report Example Template 
Planted Tree Inventory 
Tree# Genus sp./ Caliper (Decid.) or Mature Canopy Mature Canopy Available Comments 
Common Height (Evergreen) Spread (ft) Area (ft2) Soil Volume (ft3) 
Planted Stand Inventory 
Stand# Genus sp./Common 1 Hgt. or Container size No. ofTrees Avg. Spacing (ft) Total Mature Comments 
Genus sp./Common 2 Hgt. or Container size No. ofTrees Avg. Spacing (ft) Canopy Area ( ft2) 
Genus sp./Common 3 Hgt. or Container size No. ofTrees Avg. Spacing (ft) Delineated at the 
Genus sp./Common 4 Hgt. or Container size No. ofTrees Avg. Spacing (ft) Outer Edge of 
Genus sp./Common 5 Hgt. or Container size No. ofTrees Avg. Spacing (ft) the Stand 
· : : : : '  
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U r b a n  F o r e s t r y  P l a n  - S u p p l e m e n t a l  R e p o r t  E x a m p l e  T e m p l a t e  
E f f e c t i v e  T r e e  C a n o p y  C o v e r  S u m m a r y  
* L o t  o r  L o t  o r  T r a c t  2 x  C a n o p y  2 x  C a n o p y  1 . 2 5 x  M a t u r e  
M a t u r e  1 . 2 5 x  M a t u r e  T o t a l  C a n o p y  E f f e c t i v e %  
T r a c t #  
A r e a  ( f t 2)  A r e a  ( f t 2)  o f  A r e a  ( f t 2)  o f  
C a n o p y  C a n o p y  C a n o p y  
A r e a  ( f t 2)  p e r  
C a n o p y  
( e x c l u d e  
P r e s e r v e d  
P r e s e r v e d  
A r e a  ( f t 2 )  o f  A r e a  ( f t 2)  o f  
A r e a  ( f t
2
)  o f  l o t  o r  t r a c t  
( C a n o p y  A r e a  
s t r e e t s )  
T r e e s  S t a n d s  N a t i v e  N o n - N a t i v e  P l a n t e d  
( w  /  c o n d .  a n d  ( w  /  c o n d .  a n d  
P l a n t e d  P l a n t e d  S t a n d s  
L o t  o r  T r a c t  
pres . ~2) pres . ~2) 
T r e e s  T r e e s  
A r e a )  
T o t a l  
* N o t e :  e f f e c t i v e  t r e e  c a n o p y  c o v e r  i s  r e q u i r e d  t o  b e  c a l c u l a t e d  o n  a  l o t / t r a c t  b y  l o t / t r a c t  b a s i s  o n l y  i n  t h e  R - 1 ,  R - 2 ,  R - 3 . 5 ,  R - 4 . 5  a n d  R - 7  d t s t r t c t s  .  
T h e  s t a n d a r d  p e r c e n t a g e  o f  e f f e c t i v e  t r e e  c a n o p y  c o v e r  f o r  e a c h  l o t  o r  t r a c t  i n  t h e  R - 1 ,  R - 2 ,  R - 3 . 5 ,  R - 4 . 5  a n d  R - 7  d i s t r i c t s  s h a l l  b e  a t  l e a s t  
1 5  p e r c e n t .  
T h e  s t a n d a r d  p e r c e n t a g e  o f  e f f e c t i v e  t r e e  c a n o p y  c o v e r  f o r  t h e  o v e r a l l  d e v e l o p m e n t  s i t e  s h a l l  b e  a t  l e a s t :  
1 .  4 0 %  f o r  R - 1 ,  R - 2 ,  R - 3 . 5 ,  R - 4 . 5  a n d  R - 7 d i s t r i c t s ,  e x c e p t  f o r  s c h o o l s  ( 1 8 . 1 3 0 . 0 5 0 0 ) ) ;  
u .  3 3 %  f o r  R - 1 2 ,  R - 2 5 ,  R - 4 0 ,  C - N ,  C - C ,  C - G ,  C - P ,  M U E ,  M U E - 1 ,  M U E - 2 ,  M U C ,  M U R  a n d  I - P  d i s t r i c t s ,  e x c e p t  f o r  s c h o o l s  
( 1 8 . 1 3 0 . 0 5 0 0 ) ) ;  a n d  
w .  2 5 %  f o r  M U - C B D ,  M U C - 1 ,  I - L  a n d  I - H  d i s t r i c t s ,  a n d  f o r  s c h o o l s  ( 1 8 . 1 3 0 . 0 5 0 0 ) )  i n  a l l  d i s t r i c t s .  
Urban Forestry Plan - Supplemental Report Example Template 
Tree Canopy Fee Calculation (if applicable) 
If the percentage of effective tree canopy cover is less than the applicable standard percentage for 
the overall development: 
1. Find the required ft2 of tree canopy: 
(overall development site area) x (standard required % (40%, 33%, or 25%)) . 
2. Find the ft2 of tree canopy the development is short: 
(required ft2 of tree canopy from 1 above) - (proposed ft2 of tree canopy). 
3. Find the $ value of tree canopy: 
(PNW-ISA wholesale median cost for a 3" deciduous tree in the Willamette Valley) + 59. 
4. Find the required tree canopy fee: 
(amount of ft2 of tree canopy from 2 above) x (the $ value of tree canopy from 3 above). 
If the overall development meets the applicable standard percentage, but the percentage of effective 
tree canopy cover is less than 15% for any individual lot or tract in the R-1, R-2, R-3.5, R-4.5 and R-
7 districts: 
1. Find the required ft2 of tree canopy for the deficient lot or tract 
(lot or tract area) x 15%. 
2. Find the ft2 of tree canopy the lot or tract is short: 
(required ft2 of tree canopy from 1 above) - (proposed ft2 of tree canopy). 
3. Find the $ value of tree canopy: 
(PNW-ISA wholesale median cost for a 3" deciduous tree in the Willamette Valley) + 59. 
4. Find the required tree canopy fee: 
(amount of ft2 of tree canopy from 2 above) x (the $ value of tree canopy from 3 above). 
Signature of Approval 
I hereby attest that: 
1. The Tree Preservation and Removal site plan meets all of the requirements in Section 10, 
Part 1 of the Urban Forestry Manual; 
2. The Tree Canopy site plan meets all of the requirements in Section 10, Part 2 of the Urban 
Forestry Manual; and 
3. The Supplemental Report meets all of the requirements in Section 10, Part 3 of the Urban 
Forestry Manual. 
Appendix 9 
Ci1y of Tigard Urban Forestry Code RcYisions I \'o lumc IV I 87 

/ 
EVISIONS: 
y;; 
EXAMPLE TREE 
CANOPY SITE PLAN 
FOR SINGLE LOT 
I 
I 
i 
I 
I 
I 1 
~ i ~ 
15 : 
tt: l 
«> s 
EVERGREAN LANE r~ ~-=r-:-~ 
PLINT!R Sll!IP: NlfA CF POTEJITW. SOl 
r-:::rACTlON, SEr NOTES 1 t 2 11fS 
- ~ 
I 
I "--- r1:i FOR IRGAOOH 
I ,r/ LOT2 I 5,056 SF 
I 
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I 
PRa'OSED BWJNC F001PR1If1 
~¢ 
3 
8,173 SF ·"' t_'f...f:>\I~G 
; ...... " 
STREET TREES 
S'tiiOOl BOTNIICAL NAIIE CClUJH- S1l! CONOOlON SPACH: 
0 loCtR RUBR\111 'NlWSTRQHC' ARIIS1RONG RED WAPI£ 2" CAL Bt9 115SHOWN 
NOT[, 
1. PLINT!R STRI' AREAS .ILONC MRCREIN 1,\NE Al«l SW 1471H ARE AREAS CF P0TEJ1TW. SOl CCII'.ocnoN, lJITlHG TREE GROWIH. F SOl 
COIIPACTlON OCCUlS. III01HOE MNNG SHOW! BE USED TO L.OOSEH SOl. 
2. BIOOfOE MNNG: RDI11IE /oKf LAYERS CF COOO TlJ'SOIL SPR£.10 J" -4" CF ORGIHoCS (HIQHJCHIN CCII'OS1) OR ESCS {EXPNIOED 
SHAl£/C.ILCH: OAY) Noe<OIIOO !MR mE N1.EA. PIOOR TO nJRHN; mE SOC. IIAIITAHHC A SAFE IJSTAHCE fROII PAW«:, SIOEWAU<S, 
SCALE I" - 10 FEET 
---
[ ---.--J 
9 ° .... - 9 
SCALE SHOWN IS FOR FULL 
SIZE SHEET ( 2_..X361 ONLY 
NIO SlRUCl\RS, USE III01HOE TO nJRN SOL TO J6" DEPTH. BRL1K SOl. IHTO 1.1RC!: PEDS MJ l.OOSRY IHCORPOIWl: mE SOIL 
AWOOIIOO. IWHTAI< A SlOPE CF CCII'AC!Ul SOIL AT mE EDGE CF CF PAVING SO 115 NOT TO UNOERIIIIE mE PAVING SUB-BASE. HNIO 
nJRNING WAY BE NECESSN!Y li.ONG mE EDGES OF PAVING Al«l AT WAU.S, 00 NOT 111 TO A OEPTH. GREATtR mN1 mE BOTTOII OF 
FOOTIHG . .lfTIR 1\JRNNC, R£-SPR£.10 TUPSaL Al«llro J"-5" CF YARD WASTE ORCN«: AWENiliEifT !MR mE 9..1<FACE AND UGHTlY TU 
TO BRL1K mE SOl. IHTO 1UTURE SUTAil£ TO F1HE GRADE. 
L.EGEtj) 
EXISTI4G TREE ORf'UNE 
Pl,INTEO TREE WAIURE DRIPI.K 
EXlSTlHG TREE CANOPY NlfA 
CANOPY AREA 
TREE PROTEt110N FINCE 
EXISTI4G SINITARY 
PROPOSED SINITARY 
EXISTI4G WATtR 
PROPOSED WATtR 
PROPOSED WATtR WffiR 
EXISTI4G WATtR WETtR 
EXISTI4G STORW 
PROPOSED STORW 
EXISTI4G GAS 
PROPOSED GAS 
EXISTI4G EIICTRIC 
PROPOSED EIICTRIC 
PROPOSED mGAOOH 
SICNFICANT IWITAT IIOIHlORY 
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~'' <so» ss;-m x PFEPAAED fOR: 
FA'(; 150:J) :'i:l5-H'{'( ~sw1m PO BOX 111 
F\1\IL ; I ~F()jt-I.Hf_fOII -\HliRATI\'F..roA COLLABORATIVE TlGARD, DR£GON 9722J 
Pit 503-909-5555 
FAX 503-909-5556 
EVERGREEN HEIGHTS PARTITION 
190 SW 147TH ST. 
Un~st-:ll IS OR. l A, ' Ill TIGARD OREGON 
TAXI.OT 1700 TAXWAP 2 4E 15 
City of 'l'i~o"' rd Urban l'orcsrry Code Rc,·isions I Vo lume IV I B9 
OAT[, 07-11 -2011 
I 
~~ 
JOO NU~BER 
2001 
SHm 
APPENOIX 10 

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r ROOT BARRIER PER MANUFACTURER'S - ~l SPECIFICATIONS II 
OPEN SOIL 
r-~OLUME 
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TOTAL SOIL VOLUME CALCULATION FOR TREE 'A': 
OPEN SOIL VOLUME= 100' x 5' x 3' = 1,500 C.F. 
COVERED SOIL VOLUME= 0 C.F. 
TOTAL SOIL VOLUME= 1,500 C.F. 
1,500 CF IS GREATER THAN THE SOIL VOLUME REQUIRED BY A 
STREET TREE IN AN 18' RIGHT OF WAY (800 CF) THEREFORE THIS 
SOIL VOLUME MEETS CITY REQUIREMENTS. 
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1 .~~ I II J ~SIDEWALK 
1-------- 18' RIGHT OF WAY -----__Jt--1 
PROFILE 
TREE 'A' 
,.----OPEN SOIL VOLUME 
ROOT BARRIER PER MANUFACTURER'S 
SPECIFICATIONS 
COMPACTED SUBGRADE 
City of Tigard Urban l'orestry Code Revisions I Volume IV I 91 
EXAMPLE SOIL VOLUME 
CALCULATION - STREET TREE 
WITH OPEN SOIL 
NO SCALE 
DWG. NO. 
APPENDIX 11 
+ + + + + 
+ + + + t~URB + + + + + 
. + + + + 18'RIGHT OFWAY 
+ + + + 
+ + + + + 
+ + + + 
+ + + + If + + + + + 
+ + + + 
+ + + 
+ 
ROOT BARRIER PER 
) ... I II MANUFACTURER'S 
+ + + SPECIFI CATIONS 
DRIVE\f.'AY 
COVERED SOIL VOLUME 
UNDER SIDEWALK 
DRIVEWAY 
~ 
+ + + + + 
+ + + + 
+ + + + + 
+ + + + 
PLAN 
4' X 4' TREE CUTOUT 
(OPEN SOIL VOLUME) 
STREET 
TREE 'A' 
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TOTAL SOIL VOLUME CALCULATION FOR TREE 'A': 
OPEN SOIL VOLUME= 4' x 4' x 3' = 48 C.F. 
COVERED SOIL VOLUME= 28' x 10' x 3'- 48 C.F. = 792 C.F. 
TOTAL SOIL VOLUME= 840 C.F. 
840 C.F. IS GREATER THAN THE SOIL VOLUME REQUIRED BY A 
STREET TREE IN AN 18' RI GHT OF WAY (800 C. F.) THEREFORE THIS 
SOIL VOLUME MEETS CITY REQUIREMENTS. 
18' RIGHT OF WAY 
PROFILE 
TREE 'A' 
OPEN SOIL VOLUME 
4' X 4' TREE CUT OUT 
ROOT BARRIER PER 
MANUFACTURER'S SPECIFICATIONS 
COVERED SOIL VOLUME 
DRAINAGE 
COMPACTED SUBGRADE 
City of Tigard Urban l;urcsrry Code Rcvisiom I \ 'olumc IV I n 
EXAMPLE SOIL VOLUME 
CALCULATION - STREET TREE 
WITH COVERED SOIL 
NO SCALE 
DWG. NO. 
APPENDIX 11 
I 
I 
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\ 
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BUILDING 
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BUILDING 
\ 
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'\. 
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'\.. 
/ 
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LIMIT OF AVAILABLE 
SOIL (50' RADIUS) 
/ 
/ 
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'-.. 
'-.. 
~ 
OPEN SOIL VOLUME= (PLANTER STRIP AREA+ FRONT YARD AREA CONNECTED BY THE COVERED 
CONTINUOUS ROOT PATH) x SOIL DEPTH 
PLANTER STRIP AREA= 6 FEET X 22 FEET= 132 S. F. 
AREA CONNECTED BY CONTINUOUS ROOT PATH= 4,000 S.F. 
OPEN SOIL VOLUME= (132 S.F + 4000 S.F.) x 3'=12,396 C.F. 
COVERED SOIL VOLUME = (SIDEWALK WIDTH) x (SIDEWALK LENGTH) x (STRUCTURAL SOIL DEPTH) 
COVERED SOIL VOLUME= (6') x (3') x (3') =54 C.F. 
TOTAL SOIL VOLUME=OPEN SOIL VOLUME+ COVERED SOIL VOLUME = 12,396 C.F. +54 C.F.=12,450 C.F. 
12,450 C.F. IS GREATER THAN THE SOIL VOLUME REQUIRED BY A STREET 
TREE IN A 12' RIGHT OF WAY (500 C.F.) THEREFORE THIS SOIL VOLUME MEETS 
I I 
CITY REQUIREMENTS. \--·' 
1 / 1 ~ g 
--
PLAN 
y 
OPEN SOIL VOLUME 
P~ll I I TREE 'A' 
STREET 
ROOT BARRIER PER 
MANUFACTURER'S SPECIFICATIONS 
SOIL VOLUME UNAVAILABLE TO 
TREE 'A' WHERE NO COVERED 
SOIL VOLUME ROOT PATH 
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(OPEN SOIL VOLUME) 
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SIDEWALK 
I 
OPEN SOIL VOLUME 
ROOT BARRIER PER 
MANUFACTURER'S SPECIFICATIONS 
ROOT PATH COVERED SOIL VOLUME 
City of Tigard Urban Forestry Code Revi,ions [ Volume IV ['13 
COMPACTED SUBGRADE 
'-----12' RIGHT OF WAY 1 
PROFILE 
EXAMPLE SOIL VOLUME 
CALCULATION - STREET TREE 
WITH ROOT PATH 
NO SCALE 
DWG. NO. 
APPENDIX 11 
"
 
E 
~ ;... 
I 
I 
I 
I f........_ ~ ',, < ~ '- '..'M (PROPE111Y UNE) 
... - RIGHT OF '-....._ 
18' RIGHT OF WA! 
RED MAPLE (TYP) 
) 
SCALE I" - 20 FEET 
----
~ .!"'!. J'U 
SCALE SHOWN IS FOR FULL 
SIZE SHEET ( 24-X36j ONLY 
IREVISIONS: 
", 
"~ ~ " 
" 
" ~ 
BUILDING FOOTPRINT 
EXAMPLE SOIL 
VOLUME PLAN 
STREET TREE LEGEND 
S"t\IBOl QllE5. BOTAHIC.II. NAME COIIWON HAllE ~ZE 
®" .oaR ROORIJW RED IIAfi..E J" CAL 
STREET TREE TABLE 
TREE NU~BER SPECIES OPEN SOIL VOLUME 
(CJ.) 
001 RED ~LE 1,860 
002 RED ~LE 2,637 
003 RED ~LE 2,637 
004 RED ~LE 2,637 
005 RED ~LE 2,037 
006 RED ~LE 1,434 
007 RED ~LE 888 
008 RED ~LE 639 
009 RED ~LE 1,362 
0010 RED ~LE 2,427 
0011 RED ~LE_ L_ ___ l,81_8 
01'1-' I Ct. LOC.f i'W AT: 
1000 1ST S'fREf:i. SI ITE I 
TIGARO, OREGON 9722:\ ~ ABc COLLABORATIVF Pll : (so:n sss-uH F,\X: (.'iO:J) .1;}5-'U H Fll ~IL: I NF()II: U«'~COU .\IlORATIVF..CUM 
L ICE~St:ll IN l)lt WA, &: W 
C()HDIOOfj SP.OONG 
~ IS SHOWN ~ 
~ ~ 
OPEN SOIL VOLUME 
COVERED SOIL VOLUME 
COVERED SOIL VOLU~E TOTAL SOIL VOLU~E REQUIRED SOIL VOLUME 
(CF) (C.F.) FOR 18' RIGHT OF WAY 
NA 1,860 
NA 2.637 
NA 2.637 
NA 2.637 
507 2,544 
804 2,238 
1,628 2,516 
1.707 2,346 
1,173 2,535 
198 2,625 
NA 1,818 
REMOVAL, STORING, AND AMENDED SOILS FOR PlANTER 
AREAS: 
CONTRACTOR SHAll REMOVAL All DEBRIS FROM PLANTER 
AREAS AND EXCAVATE TO A DEPTH OF 36INCHES. SLOPE 
SIDES OF EXCAVATIONS AT 1:1 SLOPE OR SHORE EDGES TO 
PREVENT UNDERMINING OF VEHICLE LOAD AREAS AND TO 
PROVIDE A SLOPED PROFILE TRANSITION BETWEEN SOIL TYPES 
AND STRUCTURAL FILL DISPOSE OF DEBRIS AND SUBSOIL. 
STOCKPILE EXCAVATED TOPSOIL IN APPROVED AREA OFF SITE. 
EXISTING AND IMPORTED TOPSOIL AMENDMENTS SHALL BE 
DETERMINED BY THE LANDSCAPE ARCHITECT AND APPROVED 
BY THE CITY ARBORIST. SOIL MIXING SHALL BE DONE IN 
DESIGNATED AREAS OR IN THE SUPPUERS YARD. MIX 
AMENDMENTS WITH TOPSOIL WHEN SOIL IS IN A FRiABLE 
CONDITION ONLY; DAMP AND NOT MUDDY WITH ADEQUATE 
MOISTURE TO BREAK INTO CLODS WHEN TURNED AND WIU 
NOT LEAVE A MUD STAIN ON THE HAND WHEN SQUEEZED. 
CONTRACTOR TO PROVIDE CERTIFICATE OF CONTENT AND 
PERCENT OF SOIL MIXES WITH ALL AMENDED SOIL TO THE CITY 
PRIOR TO INSTALLATION. 
BLENDED SOIL PLACEMENT AND COMPACTION: 
SOIL SHALL BE FRIABLE WHEN PLACED AND COMPACTED. 
PLACE SOtl IN LAYERS OF NOT MORE THAN 1'Z' IN DEPTH. 
PROVIDE 3 PASSES Wlni A 'Z' COMPACT PLATE VIBRATING 
COMPACTOR. COMPACT TO 80-85% MAXIMUM DRY DENSITY AS 
MEASURED BY THE PROCTOR TEST OR AS APPROVED FOR 
SPECIFIC BLENDED SOIL MIXES. 
PREPARED FOR: 
(CF) 
800 
800 
800 
800 
800 
800 
800 
800 
800 
800 
800 
STREET TREE WITH COVERED SOIL DETAIL 
NOT TO SCALE 
STANDARD COVERED SOIL VOLUME SPECIFtcATIONS: 
PART 1. COVERED SOIL MATERIALS 
A. COVERED SOIL SHALL CONSIST OF THE FOLLOWING MIXTURE OF GRAVEL, SOIL AND ADMIXTURES: 
I. CRUSHED ROCK, GRADATION OF 100% PASSING 1.251NCH, MAX. 30% PASSING 0.751NCH; 
II. LOAM/ORGANIC TOPSOIL; 
Ill. SOIL BINDER SUCH AS , STABILIZER. ; AND 
rv. WATER 
PART 2. PROPORTIONS OF COVERED SOIL MATERIALS 
A. THE PROPORTIONS OF COVERED SOIL MATERIALS SHALL BE AS FOLLOWS: 
AMOUNT FOR 1 CY AMOUNT FOR 4.6 CY 
MATERIAL OF COVERED SOIL OF COVERED SOIL 
CRUSHED ROCK 23.2 CUBIC FEET 4 CUBIC YAROS 
TOPSOIL 5.9CUBIC FEET 1 CUBIC YARD 
SOIL BINDER 13.70Z 4LBS 
WATER 1.6GALLON 46GALLONS 
B. THE TARGET MOISTURE CONTENT IS 20% BY WEIGHT OF THE TOPSOIL WEIGHT. THE ABOVE WATER CONTENTS ASSUME THE TOP IS DRY. THE AMOUNT 
OF WATER THAT WILL NEED TO BE ADDED WILL BE DEPENDENT ON THE MOISTURE CONTENT OF THE RAW MATERIALS. ACTUAL AMOUNTS OF WATER 
USED SHALL BE DETERMINED DURING MIXING. 
PART 3. COVERED SOIL MIXING PROCEDURES 
A. MIX COVERED SOIL IN BATCHES OF AN APPROPRIATE SIZE FOR THE EQUIPMENT BEING USED. THE END RESULT IS TO BE AMATERlAL THAT IS 
UNIFORMLY BLENDED TOGETHER DO NOT BATCH IN QUANTITIES THAT WILL NOT ALLOW THE EQUIPMENT TO COMPLETELY MIX THE MATERIAL. 
DETERMINE BATCH SIZE AND QUANTITIES OF EACH MATERIAL NEEDED FOR THE BATCH. 
B. START WITH HALF OF THE CRUSHED ROCK MATERIAL. 
C. ADD All OF THE TOPSOIL MA TERlAL 
D. ADD THE SOIL BINDER 
E. ADD HALF OF THE ESTIMATED WATER 
F. ADO THE OTHER HALF OF THE CRUSHED ROCK MATERIAL. 
G. MIX THE MATERIAL TOGETHER. 
H. SLOWLY ADO WATER TO THE MIXTURE AND CONTINUE TO MIX. THE FINAL AMOUNT OF WATER WIU VARY WITH MOISTURE CONTENT OF THE CRUSHED 
ROCK AND TOPSOIL ADO WATER IN INCREMENTAL AMOUNTS AND MIX THE MATERlAL BETWEEN THE ADDITIONS OF WATER 
I. STOP ADotNG WATER AND MIXING WHEN THERE IS A MINUTE AMOUNT OF FREE TOPSOIL REMAINING. THE TOPSOIL WILL COAT THE CRUSHED ROCK 
AND NOT FALL OUT OF THE MATERIAL. All OF THE CRUSHED ROCK SHALL BE UNIFORMLY COATED WITH TOPSOIL THERE SHAll BE NO CLUMPS OF 
TOPSOIL OR UNCOVERED CRUSHED ROCK IN THE MIXTURE. 
J. IF TOO MUCH WATER IS ADDEO TO THE MIXTURE. WATER WILL DRAIN OUT OF THE MATERIAL AND THE TOPSOIL WILL WASH OFF OF THE CRUSHED ROCK. 
IF THIS OCCURS THE BATCH OF MATERIAL SHALL BE DISCARDED AND SHALL NOT BE INCORPORATED INTO THE COMPLETED WORK. 
PART 4. PLACEMENT OF COVERED SOIL 
A. PROTECT SOILS AND MIXES FROM ABSORBING EXCESS WATER AND FROM EROStoN AT All TIMES. DO NOT STORE MATERIALS UNPROTECTED FROM 
RAINFALL EVENTS. DO NOT ALLOW EXCESS WATER TO ENTER SITE PRIOR TO COMPACTION. IF WATER IS INTRODUCED ~TO THE MATERIAL AFTER 
GRADING, ALLOW MATERIAL TO DRAIN OR AERATE TO OPTIMUM COMPACTION MOISTURE CONTENT. 
B. All AREAS TO RECEIVE COVERED SOIL MIXTURE SHALL BE INSPECTED BY THE PROJECT LANDSCAPE ARCHITECT AND/OR PROJECT ENGINEER BEFORE 
STARTING PLACEMENT OF MIXTURE. All DEFECTS SUCH AS INCORRECT GRADING, COMPACTION AND INADEQUATE DRAINAGE, ETC •• SHALL BE 
CORRECTED PRIOR TO BEGINNING PLACEMENT OF COVERED SOIL. 
C. CONFIRM THAT THE SUB-GRADE IS AT THE PROPER ELEVATION AND COMPACTED AS REQUIRED. SUB-GRADE ELEVATIONS SHALL SLOPE PARALLEL TO 
THE FINISHED GRADE. CLEAR THE EXCAVATION OF ALL CONSTRUCTION DEBRIS. TRASH , RUBBLE AND FOREIGN MATERIAL. FlU ANY OVER EXCAVATION 
WITH APPROVED FILL AND COMPACT TO THE REQUIRED SUB-GRADE COMPACTION. 
0. INSTALL COVERED SOIL IN ~INCH LIFTS AND SPREAD UNIFORMLY OVER THE AREA. COMPACT EACH LIFT TO THE REQUIRED PERCENT OF MAXIMUM 
DENSITY. OELA Y PLACEMENT 24 HOURS IF MOISTURE CONTENT EXCEEDS MAXIMUM ALLOWABLE , PROTECT COVERED SOIL WITH PLASTIC OR Pl YWOOO 
DURING DELAY. TAKE PARTICULAR CARE NOT TO DAMAGE UTILITIES WHEN INSTALLING COVERED SOIL. COVERED SOIL THAT WILL BE THE BEDDING 
FOR UTIUTY LINES SHALL BE COMPACTED TO CONFORM TO THE REQUIRED GRADE OF THE UTILITY LINE. DO NOT COMPACT THE IMMEDIATE VICINITY 
ABOVE A UTILITY LINE UNTIL A FILL DEPTH OF AT LEAST 12-INCHES ABOVE THE UTILITY LINE IS REACHED. 
E. BRING COVERED SOILS TO FINISHED GRADES AS SHOWN IN THE APPROVED DRAWINGS. 1M MEDIATELY PROTECT THE COVERED SOIL MATERIAL FROM 
CONTAMINATION BY WATER BY COVERING WITH PLASTIC OR PL YWOOO. 
LOOP ROAD IMPROVEMENTS 
1011 SW LOOP ROAD 
OA~ 07-11-2011 
~' . . JOB NUMBER 1000 HAHCOO< ASSOOATES 
1500 SW LIXP ROAD 
llGARO, OR 97223 TIGARD OREGON 
,~~ # 
~# 
SHEET 
APPENDIX 12 
TAX LOT 1000 TAX WAP: 2S 1 09AB 
Ci ty of Tigard Urban l'orcstry Code Rc,·isions I \'olumc I\' I '15 

- - ·~- -----------------~--~~ 
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SOIL LEGEND SOIL VOLUME CALCULATION FOR STREET TREES ADJACENT TO LOT 1 
D 
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OPEN SOIL VOLUME 
TREE NUMBER 
COVERED SOIL VOLUfAE 
10023 
10024 
STREET TREE LEGEND 
SYIABOL BOTANICAL NAME 
SPECIES 
ARfASTRONG MAPLE 
ARfASTRONG MAPLE 
CO~~ON NAME 
OPEN SOIL COVERED SOIL TOTAL SOIL REQUIRED SOIL VOLME FOR 11' 
VOLUME (C.F.} VOLUfAE (C.F.} VOLUfAE (C.F.} RIGHT OF WAY (C.F.} 
6,453 45 6,498 500 
OVER 1,000 0 OVER 1,000 500 
CONDITION SIZE SPACING 
0 ACER RUBRU~ 'ARMSTRONG' ARMSTRONG I.W'l.£ 8&8 2' CAL K;SHOWN 
STREET TREE WITH COVERED SOIL DETAIL 
NOT TO SCALE 
ENCROACHMENT INTO THE ROOT PROTECTION ZONE IS ALLOWED WITH PROJECT ARBORIST 
APPROVAL AS DESCRIBED IN THE FOLLOWING NOTES: 
1. EXCAVATION IN THE TOP 24' OF THE SOIL IN THE CRITICAL ROOT ZONE AREA SHOULD BEGIN 
AT THE EXCAVATION LINE THAT IS CLOSEST TO THE TREE. 
2. THE EXCAVATION SHOULD BE DONE BY HAND/SHOVEL OR WITH A BACKHOE AND A MAN 
WITH A SHOVEL. PRUNING SHEARS. AND A PRUNING SAW. 
3.1F DONE BY HAND. All ROOTS 1' OR LARGER SHOULD BY PRUNED AT THE EXCAVATION LINE. 
4. IF DONE WITH A BACKHOE (MOST LIKELY SCENARIO) . THEN THE OPERATOR SHALL START 
THE CUT AT THE EXCAVATION LINE AND CAREFULLY ' FEEL' FOR ROOTS/RESISTANCE. WHEN 
THERE IS RESISTANCE. THE MAN WITH THE SHOVEL HAND DIGS AROUND THE ROOTS AND 
PRUNES THE ROOTS lARGER THAN 1' DIAMETER. 
IRRIGATION: 
IRRIGATION TO BE 'DESIGN-BUILD' BY THE lANDSCAPE CONTRACTOR. PROVIDE PlANS TO THE 
CITY FOR APPROVAL PRIOR TO BEGINNING INSTAllATION. 
REMOVAL, STORING, AND AMENDED SOILS FOR PlANTER AREAS: 
CONTRACTOR SHALL REMOVAL All DEBRIS FROM PlANTER AREAS AND EXCAVATE TO A 
DEPTH OF 36 1NCHES. SLOPE SIDES OF EXCAVATIONS AT 1:1 SLOPE OR SHORE EDGES TO 
PREVENT UNDERMINING OF VEHICLE LOAD AREAS AND TO PROVIDE A SLOPED PROFILE 
TRANSITION BETWEEN SOIL TYPES AND STRUCTURAL FILL. DISPOSE OF DEBRIS AND SUBSOIL. 
STOCKPILE EXCAVATED TOPSOIL IN APPROVED AREA OFF SITE. 
EXISTING AND IMPORTED TOPSOIL AMENDMENTS SHALL BE DETERMINED BY THE LANDSCAPE 
ARCHITECT AND APPROVED BY THE CITY ARBORIST. SOIL MIXING SHALL BE DONE IN 
DESIGNATED AREAS OR IN THE SUPPLIERS YARD. MIX AMENDMENTS WITH TOPSOIL WHEN 
SOIL IS IN A FRIABLE CONDITION ONLY ( DAMP AND NOT MUDDY WITH ADEQUATE MOISTURE 
TO BREAK INTO CLODS WHEN TURNED AND WILL NOT LEAVE A MUD STAIN ON THE HAND WHEN 
SQUEEZED) . CONTRACTOR TO PROVIDE CERTIFICATE OF CONTENT AND PERCENT OF SOIL 
MIXES WITH All AMENDED SOIL TO THE CITY PRIOR TO INSTAllATION. 
BLENDED SOIL PlACEMENT AND COMPACTION: 
SOIL SHALL BE FRIABLE WHEN PlACED AND COMPACTED. PlACE SOIL IN lAYERS OF NOT 
MORE THAN 12' 1N DEPTH. PROVIDE 3 PASSES WITH A 2' COMPACT PlATE VIBRATING 
COMPACTOR. COMPACT TO 80-85% MAXIMUM DRY DENSITY AS MEASURED BY THE PROCTOR 
TEST OR AS APPROVED FOR SPECIFIC BLENDED SOIL MIXES. 
KRJ 9A 
BOT AS~IIN 
STANDARD COVERED SOIL VOLUME SPECIFICATIONS: 
PART 1. COVERED SOIL MATERIALS 
A_ COVERED SOIL SHALL CONSIST OF THE FOLLOWING MIXTURE OF GRAVEL. SOIL AND ADMIXTURES: 
I. CRUSHED ROCK, GRADATION OF 100% PASSING 1.251NCH, MAX. 30% PASSING 0.75 1NCH: 
II. LOAM/ORGANIC TOPSOIL: 
Ill. SOIL BINDER SUCH AS , STABILIZER, : AND 
IV. WATER. 
PART 2. PROPORTIONS OF COVERED SOIL MATERIALS 
A_ THE PROPORTIONS OF COVERED SOIL MATERIALS SHALL BE AS FOLLOWS· 
MATERIAL AMOUNT FOR 1 CY OF COVERED SOIL AMOUNT FOR 4 CY OF COVERED SOIL 
CRUSHED ROCK 23.2 CUBIC FEET 4 CUBIC YARDS 
TOPSOIL 5.9 CUBIC FEET 1 CUBIC YARD 
SOIL BINDER 13.70Z 4LBS 
WATER 1.6GALLON 46GALLONS 
B. THE TARGET MOISTURE CONTENT IS 20% BY WEIGHT OF THE TOPSOIL WEIGHT. THE ABOVE WATER 
CONTENTS ASSUME THE TOP IS DRY. THE AMOUNT OF WATER THAT WILL NEED TO BE ADDED WILL BE 
DEPENDENT ON THE MOISTURE CONTENT OF THE RAW MATERIALS. ACTUAL AMOUNTS OF WATER 
USED SHALL BE DETERMINED DURING MIXING. 
PART 3. COVERED SOIL MIXING PROCEDURES 
A_ MIX COVERED SOIL IN BATCHES OF AN APPROPRIATE SIZE FOR THE EQUIPMENT BEING USED. THE END 
RESULT IS TO BE A MATERIAL THAT IS UNIFORMLY BLENDED TOGETHER. DO NOT BATCH IN QUANTITIES 
THAT WILL NOT ALLOW THE EQUIPMENT TO COMPLETELY MIX THE MATERIAL. DETERMINE BATCH SIZE 
AND QUANTITIES OF EACH MATERIAL NEEDED FOR THE BATCH. 
B. START WITH HALF OF THE CRUSHED ROCK MATERIAL. 
C. ADD All OF THE TOPSOIL MATERIAL. 
D. ADD THE SOIL BINDER. 
E. ADD HALF OF THE ESTIMATED WATER. 
F. ADD THE OTHER HALF OF THE CRUSHED ROCK MATERIAL. 
G. MIX THE MATERIAL TOGETHER. 
H. SLOWLY ADD WATER TO THE MIXTURE AND CONTINUE TO MIX. THE FINAL AMOUNT OF WATER WILL 
VARY WITH MOISTURE CONTENT OF THE CRUSHED ROCK AND TOPSOIL. ADD WATER IN INCREMENTAL 
AMOUNTS AND MIX THE MATERIAL BETWEEN THE ADDITIONS OF WATER. 
I. STOP ADDING WATER AND MIXING WHEN THERE IS A MINUTE AMOUNT OF FREE TOPSOIL REMAINING. 
THE TOPSOIL WILL COAT THE CRUSHED ROCK AND NOT FALL OUT OF THE MATERIAL. ALL OF THE 
CRUSHED ROCK SHALL BE UNIFORMLY COATED WITH TOPSOIL THERE SHALL BE NO CLUMPS OF 
TOPSOIL OR UNCOVERED CRUSHED ROCK IN THE MIXTURE. 
J. IF TOO MUCH WATER IS ADDED TO THE MIXTURE, WATER WILL DRAIN OUT OF THE MATERIAL AND THE 
TOPSOIL WILL WASH OFF OF THE CRUSHED ROCK. IF THIS OCCURS THE BATCH OF MATERIAL SHALL BE 
DISCARDED AND SHALL NOT BE INCORPORATED INTO THE COMPLETED WORK. 
PART 4. PlACEMENT OF COVERED SOIL 
A. PROTECT SOILS AND MIXES FROM ABSORBING EXCESS WATER AND FROM EROSION AT All TIMES. DO 
NOT STORE MATERIALS UNPROTECTED FROM RAINFALL EVENTS. DO NOT ALLOW EXCESS WATER TO 
ENTER SITE PRIOR TO COMPACTION. IF WATER IS INTRODUCED INTO THE MATERIAL AFTER GRADING, 
ALLOW MATERIAL TO DRAIN OR AERATE TO OPTIMUM COMPACTION MOISTURE CONTENT. 
B. All AREAS TO RECEIVE COVERED SOIL MIXTURE SHALL BE INSPECTED BY THE PROJECT lANOSCAPE 
ARCHITECT AND/OR PROJECT ENGINEER BEFORE STARTING PlACEMENT OF MIXTURE. All DEFECTS 
SUCH AS INCORRECT GRADING. COMPACTION AND INADEQUATE DRAINAGE. ETC .. SHALL BE 
CORRECTED PRIOR TO BEGINNING PlACEMENT OF COVERED SOIL. 
C. CONFIRM THAT THE SUB-GRADE IS AT THE PROPER ELEVATION AND COMPACTED AS REQUIRED. 
SUB-GRADE ELEVATIONS SHALL SLOPE PARALLEL TO THE FINISHED GRADE. CLEAR THE EXCAVATION 
OF All CONSTRUCTION DEBRIS, TRASH, RUBBLE AND FOREIGN MATERIAL. FILL ANY OVER EXCAVATION 
WITH APPROVED FILL AND COMPACT TO THE REQUIRED SUB-GRADE COMPACTION. 
D. INSTALL COVERED SOIL IN 6-INCH LIFTS AND SPREAD UNIFORMLY OVER THE AREA. COMPACT EACH 
LIFT TO THE REQUIRED MAXIMUM DENSITY. DElAY PlACEMENT 24 HOURS IF MOISTURE CONTENT 
EXCEEDS MAXIMUM ALLOWABLE. PROTECT COVERED SOIL WITH PtASTIC OR PlYWOOD OURING DElAY. 
TAKE PARTICULAR CARE NOT TO DAMAGE UTILITIES WHEN INSTALLING COVERED SOIL. COVERED SOIL 
THAT WILL BE THE BEDDING FOR UTILITY LINES SHALL BE COMPACTED TO CONFORM TO THE REQUIRED 
GRADE OF THE UTILITY LINE. DO NOT COMPACT THE IMMEDIATE VICINITY ABOVE A UTILITY LINE UNTIL 
A FILL DEPTH OF AT LEAST 12-INCHES ABOVE THE UTILITY LINE IS REACHED. 
E. BRING COVERED SOILS TO FINISHED GRADES AS SHOWN IN THE APPROVED DRAWINGS. IMMEDIATELY 
PROTECT THE COVERED SOIL MATERIAL FROM CONTAMINATION BY WATER BY COVERING WIT PlASTIC 
OR PLYWOOD. 
DATE: 07-11-2011 
~' JOB NUMBER 1000 1ST SfREt:T, SIITE I TtG<\RU, OREGON 97l2J 0£0(£1) 81': KRJ EVERGREEN HEIGHTS PARTITION 
190 SW 147TH ST. 
. . 2001 
SOIL VOLUME PLAN 
FOR SINGLE LOT 
PI! : (.'XH) 555-'('('('( 
FAX: (50:H 5.'l5-'('('t'( 
F\1\IL. 1\F()t ·\1--_CHII \BORATIVF_rtAI 
Llrf\Sf.ll I\ OR. l A, I. IU 
PREPAFED FOR: J(Hj SIIITH 
PO BOX Ill 
IIGARD, OREGON 9722J 
PI+. 50J-909-5555 
FU 50J-909-5556 
l.iry of'l'igard Urban 1:oresrry l.odc Rc,·isions I Volume 1\' I 97 
TIGARD OREGON 
TAXLOT 1100 TAXIIAP 2 4£ 25 
\~E~p 
<1PE# 
SHEET 
APPENDIX 13 

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TYPICAL LANDSCAPED FRONT 
YARD (OPEN SOIL VOLUME) 
OPEN SOIL VOLUME 
ROOT BARRIER PER 
]j ~ ,A.,. MANUFACTURER'S 
~ 
SPECIFICATIONS 
STREET 
COVERED SOIL 
VOLUME ROOT PATH 
(MINIMUM WIDTH 3') 
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COVERED SOIL VOLUME ROOT PATH 
PER CITY SPECIFICATIONS 
ROOT BARRIER PER MANUFACTURER'S 
SPECIFICATIONS 
I 
L COMPACTED SUBGRADE 
-RIGHT OF WAY WIDTH VARIES__j 
PROFILE 
City of Tigard Urban Forestry Code Revisions I Volume IV I 99 
EXAMPLE COVERED SOIL VOLUME 
PLAN DRAWING - ROOT PATH 
OPTION FOR STREET TREE 
NO SCALE 
DWG. NO. 
APPENDI X 14 
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LRIGHT OF WAY WIDTH VARIES---I 
PROFILE 
City of Tigard Urban l'orcstry Code Rc,·isions I \'olumc 1\' I tr!U 
EXAMPLE COVERED SOIL VOLUME 
PLAN DRAWING - UNDER SIDEWALK 
OPTION FOR STREET TREE 
NO SCALE 
DWG. NO. 
APPENDIX 14 
Example Covered Soil Volume Specifications 
Part 1. Covered Soil Materials 
A. Covered soil shall consist of the following mixture of gravel, soil and admixtures: 
1. Crushed rock, gradation of 100% passing 1.25 inch, max. 30% passing 0.75 inch; 
2. Loam/Organic Topsoil; 
3. Soil binder such as "Stabilizer"; and 
4. Water. 
Part 2. Proportions of Covered Soil Materials 
A. The proportions of covered soil materials shall be as follows: 
Material Amount for 1 CY Amount for 4.6 CY 
of Covered Soil of Covered Soil 
Crushed Rock 23.2 cubic feet 4 cubic yards 
Topsoil 5.9 cubic feet 1 cubic yard 
Soil Binder 13.7 ounces 4 pounds 
Water 1.6 gallon 46 gallons 
I 
B. The target moisture content is 20% by weight of the topsoil weight. The above water 
contents assume the top is dry. The amount of water that will need to be added will be 
dependent on the moisture content of the raw materials. Actual amounts of water used shall 
be determined during mixing. 
Part 3. Covered Soil Mixing Procedures 
A. Mix covered soil in batches of an appropriate size for the equipment being used. The end 
result is to be a material that is uniformly blended together. D o not batch in quantities that 
will not allow the equipment to completely mix the material. D etermine batch size and 
quantities o f each material needed for the batch. 
B. Start with half of the crushed rock material. 
C. Add all of the topsoil material. 
D . Add the soil binder. 
E. Add half of the estimated water. 
F. Add the other half of the crushed rock material. 
G. Mix the material together. 
H . Slowly add water to the mixture and continue to mix. The final amount of water will vary 
with moisture content of the crushed rock and topsoil. Add water in incremental amounts 
and mix the material between the additions of water. 
I. Stop adding water and mixing when there is a minute amount of free topsoil remaining. The 
topsoil will coat the crushed rock and not fall out of the material. All of the crushed rock 
Appendix 14 
Ciry of Tigard Urban l'o rcst ry Code Rc,·isions I Volume 1\' I 101 
shall be unifo rmly coated with topsoil . T here shall be no clumps o f topsoil o r uncovered 
crushed rock in the mixture . 
.J. If too much wa ter is added to the mixture, wa ter will drain out o f the material and the 
topsoil will wash o ff o f the crushed rock. If this occurs the batch o f m aterial shall be 
discarded and shall not be incorporated into the completed work. 
Part 4. Placement of Covered Soil 
A. Pro tect soils and mixes from absorbing excess water and from erosion at all times. D o no t 
store materials unpro tected from rainfall events. D o no t allow excess wa ter to enter site 
prior to compaction. If water is introduced into the material after grading, allow material to 
drain o r aerate to optimum compaction moisture content. 
B. All areas to receive covered soil mixture shall be inspected by the pro ject landscape architect 
and / or project engineer before starting placement o f mixture. All defects such as incorrect 
grading, compac tio n and inadequate drainage, etc., shall be corrected prior to beginning 
placement o f covered soil. 
C. Confirm that the sub-grade is at the proper elevation and compacted as required. Sub-grade 
elevations shall slope parallel to the fini shed grade. Clear the excavation o f all construction 
debris, trash, rubble and foreign material. Fill any over excava tion with approved fill and 
compact to the required sub-grade compaction . 
D . Install covered soil in 6-inch lifts and spread uniformly over the area. Compact each lift to 
the required percent o f maximum density . D elay placement 24 hours if moisture content 
exceeds maximum allowable, protect covered soil with plas tic or plywood during delay. 
Take particular care not to damage utilities when installing covered soil. Covered soil that 
will be the bedding fo r utili ty lines shall be compacted to conform to the required grade o f 
the utili ty line. D o no t compact the immediate vicinity above a utility line until a fill depth o f 
at leas t 12-inches above the utili ty line is reached. 
E . Bring covered soils to fini shed grades as shown in the approved drawings. Immediately 
pro tect the covered soil material from contamination by water by covering with plastic or 
plywood. 
A ppendix 14 
Cit y oiTigard Urban l:orcstry Code RcYisions I \ 'ulumc 1\ ' I lil2 
TREE 'A' 
34' 
rD 
PLAN 
PARKING LOT SURFACING 
COMPACTED SUBGRADE 
PROFILE 
TOTAL SOIL VOLUME CALCULATION FOR TREE 'A': 
OPEN SOIL VOLUME= (ISLAND AREA) X (SOIL DEPTH) = 336 S.F. 
X 3' = 1,008 C.F. 
COVERED SOIL VOLUME= 0 C.F. 
TOTAL SOIL VOLUME= OPEN SOIL VOLUME+ COVERED SOIL 
VOLUME = 1,008 C.F. + 0 C.F. = 1,008 C.F. 
1,008 C.F. IS GREATER THAN THE SOIL VOLUM E REQUIRED FOR 
A PARKING LOT TREE (1 ,000 C. F.) SO THIS MEETS THE CITY 
REQUIREMENTS. 
EXAMPLE SOIL VOLUME 
CALCULATION - PARKING 
LOT TREE WITH OPEN SOIL 
Ciry or Tigard Urban Forestry Code Rc,·isions I Volume I\' I 103 
NO SCALE 
DWG. NO. 
APPENDIX 15 
3' I • I • I 
+ 
+ 
+ 
3'----t--1 
OPEN SOIL VOLUME 
1---o-.t---3' 
+ 
+ 
+ 
PLAN 
TREE 'A' 
I 
COVERED SOIL VOLUME 
UNDER ASPHALT 
1n 
OPEN SOIL VOLUME 
PARKING LOT SURFACING 
~~~~~~~~~~----COVERED SOIL VOLUME 
~~~~~-----COMPACTEDSUBGRADE 
DRAINAGE 
PROFILE 
TOTAL SOIL VOLUME CALCULATION FOR TREE 'A': 
OPEN SOIL VOLUME= (PLANTER AREA) X (SOIL DEPTH)= 196 S.F. 
X 3' = 588 C.F. 
COVERED SOIL VOLUME= 259 S.F. X 3' = 777 C.F. 
TOTAL SOIL VOLUME= OPEN SOIL VOLUME+ COVERED SOIL 
VOLUME= 588 C.F. + 777 C.F. = 1,365 C.F. 
1,365 C.F. IS GREATER THAN THE SOIL VOLUME REQUIRED FOR A 
PARKING LOT TREE (1 ,000 C.F.) SO THIS MEETS THE CITY 
REQUIREMENTS. 
EXAMPLE SOIL VOLUME 
CALCULATION - PARKING LOT 
TREE WITH COVERED SOIL 
City of Tigard Urban Fo rc>try Code Rc,·i> iom I \'olumc I\ ' I 1114 
NO SCALE 
DWG. NO. 
APPENDIX 15 
TOTAL SOIL VOLUME CALCULATION FOR TREE 'A': 
OPEN SOIL VOLUME= 36 S.F. (TREE CUTOUT AREA)+ 36 S.F (CONNECTED TREE CUTOUT AREA) x 3' (SOIL DEPTH) = 216 C.F. 
COVERED SOIL VOLUME = 330 S.F. (COVERED SOIL AREA) X 3' (COVERED SOIL DEPTH' =990 C.F 
TOTAL SOIL VOLUME= OPEN SOIL VOLUME+ COVERED SOIL VOLUME= 216 C. F. + 990 C.F.=1 ,206 C. F. 
1,206 C. F. IS GREATER THAN THE SOIL VOLUME REQUIRED FOR A PARKING LOT TREE (1000 C.F) SO THIS MEETS THE CITY 
REQUIREMENTS. 
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SOIL VOLUME) 
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(OPEN SOIL VOLUME) 
EXAMPLE SOIL VOLUME 
CALCULATION - PARKING 
LOT TREE WITH ROOT PATH 
City o f Tigard Urban l'orcstry Code Rc,·isions I Vo lume IV I 105 
NO SCALE 
DWG. NO. 
APPENDIX 15 

/ 
' 
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!REVISIONS: 
'-.. 
/ 
AV~!Jili OPEN 
SOIL (TYP.) 
'-.. 
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~ 
PLANT LEGEND TREE CANOPY TABLE 
AVfJIJG£ IMME OPEN SOIL VOLUME COVERED SOIL VOLUME TOTAL SOIL VOLUME AVE. MATURE CANOPY %OF CANOP Y OVER PARt<ING LOT 
SliA8Q. aTIES. _ QQTANCIL _______ C()IIj()N NAIIE ~ZE COHOOION SPIONG CANCI'r SIZE 
TREE I 
001 
002 
003 
004 
005 
006 
007 
008 
009 
010 
011 
0012 
0013 
0014 
0015 
0016 
0017 
0018 
0019 
0020 
0021 
0022 
0023 
0024 
0025 
0026 
0027 
0026 
0029 
0030 
0031 
0032 
0033 
0034 
0035 
0036 
0037 
0036 
0039 
0040 
0041 
0042 
SPECIES 
Zelko,. 
Red Oak 
Z..Ok ... 
5,466 e.f. Oc.f. 5,466c.l. 50' spread {1,963t.f.) 39% 
4,539 c.f. Oc.f. 4,539 c. t 45' spread {1,5905.l ) 40% 
AREA OVER PARtaNG LOT 
7~s.f. 
640s.f. 
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BUILDING FOOTPRINT 
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AS SHOWN 40' SPROO (1,256 SF.) 
AS SHOWN 45' SPROO (1,590 SF.) 
AS SHOWN 50' SPROO (1,963 SF.) 
SCALE SHOWN IS FOR FUU 
SIZE SHEET ( 24"X361 ONLY 
SC ALE I" = 20 FEET 
----~ .!"'! .PU 
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Rod Qak 
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Rod Qak 
Zalkow 
"''""' 
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"''""' ZolkOYO
Red Oak 
"''""' 
"''"'" 
"''""' Rod Qak 
"''"'" Red Oak 
"''""' Red Maple 
Red Maple 
RedNaple 
Red Maple 
Red Maple 
Red Maple 
Red Maple 
Z..Ok .... 
3,192c.f. Oc.f. 3,192c.f. 50' spread(1 ,963s.f. ) 92% 
3,069 c.f. 0 c.f. 3,069 c.t 50' spread (1 ,963 s.f.) 89% 
1,818 c. f. 0 c .f. 1,818 c.l 50' spread (1,963 s .l ) 53% 
303 c. f. 2,160 c.f. 2,463 c.l 50' spread (1,963 s .f.) 50% 
348 c.l 2,160 c.f. 2,508 c.t 50' spread (1.963 s.t.) 80% 
576 c.l 2.166 c.f. 2,742 c .l 50' spread (1.963 s.f.) 85% 
3,681 c.f. 0 c.f. 3,681 c. I. 50' spread (1,963 s.f. ) 76% 
4,200 c. f. 0 c.t. 4,200 c. I. 45' spread (1,590 s .l ) 35% 
708c.l 2.076c.f. 2,7&4c.l 50'spread (1,963s.f. ) 82% 
3,651 cJ. 0 c.f. 3,651 c. t 50' spread (1,963 s.t ) 79% 
1,101 c.f. Oc. f. 1,101 c.t 50' spread (1,963 d ) 100% 
1,101 cJ. 0 c.f. 1,101 c.t 50' spread (1,963 s.f.) 100% 
4,155c.f. Oc.f. 4,155c.l 45'spread (1,590s.l ) 36% 
4,176 c. f. 0 c.f. 4,176 c.{ 50' spread (1,963 s.t ) 11)1)% 
4,233 c.f. 0 c.f. 4,233 c. f. 50' spread (1,963 s.l ) 11)1)% 
4,233 c.f. 0 c.f. 4,233 c.f. 50' spread (1,963 s.l ) 11)1)% 
3,630c.f. Oc.f. 3,630c.f. SO'spread(1 ,963s.l ) 79% 
4,506c.f. 0 c.f. 4,506 c. t 45' spread (1 ,590 s.t ) 41% 
417 c.f. 870 c.f. 1,287 c.t 50' spread (1 ,963 s.f.) 100% 
444 c.f. 870c .f. 1,314 c.t 50' spread (1 ,963 s.f.) 100% 
4,293 c.t 870 c.f. 5,163 c.t 50' lipread (1 ,963 s.f.) 100% 
4,284c.t 870c.f. t 5,154c.t SO'spread (1,963s.f.) tOO% 
4,284 c.t 870 c.l 5,154 c.f. 50' spread {1,963 s.f. ) 11)()% 
~: ~:i ~~:i + ~: ~:~ ~::::g :~~::::~ ~ 
2,430 c.l Oc.t t 2,430 c.t 50' 5pread (1,963 s.f.) 79% 
1,onc.t Oc.t t t ,onc.t SO'spread(1 ,963s.f.) 100% 
1,077 c.l 0 c.t t 1,0n c.l 50' spread (1,963 s.f.) 100% 
4,191 c.t 0 c.{ 4,191 c.l 45' spread (1 .590 d .) 40% 
3,630 c.t 0 c.t 3,630 c.t 50' spread (1 ,963 s.t ) 80% 
4,392 c.f 0 c.t 4,392 c.f 45' spread (1,590 s.f.) 38"' 
7,350 c.t 0 c.l 7,350 c.f SO' spread (1,963 s.t. ) 45% 
1,416c.f Oc. t. 1,416c.f 40'spread (1,256s.f. ) 100% 
1,989c.f Oc.l 1,989c.f 40'spread(1 .256s.f.) 1()()% 
2.562 c.f 0 c.t 2,562 c.f 40' spread (1,256 s.f.) 100% 
2,529 c.l 0 c.l 2,529 c.l 40' spread (1.256 s.f.) 73% 
1,533 c.f 0 c.l 1,533 c.f 40' spread (1.256 s.f.) 53% 
516 c.l 1,716 c.f. 2,232 c.f. 40' spread (1 ,256 s.f.) 81% 
516 c.t 1,716c.f. 2,232 c.f. 40' spread (1 ,256 s.f.) 80% 
837c.f. 441 c.f. 1,278c.f. 50'spread(1 ,963s.f.) 92% 
1,812s.f. 
1,749s.f. 
1.040s.f. 
984s.f. 
1,575 s. f. 
1,668s.f. 
1,498s.f. 
559s.f. 
1,613s.f. 
1.550s.f. 
1,963s.f. 
1,963s.f. 
566s.f. 
1,963s.f. 
1,963 s. f. 
1,963s.f. 
1,547 s.f. 
644s.f. 
1,963s.f. 
1,963s.t. 
1,963s.f. 
1,963s.f. 
1,963s.f. 
936s.f. 
531 s .f. 
1,55as.f. 
1,963s.f. 
1,963s.f. 
642s.f. 
1,563s.l 
602s.f. 
882s.f. 
1,256s.l 
1,256s.l 
1,2565.{ 
915s.f. 
72!3s.f. 
1,021 s.l 
1,007s.t 
1,804 s.l 
Total Qualifying Mann Tree C3n0py Area: ~. 763 s.t 
(SUm cf c.,opy •ea oo.er paridng lot) 
QUAUFYING MATURE CANOPY INCLUDES ALL AREAS DIRECTLY OVER THE PARKING LOT SURFACE AND AREAS THAT ARE SURROUNDED ON AT LEAST THREE SIDES BY EITHER CURB OR 
HARD SURFACE PAVING. THIS INCLUDES BUT IS NOT LIMITED TO PARKING LOT ISLANDS AND PLANTING AREAS BETWEEN THE PARKING LOT AND SIDEWALK. 
D QUAliFYING MATURE CANOPY COVER 
INOMDUAL TREE MATURE CANOPY OUTLINE 
PARKING LOT AREA: 64,962 S.F. 
TOTAL OUAUFYING MATURE TREE CANOPY AREA•: 57,763 S.F. 
( CANOPY AREA OIRECTL Y OVER PARKING LOT) 
% CANOPY COVER: 89% 
MlNIMUM % CANOPY COVER: 30% 
89% IS GREATER THAN THE MINIMUM OF 30% TOTAL QUALIFYING 
MATURE CANOPY COVER THEREFORE CITY REQUIREMENTS ARE 
MET. 
REMOVAL. STORING, AND AM ENDED SOILS FOR PLANTER AREAS: 
~ OPEN SOIL VOLUME 
COVERED SOIL VOLUME 
PARKING LOT TREE SOIL VOLUME REQUIREMENTS 
MIN. SOIL VOLUME REQUIREMENT ( C.F. PER TREE) 
t,OOOC.F. 
CONTRACTOR SHALL REMOVAL ALL DEBRIS FROM PLANTER AREAS AND EXCAVATE TO A DEPTH OF 36 1NCHES. SLOPE SIDES OF EXCAVATJONS AT 1:1 SLOPE OR 
SHORE EDGES TO PREVENT UNDERMINING OF VEHICLE LOAD AREAS AND TO PROVIDE A SLOPED PROFILE TRANSITION BETWEEN SOIL TYPES AND STRUCTURAL 
FILL DISPOSE OF DEBRIS AND SUBSOIL STOCKPILE EXCAVATED TOPSOIL IN APPROVED AREA OFF SITE. 
EXISTING AND IMPORTED TOPSOIL AMENDMENTS SHALL BE DETERMINED BY THE LANDSCAPE ARCHITECT AND APPROVED BY THE CITY ARBORIST. SO.l MIXING 
SHAll. BE DONE IN DEStGNA TEO AREAS OR IN THE SUPPLIERS YARD. MIX AMENDMENTS W ITH TOPSOIL WHEN SOIL IS IN A FRIABLE CONCHTION ONLY ( DAMP AND 
NOT UUOOY WITH ADEQUATE MOISTURE TO BREAK INTO CLODS WHEN TURNED AND WILL NOT LEAVE A MUD STAIN ON THE HAND WHEN SOUEEZEIJJ • 
CONTRACTOR TO PROVIDE CERTIFICATE OF CONTENT AND PERCENT OF SOIL MIXES WITH All AMENDED SOIL TO THE CITY PRIOR TO INSTA.L.LATION. \'~~\,\ 
\ \ 
\ \ / 
BLENDED SOk. PLACEMENT AND COMPACTION: 
SOIL SHAll BE FRlABLE WHEN PLACED AND COMPACTED. PlACE SOIL IN LAYERS OF NOT MORE THAN 12" IN DEPTH. PROVIDE 3 PASSES WITH A 2" COMPACT 
PLATE VIBRATING COMPACTOR. COMPACT TO 80-85% MAXIMUM DRY DENSITY AS MEASURED BY THE PROCTOR TEST OR AS APPROVED FOR SPECIFtC BLENDED 
sotL MIXES. 
~ / 
\ )..":..: 
/\ \ 
/ \, 
\ 
\ 
\ \\ 
\\ 
\\ 
'\ \\ 
\ \ 
\\ 
.. \ 
\\ 
\\ 
.. 
\ 
~ 
n:; ')t1~--;-t II~~ I l j";';lllfh' COVERED SOIL VOLUME 
,,,....,....,, ' ''' COMPACTEOSUBGRAOE 
CUR 
PARKING TREE WITH COVERED SOIL DETAIL 
NOT TO SCALE 
DATE: 07- 11-201 1 
EXAMPLE PARKING LOT 
TREE CANOPY PLAN 
~ AS NOTED ~~:t~~~~:~::t~;TE I ABc j!O<tml!!!! .. W!""li.·-------:-
P11: (;;().\) 555-HH PAEPAFED fOA: 
rA:< · cso:l) ~:l~-nn I RD 
,,;;, 1>F00\1lf_f01 1 """'"" ro• COLLABORAT I VE ''"""'· "' "UJ TJGA 
LOOP ROAD IMPROVEMENTS 
1011 SW LOOP ROAD ~' . . \~~k 
<1i>E# 
JOO NUt.I8£R 
1000 
LICI:"\St:IJ l\j OK. I'A , l Ill ~,.; >;H'JI I,.; • ~II<Mm• n~tt • "'""..,.· • • ... ,~ m- AlhHII¥<ultt· TAX LOT 1000 
Ciry of Tigard Urban l'orcstry Code Rc,·isions I Volume 1\' I 107 
OREGON 
TAX liN' 25 I 09AB 
SHEET 
APPENDfX 16 
.,. 
s: 
I~ §t 
LANDSCAPE ISLAND (OPEN SOIL VOLUME) 
~ T"""""T ....,.- + ----;""" r + -.,..-~ 
4- + + + + + + / + + + + I COVERED SOIL VOLUME 
+ + + + rr- UNDER ASPHALT 
+ + + +. 
+ + + + 
++++ ++++ 
I + + + + + + ~ 
fi- ++ +++ I 
+ + + + + 
ft- + + + + I 
I + + + + -+J 
+ + + + + 
L + + + + 1 r- + + + + 
-< v'AfrE~ VARIEs+L-
t + + ++++ J ~ + + + + 1 
I. + + r- + + 
+ + 
~ + + + + + + 
+ +1 + + 
+ + 
+ + j+. 
+ + 
+ + 
4- ++++ ~ 
+ + + I 
+ + + + ~~+ + + 
+ + + + + + + + + 
I + + + + + + + + + + ~ 
+ + + + + + + + CURB + 
1 ++++++++++ -+i ~ --I-- I~ ~ I ~ J.-1 .--L-.1 
PLAN 
n 
PARKING LOT SURFACING 
PROFILE 
EXAMPLE COVERED SOIL VOLUME 
PLAN DRAWING - UNDER 
PARKING LOT OPTION FOR 
PARKING LOT TREE 
City of T igard Urban Forc>try Code Rc,·isions I Volume IV I 109 
NO SCALE 
DWG. NO. 
APPENDIX 17 
PLAN 
COVERED SOIL VOLUME 
ROOT PATH (3' MINIMUM) 
6'X6' MINIMUM TREE CUTOUT 
(OPEN SOIL VOLUME) 
ECTED TREE CUTOUT 
It VARIES f-----4-----
RB 
6'X6' MINIMUM TREE CUTOUT 
(OPEN SOIL VOLUME) 
PLAN 
CONNECTED TREE CUTOUT 
(OPEN SOIL VOLUME) 
PROFILE 
COVERED SOIL VOLUME (ROOT PATH) 
PER CITY SPECIFICATIONS 
EXAMPLE COVERED SOIL 
VOLUME DRAWING- ROOT 
PATH OPTION FOR PARKING 
LOT TREE 
City of T igard Llrban l'orcstry Code Rc,·i<ions I \'olumc 1\' I II II 
NO SCALE 
DWG. NO. 
APPENDIX 17 
Example Covered Soil Volume Specifications 
Part 1. Covered Soil Materials 
A. Covered soil shall consist of the following mixture of gravel, soil and admixtures: 
1. Crushed rock, gradation of 100% passing 1.25 inch, max. 30% passing 0.75 inch; 
2. Loam/Organic Topsoil; 
3. Soil binder such as "Stabilizer"; and 
4. Water. 
Part 2. Proportions of Covered Soil Materials 
A. The proportions o f covered soil materials shall be as follows: 
Material Amount for 1 CY Amount for 4.6 CY 
of Covered Soil of Covered Soil 
Crushed Rock 23.2 cubic feet 4 cubic yards 
Topsoil 5.9 cubic feet 1 cubic yard 
Soil Binder 13.7 ounces 4 pounds 
Water 1.6 gallon 46 gallons 
B. T he target moisture content is 20% by weight of the topsoil weight. The above water 
contents assume the top is dry. The amount of water that will need to be added will be 
dependent on the moisture content of the raw materials. Actual amounts of water used shall 
be determined during mixing. 
Part 3. Covered Soil Mixing Procedures 
A. Mix covered soil in batches of an appropriate size for the equipment being used. The end 
result is to be a material that is uniformly blended together. D o not batch in quantities that 
will not allow the equipment to completely mix the material. D etermine batch size and 
quantities of each material needed for the batch. 
B. Start with half of the crushed rock material. 
C. Add all of the topsoil material. 
D . Add the soil binder. 
E. Add half of the es timated water. 
F. Add the other half o f the crushed rock material. 
G. Mix the material together. 
H . Slowly add water to the mixture and continue to mix. The final amount of water will vary 
with moisture content of the crushed rock and topsoil. Add water in incremental amounts 
and mix the material between the additions o f water. 
I. Stop adding water and mixing when there is a minute amount of free topsoil remaining. The 
topsoil will coat the crushed rock and not fall out of the material. All of the crushed rock 
Appendix 17 
City of Tigard Urban Fo restry Code Rc,·isions I Volume IV I 111 
shall be uniformly coated with topsoil. There shall be no clumps o f topsoil o r uncovered 
crushed rock in the mixture. 
]. If too much water is added to the mixture, water will drain out o f the material and the 
topsoil will wash off of the crushed rock. If this occurs the batch o f material shall be 
discarded and shall not be incorporated into the completed work. 
Part 4. Placem ent of Covered Soil 
r\. Pro tect soils and mixes from absorbing excess water and from erosio n at all times. D o not 
store materials unprotected from rainfall events. D o not allow excess water to enter site 
prior to compaction. If water is introduced into the material after grading, allow material to 
drain or aerate to optimum compaction moisture content. 
B. All areas to receive covered soil mixture shall be inspected by the pro ject landscape architect 
and / or pro ject engineer before starting placement of mixture. All de fects such as incorrect 
grading, compaction and inadequate drainage, etc., shall be corrected prior to beginning 
placement of covered soil. 
C. Confirm that the sub-grade is at the proper eleva tion and compacted as required. Sub-grade 
eleva tions shall slope parallel to the fini shed grade. Clear the excavation o f all construction 
debris, trash, rubble and fo reign material. Fill any over excavation with approved fill and 
compact to the required sub-grade compaction. 
D . Install covered soil in 6-inch lifts and spread uniformly over the area. Compact each lift to at 
least 85 percent o f maximum density. D elay placement 24 hours if moisture content exceeds 
maximum allowable, pro tect covered soil with plastic or plywood during delay. Take 
particular care not to damage utilities when installing covered soil . Covered soil that will be 
the bedding for utility lines shall be compacted to conform to the required grade of the 
utili ty line. D o not compact the immediate vicinity above a utility line until a fill depth of at 
leas t 12-inches above the utility line is reached. 
E. Bring covered soils to fini shed grades as shown in the approved drawings. Immediately 
pro tect the covered soil material from contamination by water by covering with plastic or 
plywood . 
Appendix 17 
Cir,· of Tigard Urban l;orcstry Co<k Rc,·isions I \ 'olumc 1\ ' I 11 2 
I 
I 
\ 
\ 
' 
PLANTER 
\ 
\ 
' 
.-
ARKING AREA BOUNDARY 
- / 
WHITE ASH (TYP.) 
\._ 45' DIA. MATURE CANOPY (TYP.) 
1,590 S.F. 
' 
' \ 
I 
I 
I 
123:.00' 
RED MAPLE (TYP.) 
40' DIA. MATURE CANOPY (TYP.) 
(1,256 S.F. 
' I 
' \ 
I 
I 
I 
/ 
' 
/ 
' 
/ 
-
.-
-
.-
........ / 
TOTAL CANOPY AREA OF PARKING LOT TREES* = 11,388 S.F. 
TOTAL QUALIFYING MATURE CANOPY COVER= CANOPY COVER DIRECTLY OVER THE PARKING AREA IN SQUARE 
FEET, INCLUDING PLANTING ISLANDS AND AREAS SURROUNDED BY CURB OR HARD SURFACE PAVING ON AT 
LEAST THREE SIDES. 
~ TOTAL QUALIFYING MATURE CANOPY COVER= 8,057 S.F. 
PARKING LOT AREA= 13,590 S.F. 
PERCENT ACTUAL CANOPY COVER= (8 ,057 S.F.) I (13,590 S.F.)= 59% 
59% IS GREATER THAN THE MINIMUM OF 30% TOTAL QUALIFYING MATURE CANOPY COVER 
THEREFORE CITY REQUIREMENTS ARE MET. 
*CANOPY AREA PER TREE IS DETERMINED FROM THE VALUE GIVEN IN THE CITY OF TIGARD PARKING LOT TREE 
LIST FOR A MATURE TREE OF THAT SPECIES. 
EXAMPLE PARKING LOT 
THAT MEETS 30% MINIMUM 
CANOPY COVER 
REQUIREMENT 
City of Tigard Urban Forestry Code Rc,·isions I \' olumc I\ ' I 113 
NO SCALE 
DWG. NO. 
APPENDIX 18 
City of Tigard 
COMJ\ifUNI1Y DEVELOPMENT DEPARTMENT 
13125 SW Hall Blvd., Tigard, OR 97223 
W'.VW. tigard-or.gov / trees I 
Acknowledgements 
Tigard City Council 
Mayor Craig Dirksen 
Council President G retchen Buehner 
Councilor Marland Henderson 
Councilor Nick Wilson 
Councilor Mark Woodard 
Tigard Planning Commission 
D ave Walsh, President 
Tom Anderson, Vice President 
Dianne Armstrong 
Margaret D oherty 
Calista Fitzgerald 
Andrew Miller 
Matthew Muldoon 
Karen Ryan 
Jason Rogers 
D onald Schmidt 
Richard Shavey 
Citizen Advisory Committee 
Scott Bernhard, D C, Parks and Recreation 
Advisory Board 
John Frewing, Citizen at Large 
Ken Gertz, Portland Metropolitan H ome 
Builders 
Morgan E . H olen, ISA Certified Arborist 
Bret Lieuallen, Tree Board 
D on Schmidt, Planning Commission 
Tony Tycer, T ree Board 
D ave Walsh, Planning Commission 
Brian Wegener, Tualatin Riverkeepers and 
Board Member o f O R Community T rees 
John Wyland, D eveloper 
Project Managem ent Team 
Todd Prager, Associate Planner & City 
Arborist, Project Manager 
Marissa D aniels, Associate Planner, Public 
Involvem ent Lead 
Susan H artnett, Assistant Community 
D evelopment Director 
D arren Wyss, Senior Planner 
Cheryl Caines, Associate Planner & Code 
E ditor 
John Floyd, Associa te Planner 
Gary Pagenstecher, Associate Planner 
Technical Advisory Committee 
Mark Buffington, O D OT Region 1 
Landscape Manager 
G us Duenas, D evelopment E ngineer 
Ted Kyle, City E ngineer 
Ron Kroop, O D OT District 2A Manager 
Steve Martin, Parks and Facilities Manager 
Brian Rager, Assistant Public Works Director 
D amon Reische, Clean Water Services 
Nate Shaub, G IS Analys t 
Albert Shields, Program D evelopmen t 
Specialist 
Carla Staedter, Surface Water Quality 
Coordinator 
Greg Stout, G rounds and Open Space 
Coordinator 
Mark Van D omelen, Building Official 
Vance Walker, Streets Supervisor 
Additional T igard Staff Contributors 
Marty Wine, City Manager 
Ron Bunch, Community D evelopment 
Director 
D ennis Koellermeier, Public Works Director 
Tom McG uire, Principal Planner 
D oreen Laughlin, Confidential Executive 
Assistant 
Tim Lehrbach, Temporary Planning Assistant 
Consultant Team 
Adrienne D eD ona, JLA Public Involvment 
G reg Winterowd, Winterbrook Planning 
KeithJehnke, AKS E ngineering and Fores try 
Kirsti Hauswald, AKS E ngineering and 
Forestry 
" 
Community attitude sttrvrys reveal that 
Tigard Citizens place high value on the 
protection of trees and are concerned about 
the impact of development ttpon existing 
tree resources. 
· figard Comprehensive Plan 
Table of Contents 
Project Introduction ................................. .................................................................. ........ ...... .. .. .. ................... .. ..... ................ .... 1 
Problem Statement 
Goals Statement 
Collaborative Process 
Key E lements of Proposal 
Urban Forestry Standards for D evelopment (fitle 18) 
T ree G rove Preservation Incentives (fitle 18) 
Tree Permit Requirements (fide 8) 
H azard Trees (fitle 8) 
1 
2 
2 
3 
3 
3 
3 
4 
Proposal Summary ... .......... .......... ..... .. ....... .. ...... .... ................... ....... .... ............................ ............ ......................... ...... .... .... .... ..... . 8 
Tree Canopy Approach ... ..... ........ ........... .... ................. .... ........ ... ........... ...... .............................. ................. ................ ...... .... .. 9 
Tree Canopy Regulations 12 
Implementation: Urban Fores try Manual. .... ... ... ...... ........................... ....... ... ...... ........... ..... ...... .............. ...... ... .. ................ 14 
Tree Grove Preservation Incentives 
Resolution of H azard Tree Situations 
H eritage Tree and Significant Tree Program 
Tree Removal Permits 
Urban Forestty Manual 
Appendix: Additional D etails 
• Process Summaty 
• Summary of Community Ideas and Concerns 
• Summary of Planning Commission D eliberations 
• Existing Conditions 
17 
20 
22 
23 
25 
26 
Project Introduction 
T he City o f Tigard has a proud history o f commitment to preserving, 
enhancing and maintaining its urban forest. The city's trees provide an 
important backdrop for life in Tigard. Unlike natural forests or managed 
timberland, Tigard's urban forest is a mosaic of native forest remnants and 
planted landscapes interspersed with buildings, roads and other elements o f 
the built environment. T o implement Tigard's Comprehensive Plan as 
recommended by the Urban Forestry Master Plan, City Council set forth a 
vision that "Tigard's urban forest is valued and protected by city residents as 
a thriving, interconnected ecosys tem managed to improve quality of life, 
increase community identity, and m aximize aes thetic, economic and 
ecological benefits." 
In pursuit o f this vision , council directed staff to undertake the major update 
of Tigard's urban forestry related code provisions described in the Master 
Plan . Council intends the new and updated code language to more adequately 
reflect the needs o f our changing and growing community. 
Problem Statement 
During the Urban Fores try Master Plan process, a wide range o f 
stakeholders, including community groups, developers and staff, identified 
concerns about the city's current tree regulations. Key concerns included: 
• 
• 
• 
• 
• 
• 
• 
• 
The code does not prom ote the preservation of high quality trees . 
The mitigation structure encourages overplanting and the 
preservation of large diameter trees that are often less likely to 
survive development impacts. 
The fees for tree rem oval are excessive . 
The code unfairly burdens those property owners with existing trees 
m ore than those owners without trees. 
The code is administratively difficult to implem ent because it is 
challenging to track protected and replacement trees in the years and 
decades following development. 
T he code lacks specificity and has conflicts between various 
provisions, which creates administrative challenges and confusion . 
T he code does not require sustainable installation and m aintenance 
methods for trees. 
The code does not provide flexible standards and incentives for 
preserving native tree groves. 
City of Tigard Urban Forestry Code Revisions I Volume I I 1 
The Urban Forestry Master 
Plan is included in its entirety 
in Volume V. 
1 
Goals Statement 
Following adoption of the Urban Fores try Master Plan, council directed staff 
to undertake the Urban Forestry Code Revisions project including: 
1. Update Tigard's urban forestry standards for development. 
2. E nsure urban fores try standards promote sustainable design and 
maintenance o f the urban forest. 
3. Establish an incentive-based program to preserve Tigard's remaining 
groves of native trees. 
4. D evelop an equitable and efficient hazard tree identification and 
abatement program. 
5. Improve managem ent o f the urban forest by ensuring information is 
readily available for bo th the city and the public when mailing 
decisions. 
6. P romote community-wide participation in urban fores t stewardship. 
Collaborative Process 
As described above, the Urban Forestry Code Revisions project represents 
the convergence o f community collaboration on several urban forestry 
related projects. Community input was integral to the completion of both the 
Urban Forest section o f the Comprehensive Plan and the Urban Forestry 
Master Plan . Public involvement for the Urban Forestry Code Revisions has 
built on these previous efforts. Led by the Con'lmunity D evelopment 
D epartmen t, the Urban Fores try Code Revisions Project has involved 
ongoing, extensive collaboration with city residents and stakeholders, internal 
city departments such as Public Works and Risk Management, and outside 
agencies like Clean Water Services. 
- Urban Forestry Code Revisions 
UFCR Citizens Advisory Committee 
Technica l Advisory Committee 
Peer Review 
Planning Commission 
City Council 
~ "' Urban Forestry Master Plan 
UFMP Citizens Advisory Committee 
Planning Commission 
City Council 
=====-==;:::::=;·- Comprehensive Plan 
Policy Interest Team/Tree Board 
Planning Commission 
City Council 
City of Tigard Urban Forestry Code Revisions I Volume I I 2 
2 
Overview of Key Elements 
To implement the project goals, the Urban Forestry Code Revisions project 
outcomes are presented in five major categories, the key elements of which 
are described below. 
Urban Forestry Standards for Development (Title 18) 
• 
• 
Requires all major developments to plant or preserve a certain 
amount of tree canopy to support goals for citywide tree canopy 
cover. The required tree canopy has been extensively tested and peer 
reviewed to ensure it is achievable and results in a reasonable balance 
between trees, open space and development. 
Tree canopy standards are tiered based on zoning. For example, 
development in low density residential areas will be required to have 
more tree canopy than in areas of dense zoning, such as downtown 
Tigard. 
Tree Grove Preservation Incentives (Title 18) 
• 
• 
Provides flexible standards and incentives to preserve large groves of 
primarily native trees during development. This includes options to 
have fewer housing units than the code would othe1wise require or 
increase housing units on one part of a property to preserve trees on 
another part. 
The city identified 70 large groves of prin1arily native trees covering 
527 acres that are eligible for the tree grove preservation incentives. 
All of the groves have been mapped and property owners have been 
contacted to raise awareness of the incentives consistent with 
statewide planning requirements. 
Tree Permit Requirements (Title 8) 
• 
• 
Consolidates existing tree permit requirements scattered throughout 
the code into the newly created Tigard Municipal Code Title 8 for 
ease of use. T he tree categories that will continue to be protected 
through a permit process include street trees, trees in sensitive lands, 
trees required with development, trees planted using the city's Urban 
Forestry Fund, and Heritage Trees. 
Streamlines the decision-making process without regulating 
additional tree situations. When the reasons for tree removal are 
simple (e.g. poor/ hazardous condition, damaging 
structures / infrastructure, etc.) the permitting process will be simple. 
City of Tigard Urban Forestry Code RcYisions I Volume 1 I 3 
" 
Tree Canopy-
The area above ground 
which is covered ry the 
trunk, branches and foliage 
of a tree or group of trees' 
crowns. 
" 
Definition, T igard Urban 
Forestry Code Revisions 
3 
W hen healthy trees are proposed for removal, the public will have an 
opportunity to comment without requiring an expensive and time 
consuming land use review. 
Hazard Trees (Title 8) 
• 
• 
Creates a process for resolving hazard tree issues in a more equitable, 
objective and efficient way. Willie neighbors are encouraged to work 
out their issues amicably, a third party arborist could be hired to 
provide an objective voice and a path towards resolution. 
The existing hazard tree process is unclear about the city's role in 
hazard tree issues. The recommended process clarifies the city's roles 
which no t only makes the process more efficient, but also has the 
result of limiting the city's legal exposure. 
Urban Forestry Manual 
• 
• 
T he Urban Fores try Manual is an essential element o f the project 
because it provides regulatory text in the form o f administrative rules 
that implement the code details in Title 18 and Title 8 described 
above. 
The Urban Forestry Manual documents most of the city's current 
administrative practices regarding tree planting, preserva tion and 
maintenance which provides certainty to users o f the code without 
making the code itself excessively long. 
City of TiganJ Urban hm:stry Code RcYisions I \ 'olumc I I 4 
Would you strongly support, support, 
oppose, or strongly oppose city 
regulations that would require that 
some trees be preserved and new 
ones planted on sites that are being 
developed? 
100% 
90% 
80% 
70% 
60% II • Strongly SO% 
• Support/ 
40% I K-* 1 
Oppose 
30% 
20% 
10% 
0% 
* Excerpted from a statistically valid 
survey of Tigard residents conducted as 
part of the 2009 Urban Forestry Master 
Plan. Full results are available in 
Appendix A of the Master Plan located in 
Volume V. 
4 
Organization of the Urban Forestry Code Revisions 
Documents 
The Urban Forestry Code Revisions project is presented in five volumes. 
Volume I provides the project overview and describes the process used to 
develop all of the elements. Volume II is the land use elements of the code, 
and Volume III the non land use elements. Volume IV contains the Urban 
Forestry Manual. Volume V contains technical reports and research that 
contributed to the code revisions along with details of the public input and 
deliberations to date. 
Volume I I Project Overview 
Project Overview includes the following sections: 
• 
• 
• 
Project Introduction 
Overview of Key E lements 
Key E lement Summaries 
• 
• 
• 
• 
• 
Urban Forestry Standards for Development 
Tree Grove Preservation Incentives 
Tree Permit Requirements 
Hazard Trees 
Urban Forestry Manual 
Appendix A includes additional detail about the information used to 
shape the Urban Forestry Code Revisions Project, and includes the 
following sections: 
• 
• 
• 
• 
Process summary 
Summary of Community Ideas and Concerns 
Summary of Planning Commission Deliberations 
Existing Conditions 
Volume II I Land Use Elements 
Community Development Code (Title 18) is the Planning 
Commission 's recommended draft of the D evelopment Code. This 
section includes commentary on the amendments. 
Peer Review demonstrates how the Planning Commission 's 
recommended draft of the Development Code and Urban Forestry 
Manual will work in application. 
ESEE Analysis is a report that addresses Statewide Planning Goal 5 
-Natural Resources requirements for the preservation of Significant 
Tree Groves. 
City o f Tigard Urban Forestry Code Re,•isions I Volume I I 5 
5 
Staff Report and findings includes the staff recommendation for 
approval o f the land use elements (Title 18 and the Comprehensive 
Plan Amendment) and the findings that demonstrate the land use 
elements meet the necessary approval criteria. 
Volume III I Non Land Use Elements 
Tigard Municipal Code is the staff proposed draft of the Municipal 
Code (Title 8 and o ther Municipal Code titles) . T his section includes 
commentary on the amendments. 
Volume IV I Urban Forestry Manual (Administrative Rules) 
Urban Forestry Manual consists o f administrative rules that 
implement the technical details o f the urban fores try related code 
provisions in Title 8, Title 18 and other applicable titles in the Tigard 
Municipal Code. 
Volume V I Additional Background Materials 
Planning Commission Deliberations details Planning Commission 
discussion and decisions during the public hearing process. 
Amendment Requests Document for the Planning Commission 
lists code amendment requests received in response to the first 
Planning Commission public hearing and staff responses. 
Outstanding Issues for the Urban Forestry Code Revisions 
includes additional information on the outstanding issues that were 
further deliberated by the Planning Commission before making their 
final recommendation to City Council on May 7, 2012. 
Log of Input lists the input received and any code changes from the 
last meeting of the CAC to the staff proposed draft o f the Urban 
Fores try Code Revisions to Planning Commission . 
CAC Guiding Principles includes the consensus view o f the 
Citizens Advisory Committee (CAC) developed to help guide the 
legislative adoption process . 
Tree Values includes information and current research on the 
environmental, economic, social and aes thetic benefits of trees . 
Canopy Standards explains the reasons for adopting tree canopy 
cover requirem ents as well as the methods used to arrive at the 
requirements . 
Soil volume details research about the soil volume required to 
support a mature tree canopy. 
Cit)· of 'l'iganl Urban l'orcstry Cock Rc,·isions I \'olumc I I (> 
6 
Tree Canopy Fee discusses research used to develop a square foot 
value for tree canopy. 
Regulatory Comparison is an excerpted report prepared by Metro 
and the Audubon Society that summarizes and compares regional 
urban forestry programs and regulations. 
Urban Forestry Master Plan is the City of Tigard's recommended 
plan for achieving the urban forestry goals in the Comprehensive 
Plan. 
City of Tigard Urban Forestry Code Rc,·isions I Volume I I 7 
7 
Key Element Summaries 
The following pages summarize the aspects o f the proposal that received the 
most attention throughout the Urban Fores try Code Revisions process. 
Below is a guide to the proposal summa1y: 
Land Use or Non Aspects Covered in 
Category Land Use Element Proposal Summary 
Urban Forestry Land Use • Tree Canopy Approach 
Standards for (Title 18) (page 9) 
Development • Tree Canopy 
Requirements (page 12) 
• Implementation: Urban 
Forestry Manual (page 
14) 
Tree Grove Land Use • Tree Grove Preservation 
Preservation Incentives (Title 18) Incentives (page 17) 
Hazard Trees Non Land Use • Resolution of Hazard 
(Title 8) Tree Situations (page 20) 
Tree Permit Non Land Use • Tree Removal Permits 
Requirements (Title 8) (page 23) 
• Heritage Tree and 
Significant Tree Program 
(page 22) 
Urban Forestry Manual Non Land Use • The Urban Forestry 
(Title 8 and Title 18) Manual consists of 
administrative rules that 
implement the details of 
the urban forestry 
related code provisions. 
(Page 25) 
A t the conclusion o f each section the loca tion o f additional information 
within the five volumes is provided. 
Ci tY of TigarJ Urban Fot-c>try Code RcYi>iom I \'olumc I I 8 
8 
Tree Canopy Approach 
Background 
The decision to shift Tigard's urban forestry 
standards for development to a tree canopy approach 
has been the subject of several community 
conversations, first at the Citizens Advisory 
Committee (CAC) and then at the Planning 
Commission. A more detailed summary of the tree 
canopy approach discussions can be found in the 
appendix to Volume I. 
The CAC's consensus recommendation was that the 
tree canopy approach, which requires development to 
achieve a certain percentage of tree canopy through 
planting or preservation, is the best way to address 
previously raised community concerns. 
During past planning processes, there was general 
agreement that the existing development code unfairly 
burdens property owners with existing trees and 
encourages the overplanting of replacement trees. 
The reasoning was that mitigation requirements apply 
only to property owners with existing trees over 12-
inch trunk diameter, and replacement trees or fees are 
required based on the diameter of trees removed. 
For example, if a 12-inch diameter tree is removed, 
replacement with 6, 2-inch diameter trees or a $1,500 
fee in lieu of replacement ($125/ inch fee) is required. 
While property owners without any trees get off 
"scot-free", property owners that have been stewards 
of their trees over the years could pay into the 
hundreds of thousands of dollars to make way for 
development. 
During the Urban Forestry Master Plan process, the 
community recommended addressing this equity issue 
as part of the development code revisions by creating 
" ... canopy cover .. . requirements for all lots to be 
met by either preserving existing trees or planting new 
trees". Council concurred during acceptance of the 
Master Plan. 
TREE CANOPY 
canopy 
spread 
Cross Section 
Definition 
canopy 
area 
Plan View (overhead) 
...... "Tree Canopy" - The area above ground which is 
covered by the trunk, branches and foliage of a tree 
or group of trees' crowns. 
This means that regardless of what a property looks 
like before development, a certain standard of tree 
canopy should be met after development is complete. 
While the Planning Commission supported the CAC 
consensus recommendation for a tree canopy 
approach, key changes were made to the proposal by 
the Planning Commission, in response to public 
input, which include: 
• Reducing the amount of tree canopy required for 
higher density residential development; 
• Allowing required tree canopy to be measured for 
the overall development site rather than individual 
lots for higher density residential development 
and non-residential development; and 
• Granting bonus credits for planting native trees. 
Additional details on the tree canopy approach can be 
found in the Canopy Standards memo in Volume V. 
9 
City of Tigard Urban Forestry Code Re,· isions I Volume I I 9 
Tree Canopy Approach 
Innovative Approach 
While the tree canopy approach is innovative, the 
CAC and Planning Commission were comfortable 
with being on the leading edge and felt it was right for 
T igard for three main reasons: 
• The canopy approach allows maximum flexibility 
for the project designer to meet code 
requirements. 
• T he canopy approach is more consistent with 
urban forest science and the city's long-term urban 
fores try goals. It encourages large stature, 
appropriately spaced trees, which have the highest 
benefit / cost ratios. 
• The canopy approach requires the project designer 
to consider future canopy growth, which helps 
ensure that trees are properly placed within a site 
to become long-term amenities. It encourages 
appropriate tree spacing and setbacks from 
buildings by highlighting mature canopy growth. 
The tree canopy approach has the added benefit of 
supporting the community's long term urban forestry 
goals to increase tree canopy citywide from the 
current amount of 24% to 32% by 2027, and 40% by 
2047. 
Tree Mitigation vs. Canopy Approach 
T he following two examples on page 12 demonstrate 
some o f the differences betvveen the tree mitiga tion 
approach in the current code and the tree canopy 
approach in the proposed code. In the current code, 
mitiga tion requirements o ften result in the planting of 
many, closely spaced trees. This is no t only 
incompatible with most people's landscape design 
preferences, but overcrowding of trees can be a 
detriment to long term tree health and stability. In the 
proposed code, tree canopy requirements ensure 
adequate spacing which accounts for the long term 
growth of trees while allowing for aesthetically 
pleasing landscape design . 
Peer Review 
Planning Commission 
~ Commissioners 
took a significant 
amount of time to 
receive public 
testimony and 
deliberate on the 
proposal. 
Staff and consultants ex tensively tes ted the tiered tree 
canopy requirements on a wide range o f development 
projects to ensure they are achievable, result in a 
reasonable balance between trees and development, 
and do no t force typical development pro jects to pay 
a fee in lieu of canopy or utilize the discretionary 
review option. 
The peer review results demonstrate that these goals 
have been met. T he Planning Conunission concurred 
after studying the peer review and discussing the 
results at length with staff and consultants during 
their public hearing process. The peer review can be 
found in Volume II. 
For More Information 
Canopy Standards Memo: Volume V 
Peer Review: Volume II 
Sun'lmary of Community Ideas and Concerns, Urban 
Fores try Standards for D evelopment: Volume I 
Planning Commission D eliberations: Volume I 
Urban Fores try Master Plan: Volume V 
Tree Canopy Fee Memo: Volume V 
Tree Values Memo: Volume V 
Portland Metro Area Regulatory Comparison Report: 
Volume V 
10 
City of Tigard Urban l;orcstry Code RcY isions I \'olumc I I J(J 
Tree Canopy Approach 
Tree Planting Plan- Current Code 
~.' ·--- . 
,• 
.·· 
.·· 
••)•· ,__,___ff 
,~·'· 
. ·· 
.·· 
Tree Planting Plan- Proposed Code 
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City of Tigard Urban l'orcstry Code Rc,· isions I Volume I I 11 
Benefits of the Proposed Code 
~ The first site plan shows how 
tree mitigation requirements in 
the existing code are met. Note 
that this plan includes Douglas-
firs planted 10 feet on center 
with up to 8 trees in the 
backyards of lots. This is 
incompatible with most people's 
landscape design preferences . 
~ The second site plan shows 
how proposed tree canopy 
requirements, which do account 
for the future growth of trees, 
with appropriate spacing and 
setbacks from buildings, could be 
met. The second site plan is also 
desirable because the design 
enhances street tree canopy, 
prove to have high 
environmental benefits and 
increase the value of 
surrounding real estate. 
11 
Tree Canopy Requirements 
Summary 
The Urban Fores try Standards for D evelopment 
represent the bigges t change from existing to 
proposed code. A shift in focus from development 
mitiga tion requirements to a tree canopy approach is 
a cornerstone o f the proposed code. 
Currently, tree planting and preserva tion requirements 
are determined by the number and trunk diam eter of 
existing trees on the site during land use review. So, if 
you have few trees to begin with, few trees will be 
required with development. 
In the Planning Commission's recommendation for 
Title 18, each development within the same zone 
starts with the same requirements, and these 
requirements are calculated using tree canopy. H ence, 
tl1e name "tree canopy approach." 
How it works 
~ Chapter 18.790: Urban Forestry Plan sets out 
effective tree canopy targets for the following 
types o f land use review: Conditional Use, 
D owntown D esign Review, Minor Land 
Partition, Planned D evelopmen t, Sensitive 
Lands Review, Site D evelopment Review, and 
Subdivisions. See Volume II for Chapter 
18.790. 
~ The Urban Forestry Manual sets specific tree 
canopy requirements based on zoning: 40%, 
33% or 25% effective canopy across the 
development. See Volume IV for the details 
on calculating percent tree canopy. 
~ D evelopers have four options they can 
combine to meet the effective tree canopy 
requirements: 
• 
• 
• 
Preserva tion 
Planting 
Fee in lieu 
• Discretionary Review 
~ In the proposal, preserva tion of exis ting trees 
receives 200% canopy credit to incentivize 
preserva tion . Planting o f native trees also 
receives bonus credits to encourage species 
which contribute to Tigard's sense of place. 
~ Bonding is required to ensure the 
es tablishment o f all newly planted trees which 
is consistent with the city's current practice. 
Meeting Canopy Targets ....,. 
In their guiding principles, the CAC set a preference fo r 
flexibility in meeting the tiered tree canopy 
requ irements. 
Preservation 
Trees in good condition, suitable for 
preservation and of appropriate 
species receive 200% credit based on 
their existing canopy area . 
Planting 
The calculated mature canopy area of 
all trees planted receive canopy 
credit, native trees receive credit for 
125% of their mature canopy area . 
Fee-in-Lieu 
A fee can be paid for planting or 
preserving trees elsewhere. 
Discretionary Review 
Innovative, alternate development 
proposals that provide equivalent 
environmental benefits (hydrological, 
climate or wildlife) can be used instead 
of planting or preserving trees. 
City of T igard Urban h >rc<try Code Rc,·i<ion< I \'olumc I I 12 12 
Tree Canopy Requirements 
Tiered Tree Canopy Requirements 
Tier 1 
Tier 2 
Effective tree canopy: 40% 
Actual onsite tree canopy: 16-40% 
Zones: Low and Medium Density Residential 
Effective tree canopy: 33% 
Actual onsite tree canopy: 13-33% 
Zones: Medium-High and High Density 
Residential; Neighborhood, Community, General, and 
Professional/ Administrative Commercial; Mixed-Use 
E mployment, Commercial, and Residential; and 
Industrial Park 
Tier 3 
Effective tree canopy: 25% 
Actual onsite tree canopy: 10-25% 
Zones: Mixed Use Central Business District, Mixed 
Use Comercial-1; Light and Heavy Industrial; and 
schools in all zones 
Tree Plan Requirements 
.... In the proposed code urban forestry plans will be 
required for development projects requiring higher 
levels of review (Type II or Ill) . Tree plan requirements 
are included in the Urban Forestry Manual. 
~ 
[] --
0'1. ...... _ -- - · - --·-.. ~2 ;.-~--~, h~ l Jill'- ilfll_~-
9fTE TREE CANCA"Y PLAH EOCEWOOO.., 2 
Effective vs. Actual Onsite Canopy 
The term effective tree canopy is used to distinguish 
the actual tree canopy that may be present within the 
lot lines of a particular development. To meet 
effective tree canopy requirements, the preservation 
of existing trees is granted 200% canopy credit, the 
planting of native trees is granted 125% canopy credit 
and planting of street trees is granted full canopy 
credit even though half of their canopies overhang 
streets, which are not part of the calculations. 
The end result is that even though a particular 
development may have a 40% effective tree canopy 
requirement, as little as 16% of the development may 
actually be covered in tree canopy. 
Mature Canopy Area 
~The expected canopy area 
fo r a list of common street 
trees, parking lot trees and 
native trees are included in the 
Urban Forestry Manual. 
For More information 
Urban Forestry Plan Requirements (Development 
Code, 18.790.030): Volume II 
Discretionary Urban Forestry Plan Review Option 
(Development Code, 18.790.040): Volume II 
Peer Review: Volume II 
Urban Forestry Plan Standards (Urban Forestry 
Manual, Section 10): Volume IV 
13 
City of Tigard Urban l 'orestry Code Revisions I Volume I I 13 
Implementation: Urban Forestry Manual 
Summary 
The Urban Fores try Manual, which can be found in 
Volume IV, consists of administrative rules that 
implement the details of the urban fores try related 
code provisions. Sections 10 through 13 o f the Urban 
Forestry Manual contain some of the more significant 
implementation details for the Urban Forestry 
Standards for D evelopment, such as Urban Fores try 
Plan requirem ents, T ree Canopy and Fee-In-Lieu 
calculations, and Soil Volume requirem ents. T he 
details for implementing the Urban Forestry 
Standards for D evelopment in Title 18 are described 
below. 
How it Works 
T he Urban Fores try Manual contains administrative 
rules that implement the details of the urban fores try 
related code provisions, and is organized into 13 
sections. Sections 1 through 9 address tree situations 
outside o f the land use process; hazard trees and 
street trees are examples. Sections 10 through 13 
include the Urban Forestry Standards for 
D evelopment, which are more fully described below: 
Section 10 of the Urban Fores try Manual specifies: 
~ Site plan requirements documenting: 
• T rees to be removed or prese1ved with 
development (Volume IV, Section 10, Part 1), 
and 
• The location, species, size and mature canopy 
o f trees to be planted (Volume IV, Section 10, 
Part 2). 
~ Arborist or landscape architect report 
requirements documenting: 
• D etailed information on each tree shown to 
be removed, planted or preserved on the site 
plans (Volume IV, Section 10, Part 3); 
• T he effective tree canopy cover; and 
• Tree canopy fee calculations (Volume IV, 
Section 10, Part 4). 
~ Significant tree grove preserva tion considerations 
(Volume IV, Section 10, Part 5). 
Section 11 o f the Urban Fores try Manual specifies 
implementation standards such as monitoring 
requirements during development. Sections 12 and 13 
detail soil volume standards for street and parking lo t 
trees. 
Calculations 
D etailed information about how to calculate effective 
tree canopy cover is in Section 10, Part 3.M of the 
Urban Forestry Manual. H ere are some of the 
highlights: 
• 
• 
• 
Tigard citizens favor native trees because they 
create a strong sense of place. Planting native 
trees is encouraged by applying their mature 
canopies at 125%. 
Tigard citizens value healthy mature trees 
because they are irreplaceable. Prese1vation o f 
healthy rna ture trees is encouraged by 
applying their exis ting canopies at 200% . 
Tigard citizens value street trees because leafy, 
tree lined streets help make Tigard "A Place 
to Call Home". Street trees are encouraged by 
granting full canopy credit even though the 
canopy may cover the street and no t the 
development. 
T hrough strategic site design and species selection, all 
three o f the options described above could be used to 
minimize the relative am ount o f tree canopy to open 
space and development if desired by the project 
applicant. 
14 
City of TiganJ Urban Forestry Code RcYisions I \'olumc I I 14 
Implementation: Urban Forestry Manual 
Fee in lieu 
Although the recommended code has been designed 
so that the tree canopy requirements are achievable 
on the typical range of development projects in 
Tigard, some property owners may just not want any 
trees on their lot. 
The CAC and Planning Commission included a fee in 
lieu mechanism to address this personal preference 
while recouping the value of tree canopy for use in 
tree planting, preservation and other urban forestry 
program activities elsewhere in the community. 
The tree canopy fee in lieu option is described in 
detail in the Tree Canopy Fee Memo in Volume V. 
The CAC and Planning Commission decided the tree 
canopy fee in lieu is a fair and reasonable proposal 
since it is based on the International Society of 
Arboriculture's tree appraisal m ethodology. In fact, 
the fee in the proposed code is lower than the fee in 
lieu in the existing code. 
Fee Comparison 
...- Tigard staff calculated the fee per caliper inch of 
several local jurisdictions as an approximation in order 
to establish a common unit for comparison. 
City Fee Per Caliper Inch 
City of Tigard (existing) $125 
City of Tigard (proposed) $87 
Beaverton $45 - $100 
Lake Oswego $164 
Oregon City $145 
Portland $300 
West Linn $87.50 
Wilsonville Market Price 
Vancouver, WA Market Price 
I 
I 
Soil Volumes 
Trees need soil to grow. In fact, there is a direct 
relationship between the amount of soil provided and 
the mature size of trees. 
The Urban Forestry Manual includes minimum soil 
volume standards for street trees and parking lot trees 
because these tree types are not typically provided 
adequate soil volumes. Council prioritized increasing 
tree canopy over streets and parking lots through the 
Urban Forestry Master Plan. The soil volume concept 
is described in the Soil Volume memo in Volume V. 
The details of calculating soil volumes for street trees 
are in Section 12 of the Urban Forestry Manual and 
for parking lot trees are in Section 13 of the Urban 
Forestry Manual in Volume IV. 
For street trees, soil volumes standards are tied to the 
width of the sidewalk. For parking lot u·ees, 1000 
cubic feet of soil volume is required per tree. In 
addition, parking lots are required to be designed to 
achieve 30% tree canopy cover at tree maturity. 
Minimum Soil 
Right of Way Volume 
Width Requirement 
(feet) (cubic feet per tree) 
Up to 10 400 
Over 10 up to 12 500 
Over 12 up to 14 600 
Over 14 up to 16 700 
Over 16 up to 18 800 
Over 18 up to 20 900 
Over20 1000 
Soil Volume Standards 
• For street trees, soil volumes standards are tied 
to the width of the sidewalk. 
City of Tigard Urban Fores try Code RcYisions I Volume I I 15 15 
Implementation: Urban Forestry Manual 
Structural Soils 
O n some development sites, there may not be enough 
room to provide open soil areas because more 
parking or paving is needed. In these cases, stmctural 
soils may be used under paving to provide trees with 
the soil volumes they need to grow 
PARKING LOT SURFACING 
PROFILE 
Structural Soils 
.... Appendix 17 of the Urban Forestry Manual includes 
example covered soil volume specifications and includes 
requirements for materials, placement, etc. 
Soil Volume· 500 cubtc feet 
Sotl Volume 120 cubtc feet 
3·1 3. 
For More Information 
Urban Forestry Plan Standards (Urban Fores try 
Manual, Section 10) Volume IV 
Urban Fores try Plan Implementation Standards 
(Urban Forestry Manual, Section 11): Volume IV 
Street T ree Soil Volume Standards (Urban Fores try 
Manual, Section 12): Volume IV 
Parking Lot Tree Canopy Standards (Urban Fores try 
Manual, Section 13): Volume IV 
Peer Review: Volume II 
Canopy Standards Memo: Volume V 
Soil Volume Memo: Volume V 
Tree Canopy Fee Memo: Volume V 
Soil Volume 1000 cubtc feet Size Potential 
~ There is a direct 
relationship between the 
amount of soil provided 
and the size potential of 
trees. So il volume 
standards are included in 
the proposal for street 
and parking lot trees. 
City oF Tigard Urban l :o r~stry Code ReY isions I \'olumc I I 16 16 
Tree Grove Preservation Incentives 
Summary 
T he Urban Forestry Mas ter Plan brought to light that 
while residents prioritize tree grove preservation, the 
city's large groves are disappearing. In eleven years, 
from 1996 to 2007, there was a 24% decline in large 
tree groves in Tigard . As such, council provided 
direction through the Urban Forestry Master Plan to, 
"Establish an incentive-based program to preserve 
Tigard 's rem aining groves of native trees." 
F lexible standards and incentives are allowed under 
the proposed code to facilitate the preservation of the 
city's rem aining tree groves. T hese standards and 
incentives were developed in compliance with 
statewide Goal 5 requirements and allow: 
• 
• 
• 
• 
• 
• 
• 
Waiver of minimum density requirements 
Oess units than otherwise requil:ed by code), 
D ensity transfer from the tree grove to the 
non-tree grove portion of a site, 
A ttached units, 
Flexible setbacks, 
Flexible lot sizes, 
Flexible street widths, and 
Increased building heights for commercial and 
industrial development. 
T he T ree G rove E SEE analysis in Volume II 
describes the significant tree grove designation 
process. Section 18.790.050.D o f the Tigard 
D evelopment Code in Volume II includes the flexible 
code standards and incentives . 
While 527 acres of tree groves are eligible, the 114 
acres of tree groves on the city's buildable lands 
inven tory are most likely to be developed and 
therefore utilize the flexible standards and incentives. 
All options are designed to increase flexibility and 
reduce costs for developers to prese1ve at least a 
portion of a tree grove. 
How it Works 
~ A map o f significant tree groves will be 
adopted into the Comprehensive Plan and 
maintained by the Community D evelopment 
Director. 
~ In order to qualify for these flexible standards 
find incentives a new development must: 
• Contain at least 10,000 square feet o f 
significant tree grove outside of 
protected sensitive lands, 
• Preserve at least 50% of tree grove 
onsite, and 
• Permanently protect the tree grove, 
such as by placing it in an open space 
tract. 
~ Project applicants will be required to work 
with a certified arborist or landscape architect 
to m aximize the connectivity and viability of 
the prese1v ed portion of a tree grove. Section 
10, Part 5 o f the Urban Forestry Manual in 
Volume IV includes Significant T ree G rove 
Preservation Considerations that will be used 
to guide which portion o f a tree grove to 
preserve. 
~ N eighborhood compatibility components 
have been included in the flexible standards 
and incentives. 
17 
City of Tigard Urban Forestry Code RcYisions I Volume I I 17 
Tree Grove Preservation Incentives 
Significant Tree..· C ron:~ 
City of TigarJ 
7Uj.!;run.·!" 
~2.7 acre~ ~ 
I ':S " ' 
' . . . . . ' 
kfHP\;'. 
c::J Sign1fiant Tru Grove 
S~gnllic.nt Htbll-at 
CJ r.garo City Boundaty 
Ta:dol Boondary 
i 1llh' 
Goal 5 ESEE Analysis 
To develop these new flexible standards and 
incentives, the city was required to follow the 
statewide Goal 5 requirements. T he city hired a 
consultant to inven tory Tigard 's tree groves, evaluate 
the economic, social, environment, and energy 
(ESEE) consequences of preserva tion, and to assist in 
collaborating with affected proper ty owners. 70 large 
groves of primarily native trees covering 527 acres 
have been deemed eligible for the flexible standards 
and incentives , including 114 acres within the city's 
buildable lands inventory. 
The city held two tree grove open houses: one during 
the inventory phase, and another later in the process 
to discuss the draft code standards and incentives for 
tree grove preservation . At the first open house tree 
grove property owners were somewhat concerned 
that the city was trying to limit their property rights. 
H owever, at the second open house they realized that 
Significant Tree 
Groves Map 
~ The city identified 
70 large groves of 
primarily native trees 
covering 527 acres, 
including 114 acres 
within the city's 
buildable lands 
inventory. This map 
will be adopted as part 
ofthe UFCR project. 
the flexible standards and incentives were designed to 
provide them with additional developn'lent options 
that they would no t o therwise have but for the 
presence of their tree groves . The Tree Grove ESEE 
Analysis in Volume II dem onstrates that the city's 
process o f developing the Tree G rove Preserva tion 
Incentives complies with statewide Goal 5 
requirem ents and reflects the local values o f the 
Tigard community. 
For More information 
Flexible Standards and Incentives for the Preservation 
of Significant Tree G roves (Development Code, 
18.790.050.D): Volume II 
Significant T ree G rove Preserva tion Considerations 
(Urban Fores try Manual, Section 10, Part 5): Volume 
IV 
Tree Grove ESEE Analysis: Volume II 
18 
Ci ty of Tigard Urban l;orestry Code Rc,·isions I Volume I I l H 
Tree Grove Preservation Incentives 
Tree Grove Preservation Example 
Option 1: Standard lot subdivision, no tree grove preserved 
Average Lot Size: 75-8500 sq. ft . 
Number of Units: 28 
Option 2: Standard lot subdivision, all tree grove preserved 
Average Lot Size: 75-8500 sq . ft. 
Number of Units: 15 
Minimum Density Waived 
Option 3: Standard and small lot subdivision, portion of tree grove preserved 
>-' 
.....,,..,. .......... ,.,. .. 
Average Lot Size : 75-8500 sq. ft . and 35-4500 sq . ft . 
Number of Units: 11 standard, 17 small lot 
28 Units Total 
City of Tigard Urban Forestry Code Re,·isions I Volume 1 I 19 
19 
Resolution of Hazard Tree Situations 
Summary 
It is important to recognize that trees are massive 
living organisms within the urban environment. Trees 
can sometimes quickly change from healthy 
specimens to weak, dead or unstable hazards to 
people or proper ty around them . In recognition of 
the risks posed by trees, during the Urban Forestry 
Master Plan process the community recommended 
and council accepted "develop[ing] a hazard tree 
identification and abatement program." 
T he Ci\ C followed through on this council directive 
noting in their guiding principles, "When managing 
the urban forest, sa fety shall be of primary 
importance, and clear code standards and procedures 
for addressing hazard trees creates the regulatory 
framework for minimizing tree risk." 
Hazard trees are prohibited in both the current and 
the proposed Tigard Municipal Code. Currently the 
definition of hazard tree is unclear and there is a lack 
o f understanding about what the city's role in disputes 
between priva te property owners should be. The 
proposed code provides clarity about what constitutes 
a hazard tree and sets forth a process for resolving 
disputes. The purpose, as defined in Chapter 8.06 of 
the Municipal Code in Volume II is to "protect the 
health, safety, and welfare of people within the City of 
Tigard by es tablishing standards and procedures for 
the identification, evaluation and abatement of hazard 
trees." The Hazard Tree Evaluation and Abatement 
Procedures are detailed in Section 1 o f the Urban 
Forestry Manual in Volume IV. 
How it Works 
~ The definition of "hazard tree" is now 
consistent with the standardized rating system 
developed by the International Society of 
Arboriculture. T his helps to remove 
subj ectivity during the hazard tree evaluation 
Currently, if there is a dispute between 
neighboring property owners regarding a 
potentially hazardous tree, the City does not 
get involved, and instead directs the 
neighbors to work out a solution through civil 
means. Would you strongly support, support, 
oppose, or strongly oppose the creation of a 
program where the city would become 
involved in disputes between neighbors 
regarding hazard trees? 
70% 
60% 
50% 
40% 
* Excerpted from a 
statistically valid 
survey of Tigard 
residents 
conducted as part 
of the 2009 Urban 
Forestry Master 
Plan . Full results 
are available in 
Appendix A of the 
Master Plan 
located in Volume 
V. 
30% 
• Strongly 
• somewhat 
20% 
10% 
0% 
Support Oppose 
process by using industry standard methods 
and terminology. 
~ W hen there are disputes between private 
property owners, the owners are required to 
present clear evidence that they tried to work 
the issue out themselves before involving the 
city. 
~ When the city does become involved, a third 
party arborist would be hired to conduct the 
evaluation in order to provide an objective 
voice while at the same time limiting the city's 
legal exposure. 
~ If the arborist does determine there is a 
hazard, abatem ent would be required 
according to a specified timeframe. 
In drafting these processes staff worked closely with 
the city's risk division and attorney. Both agree that 
the proposal creates an efficient and effective 
framework for addressing hazard trees while not 
unduly exposing the city to liability. 
20 
City of Tigard Urban Forc<try Code RcYi<iom I \'olumc I I 20 
Resolution of Hazard Tree Situations 
Abatement Procedures 
The H azard Tree Evaluation and Abatement 
Procedures include the options of 1) iriformal 
reconciliation between parties without city involvem ent; 
or 2) formal reconciliation where the claimant submits an 
application, provides information, and pays fees . The 
city documents informal reconciliation and ensures 
abatement and apportionment of costs by private 
property owners or through city action. 
As with the current code, if there is an eminent threat 
to public safety, the city has the authority to 
immediately abate the hazard instead of following the 
procedures described in Section 1 of the Urban 
Forestry Manual. 
Standing 
~ After discussion, the 
CAC reached consensus 
that individuals or 
organizations who can 
demonstrate their life, 
limb or property is at 
risk by a tree in 
question have the right 
to file a hazard tree 
dispute resolution 
application. This is 
intended to limit the 
concern that people 
could use the hazard 
tree process as a means 
of harassment or 
intimidation. 
Definition 
•rhe definition of hazard tree incorporates by 
reference the probability of failure, size of defective 
part and target area . 
For More information 
Tigard Municipal Code (Chapter 8.08): Volume III 
Hazard Tree Evaluation and Abatement Procedures 
(Urban Forestry Manual, Section 1): Volume IV 
City of Tigard Urban Forestry Code Revisions I \' olume I I 21 
21 
Heritage Tree and Significant Tree Program 
Summary 
Tigard 's Heritage Tree Program was es tablished in 
2005 to identify and raise public awareness of rare 
and / or exceptional trees due to their age, size, 
species, horticultural guality or historical importance. 
The H eritage Tree Program is voluntary, initiated by 
the owners o f the trees. 
Once approved by City Council, Heritage Trees 
becomes protected via deed restriction. In exchange, 
the property owners receive city assistance with tree 
maintenance, a plague, and recognition on the city 
map and website. 
Although the city has the capacity to designate up to 
two Heritage Trees per year, only four Heritage Trees 
have been designated since 2005. Some property 
owners have expressed concern about the deed 
res triction requirement as a reason for not applying 
for designation since they would lose flexibility for 
removing a Heritage Tree in the future. 
To address these concerns, the CAC recommended 
es tablishing two tracks for publicly recognizing 
landmark trees. The Heritage Tree track is consistent 
with the city's existing Heritage Tree Program while 
the Significant T ree track provides for public 
recognition without the associated protections from 
removal. T hese tracks are detailed in Chapter 8.1 8 of 
the Tigard Municipal Code in Volume II. 
Monkey-Puzzle 
Tree 
~ This significant 
tree, Araucaria 
araucana, is located 
at SW 103'd in 
Tigard . 
How it Works 
A two track designation sys tem is proposed for 
publicly recognizing trees. 
~ T he Heritage Tree track provides city 
assistance for maintenance in exchange for 
regulatory protection. 
~ T he Significant T ree track allows trees to be 
publicly recognized without regulatory 
res trictions. Significant T rees would not be 
eligible for city assistance for maintenance 
since the property owner could choose to 
remove the tree at any time. 
For More Information 
Tigard Municipal Code (Chapter 8.18): Volume III 
City of Tigard Urban Forestry Code RcYisions I \'olumc I I 22 
22 
Tree Removal Permits 
Proposal Summary 
The following categories of trees are currendy 
regulated by the city: 
• Street and median trees, 
Trees in sensitive lands, 
wrong with the tree itself, but benefits such as views, 
solar access or a landscape redesign outweigh the 
benefits provided by the tree. The discretionary track 
would allow the public an opportunity to comment 
without requiring an expensive and time consuming 
land use review often required by existing code. 
• 
• 
• 
• 
Trees that were required with development, 
Trees that were planted using the Urban 
Forestry Fund, and 
Heritage trees . 
The group agreed not to expand the regulations to 
additional categories of trees. 
For More Information 
Tree Permit Procedures (Tigard Municipal Code, 
8.04): Volume III, p. xx 
In the proposed Tide 8, these categories of trees will 
continue to be regulated, with no expansion of 
regulations to additional categories. T he most notable 
change in this topic area is the creation of a 
consolidated permit system to make the permitting 
process clear, consistent and user friendly. 
Tree Removal Requirements (Tigard Municipal Code 
Chapter 8.10 - 8.16): Volume III, p . xx 
The CAC agreed that a consolidated permit system to 
address these protected categories of trees would 
make the permitting process more efficient. The 
group favored a dual track approach with automatic 
approval through a no- or low-fee process for trees 
that are in poor or hazardous condition, damaging 
property or preventing allowed development. A 
discretionary track would allow more unique 
situations to be addressed, when there is nothing 
Tree Removal Approval Criteria (Urban Forestry 
Manual Sections 3-9): Volume IV, p. xx 
Tree Permit Comparison 
Tiga rd current ly req ui res tree removal permits 
for t he categories of t rees listed below. The CAC 
desi red t he new code to consolidate the 
permitting process t o make it clearer, consistent 
and user fr iendly . ...,.. 
Permit Required In 
Proposed Current 
Tree Category Code Code Issues with current code 
Street and • No criteria, so removal is always approved . 0 0 
median trees 
Sensitive lands • Currently approval based on erosion, which is difficult to quantify, so 
0 0 
permits are almost always approved. 
• The current fee is nearly $300, which is a significant cost for a 
process with limited community benefit. 
Required with • To remove a tree required with development, the original land use 
development 0 0 permit would need to be modified. This is significantly costly and 
time consuming. 
Urban Forestry • Developing and tracking separate written agreements for each 
Fund 0 D planting project is an administrative challenge. 
Heritage Trees • Heritage Trees are approved by Council and may only be removed if 0 0 Council agrees or if they die. 
~ 
---- ------ --- -- ----- -------· ---- ·--
City of Tigard Urban Forestry Code Re,-isions I Volume I I 23 
I 
i 
I 
23 
Tree Removal Permits 
How it Works 
~ Proposed Tigard Municipal Code Chapter 
8.04 in Volume II es tablishes a framework for 
all tree permit decisions. 
~ Permits can be approved by way o f two 
processes: either a staff process for simple 
situations or a city board or committee for 
more complex situations. 
~ Replacement is required through planting or a 
fee in lieu when pro tected trees (except 
heritage trees) are rem oved. 
~ T he approval criteria for removing each o f the 
pro tected ca tegories o f trees can be found in 
the Urban Fores try Manual: 
o Street and median trees (Section 3 and 
Section 5) 
o Trees in sensitive lands (Section 6) 
o Trees that were required with 
development (Section 7) 
o Trees that were planted using the 
Urban Forestry Fund (Section 8) 
o H eritage Trees (section 9) 
Trees on City Property 
The Citizen's Advisory Committee 
didn't continue current code into 
proposal, voting to remove the "Trees 
on City Property" section in favor of 
consistent regulations that applied to 
all properties in Tigard, regardless of 
ownership. 
~ Early Morning Light 
By Paul August 
Is a tree permit required? 
Street and median trees 
Trees in sensitive lands 
Trees required with 
development 
Trees planted using the 
Urban Forestry Fund 
Heritage trees 
All other situations 
What type of permit is required? 
Simple 
For example, trees: 
• In poor or hazardous 
condition 
• Considered a nuisance 
• Damaging structures 
or infrastructure 
• Preventing allowed 
development 
What is the process? 
Simple 
City staff review based 
on approval criteria 
listed in the Urban 
Forestry Manual 
Complex 
For example, trees: 
• Blocking views or solar 
access 
• Not desirable due to 
species or personal 
preferences such as 
aesthetics or location 
Complex 
City board or 
commission uses 
discretion to weigh tree 
benefits and reasons for 
removal 
24 
City of Tigard Urban l'orcstry Code RcYisions I Volume I I 24 
Urban Forestry Manual 
Summary 
The Urban Forestry Manual in Volume IV consists of 
administrative rules that implement the details of the 
urban forestry related code provisions in Title 8, Title 
18 and other applicable titles in the Tigard Municipal 
Code. 
manual rather than in the code. Also when 
administrative changes are required such as adding or 
subtracting trees from the tree lists, the amendment 
process for administrative rules is more efficient while 
at the same time providing for adequate public notice 
and the opportunity for public participation. 
How it Works These administrative rules were developed for the 
Urban Forestry Code Revisions project to document 
m ost o f the city's current administrative practices 
regarding tree planting, preservation and maintenance 
without making the code excessively long. For 
example, administrative items such as planting 
specifications, tree lists and methods for calculating 
tree canopy are more appropriate in an adrni.lusu·ative 
~ Once authorized by council, the city manager 
may create and amend administrative rules 
according to the public process detailed in 
Chapter 2.04 of the Tigard Municipal Code. 
Topics 
Urban Forestry Manual 
Code Title 
Section Description Implemented 
1 Hazard Tree Evaluation and Abatement Procedures (creates a process for the reconciliation Title 8 
of hazard tree disputes between neighboring property owners) 
2 Street Tree Planting and Maintenance Standards (creates a process for property owners to Title 8 
plant and maintain trees along streets) 
3 Street Tree Removal Standards (creates a process for property owners to remove trees along Title 8 
streets) 
4 Median Tree Planting and Maintenance Standards (creates a process for the city to plant Title 8 
trees in center landscape medians within streets) 
5 Median Tree Removal Standards (creates a process for the city to remove trees in center Title 8 
landscape medians within streets) 
6 Sensitive Lands Tree Removal and Replacement Standards (creates a process for property Title 8 
owners to remove and replace trees within sensitive lands) 
7 Development Tree Removal and Replacement Standards (creates a process for property Title 8 
owners to remove and replace trees that were required with development) 
8 Urban Forestry Fund Tree Removal and Replacement Standards (creates a process for Title 8 
property owners to remove and replace trees that were planted using the Urban Forestry 
Fund) 
9 Heritage Tree Designation and Removal Standards (creates a process for designating and Title 8 
removing both Heritage Trees and Significant Trees) 
10 Urban Forestry Plan Standards (includes plan submittal standards and methods for Title 18 
calculating tree canopy cover for development) 
11 Urban Forestry Plan Implementation Standards (includes requirements for monitoring trees Title 18 
during the development process) 
12 Street Tree Soil Volume Standards (includes specifications for providing street trees Title 18 
adequate soil volumes) 
13 Parking Lot Tree Canopy Standards (includes specifications for ach ieving 30% tree canopy for Title 18 
parking lots and for provid ing parking lot trees adequate soil volumes) 
City of Tigard Urban Forestry Code Revisions I Volume I I 25 25 
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Process Summary 
T his section describes the planning process and public involvement efforts to date as part o f the development of 
the Urban Forestry Code Revisions proposal. T he public process kicked off in June 2010 and continues through the 
City Council adoption process 
Citizens Advisory Committee 
Tigard City Council appointed a Citizens Advisory Committee (CAC) containing a 
broad range o f community interes ts to advise city staff and seek consensus solutions 
during the code revisions process. Council recognized the importance of a citizen 
group for this process as the issues related to the health of the urban fores t crosses 
over a diverse range of interes ts and would benefit from thoughtful consideration 
by individuals representing those interes ts. 
The CAC m et 11 times between June 2010 and September 2011, and was 
professionally facilitated by JLA Public Involvement. T he 11 -m ember committee 
included community members appointed by council and representing a broad 
spectrum of interests and expertise. In J anuary 2011 , the CAC meeting schedule was 
~ ... _ i.' ., 
I 
- - u• k ~ ...... ~- . 
,._ ....... .... -
"'" . ~~ 
...... J¥t:_ • ~. - ·-=--
._ ~-
Figure 1: CAC and Planning 
Commission member Don Schmidt 
with his family at the first Tree G rove 
open house 
expanded to include additional and longer meetings to ensure the committee had ample time to discuss the project's 
topics. Community representation included members o f existing city boards and committees: T he Planning 
Commission, Parks and Recreation Advisory Board, and Tree Board. The committee also contained two m embers 
from the development community, including a H omebuilders Association representative, and single representatives 
from the environmental community, arborist profession , and citizens at-large. 
Morgan Holen , Certified Arborist and CAC m ember, said, "The city has done a great job o f responding to citizen 
input, and the draft code represents a balance of the various viewpoints heard throughout the process." The guiding 
principles presented in Volume V of this document represent the culmination o f the CAC's work on this project. 
Technical Advisory Committee 
T he Technical Advisory Committee (TAC) was comprised of city staff and agency representatives. I t also advised 
staff throughout the development o f the code. Internal city staff from several departments participated including 
Finance (Capital Improvement Program), E ngineering, D evelopment Services, Parks, Streets, Wastewater / Storm, 
Information Technology/ Geographic Information Services, Permit Coordination, Building, Current Planning and 
Long Range Planning. External agency representatives included Clean Water Services and the Oregon D epartment 
o f Transportation . 
In to tal, the 20-member committee met 14 times between June 2010 and November 2011. The group's purpose was 
to provide recommendations to staff based upon technical knowledge and familiarity with urban fores try issues . In 
general, the T AC m eeting schedule and agendas were similar to that of the CAC. The log of input in Volume V 
includes the technical input provided by the T AC, and comments o f the CAC and public during the technical 
review phase. 
27 
City of T igard Urban Forestry Code Revisions I Volume 1 I 27 
Public Involvement 
A public involvement plan for the Urban Forestry Code Revisions project was approved by the city's Committee 
for Citizen Involvement in May 2010. This plan addressed how the public involvement for the Urban Fores try 
Code Revisions would meet the city's Comprehensive Plan goals for oppor~nities for stakeholders to participate, 
communicate, and receive information about the project. This plan states that 
communication on the project will be guided by the following set o f priorities: 
• E mploy multiple communication channels to ensure we are able to reach a 
broad audience. 
• Keep city policy makers up-to-speed on the pro ject 
• The task is to manage conflict, not resolve it. 
T he theme of the initial messaging and outreach was that progress would result 
from improvements rather than solutions. A staff level communications team 
composed of the project manager and public involvement lead met regularly 
throughout the process to ensure the Public Involvem ent Plan was followed. 
Significant outreach efforts are described below. 
Two open houses on the tree grove prese1vation incentives and one on the entire 
~ ...... -.-. .......... -.. .. ,._ .. .__ 
'-·-·--4 ..... - .............. - . .---
___ .. __ .......... ____ ._ ......... 
<o..-, o • • ,......__n_,_ --·-....... - .. ~--
~ .... ""'- ~· - · ....... _ 
Figure 2: Pro ject new,dcttcr,; were 
,;enr by email and po,;ted on the 
project web,;ite. 
proposed code were held during the process. Conunents collected at each open house helped to shape the proposal 
presented to the Planning Commission 
A project newsletter was sent to interes ted parties by email fifteen times between July 2010 and May 2012. T his 
newsletter fea tured pro ject highlights, local tree information and ways for the community to be involved in the 
process . 
Public comment was invited via em ail and at the beginning of every CAC m eeting. T his information was shared 
with bo th the pro ject management team and the TAC for consideration. 
Outside events attended by pro ject staff where project information was disseminated included the Balloon 
Festival, CPO 4B m eeting, and the Tigard Area Farmers Market. 
T he city's website was regularly updated throughout the process with project information . Specific Web tools 
using G IS were developed to help residents and property owners identify tree groves and trees which may be 
subject to permitting on their property. 
The city's Cityscape newsletter was regularly used to announce updates about the Urban Forestry Code Revisions 
Projec t. Seventeen articles appeared between April 2010 and June 2012. 
A summary of community ideas and concerns gathered throughout this process is covered in the following section . 
Planning Commission Outreach 
Briefings for the Planning Commission on the Urban Fores try Code Revisions project efforts began in early 2010 
and continued through fall 2012. T he commission received a comprehensive briefing from Community 
D evelopment department staff on the Staff Proposed Draft Urban Fores try Code Revisions on January 9, 2012. 
The purpose o f the briefing was to provide an overview o f the planning process, draft code amendments and those 
aspects o f the code that received the mos t attention in order to prepare the Planning Commission for their public 
hearings . 
28 
City of Tiga n.l Urban Fo n:> try Code Rc,·i,; ions I \'olumc I I 2H 
City Council Outreach 
After directing staff to undertake the Urban Forestry Code Revisions process in February 2010 City Council 
remained engaged in the process through regular staff updates. 
Summary of Community Ideas and Concerns 
A wide range of stakeholders, including conununity groups, developers and staff, identified concerns about the 
city's current urban forestry regulations. This section summarizes the conununity's ideas and concerns that were 
addressed by the Citizen Advisory Committee on each of the urban forestry topics / code categories. 
Urban Forestry Standards for Development 
The city currently regulates trees during development through chapter 18.790, which requires tree protection, 
removal, and replacement plans. Chapter 18.7 45 also includes requirements for street trees, parking lot trees, and 
trees as buffers between differing uses. 
Chapter 18.790 
The major issues identified with the current tree plan requil:ements in chapter 18.790 are: 
• The mitigation standards encourage overplanting since trees are replaced on an "inch for inch" basis rather 
than "tree for tree" . 
• Since mitigation standards are only applicable to trees over 12-inch diameter, the incentive is to retain larger 
trees, which are less likely to sU1vive development ilnpacts. 
• Tree plan requirements only apply to sites with existing trees. Property owners with trees are penalized 
while property owners without trees are not. 
• Tree plan requirements are only applicable to trees on site at or near the time of development. This 
i11eentivizes the removal of trees in advance of development to avoid tree plan requirements and mitigation. 
• People often want to modify their tree plans during the course of development when they find there are 
conflicts between trees and buildings, roads, or infrastructure. However, the modification process is time 
consumi11g and cost prohibitive. This creates another incentive to remove all trees before development 
rather than risk conflicts with trees duri11g the course of development. 
The Citizen A dvisory Committee consensus was that applying a tree canopy standard, which requires development 
to achieve a set percentage of tree canopy through planting or preservation, is the best way to address these issues. 
A tree canopy standard will not encourage overplanting because it is based on the mature growth of the trees rather 
than number of trees. It will not incentivize the prese1vation of inappropriate u·ees because the project designer will 
not be penalized for tree removal, as long as they replant. The committee reconunended a bonus credit for 
preservation, which elimi11ates the incentive to remove trees in advance of development. 
Since a tree canopy standard is unlikely to fit every future development scenario, the committee agreed there should 
be a tree canopy fee in lieu option and a discretionary review option when planting and preservation are not 
possible or are undesired. The committee also agreed there should be a low cost and user friendly process for 
modifying trees plans for adaptation to unforeseen circumstances duri11g development. The committee addressed 
post-development tree issues in their discussion o f tree permit requirements. 
29 
Ci ty of Tigard Urban Forestry Code ReYisions I Volume I I 29 
The conunittee's major issues of debate were whether the city should require a base level of preservation, whether 
the percent o f tree canopy required was reasonable, and whether the tree canopy standard should be applied to 
additional development scenarios. 
In the end, the group decided that requiring a base level o f preservation would have the effect of limiting options 
for people with existing trees compared to people without trees. T his type of inequity is what the committee was 
striving to m ove away from . 
For the tree canopy requirement, the group initially studied a blanket 40% tree canopy requirement for all 
development citywide for consistency with the long term citywide tree canopy goal in the urban fores try mas ter 
plan. However, after further discussion there was agreement that the development code was no t going to be the 
sole method for meeting the 40% citywide tree canopy goal, and the committee decided it was important to set 
achievable tree canopy requirements that were tiered based on each zoning district and the typical development 
types found in each zone. 
T he committee considered applying the standards to additional development pernuts such as grading permits, 
building additions, and dem olition permits. H owever, after reviewing pas t projects the group agreed tree removal 
for these types o f smaller scale projects was no t a significant issue and it was no t necessary to apply additional 
regulations. The committee agreed that larger projects in sensitive lands should be required to meet additional 
standards since tree removal in sensitive lands has been a significant commmuty issue in the pas t. 
Chapter 18.7 45 
The major issues identified with the current tree planting requirements in chapter 18.745 are: 
• Trees planted to meet the landscaping requirements in chapter 18.745, are no t eligible for mitiga tion credit. 
T lus contributes to poor design and the overplanting of sites. 
• Parking lo t and street tree standards do no t include industty accepted soil volume requirements. This 
contributes to high failure rates and pavem ent damage due to lack o f space for roots. 
• There is no bonding requirement to ensure the es tablishment o f newly planted trees. 
The Citizen .Advisoty Conunittee reached consensus that trees planted to meet the standards in chapter 18.745 
should receive full credit towards the tree canopy cover requirements. T his allows flexibility in design and avoids 
overplanting o f sites. The group also agreed to require bonding to ensure the establishment of all newly planted 
trees . 
Due to cost concerns, the group was initially split as to whether there should be mininmm soil volume standards for 
parking lo t trees and street trees . H owever, the group decided there was enough flexibility in the draft development 
standards such as reduced parking and increased planting strip size to ensure trees could meet the requirements 
without more costly methods such as structural soil installation . 
30 
City of Tigard Urban l;ore, try Code ReYi,iom I \'olumc I I 30 
Tree Grove Preservation Incentives 
Based on community input, council directed staff to develop new flexible and 
incentive based code standards for the preservation of Tigard's remaining groves of 
native trees. 
To develop these new standards, the city was required to follow the statewide Goal 
5 requirements which involve inventorying tree groves, evaluating the economic, 
social, environment, and energy (ESEE) consequences of preservation, and 
involving affected property owners. 
The city identified 70 large groves of native trees covering 527 acres, including 114 
acres within the city's buildable lands inventory. 
Figure 3: Held in February 2011 , the 
second tree grove open house 
included a presentation from staff 
The Citizen Advis01y Committee agreed to a wide range of flexible standards and incentives for tree grove 
preservation through staff level reviews. Among them are a waiver of minimum density requirements, density 
transfer from the tree grove to the non-tree grove portion of a site, attached units, flexible setbacks, flexible lot 
sizes, flexible street widths, and increased building heights for commercial and industrial development. 
In exchange for these flexible standards and incentives, the committee agreed that the remaining portions of the 
groves should be permanently preserved through instruments such as open space tracts or dedication to the city. 
The group was initially split on whether to allow more intense multi-family residential development in single family 
zones for tree grove preservation, but later reached consensus not to allow it because of compatibility issues. 
The group was also initially split as to whether tree removal permits or mitigation should be required for tree 
groves, but later agreed this would be inconsistent with an incentive-based program. They also thought it could 
increase tree grove removal from people trying to avoid regulations in advance of adoption of the proposed code. 
Finally, the committee requested that staff investigate a tree canopy transfer system whereby excess preservation in 
one development could be transferred to a subsequent development. After researching the issue, staff 
recommended against developing such a system because of the equity issue involved with exempting one 
neighborhood from tree canopy standards due to excess preservation in another neighborhood. Also, the staff time 
associated with developing and maintaining a transfer system may not be justified given the limited amount of tree 
groves within buildable lands and uncertainty with the effectiveness of such a system. 
Hazard Trees 
The city currently prohibits hazard trees within the city limits of Tigard. However, the definition of what 
constitutes a hazard tree is unclear and there is a lack of understanding about what the city's role should be when 
there are disputes over hazard trees between private property owners. 
The committee agreed the city should define hazard trees according to the International Society of Arboriculture 
standard and continue to prohibit hazard trees in Tigard. When there is a hazard tree dispute between private 
property owners, the committee consensus was that the parties should be encouraged to work out the issues 
themselves and involve the city only as a last resort. When the city does become involved, a third-party arborist 
should be retained and the city should recover any costs incurred as a result of the dispute. 
The main issue for the committee involved who should have standing to file hazard tree claims with the city. The 
committee reached consensus that only people that can demonstrate their life, limb, or property is at risk by a tree 
Ci ty of Tigard Urban Fores try Code ReYisions I Volume 1 I 31 
31 
in question has the right to file a claim. T his is intended to limit the concern that people could use the hazard tree 
process as a means of intimidation whether or not a real threat exists . 
Tree Permit Requirements 
Certain categories of trees are currently pro tected by the city. Tree removal permits are required for trees in 
sensitive lands and street trees. Trees that were required to be planted or preserved with development can only be 
removed by modifying the original land use permit. Heritage Trees are designated by council, and can be removed 
if approved by council. T rees planted using the Urban Fores try Fund are protected through written agreements 
with every planting project. 
T he main issues with the current tree permit requirements include: 
• The approval criteria for tree removal in sensitive lands are based on erosion control, which is difficult to 
quantify, so permits are almost always approved. 
• The fee for sensitive lands tree removal permits is nearly $300, which is a significant cost for a process with 
linuted commuruty benefit. 
• There are no approval criteria for street tree removal, so rem oval is always approved. 
• The process for removing and / or redesigrung trees that were required with development is cost prohibitive. 
It involves modifying the original land use permit which costs thousands of dollars. 
• The heritage tree process limits participation because of the pro tections against rem oving designated trees . 
• D eveloping and tracking separate written agreements for planting projects fund ed by the Urban Forestry 
Fund is an administrative challenge. 
T he Citizen Advisory Committee agreed that a consolidated permit system to address these protected categories o f 
trees would make the permitting process more clear, consistent and user friendly. The group favored a dual track 
approach with automatic approval through a no- or low-fee process for trees that are in poor or hazardous 
condition, damaging property or preventing allowed development. A discretionary track would allow more uruque 
situations to be addressed, when there is no thing wrong with the tree itself, but benefits such as views, solar access 
or a landscape redesign outweigh the benefits provided by the tree. 
The group agreed no t to regulate any additional tree situations, but they did support creating a new, voluntary 
"sigrlificant tree" process to recognize important trees without the protections and res trictions associated with 
H eritage T rees . 
The committee was initially split as to whether permits should be required for the removal o f dead and hazardous 
trees that fall within one of the pro tected categories (s treet trees, sensitive lands tree, etc.). The final consensus was 
to require permits so there is adequate documentation to limit disputes between neighbors, and to ensure 
replacement trees are planted. 
They also debated whether dead trees, such as those in natural areas, should be required to be retained for wildlife 
purposes . The consensus decision was no t to prevent dead tree removal because the cos ts associated with tree 
removal will naturally result in their preservation. H owever, the group did agree that dead trees (that are no t 
hazards) should no t be prohibited in Tigard as they are in the current code. 
Finally, the committee discussed requiring permits for removing over a certain number o f unpro tected trees per year 
to limit clear cutting in advance o f development. The group reached consensus no t to require permits because the 
new standards for development do no t incentivize pre-development clearing. 
32 
City of T igard Urban l'orcstrl' Code Rc,-isions I \ 'olumc I I ."12 
Use of Existing Tree Mitigation Funds 
T he city has collected over $1 million in tree mitiga tion fees from applicants that did not replace trees that were 
removed with development. T hese funds are used by the city to plant trees on public property and along streets. 
The city's practice has been to use the funds for new tree planting and three years of early es tablishment only. 
T he Citizen Advisory Committee discussed whether the use of tree mitigation funds should be expanded to 
additional item s such as preserva tion o f existing trees, long term maintenance, education and outreach, and 
planning. While the committee was initially split on the issue, they did reach consensus that the city should 
continue to res tt·ict the use o f current tree mitigation funds to planting and three years o f early es tablishment. T heir 
rationale was the development community paid fees with the expectation that the fund s would be used for planting 
trees, and that using those fund s for expanded purposes would be inconsistent with that real or perceived 
commitment. H owever, d1e committee did agree that the revised code should allow for future funds collected to be 
used for a broader range o f urban forestry activities. 
T he committee's recommendation was subsequendy endorsed by the Tree Board and forwarded to council. In May 
2011 , council adopted Resolution 11 -16 clarifying that the newly named "Urban Forestry Fund" shall be used for an 
itemized list of activities required for tree planting and 3 years o f early es tablishment. 
For a final summary of the CAC's decisions, see their guiding principles in Volume V. 
Summary of Planning Commission 
Deliberations 
This section provides a brief summary of the Planning Commission's deliberations which led to their decision to 
unanimously recommend Council approval of the Urban Forestry Code Revisions on May 7, 2012. A detailed 
summary o f their deliberations can be found in Urban Forestry Code Revisions Volume V. 
During the Planning Commission portion o f the legislative adoption process, the urban fores tt-y code revisions were 
considered as four separate yet interconnected elements: 1) T he significant tree groves map which was the subject 
of the comprehensive plan amendment, 2) amendments to the land use regulations in Tide 18 which were the 
subject of the proposed development code amendments, 3) amendments to the non-land use regulations in all o ther 
tides except Tide 18 which were not part of the commission recommendation to council, and 4) administrative rules 
in the Urban Fores t:1-y Manual which were also non-land use regulations and therefore not part of the commission 's 
recommendation to council. 
In order to provide for a comprehensive view, Planning Commission reviewed, took tes timony, deliberated, and 
commented on both the land use elements and non-land use elements in the urban fores tt-y code revisions. 
H owever, the Planning Commission 's recommendation to Council was limited to the land use elem ents of the 
proposal which are the comprehensive plan am endmen t incorporating the significant tree groves m ap and 
development code amendments to Tide 18. 
T he Planning Commission held one workshop and four public hearings on the Staff Proposed Draft Urban 
Forestry Code Revisions from J anua1-y 2012 d1rough May 2012. Although they received a range of public tes timony 
from a variety of people during their public hearing process (see Urban Forestt-y Code Revisions Volume V), the 
commission 's deliberations focused on two major themes: 
33 
City of Tigard Urban Forestry Code Rc,· isions I Volume I I 33 
1. E nsuring the tree canopy requirements appropriately balance the amount of trees, development and open 
space; and 
2. E nsuring the Urban Fores try Code Revisions do no t result in an excessive increase in cos ts for 
development. 
T heir deliberations and decisions on both themes are summarized below. 
Theme 1: Ensuring the tree canopy requirements appropriately balance the amount of trees, 
development and open space. 
Deliberations on Theme 1: T he Planning Commission discussed whether the tree canopy requirements, which 
consist o f three tiers based on zoning district intensity, will result in an appropriate balance between the amount o f 
trees, development and open space. They also discussed whether there would be excessive shading as required trees 
mature over time. 
T he conunission used the results o f the peer review, where the tree canopy requirements were tes ted on actual 
development projects, to inform their deliberations. Based on the peer review results, the commission felt generally 
comfortable with the resulting balance between trees, development and open space. H owever, they did decide to 
move the R-12 district from Tier I, which requires the highest percent canopy cover, into Tier 2. T his was because 
the R-12 district was no t tes ted as part o f the peer review phase, but the higher density residential districts (R-25 and 
R-40) were able to meet the Tier 2 requirements. 
In addition, to increase flexibility the Commission decided to reduce the minimum amount o f tree canopy required 
per lo t from 20% down to 15% in Tier 1, which contains the lower density residential districts and to eliminate the 
per lo t minimum requirement in Tiers 2 and 3, which include all o ther districts. This change to Tier 2 and 3also 
resulted in effectively lowering the tree canopy requirements by allowing the requirements to be met based on the 
overall development site, rather than on a lo t by lo t basis. 
The conunission recognized that the dra ft code includes a number o f options for decreasing the relative amount o f 
trees to development and open space. These options include granting 200% credit for preserving existing trees, and 
granting full credit for street trees even though half of their canopies overhang streets, which are no t part o f the lo t 
area calculations. T he conunissionnoted that there is also a discretionary review option that allows green building 
or development techniques instead of trees and an option to provide a fee in lieu o f tree canopy. 
In addition, the commission included one more option to decrease the relative amount o f trees compared to 
development and open space by granting 125% credit for the planting o f native trees . 
Commission Decisions on Theme 1: T he comtnission decided that in most cases the tree canopy requirements 
provide a reasonable balance between trees, development and open space. H owever, to be conserva tive, the 
commission moved the R-12 district into the Tier 2 category. 
City o f'l'iganJ Urban l:o re,try Code Rc,-i, ion' I \ 'o lume I I 3-1 
3-+ 
In addition, the commission decided to effectively lower the tree canopy requu:ements by 20 percent for the use of 
native trees by giving 125% canopy credit: 
Tree Canopy Requirements Tree Canopy Requirements 
without Native Trees with Native Trees 
Tier 1: 16-40% actual canopy on site Tier 1: 16-32% actual canopy on site 
Tier 2: 13-33% actual canopy on site Tier 2: 13-26% actual canopy on site 
Tier 3: 10-25% actual canopy on site Tier 3: 10-20% actual canopy on site 
· · · -
Finally, to increase flexibility the commission decided to reduce the per lo t minimum from 20% down to 15% for 
Tier 1 sites, and to eliminate the per lo t millimum for Tier 2 and 3 sites. 
Theme 2: Ensuring the Urban Forestry Code Revisions do not result in an excessive increase in costs 
for development 
D eliberations on Theme 2: T he commission discussed whether the Urban Forestry Code Revisions would result 
in an excessive increase in costs for development. Of specific concern for the commission was: 1) Whether the 
proposed tree canopy fee is fair and reasonable, and 2) Whether urban forestry costs for higher density residential 
development and Minor Land Partitions will be fair and reasonable. 
T he proposed tree canopy fee is based on tree appraisal methodology developed by the Pacific Northwest Chapter 
of the International Society o f Arboriculture. T he commission agreed it was m ore fair and reasonable to base the 
fee on tree care industry m ethodology, ra ther than crea til1g the fee without guidance from the tree care industry. 
T he commission compared the proposed fee to the existing fee in the code, as well as fees across the region. T his 
provided them further evidence that the proposed fee is fair and reasonable because it is less than the exis ting fee 
and on the lower end o f fees across the region: 
Comparison of Fee in Existing and Proposed Code 
Existing Tigard Code Proposed Tigard Code 
Mitigation Based Canopy Based 
$125/cali per inch $2.95/sq. ft. 
Fee for 12" DBH Tree = $1,500 Fee for 12" DBH Tree = $1,463 1 
1 DBH converted to canopy using the Krajicek fo rmula (see the Tree Canopy Fee memo in Volume V for more 
L __ _ _ informa_t i OI'l__()_~_th_e_ formula) 
City of Tigard Urban Forestry Code RcY isions I Volume I I 35 
35 
Regional Fee Comparison 
City Fee Fee Per Context 
Caliper Inch * 
City of Tigard $125 per caliper $125 Based on average cost to purchase, install and 
(existing) inch maintain a two-inch cali per replacement tree. 
City of Tigard $2 .95 per square $87 Based on the median wholesale cost of a three-inch 
(proposed) foot of canopy deciduous tree in the Willamette Valley ($174) . 
Beaverton $90 coniferous $45 conifer Costs are based on the purchase and planting of two-
$175 deciduous $87.50 decid. inch caliper trees to mitigate for loss of Significant 
$200 street tree $100 st. tree Trees/Groves on a 1:1 basis. 
Gresham n/a n/a No established fee in lieu program per planner on 
duty. 
Hillsboro n/a n/a No established fee in lieu program per planner on 
duty. 
Lake Oswego $328 per $164 Code strongly emphasizes protection over mitigation. 
mitigation tree 
Oregon City $290 per $145 Fee in lieu of replacement tree standards of two-inch 
mitigation tree caliper deciduous or six-foot high conifers. 
Portland $300 per caliper $300 Applies to all trees regulated under Portland code . 
inch 
Tualatin n/a n/a No established fee in lieu program per planner on 
duty. 
West Linn $175 per street $87.50 Mitigation fees not required . Applicants can pay the 
tree city $175 to install street trees, or $75 to inspect 
developer-installed trees. 
Wilsonville Market Price Market Price Applications must include the actual cost of the 
required replacement trees (generally 1:1L with 
documented bids included with application materials. 
Per planner on duty. 
Vancouver, Market Price Market Price Fee in lieu rates based on estimated market cost to 
WA purchase, install and maintain required tree units 
(based upon DBH). Applicant submits documented 
bid with application materials. 
*Fee per taliper indJ tol11m11 is an approx imate tom;ersion ~City rifTigard staff to e.rtablis/; a c:ommon unit for compartson. 
In addition to the comparison o f fees indicating the proposed fee is fair and reasonable, the peer review results 
demonstrate the proposed code has been structured so that the canopy requirements are achievable on the typical 
range o f development projects in Tigard, without requiring payment o f a fee in lieu. This is in contrast to the 
existing code where the mitigation requirements are no t achievable for many projects, particularly those with many 
large existing trees. T herefore, the commission viewed the tree canopy fee as a fa il· and reasonable option for 
choosing no t to plant or preserve trees, rather than something applicants will be required to pay for typical projects. 
36 
City o f Tigard Urban l'orcstry Code Rc,·isions I \'olumc I I y , 
The second part of the commission's cost discussion involved deciding whether the costs o f developing urban 
forestry plans for higher density residential development are excessive since the peer review results show the 
requirements can be m et through strategic planting of large stature street trees. T hey also discussed whether the 
costs for developing urban forestry plans for Minor Land Partitions are excessive since there is less pro fit associated 
with these types o f developments. 
T he commission noted that the peer review results do demonstrate that for higher density residential sites, the 
effective tree canopy requirements can be m et primarily through strategic planting of large stature street trees. 
However, they understood the incentive to maximize street tree canopy is deliberate, as street trees have particularly 
high benefit to cost ratios in urban areas. 
T he commission recognized that for street trees to achieve their potential canopy growth, adequate soil resources 
and proper planting methods are critical. The commission viewed the proposed code as placing high value on the 
role of arborists in designing and implem enting the conditions for sustainable urban tree canopy, which include 
providing adequate soil volumes. 
The commission acknowledged that requiring arborists adds cost to projects, but it is consistent with the direction 
of the Urban Forestry Code Revisions: to distribute development costs more equitably (rather than only requiring 
arborists for projects with existing trees) and to focus on es tablishing healthy future canopy (rather than only 
penalties for tree removal). T hey also recognized that the exis ting code already requires plans developed by a 
certified arborist for higher density residential projects. 
For Minor Land Partitions, again the commission noted that plans developed by a certified arborist for the 
prese1vation and planting of trees are already required by the existing code. 
Further, the commission analyzed the buildable lands inventory and found that the larges t share of buildable sites in 
Tigard is between 10,000 sq. ft. and 1 acre. Tlus m eans that Minor Land Partitions likely represent a significant 
share of future residential development in Tigard. Therefore, the comnlission decided it was important to apply the 
Urban Forestry Code Revisions to Minor Land Partitions to support Tigard's long term urban forestry goals. 
The cost es timated by staff to develop and implement an urban fores try plan for a Minor Land Partition based on 
intetv iews with local arborists is between $4,000 and $5,000 (includes inventory field work, site plan, arborist report, 
revisions based on city review and implementation inspections). However, the commission considered that this is 
sigtlificantly less than costs associated with the exis ting code for tree removal nlitiga tion which can reach $30,000 
for a Minor Land Partition (this is in addition to the cost o f developing a tree plan). 
T he comnussion did identify an opportunity for creating efficiencies when developing urban forestry plans, willie 
ensuring high quality design and implem entation. The code required a certified arborist to develop urban forestry 
plans (which involve developing a tree inventory, protection and planting plan). However, the code also required a 
landscape architect when alternative methods such as structural soils are used to m eet soil volume requirements. For 
projects that use structural soils to meet their requirements, the commission decided it would reduce costs if the 
landscape architect could also complete the urban fores try plan (without requiring a certified arborist) since 
landscape architects also have the skill set needed to inventory, protect and plan trees. 
Commission Decisions on Theme 2: T he commission decided the proposed tree canopy fee is fair and 
reasonable because it is based on tree appraisal methodology developed by the Pacific Northwest Chapter of the 
International Society of Arboriculture. In addition, they decided the proposed fee is fair and reasonable because it is 
37 
City of Tigard Urban Forestry Code RcYisiom I \'olumc I I 37 
less than the existing fee and on the lower end o f fees across the region . Finally, they decided the proposed fee is 
fa ir and reasonable because th e proposed code has been structured so that the requirements are achievable on the 
typical range of development projects in Tigard, without requiring payment o f a fee in lieu. The fee is simply an 
option for applicants that choose no t to plant or preserve trees. Therefore, the commission did not think any 
revisions to the proposed tree canopy fee were needed. 
T he commission decided that the costs for developing urban fores try plans were no t excessive for higher density 
residential development and Minor Land Partitions. T his is because the exis ting code requires arborists for these 
development typ es to create tree plans. In addition , since mitiga tion is proposed to be eliminated, costs will likely 
decrease, particularly for those projects with existing mature trees. T he commission decided it is consistent with the 
direction o f the Urban Forestry Code Revisions: to distribute development costs more equitably (rather than only 
requiring arborists for pro jects with existing trees) and to focus on es tablishing healthy future canopy (rather than 
only penalties for tree removal). Therefore, the conunission did no t think any revisions to applying the Urban 
Fores try Plan requirements to higher density residential development and Minor Land Partitions were needed. 
H owever, the commission did think that allowing landscape architects, in addition to arborists, to develop urban 
fores try plans to reduce costs by eliminating the need for hiring two urban fores try professionals was appropriate. 
Existing Conditions 
Tigard's urban forest has a rich natural and cultural history that has shaped its present conditions . 
T his section summarizes the history and existing conditions o f T igard's urban forest. 
EARLY HISTORY 
The Kalapuya (Native Americans) were the first known caretakers of Tigard's urban forest 3,500 
years before present. They used a managem.ent technique known as pyroculture which thinned 
native trees and fores ts through controlled burning to increase plant and animal food production. 
At the tin1e o f E uropean settlement in the 1850s, the canopy cover within the current city limits 
of T igard was es timated to be 52 percent. T he predominant tree species in the riparian and 
wetland areas were Oregon ash, red alder, biglea f maple, willow, black cottonwood, O regon white 
oak, wes tern red cedar, and Pacific dogwood. T he upland areas were dominated by D ouglas fir, 
biglea f maple, grand fu·, Pacific dogwood, wes tern hemlock, O regon white oak, red alder, wes tern 
red cedar, and ponderosa pine. 
Figure 4: Sketch of 
Kalapuya man drawn 
by .\! fred ,\ ga te, a 
member of the 
Wil ke~ I ~ xpedition in 
1841 
While a detailed canopy analysis for the settlement period after the 1850s has no t yet been performed, early aerial 
photography from the 1940s shows relatively large clusters o f native fores ts evenly distributed throughout Tigard. 
In between these fores t clusters was land that was cleared for agricultural and timber production . 
38 
City of Tigard Urban l'orcstry Code Rc,·isiom I \'olumc' I I .)H 
URBAN FOREST MANAGEMENT 
As an organized community, Tigard has sought to grow and manage 
its urban forest since the city's incorporation in 1961. The first 
street tree planting requirements for development were enacted in 
1967. In 1983, the city began requiring permits for the removal of 
trees on all public and undeveloped lands, and all commercial and 
industrial lands. In 1997, the city significantly revised its urban 
forestry code to require removal permits within environmentally 
sensitive lands. Also in 1997, the city began requiring tree 
protection, removal, and mitigation plans for certain types of 
development projects. The current "inch for inch" mitigation 
standard was enacted which requires, for example, cl1e replacement 
of one 12-inch diameter tree with six 2-inch diameter trees . An 
optional fee-in-lieu of replacement plantings was also allowed. 
Figure 5: 1940s aerial photo o f the city's southern 
boundary ncar Cook Park 
As fee-in-lieu deposits have accumulated, the Tree Canopy Replacement Program was developed to plant 
replacement trees within T igard's neighborhoods on public properties and along streets. Currently, $150,000 is 
budgeted annually for the Tree Canopy Replacement Program. 
Another city program, the community tree planting challenge, began in 2005 to improve the environmental quality 
of T igard's streams. The city budgets approximately $150,000 annually to meet the goal of planting 135,000 
streamside trees by 2025. 
To help coordinate, oversee, and implement Tigard's growing urban forestry program, the city hired its first urban 
forester in 1998 and appointed its fmt Tree Board in 2001. In recognition of these expanded efforts, Tigard has 
been designated as a Tree City USA by the National Arbor Day Foundation since 2001 and has received the Tree 
City USA Growth Award since 2009. 
In recent years, the Tigard community has found it increasingly important to direct efforts toward the long-term 
sustainability of the urban forest. Led by the Tree Board, in 2008 the city's first urban forest section of the 
Comprehensive Plan was adopted by council and contains broad, 20-year urban fores try goals and policies. Tlus 
important document ensures trees and forests are integrated into Tigard's long term growth and development plans. 
The Comprehensive Plan led to the more specific Urban Forestry Master Plan which was accepted by council in 
2009. The development of the Urban Forestl)' Master Plan involved extensive outreach to citizens, and local 
development and urban forestry professionals. Included in the outreach efforts was a statistically valid survey of 
Tigard residents. Among the survey results was support for development regulations (66 percent support), 
protections for trees on private property (76 percent support) and development of a hazard tree abatement program 
(60 percent support). There was also a consistent community preference for preserving significant groves of native 
trees wherever possible. 
The Urban Forestry Master Plan summarizes the input received with over 50 specific implementation items to be 
aclueved by the year 2016 when the plan will again be reviewed and updated. The majority of the implementation 
items relate to revising the urban forestry code with an eye toward increasing citywide tree canopy to 40 percent by 
the year 2047. 
39 
City of Tigard Urban Forestry Code Rc,·isions I Volume I I 39 
POLICY FRAMEWORK 
T he urban fores try code revisions exis t within the context of various federal, state, 
regional and local policies and regulations. The Urban Forestry Manual in Volume V 
includes a review of the federal, state and regional framework for the urban fores try 
code revisions in Appendix G and the local framework in Appendix H . The staff 
report in Volume II provides findings on how the urban fores try code revisions are 
consistent with and supportive o f those policies and regulations that are applicable to 
the land use elements of the urban fores try code revisions. 
URBAN FOREST CANOPY - A MEASUREMENT OF SUCCESS 
In recent years, the city has tracked changes in its urban fores t canopy using high 
resolution aerial pho tography. D espite high levels o f development activity, citywide 
tree canopy dropped only slightly from 25% in 1996 to 24% in 2007. Tigard's current 
24% citywide canopy puts it in the middle o f the range for cities in the 
metro area with neighboring places like Lake O swego towards the high 
end (47%) and I<ing City at the low end (12.5%). 
Despite Tigard's relatively stable urban forest canopy citywide, it is 
becoming increasingly fragmented with large fores t clusters being replaced 
by individual trees. In 1996, there were 63 fores t clusters over five acres in 
size and by 2007 this number had dropped to 48 fores t clusters. T his 
represents a 24% decline in an 11 -year period. 
Figure 6: Tigard 's 
C:omprchcn~ivc Plan in clud e~ a 
section dedicated to urban 
fore~ try 
T he current urban fores t canopy is not evenly distributed throughout the 
city. While residential zones have a relatively healthy 30% canopy, 
industrial, commercial, and mi"Xed used zone have much less with 16%, 
14%, and 10% canopy respectively. 
Fig ure 7: 2011 aerial photo o f the city's southern 
boundary ncar Cook Park 
Finally, the current urban fores t ca nopy is not distributed in a way to maximize environmental and econo mic 
benefits. While trees along streets and within parking lo ts are proven to provide maximum benefits, there is 
currently only 9% canopy over Tigard streets and 6% canopy over Tigard parking lo ts. 
The Urban Forestry Code Revisions are designed to address these deficiencies and support achievement of Tigard's 
long term tree canopy goals outlined in the Urban Fores try Master Plan. 
40 
City o f Tigard Urban l'orcstry CoLk Rc,·isions I \'o lumc I I 411 
City of Tigard 
COMMUNITY DEVELOPMENT DEPARTMENT 
13125 SW Hall Blvd., Tigard, OR 97223 
www. tigard-or.gov / trees I 
Volume II: Table of Contents 
Organization of the Urban Forestry Code Revisions Documents ....... .. ........................ ..... ....................... 1 
Community D evelopment Code - Planning Commission Recommendation ................................ ............ .. 3 
Ho\v to Read This Section ............................................................................. ..... ..... .... ................................ 5 
Table of Code Sections ...... ..... ............... ... ... .. ..... ......... ............ ............... ...................................................... 5 
Code Amendments 
Chapter (18.115) List ofTerms 
7 
7 
Chapter 18.120 Definitions ........................... .. .................................................................................. ........... 21 
Chapter 18.310 Summary of Land Use Permits ..................................................................... ................ 33 
Chapter 18.330 Conditional Use ..................................................................... ... ............. ... ... ............... ....... 43 
Chapter 18.350 Planned Developments ................................................................................................... 51 
Chapter 18.360 Site Development Review 57 
Chapter 18.370 Variances and Adjustments ................................... .................................... ..................... 61 
Chapter 18.390 D ecision-Making Procedures .................... ....................... .. ........................................... 65 
Chapter 18.530 Industrial Zoning ............................ ...... .................... .. ................................................ ... ... 73 
Chapter 18.610 Tigard Downtown District Development and Design Standards ...................... 7 5 
Chapter 18.620 Tigard Triangle Design Standards ................... ...... ....................................................... 81 
Chapter 18.630 Washington Square Regional Center Design Standards ....................... ................. 93 
Chapter 18.640 Durham Quarry Design Standards ................................. ........... ................... ... ............ 99 
Chapter 18.715 Density Computations ............... ............ ... ..... .... ............................................................ lOS 
Chapter 18.745 Landscaping and Screening .......................................................................................... 107 
Chapter 18.775 Sensitive Lands ................................................................................................................ 129 
Chapter 18.790 Urban Forestry Plan ................................ ................................................. .. .................... 135 
Chapter 18.798 Wireless Communication Facilities ............................................................................ 179 
Peer Review ......................................................................................... .. ... ..................................................... 185 
Tree Grove ESEE Analysis 
Section 1: Introduction and Context 
219 
225 
Section 2: Conflicting Use and Draft Limited Protection (Regulatory Incentives Program) .... ... 235 
Section 3: Tigard ESEE Analysis for STGs .... ... ..................................................................... .. ......... .. 243 
Section 4: Proposed Limited Protection ........ ...... .... ....... ....... .. ..... .............. .. .......... .. .. ... ....... ......... .. ... .. 301 
Appendix A: Tigard Tree Grove Assessment Report ............................ .. .. .. ...................... ........ .... .... . 315 
Appendix B: Impacted Taxlots and Significant Tree Grove Acreage ...... ........ .. .. ........ .. .................. 401 
Staff Report and Findings .... ....... ...... .......................................................................................... ............ ... .. 41 9 
Organization ofthe U rban Forestry Code Revisions Documents 
T he Urban Forestry Code Revisions project is presented in five volumes. Volume I provides the 
project overview and describes the process used to develop all o f the elements. Volume II is the 
land use elements o f the code, and Volume III the non land use elements. Volume IV contains the 
Urban Forestry Manual. Volume V contains technical reports and research that contributed to the 
code revisions along with details o f the public input and deliberations to date. 
Volume I I Project Overview 
Project Overview includes the following sections: 
• Project Introduction 
• Overview o f Key E lements 
• Key E lement Summaries 
o Urban Forestry Standards for D evelopment 
o Tree G rove Preserva tion Incentives 
o T ree Permit Requirements 
o Hazard Trees 
o Urban Forestry Manual 
Appendix A includes additional detail about the information used to shape the Urban 
·Forestry Code Revisions Project, and includes the following sections: 
• Process summary 
• Summary of Community Ideas and Concerns 
• Summary of Planning Commission D eliberations 
• Existing Conditions 
Volume II I Land Use Elements 
Community Development Code (Title 18) is the Planning Commission 's recommended 
draft o f the D evelopment Code. T his section includes commentary on the amendments. 
Peer Review demonstrates how the Planning Commission's recommended draft of the 
D evelopment Code and Urban Forestry Manual will work in application. 
Tree Grove ESEE Analysis is a report that addresses Statewide Planning Goal 5 -Natural 
Resources requirements for the preservation o f Significant Tree G roves. 
Staff Report and findings includes the staff recommendation for approval of the land use 
elements (Title 18 and the Comprehensive Plan Amendment) and the findings that 
demonstrate the land use elements m eet the necessary approval criteria. 
City o fTi!,>ard Urban Forestry Code Revisions I Volume II I 1 
Volume III I Non Land Use Elements 
Tigard Municipal Code is the staff proposed draft of the Municipal Code (Title 8 and 
other Municipal Code titles). This section includes commentary on the amendments. 
Volume IV I Urban Forestry Manual (Administrative Rules) 
Urban Forestry M anual consists o f administrative rules that implement the technical 
details of the urban forestry related code provisions in Title 8, Title 18 and o ther applicable 
titles in the Tigard Municipal Code. 
Volume V I Additional Background Materials 
Planning Commission Deliberations details Planning Commission discussion and 
decisions during the public hearing process. 
Amendment Requests Document for the Planning Commission lists code amendment 
requests received in response to the first Planning Commission public hearing and staff 
responses. 
Outstanding Issues for the Urban Forestry Code Revisions includes additional 
information on the outstanding issues that were further deliberated by the Planning 
Commission before making their flnal recommendation to City Council on May 7, 2012. 
Log of Input lists the input received and any code changes from the last meeting of the 
CAC to the staff proposed draft of the Urban Forestry Code Revisions to Planning 
Commission. 
CAC Guiding Principles includes the consensus view of the Citizens Advisory Committee 
(CAC) developed to help guide the legislative adoption process. 
Tree Values includes information and current research on the environmental, economic, 
social and aes thetic benefits of trees. 
Canopy Standards explains the reasons for adopting tree canopy cover requirements as 
well as the methods used to arrive at the requirements. 
Soil volume details research about the soil volume required to support a mature tree 
canopy. 
Tree Canopy Fee discusses research used to develop a square foot value for tree canopy. 
Regulatory Comparison is an excerpted report prepared by Metro and the Audubon 
Society that summarizes and con>pares regional urban foreS li) ' programs and regulations. 
Urban Forestry Master Plan is the City of Tigard 's recommended plan for achieving the 
urban fores t1-y goals in the Comprehensive Plan. 
Ci t} of Tigard Urban Fores try Code RcYisions I \'olumc II I 2 
Urban Forestry Code Revisions 
Community Development Code -
Planning Commission 
Recommendation 
City of Tigard Urban Forestry Code Revisions I Volume 11 I 3 
'
-c 
Community Development Code -Planning Commission Recommendation 
H ow to Read This Section 
This section is organized by Community Development Code chapter number. Odd-numbered 
pages show the existing language with (proposed/ recommended/ adopted) amendments. Text that 
is (proposed/recommended) to be added to the code is shown with double underlines. Text that is 
(proposed/ recommended) to be deleted is shown with strikethrough. 
Even-numbered pages contain commentary on the amendments, which establish, in part, the 
legislative intent in adopting these amendments. Staff recommends focusing on the commentary to 
gain a better understanding of the purpose of the code amendments. 
The Urban Forestry Manual consists of administrative rules that implement the details of the urban 
forestry related code provisions in Title 8, Title 18 and other applicable titles in the Tigard Municipal 
Code. Section 8.02.040 of the Tigard Municipal Code enables administrative rulemaking for the 
Urban Forestry Manual. The city manager is authorized to adopt and amend the Urban Forestry 
Manual according to the procedures in Chapter 2.04 after council adoption of Section 8.02.040. The 
Urban Forestry Manual is referenced as if it has already been adopted in order to demonstrate how it 
relates to the code. 
Table of Code Sections 
Chapter (18.115) List ofTerms ...... .. ...... ... ... .. .. ..... .. ..... ...................................................................... 3 
Chapter 18.120 Definitions .................. ............................................................................................ 17 
Chapter 18.310 Summary of Land Use Pemuts ....................... .... ............................................. 29 
Chapter 18.330 Conditional Use .. ... .... .. ..... ... .................................................................... .. ........... 39 
Chapter 18.350 Planned D evelopments ............................................. .. ...... .. ..................... .. .. ....... 47 
Chapter 18.360 Site Development Review .................................................................................. 53 
Chapter 18.370 Variances and Adjustments ................................................................ .. ... ... ..... .. 57 
Chapter 18.390 Decision-Making Procedures ............................................................................ 61 
Chapter 18.530 Industrial Zoning ............................................................................. ......... ... ......... 69 
Chapter 18.610 Tigard Downtown District Development and Design Standards .. .. ... .. 71 
Chapter 18.620 Tigard Triangle Design Standards ...................................................... .... ... .. .. .. 77 
Chapter 18.630 Washington Square Regional Center Design Standards ... ..... .. ................. 89 
Chapter 18.640 Durham Quarry Design Standards ...................... ..... ...... ................................ 95 
Chapter 18.715 Density Computations .. .................................................................................... 101 
Chapter 18.745 Landscaping and Screening ............................................................................. 103 
Chapter 18.77 5 Sensitive Lands ............... ................................. .... ..... .................... .. .... .... .. ..... ...... 125 
Chapter 18.790 Urban Forestry Plan ............ .... .. ... ........ ... ... ..... .......................... .. ................... ... 131 
Chapter 18.798 Wireless Commmucation Facilities ............................................................... 175 
City of Tigard Urban Forestry Code Re,·isions I Volume II I 5 
Commentary 
18.115 List o f Terms 
Chapter 18.115 (List o f Terms) is a newly codified chapter of the Tigard D evelopment Code (fD C) 
that is provided for easy reference of defined terms in Chapter 18.120 (Definitions). N ew, revised 
and consolidated tree / urban fores try related definitions in Chapter 18.120 are listed in Chapter 
18.115. 
2 
City of Tigard Urban I 'ore, try Code Rc,-i,iom I \' olumc II I (, 
Chapter (18.115) 
List of Terms 
Code Amendments 
The following terms are defined in Chapter 18.120, Definitions, unless indicated otherwise. 
Abandoned Sign See Chapter 
18.780, Signs 
Abut 
Abutting Lots 
Accept 
Access 
Accessory Building 
Accessory Dwelling Unit See 
Du;e/ling-Re/ated Dpnitions 
Accessory Structure 
Acre 
Active Use Facilities See 
Open Space Facility-Related 
Dpnitions 
Addition 
Adjacent Lots See Abutting 
Lots 
Adjoining Lots See Abutting 
Lots 
Administrative Action 
Adult Bookstore See Adult 
Entertainment-Related 
Dpnitions 
Adult E ntertainment-
Related Definitions 
• Adult Bookstore 
• Adult Motion Picture 
Theater 
• Specified Anatomical 
Areas 
• Specified Sexual Activities 
Adult Motion Picture 
Theater See Adult 
Entertainment-Related 
Dpnitions 
'A'-Ftame Sign See Chapter 
18.780, Signs 
Aisle 
Alley 
Alteration, Structural 
Alternative Access 
Amendment 
Amenity 
Americans with Disabilities 
Act 
Annexation 
Antenna See also C!Japter 
18.798, Wirelm 
Communication Facilities 
Apartment See Du,elling-
Related Dpnitions 
Appeal 
Applicant 
Application 
Approval Authority 
Approved Plan 
Arcade See Design-Related 
Dpnitions 
Archaeological Site 
Area See C!Japter 18.780, 
Signs 
Argument See Section 
18.3 90.080, General 
Provisions 
Assessed Valuation 
Attached Dwelling See 
Dwelling-Related Dpnitions 
Awning See Design-Related 
Dpnitions 
A wrung Sign See Chapter 
18.780, Signs 
Balloon See Chapter 18.780, 
Signs 
Band See Design-Related 
Dpnitions 
Banner See Chapter 18.780, 
Signs 
Base Flood See Flood-Related 
Dpnitions 
Basement 
City o f Tigard Urban Forestry Code ReY isions I Volume II I 7 
Bay See Design-Related 
D pnitions 
Belt Course See Design-
Related Dpnitions 
Bench Sign See Chapter 
18.780, Signs 
Berm 
Bike Lane 
Bikeway 
Billboard See Chapter 18.7 80, 
Signs 
Buildable Area 
Building 
Building Envelope 
Building, Primary 
Building Height 
Building Official; See also 
C!Japter 18.780, Signs 
Building Permit 
Business See Chapter 18.7 80, 
Signs 
Caliper See Tree Related 
Dqfinition r 
Canopy See Design-Related 
Dpnitions 
Certified Arborist See Tree 
Related Dqfinition r 
Certified Tree Risk Assessor 
See Tree Related Definitionr 
Canopy Cover See Chapter 
18.790, Tree Rffl:tJ~ttl 
Chamfer See Design-Related 
Dpnitions 
Change of Use 
City 
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City E ngineer 
City of Tigard 
City Recorder 
Collocation See Chapter 
18.798, Wireless 
Communication Facilities 
Column See Design-Related 
Definitions 
Commercial Forestry See 
Chapter 18.790, Tree 
Re-:nf}tJtt/ 
Commission 
Common Wall 
Complete and E ntire 
Complex 
Comprehensive See 
Comprehensive Plan-Related 
Definitiom 
Comprehensive Plan-
Related Definitions 
• Comprehensive 
• Generalized 
• Land 
• Plan Coordination 
Conditional Use 
Construct See Chapter 
18.780, Signs 
Contiguous 
Contiguous Lots See 
Abutting Lots 
Corner Lot See Lot-Related 
Definitions 
Corner Side See Yard-Related 
Definitions 
Cornice See Design-Related 
Definitions 
Council 
Covered Soil Volume See 
Tree Related D~finition r Area-
See LcmdS£aj:Jing Related 
Dtjit.:itif}ns 
Cul-de-sac 
Cultural Institution 
Auxiliary Sign See Chapter 
18.780, Signs 
Cutout See Chapter 18.780, 
Signs 
Dedication 
Dedication, Fee In Lieu Of 
Deed 
Demolish 
Density 
Density Bonus 
Density Transfer 
Design-Related Definitions 
• Arcade 
• Awning 
• Band 
• Bay 
• Belt Course 
• Canopy 
• Chamfer 
• Column 
• Cornice 
• Eaves 
• E ntry 
• Frieze 
• Marguee 
• Medallion 
• Parapet 
• Pilaster 
• String Course 
• Transom 
• Turret 
• Visible Transmittance 
Detached Dwelling See 
Du;el/ing-Related Definitions 
D evelopment 
Development Adjustment 
SeeSection 18.370.020, 
Ar!Justments 
City of Tigard Urban Forestry Code ReYisions I Volume II I 9 
Code Amendments 
Development Impact Area 
Development Review See 
Chapter 18.780, Signs 
Development Site 
Diameter at Breast Height 
(PBH) See Tree Related 
Dtfinition.r 
Directional Sign See Chapter 
18.780, Signs 
Director 
Display Surface See Chapter 
18.780, Signs 
Drainage Way 
Dripline See Tree Related 
DeJinition.r 
Drive-Through Facility 
Driveway 
Duplex See Dwelling-Related 
Definitions 
Dwelling See D1velling-Related 
Definitions 
Dwelling-Related 
Definitions 
• Accessory Dwelling Unit 
• Apartment 
• Attached Dwelling 
• D etached Dwelling 
• Duplex 
• Dwelling 
• Manufactured Home 
• Multiple-Family Dwelling 
• Single-Family Dwelling 
Easement 
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Eaves See Design-Related 
Df!ftnitions 
Effective Date See Sedion 
18.3 90.080, General 
Provisions 
Egress 
E lectrical Sign See Chapter 
18.780, Signs 
E lectronic Information Sign 
See Chapter 18.780, Signs 
E nlargement 
E ntry See Design-Related 
Df!ftnitions 
E ntryway Sign See Chapter 
18.780, Signs 
Evidence See Section 
18.3 90.080, General 
Provisions 
Exception 
FAA See Chapter 18.798, 
Wireless Communication 
Facilities 
Face 
Face of a Building See 
Chapter 18.780, Signs 
FCC See Chapter 18.798, 
IPireless Communication 
1-'acilities 
Fence, Sight-Obscuring 
Final Action 
Final Decision See Final 
Action 
Final For Purposes Of 
Appeal See Sedion 
18.3 90.080, General 
Provisions 
Final Order See Final Action 
Findings 
Flag Lot See Lot-Related 
Df!ftnitions 
Flashing Sign See Chapter 
18.780, Signs 
Floodplain See Flood-Related 
Df!ftnitions 
Flood-Related Definitions 
• Base Flood 
• Floodplain 
• Floodway 
• Floodway Fringe 
Floodway See Flood-Related 
Df!ftnitions 
Floodway Fringe See Flood-
Related Df!ftnitions 
Floor Area 
Floor Area Ratio 
Flush Pitched Roof Sign See 
Chapter 18.780, Signs 
Freestanding Sign See 
Chapter 18.780, Signs 
Freeway Interchange See 
Chapter 18.780, Signs 
Freeway-Oriented Sign See 
Chapter 18.780, Signs 
Frieze See Design-Related 
Df!ftnitions 
Front See Yard-Related 
Df!ftnitions 
Frontage See also Chapter 
18.7 80, Signs 
Front Lot Line See Lot-
Related Df!ftnitions 
Garage 
Generalized See 
Comprehensive P !an-Related 
Df!ftnitions 
Glare 
Guyed Tower See Chapter 
18.798, Wireless 
Communication F milities 
City of Tigard Urban Forestry Code Re,·isions I Volume II I 11 
Code Amendments 
Habitable Floor Area 
Hazard Tree See Tree Related 
DeJinitions 
Hazard Tree Abatement See 
Tree Related D~finition.r 
Hazard Tree Owner or 
Responsible Party See Tree 
Related Definition.r 
Heritage Tree See Tree 
Related D~finition r 
Hazardous Tree See ChtijJ!er 
18.790, Tree RemoYfl! 
Home Occupation 
Homeowners Association 
Household 
Housing Complex See 
Chapter 18.780, Signs 
Immediate or Serious 
Danger See Chapter 18.780, 
Signs 
Impact Analysis 
Impervious Surface 
Implementing Ordinance 
Improved Lot See Lot-
Related Df!ftnitions 
Improvement 
Industrial Park See Chapter 
18.780, Signs 
Ingress 
Interior Lot See Lot-Related 
Df!ftnitions 
Land See ComprehensitJe Plan-
Related Df!ftnitions 
Land Form Alteration 
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Landscape Architect 
Landscaping 
Landseapllig Related 
Definitions 
• Covered Soil Area 
• Open Soil 
• Root Paths 
• ~nil Volnmc rll knl>ttiA f'l ~ 
Lattice Tower See Chapter 
18.798, Wireless 
Communication rcmlities 
Lawn Sign See Chapter 
18.7 80, Signs 
Legal E ntity See Chapter 
18.7 80, Signs, "Business" 
Legislative 
Lighting Methods See 
Chapter 18.780, Signs 
Loading Area See Loading 
Space 
Loading Space 
Lot See Lot-Related Difinitions 
Lot Area See Lot-Related 
Difinitions 
Lot Averaging See Lot-
Related Difinitions 
Lot Coverage See Lot-Related 
Difinitions 
Lot D epth See Lot-Related 
Difinitions 
Lot Line See Lot-Related 
Difinitions 
Lot Line Adjustment See 
Lot-Related Difinitions 
Lot of Record See Lot-
Related Difinitions 
Lot-Related D efinitions 
• Corner Lot 
• Flag Lot 
• Front Lot Line 
• Improved Lot 
• Interior Lot 
• Lot 
• Lot Area 
• Lot Averaging 
• Lot Coverage 
• Lot D epth 
• Lot Line 
• Lot Line Adjustment 
• Lot of Record 
• Lot Width 
• Rear Lot Line 
• Side Lot Line 
• Substandard Lot 
• Tax Lot 
• Through Lot 
• Zero Lot Line 
Lot Width See Lot-Related 
Difinitions 
Maintenance See Chapter 
18.780, Signs 
Manufactured Home See 
Du;elling-Related Difinitions 
Marquee See Design-Related 
Difinitions 
Medallion See Design-Related 
Difinitions 
Median Tree See Tree Related 
D&finition r 
Minimal Use Facilities See 
Open Space Faciliry-Related 
Difinitions 
Mitigation 
Mixed Solid Waste See 
Chapter 18. 7 55, Mixed Solid 
IF aste And Reryclable Storage 
Mixed-Use D evelopment 
Ci ty of Tigard Urban Forestry Code Revisions I Volume II I 13 
Code Amendments 
Mobile Home 
Mobile Home Park 
Mobile Home Subdivision 
Monopole See Chapter 
18.798, Wireless 
Communication Facilitie.r 
Moving Sign See Chapter 
18.780, Sign.r 
Multiple-Family Dwelling 
See Du;elling-Related 
Difinition.r 
Multi-Unit Residential 
Building See Chapter 
18.755, Mixed Solid Waste 
And Reryclable Storage 
Neighborhood Activity 
Center 
Noise 
Nonconforming Sign See 
Chapter 18.780, Signs 
Nonconforming Situation 
Non-Residential Building 
See Chapter 18.755, Mixed 
Solid Wa.rte And Reryclable 
Storage 
Non-Structural Trim See 
Chapter 18.7 80, Signs 
N uisance T ree See Tree 
Related D£finitionJ 
O ccupancy Permit 
O ff-Site Impact 
Off-Site Improvement 
Open Grown Tree See Tree 
Related D£finition.r 
Open Soil Volume See Tree 
Related D£finition r See 
LandJcaping-Related 
DifinitionJ 
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Open Space Facility-Related 
Definitions 
• Active Use Facilities 
• Minimal Use Facilities 
• Passive Use Facilities 
Oregon Administrative 
Rules 
Oregon Revised Statutes 
Outdoor Storage 
Owner 
Painted Wall Decorations 
See Chapter 18.7 80, S igm 
Painted Wall Highlights See 
Chapter 18.780, Signs 
Painted Wall Sign See 
Chapter 18.780, Signs 
Parapet See Design-Related 
Definitiom 
Park 
Parking Lot Tree See Tree 
Related Definition r 
Parking Space 
Partition 
Party 
Passive Use Facilities See 
Open Space Faciliry-Related 
Definitions 
Perimeter 
Permitted Use 
Person See also Chapter 
18.780, Signs 
Pilaster See Design-Related 
Definitions 
Plan Coordination See 
Comprehensive Plan-Related 
Definitions 
Plat 
Premises See Chapter 18.780, 
Signs 
Projecting Sign See Chapter 
18.780, Signs 
Projection See also Chapter 
18.780, Signs 
Provider See Chapter 18.798, 
Wireless Communication 
Facilities 
Pmniftg See ChdjJter 18.790, 
Tt'f!e Re?mYal 
Public Business Day 
Public Support Facilities 
Quasi-] udicial 
Reader-Board Sign See 
Chapter 18.780, Signs 
Rear See Yard-Related 
Definitions 
Rear Lot Line See Lot-Related 
Definitiom 
Receipt 
Recreational Vehicles 
Remodel 
Removal See ChdjJter 18.790, 
Tree RmtflYal 
Reserve Strip 
Residence 
Residential Trailer 
Responsible Party, See 
Section 18.230.030, Penalry 
Revolving Sign See Chapter 
18.780, Signs 
Right-of-Way 
Road 
Roof 
Roof Line See Chapter 
18.780, Signs 
Roof Sign See Chapter 
18.780, Signs 
Root Paths See Landst:aping 
Relt~ted DdfflititJtts 
Rotating Sign See Chapter 
18.780, Signs 
SCftsitive Laftds See ChdjJtn· 
18.790, Tree RmlfJYal 
Setback 
City o f 'figard Urban Fore~ try Code ReYisions I Volume II I 15 
Code Amendments 
Shopping Center See Chapter 
18.780, Signs 
Shopping Plaza See Chapter 
18.780, Signs 
Side See Yard-Related 
Definitiom 
Side Lot Line See Lot-Related 
Definitions 
Sign See Chapter 18.7 80, Signs 
Sign Structure See Chapter 
18.7 80, Signs 
Significant Tree Grove See 
Tree Related Definition r 
Single-Family Dwelling See 
D1velling-Related Definitions 
Site 
Slope 
Soil Vohune Calet1lations 
See LandscdjJing Relt~ted 
Dtfinitirms 
Source-Separated 
Recyclable See C!Japter 
18. 7 55, Mixed Solid IP aste 
And Rerydable Storage 
Special Adjustments, See 
Section 18.370.020, 
Aqjustments 
Specified Anatomical Areas 
See Adult Entertainment-
Related Definitions 
Specified Sexual Activities 
See Adult Entertainment-
Related Definitions 
11 
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Stand (Of Trees) Jee Tree 
Related Dgfinition.r 
Stand Grown Tree Jee Tree 
Related Dr;finition r 
Storage Area See Chapter 
18. 7 55, Mixed Solid Wa.rte 
And Reryc/ab/e S forage 
Story 
Story, First 
Story, Half 
Street 
Street, Private 
Street, Public 
Street Tree Jee Tree Related 
Dyfinition r 
String Course See De.rign-
Related Difinitiom 
Structural Alteration See 
Chapter 18.780, Sign.r 
Structure 
Subdivision 
Substandard Lot See Lot-
Related Difinition.r 
Substantial Improvement 
Surface Street See Chapter 
18.780, Sign.r 
Tax Lot See Lot-Related 
Difinitiom 
Temporary Sign See Chapter 
18.780, Sigm 
Temporary Use 
Tenant Sign See Chapter 
18.780, Sign.r 
Through Lot See Lot-Related 
D ifi ni tio 11.f 
Tigard-Based Nonprofit 
Organization 
Traffic Flow Plan 
Transom See De.rign-Related 
Difinitiom 
Tree Jee Tree Related 
Definition r See Clba Chr:fflter 
18.79(), Tree Mliat'Cit 
Tree Canopy Jee Tree Related 
Definition.r 
Tree Canopy Cover 
Effective Jee Tree Related 
Definition r 
Tree Care Industry 
Standards Jee Tree Related 
Definition r 
Tree Related Definitions 
• Caliper 
• Certified Arborist 
• Certified Tree Risk 
Assessor 
• Covered Soil Volume 
• Diameter at Breast Height 
(DB H) 
• Dripline 
• Hazard Tree 
• Hazard Tree Abatement 
• Hazard Tree Owner or 
Responsible Party 
• Heritage Tree 
• Median Tree 
• Nuisance Tree 
• Open Grown Tree 
• Open Soil Volume 
• Parking Lot Tree 
• Significant Tree Grove 
• Stand (Of Trees) 
• Stand Grown Tree 
• Street Tree 
• I.t:e.e_ 
• Tree Canopy 
• Tree Canopy Cover 
Effective 
• Tree Care Industrv 
Standards 
• Tree Removal 
City of Tigard Urban Forestry Code ReYisions I Volume I I I 17 
Code Amendments 
• Understory Tree 
Tree Removal Jee Tree 
Related Definition r 
Turret Jee Derign-Related 
Definitions 
Understorv Tree Jee Tree 
Related Definitions 
Uniform Building Code See 
Chapter 18.7 80, S igm 
Use 
Vehicle Parking Space 
Visible Transmittance See 
De.rign-Related Difinition.r 
Vision Clearance Area 
Visual Obstruction 
Wall Sign See Chapter 18.780, 
Sigm 
Wetlands 
Will 
Window 
Wireless Communication 
Facility See Chapter 18.798, 
Wirele.f.f Communication 
Facilities 
Wireless Communication 
Facility, Attached See 
Chapter 18.798, Wirelm 
Communication f'acilities 
Wireless Communication 
Transmissions Towers See 
Chapter 18. 798, Wirele.r.r 
Communication Fadlitie.r 
Yard See Yard-Related 
Difinitiom 
• 
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Yard-Related Definitions 
• Corner Side 
• Front 
• Rear 
• Side 
• Yard 
Zero Lot Line See Lot-Related Difznitions 
Zoning District 
15 
City of Tigard Urban Forestry Code ReYisions I Volume II I 19 
Commentary 
18.120.030 Meaning of Specific Words and Terms 
The def~utions that were previously included in Chapter 18.790 and Title 9 have been moved 
into Chapter 18.120 in o rder to consolidate all urban fores try relevant defitutions into one 
chapter in the Tigard D evelopment Code. Existing tree related defirutions that have been 
substantially modified have been struck and replaced with new defuutions. D efulitions in 
Chapter 18.790 have been copied to Title 8, Urban Fores try, to ensure consistency o f terms 
between Title 8 and Title 18. Bo th Title 8 and Title 18 specify that the title defulitions apply to 
adnUllistrative rules (in tills case the Urban Forestry Manual) . 
In Title 18, existing and proposed tree related defulitions have been further consolidated under a 
"tree related defuutions sec tion" so that a developer or arborist/ landscape arclutect seeking to 
apply the defuutions can find all o f the tree related defmitions in one place. 
T he term "development impact area" is a new term that was crea ted for Chapter 18.790 (Urban 
Forestry Plan) as a catchall term for any type o f ground disturbance on a site. Trees can be 
severely impacted by any ground disturbance on a site, and Section 10 o f the Urban Forestry 
Manual requires that a complete tree preserva tion and removal site plan display the development 
impact area . Since the concept of the development impact area may be useful for future code 
amendments besides trees, it is no t included as one o f the tree related defuutions. 
I(, 
Cit:r of T igard Urban l;oreW')" Code Rc'\'isions I \'olumc II I 20 
Chapter 18.120 
Sections: 
18.120.010 
18.120.020 
18.120.030 
18.120.010 
[No change.] 
18.120.020 
[No change.] 
18.120.030 
DEFINITIONS 
Meaning of Words Generally 
Meaning of Common Words 
Meaning of Specific Words and Terms 
Meaning of Words Generally 
Meaning of Common Words 
Meaning of Specific Words and T erms 
Code Amendments 
A. For additional words and terms, also see Use Categories (Chapter 18.130); Mixed Solid 
Waste and Recyclable Storage (Chapter 18.755); Sensitive Lands (Chapter 18.775); Signs 
(Chapter 18.780); Tfee Removal (Chaptn 18.790); and Wireless Communication Facilities 
(Chapter 18. 798). As used in this title and corresponding administrative mles, the following 
words and phrases mean: 
1. through 41. 
[No change] 
4 2. "Caliper" The cliametef of a tree trunlr measmed at a preseribed height. 
Renumber definitions 43-59 
60. "Covered soil afea" An afea of soil that is undef pavement and specially designed 
accon'l:n'lodate tree root gw wth. 
Renumber definitions 61-70 
71. "Development Impact Area" - The area on a site or right of way associated with a site 
affected b , b . . } any and 11 . mldmgs structu a stte or right of . 
graY I d res walls · l>'ll¥ llDjltQ <-<- . at<as utiliti . parking and load· .Y<:m<nta indudiu Iandscapmg. Ib . es lttlgatiQn e . mg an:as street . g but UQI limitl:d 
demo!itiQn tr o tmpa<t an:a alsQ q':"mcnt storago llDjltDYoments payod ~ 
exca ' . « t<lllilYal - . te ers to a OQUStru<bQU . an 
unon orsoil d . ttoru:bmg b . teas of grad· . parkmg a d !Sturbanoc mmg and mg filling . . n - •llJ' Qtber acti . . stQokpiling vtties that . reqmre 
17 
City of Tigard Urban Forestry Code Revisions I Volume 11 I 21 
Commentary 
18.120.030 Meaning o f Specific Words and Terms 
The term "landscape architect" is also a new term that specifies their registration requirements 
with the State o f Oregon. Chapter 18.790 allows landscape architects, in addition to arborists, to 
create urban forestry plans. 
The following new or substantially modified definitions have been included in Chapter 18.120: 
Caliper: The term caliper is referenced throughout the code and Urban Forestry Manual when 
specifying minimum size o f nursery trees. T he term caliper follows tree care industry standards. 
Certified arborist: T his term clarifies that certified arborists are certified by the International 
Society of Arboriculture. 
Certified tree risk assessor: This term clarifies that certified tree risk assessors are certified by the 
International Society of Arboriculture. 
18 
City of Tigard Urban Forestry Code Rc,·isions I \'olumc II I 22 
Code Amendments 
Renumber definitions 71-103 
104. "Landscape Architect" - An individual regis tered with the Oregon State Landscape 
Architect Board as a registered landscape architect. 
Renumber definitions 103-120 
121. " Open soil" An unpaved area of soil sunoundi:ng a tree, which contains existing, new 
or sn1:ended soil. 
Renumber definitions 122-150 
1 c:.1 ''D ,..... ........ .... _ ....... 1 .... .... '' r,..... _ .... ......... " ... ..... ...-l _ ....... t .. ..... .... t .......... .... ........... ..... ..... .... ..... .....;; ........ ....... ,..... ... ....1 ........ ~ ..... ..... - ..... ..... ..... ~- .... ... ........ ......... ~~ --- ..... ... ............... ... ..... .... 
I .. ri; -- IcvvL pau~~m~ pllLII0 LII«L uJc acxauv:ri vx uxania5c JLIIPJ LV f:)IVC IVVGJ a 
way to grow out of the tree space and under pavement in order to access better planting 
soils. Root paths can connect tree spaces and adjacen t green spaces. 
Renumber definitions 152-154 
155. "Soil wlume calculations" Stun total of soil voltunes from each design method used 
for a tree. A soil depth of three feet is sssumed. Soil volume (cubic feet) - open soil 
area Qength x width x depth) (feet) + covered soil area Qength x w'idth .< depth) (feet) + 
root path length (feet) x 0.25 + green space area Qength x v.'idth x depth) (feet). 
*Include only applicable soil areas and design methods for each tree. 
Renumber definitions 156-169 
170. ~Tree-related definitions::.?. -
!!: "Ca4per" T h . e tree care . d ln ustry stand d £ aror m . easunng the t . runk dtameter of 
nursery stock. Caliper is the avera e dia . 
m easured six (6) inches above the gro!nd fo~nete\ of the trunk of a nursery tree 
of four (4) mches in diameter (when measure~r~; s le~s than or equal to an average 
the trunk of a nursery tr . (6) mches above ground) Wh 
ee ts grea ter than an avera f £ . . en (when measured six (6) inch b ge oour (4) mches in diameter 
· es a ove ground) cali · 1 . 
mches above ground (see figure 18.1 20:3). per ts ue average dtameter at 12 
h,_ "Certified Arborist" - An individual certified by the International Society of 
Arboriculture as a certified arborist. 
k "Certified Tree Risk Assessor" - An individual certified bv the International Socien' 
of Arboriculnue to conduct tree risk assessments. 
19 
City of Tigard Urban Forestry Code Revisions I Volume II I 23 
Commentary 
18.120.030 Meaning of Specific Words and T erms 
Covered soil volume: This definition is for Sections 12 and 13 o f the Urban Forestry Manual 
which allows soil volume requirements for street trees and parking lo t trees to be met 
underneath pavement when certain design criteria are met. 
Diameter at breast height (DBH): T he term DBH is referenced throughout the code and Urban 
Forestry Manual when specifying the size of trees that are subj ect to various regulations. The 
term DBH follows tree care industry standards. 
Drip line: This definition is primarily for Section 10 o f the Urban Forestry Manual to clarify what 
portion o f a tree is eligible for the effective canopy requirement. 
Hazard tree: The term hazard tree has been made more specific to the International Society o f 
Arboriculture Standards so that a more objective evaluation can be made as to what constitutes a 
hazard tree. A tiered system of rating hazards ensures the risks associated with small diameter 
tree parts are no t understated while the risks associated with large diameter tree parts are no t 
overstated. 
H azard tree abatement: T he term hazard tree abatement clarifies that abatement is reducing risk 
below the established threshold. T his can be accomplished through pruning or o ther means, not 
solely through tree removal. 
H azard tree owner or responsible party: H azard tree issues are often highly contentious, so the 
hazard tree owner or responsible party definition is veq specific in assigning ownership and / or 
responsibility for the tree in question . 
20 
City of Tigard Urban Fore> try Code Rc,·isiom I Volume II I 24 
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Commentary 
18.120.030 Meaning of Specific Words and Terms 
H eritage t:l"ee: T lus term. has been revised slightly from the existing defitlition to remove 
reference to Chapter 9.08 since heritage trees will be administered through Chapter 8.16. 
Median t:l"ee: T ills term was created to distinguish between median t:l"ees (which are between 
verucle t:l"affic) and street t:l"ees, since median t:l"ees are the responsibility of the city. 
N uisance t:l"ee: A nuisa nce tree list has been added to the Urban Forestry Manual to specify the 
types of t:l"ees that are prorubited from planting or receiving credit towards the effective canopy 
requirement. A nuisance t:l"ee is defined as any t:l"ee on the nuisance list. 
Open grown tree: Open grown trees are distinguished from stand grown trees in Section 10 of 
the Urban Forestry Manual so that arborists / landscape architects do not have to inventory every 
tree in a stand as currently required. Arborists/ landscape arcrutects will only have to inventory 
open grown or isolated trees, and stands of t:l"ees can be delineated at their edges. T lus will cut 
down on unnecessary inventory work. A defmition of the two types o f t:l"ees is required to 
distinguish the two. 
Open soil volume: As with covered soil volume, tlus definition is for Section 12 and 13 of the 
Urban Fores try Manual to clarify how to calculate soil volumes for trees. 
Parking lot t:l"ee: Parking lo t t:l"ees are explicitly defined since they are required by Chapter 18.745 
to provide canopy over parking areas and referenced extensively in Section 13 of the Urban 
Forestry Manual. 
Sigtlificant t:l"ee grove: A defmition for sigruficant t:l"ee groves is needed since flexible standards 
and preserva tion incentives that are specific to sigtlificant tree groves have been added to 
Chapter 18.790. A sigtlificant tree grove is a native "s tand o f trees" (ah·eady defmed) that has 
been identified as sigruficant through the Statewide Land Use Planrung Goal 5 process. A 
sigruficant tree grove map is available through a publicly accessible mapping program. 
Stand (o f t:l"ees): Section 10 of the Urban Fores try Manual allows groups of stand grown trees 
(s tands) to be delinea ted at their edges. A defuution of stand (of trees) is provided for additional 
guidance as to what is considered a stand. 
Stand grown tree: A defuution of stand grown tree is required to distinguish it from open grown 
tree so that arborists / landscape arcrutects do not have to inventory every tree in a stand as 
currently required. Section 10 of the Urban Forestry Manual allows stands of trees to be 
delineated at their edges. 
Street tree: T lus term clarifies the size and location thresholds that defme a street t:l"ee. The 
defmition also distinguishes street trees from median trees . 
22 
Citr o f Tigard Urban l'orcs try Code Rc,·isions I \ "o lumc II I 26 
Code Amendments 
k "H .· T " .entageree - Any tree or stand of trees of landmark importance due to age 
size species horticultural quality h · . . h . · or tstonc tmport h h 
aentage tree by Tigard City Council.ance t atas been approved as 
k_ "Median Tree" - Any tree within the public right of way under City of Tigard 
jurisdiction between opposing lanes of vehicular traffic. Trees in the centers of cui-
de-sacs and roundabouts within the public right of way under City of Tigard 
jurisdiction shall also be considered median trees. 
~ "Nuisance Tree" - Anv tree included on the Nuisance Tree List in the Urban 
Forestrv Manual. 
llh "Ogen Grown Tree" A · h h - ny tree t atas grown and established in an isolated 
manner without significant compeuuon for light space and nutrients from other 
trees. Open grown trees generally retain more foliage develop greater tmnk tapers 
have more extensive root svstems and are more resistant to windthrow than stand 
grown trees. 
n._ "Open Soil Volume" - An unpaved volume of soil which contains existing new or 
amended soil with the physical chemical and biol . . . 
support the growth of a tree. oglCal properties necessary to 
_ny tree used to meet the requirements in Section Q_,_ "Parking Lot Tree" A · 
18.745.050(E). 
p,. "Significant Tree Grove" - A stand of trees that has been identified as significant 
through the Statewide Land Use Planning Goal 5 process. A Significant Tree 
Grove Map is maintained by the Director. 
· · f d · trees often predorninantlx "Stand (Of Trees)" A dtstl11ct area o stan gro~vn: . ~ 
9= native and with contiguous canopies which form a vtsual and / or bwlogtcal umt. 
J;. "Stand Grown Tree" - Any tree that has grown and established in close association 
with other trees and as a result has experienced significant competition for light 
space and nutrients from other trees. Stand grown trees generally retain less 
foliage develop less trunk taper have less extensive root systems and are less 
resistant to windthrow than open grown trees. 
§: "Street Tree" - Any tree equal to or greater than 1 1/2 inch caliper or DBH within a 
public right f und . : o way under Ci . er C
1
ty f T. . ty of Ttgard · · d . . Ji -- - ~rd 1 -· ,r · - - nmuono oa_pot or DllH " . uuuotJon m an . _nor tastmtnt fo. . 
the . outstde of a p bli . y nee equal to . t QnbW: aoom 
oty oan demo _u __c nght of w 
0
' gttatot than 1 1 
reqnittmtnts fu nsttate was planted m ay m easemtnt for publi - U mob 
sttt<t t _ ! a cuy pennit _ . Pt<St!Ytd " a o aooess that =~:!=!-.!.tt:.eee_ss_._. or proJect. M d. street tree to e_tan trees sh ll meet the _a_ not be . constdered 
23 
City of Tigard Urban Forestry Code Rc1·isions I Volume II I 27 
Commentary 
18.120.030 Meaning o f Specific Words and Terms 
Tree: T he definition o f tree is revised using the standard definition of tree by the International 
Society of Arboriculture. 
T ree canopy: Tree canopy is a central theme of the revised code and forms the basis for many o f 
the code revisions and corresponding administrative procedures . T he term tree canopy is closely 
related to dripline. Dripline is specific to only the outer edge of the tree canopy, whereas tree 
canopy encompasses everything in between. 
T ree canopy cover, effective: A definition for effective tree canopy cover is reguired to 
distinguish it from actual tree canopy cover. E ffective tree canopy cover has specific 
requirements for measurement in Section 10 o f the Urban Forestry Manual. For example, 
preserving existing trees is given double tree canopy credit compared to planting new trees. 
Therefore, effective tree canopy cover is no t the same as actual tree canopy. 
T ree Care Industry Standards: T ree care industry standards are defined using the American 
Na tional Standard Institute (ANSI) standards for tree care operations. ANSI standards outline 
accepted practices for planting, pruning and maintenance o f trees. ANSI standards are 
incorporated by reference rather than explaining the standards in detail. 
T ree removal: T he existing definition o f tree removal is retained. 
Understory tree: This definition is reguired for Section 10 o f the Urban Forestry Manual to 
allow for the planting o f trees beneath the canopies of larger trees when reguired for 
constrained sites . 
24 
City of Tigard Urban Forestry Code RcYisiom I \'olumc II I 2H 
Code Amendments 
t "Tree" A wood~ . perenrual plant f . o ten wtth one . dommant trunk th . e capactty to 
achieve a manue height greater than 16 feet and primarily referred to as a tree in 
scientific literature. },. standing woody plant, or group of such, having a trunl< 
which is two inches or mme in: caliper siz;e when measmed fom feet from the 
ground. 
1l.._ "Tree Canopy" - The area above ground which is covered by the trunk branches 
and foliage of a tree or group of trees ' crowns. 
y_,_ "Tree Canopy Cover Effective" A formula detailed in Chapter 18.790 and the 
that will be f tree canopy . . 
the amount o~ ·eserving extstmg Manual used to calcula~ any oombinauon of ~~nus tree canonv Urban Forcstcy . lot or ttact throug 1 b formula grants d and grants 
. d t a gtven ncra t e .eserve I 
ptOYidoor . new trees. In gc f trees that a.e p anony of new y 
tl:l:O' and nlan~O OXi"ing tree canonte onrojected mature tree e credit based on credit based on t 
additional tree canop~ 
planted trees. 
':;'lL. "Tree Care Industty Standards" - Generally accepted industry standards for tree 
care practices detailed in the most current version of the American National 
Standards Institute (ANSI) A300 Standards for Tree Care Operations. In addition 
tree care industry standards shall include adherence to all applicable rules and 
regulations for the completion of any tree care operation. 
x,_ "Tree Removal" - The cutting or removing of 50 percent (50%) or more of a 
crown trunk or root system of a tree or an~ action which results in the loss of 
aesthetic or physiological viability or causes the tree to fall or be in immediate 
danger of fa lling. 
~ "Understory Tree" - Any tree that is adapted to grow and complete its lifecycle 
within the shade and beneath the canopy of another tree. 
Renumber definitions 171-181 
25 
City o f Tigard Urban Fores try Code ReYisions I Volume II I 29 
Commentary 
18.120.030 Meaning of Specific Words and Terms 
Four new figures are added to the end of the chapter where existing figures for definitions are 
located. The definitions of " caliper" and "DBH" can be confusing for non-arborists/ landscape 
architects, and the figures are meant to better illustrate the definitions. These figures are 
included to illustrate the definitions for "caliper" and "DBH" in Chapter 8.02 as well. 
26 
City of Tigard Urban l'orcstry \.ode Rc,-isiom I Volume II I 30 
<
 
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Commentary 
18.310 Summary of Land Use Permits 
The following revisions to permit types are included in chapter 18.310 (Summary o f Land Use 
Permits): 
2H 
• Street tree adjustments are struck because they will be handled administratively through 
Chapter 18.745; 
• Modifica tions to the urban forestry plan component of an approved land use permit will 
be allowed by Chapter 18.790 through a Type I process so reference is included in table 
18.390.1; 
• Tree removal permits are struck because they will be administered through Title 8; and 
• Discretionary urban forestry plans that are alternatives to standard urban fores try plans 
will be allowed by Chapter 18.790 through a Type III process so reference is included in 
table 18.390.1. 
CitY o t Tigard Urban Fores try Code Rc,·isions I \'olume II I 32 
Sections: 
18.310.010 
18.310.020 
18.310.010 
Code Amendments 
Chapter 18.310 
SUMMARY OF LAND U SE PERMITS 
Purpose 
Summary of Land Use Permits 
Purpose 
A. Introduction. In this development code, each land use permit or related action is processed 
by means of a generic decision-making type, e.g., Types I - IV or Limited Land Use 
D ecisions (LLD) or Expedited Land Divisions (ELD), to which it is assigned. A description 
of these decision-making procedures are summarized in Chapter 18.390. In addition, to be 
approved, each permit or related action must comply with specifically-tailored approval 
criteria, which with few exceptions are contained in Chapters 18.320 - 18.385, as well as all 
other pertinent development standards, which are found throughout this code. 
B. Purpose. The purpose of this chapter is to provide a table summarizing all land use permits 
and related actions, including cross-references to type of decision-making process, approval 
criteria and other development standards. As such, this chapter provides a "road map" for 
the permit approval process. 
18.310.020 Summary of Land Use Permits 
A. Summary Table. The table summanzmg the decision-making procedure and substantive 
approval requirements of each land use permit and related action is presented in Table 
18.310.1 below: 
29 
City of Tigard Urban Forestry Code Revisions I Volume II I 33 
Commentary 
Table 18.31 0 Summary of Land Use Permits and Related Actions 
N o changes to the Erst se t of land use permits and related actions in the table. 
_)II 
City of Tigard Urban Forestry Code Rc,·isions I \'olumc II I 34 
Code Amendments 
TABLE 18.310.1 
SUMMARY OF LAND USE PERMITS AND RELATED ACTIONS 
Land U se Permit/ Action 
Annexation 
Conditional Use 
Initial 
Major Modification 
Minor Modification 
Director's Interpretation 
Planned D evelopment 
D etailed Plan 
Site D evelopment Review 
New Construction 
Major Modification 
Minor Modifica tion 
Decision-Making 
Type 
IV 
III-HO 
III-HO 
I 
III-PC; ELD 
II 
II 
II 
I 
Approval Other Development 
Criteria Regulations 
18.320.020 
18.330.030 
18.330.030 
18.330.030 
18.350.100 
18.350.020 
18.360.090 
18.360.090 
18.360.090 
18.320 
18.330 
18.510, 18.520 
18.530 
18.340 
18.350 
18.350 
18.360 
18.360 
18.360 
31 
City of Tigard Urban Forestry Code RcYisions I Volume II I 35 
Commentary 
Table 18.31 0 Summary o f Land Use Permits and Related Actions 
Street tree adjustments are struck because they will be handled administratively through Chapter 
18.745. 
Tree removal permits are struck because they will be administered through Title 8. 
A more flexible urban fores try plan modification process is proposed in section 18.790.070 
(Modification to the Urban Foresuy Plan Component o f an Approved Land Use Permit). The 
process allows modifications through a Type I permit and is more fully described in section 
18.790.070. 
· ~ 
·'-
City of T igan.l Urban Forestry Code RcY isions I \ 'olumc II I y, 
Land Use Permit/ Action 
Variances / Adjustments 
Variances 
Development Adjustments 
Special Adjustments 
• Adjustments in Subdivisions 
TABLE 18.310.1 (Con't) 
Decision-Making 
Type 
II 
I 
2 
• Reduction of Minimum Res. Densities I 
• Access / Egress Standards Adjustments II 
• Landscaping Adjustments 
Code Amendments 
Approval Other Development 
Criteria Regulations 
18.3 70.01 O.C 
18.3 70.020.B.2 
18.370.020.C.1 
18.370 
18.370 
18.430 
18.3 70.020.C.2 18.430, 18.715 
18.370.020.C.3.b 18.705 
Existing Stteet Trees I 18.370.020.C. 4.a 18.7 45 
Nevv· Stteet Trees I 18.370.020.C.4.b 18.7 45 
• Parking Adjustments 
-Reduction in Minimum Prkg. Ratios II 
-Prkg Reduct. in New Developmts/ II 
Transit Improvements 
-Prkg Reduct. in Existing Developmts / II 
Transit Improvements 
-Increases in Maximum Parking Ratios II 
-Reduction in Bicycle Parking II 
-Alternative Parking Garage Layout II 
-Reduction in Stacking Lane Length I 
18.3 70.020.C.5.a 18.765 
18.3 70.020.C.5.b 18.765 
18.3 70.020.C.5.c 18.765 
18.3 70.020.C.5.d 18.765 
18.3 70.020.C.5.e 18.765 
18.3 70.020.C.5.f 18.765 
18.3 70.020.C.5.g 18.765 
• Sign Code Adjustments II 18.3 70.020.C.6 18.780 
• 
• 
• 
• 
Tree Removal Adjmttn:ents I 18.370.020.C.7 18.790 
Wireless Communication Facility Adj . 
-Setback from Near by Residence 
-Distance from Another Tower 
Street Improvement Adjustments 
Modification to the Urban ForestrY 
Plan Component of an Approved 
Land Use Permit 
II 
I 
II 
l 
18.3 70.020.C.8.a 
18.3 70.020.C.8.b 
18.370.020.C.9 
18.790.070.D 
City of Tigard Urban Forestry Code RcYisions I Volume II I 37 
18.798 
18.798 
18.810 
18.790 
33 
Commentary 
Table 18.31 0 Summary o f Land Use Permits and Related .Actions 
The discretionary urban fores try plan review option is an alternative to meeting the clear and 
objective effective canopy requirements in chapter 18.790. An applicant could make their case 
at a public hearing in front o f Planning Commission or the hearings o fficer about how their 
proposal is an adequate substitute for the functions and values o therwise provided by trees . 
The review body (Planning Commission or hearings o fficer) will depend on whether there is a 
concurrent Type III review. For example, if an applicant for a Planned D evelopment (Typ e III 
Planning Commission review) chooses to receive a discretionary urban fores try plan review, the 
review body will be the Planning Commission . H owever, if an applicant for a Conditional Use 
Permit (Type III hearings officer review) chooses to receive a discretionary urban fores try plan 
review, the review body will be the hearings o fficer. Finally, if an applicant does no t have a 
concurrent Type III review (e.g. Subdivision, Minor Land Partition, etc.), yet chooses to receive 
a discretionary urban fores try plan review, the review body will be the hearings o fficer. 
The discretionary urban fores try plan review process is described more fully in section 
18.790.040. 
34 
Ci ty of TiganJ Urban Fores try Code Re,·isiom I Volume II I 38 
Zoning Map / Text Amendments 
Legislative 
Quasi-Judicial 
Miscellaneous Permits 
Accessory Residential Units 
18.710 
Historic Overlay 
• Historic Overlay Designation 
IV 
III-PC 
I 
III-PC 
• Removal Historic Overlay D esignation III-PC 
• Exterior Alteration in HO District II 
• New Construction in HO District II 
• Demolition in HO District II 
Home Occupations 
• Type I I 
• Type II II 
Nonconforming Use Confirmation I 
Disl:retiQna~ Urban Em:estQ;: Elan III-PC III-HO 
Review 
Code Amendments 
Comprehensive Plan 
18.380.Q30.B 
18.380 
18.380 
Development Standards in 
18.740.040.A 18.740 
18.740.040.B 18.740 
18.740.040.C 18.740 
18.740.040.D 18.740 
18.740.040.E 18.740 
18.7 42.040.A 18.742 
18.742.050.A 18.742 
18.760.020.A 18.760 
18.790.040.C 18.790 
35 
City of Tigard Urban Forestry Code RcYisions I Volume II I 39 
Commentary 
Table 18.310 Summary of Land Use Permits and Related Actions 
Tree removal permits are struck because they will be administered through Title 8. 
_)(, 
City ofTigord Urbon Forestry Code Rc,· isions I Volume II I 40 
Code Amendments 
TABLE 18.310.1 (Con't.) 
Land Use Permit/ Action 
Sensitive Lands 
• Within 100-Year Flood Plain 
• With Excessive Slopes 
• Within Drainage Ways 
• Within Wetlands 
Signs 
• Existing 
Each 
• Modification of Existing 
• Temporary 
Temporary Uses 
• Seasonal/Special Events 
• E mergency 
• Temporary Sales Office/ Home 
• Temporary Building 
Ded sion-Making 
Type 
I, III-HO 
I, II, III-H03 
I, II, III-H03 
II, III-H03 
I 
I 
I 
I 
I 
I 
I 
Approval Other Development 
Criteria Regulations 
18.775.020.E 4, 18.775.070.B 18.775 
18.775.020.E 4, 18.775.070.C 18.775 
18.775.020.E\ 18.775.070.D 18.775 
18.775.070.E 18.775 
{Development Standards for 
{Sign Type, per 18.780 
18.780.100 
18.785.040.A 18.785 
18. 785.040.B 18.785 
18. 785.040.C 18.785 
18. 785.040.D 18.785 
Tree Removal I 18.790.050.A 18.790 
Land Division 
Lot Line Adjustment I 18.410.040 18.410 
Land Partition II, ELD 18.420.050 18.420 
Subdivisions 
• Without Planned Development II, ELD 18.430.070 18.430 
• With Planned Development III-PC, ELD 18.430.070 18.430, 18.350 
18.350.100 
Special kind of decision: Type I if not appealed, Type II if appealed by applicant. Because of 
recent Oregon case law, appeal goes directly to City Council. 
2 Addressed concurrently with subdivision review. 
3 
4 
Can be reviewed as either Type II or IliA, depending on criteria in 18.775.015.D and E . 
Type I procedures are reviewed with criteria of Section 18.775.020.E. Type II and III 
procedures are reviewed with criteria of Section 18.77 5.070.B. 
KEY: 
Type I: Ministerial Review (18.390.030) 
Type II: Quasi-Judicial Review by Director (18.390.040) 
Type III-HO: Quasi-Judicial by Hearings Officer (18.390.050) 
Type III-PC: Quasi-Judicial by Planning Commission (18.390.050) 
Type IV: Legislative (18.390.060) 
LLD: Linuted Land Use Decision (18.390.070) 
ELD: Expedited Land Division (18.390.070) 
City of Tigard Urban Forestry Code Revisions I Volume II I 41 
37 
Commentary 
18.330.030 Approval Standards and Conditions of Approval 
T he Conditional Use Permits (CUPs) have been, and will continue to be required to meet the 
requirements of Chapter 18.745 (Landscaping and Screening) and Chapter 18.790 (Urban 
Forestry Plan). Explicit references to these requirements are made in the approval standards 
section of the conditional use chapter. 
:>s 
Ci ty of Tigard Urban l'ore>try Code Rc,·i>ion> I \'olumc II I 42 
Code Amendments 
Sections: 
18.330.010 
18.330.020 
18.330.030 
18.330.040 
18.330.050 
18.330.010 
[No change.] 
18.330.020 
[No change.] 
18.330.030 
Purpose 
Approval Process 
Chapter 18.330 
CONDITIONAL USE 
Approval Standards and Conditions of Approval 
Additional Submission Requirements 
Additional Development Standards for Conditional Use T ypes 
Purpose 
Approval Process 
Approval Standards and Conditions of Approval 
A. Approval standards. The Hearings Officer shall approve, approve with conditions, or deny 
an application for a conditional use or to enlarge or alter a conditional use based on findings 
of fact with respect to each of the following criteria: 
1. The site size and dimensions provide adequate area for the needs of the proposed use; 
2. The impacts of the proposed use of the site can be accommodated considering size, 
shape, location, topography, and natural features; 
3. All required public facilities have adequate capacity to serve the proposal; 
4. The applicable requirements of the zoning district are met except as modified by this 
chapter; 
5. The applicable requirements of 18.330.050; and 
6. The supplementary requirements set forth in other chapters of this code including but 
not limited to Chapter 18.780, Signs, Chapter 18.745 Landscaping and Screening 
Chapter 18.790 Urban Forestry Plan and Chapter 18.360, Site Development Review, if 
applicable, are met. 
B. lNo change.] 
39 
City of Tigard Urban Forestry Code Re\'isions I Volume II I 43 
Commentary 
18.330.040 Additional Submission Requirements 
The Conditional Use Permits (CUPs) have been, and will continue to be requil_.ed to meet the 
requirements o f Chapter 18.790 (Urban Forestry Plan). Explicit reference to the submission 
requirements for an urban fores try plan has been made. 
4(1 
City of Tigard Urban l'orc>try Cock Rc,·i>iom I \'olumc II I 44 
Code Amendments 
18.330.040 Additional Submission Requirements 
A . Additional submission requirem ents. In addition to the submission requirements required in 
Chapter 18.390, D ecision-Making Procedures, an application for conditional use approval 
must include the following additional information in graphic, tabular and/ or narrative form. 
T he Director shall provide a list o f the specific information to be included in each o f the 
following: 
1. Existing site conditions; 
2. A site plan; 
3. A grading plan; 
4. A landscape plan; 
5. An urban fores trv olan consistent with Chanter 18.790: 
~g. Architectural elevations of all structures; and 
61. A copy o f all existing and proposed res trictions or covenants. 
41 
City of Tigard Urban Forestry Code Revisions I Volume II I 45 
Commentary 
18.330.050 Additional D evelopment Standards for Conditional Use Typ es 
Conditional uses have specific requirements based on the type of use. T he parking and storage 
setback requirement for motor vehicle servicing and repair has been increased from 5 to 6 feet 
so that required parking lo t trees can be planted within the perimeter setback. 
T he Urban Fores try Manual consists o f administrative mles to implement the details of the 
urban fores try related code provisions in Title 8, T itle 18 and o ther applicable titles in the Tigard 
Municipal Code. Section 13 o f the Urban Fores try Manual requires parking lo t trees to be 
planted in loca tions with minimum dimensions o f 6 feet by 6 feet, so the amendment is intended 
to be consistent with the parking lo t tree requirements. 
The screening requirements are found in Section 18.745.050, so the existing scrivener's error has 
been corrected. 
42 
City of T igard Urban l'orcstry Code RL:\·isions I \ 'olumc II I -lC. 
18.330.050 
Code Amendments 
Additional Development Standards for Conditional Use Types 
A. Concurrent variance application(s). A conditional use permit shall not grant variances to the 
regulations otherwise prescribed by this title. A variance application(s) may be filed in 
conjunction with the conditional use application and both applications may be heard at the 
same hearing. 
B. Additional development standards. The additional dimensional requirements and approval 
standards for conditional use are as follows: 
1. Adult E ntertainment: 
[No change.] 
2. Motor Vehicle Servicing and Repair: 
a. Setbacks: 
(i) A six .fure-foot perimeter setback shall surround all outdoor parking and storage 
areas; 
(ii) Buffer screening shall be provided along the perimeter of all outdoor parking and 
storage areas as required in Section 18.7 45.04~0; and 
(iii) All repair work shall be performed indoors . 
3. through 16. 
[No change.] 
43 
City of Tigard Urban Fores try Code RcYisions I Volume II I 47 
Commentary 
18.330.050 .A dditional D evelopment Standards for Conditional Use Types 
Conditional uses have specific requirements based on the type o f use. T he parking setback 
requil:ement for non-accessory parking has been increased from 5 to 6 feet so that required 
parking lo t trees can be planted withil1 the perilneter setback. 
The Urban Forestry Manual consists of administrative rules to implem ent the details of the 
urban fores try related code provisions in Title 8, Title 18 and o ther applicable titles in the Tigard 
Municipal Code. Section 13 of the Urban Fores try Manual requires parking lot trees to be 
planted in locations with minimum din1ensions o f 6 feet by 6 feet, so the amendment is intended 
to be consistent with the parking lo t tree requirements. 
44 
City of 'J"iganl Urban l'o rc,try Code Re,·i,iom I Volume II I 48 
Code Amendments 
17. Non-Accessory Parking: 
a. Minimum lot size shall be 5,000 square feet; 
b. Minimum setbacks: for structures: shall be those of the applicable zone; for parking 
area: .fWe six feet around perimeter of paved area for landscaping and screening 
purposes; 
c. Height limitation shall be that of the applicable zone; 
d. Off-street parking requirements shall be in accordance with Chapter 18.765; and 
e. Screening shall be in accordance with Chapter 18.7 45. 
18. through 20. 
_[No change.] 
45 
City of Tigard Urban Forestry Code Re,-isions I Volume II I 49 
Commentary 
18.350.040 Concept Plan Submission Requirements 
Planned developments (PDs) have been, and will continue to be required to meet the 
requirements o f Chap ter 18.790 (Urban Forestry Plan). 
In addition, among the stated purposes ofPD s (18.350.010) is the preservation o f natural 
resources, with tree preserva tion called out specifically. PDs are typically approved through a 
two-step process with a conceptual plan approval followed by a detailed plan approval by 
Planning Commission. T herefore, the submittal of an urban fores try plan during the conceptual 
stage will help the Planning Commission implement the purpose o f PDs during the conceptual 
phase o f approval. 
+6 
CitY of T igard Urban l'orcsrry Code Re,· isions I Volume II I 511 
Sections: 
18.350.010 
18.350.020 
18.350.030 
18.350.040 
18.350.050 
18.350.060 
18.350.070 
18.350.010 
Purpose 
Process 
Chapter 18.350 
PLANNED DEVELOPMENTS 
Administrative Provisions 
Concept Plan Submission Requirements 
Concept Plan Approval Criteria 
Detailed Development Plan Submission Requirements 
Detailed Development Plan Approval Criteria 
Purpose 
[No change.) 
18.350.020 Process 
[No change.] 
18.350.030 Administrative Provisions 
[No change.] 
18.350.040 Concept Plan Submission Requirements 
A. [No change.) 
Code Amendments 
B. Additional information. In addition to the general information described in Subsection A 
above, the concept plan, data, and narrative shall include the following information, the 
detailed content of which can be obtained from the Director: 
1. Existing site conditions; 
2. A site concept including the types of proposed land uses and structures, including 
housing types, and their general arrangement on the site; 
3. A grading concept; 
4. A landscape concept indicating a percentage range for the amount of proposed open 
space and landscaping, and general location and types of proposed open space(s); 
5. An urban forestry plan consistent with Chapter 18.790: 
5~. Parking concept; 
47 
City of Tigard Urban Forestry Code Re,·isions I Volume ll I 51 
Commentary 
18.350.040 Concept Plan Submission Requirements 
Renumbering of submission requirements continued. 
18.350.050 Concept Plan Approval Criteria 
Since tree preserva tion is called out specifically as one of the purposes of PDs, and urban 
fo res try plans are required during the conceptual stage, the concept plan approval criteria should 
include tree presetvation. 
T he word " significant" is removed because the word is undefined, and could be misconstrued as 
applying only to "significant tree groves". The intent o f the approval criterion is to consider the 
presetv ation o f any tree or natural resource as part o f PDs. 
48 
City of T igard Urban Forc>try Code RcYi>ion> I \'olumc 11 I 52 
Code Amendments 
61- A sign concept; 
:t-,a. A streets and utility concept; and 
82,. Structure setback and development standards concept, including the proposed residential 
density target if applicable. 
C. Allowable uses. 
[No change.] 
18.350.050 Concept Plan Approval Criteria 
A. The concept plan may be approved by the Commission only if all of the following criteria 
are met: 
1. The concept plan includes specific designations on the concept map for areas of open 
space, and describes their intended level of use, how they relate to other proposed uses 
on the site, and how they protect natural features of the site. 
2. The concept plan identifies areas of significant trees and other natural resources, if any, 
and identifies methods for their maximized protection, preservation, and/ or 
management. 
3. The concept plan identifies how the future development will integrate into the existing 
neighborhood, either through compatible street layout, architectural style, housing type, 
or by providing a transition between the existing neighborhood and the project with 
compatible development or open space buffers. 
4. The concept plan identifies methods for promoting walkability or transit ridership, such 
methods may include separated parking bays, off street walking paths, shorter pedestrian 
routes than vehicular routes, linkages to or other provisions for bus stops, etc. 
5. The concept plan identifies the proposed uses, and their general arrangement on site. In 
the case of projects that include a residential component, housing type, unit density, or 
generalized lot sizes shall be shown in relation to their proposed location on site. 
6. The concept plan must demonstrate that development of the property pursuant to the 
plan results in development that has significant advantages over a standard development. 
A concept plan has a significant advantage if it provides development consistent with the 
general purpose of the zone in which it is located at overall densities consistent with the 
zone, while protecting natural features or providing additional amenities or features not 
otherwise available that enhance the development project or the neighborhood. (Ord. 
06-16) 
49 
City of Tigard Urban Fores try Code Revisions I Volume II I 53 
Commentary 
18.350.060 D etailed D evelopment Plan Submission Requirements 
A scrivener's error has been corrected to reference Title 18 instead of Title 3. 
The detailed development plan submission requirem ents have been revised to require contour 
elevations o f 1 foot instead of 2 to 5 feet consistent with typical engineering practice and 
available technology. For tree preserva tion , accuracy in grading plans is required because a 
1-foot difference in a cut o r fill could cause a tree to die or become hazardous. 
The Urban Forestry Manual consists o f adminis trative rules to implement the details of the 
urban fores try related code provisions in Title 8, T itle 18 and o ther applicable titles in the T igard 
Municipal Code. Contours o f 1 foo t are required by Section 10 o f the Urban Fores try Manual in 
the tree preservation and removal site plan, so 1 foot contours for PDs is consistent. T he 
phrase "unless o therwise approved" is included because there will be many cases where such 
detail is no t necessary or will make the plans illegible. 
A development schedule is required for PD s, and an important element to include is the timing 
of landscaping. The landscaping phase is important to tree preservation (irriga tion installation, 
etc.) and to insure required trees are planted at appropriate times o f year. 
18.350.070 D etailed D evelopment Plan Approval Criteria 
No changes to the detailed development plan approval criteria. 
50 
City of Tigard Urban Forc>try Code Rc,·i>iom I Volume II I 54 
Code Amendments 
18.350.060 D etailed D evelopment Plan Submission Requirements 
A. General submission requirements. The applicant shall submit an application containing all of 
the general information required for a Type III-PC procedure, as governed by Section 
18.390.050, the additional information required by Section 18.350.040.B and the approval 
criteria under Section .l..M.350.070. 
B. Additional information. In addition to the general information described in subsection A 
above, the detailed development plan, data, and narrative shall include the following 
in forma cion: 
1. Contour intervals of one foot unless othetwise approved by the Director two to five 
feet, depending on slope gt'adients, and spot elevations at breaks in grade, along drainage 
channels or swales, and at selected points, as needed. 
2. A specific development schedule indicating the approximate dates of construction 
activity, including demolition, tree protection installation, tree removal, ground breaking, 
grading, public improvements, ftftd-building construction and landscaping for each 
phase. 
3. A copy of all existing and/ or proposed restrictions or covenants. 
C. [No change.] 
18.350.070 Detailed Development Plan Approval Criteria 
[No change.] 
51 
City o f Tigard Urban Forestry Code Revisions I Volume II I 55 
Con'lmentary 
18.360 SITE D EVELOPMENT REVIEW 
Site development reviews (SDRs) have been, and will continue to be required to meet the 
requirements of Chapter 18.790 (Urban Forestry Plan). 
18.360.070 Submission Requirements 
Explicit reference to the urban fores try plan requirement is made in the submission requirement 
section. 
52 
City of TiganJ Urban l'orc>lry Code Rc.,-isions I \ 'olumc II I 56 
Code Amendments 
Chapter 18.360 
Sections: 
18.360.010 
18.360.020 
18.360.030 
18.360.040 
18.360.050 
18.360.060 
18.360.070 
18.360.080 
18.360.090 
SITE DEVELOPMENT REVIEW 
Purpose 
Applicability of Provisions 
Approval Process 
Bonding and Assurances 
Major Modification(s) to Approved Plans or Existing Development 
Minor Modification(s) to Approved Plans or Existing Development 
Submission Requirements 
Exceptions to Standards 
Approval Criteria 
18.360.010 -18.360.060 
[No change.] 
18.360.070 Submission Requirements 
A. General submission requirements. The applicant shall submit an application containing all of 
the general information required for a Type II procedure, as governed by Section 
18.390.040. 
B. Additional information. In addition to the submission requirements required in Chapter 
18.390, Decision-Making Procedures, an application for the conceptual development plan 
must include the following additional information in graphic, tabular and/ or narrative form. 
The Director shall provide a list of the specific information to be included in each of the 
following: 
1. An existing site conditions analysis; 
2. A site plan; 
3. A grading plan; 
4. A landscape plan; 
5. An urban forestry plan consistent with Chapter 18.790; 
-3~. Architectural elevations of all structures; and 
61. A copy of all existing and proposed restrictions or covenants. 
18.360.080 Exceptions to Standards 
[No change.] 
53 
City of Tigard Urban Forestry Code Re,·isions I Volume II I 57 
Commentary 
18.360.090 Approval Criteria 
T he reference to "preserve trees to the extent possible" in Chapter 18.790 has been struck since 
the statement does not describe the requirements in Chapter 18.790. A cross reference to 
Chapter 18.790 has already been provided in Section 18.360.070. 
A cross reference stating that landscaping is required to be designed in accordance with both 
Chapter 18.7 45 and Chapter 18.790 has been added. Both chapters have specific landscaping 
requirements. 
54 
City of Tigard Urban i'orcstry Code Re,·isions I \'olume II I SH 
Code Amendments 
18.360.090 Approval Criteria 
A. Approval criteria. The Director shall make a finding with respect to each of the following 
criteria when approving, approving with conditions, or denying an application: 
1. Compliance with all of the applicable requirements of this title including Chapter 18.810, 
Street and Utility Standards; 
2. Relationship to the natural and physical environment: 
a. Buildings shall be: 
(1) Located to preserve eX1s tlng u·ees, topography and natural drainage where 
possible based upon existing site conditions; 
(2) Located in areas not subject to ground slumping or sliding; 
(3) Located to provide adequate distance between adjoining buildings for adequate 
light, air circulation, and frre-fighting; and 
(4) Oriented with consideration for sun and wind. 
b . Trees shall be preser.red to the extent possible. Replacement of trees is subject to the 
requirements o f Chapter 18.790, Tree Removal. 
e,Q. Innovative methods and techniques to reduce impacts to site hydrology and fish and 
wildlife habitat shall be considered based on surface water drainage patterns, 
identified per Section 18.810.1 OO.A.3. and the City of Tigard "Significant Habitat 
Areas Map." Methods and techniques for consideration may include, but are not 
limited to the following: 
(1) through (7) [No change.] 
3. through 11. [No change.] 
12. Landscaping: 
a. All landscaping shall be designed in accordance with the requirements set forth in 
Chapter 18.745 and 18.790; 
b. In addition to the open space and recreation area requirements of Subsections A.5 
and 6 above, a minimum of 20% of the gross area including parking, loading and 
service areas shall be landscaped; and 
c. A minimum of 15% of the gross site area shall be landscaped. 
13. through 15. [No change.] 
55 
City of Tigard Urban Forestry Code Re,·isiom I Volume II I 59 
Commentary 
18.370.020 Adjustments 
The existing adjustments to allow existing trees to be used as street trees, to modify the street 
tree planting ·requirements, and to allow setback adjustment for tree preservation have been 
struck. 
T he adjustment to use an existing tree as a street tree should be allowed without paying for an 
adjustment. Requiring someone to pay to preserve a tree is a disincentive to preservation . The 
criteria for using an existing tree as a street tree are included in Chapter 18.745.040.A.5. 
Modification o f street tree requirements is struck because the existing and proposed code allows 
wide flexibility to vary the placement o f street trees to avoid sa fety conflicts and space 
constraints. In addition , staff canno t recall any cases where this adjustment has been used. 
sr, 
CitY of Tigard Urban l'orcstry Code ReYisions I \'olumc II I 60 
Sections: 
Chapter 18.370 
VARIANCES AND ADJUSTMENTS 
18.370.010 
18.370.020 
Variances 
Adjustments 
18.370.010 Variances 
[No change.] 
18.370.020 Adjustments 
A. [No change.] 
B. [No change.] 
C. Special adjustments. 
1-5. [No change.] 
6. }Ldjustments to landscaping requi:rements (Chapter 18.7 45) . 
Code Amendments 
a. Adjustm:ent to use of existing tfees as stfeet ttees. By means of a Type I pwcedure, 
as governed by Section 18.390.030, the Difector shall approve, appwve v.-ith 
conditions, of deny a fequest fm the use of existing ttees to meet the stteet tfee 
fequi:ren1ents in Section 18.745.030 pro .·iding there has been no cutting and fi.ll:in:g 
around the tree during consttuction which may lead to its loss, unless the folio'W1:ng 
can be demonsttated: 
(1) The gwund within the dt'ip l:ifle is altered InCt'ely for drainage purposes; and 
/')\ T .. ,_...,. .. ...,. h r. ro t.. ,-.. ,.,.. .,. ...... +-l .. ..-.. 4- 4-l-.. r.. ,.., ,4- ...... ,.. C::ll .. ...- ~ 11 ....... ..-.. +- .....J...,...........,...,. _._r-, +-h r. .., ,..,.,-.. 4-r. ...,.,. .... ,..1 ,..,- .,. ~ ]] -.. ,-.. 4- ,.......,. ,, ....,;-,. 
\i:...j ~1... \...-il.J.~ IJ\..- 0~1.\.JW.l ..L L..L.I.ClL L.l-.1.\...- '-'UL V.J... .L.J.....U._ WLLL J...lVL Uil.J..l_.l(;l 5 \..- L..LJ.\...- .LVVLV a.J...LU W..LLL .ll.VL \...-au ,::n •. .-
the ttee to die. 
b. 
/ 1 \ T C .. t... ...... l r... ...... .-..+-~ ....... ..... ........ C_ ..... .................... .-... r.. .......... ...-1 ...... ............ ,.,.. , ....... ,.,.ld ___ r..r..,.,. .... ..o. _.-... ...-,..+-..o.-+-~.n.l_ ........ ,. ........ l .... t ...... ........... n _ _ ,,.. ,.~ ..... l-.. ..... ,. ~ ~ ..... ..... ~ ...... ~ \ .1 ) .Ll. L.ll.'-.. H .. H ..... tl.UVJ.l. V.L a l:-'.1.'-'J:-'VU\....U U..\..A ..- VVVU.l.U \....aU- 0 \.... I_JVL\ •.• .l..LLLa..L 1-'.LVU.l\ •. - J...Ll...:J W.lLJ.J. \....- A .l0U..U 5 
utility lines; 
( '1 \ TC ~~~ ~ '"··~~ .. . ~ .. lrl ~~ .. ~~ .. ; ~ .. ~ I~~ ~~ ··~~~ ~ ~··~hi ~~AT ~ ·· \ L..) .LJ. Ll.lL- LL'--\.... W\.JUJ.U \....tlU-0\.... Y.l.:JU-a.l \.....1\...-Q.Ltl.J..l\....\.... 1-'.LVlJ.l\....,l.l.l.:J ' V.L 
/ 'l \ TC ..... t .. ,... .......... ~ ..... ..... ....... ......... .....1 ............. .... ................. ....... ................ ~4 .... ... ...- ... t .... ~ ..... t.... .... ....... ....... 1 .... ........... .... ....... ............ ........... ............ ,... \J) II LTn::..Ll.,:.. ~0 l.IUT..- -lt UL'-:fUlll.\:..:. .:Jpa\,....\:,.:. lli VVl.ll\:..:..li T..V _t'l.Lll.IT.. 0Ll.\.....\.....T.. T...I.L\:..:.0, 
57 
City of Tigard Urban Fores try Code Revisions I Volume 11 I 61 
Commentary 
18.370.020 Adjustments 
Section 18.790.050 (Flexible Standards for Planting and Preservation) allows for adjustments to 
setback requirements (and o ther development standards) to be reviewed concurrently with main 
land use review type. Requiring an additional process and payment of a fee to preserve a tree is 
a disincentive to preservation. 
58 
City of Tigard Urban l'orestry Code Rc,·isions I Volume II I 62 
Code Amendments 
Renumber 7-8 
9. Adjustments to setbacks to reduce tree removal (Chapter 18. 790). By means of a Type I 
procedure, as governed by Section 18.390.030, the Director may grant a modification 
from applicable setbaclc requirements of this Code for the purpose of pt-eserving a tree 
or trees on the site of proposed development. Such modification may reduce the 
required setback by up to 50%, but shall not be tnore than is necessary for the 
preservation of trees on the site. The setbaclc modification described in this section shall 
supersede any special setback requirements or exceptions set out else~here in this title, 
in:eluding but not limited to Chapter 18.730, except Section 18.730.040. 
Renumber 10-11 
59 
City of Tigard Urban Forestry Code Revisions I Volume II I 63 
Commentary 
18.390.020 D escription o f D ecision-Making Procedures 
T he following revisions to permit types are included in table 18.390.1 (Decision Making 
Procedures): 
60 
• Street tree adjustments are struck because they will be handled administratively through 
Chapter 18.745; 
• Modifications to the urban fores try plan component o f an approved land use permit will 
be allowed by Chapter 18.790 through a Type I process so reference is included in table 
18.390.1; 
• Tree removal permits are struck because they will be administered through Title 8; and 
• Discretionary urban forestry plans that are alternatives to standard urban fores try plans 
will be allowed by Chapter 18.790 through a Type III process so reference is included in 
table 18.390.1. 
City of T igard Urban l;orcstry Cndc RcYisiom I Volume II I 64 
Code Amendments 
Chapter 18.390 
Sections: 
18.390.010 
18.390.020 
18.390.030 
18.390.040 
18.390.050 
18.390.060 
18.390.070 
18.390.080 
18.390.010 
[No change.] 
18.390.020 
DECISION-MAKING PROCEDURES 
Purpose 
Description of Decision-Making Procedures 
Type I Procedure 
Type II Procedure 
Type III Procedure 
Type IV Procedure 
Special Procedures 
General Provisions 
Purpose 
Description of Decision-Making Procedures 
A. [No change.] 
B. [No change.] 
C. Summary of permits by decision-making procedure type. Table 18.390.1 summarizes the 
various land use permits by the type of decision-making procedure. 
TABLE 18.390.1 
SUMMARY OF PERMITS BY TYPE OF DECISION-MAKING PROCEDURE 
Type 
I (18.390.030) 
Permit/Land Cross-Reference( s) 
Accessory Residential Units 18.710 
Development Adjustments 18.370.020.B.2 
Design Review Compliance Letter (Track 1) 18.610 
Home Occupation/ Type I 18.742 
Landscaping Adjustments 
Existing Street Trees 18.370.020.C.4.a; 18.745 
New Street Trees 18.370.020.C.4 .b; 18.7 45 
Lot Line Adjustment 
Minimum Residential Density Adjustment 
City of Tigard Urban Forestry Code Re,-isions I Volume II I 65 
18.410.040 
18.3 70.020.C.2; 18.430; 
18.715 
61 
Commentary 
18.390.020 D escription of D ecision-Making Procedures 
Tree removal permit requirements are struck from Title 18 and included in the consolidated 
Title 8 provisions that address tree permit requirements when not associated with an urban 
forestry plan per Chapter 18.790. 
A new Type I process is es tablished for major modifications to the urban forestry plan 
component o f an approved land use permit. Type I modifications are performed as a staff level 
decision and do not require notice o f the surrounding neighbors. 
T he full process for a Modification to the Urban Forestry Plan Component of an Approved 
Land Use Pennit is included in Section 18.790.070. 
62 
C:ity of Tigard Urban l'ore>try Code Rc,·isions I \' olumc II I (,(, 
Type 
II (18.390.040) 
Code Amendments 
Nonconforming Use Confirmation 
Parking Adjustments 
- Reduction of Minimum Parking Ratios 
in Existing Developments/ Transit Imp. 
- Reduction in Stacking Lane Length 
Signs 
_ New 
_ Existing 
Site Development/ Minor Modification 
Temporaty Uses 
- E mergency Uses 
- Seasonal/Special Uses 
- Temporaty Building 
- Temporaty Sales Office/ Home 
Urban Forestry Plan 
18.385.030.A; 18.760 
18.3 70.020.C.5.c; 18.7 65 
18.3 70.020.C.5.g; 18.7 65 
18.780 
18.780 
18.360.090 
18.785 
18.785 
18.785 
18.765 
- Modification to the Urban 18.790.070 
Forestry Plan Component 
of an Approved Land Use Permit 
Tree Removal 
Removal Adjustment 18.370.020.C.7; 18.790 
Removal Permit 18.790 
Wireless Communications Facilities --
Setback from Other Towers 
Conditional Use/Minor Modification 
Permit/Land 
Access/Egress Adjustment 
Downtown D esign Administrative Review 
(Track 2) 
Historic Overlay 
- Exterior Alternation 
- New Construction 
- Demolition 
Home Occupation/ Type II 
City of Tigard Urban Forestry Code Revisions I Volume II I 67 
18.370.040.C.8.b; 18.798 
18.330.030 
Cross-Reference( s) 
18.370.020.C.3.b 
18.610 
18.740 
18.740 
18.740 
18.742 
63 
Commentary 
18.390.020 D escription of D ecision-Making Procedures 
A new Type III process is es tablished for a discretionary urban fores try plan review option as an 
alternative to meeting the clear and objective effective canopy requirements. Type III 
modifications require notice o f the surrounding neighbors, and a hearing in front of Planning 
Commission or the hearings o fficer. This option could allow people to utilize green fea tures 
such as green roo fs, green streets, etc. as a substitute for the environmental benefits provided by 
trees. The full process for a discretionary urban fores try plan review option is included in 
Section 18.790.040. 
The review body (Planning Commission or hearings officer) will depend on whether there is a 
concurrent Type III review. For example, if an applicant for a Planned D evelopment (T ype III 
Planning Commission review) chooses to request a discretionary urban forestry plan review, the 
review body will be the Planning Commission. H owever, if an applicant for a Conditional Use 
Permit (Type III hearings officer review) chooses to request a discretionary urban forestry plan 
review, the review body will be the hearings officer. Finally, if an applicant does not have a 
concurrent Type III review (e .g. Subdivision , Minor Land Partition, etc.), yet chooses to reques t 
a discretionary urban foresuy plan review, the review body will be the hearings o fficer. 
64 
City of Tigard Urban Fore>try Code Re,·i>iom I \'olume II I 6H 
Type 
IliA (18.390.050) 
(Hearings Officer) 
Permit/Land 
Code Amendments 
Cross-Reference( s) 
Land Partitions 1 
Parking Adjustments 
- Reduction in Minimum Parking Ratios 
- Reduction of Minimum Parking Ratios 
in New Developments / Transit Imp 
- Increase in Maximum Parking Ratios 
- Reduction in Bicycle Parking 
- Alternate Parking Garage Layout 
Sensitive Lands Permits 
- In 25% + Slope 
- Within Drainageways 
- Within Wetlands1 
Sign Code Adjustment 
Site Development Review 
- New Construction 
- Major Modification 
18.420.050 
18.3 70.020.C.5.a; 18.7 65 
18.370.020.C.5.b; 18.765 
18.3 70.020.C.5.d; 18.7 65 
18.370.020.C.5.e; 18.765 
18.370.020.C.5.f; 18.765 
18.775 
18.775 
18.775 
18.3 70.020.C.6; 18.780 
18.360.090 
18.360.090 
Subdivision Without Planned Developmene 18.430.070 
Variances 
Wireless Communication Facilities--
Adjustment to Setback from Residences 
Appeals to Hearings Officer 
Conditional Use 
- Initial 
- Major Modification 
Sensitive Lands 
- Within 100-Year Floodplain 
- In 25% + Slope1 
- Within Drainageways 1 
- Within Wetlands 1 
Urban Forestry Plan 
18.3 70.01 o.c 
18.3 70.020.C.8.a; 18.798 
18.390.040.G 
18.330.030 
18.330.030 
18.775 
18.775 
18.775 
18.775 
- Discretionary Urban Forestry Plan Review 18.790.040 
Option 
City of T igard Urban Forestry Code Revisions I Volume II I 69 
65 
Commentary 
18.390.020 D escription o f D ecision-Making Procedures 
r\ new Type III process is es tablished for a discretionary urban fores try plan review option as an 
alternative to meeting the clear and objective effective canopy requirements. Type III 
modifications require notice o f the surrounding neighbors , and a hearing in front of Planning 
Commission or the hearings o fficer. This option could allow people to utilize green fea tures 
such as green roo fs, green streets, etc. as a substitute for the environmental benefits provided by 
trees. The full process for a discretionary urban fores try plan review option is included in 
Section 18.790.040. 
T he review body (Planning Commission or hearings officer) will depend on whether there is a 
concurrent Type III review. For example, if an applicant for a Planned D evelopment (Type III 
Planning Commission review) chooses to request a discretionary urban forestry plan review, the 
review body will be the Planning Commission. H owever, if an applicant for a Conditional Use 
Permit (Type III hearings officer review) chooses to request a discretionary urban forestry plan 
review, the review body will be the hearings o fficer. Finally, if an applicant does not have a 
concurrent Type III review (e.g. Subdivision, Minor Land Partition, etc .) , yet chooses to request 
a discretionary urban forestry plan review, the review body will be the hearings o fficer. 
66 
Ci ty of Tigard Urban J:orcs try Code Rc,·isions I Volume 11 I 7() 
Type Permit/ Land 
Code Amendments 
Cross-Reference(s) 
IIIB (18.390.050) 
(Planning Comm.) 
Historic Overlay 
- District Overlay 
- Removal of District Overlay 
Planned Development 
- With Subdivision 
- Without Subdivision 
one Map / Text Change/ Quasi-Judicial 
Urban Forestnr Plan 
18.385.010.A; 18.740 
18.385.01 O.B; 18.7 40 
18.350.1 00; 18.430 
18.350.100 
18.380.030.B 
- Discretionary Urban Forestry Plan Review 18.790.040 
Option 
IIIC (18.390.050) Downtown Design Review (Track 3) 18.610 
(Design Review Board) 
IV (18.390.060) Annexation 18.320 
one Map/ Text Change/ Legislative 18.380.020 
1These may be processed as either Type II or III procedures, pursuant to Section 18.775.020.D 
and E. (Ord. 10-02 § 2; Ord. 09-13) 
18.390.030 through 18.390.080 
[No change.] 
City o f Tigard Urban Forestry Code Rc,·isions I Volume II I 71 
67 
Commentary 
18.530 IN D USTRIAL Z O N ING DISTRICTS 
A minor amendment is reguired to the chapter to correct a cross reference to street trees and 
caliper. 
18.530.050 Additional D evelopment Standards 
T he amendment corrects the cross reference to street trees and caliper. 
68 
City of Tigard Urban l'orcstry Code Rc,·isions I \'olumc II I 72 
Chapter 18.530 
Sections: 
18.530.010 
18.530.020 
18.530.030 
18.530.040 
18.530.050 
INDU STRIAL ZONING DISTRICTS 
Purpose 
List of Zoning Districts 
Uses 
Development Standards 
Additional Development Standards 
18.530.010 through 18.530.040 
[No change.] 
18.530.050 Additional D evelopment Standards 
A. [No change.] 
Code Amendments 
B. Reduction of lo t coverage requirements. Lot coverage may be increased from 75% to 80% as 
part of the site development review process, providing the following requirem ents are 
satisfied: 
1. T he minimum landscaping requu:em ent shall be 20% of the site. 
2. T he applicant shall meet the followi11g performance standards with regard to the 
landscaping plan approved as part o f the site development review process : 
a. Street trees, as required by Section 18.745.040.A&.+ are-tf1 shalL.be installed with a 
nllilinlum caliper of three inches fathef than the fivo inches as 111easmed at fom feet 
in he~ht; 
b. T he landscaping between a parking lo t and street proper ty line shall have a minimum 
width o f 10 feet; 
c. All applicable buffering, screening and setback requiremen ts contained in Section 
18.745 .050 shall be satisfied; 
d. T he applicant shall provide documentation of an adequate on-going maintenance 
program to ensure appropriate irrigation and maintenance of the landscape area. 
C. [No change] 
69 
City of Tigard Urban Forestry Code Revisions I Volume II I 73 
Commentary 
18.610 TIGARD DOWNTOWN DISTRICT DEVELOPMENT AND DESIGN 
STANDARDS 
For consistency purposes, minor am endments are made to this chapter to cross reference 
Chapter 18.790 (Urban Forestry Plan) in sections 18.610.01 O.F (Submittal Requirements) and 
18.610.035 (Additional Standards). 
70 
Cit} of Tigard Urban l'orcstry Code Rc,·isions I \'olumc II I 74 
Code Amendments 
Chapter 18.610 
TIGARD DOWNTOWN DISTRICT DEVELOPMENT AND DESIGN 
STANDARDS 
Sections: 
18.610.010 
18.610.015 
18.610.020 
18.610.025 
18.610.030 
18.610.035 
18.610.040 
18.610.045 
18.610.050 
Process) 
18.610.055 
18.610.060 
18.610.010 
Purpose and Procedures 
Pre-Existing Uses and Developments within the Downtown District 
Building and Site Development Standards 
Street Connectivity 
Building and Site Design Standards 
Additional Standards 
Special Requirements for Development Bordering Urban Plaza 
Exceptions to Standards 
Building and Site Design Objectives (to be used with Track 3 Approval 
Signs 
Off-Street Parking and Loading Requirements 
Purpose and Procedures 
A . through E. [No change.] 
City of 'figard Urban Forestry Code Re,-isions I Volume II I 75 
71 
Commentary 
18.610.010 Purpose and Procedures 
E xplicit reference to the urban fores try plan requirement is made in the submission requirement 
section . 
18.610.015 -18.610.030 
No changes are required to these sections as a result of the urban forestry code revisions. 
72 
City of T igard Urban Fore>try Code Re,-i,iom I \ 'olume II I 76 
Code Amendments 
F. Downtown design review submittal requirements. 
1. General Submission Requirements. The applicant shall submit an application containing 
all of the general information required for a Type II procedure, as governed by Section 
18.390.040, or for a Type III procedure, as governed by Section 18.390.050. 
2. Additional Information. In addition to the submission requirements required in Chapter 
18.390, Decision-Making Procedures, an application must include the following 
additional information in graphic, tabular and/ or narrative form. The Director shall 
provide a list of the specific information to be included in each of the following: 
a. An existing site conditions analysis; 
b. A site plan; 
c. A grading plan; 
d. A landscape plan; 
.e... An urban forestry plan consistent with Chapter 18.790. 
e.-£ Architectural elevations of all structures; and 
.fg. A copy of all existing and proposed restrictions or covenants. 
3. All drawings submitted with applications for development using Tracks 2 and 3 shall be 
stamped by a registered architect. Applications for landscaping projects only may be 
stamped by a registered landscape architect. Applications that require engineering or 
transportation reports must be stamped by the appropriate specialist. 
G. through K. [No change.] 
18.610.015 through 18.610.030 
[No change.] 
7.) 
City of Tigard Urban Forestry Code Re,·isions I Volume II I 77 
Commentary 
18.610.035 Additional Standards 
The reference to "Tree Removal" has been changed to "Urban Forestry Plan" consistent with 
the name change to Chapter 18.790. 
18.610 T IGARD D OWNTOWN DISTRICT D EVELOPMENT AND D ESIGN 
STANDARDS 
No changes to the standards in Sections 18.610.040 to 18.610.060. 
74 
City of Tigard Urban l;orcstry Code Rc,-isions I \'nlumc II I 78 
Code Amendments 
18.610.035 Additional Standards 
Applications must conform to all applicable standards in the following chapters: 
A. through H. 
[No change.] 
I. Tfee Rem oval Urban Forestry Plan (see Chapter 18. 790). 
J. through L. 
[No change.] 
18.610.040 through 18.610.060 
[No change.] 
l.ity of Tigard Urban Forestry Code ReYisions I Volume 11 I 79 
75 
Commentary 
18.620 TIGARD TRIANGLE D ESIGN STANDARDS 
The Tigard Triangle has design standards that are in addition to the base standards in o ther 
chapters in the code. Among these are landscaping standards that specify additional size, species 
and location standards fo r the Tigard T riangle. Some of these standards are unclear, incomplete 
or inconsistent and the purpose o f the revisions to this chapter is to clarify, correct and ensure 
consistency among the provisions. 
7(, 
City of Tigard Urban Forestry Code Re,-isions I Volume II I 80 
CHAPTER 18.620 
Sections: 
18.620.010 
18.620.020 
18.620.030 
18.620.040 
18.620.050 
18.620.060 
18.620.070 
18.620.080 
18.620.090 
TIGARD TRIANGLE DESIGN STANDARDS 
Purpose and Applicability 
Street Connectivity 
Site Design Standards 
Building Design Standards 
Signs 
Entry Portals 
Landscaping and Screening 
Street and Accessway Standards 
Design Evaluation 
18.620.010 and 18.620.020 
[No change.] 
18.620.030 Site Design Standards 
Code Amendments 
A. Compliance. All development must meet the following site design standards. If a parcel is 
one acre or larger a phased development plan must be approved demonstrating how these 
standards for the overall parcel can be met. Variance to these standards may be granted if 
the criteria found in Section 18.3 70.01 O.C.2, governing criteria for granting a variance, is 
satisfied. 
1. through 5. 
[No change.] 
77 
City of Tigard Urban Forestry Code Rc,·isions I Volume II I 81 
Commentary 
18.620.030 Site D esign Standards 
The L-1 and L-2 standards in the design districts have been problematic because they are 
unclear. T he am endments are intended to clarify the standards, provide additional space for tree 
growth, while retaining the original intent o f the standards. 
T he landscape setback for parking lots from streets has been increased from 5 to 8 feet to allow 
parking lo t trees to be planted in the setback (consistent with the requirements in Chapter 
18.745 and Section 13 of the Urban Forestry Manual) and have additional soil volume in the 
design district. The Urban Forestry Manual consists o f administrative rules to implement the 
details o f the urban fores try related code provisions in Title 8, Title 18 and other applicable titles 
in the Tigard Municipal Code. 
78 
City of Tigard Urban l'orcstry Code Rc,·isions I \ 'olumc II I 82 
Code Amendments 
6. Parking location and landscape design - Parking for buildings or phases adjacent to 
public street rights-of-way must be located to the side or rear of newly constructed 
buildings. If located on the side, parking is limited to 50% of the street frontage and 
must be behind a landscaped area constructed to an L-1 Landscape Standard. The 
minimum depth of the L-1 landscaped area is !We ~feet or is equal to the building 
setback, whichever is greater. Interior side and rear yards shall be landscaped to aJl L-2 
Landscape Standard, except where a side yard abuts a public street where it shall be 
landscaped to an L-1 Landscape Standard. See Diagram 2. 
~ ~E-
0'-/0" s.~l '~ Prover_!r~ 
sM;;;ik 
Street 
~ ~v ~~· 
. ~ \,. 
, 
' · N\ 11~1.1 I <Q 
~ 
.... 
tJ -¥Min. ~tbaclt 0'-10' S.tbad 
Tigard Triangle Street Plan - Diagram 2 
18.620.040 Building Design Standards 
lN o change] 
79 
City of Tigard Urban Forestry Code Revisions I Volume 11 I 83 
Commentary 
18.620.050 Signs 
No change to Section 18.620.050. 
18.620.060 E ntry Portals 
In the Landscape and Street Standards (a t the end o f the existing chapter), it specified that columnar 
trees were reguired near entry portals. The amendment reiterates this reguirement in the entry 
portal design reguirement. 
18.620.070 Landscaping and Screening 
The design districts have reguirements that supersede the reguirements in Chapter 18.745. T hese 
include the L-1 and L-2 reguirements. 
T he L-1 reguirement is essentially an enhanced screen o f the parking lo t from the street. Larger 
than average trees are reguired to provide an immediate screen effec t. T he language has been 
modified to make the purpose o f the reguirements more clear. The term "major or minor arterial" 
has been changed to "public street" because the o ther design districts reguire an L-1 screen from 
public streets, so for consistency L-1 screens should be reguired in the Tigard Triangle. 
80 
City or T igard Urban Forestry Code Rc,· isions I \'olumc II I 84 
Code Amendments 
18.620.050 Signs 
[No change.] 
18.620.060 Entry Portals 
A. Required locations. E ntry portals shall be required at the primary access points into the 
Tigard T riangle. 
1. Location - E n try portals shall be located at the intersections o f 99W and D artmouth; 
99W and 72nd; I-5 and D artmouth; Hwy. 217 and 72nd; and at the Hwy. 217 
Overcrossing and D artmouth. 
2. D esign - The overall design of entry portals shall relate in scale and detail to both the 
automobile and the pedestrian. A triangle m otif and at least 2 trees according to the L-2 
standard shall be incorporated into the design o f entry portals. 
18.620.070 Landscaping and Screening 
A. Applicable levels. Two levels of landscaping and screening standards are applicable to the 
Tigard Triangle. T he locations where the landscaping or screening is required and the depth 
of the landscaping or screening are defined in o ther sub-sections of this section. These 
standards are minimum requirements. H igher standards may be substituted as long as all 
height limitations are met. 
1. L-1 bew Parking Lot Screen For general landscaping of landscaped and screened areas 
·v.'ithin parking lo ts and along local coHectors and local streets, plantillg standards of 
Chapter 18.7 45 Landscaping and Screening, shaH appl-y. The L-1 standard applies to 
setbacks on public streets major and n-Mnor arterials. Where T he L-1 standard is in 
addition to o ther standards in other chapters o f this title. T he setback is shall be a 
minimum of 5 R._feet between the parking lo t and ft public street. major or minor 
arterial, L-1 trees shall be considered parking lo t trees and spaced between 30 and 40 
feet on center within the setback. All L-1 trees shall be a minimum of planted at 3 1/2 
inch caliper at the time o f planting. at a maximum of 28 feet on center. Shrubs shall be 
of a variety that will provided-a 3 foot high screen and a 90% opacity within one year. 
Groundcover plan ts mus t fully cover the remainder of landscape area within two 
years. Anv tree planted in: excess of a 2 inch caliper shaH be eli~ible for fuR miti~ation 
eretfu.: 
81 
City of Tigard Urban Fores try Code Re,·isions I Volume II I 85 
Commentary 
18.620.070 Landscaping and Screening 
The L-2 requirement is for all o ther required landscaping and requires larger than average trees to 
provide an immediate effect. T he L-2 requirement is also intended to create cohesive tree designs 
for various locations in the district. In the landscape and street standards (at the end o f the existing 
chapter), the various tree types and loca tions are specified. W hile the design elements have been 
retained, terminology has been revised to be consistent with the terminology used in the Urban 
Fores try Manual (small, medium, large, columnar trees), and the table has been moved closer to the 
L-2 code language to make cross referencing easier. The language has also been modified to make 
the purpose o f the requirements more clear. 
Table 18.620.1 L-2 Tree Standard s 
The design elements o f the landscape and street standards table (a t the end of the existing chapter) 
have been retained. T he terminology has been revised to be consistent with the terminology used in 
the Urban Fores try ·Manual (small, medium, large, columnar trees), and the table has been moved 
closer to the L-2 code language to make cross referencing easier. 
82 
City of Tigard Urban I ;orcstry Code RcYisions I \' olumc II I 86 
Code Amendments 
2. L-2 General Landscaping - Fol' gen:el'ftl lftfidseftping of lftndseftped ftftd sel'eened fttTftS 
within pftdcing lots, loeft! eolleetms ftnd loeftl stl'eets, plafittng stftnduds of Chftptel' 
18.745, Lftndseftping ftnd Se£eening, slull ftpply. The L-2 standard applies to all other 
trees and shmbs required by this chapter and Chapter 18.745 (except those required for 
L-1 Parking Lot Screen). For trees and shmbs required by Chapter 18.745 the L-2 
standard is an additional standard. L-2 trees that are also street trees median trees and 
trees required to frame entry portals shall be selected in conformance with Table 
18.620.1 below. If conformance with Table 18.620.1 is precluded by physical 
constraints caused by public utilities or required public improvements the Director may 
approve alternative selections. All L-2 trees shall be pl'Ovided ftt a minimum .o.L2-Vz 
inch caliper at the time of planting., ftt ft m:ftxim:um: spfteing of 28 feet. Shmbs shall be 
of a size and quality to achieve the required landscaping or screening effect within two 
years. Anv tl'ee nlftfited in C{eess of ft 2 inch eftHDel' shftll be eli~ble fm full m:itt~fttton 
ffCdi.t.: 
IABLE 18.620.1 
L-2 TREE STANDARDS 
G eneral I ree Location Spedfic Iree I ype2 
~l 
Street Tree l2nd AYenue T . ::~ro-P Shh1tP Sh·ppt T r PP <: 
Street I ree DartmQ:uth Street Laro-F Stahltf' Street T tPP <: 
Street Iree GEm AYenue CQlumnar Irees 
Street Iree Atlanta Street CQlumnar Irees 
Street I ree H ::~mntnn StrFFt CQlumnar I rees 
Street Tree .6..6th AYenue T .::~ ro-P Shh1tP St!"Pf't T r PP <: 
Street Iree Backage RQad EYen Mix Qf Large Medium and Small 
Stature Street I rees 
Street Iree All Qthel· lQcal streets M edium Stature Street I rees 
Median Tree l2nd AYenue T . ::~ro-P Shh1tP ~Ft T r PP <: 
Median I ree GEm AYenue Laro-F StahuF Street T t·FP <: 
Median I ree Atlanta Street Larp-e --s;; ture ~et TreF<: 
Median Iree H a -~~~ Street T . ::~to-P StahJtf' SttPPt T r PP <: 
Pmtal I ree All reguired pmtals CQlumnar I rees 
18.620.080 Street and Accessway Standards 
[Renumber Table 18.620.1 to Table 18.620.2] 
18.620.090 Design Evaluation 
[No change.] 
0 18 745 18 790 the I. 2 Tree Standard s apply 
1 When these tree types are reqmrC1} ! s acin are in the U rban Forestry Mauna · d 1 , Chapter 18 62 o r 1 2 Additional specifications for spectes p lantmg and p g 
83 
City of Tigard Urban Forestry Code Rc,·isions I Volume II I 87 
Commentary 
Landscape and Street Standards 
The design elements o f the Landscape and Street Standards table have been retained and 
converted to table 18.620.1. T he terminology has been revised to be consistent with the 
terminology used in the Urban Forestry Manual (small, m edium, large, columnar trees), and the 
table has been moved closer to the L-2 code language to make cross referencing easier. 
84 
City of TiganJ Urban l'orcstry Code Rc,-isions I \'olumc II I HS 
Code Am endments 
Landscape and Street Standards 
!J> 
Landscape Standards: 
Street Name 
72',., Avenue 
Loca I Streets 
Ponals 
Parking lots 
Broad-spre>ding 
Broad-sDrc;•din•• 
Bnl.itd-!'DrCildin•~ 
Bro.•d·sorcadin 
Broad-sprc;1ding 
Bro:od·sprcading 
Street Trees 
27 fcc1 o.c. 
27 feet o c. 
27 feet o c. 
22 feet o.c. 
22 feet o.c. 
22 feet o.c. 
22 feel o.c. 
22 feet o.c. 
12 feet o.c. 
27 feet o.c. 
21 feet o.c. 
l..ocatiGn 
Between sidewalk and street 
Center nu .. -diom 
Between !liidcwalk .1nd street 
Between sidewalk and street 
Center median 
1 All curb-side planting strips and mcdiaru sha be plant with t.1wn of groundcover. Pla nter strips 
between the sidewalk and street along 72''" Aven sh be lawn except where paved areas •~tend to the 
curblinc and tree grates arc provided around trees. i:dians on 68th Avenue, Atlanta and Hampton shall 
have consistent lawn or groundcovcr plantings for tire length of the street with accents at 
intersections. 
1 rr~! : $ li. 
;~\ 
z ~ II 
~I -~ . i 
""?· 
Columnar Street Tree 
Tigard Triangle Street Plan 
Details 
City of 'l'igard Urban l'orcstry Code Revisions I Volume II I 89 
-
Street Tree 
85 
Commentary 
Tigard Triangle Street Plan 
The parking lo t setback requirement has been revised to show an 8 foot rather than a 5 foot 
se tback per the revised L-1 standard. 
86 
City of Tiganl Urban l'orest:ry Code Rc,·isions I Volume II I 90 
Landscape and Street Standards 
1 
~ 
Curb extension and concrete intersection at 
at intersections on Major and Minor Arterials. 
~ 
.!:! 
L:JS11t • 
plan 
~ 
;..., 
~ 
Typical landscape and parking at minimum setback. 
Tigard Triangle Street Plan 
Details 
City o f Tigard Urban Forestry Code Re,·isions I Volume II I 91 
Code Amendments 
87 
Commentary 
18.630 WASHINGTO N SQ UARE REGIONAL CENTER D ESIGN STANDARDS 
The Washington Square Regional Center has design standards that are in addition to the base 
standards in o ther chapters in the code. Among these are landscaping standards that specify 
additional size, species and location standards for the Washington Square Regional Center. 
Some o f these standards are unclear, incomplete or inconsistent and the purpose o f the revisions 
to this chapter is to clarify, correct and ensure consistency among the provisions. 
88 
City of Tiganl Urban l'orestry C:ocle Re,·isions I \'olume II I 92 
Code Amendments 
Chapter 18.630 
WASHINGTON SQUARE REGIONAL CENTER DESIGN STANDARDS 
Sections: 
18.630.010 
18.630.020 
18.630.030 
18.630.040 
18.630.050 
18.630.060 
18.630.070 
18.630.080 
18.630.090 
18.630.100 
18.630.110 
Purpose and Applicability 
Development Standards 
Pre-existing Uses 
Street Connectivity 
Site Design Standards 
Building Design Standards 
Signs 
Entry Portals 
Landscaping and Screening 
Street and Accessway Standards 
Design Evaluation 
18.630.010 through 18.830.040 
[No change.] 
City of Tigard Urban l'orestry Code Revisions I Volume II I 93 
89 
Commentary 
18.630.050 Site D esign Standards 
T he L-1 and L-2 standards in the design districts have been problematic because they are 
unclear. The amendments are intended to clarify the standards, provide additional space for tree 
growth, while retaining the original intent of the standards. 
T he landscape setback for parking lo ts from streets has been increased from 5 to 8 fee t to allow 
parking lo t trees to be planted in the setback (consistent with the requirements in Chapter 
18.745 and Section 13 of d1e Urban Fores try Manual) and have additional soil volume in the 
design district. The Urban Forestry l'vianual consists of administrative rules to implement the 
details o f the urban fores try rela ted code provisions in Tide 8, Tide 18 and o ther applicable tides 
in the Tigard Municipal Code. 
90 
City of Ti;.,'<lrd Urban Fo rc>Lry Code Rc,·i>ion> I \'olumc II I 94 
Code Amendments 
18.630.050 Site Design Standards 
A. Compliance. All development must m eet the following site design standards. If a parcel is 
one acre or larger a phased development plan may be approved demonstrating how these 
standards for the overall parcel can be met. Variance to these standards may be granted if 
the criteria found in Section 18.3 70.01 O.C.2, governing criteria for granting a variance, is 
satisfied. 
1. through 4. 
[No change.] 
5. Parking location and landscape design. 
a. Purpose. T he emphasis on pedestrian access and a high quality streetscape 
experience requires that priva te parking lo ts that abut public streets should not be 
the predominant street feature. Where parking does abut public streets, high quality 
landscaping should screen parking from adjacent pedestrian areas. 
b. Standard. Parking for buildings or phases adjacent to public street rights-of-way 
must be located to the side or rear o f newly constructed buildings. When buildings 
or phases are adjacent to more than one public street, prima1y street(s) shall be 
identified by the City where this requirement applies . In general, streets with higher 
functional classification will be identified as primaty streets unless specific design or 
access factors favor another street. If located on the side, parking is limited to 50% 
o f the primary street frontage and must be behind a landscaped area constructed to 
an L-1 landscape standard. T he minimum depth o f the L-1 landscaped area is .five 
~feet or is equal to the building setback, whichever is greater. Interior side and 
rear yards shall be landscaped to ag L-2 landscape standard, except where a side yard 
abuts a public street, where it shall be landscaped to an L-1 landscape standard. 
91 
City of Tigard Urban Forestry Code Rc,·isions I Volume II I 95 
Commentary 
18.630.090 Landscaping and Screening 
The design districts have requirements that supersede the requirements in Chapter 18.745. 
These include the L-1 and L-2 requirements. 
The L-1 requirement is essentially an enhanced screen o f the parking lot from the street. Larger 
than average trees are required to provide an immediate screen effect. T he language has been 
modified to make the purpose o f the requirements more clear. 
T he L-2 requirement essentially requires that any trees required to be planted in Washington 
Square Regional Center be 2 1/2 caliper at planting to provide a more immediate effect. The 
language has been clarified to reflect this. 
n 
City of Tigard Urban l;orcstry Code Rc,· isions I Volume II I 96 
Code Amendments 
18.630.060 through 18.630.080 
[No cha~ge.] 
18.630.090 Landscaping and Screening 
A. Applicable levels. Two levels of landscaping and screening standards are applicable. The 
locations were the landscaping or screening is required and the depth of the landscaping or 
screening are defmed in other sub-sections of this section. These standards are minimum 
requirements. Higher standards may be substituted as long as all height limitations are met. 
1. L-1 b6w Parking Lot Screen. For generallandscapin:g of landscaped and sereened areas 
within parking lots an:d alon:g local collectors and local streets, plan:tin:g stan:dards of 
Chapter 18.745 Lan:dscaping an:d Screening, shall apply. In: addition the Ihe_L-1 
standard applies to setbacks on public streets. major an:d minor arterials, and .,.here 
parkin:g lots abut public streets. The L-1 standard is in addition to other standards in 
other chapters of this title. Where the Ihe_setback ffl shall be a minimum of~ .8_feet 
between the parking lot and a public street,., L-1 trees shall be considered parking lot 
trees and spaced between 30 and 40 feet on center within the setback. All L-1 trees shall 
be planted at a minimum of 31/2 inch caliper at the time of planting. , at a maximum of 28 
feet on: center. Shrubs shall be of a variety that will provide a 3 foot high screen and a 
90% opacity within one year. Groundcover plants must fully cover the remainder of 
landscape area within two years. 
2. L-2 General Landscaping. For general landscapityg of lan:dscaped an:d sereened areas 
within: parking lots, and alon:g local collectors and local streets, plantin:g stan:dards of 
Chapter 18.745, Lan:dscaping and Screming, shall apply. The L-2 standard applies to all 
other trees and shrubs required by this chapter and Chapter 18.7 45 (except those 
required for the L-1 Parking Lot Screen,). For trees and shrubs required by Chapter 
18.7 45. the L 2 standard is an additional standard. In addition:, trees shall be provided at 
a rn:intn1:t1m All L-2 trees shall be 2V2 inch caliper at the time of planting., at a mHi:m:um 
spacit1:g of 28 feet. Shrubs shall be of a size and quality to achieve the required 
landscaping or screening effect within two years. 
18.630.100 and 18.630.110 
[No change.] 
93 
City of Tigard Urban Forestry Code Revisions I Volume IJ I 97 
Commentary 
18.640 DURHAM QUARRY DESIGN STANDARDS 
The Durham Quarry D esign Standards generally apply to the area known as Bridgeport Village. 
The proposed amendments to the Durham Quarry D esign Standards Chapter include: 
Sections 18.640.700 and 800 have been retitled consistent with the updated applicable code 
sections for sensitive lands and urban forestry plan. 
94 
City of Tigard Urban l'orc,try Code Rc,·isions I \'olumc II I 98 
Sections: 
18.640.010 
18.640.020 
18.640.030 
18.640.040 
18.640.050 
18.640.060 
18.640.070 
18.640.080 
18.640.090 
18.640.100 
18.640.200 
18.640.300 
18.640.400 
18.640.500 
18.640.600 
18.649.7{){) 
18.640.800 
Chapter 18.640 
DURHAM QUARRY DESIGN STANDARDS 
Purpose 
Permitted Uses 
Conditional Uses 
Applicability 
Development Standards 
Determining Net Acres 
Signs 
Reserved 
Reserved 
Access 
Design Standards 
Design Compatibility Standards 
Landscaping and Screening 
Off-Street Parking and Loading 
Environmental Standards 
Floodplain District Sensitive Lands 
Wetlands Protection District Urban Forestry Plan 
18.640.010 through 18.640.100 
[No change.] 
City of Tigard Urban Forestry Code Revisions I Volume II I 99 
Code Amendments 
95 
Commentary 
18.640.200 Site D esign Standards 
T he landscape setback for parking lo ts from streets has been increased from 5 to 8 feet to allow 
parking lo t trees to be planted in the setback (consistent with the requirements in Chapter 
18.745 and Section 13 o f the Urban Forestry Manual) and have additional soil volume in the 
design district. T he Urban Forestry Manual consists o f administrative rules to implement the 
details o f the urban forestly related code provisions in Title 8, Title 18 and other applicable titles 
in the Tigard Municipal Code. 
<)(, 
City of T igard Urban Forc,try Code RcY i>io ns I \' o lum c II I 11)(1 
Code Amendments 
18.640.200 Design Standards 
A. [No change.] 
B. Site design standards. Development shall meet the following site design standards. 
1. through 4. 
[No change.] 
5. Parking location and landscape design. Parking for buildings or phases adjacent to public 
street rights-of-way shall be located to the side or rear of newly constructed buildings. 
When buildings or phases are adjacent to more than one public street, primary street(s) 
shall be identified where this requirement applies. If located on the side, parking is 
limited to SO% of the street frontage and must be behind a landscaped area constructed 
to an L-1 Landscape Standard. The minimum depth of the L-1 landscaped area is !We 
~feet or is equal to the building setback, whichever is greater. Interior side and rear 
yards shall be landscaped to an L-2 Landscape Standard, except where a side yard abuts a 
public street, where it shall be landscaped to an L-1 Landscape Standard. See Section 
18.640.200.D. 
97 
City of Tigard Urban Forestry Code ReYisions I Volume II I 101 
Commentary 
18.640.200 Site D esign Standards 
The L-1 and L-2 standards in the design districts have been problematic because they are 
unclear. 
The L-1 requirement is essentially an enhanced screen of the parking lot from the street. Larger 
than average trees are required to provide an immediate screen effect. The language has been 
modified to make the purpose of the requirements more clear. 
The L-2 requirement essentially requires that any trees required to be planted in Bridgeport 
Village be 2 1/ 2 caliper at planting to provide a more immediate effect. The language has been 
clarified to reflect this. 
N o changes to Sections 18.640.300 through 18.640.600. 
18.640.700 Sensitive Lands, see Chapter 18.77 5 
The revision reflects the existing chapter title to correct a scrivener's error. 
18.640.800 Urban Fores try Plan, see Chapter 18.790 
The revision reflects the revised chapter title. 
98 
Cit;· of Tigard Urban l;orcstry Code RcYisions I Volume II I 102 
Code Amendments 
C. [No change.] 
D. Landscaping and screening. 
1. Applicable levels. Two levels of landscaping and screening standards are applicable. The 
locations where the landscaping or screening is required and the depth of the 
landscaping or screening are defmed in Section 18.640.400. These standards are 
minimum requirements. Higher standards may be substituted as long as all height 
limitations are met. 
a. L-1 l6w parking lot screen. Fof genefallandscapit1g of landscaped and sneened afeas 
with-in parking lots and along local collectms and local streets, plantffig standafds in 
Chaptef 18.745, Landscapmg and Screening, shall apply. In addition the Ihe_L-1 
standard applies to setbacks on public streets. major and minor arterials. The L-1 
standard is in addition to other standards in other chapters of this title. Where the 
Illi:_setback is- shall be a minimum of .£We ~feet between the parking lot and a 
public street. n1ajof or minor arterial, -t:rees- L-1 trees shall be considered parking lot 
trees and spaced between 30 and 40 feet on center within the setback. All L-1 trees 
shall be planted at a minimum of 3 V2 inch caliper at the time of planting. ,.-il"Ht 
maxit'ftum of 28 feet on center. Shrubs shall be of a variety that will provide a three-
foot high screen and a 90% opacity within one year. Groundcover plants must fully 
cover the remainder of landscape area within two years. 
b. L-2 general landscaping. For general landscapmg of landscaped and screened areas 
\-Vtthin: parking lots, and along local collectors and local streets , plantit'lg standards in 
Chapter 18.745, Landscaping and Screenffig, shall apply. The L-2 standard applies to 
all other trees and shrubs required by this chapter and Chapter 18.7 45 (except those 
required for the L-1 parking lo t screen). For trees and shrubs required by Chapter 
18.745. the L 2 standard is an additional standard. In addition, All L-2 trees shall 
be provided at a minimum 2 V2 inch caliper at the time of planting. , at a maxit'ftum 
spacing of 28 feet. Shrubs shall be of a size and quality to achieve the required 
landscaping or screening effect within two years . 
18.640.300 through 18.640.600 
[No change.] 
18.640.700 Sensitive L ands. see Chapter 18.775 Floodnlain District. see Chanter 18.775 
18.640.800 Urban Forestry Plan. see Chapter 18.790 Wetlands Protection District, see 
Chapter 18.775 
99 
City o f 'T'i ~-,rard Urban Forestry Code Rc,·isions I Volume II I 103 
Commentary 
18.715 DENSITY COMPUTIONS 
Section 18.790.050.D.1 allows a reduction in minimum density for the preserva tion o f a 
significant tree grove. T his allowed reduction in minimum density is re flec ted in this chapter. 
T he term "gross acres" (and the corresponding explanation o f what gross acres are) has been 
simplified with the term " to tal site acres". 
l llll 
City of Tigard Urban Fores try Code Rc,·isions I \' olumc II I 104 
Sections: 
18.715.010 
18.715.020 
18.715 .030 
18.715.010 
Purpose 
Chapter 18.715 
D ENSITY COMPUTATIONS 
Density Calculation 
Residential D ensity Transfer 
Purpose 
Code Amendments 
A. Purpose. The purpose of this chapter is to implement the comprehensive plan by 
establishing the criteria for determining the number of dwelling units permitted. 
18.715.020 D ensity Calculation 
A. D efinition of net development area. N et development area, in acres, shall be determined by 
subtracting the following land area(s) from the total site~ acres, which is all of the land 
included in: the legal description of the property to be developed: 
1. All sensitive land areas: 
a. Land within the 1 00-year floodplain, 
b . Land or slopes exceeding 25%, 
c. Drainage ways, and 
d. Wetlands, 
e. Optional: Significant tree groves or habitat areas, as designated on the City of Tigard 
Significant Tree Grove Map" or "Significant H abitat Areas Map"; 
2. through 5. 
[No change.] 
B. and C. 
[No change.] 
18.715.030 
[No change.] 
101 
City of Tigard Urban Forestry Code ReYisions I Volume II I 105 
Commentary 
18.745.010 Purpose 
i\ scrivener's error has been corrected because the chapter is intended to enhance the 
aes thetic and environmental quality of the city. 
Protection of existing street trees during new development is addressed through Chapter 18.790 
and Section 10 o f the Urban Forestry Manual. T he Urban Forestry Manual consists of 
admin.istrative rules to in1plement the details of the urban forestry related code provisions in 
Title 8, T itle 18 and o th er applicable titles in the T igard Mun.icipal Code. 
18.745.020 Applicability 
T he existing applicability section is too broad because it says it applies to all development. 
The proposed applicability conforms to current prac tice by applying the standards to Type I 
Conditional Use and Site D evelopment Review Minor Mod.ifications, and Type II and III land 
use reviews. The new soil volume requirements would apply to a more limited list of Type II 
and III land use reviews outlined in Section 18.7 45.040.£\.4 for street trees and Section 
18.745.050.E for parking lo t trees. 
The section explicitly requires trees in 18.7 45 to be included and subject to all of the 
requirements of a concurrent urban forestry plan (per 18. 790). 
1112 
City of Tigard Urban l'oresLry Code Re,·isions I \ 'olumc II I 10(, 
Sections: 
18.745.010 
18.745.020 
18.745.030 
18.745.040 
18.745.050 
18.745.060 
18.745.010 
Chapter 18.745 
LANDSCAPING AND SCREENING 
Purpose 
Applicability 
General Provisions 
Street Trees 
Buffering and Screening 
Re-vegetation 
Purpose 
Code Amendments 
A. Purpose. The purpose of this chapter is to es tablish standards for landscaping, buffering, and 
screening of land use within Tigard in order to enhance the aes thetic .and_environmental 
quality of the City: 
1. By protecting existin:g street trees and requumg the planting of street trees m new 
development~; 
2. through 4. 
[No change.] 
18.745.020 Applicability 
A. Applicability. The provisions of tllis chapter shall apply to all development that requires a 
Type I Conditional Use Minor Modification a Type I Site D evelopment Review Minor 
Modification any Type II land use review or any Type III land use review including the 
construction of new structw:es, renwdehng of existing structures where the landscaping is 
nonconforming (Section 18.760.0 40.C), and to a change of use y,1hich results in the need for 
increased on site parking or loading requirements or wh-ich changes the access requirements 
unless otherwise specified in any of the sections below. 
B. When urban forestry plan requirements concurrently apply. When the provisions of Chapter 
18.790 Urban Forestry Plan concurrently apply any trees required by this chapter shall be 
included in the urban forestry plan and subject to all of the requirements in Chapter 
18.790. When site development re * ie cv does not apply. Where the provisions of Chapter 
18.360, Site Development Review, do not apply, the Director shall approve, approve with 
conditions, or deny a plan subm-itted under the provisions of this chapter by n1:eans of a 
Type I procedure, as governed by Section 18.390.030, using the applicable standards in this 
chapter. 
103 
City of T·igard Urban Forestry Code RcYisions I Volume II I 107 
Commentary 
18.745.030 General Provisions 
T he general provisions are modified to clarify that applicable industry standards (including tree 
care industry standards) shall be used to determine what constitutes acceptable maintenance. 
Throughout the chapter, the term " landscaping and screening" is used to refer to items required 
by Chapter 18.745, and the term " plants" is used to refer to trees, shrubs and groundcover. 
104 
Cit~· of'J'igard Urban l'orc,;try Code Re,·i,; ion,; I \'olume I I I 108 
Code Amendments 
C. Site plan reguirements. The applicant shall submit a site plan. The Director shall provide the 
applicant with detailed information about this submission requirement. 
18.745.030 General Provisions 
A. Obligation to maintain Maintenance Responsibility. Unless otherwise provided by the lease 
agreement, the owner, tenant and his agent, if any, shall be jointly and severally responsible 
for the ongoing maintenance of all landscaping and screening used to meet the requirements 
of this chapter according to applicable industry standards. ~hich shaH be maintained in good 
condition so as to pfesent a healthy, neat and Ofdefly appeafance, shaH be feplaced Of 
fepaifed as necessafy, and shaH be lrept ffee fwm fefuse and debris . 
f d elopments shaH be contwHed . . . d " H plant gw wth in: landscaped afeas oe v B. Pfut1±fig feqtl:l:t'e · 2 1 . . 
by pmning, tfimm:i:ng Of ~the~v.'fse ~o t tha~ce Of fepaif of any public utility; 1 It ··111 not inteffCfe with t1e mam ena • \1V 
2. It will not festfict pedestfian of <Thiculaf access; and 
3. It will not constitute a tfaffic hazafd became of feduced visibility. 
Gll.Installation reguirements. The installation of all landscaping and screening required by this 
chapter shall be as follows: 
1. All landscaping and screening shall be installed according to applicable industry 
standards accepted plantin~ pwcedmes; 
2. The plant matefials All plants shall be of high grade, and shall meet the size and 
grading standards of the American Standards for NmbCfg Nurserv Stock (ANSI Z60, 1-
.f-9.8.62004, and any future revisions); and 
3. All b-landscaping and screening shall be installed in accordance with the provisions of 
this title. 
-9.C. Certificate of occupancy. Certificates of occupancy shall not be issued unless 
the landscaping requirements of this chapter have been met or other arrangements have 
been made and approved by the City such as the posting of a bond. 
ED_. Protection of existing plants vegetation. Existing vegetation ~-on a site shall be 
protected as follows nmch as eossible: 
1. The developer shall provide methods for the protection of existing <Tgetation plants to 
remain during the construction process; Mtd 
2. The plants to remain be saved shall be noted on the landscape plans (~i.e.,_, ftreftS 
plants not to be dismfbed to remain can be shown as protected with fencing): 
and fenced. ag in gnow fencin~ which can be elaced awund individual ti-eegi. 
105 
City of Tigard Urban Forestry Code Re,·isions I Volume II I 109 
Commentary 
18.745.030 General Provisions 
While snow fencing, etc. may be used to preserve existing shrubs and groundcover, an explicit 
cross reference is made to the tree preserva tion requirements in Chapter 18.790. 
A link is drawn between the regulations in Chapter 18.745, and other applicable rules in other 
chapters of the code. T his includes regulations related to hazard trees, street trees, urban 
forestry plan requirements, etc. 
18.745.040 Street Trees 
In accordance with existing practice, street trees are required as part of the approval process for 
Conditional Use (Type III), Downtown D esign Review (Typ e II and III), Minor Land Partition 
(Type II), Planned D evelopment (Type III), Site D evelopment Review (Type II) and Subdivision 
(Type II and III) permits. 
T he minimum number of street trees required is based on the project's street frontage and must 
conform to the planting requirements in Section 2 of the Urban Forestry Manual and the soil 
volume requirements in Section 12 of the Urban Forestry Manual. 
T he soil volume requirements outlined in Section 12 of the Urban Fores try Manual are based on 
the width of the non-street portion of the right of way. Soil volume requirements can be met 
through the use o f engineered soil under pavement (covered soil volume) if designed, inspected 
and documented by a landscape architect. Otherwise, soil volume requirements can be met by 
planting trees in landscape areas with sufficient soil. 
lOG 
City o f TigarJ Urban Forestry CoJc Rc,·isions I Volume II I 11 0 
Code Amendments 
3. The tree protection provisions outlined in Chapter 18.790 and the Urban Forestry Manual 
shall apply to the land use review types identified in Section 18.790.020.A. 
E . Ongoing tree related rules and regulations. Any trees used to meet the requirements of this 
chapter shall be subject to all applicable tree related rules and regulations in other chapters 
and titles of the Tigard Municipal Code and Tigard Development Code. 
F. Care of landscaping along public rights of way. Appropriate methods for the care and 
maintenance of street trees and landscaping materials shall be pro ,·ided by the o M1er of the 
propC¥ty abutting the rights of v.,ay unless otheru,ise requi:fed for emergency conditions and 
the safety of the general public. 
G. Conditions of approval of existing vegetation. The review procedures and standards for 
required landscaping and screening shall be specified in the conditions of approval dming 
development review and in no instance shall be less than that required for conventional 
development. 
H. Height restrictions abutting public rights of "vvay. No trees, shmbs or plantings more than 18 
inches in height shall be planted in the public right of way abutting roadways ha·ving no 
established cmb and gutter. 
18.745.040 Street Trees 
A. Street Tree Standards. 
1. Street trees shall be required as part of the approval process for Conditional Use (I.ype 
III) Downtown Design Review Q"'ype II and III) Minor Land Partition (Type II) 
Planned Development (Type III) Site Development Review Q'ype II) and Subdivision 
(Iy_pe II and III) permits. 
2... The minimum number of required street trees shall be determined by dividing the linear 
amount of street frontage within or adjacent to the site (,in feet) by 40 feet. When the 
result is a fraction the minimum number of required street trees shall be determined by 
rounding to the nearest whole number . 
.3.., Street trees required by this section shall be planted according to the standards in Section 
2 of the Urban Forestnr Manual. 
.4.,_ Street trees required by this section shall be provided adequate soil volumes according to 
the standards in Section 12 of the Urban Forestrv Manual. 
2 Street trees required by this section shall be planted within the right of way whenever 
practicable according to the standards in Section 2 of the Urban Forestty Manual. Street 
trees may be planted no more than 6 feet from the right of way according to the 
standards in Section 2 of the Urban Forestry Manual when planting within the right of 
way is not practicable. 
107 
City of Tigard Urban Fores try Code ReYisions I Volume IT I 111 
Commentary 
18.745.040 Street T rees 
Existing trees are allowed as street trees if they would be permitted as newly planted trees and 
they are adequately protected through the urban forestry plan requirements in Chapter 18.790. 
This would occur as a technical decision without requiring an adjustment permit in order to 
incentivize preserva cion o f existing trees. 
If the required number o f street trees cannot be provided, a fee in lieu of planting option is 
available to cover the city's cost o f planting. 
The existing provisions for street trees will be replaced with the new provisions which are 
primarily in Sections 2 (s treet tree planting standards) and 12 (s treet tree soil volume standards) 
o f the Urban Forestry Manual. 
108 
City of Tigard Urban l;orc>try Code ReYi>ion> I \'olumc II I 11 2 
<
 
0 c 3 " 
N
 
Commentary 
18.745.040 Street T rees 
Strikethroughs o f existing street tree provisions continued. The existing provisions for street 
trees will be replaced with the new provisions which are primarily in Sections 2 (s treet tree 
planting standard s) and 12 (s treet tree soil volume standards) of the Urban Forestry Manual. 
110 
City of Tigard Urban Forestry Coclc Rc,-isions I \'olumc II I 11 4 
c ...,
.,
 
<
 
c c 3 (") =
 
(")
 
0 0..
. 
(!)
 >
 8 g 0... 8 (!) ::l .... (/) 
Commentary 
18.745.050 Buffering and Screening 
Buffers are required between incompatible land uses . Trees are required in the buffer, and the 
language and spacing requirements for buffer trees has been revised to be consistent with the 
requirements in the Urban Fores try Manual. 
112 
City of T igard Urban Fo re> try Code Re,-i>ion> I \'olumc II I 116 
Code Amendments 
F. Replacemetlt of street trees. Existing street trees ren1oved by development projects or other 
construction sh:al:l be replaced by the developn "v:ith: those types of trees approved by the 
Director. The replacement trees shal:l be of a size and species sinlliar to the trees that are 
being removed unless lesser sized alternatives are approved by the Director. 
G. Granting of adjustments. Adjustments to the street tree requirements n1ay be gt·anted by the 
Director by means of a Type I procedure, as regulated in Section 18.390.030, using approval 
nitr1·i51 iA Srrtion 1 g 17() ()?() (' {i h 
H. Location of trees near signalized intersections. The Director may al:lo,.;r trees closer to 
specified intersections which: are signalized, provided the prmisions of Chapter 18.795, 
"'Visual Clearance, are satisfied. (Ord. 09 13) 
18.745.050 Buffering and Screening 
A. General provisions. 
[No change.] 
B. Buffering and screening requirements. 
1. through 3. 
[No change.] 
11 3 
City ofTigard Urban Forestry Code Rc,·isions I Volume II j 117 
Commentary 
18.745.050 Buffering and Screening 
Buffers are required between incompatible land uses. T rees are required in th e buffer, and the 
language and spacing requirements for buffer trees has been revised to be consistent with the 
requirements in the Urban Fores tt-y Manual. 
114 
City of Tigard Urban l:orcstry Code Rc,·isions I \' o lumc II I I I K 
Code Amendments 
4. T he rrurumum improvements within a buffer area shall consist o f combinations for 
landscaping and screening as specified in Table 18.745.1. In addition, improvements 
shall meet the following specifications: 
a. A t least one row o f trees shall be planted. They shall be chosen from any of the tree 
lists in the Urban Forestry Manual (except the Nuisance Tree Lis t) unless otherwise 
approved by the Du:ector and have a minimum caliper of twt7 1112 inches at fotlf feet 
in height above grade for deciduous trees and a mi.Jlimum height o f !We six feet ftigh 
for evergreen trees at the time of planting. Spacing for trees shall be as follows: 
(1) Small stature or narrow stature columnar trees, under 25 feet tall or less than16 
feet wide at maturity shall be spaced no less than 15 feet on center and 
llQ_further greater than ~ 2D....feet on center ftPffi· 
(2) Medium~ stature trees between 25 feet to 40 feet tall and . .,,r-ith:16 feet to 35 
feet •.,;ride branching at maturity shall be spaced no less than 20 feet on center and 
llQ_grea ter than 30 feet on center ftPffi· 
(3) Large stabue trees, o.·er 40 feet tall and with mme than 35 feet vAde branching at 
matut·ity, shall be spaced no less than 30 feet on center and no greater than W :ill 
feet on center ftPffi· 
b . In addition, at least 10 five-gallon shrubs or 20 one-gallon shrubs shall be planted for 
each 1,000 square feet of required buffer area. 
c. T he rem ainU1g area shall be planted ill lawn or o ther livillg ground cover. 
5. through 9. 
[No change.] 
C. and D. 
[No change.] 
11 5 
City ofTigard Urban Forestry Code Re,·isions I Volume II 1 119 
Commentary 
18.745.050 Buffering and Screening 
Special screening standards require trees in parking lots. Language has been added to specify 
that non-conforming screening in parking lo ts shall no t be allowed to become any less 
conforming (through a Type I land use permit for example) . Screening in parking lots will be 
required to be brought into conformance when issuing major development permits (Type II and 
III). 
The parking lo t screening requirements have been revised to require 30 percent actual canopy 
cover (directly above the parking area) rather than one tree for every seven parking spaces. 
Requiring canopy m ore directly relates to the city's urban fores try goals, whereas requiring a 
certain number o f trees per parking spaces can be met by deleting parking spaces (rather than 
planting trees). Section 13 of the Urban Forestry Manual is referenced for more detailed parking 
lo t tree, soil volume and canopy plan requirements. Parking lo t tree canopy plans are required to 
be designed, inspected and documented by a landscape architect unless an arborist can meet the 
requirements through a concurrent urban fores try plan per Chapter 18.790. Soil volume 
requirements can be m et through the use o f engineered soil under pavement (covered soil 
volume) if designed, inspected and documented by a landscape architect. Otherwise, soil 
volume requirements can be met by planting trees in landscape areas with sufficient soil. 
11 6 
City of Tigard Urban l'orcstry Code RcYisions I \'olumc II I 12U 
Code Amendments 
E. Screening: special provisions. 
1. Screening and landscaping of parking and loading areas: 
a. Screening of parking and loading areas is required. In no cases shall nonconforming 
screening of parking and loading areas (,i.e. nonconforming situation) be permitted to 
become any less conforming. Nonconforming screening of parking and loading 
areas shall be brought into conformance with the provisions of this chapter as part 
of the approval process for Condition Use (Type III) Downtown Design Review 
(Type II and III) Planned Development (Iype III) and Site Development Review 
(Type II) permits only. The specifications for this screening are as follows: 
(1) Landscaped parking areas shall include special design features which effectively 
screen the parking lot areas from view. These design features may include the use 
of landscaped berms, decorative walls and raised planters; 
(2) Landscape planters may be used to define or screen the appearance of off-street 
parking areas from the public right-of-way; 
(3) Materials to be installed should achieve a balance between low lying and vertical 
shrubbery and trees; 
. d to achieve ll b regmre . 
. aces and aisles sha /the parking area m . luding parkmg sp .· ' directly abov . . areas me at m tunt; (4) All parking anopy cover 30% tree c at least 
accordance with the Parkin Urban Forestrv Manual g. Lot Tree Canopy Standard . . 
r••kffig oreos '"d sh H ,b Trees sh•H be rhHtcd . l s m S«non 13 of the 
• 1. ' • e e~ H d' ID •llils d · 
"" '"'"" ""'''i"' . h"''"l' - tsffibutcd •rul ,core tslaHds ;, aH ~mace~ 1fl order to nmvide OH: tle basis of one tfee £; • 
a canonv effect; and ~1 
(5) The rntn:l:ffiun1 di:t11ension of the landscape islands shall be three feet and the 
landscaping shall be protected from vehictliar damage by some form of wheel 
guard or curb. 
2. through 4. 
[No change.] 
F. Buffer Matrix 
[No change.] 
117 
City of Tigard Urban Forestry Code Re,·isions I Volume II I 121 
Commentary 
18.745.060 Re-vegetation 
For consistency, the term " landscaping and screening" is used to refer to the requirements in 
Chapter 18.745. 
A cross reference has been added to require soil stockpiling consistent with an approved urban 
forestry plan per 18.790. When there is no urban forestry plan, soil stockpiling shall be outside 
the driplines of existing trees. 
TABLE 18.745.1 , BUFFER MATRIX 
Table 18.745.1 is unchanged. 
I 18 
Cit)' of T iga rd Urban l;orc>try Code Rc,·isions I \'olumc I I I I 22 
Code Amendments 
18.745.060 Re-vegetation 
A. When re-vegetation is required. Where natural vegetation has been removed through grading 
in areas not affected by the landscaping and screening requirements and that are not to be 
occupied by structures, such areas are to be replanted as set forth in this section to prevent 
erosion after construction activities are completed. 
B. Preparation for re-vegetation. Topsoil removed from the surface in preparation for grading 
and construction is to be stored on or near the sites and protected from erosion while 
grading operations are underway; and 
1. Such storage__iliall__may not be located consistent with an approved urban forestry plan 
per Chapter 18.790 or outside the tree canopy driplines where it would cause su ffoca tion 
of roo t systems of trees intended to be preserved in cases when there this is no approved 
urban forestry plan; and 
2. A fter completion of such grading, the topsoil is to be restored to exposed cut and fill 
embankments or building pads to provide a suitable base for seeding and planting. 
C. Methods of Re-vegetation 
[No change.] 
[No Changes to this Table] 
TABLE 18.745.1 
BUFFER MATRIX 
City of Tigard Urban Forestry Code ReYisions I Volume II I 123 
119 
Commentary 
Table 18.745.2, BUFFER COMBINATIONS FOR LANDSCAPING AND SCREENING [1] 
Specific buffers are required based on the level of incompatibility of adjacent land uses by Table 
18.745.1 (Buffer Matrix). The specifications for tree planting in Table 18.745.2 have been 
revised for compatibility with Section 18.745.050.B and the standards in the Urban Forestry 
Manual. 
Footnote 2 provides a cross reference to the more detailed spacing standards in Section 
18.7 45.050.B.4. 
Existing footnote 2 has been struck because there is no adjustment process for buffer trees 
(scrivener's error). 
1211 
Cit0· of T igard Urban Forestry Code RcY isions I \'olumc II I 124 
Code Amendments 
TABLE 18.745.2 
BUFFER COMBINATIONS FOR LANDSCAPING AND SCREENING [1] 
Options Width Trees[2] Shrubs or Screening 
(feet) (per linear feet of Groundcover 
buffer) 
A -- 10 -- Lawn/ --
living groundcover 
B -- 10 ~15' min/~ :ill' max Lawn/ --
spacmg living groundcover 
1 10 Shrubs 4' hedges 
c 2 8 15' min/ W' .:l:.(L max Shrubs 5' fence 
spacmg 
3 6 Shrubs 6' wall 
1 20 Shrubs 6'hedge 
D 2 15 W 15 'min/ W .:l:.(L Shrubs 6' fence 
max spacmg 
3 10 Shrubs 6' wall 
1 30 W15' min/W~ Shrubs 6' hedge or 
max spacmg fence 
E 
2 25 Shrubs 5' earthen berm 
or wall 
F -- 40 W15'min/W~ Shrubs 6' hedge, fence, 
max spacmg wall or berm 
[1] Buffers are not required between abutting uses that are of a different type when the uses are 
separated by a street as specified in Section 18.745.050.A.2. 
[2] Spacing of trees depends on stature: see Section 18.745.050.B.4. 
[2] Adjustments from these reqttll'ements can be obtain:ed; see Section 18.370.020.G. 4. 
121 
City of Tigard Urban Forestry Code Re,·isions I Volume II I 125 
I 
Commentary 
Table 18.745.2, BUFFER COMBINATIONS FOR LANDSCAPING AND SCREENING [2] 
Illustrations left unchanged. 
122 
City of Tigard Urban l 'or~stry Code RcYisions I \'olumc II I 126 
n
 
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Commentary 
18.775 Sensitive Lands 
Chapter 18.790 specifies that urban forestty plans are required for Type II and III Sensitive Lands 
Reviews. A fter reviewing existing project typ es and conditions, it was determined that Type II and 
III Sensitive Lands Reviews have consistent and tangible impacts on trees. 
Consistent with the approval criteria for other land use permits, reference to "compliance with all 
applicable requirements of this title" has been added to each of the approval criteria for each 
sensitive lands permit type. This cross reference provides a link back to chapter 18.790 to ensure 
the urban fores try plan standards are met for Type II and III Sensitive Lands Reviews. 
124 
City of Tigard Urban l;orcstry Code RcYisions I \'olumc II I 128 
Code Amendments 
Chapter 18.775 
SENSITIVE LANDS 
Sections: 
18.775.010 Purpose 
18.775.020 Applicability of Uses: Permitted, Prohibited, and Nonconforming 
18.775.030 Administrative Provisions 
18.775.040 General Provisions for Floodplain Areas 
18.775.050 General Provisions for Wetlands 
18.775.060 Expiration of Approval: Standards for Extension of Time 
18.775.070 Sensitive Land Permits 
18.775.080 Application Submission Requirements 
18.775.090 Special Provisions for Development within Locally Significant Wetlands 
and Along the Tualatin River, Fanno Creek, Ball Creek, and the South Fork of Ash 
Creek 
18.775.100 
18.775.110 
18.775.120 
18.775.130 
18.775.140 
Adjustments to Underlying Zone Standards 
Density Transfer 
Variances to Section 18.775.090 Standards 
Plan Amendment Option 
Significant Habitat Areas Map Verification Procedures 
18.775.010 through 18.775.060 
[No change.] 
City of Tigard Urban Forestry Code Rc,·isions I Volume II I 129 
125 
Commentary 
18.775.070 Sensitive Lands Permits 
Consistent with the approval criteria for other land use permits, reference to "compliance with all 
applicable requirements of this title" has been added to the approval criteria for sensitive lands · 
permits within tl1e 1 00-year floodplain. This cross reference provides a link back to chapter 18.790 
to ensure the urban foreSli)' plan standards are met for Type II and III Sensitive Lands Reviews 
within the 1 00-year floodplain. 
Consistent with the approval criteria for other land use permits, reference to "compliance with all 
applicable requirements of this title" has been added to the approval criteria for sensitive lands 
permits on steep slopes. This cross reference provides a link back to chapter 18.790 to ensure the 
urban forestry plan standards are met for Type II and III Sensitive Lands Reviews on steep slopes. 
Consistent with the approval criteria for other land use permits, reference to "compliance with all 
applicable requirements of this title" has been added to the approval criteria for sensitive lands 
permits within drainageways. This cross reference provides a link back to chapter 18.790 to ensure 
the urban foresu-y plan standards are met for Type II and III Sensitive Lands Reviews within 
drainageways. 
Consistent with the approval criteria for other land use permits, reference to "compliance with all 
applicable requirements of this title" has been added to d1e approval criteria for sensitive lands 
permits widun wetlands. This cross reference provides a link back to chapter 18.790 to ensure the 
urban foresu-y plan standards are met for Type II and III Sensitive Lands Reviews within wetlands. 
126 
CitY of Tigard Urban l'orcstry Code Rc,·isions I \'olumc II I 130 
Code Amendments 
18.775.070 Sensitive Land Permits 
A. Permits required. An applicant, who wishes to develop within a sensitive area, as defined 
in Chapter 18.775, must obtain a permit in certain situations. D epending on the nature and 
intensity of the proposed activity within a sensitive area, either a Type II or Type III permit is 
required, as delineated in Sections 18.775.020.F and 18.775.020.G. The approval criteria for 
various kinds of sensitive areas, e.g., floodplain, are presented in Sections 18.77 5.070.B-
18.775.070.E below. 
B. Within the 100-year floodplain. The Hearings O fficer shall approve, approve with 
conditions or deny an application request within the 1 00-year floodplain based upon findings 
that all of the following criteria have been satisfied: 
1. Compliance with all of the applicable requirements of this title: 
Renumber 1. through 7. as 2. through 8. 
C. With steep slopes. The appropriate approval authority shall approve, approve with 
conditions or deny an application request for a sensitive lands permit on slopes of 25% or 
greater or unstable ground based upon findings that all o f the following criteria have been 
satisfied: 
1. Compliance with all o f the applicable requirements of this title: 
Renumber 1. through 4. as 2. through 5. 
D . Within drainageways. The appropriate approval authority shall approve, approve with 
conditions or deny an application request for a sensitive lands permit within drainageways based 
upon findings that all o f the following criteria have been satisfied: 
1. Compliance with all of the applicable requirements of this title: 
Renumber 1. through 7. as 2. through 8. 
E. Within wetlands. The Director shall approve, approve with conditions or deny an 
application request for a sensitive lands permit within wetlands based upon findings that all of 
the following criteria have been satisfied: 
1. Compliance with all o f the applicable requirements of this title: 
Renumber 1. through 8. as 2. through 9. 
City of Tigard Urban Forestry Code Rc,·isions I Volume II I 131 
127 
Commentary 
18.775.080 Application Submission Requirements 
Because the urban forestry plan standards are required to be met for Typ e II and III Sensitive 
Lands Reviews, an urban forestry plan is listed in the application submission requirements for Type 
II and III Sensitive Lands Reviews (18.775.020.F and G). 
128 
City of Tigard Urban h>n:>try Code RcYi>ion> I Volume II I 132 
Code Amendments 
18.775.080 Application Submission Requirements 
A. Application submission requirements. All applications for uses and activities identified in 
Sections 18.775.020.A-18.775.020.G shall be made on forms provided by the Director and 
must include the following information in graphic, tabular and/ or narrative form. The specific 
information on each of the following is available from the Director: 
1. A CWS Stormwater Connection permit; 
2. A site plan; 
3. A grading plan; and 
4. An urban forestry plan per chapter 18.790 (for 18.775.020.F and G only); and 
4~. A landscaping plan. 
18.775.090 through 18.775.140 
[No change.] 
Ci ty of Tigard Urban Fores try Code Revisions I Volume II I 133 
129 
Commentary 
18.790 Urban Forestry Plan 
The chapter title has been revised from "Tree Removal" to "Urban Forestry Plan" to better 
reflect the intent of chapter which is to create a plan to enhance the urban fores t through the 
development process rather than to simply remove trees. 
T he guiding principles for Urban Fores try Standards for D evelopment are in Volume I of the 
legislative adoption package for the Urban Forestry Code Revisions. T hese guiding principles 
represent the consensus view o f the citizen advisory committee that advised staff on the Urban 
Forestry Code Revisions. 
18.790.010 Purpose 
The purpose has been simplified to cross re ference the Comprehensive Plan and Urban Fores try 
Mas ter Plan . Both documents provide the detailed policy basis for the extensive revisions to 
Chapter 18.790. 
130 
Cin· of Tigard Urban l'orc>try Code RcYi>ion> I \'olumc II I 114 
Code Am endments 
Chapter 18.790 
T REE REMOVALU RBAN FORESTRY PLAN 
Sections: 
Purpose 
Definitions Applicability 
Tree Plan Urban Forestry Plan Requirem ent§ 
18.790.010 
18.790.020 
18.790.030 
18.790.040 Ineentives for Tree Retention Discretionary Urban Forestry Plan Review 
Option 
18.790.050 Permit 1'\pplieability Flexible Standards for Tree Planting and Preservation 
18.790.060 Illegal Tree Removal Urban Forestry Plan Implementation 
18.790.070 Modification to the Urban Forestry Plan Component of an Approved Land 
Use Permit 
18.790.010 Purpose 
Pumose Th · .e gu~ose f h · 
articulated in the C . . o t ls chapter is to i 1 . omprehenswe Plan as reco d mp ement the City's urban £ mmen ed by the Urba F orestry goals 
n orestry Master Plan. 
Value of trees. Afte£ yea£s of both natmal gmwth and plaft ti:ng by £esideftts, the City n mv 
benefits from a large number of trees. These trees of varied types add to the aesthetic 
beaut) of the con.Itnunitj , help cleaft the air, help cofttrol erosion, maintai11 water quality aHd 
provide Hoise barriers. 
B. Purposes. The purposes of this chapter are to: 
1. Encourage the preserntion, plantillg aftd replacemeft t of trees ill the City; 
2. Regulate the removal of trees Oft seftsitive lands in the City to eli:tfl:i:nate uftnecessal"y 
removal of trees; 
3. Provide for a tfee plan for developing properties; 
4. Protect sensi&..-e lands fwm C£osion; 
5. Protect water quality; 
6. Provide incentives for tree t'eteHtion aftd protection; aHd 
7. Regulate COft'tffierci:al forestt-y to cofttt·ol the removal of trees i11 aft urban envi:ronmeftt. 
C. Recognize Heed for uceptions. The City recognizes that, ftot".vithstaHd:iftg these purposes, at 
the time of developmeftt it may be necessary to remove certam trees in order to 
accommodate structures, streets utilities, aftd other Heeded or reqtli:red i:tnpmvem eHts c;ithin 
the developmeftt. 
131 
City of Tigard Urban ForeRtry Code Revisions I Volume II I 135 
Commentary 
18.790.020 Applicability 
T his section is renamed to Applicability. 
Urban fores tq plans will be required for larger (Typ e II or III) development project types (i\1inor 
Land Partitions, Subdivisions, Conditional Use Permits, Site Development Reviews, Planned 
D evelopments, D owntown D esign Reviews and Sensitive Lands Reviews). 
A fter reviewing exis ting project types and conditions, it was determined that only the larger project 
types identified above have the most consistent and tangible impacts on trees. All o f the larger 
project types currently require tree plans and a project arborist except Type II or III D owntown 
D esign Reviews and Sensitive Lands Reviews. Type II or III Downtown D esign Reviews and 
Sensitive Lands Reviews are similar in scale to the o ther projects, and it would be appropriate to 
require similar tree / urban forestry plan requirements as the other project types. 
The projects with tl1e highest likeW1ood to impact trees and not require an urban fores t plan are 
residential building projects (house additions, retaining walls, landscape grading, etc.). However, a 
review of past residential building projects illustrate that they rarely are designed in ways that 
necessitate tree removal. Also, as demonstrated in the Urban Forestry Master Plan, residential 
property has the highest tree canopy of all zoning types which implies that residential property 
owners are generally good stewards of their tree resources despite a lack of regulations. If increased 
regulations on developed residential properties are identified as necessary in tl1e future as the city 
continues to develop, the code could be revised at tl1at time. 
The current proposal will address the redevelopment o f exis ting commercial, industrial and mL"Xed 
use zones, especially as buildable residential lands in Tigard continue to decrease. The Urban 
Forestry Master Plan demonstrates tl1at exis ting commercial, indusu-ial and ffiL;::ed use zones 
currently have less than half the tTee canopy of residential zones. Staffs proposal is to require 
significant increases in tree canopy tluough redevelopment o f conu11ercial, indusu·ial, and ffiL;::ed use 
zones tluough the urban fores try plan requirements. 
A more flexible urban foresu·y plan modification process is proposed in section 18.790.070 
(i\![odification to the Urban Foresu-y Plan Component of an Approved Land Use Pemut). The 
process allows modifica tions admi.tusu·a tively or truough a Type I pemut depending on tl1e 
magnitude of tl1e modification. The modification process allows applicant to address issues that 
arise dm-ing development such as shifting tree planting locations, adjusting tree protection fence 
location, and removing trees that are no longer feasible to preserve due to condition or location. 
The current code does not provide a process for these types of modifications o ther than tl1rough 
revisions to the ot-iginalland use permit (which is expensive and time conswning). The rationale for 
allowing flexibility in tree removal is to encourage applicants to " take a chance" on preservation 
given the uncertainty of the development process because they know they will have flexibility for 
removal in tl1e future if preservation is no t feasible. The modification process :is more fully 
desct-ibed in section 18.790.070. 
Some development projects (such as trails and utility pro jects) are linUi:ed to t-ight o f ways or 
easements on property the applicant does not o therwise control. In these situations, planting and 
preservation requirements should be linuted to the right of way or easement portion of the property 
the applicant does control. 
1.)2 
Cit~ · of Tiganl Urban h m:s try CoJc Re,·isions I \'olume II I !Vi 
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f n 0 0... 11> ~ 11> ::l 0... 8 11> ::l .... (/) 
Commentary 
18.790.030 Urban Forestry Plan Requirements 
T his section is renamed to Urban Forestry Plan Requirements 
Urban fores try plans are required to be developed by a landscape architect or a person certified 
as bo th an arborist and tree risk assessor. Many arborists are dual certified, and adding the new 
requirement for tree risk assessment will help ensure safe conditions during and after 
construction. Landscape architects often work closely with arborists when developing urban 
forestry plans, so the option o f allowing landscape architects to sign off on the plans has been 
added to reduce costs by eliminating the need for hiring two urban fores try consultants. T he 
urban fores try plan requirements will consist of three m ain parts. 
T he first part, tree preservation and removal site plan, is essentially a demolition / preservation 
plan identifying trees to remain and trees to be removed. The Urban Forestry Manual consists of 
administrative rules to implement the details of the urban fores try related code provisions in 
Title 8, T itle 18 and o ther applicable titles in the Tigard Municipal Code. The detailed 
requirements for the tree preservation and removal site plan are in Section 10, part 1 o f the 
Urban Forestry Manual. T rees over 6 inch diameter, and those trees less than 6 inch diameter 
that are pro tected by Title 8 (street trees, heritage trees, etc.) are required to be shown on the 
plan. Individual trees near the development impact area are required to be individually 
inventoried, but cohesive stands o f trees away from the development impact area can be 
delineated at the edge o f the stand. Tree pro tection fencing is required to be shown on the plan 
as well. The requirements in Section 10, part 1 essentially document the current practice except 
that trees within stands away from the development impact area are no t required to be 
individually inventoried. 
The second part is the tree canopy site plan (Section 10, part 2 of the Urban Forestry Manual). 
This plan shows all trees to be preserved as well as those to be planted. It is essentially a 
landscape plan that includes just the trees. It visually displays how the effective tree canopy 
requirements for the overall development site and individual lots/ tracts will be met. It also 
includes specifications for spacing and placement of trees, measurement of trees, and 
acceptable / prohibited species. 
The third part is the supplemental report (Section 10, part 3 o f the Urban Forestry Manual). 
This is a narrative for the site plans and provides more detailed inventory data on the species, 
size, condition, and suitability o f preservation o f trees and stands o f trees in a more standardized 
format than exists currently. It also contains supplemental preservation and planting 
information to be implem ented during the development process . Finally, it contains the 
standards for determining how the effective tree canopy requirements for the overall 
development site and individual lo ts/ trac ts shall be met. 
(Tree canopy fee continued on following commentary page) 
134 
City of Tigard Urban l;orcstry Code Rc,·isions I \'olumc II I 138 
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Commentary 
18.790.030 Urban Forestry Plan Requirements 
T he tree canopy fee was developed by converting the wholesale median tree cost in the 
Willamette Valley, Oregon developed by the PNWISA ' to a unit canopy cost. Acwrding to the 
PNWISA, the median wholesale cost of a 3-inch diameter deciduous tree is $174. The formula 
developed by Krajicek, et al4 for open grown, broad spreading trees (maximum crown width 
(feet)= 3.183+1.829*DBH (inches)) was then utilized to convert tree diameter to canopy 
diameter. According to the Krajicek formula, a 3-inch diameter tree should have a crown width 
of 8.67 feet or crown area of 59 square fee t. These din1ensions were confirmed as reasonable by 
staff through several local field samples. Using the median cost o f a 3-inch deciduous tree 
($174) and the crown area of a 3-inch diameter tree (59 square feet), the unit canopy cost or tree 
canopy fee should be $2.95 per square foot. 
This methodology is a reasonable approach for three main reasons . First, tree benefits 
(aes thetic, stormwater management, air quality, etc.) are derived primarily from their canopies, so 
proposing to place a value to tree canopy is appropriate. Second, in the proposal, tree canopy is 
valued using the median wholesale tree cost only, whereas standard tree appraisal is based on the 
wholesale tree cost plus the cost of tree installation. Finally, the Krajicek formula and field 
samples by staff are based on the maximum crown width to trunk diameter ratio, and a typical 
tree does not have such a high ratio. If the typical ratio were used, the unit canopy cost would 
mcrease. 
Based on community discussions, the future use o f tree canopy fees (outlined through council 
resolution) should be as follows: 
1. Tree Planting and Early Establishment (50 percent allocation); 
2. Preservation o f exis ting trees following a recommendation approved by majority 
vote of rl1e city board or conunittee designated by ilie city manager to give such 
reconunendations (25 percent allocation); 
3. Maintenance o f those trees planted using ilie Urban Forestry Fund after the early 
establishment period has ended (1 0 percent allocation); 
4. Urban Forestrv E ducation and Outreach following a reconunendation approved by 
majority vote o f ilie city board or committee designated by the city manager to give 
such recommendations (10 percent allocation); and 
5. Urban Forestry Planning for activities iliat support periodic updates o f ilie City o f 
Tigard's Urban Forestry Master Plan, Municipal Code or D evelopment Code 
following a recommendation approved by majority vote of ilie city board or 
committee designated by ilie city manager to give such reconunendations (5 percent 
allocation). 
The planting, early es tablislu11ent and maintenance items should be implemented by staff because 
they are technical in nature. However, deciding how and where to use funds for preserva tion, 
education and outreach and planning should involve a discussion and recommendation by a 
designated board (such as d1e Tree Board) to help ensure expenditures are consistent wid1 
community expectations. 
' Pacific Nordl\vest Chapter of the In ternational Society of ,-\rboriculture. Species Ratings for Landscape Tree 
_-\ ppraisal 2"" Edition, Silverton, OR: Pacific 1'\'orthwest IS.-\ , 2007. 
4 Krajicek, ]. E ., K. E. Btinkman, S. F. Gingrich 1961. Crown Competition - .-\ ""Ieasure of D ensity. Forest Science 
7:35-42. 
1.>6 
City o fTiganJ Urban l'o rc> try Code Rc,·i>iom I \'olumc II I 14U 

Commentary 
18.790.040 Discretionary Urban Forestry Plan Review Option 
This section is renamed to Discretionary Urban Forestry Plan Review Option . 
T he discretionary urban forestry plan review option is an alternative to meeting the clear and 
objective effective canopy requirements. An applicant could make their case at a public hearing 
in front of Planning Commission or the hearings o fficer about how their proposal is an adequate 
substitute for the functions and values o therwise provided by trees. T he functions and values 
provided by trees that may be substituted through alternative means are broken down into three 
main categories: 
1. H ydrological benefits (managing stormwater quantity and quality); 
2. Climate benefits (reducing fossil fuel consumption and carbon emissions when 
appropriately placed for shading, improving air quality through carbon storage and 
absorption of gaseous pollutants, intercepting particulates, etc.); and 
3. Wildlife benefits (food and shelter). 5 
The discretionary option provides examples o f the alternative stormwater management, energy 
efficiency and wildlife enhancement methods that could be presented to the Planning 
Commission or hearings o fficer for consideration as adequate substitutes for the functions and 
values o f trees described above. When deciding whether to approve alternative methods, the 
Planning Commission or hearings officer is encouraged to require certification through a third 
party system (e.g. Earth Advantage, LEED , etc.). 
The review body (Planning Commission or hearings officer) will depend on whether there is a 
concurrent Type III review. For example, if an applicant for a Planned D evelopment (Type III 
Planning Commission review) chooses to receive a discretionary urban fores try plan review, the 
review body will be the Planning Commission. H owever, if an applicant for a Conditional Use 
Permit (Type III hearings o fficer review) chooses to receive a discre tionaty urban forestry plan 
review, the review body will be the hearings o fficer. Finally, if an applicant does no t have a 
concurrent Type III review (e.g. Subdivision, Minor Land Partition, etc.), yet chooses to receive 
a discretionary urban foresuy plan review, the review body will be the hearings o fficer. 
5 McPherson, E.G., S.E . l\Iaco, P.J. Peper, Q. Xiao, A. VanDerZanden, and N . Bell. 2002 Western Washington and 
O regon Commwut:y T ree G uide: Benefi ts , Costs, and Strategic Planting. International Society of / \rboricul ture, 
Pacific N orthwest Chapter, Silverton, OR. 
118 
City of Tigard Urban l'orcstry Code Rc,·isiom I \ 'olumc II I 142 

Commentary 
140 
18.790.040 Discretionary Urban Forestry Plan Review O ption 
The existing incentives for tree retention have been modified to make them more attractive 
to developers and user friendly. They are included in Section 18.790.050. 
City of Tigard Urban 1;orcstry Code RcY isions I \ "olumc 11 I 144 
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Commentary 
142 
18.790.040 Discretionary Urban Forestry Plan Review Option 
The existing incentives for tree retention have been modified to make them more attractive 
to developers and user friendly. They are included in Section 18.790.050. 
City of T igard Urban 1;orcstry Code RcYisiom I \'olumc II I 146 
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Commentary 
18.790.050 Flexible Standards for T ree Planting and Preservation 
T his section is renamed to Flexible Standards for Tree Planting and Preservation. 
Text has been added to the general provisions portion of the section that all the flexible 
standards and incentives supersede conflicting standards in the code unless the flexibility would 
present an unreasonable risk to public health, safety or welfare. 
The director has been authorized to use discretion when granting flexibility. The general 
consensus o f the CAC was to allow applicants to take advantage o f the flexibility without 
requiring a public hearing. 
There are two categories of flexible standards for planting and preservation . T he flexible 
standards in subsection "C" are available for the planting and/ or preservation of all trees . The 
flexible standards in subsection "D " are available only for development sites with a significant 
tree grove. H owever, development sites with significant tree groves are also eligible for all of the 
flexible standards and incentives in subsection "C". 
T he following flexible standards for tree preservation in subsection "C" are proposed to be 
allowed outright without requiring a variance or adjustment: 
• Lot size averaging; 
• Flexible setbacks; 
• Flexible sidewalk locations; 
• r\llowing reductions in minimum parking requirements; and 
• Allowing reductions in rninimum landscape requirements. 
Additional flexibility is included in subsection "C" to facilitate the planting of large stature street 
trees (flexible sidewalk locations such as allowing curb tight sidewalks or allowing sidewalks in 
easements to increase the size of planting strips without losing developable site area). Also 
included is flexibility to reduce competition for space between trees and parking lo ts to facilitate 
the planting o f large stature parking lo t trees (allowing reductions in minimum parking 
requirements when providing canopy through planting). 
T ree removal permit provisions are struck from Chapter 18.790 and revised / relocated to Title 8. 
144 
City of T igard Urban J.'orc, try Code RcY i, ions I \' olumc II I l4H 
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Commentary 
18.790.050 Flexible Standards for Tree Planting and Preservation 
Flexible standards in subsection "C" continued. 
14(> 
City of Tigard Urban l ."orc,try Code Rc,·i, ion' I \'olume II I ISO 
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Commentary 
18.790.050 Flexible Standards for Tree Planting and Preservation 
T he guiding principles for Tree Grove Presetvation Incentives are in Volume I o f the legislative 
adoption package for the Urban Forestry Code Revisions. These guiding principles represent 
the consensus view of the citizen advisory committee that advised staff on the Urban Forestry 
Code Revisions. 
Some base requirements have been included in subsection " D " in order for an applicant to be 
eligible for the additional flexible standards and incentives for preserva tion o f a significant tree 
grove: 
• T here has to be at leas t 10,000 square feet (- 1/ 4 acre) of tree canopy within a 
development site that is part o f a significant tree grove. 
• The 10,000 square feet of significant tree grove canopy is no t already protected by 
floodplain, stream corridor and / or wetland regulations. 
• T he project arborist or landscape architect demonstrates consistency with the 
applicable provisions in the urban fores try plan for the development site. 
If these base requirements are met, there are six flexible standards and incentives that may be 
utilized by the applicant. 
T he fust is a reduction in minin1um density requirements. The applicant will be given the option 
to remove the significant tree grove portion o f their property from their minimum density 
calculations. This will allow applicants to build only on the non-tree grove portion o f their 
property. The applicant would also be required to work with their project arborist or landscape 
architect to designate 50 percent or more o f their tree grove for preserva tion , maxinuze the 
connectivity and viability o f the remaitung portion o f the tree grove and pro tect the remaining 
tree grove through a conserva tion easement or o ther pro tective instrument. 
148 
City of Tigard Urban l'orcHry Code RcTi>ion> I \'olumc II I 152 
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Commentary 
18.790.050 Flexible Standards for Tree Planting and Preserva tion 
The second flexible standard and incentive is residential density transfer. This will allow 
applicants to build attached units and reduce lo t or unit area so they can preserve a significant 
tree grove while building to allowed densities on the non-tree grove portion of the site. In order 
to develop with the 100 percent density transfer, housing types no t typically allowed in lower 
density zones will now be permitted if a tree grove is preserved. T hese housing types include 
attached single family and duplexes. Currently these uses are either not permitted in lower 
density zones, are a conditional use or require a planned development application. The 
proposed changes would allow these uses with the staff level Type II review and no t require a 
public hearing process. 
T he development standards are adjusted accordingly to accommodate smaller lo ts including: 1) 
reduced lot widths; 2) reduced front, side and rear yard setbacks; 3) reduced garage setbacks and 
4) increased building height. 
Lots that abut a developed residential zone with the same or lower density are only allowed a 25 
percent reduction in lot area so they are more compatible with the abutting lots. 
T he applicant would also be required to work with their project arborist or landscape architect 
to designate their tree grove for preservation, maximize the connectivity and viability o f the 
remaining portion of the tree grove, and protect the remaining tree grove through a 
conservation easement or o ther protective instrument. 
1511 
City of Tigard Urban Fores try Code Rc,·isions I \ 'o lumc II I 154 

Commentary 
18.790.050 Flexible Standards for Tree Planting and Preservation 
Table 18.790.1 (Density Transfer T able for Preservation o f Significant Tree G roves) allows 
reduced lo t and unit sizes to facilitate density transfer from the tree grove portion to the non-
tree grove portion of a site. 
152 
CitY of Tigard Urban Forestry Code Re,·isions I \ 'olume II I 156 
Code Amendments 
TABLE 18.790.1 
D ENSITY TRANSFER TABLE FOR PRESERVATION OF SIGNIFICANT TREE 
GROVES 
· Residential 
Zoning 
District 
R-1 
(30 000 sq. 
ft. ner unit! 
R-2 
(20 000 sq. 
ft. ner unit) 
R-3.5 
(10 000 sq. 
ft. n t>r unit! 
R-4.5 
(7 500 sq. 
ft. ner unit! 
R-7 
(5 000 sq. 
ft. ner unit! 
R-12 
(3 050 per 
~ 
R-25 
(1 480 sq. 
ft. per unit) 
R-40 
IN one) 
Detached SO. Attached SO. Duplex Multifamily 
FT.! 
Percent Tree 
G rove Canopy 
Preserved I 
EL 
Percent Tree 
Percent Tree 
Grove Canopy 
Preserved I 
Percent Tree Grove 
Canopy Preserved I 
Min Lot or Unit 
Area 
25 49% I 22 500 sg ft 
50-74% I 15 000 sg ft 
75_100%1 7 500 sg fr 
G rove Canopy 
Preserved I 
Min Lot or 
Unit Area 
N ot Allowed 
Min Lot or Unit 
Area 
N ot Allowed 
25-49% I 15 000 sq. ft I Perm itted with 75% 
50 74% I 1 0 000 sg ft or grea ter tree 1>roye 
75-100% I 5 000 sg ft cano p y m escrya tio n Not Allowed 
I ~ 000 sn ft 
25 49% I 7 500 sg ft Permitted with 75% I Permi tted with 75% 
50-74 °/ o I 5 000 sq ft I or greate r tree P"[OVC o r greate r tree grove 
75-1 00°/o I 2 500 sg ft canopv prese rva tion canopy preservation 
I 2 '100 sa..ft. I ') 000 sn ft 
25-49% I 5 6?5 sg ft Permitted with 75% I Permitted with 75% 
50-74°/o I 3 7 50 sq ft I or grea te r tree p-rove o r greate r tree grove 
75-1 00°/o I 1 875 sg fr canopy grcscrva rj o o ca n o p v preserva tio n 
I U l75 sa . ft.. I 3.750 sn Ft 
?5 49% I 3 750 sg ft. Permitted with 75% I Permitted with 75% 
50-74% I 2 500 sg,_fr,_ o r grea ter tree grove o r grca tc r tree grove 
75-100°/o/ 1 ?50 sg ft I ca no p y preserva tio n I c ano p y presen ,arjo n 
I 1 ? ~0 sa. ft. I 2.500 sn Ft 
Min llnit Area 
Not Allowed 
Not Allowed 
N ot Allowed 
Not Allowed 
Not Allowed 
Single family duplex and multifamily housing permitted at the following densities: 
25-49% tree grove canopy preservation I 2 288 sq. ft. per unit 
50-74% tree grove canopy preservation I 1 525 sq. ft. per unit 
75-100% tree p-rove canonv nreservation I 76_1 sa . ft. n t>r unit 
Single fa mily duplex and multifamily housing permitted at the following densities: 
25-49% tree grove canopy preserva tion I 1 11 0 sq. ft. per unit 
50-74% tree grove canopy presen ration I 740 sq. ft. per unit 
75-100% tree p-rove canonv nreservation I 370 sa . ft. n t>r unit 
Sin I f ·1 g e amty duplex and multifamil h . . yli;i~smg permttted with no upper density 
!53 
City o f Tigard Urban Forestry Code Re,,isions I Volume II I 157 
Commentary 
18.790.050 Flexible Standards for Tree Planting and Preserva tion 
The third and fourth flexible standards and incentives are applicable to commercial and 
industrial development. T hey bo th allow up to 50 percent reduction in minimum setbacks and 
20 feet additional building height for significant tree grove preservation. Buffering and 
screening per Chapter 18.745 would still be required between differing land uses . Maxin10m 
floor area ratio (FAR) in the MUE zoning district supersede the allowed increase in building 
height in that zone. Maxin10m FAR in the MUE zone limits traffic in1pacts on state highway 
facilities. 
The applicant would be required to work with their pro ject arborist or landscape architect to 
designate 50 percent or more o f their tree grove for preserva tion, maximize the connectivity and 
viability o f the remaining portion o f the tree grove and protect the remaining tree grove through 
a consetv ation easement or o ther pro tective instrument. 
!54 
Ciry of Tiganl Urban l;orcstry Code Rc,·isions I \'olumc II I !58 
Code Amendments 
3. Adjustments to Commercial Development Standards. Adjustments to 
Commercial Development Standards (Table 18.520.2) of up to 50 percent reduction in 
minimum setbacks and up to 20 feet additional building height are permitted provided: 
~ At least 50 percent of a significant tree grove's canopy within a 
development site (and not also within the sensitive lands wes in Section 18.775.010(G)(1-3)) is 
preserved; 
b.... The project arborist or landscape architect certifies the 
preservation is such that the connectivity and viability of the remaining significant tree grove is 
maximized while balancing the considerations in Section 10 part 5 of the Urban Forestry 
Manual; 
,k Applicable buffering and screening standards in Section 
18.745.050 are met; 
d.,_ Any height adjustments comply with the International Building 
~ 
~ Maximum floor area ratio is not exceeded in the MUE zoning 
district as described in Section 18.520.050.C.1; 
f. Any setback reduction is not adjacent to residential zoning: and 
& The significant tree grove is protected through an instmment or 
action sub ject to approval by the director that demonstrates it will be permanently presetyed and 
managed such as: 
(i) A conservation easement; 
(ii) An open space tract; 
(iii) A deed restriction; or 
(iv) Through dedication and acceptance by the city. 
4. Adjustments to Industrial Development Standards. Adjustments to 
Development Standards in Industrial Zones (Table 18.530.2) of up to 50 percent reduction in 
minimum setbacks and up to 20 feet additional building height are permitted provided: 
a. At least 50 percent of a significant tree grove's canopy within a 
development site (and not also within the sensitive lands wes in Section 18.775.010(G)(1-3)) is 
preserved; 
The roject arborist or landscape a~cl~tect certifie~ t~e 
b. ~ · d iabili 1 of the remaining s1gmficant tree gxove Is 
preservation is such that _the connectl~lty a~ v . iection 10 part 5 of the Urban Forestry 
. . d bile balancmg the considerations m maximize w 
Manual.; 
c. Applicable buffering and screening standards in Section 
18.745.050 are met; 
d. Any height adjustments comply with the International Building 
~ 
e. Any setback reduction is not adjacent to residential zoning: and 
ISS 
City of Tigard Urban )!ores try Code Revisions I Volume II I 1S9 
Commentary 
18.790.050 Flexible Standards for Tree Planting and Preserva tion 
T he fifth flexible and incentive based standard is an adjustment to the minimum effective 
canopy requirement. A standard urban fores try plan requires 15 percent effective tree canopy in 
the R-1, R-2, R-3 .5, R-4.5 and R-7 districts per lo t in addition to the overall development site 
effective canopy requirement which is based on zoning (25, 33 or 40 percent). In order to 
facilitate the preservation of significant tree groves, the " per lot" effective canopy requirement 
could be waived. T his could benefit development that uses density transfer and reduced lo t sizes 
to preserve a significant tree grove by not requiring trees on individual lo ts as long the overall 
development site meets the zoning specific canopy requirement. T he applicant would be 
required to work with their project arborist to designate 50 percent of their tree grove for 
preservation, maximize the connectivity and viability o f the remaining portion of the tree grove 
and protect the remaining tree grove through a conservation easement or other protective 
instrument. 
T he final flexible and incentive based standard is an adjustment to the street and utility 
standards. The intent is to highlight the director's authority in Chapter 18.810 to vary from 
street and utility standards to preserve natural fea tures (such as a significant tree grove) provided 
the adjustment does no t result in an unreasonable risk to public safety. In addition, variation 
from the street tree standards in Chapter 18.7 45 would be permitted to facilitate the preserva tion 
of a significant tree grove. T he project arborist would be required to show that the variation 
from the standards will facilitate preserva tion and help to maxim.ize the connectivity and viability 
of a significant tree grove. T he applicant would also be required to protect the remaining tree 
grove through a conservation easement or other protective instrument. 
15(, 
Citr of Tigan.l Urban I 'ore, try Code Rc,·i,ion' I \' olumc II I 160 
<
 
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.. 
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 >
 
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Commentary 
18.790.060 Urban Foresu·y Plan Implementation 
T he urban fores try plan implen'lentation requirements standardize the inspection and 
documentation requirements currently administered through conditions of development 
approval. 
T he general provisions section states that urban fores try plans are in effect from the point of 
land use approval until all applicable urban fores try plan conditions o f approval and code 
requirements have been met (typically after planted trees have met their two year es tablishment 
requirement). T he reason for requiring an end point for the effective period o f an urban 
forestry plan is to allow future permitting decisions to occur through the regulatory framework 
in Title 8 (rather than as a modification to a previous land use decision). 
!58 
City or Tigan.l Urban Forcs Lry CO<k Rc,·isions I \' olumc 11 I I (,2 

Commentary 
18.790.060 Urban Fores try Plan Implementation 
T he o ther implementation elements include regular inspections of tree protection during 
development, two years o f tree es tablishment for newly planted trees, and an inven tory of trees 
and stands of trees for the city's G IS database. The tree protection inspection requirements 
conform to current requirements implemented through conditions of development approval. 
T he tree es tablishment requirements allow for bonding of newly planted trees during the 
es tablishment period, require replacement o f trees that die and require a renewal o f the bonding 
period if less than 80 percent of the planted trees survive (replacement o f trees is required even 
if over 80 percent survive). The details of the inspection and tree establishment requirements are 
included in Section 11 of the Urban Fores try Manual. 
The urban fores t inventory requirements are in Section 11 o f the Urban Forestry Manual as well, 
and require trees to be included in a publicly accessible G IS database. T his could allow people 
to type in their address and find information about the pro tected trees on their property from 
the city's website. T lus will make information retrieval for bo th the city and public easier than 
through other instruments such as deed res trictions. Section 11 of the Urban Forestry Manual 
allows the city to charge a fee to cover its cost o f collecting and processing the urban fores t 
inventory data. 
T ree removal pernut provisions are struck from Chapter 18.790 and revised / relocated to Title 8. 
l lill 
City ofTiganJ Urban Forestry Code Re,·isions I \'olumc II I 164 
n
 
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. 
(1)
 >
 
8 (1) :::3 0... 8 (1) :::3 .... "' 
Commentary 
18.790.060 Urban Forestry Plan Implementation 
Tree removal permit provisions are struck from Chapter 18.790 and revised / relocated to Title 8. 
162 
City of Ti~-,r.~ rd Urban l;orcsLry Code RcY isions I \ 'olumc II I 166 
=
 
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. 
(b
 >
 
8 (b ::l 0..
 
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Commentary 
18.790.070 
Permit 
Modification to the Urban Fores try Plan Component of an Approved Land U se 
Two levels o f modifica tions to the urban fores try plan component of an approved land use 
permit will be allowed. Minor modifica tion to will be completed as a staff level, technical 
review. The fo llowing items would be considered minor modifications: 
• Removal o f hazard trees if there is sufficient documentation by a certified tree 
risk assessor; 
• Modification o f the quantity, location or species o f trees to be planted, provided 
the same or greater tree canopy will result; 
• Modification o f the location o f tree pro tection fencing, provided the arborist or 
landscape architect certifies that the viability of the trees will not be impacted; 
• Modi fying any o ther site elements (e.g. paving, building, etc.) that do no t also 
require a modification to the loca tion o f the tree protection fencing; and 
• Maintenance o f trees (pruning, mulching, fertilization, etc.) in accordance with 
tree care industry standards. 
Significant modifications to the urban forestry plan component o f an approved land use permit 
such as cutting down existing trees and replacing them with new trees will be required to be a 
Type I land use decision . Type I decisions are clear and objective decisions and do not require 
no tice o f the surrounding neighbors. The criteria for approving such modifications are: 
164 
• The project arborist or landscape architect has provided a report certifying that 
trees are being removed due to unforeseen circumstances; 
• The project arborist or landscape architect has provided a report certifying that 
there is no practicable alternative to tree rem oval; and 
• T he project arborist or landscape architect demonstrates that the canopy 
requirement will be met through a revised plan . 
CitY of Tigard Urban Forestry Code Rc,·isions I \'olumc II I )(,8 

Commentary 
18.790.070 
Pennit 
Modification to the Urban Forestry Plan Component o f an Approved Land Use 
Modifica tion procedures continued. 
1 (,(, 
City of Tigard Urban l'orc>try Code RcYisiom I \'olumc II I 170 
<
 
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Commentary 
18.790.070 
Permit 
Modifica tion to the Urban Forestry Plan Component o f an Approved Land Use 
Modification procedures continued. 
18.790.060 Illegal Tree Removal 
T his section is struck. 
Tree violations are now consolidated with o ther nuisance violations in Title 6. Violations o f the 
new Title 8 (Urban Foresu·y) are also consolidated into Title 6. 
Penalties for tree violations are in Chapter 1.1 6 where o ther penalties are already consolidated. 
Penalties for violations o f Title 8 (Urban Forestry) are also outlined in Chapter 1.1 6. 
T he details of tree violations and penalties for tree violations are in T itle 6 and Chapter 1.1 6 
respectively. 
l ot\ 
City of Tigard Urban J.'ore,tn· Code Rc,·i,ions I \ 'olumc II I 172 
<
 
0 c
 3 " 
n
 
0 0..
. 
11>
 >
 
8 11> ::l 0... 8 11> ::l M [J) 
Commentary 
18.790.060 Illegal Tree Removal 
Strikethroughs o f existing code language continued. 
170 
City of Tigard Urban l;orc>try C:ouc Rc,·i>iom I \'olumc II I 174 

Commentary 
18.790.060 Illegal Tree Removal 
Strikethroughs of existing code language continued. 
172 
City of Tigard Urban l'orcstry Code Rc,-isiom I \'olumc II I 17(, 

Commentary 
18.798 WIRELESS COMMUNICATION FACILITIES 
In Chapter 18.798, the term "registered" has been changed to "certified" to reflect International 
Society of Arboriculture terminology. 
1 7~ 
City of Tigard Urban Forc,try Code Rc,·i,iom I \ 'o lumc II I 17R 
Sections: 
18.798.010 
18.798.020 
18.798.030 
18.798.040 
18.798.050 
18.798.060 
18.798.070 
18.798.080 
18.798.090 
Chapter 18.798 
WIRELESS COMMUNICATION FACILITIES 
Purpose 
Definitions 
Exemptions 
Uses Permitted Outright 
Uses Subject to Site Development Review 
Uses Permitted Subject to Conditional Use Review 
Submission Requirements 
Collocation Protocol 
Abandoned Facilities 
18.798.010 through 18.798.040 
[No change.] 
18.798.050 Uses Permitted Subject to Site Development Review 
A. [No change.] 
Code Amendments 
B. Review criteria. Any use subject to Site D evelopment Review per Subsection A above, shall be 
evaluated using the following standards: 
1. through 6. 
[No change.] 
175 
City of Tigard Urban Forestry Code Revisions I Volume II I 179 
Commentary 
18.798.050 Uses Permitted Subject to Site D evelopment Review 
T he term "registered" has been changed to "certified" to reflect International Society o f 
Arboriculture terminology. 
17(, 
City of Tigard Urban l'orc, try Code Rc,·ision' I \'olumc II I HID 
Code Amendments 
7. Landscaping and screening. 
a. Landscaping shall be placed outside the fence and shall consist of evergreen shrubs 
which reach six feet in height and 95% opacity within three years of planting; 
b. When adjacent to or within residentially-zoned property, freestanding towers and 
accessory equipment facilities shall be screened by the planting of a minimum of four 
evergreen trees at least 15 feet in height at the time of planting. The planting of said 
trees shall be prescribed in number by a plan prepared by a regisl'ered certified arborist 
in locations that (1) most effectively screen the wireless facilities from residential uses 
and (2) promote the future survival of the trees while limiting adverse effects of the 
trees on abutting properties. Exis ting evergreen trees at least 15 feet in height may be 
used to meet the screening requirement of this section if the arborist demonstrates that 
they provide screening for abutting residential uses. 
8. [No change.] 
C. [No change.] 
18.798.060 Uses Permitted Subject to Conditional Use Review 
A. [No change.] 
B. Review criteria. Any use subject to review per Subsection A above, shall be evaluated using the 
following standards: 
1. through 6. 
[No change.] 
177 
City of Tigard Urban Forestry Code Re,-isions I Volume II 1 181 
Commentary 
18.798.060 Uses Permitted Subject to Conditional Use Review 
The term "registered" has been changed to "certified" to reflect Intem ational Society o f 
Arboriculture terminology. 
178 
City of Tigard Urban Fores try Code RcYisions I \'olumc II I 182 
Code Amendments 
7. Landscaping and screening. 
a. Landscaping shall be placed outside the fence and shall consist of evergreen shmbs which 
reach six-feet in height and 95% opacity within three years of planting. 
b . When adjacent to or within residentially-zoned property, free-s tanding towers and 
accessory equipment facilities shall be screened by the planting of a minimum of four 
evergreen trees at least 15 feet in height at the time of planting. The planting of said trees 
shall be prescribed in number by a plan prepared by a registered certified arborist in 
locations that (1) most effectively screen the wireless facilities from residential uses and (2) 
promote the future smvival of the trees while limiting adverse effects of the trees on 
abutting properties. Existing evergreen trees at least 15 feet in height may be used to meet 
the screening requirement of this section if the arborist demonstrates that they provide 
screening for abutting residential uses. 
8. [No change.] 
C. [No change.] 
18.798.070 through 18.798.090 
[No change.] 
179 
City o fTigard Urban Forestry Code ReYisions I Volume II I 183 

Urban Forestry Code Revisions 
Peer Review 
City of Tigard Urban Forestry Code ReYisions I Volume II 1 185 
u
 
E ::l 
0 ::.-
To: 
City of Tigard 
Memorandum 
Planning Commission and City Council 
From: Todd Prager, Associate Planner/ Arborist 
R e: Urban Forestry Code Revisions Peer Review 
Date: October 20, 2011 
Introduction 
In February 2010, council directed staff to pursue a comprehensive update of the city's urban forestry 
code provisions. The original scope of work included a peer review phase to test the draft code by a 
panel of development and urban forestry experts. AKS Engineering and Forestry specializes in both 
development and urban forestry with in-house expertise in civil engineering, forestry, land surveying, 
landscape architecture, planning, and arborist services. AKS collaborated with staff on developing the 
draft Urban Forestry Manual, which contains specifications and examples of how to implement the 
draft urban forestry code provisions. Based on past work performance and their familiarity with the 
draft code, staff selected AKS to provide the peer review services for testing the draft code. 
Purpose 
The purpose of the peer review is to test the draft urban forestry code provisions and specifications in 
chapter 18.790 (Urban Forestry Plan), 18.745 (Landscaping and Screening), and the draft Urban 
Forestry Manual using a set of actual development projects in or near Tigard. This will help staff, 
policymakers, and citizens identify the feasibility of the draft code provisions, and any key issues that 
need to be addressed prior to the legislative adoption phase beginning in January 2012. 
Scope/Process 
1. City staff worked with AKS to identify sL-x: actual development projects that are typical of the range 
of projects found in Tigard. The projects are: 
o Tigard Distribution Center - Industrial Parking Lot Expansion on Hunziker Street 
o Max's Brew Pub- Downtown Tigard Commercial Parking Lot Expansion 
o Broadway Rose- Performing Arts Center on a School Property (CF Tigard Elementary) 
o Sequoia Landing- Alley Loaded Townhomes in High Density Residential* 
o Bull Mountain View Estates - 10 Lot Subdivision in Low Density Residential 
o Masters Partition - Three Lot Partition in Medium Density Residential** 
*This site is in Oregon City with R-40 equivalent zoning. 
**This site is in unincorporated Washington County on Bull Mountain with R-7 equivalent zoning. 
2. AKS obtained CAD flies which contain the approved site plans for each of the projects. 
City of Tigard Urban Forestry Code Re,-isions I Volume II I 187 
3. Using the CAD flies, AKS created Tree Canopy Site Plans and associated arborist reports using the 
draft code and Urban Forestry Manual standards to evaluate whether the draft standards are 
achievable and contain any unintended consequences. Some modifications to the existing CAD 
flies such as moving planted tree locations, showing additional planted trees, modifying the 
dimensions and/ or locations of planting areas (such as parking lot islands and planter strips), 
identifying areas where covered soil volumes would be required, to ensure the draft code standards 
were met. However, AKS did not make any major revisions to the CAD flies such as changing 
building sizes or locations, or re-engineering of the projects sites. 
4. AKS then submitted the Tree Canopy Site Plans and associated arborist reports for review and 
"approval" by city staff using the draft code and Urban Forestry Manual standards. After some 
minor revisions, each project was "approved" by city staff. 
Results 
Site Zoning/Use %Effective % Effective % Parking Lot % Parking Lot 
Canopy Canopy Canopy Canopy 
Reg uired Achieved Reg uired Achieved 
Tigard Light Industrial 25% 26% 30% 45% 
Distribution (1-L) 
Center 
--Max's Brew Pub Downtown 25% 42% 30% 31 % 
(MU-CBD) 
Broadway Rose School Use 25% 26% --30% 42% 
Sequoia High Density Res. 33% 35% N/ A N/ A 
Landing (R-40 e9uivalent) 
Bull Mountain Low Density Res. 40% 45% N/A N/A 
View Estates (R-4.5 
Master's Med. Density Res. 40% 215% N/ A N/ A 
Partition (R-7 equivalent) 
Findings 
All si.-x project sites were able to meet the applicable minimum effective canopy requirements through 
various combinations of tree planting and preservation. Sites with parking lots were able to meet the 
30% minimum canopy requirement direcdy over parking lots, and sites with multiple lots were able to 
meet the 20% minimum effective canopy requirement per lot. All of the additional draft urban forestry 
standards such as species selection, soil volume requirements, tree spacing, utility setbacks and building 
setbacks were reviewed and met for each of the sites. The required number of street trees was 
provided for each of d1e sites as well. 
Based on their experience applying the draft urban forestry standards, AKS provided the city a peer 
review which is included in Attachment 7. There were a number of items in the draft code that AKS 
thought worked well. First, they found the code provided enough flexibility for the project designer to 
meet the canopy standards while allowing for an aesthetically pleasing result. They also found the code 
to be equitable in that it did not overly burden property owners with existing trees. Finally, they 
thought the soil volume standards and planting requirements will result in long success of newly 
planted trees and reduce future conflicts with infrastructure. 
City of T igard Urban l'orc>try Code Rc,-i>iom I \'olumc II I IRH 
There were a number of items in the draft code that AKS thought could be improved. These included 
repetition of submittal requirements which were unnecessary and would increase project costs, lack of 
clarity about calculation methods and submittal requirements, and lack of flexibility on tree placement 
for more densely developed residential sites. AKS provided the city with a list of recommended 
additions and clarifications for the draft code based on these issues. Staff addressed each of the 
additions and clarifications, and revised the draft code as needed. 
AKS provided input on issues with the draft code that are difficult to determine at present, but should 
be monitored after implementation. They estimated the draft code did not necessarily require more 
trees than the existing code, so the change in landscaping cost is likely to be negligible. However, if 
covered soil volumes are used to meet the requirements, landscaping costs could increase. This could 
occur when retrofitting commercial and industrial sites with a high percentage of paving. However for 
new commercial and industrial sites, less hardscape may result from increased landscape areas thus 
reducing costs associated with paving. 
\KS estimated the difference in cost benefits to property owners between developing a treed versus an 
un-treed lot would be negligible. This is because although the code provides bonus credits for 
preservation, there are also costs associated with preserving trees. For sites without existing trees, more 
trees would need to be planted than on sites with existing trees. The negligible difference in developing 
a treed versus an un-treed lot is in contrast to the existing code where mitigation requirements 
significantly increase the cost of developing treed lots . 
AKS found the potential for an overreliance on large canopy deciduous trees that are on the city's 
approved tree lists. This could result in decreased plant diversity over time. They also thought double 
credit for preservation could incentivize the preservation of trees that may not be able to witl1stand 
construction impacts. The last issue AKS recommended monitoring is whether parking lot paving 
would be extended in some instances to capture the canopy area of existing trees to meet parking lot 
canopy cover requirements. 
Conclusion 
The draft urban forestry standards for development have been shown to be achievable on a range of 
typical development sites in Tigard. The peer review demonstrates that the draft standards provide 
flexibility for project designers to achieve an aesthetically pleasing and sustainable result, while not 
overly burdening property owners with existing trees. The peer review also exposed a number of issues 
with the draft code including repetitive and unclear standards. These issues have been addressed by 
staff though additional revisions and clarifications. Finally, there are a number of potential implications 
of the draft code that should be monitored. These include the potential for increased costs if covered 
soil volumes are relied upon, decreased species diversity if certain species are favored, preservation of 
non-viable trees, and additional parking lot paving to meet parking lot canopy requirements. If proven 
to be significant after implementation, the urban forestry standards could be modified to correct the 
1ssues. 
Attachments 
Attachment 1 
Attachment 2 
Attachment 3 
Attachment 4 
Tigard Distribution Center Tree Canopy Site Plan 
Max's Brew Pub Tree Canopy Site Plan 
Broadway Rose Tree Canopy Site Plan 
Sequoia Landing Tree Canopy Site Plan 
City of Tigard Urban Fores try Code Revisions I Volume II I 189 
Attachment 5 
Attachment 6 
Attachment 7 
Bull Mountain View Es tates Tree Canopy Site Plan 
Master's Partition Tree Canopy Site Plan 
Peer Review by AKS Engineering and Fores try 
Cit} of Tigard Urban l'orcstry Code Rc,·isions I \'olume II I I'!D 
SCALE ! " ~ 40 FEET 
---~ .P""\ " ~ 
WETlAND 
\ / 
;( ---.-----
TREE LEGEND 
----~=-------------~~XZJ 
Bt.LDI«) 
A 
82.430 SQFT. 
' ... , ~MATURE CANOPY COVER {TYP.) 
'("' APPROX. LIMIT OF PARKING LOT 
\ / CANOPY (TYP.) 
I 
I 
BlJI...DI«l 
SYMBOL QTI ES. 
®12 
® 9 
BOTANICAL NAME COMMON NAME 
CERCIS CANADENSIS EASTERN REDBUD 
CONDITION SIZE 
B&B 
SPACING 
2" CAL AS SHOWN ~//7/d-, 5 ; - ~ • 
EXISTING BUILDING / // T/ff~ r- I /.____ 
~13 014 
CORN US KOUSA KOUSA DOGWOOD 
FRAXINUS PENNSYLVANICA GREEN ASH 
ULMUS 'MORTON' ACCOLADE ELM 
TREE CANOPY TABLE 
B&B 2· CAL AS SHOWN 
B&B 2· CAL AS SHOWN 
B&B 2" CAL AS SHOWN 
NOTES: 
1. TREE PlANTING SPECIFICATION S: REFER TO SUPPLEMENTAL ARBORIST REPORT. 
2. IMPROVE AREAS WITH TREE GROWTH LIMITING SOILS; REFER TO SUPPLEMENTAl ARBORIST 
REPORT FOR SPECIFtcATIONS. 
TREE # SPECIES OPEN SOIL VOLUME COVERED SOIL VOLUME TOTAL SOIL VOLUME AVE. MATURE CANOPY % CANOP Y OVER PARKING LOT 
39% 
AREA OVER PARKING LOT QUALIFYING SITE CANOPY 
001 
002 
003 
004 
005 
006 
007 
008 
009 
010 
011 
012 
013 
014 
015 
016 
017 
018 
019 
020 
021 
022 
023 
024 
025 
026 
027 
028 
029 
030 
031 
032 
033 
034 
035 
036 
037 
Accolade Elm 
Eastern Redbud 
Green Ash 
Eastern Redbud 
Eastern Redbud 
Accolade Elm 
Eastern Redbud 
Green Ash 
Eastern Redbud 
Accolade Elm 
Eastern Redbud 
Green Ash 
Accolade Elm 
Accolade Elm 
Accolade Elm 
Eastern Redbud 
Green Ash 
Eastern Redbud 
Green Ash 
Green Ash 
Accolade Elm 
Accolade Elm 
Green Ash 
Accolade Elm 
Green Ash 
Eastern Redbud 
Accolade Elm 
Accolade Elm 
Green Ash 
Green Ash 
Accolade Elm 
Green Ash 
Accolade Elm 
Eastern Redbud 
Eastern Redbud 
Accolade Elm 
Green Ash 
Owr 1,uou c .T. 
Owr 1,000 c .f. 
237 c .f. 
Owr 1,000 c . f. 
Owr 1,000 c . f. 
Owr 1,000c.f. 
Owr 1,000 c.f. 
Owr 1,000 c.f. 
Owr 1,000 c .f 
576 c .f. 
Owr 1,000 c . f. 
Owr 1,000 c . f. 
Owr 1,000 c.f. 
Owr1 ,000c.f. 
Owr 1,000 c.f. 
Owr 1,000 c.f 
0\6r 1,000 c.f 
Owr 1,000 c.f. 
0\6r 1,000 c f. 
0\6r 1,000 c . f. 
Owr 1,000 c.f. 
Owr 1,000 c.f. 
Owr 1,000 c.f 
384 c .f 
0\6r 1,000 c.f 
Owr 1,000 c.f 
Owr 1,000c.f 
699 cf. 
Owr 1,000 c.f 
Owr 1,000 c.f 
Owr 1,000c.f. 
Owr 1,000 c.f. 
Owr 1,000 c .f. 
Owr 1,000 c .f 
Owr 1,000 c.f 
Owr 1,000c .f. 
Owr 1,000 c.f 
0 c.f. 
0 c.f. 
795 c.f. 
0 c.f. 
0 c.f. 
0 cf. 
0 c.f. 
0 c.f. 
0 c.f. 
864 c.f. 
0 c.f 
0 c.f. 
0 c.f 
0 c.f. 
0 c.f 
99 c .f. 
243 c.f 
390 c .f. 
150 c.f 
0 c.f. 
0 c.f. 
0 c.f. 
0 c.f. 
984 c.f. 
0 c .f. 
198 c .f. 
Oc.f 
804 cf. 
Od 
Od 
Oc .f. 
Oc .f. 
Oc.f 
Oc .f. 
Oc .f. 
0 cf 
Oc.f 
Owr 1,000 c .f. 
Owr 1,000 c . f. 
1,032 c. f. 
0-.er 1,000 c .f 
Owr 1,000 c .f 
Owr 1,000 c. f. 
0-.er 1,000 c. f. 
Owr 1,000 c.f. 
Owr 1,000 c.f. 
1,440 c .f. 
Owr 1,000 c . f. 
Owr 1,000 c . f. 
Owr 1,000 c.f 
Owr 1,000 c.f. 
Owr 1,000 c.f. 
Owr 1,000 cf. 
Owr 1,000 c.f. 
Owr 1,000 c.f. 
Owr 1,000 c.f. 
Owr 1,000 c . f. 
Owr 1,000 c . f. 
0-.er 1,000 c . f. 
0-.er 1,000 c .f. 
1,368 c .f. 
Owr 1,000 c.f. 
Owr 1,000 c.f. 
0-.er 1,000 c.f. 
1,503 c. f. 
0-.er 1,000 c . f. 
0-.er 1,000 c . f. 
Owr 1,000 c . f. 
Owr 1,000 c . f. 
Owr 1,000 c . f. 
0-.er 1,000 c . f. 
Owr 1,000 c.f. 
Owr 1,000 cf. 
Owr 1,000 cf 
60' spread (2 ,826 s.f.) 
25' spread (491 s .f.) 
40' spread (1 ,256 s.f.) 
25' spread (491 s .f.) 
25' spread (491 s .f.) 
60' spread (2 ,826 s.f.) 
25' spread (491 s.f.) 
40' spread (1,256 s.f.) 
25' spread (491 s .f) 
60' spread (2,826 s .f.) 
25' spread (491 s.f.) 
40' spread (1,256 s.f.) 
60' spread (2,826 s.f.) 
60' spread (2,826 s .f.) 
60' spread (2,826 s .f.) 
25' spread (491 s.f.) 
40' spread (1 ,256 s .f.) 
25' spread (491 s .f.) 
40' spread (1,256 s .f.) 
40' spread (1 ,256 s .f.) 
60' spread (2,826 s .f.) 
60' spread (2.826 s .f.) 
40' spread (1 ,256 s .f.) 
60' spread (2,826 s.f.) 
40' spread (1 ,256 s.f.) 
25' spread (491 s .f.) 
60' spread (2,826 s.f.) 
60' spread (2,826 s .f.) 
40' spread (1 ,256 s.f) 
40' spread (1 ,256 s .f.) 
60' spread (2,826 s.f.) 
40' spread (1 ,256 s.f.) 
60' spread (2,826 s.f.) 
25' spread (491 s .f.) 
25' spread (491 s .f.) 
60' spread (2,826 s .f.) 
40' spread (1 ,256 s f) 
SITE TREE 
CANOPY PLAN 
25% 
85% 
100% 
100% 
26% 
23% 
79% 
30% 
100% 
40% 
100% 
31% 
38% 
41% 
17% 
BO"k 
15% 
80"k 
84% 
100% 
100% 
100% 
100% 
100% 
100% 
100% 
86% 
72% 
68% 
100% 
79% 
100% 
28% 
29% 
40"k 
39% 
1,10'L S.l. 
124 s.f. 
1,067 s.f. 
491 s.f. 
491 s.f. 
729 s.f. 
114 sf. 
986 s.f. 
148 s.f 
2,826 s.f. 
197 s .f. 
1,256 s.f. 
870 s.f. 
1,062 s.f. 
1,165 s.f. 
83 s.f. 
1,007 s.f 
75 s.f. 
1,005 s .f. 
1,049 s .f. 
2,826 s.f. 
2,826 s.f. 
1,256 s.f. 
2,826 s.f. 
491 s.f. 
491 sf. 
2,826 sf. 
2 ,431 s.f. 
901 s.f. 
851 s.f. 
2,826 s .f. 
987 s.f. 
2,826 s.f. 
137 s.f 
142 s.f. 
1,140 s.f. 
488 sf. 
2,826 s.f. 
491 s.f. 
1,256 s.f. 
491 s.f. 
491 s.f. 
2,826 s.f. 
491 s.f. 
1,256 s.f. 
491 s.f. 
2,826 s.f. 
491 s .f. 
1,256 s.f. 
2,826 s.f. 
2,826 s.f. 
2,826 s.f. 
491 s .f. 
1,256 s.f 
491 s .f. 
1,256 sf 
1,256 s.f. 
2,826 s.f. 
2,826 s.f. 
1,256 s.f. 
2,826 s.f. 
1,256 s.f. 
491 sf. 
2,826 sf. 
2,826 sf. 
1,256 sf. 
1,256 s.f. 
2,826 s.f. 
1,256 s.f. 
2,826 s.f. 
491 s.f. 
491 s.f. 
2,826 s.f. 
1,256 s.f. 
ENCltEERINQ Pl..MI'.Hl SURVEYNG 
UCENSID • OR. WU AK • 
1~910 SW GAlllREA TH DR., 9JI1E 100 
SHERVrOOO, DR 97140 A 
Pf!OO[; (50J) 92!;-8799 
rAJ< (50J) 92!;-8969 orcomrrrc • "''''"" 
Offices locoted ~: 
SHERVrOOO. OREGON 
REDIIOND, OREGON 
VANCOJ'oU!. WASHNGTON 
....... oks-eng.com 
TREE I/. 
038 
039 
040 
041 
042 
043 
044 
045 
046 
047 
048 
SPECI ES 
Eastern Redbud 
OPEN SOIL VOLUME COVERED SOIL VOLUME TOTAL SOI L VOLUME AVE. MATURE CANOP Y 
25' spread (491 s.f. ) 
40' spread (1 ,256 s.f.) 
25' spread (491 s.f.) 
25' spread (491 s.f.) 
25' spread (491 s.f.) 
25' spread (491 s.f.) 
25' spread (491 s.f.) 
25' spread (491 s.f.) 
25' spread (491 s.f.) 
25' spread (491 s.f.) 
25' spread (491 sf.) 
0-.er 1,000 c f. 0 c.f. Owr 1,000 c .f. 
Green Ash 
Kousa Dogwood 
Kousa Dogwood 
Kousa Dogwood 
Kousa Dogwood 
Kousa Dogwood 
Kousa Dogwood 
Kousa Dogwood 
Kousa Dogwood 
Kousa Dogwood 
EXISTING TREE CANOPY 
TREE# 100~101 4 ; 1016-1019 
Owr 1,000 c . f. 
Owr 1,000c .f. 
Owr 1,000 c .f. 
Ow r 1,000 c .f. 
Owr 1,000 c .f. 
Owr 1,000 c .f. 
0-.er 1,000 c.f. 
0-.er 1,000 c.f. 
Owr 1,000 c.f. 
Owr 1,000 cf. 
EXISTING TREE CANOPY OVER PARKING LOT 
TREE# 1016, 1017, 1018, 1019 
D QUALIFYING MATURE CANOPY COVER 
INDIVIDUAL TREE MATURE CANOPY OUTLINE 
~ EXISTING TREE CANOPY OUTLINE 
Od 
Od 
Od 
Od 
Od 
Od 
Od 
Ocf. 
Ocf. 
0 c.f 
Owr 1,000c.f. 
Owr 1,000c.f 
Owr 1,000 c.f. 
Ow r 1,000 c.f. 
Owr 1,000 c.f. 
Owr 1,000 c.f. 
Owr 1,000c.f 
Owr 1,000 c .f. 
Owr 1,000 c.f 
0-.er 1,000 c f 
• OPEN SOIL VOLUME 
COVERED SOIL VOLUME 
TOTAL SITE AREA: 280,090 S.F. PARKING LOT AREA: 98,617 S.F. 
TOTAL QUALIFYING MATURE TREE CANOPY AREA: 73 ,449 S.F. TOTAl QUALIFYING MATURE TREE CANOPY AREA: 44,447 S.F. 
% CANOPY COVER: 26% 0k CANOPY COVER: 45% 
MINIMUM % CANOPY COVER: 25% MINIMUM % CANOPY COVER: 30% 
26% IS GREATER THAN THE MINIMUM OF 25% TOTAL QUALIFYING MATURE CANOPY COVER FOR THE SITE, THEREFORE CITV 
REQUIREMENTS ARE MET. ADDITIONALLY. THERE IS 32% CANOPY COVER OVER THE PARKING LOT, EXCEEDING THE REQUIRED 
30% COVERAGE. 
% CANOPY OVER PARKING LOT 
70% 
AREA OVER PARKING LOT QUALIFYING SITE CANOPY 
342 s.f. 491 s.f. 
44% 
Not Panting lot Tree 
Not Panting l ot Tree 
Not Pant ing lot Tree 
Not Panting lot Tree 
Not Parking l ot Tree 
Not Parking lot Tree 
Not Parking lot Tree 
Not Perking lot Tree 
Not Park ing lot Tree 
550 s.f. 
NA 
NA 
NA 
NA 
NA 
NA 
NA 
NA 
NA 
SITE CANOPY SUBTOTAL 
CANOPY OVER PARKING LOT SUBTOTAL 
1,256 sf. 
491 s.f. 
491 s .f. 
491 s .f. 
491 s .f. 
491 s .f 
491 sf. 
491 s .f. 
491 s .f 
491 s .f 
66 ,203 s.f. 
43,010 s.f. 
EXISTING SITE CANOPY SUBTOTAL 3,623 s.f. X 2 = 7,246 s.f 
EXISTING SITE CANOPY OVER PARKING LOT SUBTOTAL 1,437 s.f. 
TOTAL QUALIFYING TREE CANOPY AREA: 
TOTAL QUALIFYING TREE CANOPY AREA OVER PARKING LOT: 
1-1 
73.449 s.f. 
44,447 s.f. 
mm~~m~*~~~~~~~~~!j~~~~!~~ COVERED SOIL VOLUME 
~'f!l'=- ~~~;~~D 
PARKING TREE WITH COVERED SOIL DETAIL 
NOT TO SCALE 
SW HUNZIKER AND SW WALL ST. JOO NU~BER XX INDUSTRIAL 
SHEET 
T~gard OREGON 1 OF 1 
/ 
~ 
!REVISIONS: 
/ 
/ 
/ 
/ 
/ 
/ #~ /-/ 
~~~~-/ 
co~ / 
/' 
/ 
/ ARMSTRO NG MAPLE (TYP.) COVERED SOIL (TYP.) 
/ 
SCALE 1" - 20 FEET 
----
F==UJIII!. ~ l 
/ 
TAX LOT 201 
TAX MAP 2S 1 02AC 
TAX LOT 11 00 
TAX MAP 2S 1 02AC 
BUILDING 
BUILDING 
SITE TREE 
CANOPY PLAN 
/ 
BUILDING 
TAX LOT 700 
TAX MAP 2S 1 02AC 
APPROXIMATE 100-YEAR 
FLOOD PlAIN EL: 150.00 
PERCWSDATA 
' '· ' \ 
" 
TREE LEGEND 
SYWBOl Qll[S. BOTAHICAI. NAil[ COIIIION NAil[ CONDIOON SIZE SPACit«: 
& 2 ACER RIJBRUII 'ARIISTRONG' ARIIS1RONG RED IW'I.£ BleB 2" CAL IS S/«lWWI 9 CORNUS NtJTTAUJ PACiflC OOGWOOO BleB 2" CAL IS S/«lWWI 
NOTES: 
1. TREE PlANTING SPECIFICATIONS: REFER TO SUPPLEMENTAL ARBORIST REPORT. 
2. IMPROVE AREAS WITH TREE GROWTH UMITING SOILS; REFER TO SUPPLEMENTAL ARBORIST REPORT FOR SPECIFICATIONS. 
TREE CANOPY TABLE 
% CANOPY OVER ~ QUALIFYING SITE 
!BEU SPECIES OPEN SOIL VOLUME COVERED SOIL VOLUM E TOTAl SOIL VOLUME AYE MATURE CANOPY (!;TISFI PARKING LOT PARKING LOT CANOPY 
10000 P.cik Dog't'I'OOd 0\ef 1,000cf Ocf. 0~e"1 ,000c f 30' spread 707 
"" 
153 sf 707s{ 
10001 Pacik Dogwood O'oet' 1,000cf ,,, 0\ller t .OOOcf 30' &.ptelld 707 
"" 
174sf 707sf 
10002 Paciic Dogwood 0-..ert .OOOc:f. Oof o ... t .OOOcf 30' spread 707 
"" 
238 sf. 707s{ 
10003 Pacik Dogwood 0-.ert ,OOOcf Oc.f Cher 1.000 e f 30' sprelld 707 
"" 
173sf. 707sf. 
10004 Pacific Dogwood a_. 1,000cf Od 0\llll'l ,OOOcf 30' spread 707 
"" 
178 ro f 707 sf. 
10005 Pacik Dogwood Cher t .OOOc f Od 0'«<1 ,000cf 30' spread 707 
"" 
182 s f. 707sf. 
10006 Paciic Dogwood 0\ef 1,000cf Oof OWift ,OOOcf 30' spread 707 
"" 
181sf 707 sf. 
10007 Pacific Dogwood O..er 1,000cf 
"' 
O~erl , OOOcf 30' spread 707 ,.,. 183 sf. 707 sf. 
10008 Pacific Dogwood O..et 1,000cf "f o ... t .OOOcf 30' spread 707 
"" 
178sf. 707sf. 
10000 Armstrong Maple 48d 990 c f. 1,038c f 15' spread 177 Street Tree 0 177sf. 
10010 Arrnstroog M1ple 48' f 990 c f. 1.038cf 15" spread 177 Street Tree 0 177s.f. 
SITE CANOPY SUBTOTAL 6,717 sf 
CANOPY OVER PARKING LOT SUBT.QIM.. 1.1$20 sf. 
" \ 
EXISTING TREE CANOPY 
TREEII 10114. 10125 EXISTING SITE CANOPY SUBTOTAL 1,878 sf X2"' 3.752 s f. 
I 
I 
... 
l 
/ 
/ 
/ 
"'/ 
/ 
/ 
\ '· 
EDGE OF \ 
\ WATER '\ 
' \ ~. 
APPROX. LIMIT OF PARKING LOT CANOPY {TYP.) 
I 
TAX LOT 200 
TAX IAAP 25 I O"JN; 
\---+-~~~~~i+~T~;~Hc;!~N 
EXISTING TREE CANOPY OVER PARKING LOT 
TREE# 10114, 10125 
EXISTING SITE CANOPY OVER PARKIN G LOT SUBTOTAL 
TOTAL QUALIFYI NG TREE CANOPY AREA.: 
~ EXISTING CANOPY COVER TO REMAIN 
D QUALIFYING MATURE CANOPY COVER 
INDIVIDUAL TREE MATURE CANOPY OUTLINE 
~ EXISTING TREE CANOPY OUTLINE 
TOTAL SITE AREA: 24.864 S.F. 
TOTAL QUALIFYING MATURE TREE CANOPY AREA: 10,469 S.F. 
% CANOPY COVER: 42% 
MINIMUM % CANOPY COVER: 25% 
TOTAL QUAliFYING TREE CANOPY AREA. OV ER PARKING LOT: 
• 
OPEN SOIL VOLUME 
COVERED SOIL VOLUME 
PARKING LOT AREA: 6.940 S.F. 
TOTAL QUALIFYING MATURE TREE CANOPY AREA: 2.118 S.F. 
% CANOPY COVER: 31% 
MINIMUM % CANOPY COVER: J0-.4 
42•Ao IS GREATER THAN THE MINIMUM OF 25% TOTAL QUALIFYING MATURE CANOPY COVER FOR THE SITE. THEREFORE CITY 
REQUIREMENTS ARE MET. ADDITIONALLY. THERE IS 31% CANOPY COVER OVER THE PARKING LOT. EXCEEDING THE REQUIRED 
30% COVERAGE. 
REMOVAL, STORING. AND AMENDED SOILS FOR PlANTER AREAS: 
CONTRACTOR SHALL REMOVAL ALL DEBRIS FROM PLANTER AREAS AND EXCAVATE TO A DEPTH OF 36 INCHES. SLOPE SIDES OF 
EXCAVATIONS AT 1:1 SLOPE OR SHORE EDGES TO PREVENT UNDERMINING OF VEHICLE LOAD AREAS AN D TO PROVIDE A SLOPED 
PROFILE TRANSITION BETWEEN SOIL TYPES AND STRUCTURAL FILL. DISPOSE OF DEBRIS AND SUBSOIL. STOCKPILE EXCAVATED 
TOPSOIL IN APPROVED AREA OFF SITE. 
EXISTING AND IMPORTED TOPSOIL AMENDMENTS SHALL BE DETERMINED BY THE LANDSCAPE ARCHITECT AND APPROVED BY THE 
CITY ARBOR/ST. SotL MIXING SHALL BE DONE IN DESIGNATED AREAS OR IN THE SUPPLIERS YARD. MIX AMENDMENTS WITH TOPSOIL 
WHEN SOIL IS IN A FRIABLE CONDITION ONLY ( DAMP AND NOT MUDDY WITH ADEQUATE MOISTURE TO BREAK INTO CLOOS WHEN 
TURNED AND WILL NOT LEAVE A MUD STAIN ON THE HAND WHEN SQUEEZED) . CONTRACTOR TO PROVIDE CERTIFICATE OF CONTENT 
AND PERCENT OF SOIL MIXES WITH ALL AMENDED SOIL TO THE CITY PRIOR TO INSTALLATION. 
BLENDED SOIL PLACEMENT AND COMPACTION: 
SOIL SHALL BE FRIABLE WHEN PLACED AND COMPACTED. PLACE SOIL IN LAYERS OF NOT MORE THAN 12" IN DEPTH. PROVIDE 3 
PASSES WITH A 2- COMPACT PLATE VIBRATING COMPACTOR. COMPACT TO S0.85% MAXIMUM DRY DENSITY AS MEASURED BY THE 
PROCTOR TEST OR AS APPROVED FOR SPECIFIC BLENDED SOIL MIXES. 
/ 
(1\ COVERED SOIL DETAIL 
'C_) NOT TO SCALE 
ENCliEEJltiG . l'lANftl 8U'I'IEYI«l 
UCDISEDNIII,IA ... ~
KJ I!J!A!K !!),: XX I OCS!!?Ip R 
FOIE81RY I KAH SCAli' IS NOTID MAX'S BREW PUB PARKING 
LOT IMPROVEMENTS OffiCes Located In: KJ 13910 SW GALBREATH OR., SUITE 100 Sf(R.xJO, OR!:GON SHER.xJO. OR 971<10 ~ I!EllWOMl, OR!:GON 
PHONE: (503) 92!>-8799 VAHCO\JI'ER, WASHINGTON 
FAX: (503) 92!>-8969 ,_,.... l flRS1RY nw.oks-!!9.COin 12562 SW MAIN STREET TIGARD, OREGON 
City of 'T'igard Urban Forestry Code RcY isions I \'olumc II I 193 
OA 
498sf. 
10 469 a. f. 
21 18a.f. 
JOB NU~BER 
XX 
SHEET 
1 OF 1 
EXISTING )>· I BUILDING 
016 
II 017 
It~~ 
I 
APPROXIMATE PROPERTY LINE 
REVISIONS: 
[) 
/f/ 
BASEBALL/SPORTS 
RELD 
'\) ~  
ACCOLADE ELM (TYP 
APPROX. LIMIT OF PARKING 
LOT CANOPY (TYP.). 
SITE TREE 
CANOPY PLAN 
y 
TREE CANOPY TABLE 
TREE# SPECIES OPEN SOIL VOLUME COVERED SOIL VOLUME TOTAL SOIL VOLUME AVE. MATURE CANOPY % OF CANOPY OVER PARKING LOT AREA OVER PARKING LOT QUALIFYING SITE CANOPY 
019 
001 Red Maple (Acerrubrum) 
002 Red Maple (Acerrubrum) 
003 Accolade Elm (Ulmus Morton 
004 Accolade Elm (Ulmus Morton 
005 Red Maple (Acerrubrum) 
006 Accolade Elm (Ulmus Morton 
007 Red Maple (Acerrubrum) 
008 Red Maple (Acerrubrum) 
009 Accolade Elm (Ulmus Morton 
010 Accolade Elm (Ulmus Morton 
011 Red Maple (Acerrubrum) 
012 Red Maple (Acerrubrum) 
013 Red Maple (Acerrubrum) 
014 Accolade Elm (Ulmus Morton 
015 Accolade Elm (Ulmus Morton 
016 Accolade Elm (Ulmus Morton 
017 Accolade Elm (Ulmus Morton 
018 Accolade Elm (Ulmus Morton 
019 Acco lade Elm {Ulmus Morton 
vv~~~IL·~ A ( I ' \ I ! Ill . · 1 -
SCALE I" - 40 FEET 
---J Jllllt " ~ 
COVERED SOIL (TYP.) 
MATURE CANOPY COVER (TYP.) 
EXISTING TREE CANOPY (TYP.) 
O..er 1,000 c f. U C I. 0-.er 1,000 c f 40' spread (1 ,256 sf ) 
O..er 1,000 c.f Oc.f 0-.er 1,000 c f 40' spread {1 ,256 s.f.) 
0-.er 1,000 c.f 0 c .f. Owr1 ,000c.f 60' spread (2,826 s .f ) 
0-.er 1,000 c.f. 0 c .f. 0\er 1,000 c .f 60' spread (2 ,826 s .f.) 
0\er 1,000 c .f. 0 c .f 0-.er 1,000c .f. 40' spread (1 ,256 s.f.) 
0-.er 1,000 c .f. Oc.f 0-.er 1,000c.f. 60' spread (2,826 s.f.) 
0-.er 1,000 c .f. 0 c.f. O..e r 1,000c.f. 40' spread (1 ,256 s .f.) 
507 c.f. 537 c.f. 1,044 c. f. 40' spread (1 ,256 s .f.) 
O..er1 ,000c .f. 0 c.f 0\er 1,000 c f. 60' spread (2,826 s.f.) 
O..e r 1,000 c.f 0 c.f 0\er 1,000 c .f 60' spread (2,826 s.f) 
O..er 1,000 c.f. Oc.f O..e r 1,000 c .f. 40' spread (1 ,256 sf.) 
O..er 1,000 c.f Oc.f. O..er 1,000 cf. 40' spread (1 ,256 s.f.) 
O..er 1,000 cf 0 c.f. O..er 1,000c.f 40' spread (1 ,256 s.f.) 
O..er 1,000 c . f. 0 c f O..er 1,000c.f 60' spread (2,826 sf) 
O..er 1,000 c .f 0 c.f. O..er 1,000c.f. 60' spread (2,826 s .f.) 
O..er 1,000 c.f. 0 c.f. O..e r 1,000 c.f. 60' spread (2 ,826 s .f.) 
O..er 1,000 c . f. 0 cf. O..e r1 ,000 c.f. 60' spread (2 ,826 s .f.) 
O..er 1,000 c.f. 0 c .f. O..er 1,000c.f. 60' spread (2 ,826 s .f.) 
O..er 1,000 c .f 0 c. f 0-.er 1,000 c f 60' spread (2 ,826 s.f.) 
TREE LEGEND 
SYMBOL QTIES. BOTANICAL NAME COMMON NAME CONDITION 
~ 8 ACERRUBRUM REO MAPLE B&B 11 ULMUS 'MORTON' ACCOLADE ELM B&B 
SIZE 
2" CAL. 
T CAL. 
77% 964 s.f. 1,256 sf. 
28% 324 sf 1,256 s .f. 
66% 1,864 s .f. 2,826 s.f 
64% 1,799 s.f. 2 ,826 s .f. 
96% 1,203 s.f. 1,256 s .f. 
67% 1,943 s .f. 2 ,826 s .f. 
81% 1,015 s .f 1,256 s .f 
43% 537 s.f. 1,256 s.f. 
57% 1,605 s.f. 2 ,826 s .f. 
33% 936 s.f. 2 ,826 s .f 
75% 938 s .f 1,256 s.f. 
74% 932 s.f 1,256 s.f. 
28% 351 sf 1,256 s.f. 
Not Parking Lot Tree NA 2,826 s.f. 
Not Parking Lot Tree NA 2,826 s.f. 
Not Parking Lot Tree NA 2,826 s.f 
Not Parking Lot Tree NA 2,826 s.f. 
Not Parking lot Tree NA 2,826 s.f. 
Not Parking lot Tree NA 2,826 s.f. 
SITE CA NOPY SUBTOTAL : 41 ,134 s.f. 
EXISTING SITE CANOPY SUBTOTAL 5,936 sf. x 2 =11 ,872 s.f. 
TOTAL QUALIFYING TREE CANOPY AREA: 53.006 s.f. 
TOTAL QUALIFYING CANOPY OVER PARKING LOT : 14 411 s.f. 
SPACING 
AS SHOWN 
AS SHOWN 
• OPEN SOIL VOLUME 
COVERED SOIL VOlUME 
D QUALIFYING MATURE CANOPY COVER 
INDIVIDUAl TREE MATURE CANOPY OUTLINE 
~ EXISTING TREE CANOPY OUTLINE 
TOTAl SITE AREA: 206.039 S.F. 
TOTAL QUALIFYING MATURE TREE CANOPY AREA: 53,006 S.F. 
% CANOPY COVER: 26% 
MINIMUM % CANOPY COVER: 25% 
COVERED SOIL 
VOLUME 
PARKING LOT AREA: 33,568 S.F. 
TOTAL QUALIFYING MATURE TREE CANOPY AREA•: 14,648 S.F. 
% CANOPY COVER: 42% 
31EffErfE11~' 11~1ir:@jfE!(' v §ITEII!Mi7EIIEIFBIEJIDW COMPACTED 
r--llr--llr--llr--'rrr--'Tf=r. -Jir--••r--••r--Wl:r--llr--1 r--Jir--llr--IJr--••r--· · SUBGRADE 
MINIMUM % CANOPY COVER: 30% 
PARKING TREE WITH COVERED SOIL DETAIL 
NOT TO SCALE 
REMOVAL, STORING, AND AMENDED SOILS FOR PlANTER AREAS: 
26% IS GREATER THAN THE MINIMUM OF 25% TOTAl QUALIFYING 
MATURE CANOPY COVER FOR THE SITE, THEREFORE CITY 
REQUIREMENTS ARE MET. ADDITIONAllY, THERE IS 42% CANOPY 
COVER OVER THE PARKING LOT, EXCEEDING THE REQUIRED 30% 
COVERAGE. 
CONTRACTOR SHALL REMOVAL All DEBRIS FROM PlANTER AREAS AND EXCAVATE TO A DEPTH OF 36 1NCHES. SLOPE SIDES 
OF EXCAVATIONS AT 1;1 SLOPE OR SHORE EDGES TO PREVENT UNDERMINING OF VEHICLE LOAD AREAS AND TO PROVIDE A 
SLOPED PROFILE TRANSITION BETWEEN SotL TYPES AND STRUCTURAL FILL. DISPOSE OF DEBRIS AND SUBSOIL. STOCKPILE 
EXCAVATED TOPSOIL IN APPROVED AREA OFF SITE. 
EXISTING AND IMPORTED TOPSOIL AMENDMENTS SHALL BE DETERMINED BY THE LANDSCAPE ARCHITECT AND APPROVED BY 
THE CITY ARBORIST. Sotl MIXING SHALL BE DONE IN DESIGNATED AREAS OR IN THE SUPPLIERS YARD. MIX AMENDMENTS 
WITH TOPSOIL WHEN SOIL IS IN A FRIABLE CONDITION ONLY ( DAMP AND NOT MUDDY WITH ADEQUATE MOISTURE TO BREAK 
INTO CLODS WHEN TURNED AND WILL NOT LEAVE A MUD STAIN ON THE HAND WHEN SQUEEZED) . CONTRACTOR TO PROVIDE 
CERTIFICATE OF CONTENT AND PERCENT OF SOIL MIXES WITH ALL AMENDED SOIL TO THE CITY PRIOR TO INSTALLATION. 
BLENDED SOIL PLACEMENT AND COMPACTION: 
SOIL SHALL BE FRIABLE WHEN PLACED AND COMPACTED. PlACE SOIL IN LAYERS OF NOT MORE THAN 12" IN DEPTH. PROVlDE 
3 PASSES WITH A 2~ COMPACT PLATE VIBRATING COMPACTOR. COMPACT TO 8~% MAXIMUM DRY DENSITY AS MEASURED 
BY THE PROCTOR TEST OR AS APPROVED FOR SPECIFIC BLENDED SOIL MIXES. 
OC!pQ BY; KJ I DRAINC NO • XX I 
FORESTRY I KAH ,.,.,., ~ NOTID ENCliEEINl • f'I..AIHoiQ 8URYE'IIIIG 
IIDIS[ll~ ......... . BROADWAY ROSE INSTITUTIONAL 
OffiCes located In: KJ 
PREPARED FOR: 13910 SW GAI..BREATH DR, SUITE 100 SHER¥1000, OREGON 
SHERVIOOD, OR 9n<W A REDIIOND, OREGON 
P!f(lj[: (500) 925-8799 VANCQMR, WASHNGTON 
f111.: (503) 925-8969 DDE£Rt«; a: rCHSTRY www.ob-mcom OREGON 
5 
JOB NUNBER 
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PLANTED TREE WAllJRE OR1PUNE 
CANOPY AREA 
EXJSnNG SANITARY 
PROPOSED &ANITARY 
EXJSnNG WATER 
PROPOSED WATER 
PROPOSED WATER IIETER 
EXJSnNG STORW 
PROPOSED STORW 
PROPOSED IRRIGAWN WAJNUNE 
CJ 
-
TREE CANOPY PLAN 
TREE LEGEND 
SYIIBDL OnE& BOTANICAl NAIIE COIIWON NAWE CONDHlON 9ZE SPACING 
~US P£NNSYLVANCA GRHN ASH B&£1 'l CAL 30' D.C. 
CORNUS KOUSA KOUSA DOCIIOOD 8&8 2" CAL AS SHOWN 
PYRUS ColllERYANA CAllERY PEAR 8&8 'l CAL AS SHOWN 
NOTE: 
1. PLANTER STRIP AREAS AlONG OUAJCtiG ASPEN AVENUE AND TANNERY STREET ARE AREAS Of POTENnA! S(!L COWPACnctl, UllnNC TREE GROWTH. If S(!L 
CCioiPACnON OCOJRS, BACKHOE 1\JRNING SHOULD BE USED TO LOOSEN S(!L 
2. BACKHOE 1\JRNINC: REWOVE ANY LAYERS Of C000 TOf'S(!L SPREAD 3" -~· Of ORGANICS (HICH-UCN!-1 Cot.IPOST) OR ESCS (EXPANDED SHAlE/CAlCINE 
CLAY) AIIENDWENT OVER THE AREA. PRIOR TO 1\JRNING THE S(!L WAJNTAJNtiG A SAFE ~STANCE FROW PA>ING, SIDEWAlKS. AND STRUCllJRES. USE BACKHOE 
TO 1\JRN SOL TO 36" DEPTH. BREAJC 500. INTO LARGE PEDS AND LOOSElY INODRPORATE THE S(!L AWENDWENT. WAINTAJN A SLOPE Of OOWPACTED S(!L AT 
THE EDGE Of PA>INC SO AS NOT TO Ut«RRIINE THE PA>ING SUB-BASE. HAND 1\JRNtiG WAY BE ~CE&SARY AlONG M EDGES Of PA>ING AND AT WAILs. 
00 NOT nLL TO A DEPTH GREATER THAN THE BOTIOW Of roonNG. AflER 1\JRNING, RE-SPREAD TOf'S(!L AND ADD 3"-5" Of YARD WASTE OOGANC 
AIIENOWENT OVER THE SURF ACE AND UCHTL Y ru TO BREAJC THE SOL INTO TEXTURE SUITABI£ TO nNE GRADE. 
TREE CANOPY TABLE 
TREE I SPECIES OPEN SOIL VOLUME COVERED SOIL VOLUME TOTAL SOIL VOLUME AVE. MATURE CANOPY jFT/SF) QUALIFYING SITE CANOPY 
10000 Green Ash Q.,.,rl ,OOOc.f Ocf 01ef l,OOOc f. 40' spread 1,256 1,256 sf 
10001 Green Ash o...,r1 ,000c.f Ocf Oo,er 1,000c.f 40' spread 1,256 1,256 s.f. 
10002 Callery Pear 0-.er 1,000c f. Od O..er 1,000cf. 25' spread 491 491sf. 
10003 Kousa Dogwood 0-.er 1,000c.f 45c.f. 0-.er 1,000c.f. 25' spread 491 491sf 
10004 Callery Pear O~oer 1,000cf Ocf 0-.er 1,000c.f 25' spread 491 491sf. 
10005 Kousa Dogwood 0-.er 1,000c.f. Oc .f 0-.er 1,000cf 25' spread 491 491sf. 
10006 Callery Pear Owrt ,OOOc.f Oo f 0-.erl ,OOOc.f 25' spread 49\ 491s.f. 
\0007 Kousa Dogwood 0-.er 1,000c.f. 45cf. 0-.er 1,000c.f. 25' spread 49\ 491sf 
\0008 Callery Pear Owrt ,OOOcf Oc.f. 0-.er 1,000cf 25' sprsad 491 491$.f. 
10009 Kousa Dogwood o.,.,, t ,OOOc.f Od 0-.er 1,000c.f 25' spread 49\ 491s.f. 
10010 Calle~)' Peer Q.,.,r 1,000c.f Ocf Ole!" 1,000cf. 25' spread 49\ 491sf 
10011 Kousa Dogwood 0\oef 1,000cf 45cf 0-.er 1,000cf 25' sprNd 49\ 491sf_ 
10012 Callery Pear Owr 1,000c.f. Ocf. O..er 1,000cf 25' spread 49\ 491sf. 
10013 Kousa Dogwood O..er 1,000cf 
'" 
0\oef 1,000cf 25' spread 49\ 491sf 
10014 Callery Pear O..er 1,000c f Oc.f O..er 1,000 c.f 25' spread 49\ 491 s.f. 
10015 Kousa Dogwood O..er 1,000cf_ 45cf. 01oef 1,000c.f 25' spread 49\ 491 sf. 
10016 Catfery Pear O..er 1,000cf 
'" 
0\oef 1,000c f. 25' spread 49\ 491 s f_ 
1,620 sf 
TOTAl QUALIFYING SITE TREE CANOPY AREA 10 368 &.f. 
PREPARED FOR: 
ENQtEERtiQ ' f't..AioNIQ 9URVEYH3 FOfES1RY IIQC!fP uy; KJ I!JRA•tli NO · XX I 
,'Mol BY: KAH SCALI: AS NOTED 
UCDISED ~OR. WUNC ~
OffiCes located ~ : 
~~~~~~!\;OR , SUITE 100 J ~~::.\::: 
PHONE: (503) 925-B799 VANCOUVER, WASHNGTON 
FAX: {503) 925-8969 EHGNI.RNC 1:: fa!ESTRY www.oks-eng,com 
0£CKED BY: KJ 
SCALE ! " = 20 FEET 
---~ ~~ ~ 
D QUALIFYING MATURE CANOPY COVER 
INDIVIDUAL TREE MATURE CANOPY OUTLINE 
Bl OPEN SOIL VOLUME 
COVERED SOIL VOLUME 
TOTAL SITE AREA: 29.51 1 S.F. 
TOTAL QUALIFYING MATURE TREE CANOPY AREA: 10,368 S.F. 
% CANOPY COVER: 35% 
MINIMUM % CANOPY COVER: 33% 
35% IS GREATER THAN THE MINIMUM OF 33% TOTAL QUALIFYING 
MATURE CANOPY COVER FOR THE SITE. THEREFORE CITY 
REQUIREMENTS ARE MET. 
SEQUOIA LANDING 
OREGON 
DA 
I, JOHN ARBORIST, A ffiST THAT 
THIS TREE CANOPY SITE PLAN 
~EETS ALL Of THE 
REQUIRE~ENTS IN SECTION 10, 
PART 2, Of THE CITY Of TIGARD 
URBAN FORESTRY ~ANUAL 
JOHN ARBORIST, CERTIFIED ARBORIST 
PNN-0000 
I 
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TAX LOT 200 
I 
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SYIIBOL 
TREE LEGEND 
onES. BOTN«:..I. NAIIE COIIWON NAME CO!fXTION SIZE SPN:ING 
TAX LOT 4100 TAX LOT 4200 
TAXMAP 25 I lOBO T AXMAP 25 I I OBD 
SITE TREE 
CANOPY PLAN 
' 
TAX LOT 5000 
TAX MAP 25 I I 0130 
10 
9 
8 
7 
TAX LOT 1300 
TAXMAP 2S I IOBC 
I 
l 
"I 
TAX LOT 1800 
TAXMAP 25 I IOBC 
TAX LOT 1700 
TAX MAP 2S I I OBC 
SCAlE I" = 40 FEET 
----J Jllllt " ~ 
016 
Q9 
NOTES: 
N::ER R\JBR1N RED WAPI.£ 
Z[LJ(()VA SERRATA Z[LJ(OVA 
1. TREE PlANTING SPECIFICATIONS: REFER TO SUPPLEMENTAL ARBORIST REPORT. 
B&B 2" CAL /oS SHOWM 
B&B 2" CAL /oS SHOWM 
2. IMPROVE AREAS WITH TREE GROWTH LIMITING SOILS; REFER TO SUPPLEMENTAL ARBOR 1ST REPORT FOR SPECIFICATIONS. 
3. PLANTER STRIPS AND RIGHT OF WAYS ARE AREAS OF POTENTIAL SOIL COMPACTION, LIMITING TREE GROWTH. IF SOIL COMPACTION OCCURS, BACKHOE TURNING 
SHOULD BE USED TO LOOSEN SOIL. 
4. BACKHOE TURNING: REMOVE ANY LAYERS OF GOOD TOPSOIL. SPREAD 3•-4• OF ORGANICS (HIGH-LIGNIN COMPOST) OR ESCS (EXPANDED SHALE/CAlCINE CLAY) 
AMENDMENT OVER THE AREA, PRIOR TO TURNING THE SOIL MAINTAINING A SAFE DISTANCE FROM PAVING, SIDEWALKS, AND STRUCTURES. USE BACKHOE TO TURN 
SOIL TO 35· DEPTH. BREAK SOIL INTO LARGE PEDS AND LOOSELY INCORPORATE THE SOIL AMENDMENT. MAINTAIN A SLOPE OF COMPACTED SOIL AT THE EDGE OF 
PAVING SO AS NOT TO UNDERMINE THE PAVING SUB-BASE. HAND TURNING MAY BE NECESSARY ALONG THE EDGES OF PAVING AND AT WALLS. 00 NOT TILL TO A 
DEPTH GREATER THAN THE BOTIOM OF FOOTING. AFTER TURNING. RE..SPREAO TOPSOIL AND ADO 3"-5" OF YARD WASTE ORGANIC AMENDMENT OVER THE SURFACE 
AND LIGHTLY TILL TO BREAK THE SOIL INTO TEXTURE SUITABLE TO FINE GRADE. 
TREE CANOPY TABLE 
TREE I 
10000 
10001 
10002 
10003 
1000< 
10005 
10006 
10007 
10008 
10009 
10010 
10011 
10012 
10013 
10014 
10015 
10016 
10017 
10018 
10019 
10020 
10021 
10022 
10023 
10024 
SPEOES 
Zelko.,. 
Zelko.,. 
l.ell(o.,. 
z.o•~ 
z.•o.,. 
Red Maple 
Red M.P., 
Red M-Pe 
Red M.Pe 
Red Maple 
OPEN SOIL VOLUME COVERED SOIL VOLUME TOTAL SOIL VOLUME AVE. MATURE CANOPY (fTJSF l 
QUALIFYI NG SITE 
CANOPY 
11il63 s f 
11il63 s f 
-~ Zelko.,. 
Zelko.,. 
Red Maple 
Red Maple 
Red Maple 
Red Maple 
Red Maple 
Red Maple 
Red Maple 
Red Maple 
Red Maple 
Red Maple 
Red Maple 
Zelko... 
EXISTING TREE CANOPY 
TREEt 10158. 10150. 10160, 10164 
0-.ef 1,VVVC:I 
0-.er 1,000 c: f 
0-.er 1,000 c: f 
0-.er 1,000 c: f 
0\olllr 1,000 c f 
0-.er 1,000 c: f 
0-.ert.OOOc:f 
0-.er 1,000 c: f 
0-.ert .OOOc: f 
0-.er 1,000 cf 
O-.er1 ,000cf 
o- t ,OOOcf 
0-.er 1,000c: f 
0-.er t ,OOOc f 
0-.er t ,OOOcf 
0-.er 1,000cf 
0-.er 1,000 c: f 
O...r 1,000 c f. 
0-.er t .OOOc.f 
0-.er 1,000c:f. 
0-.er 1,000 c.f 
Owr 1,000c.f. 
Owr t.OOOcf 
Owr t .OOOc.f 
0-.er 1,000 c f 
D QUALIFYING MATURE CANOPY COVER 
QUALIFYING EXISTING CANOPY COVER 
Ocf. 
'" Oc:f.
Oof 
Ocf. 
Oc:f. 
'" Od
'" 
'" Oc f.
'" Oof 
Ocf. 
Oof 
Ocf. 
oc.f. 
Ocf. 
Ocf. 
Oc .f 
Ocf. 
Ocf. 
Oc.f. 
Ocf. 
Ocf. 
INDIVIDUAL TREE MATURE CANOPY OUTLINE 
~ EXISTING TREE CANOPY OUTLINE 
TOTAL SITE AREA: 85,072 S.F. 
TOTAL QUALIFYING MATURE TREE CANOPY AREA: 38,205 S.F. 
%CANOPY COVER: 44o/o 
MINIMUM % CANOPY COVER: 40% 
44% IS GREATER THAN THE MINIMUM OF 40% TOTAL QUALIFYING 
MATURE CANOPY COVER FOR THE SITE, THEREFORE CITY 
REQUIREMENTS ARE MET. 
0Y~M1 .000c f 
0Y~M1 ,000cf 
0Y~M1 ,000c f 
0Y~M1 ,000c f 
0YI!If1 .000c: f 
0YI!If1 ,000c: f 
0~«1 ,000c: f 
0Y~M1 .000cf 
0Y~M1 ,000cf 
0Y~M1 ,000cf 
o--t.OOOcf 
0~«1 ,000cf 
0Y~M1 ,000cf 
o--1 ,000cf 
<her 1,000 c f 
a-- 1,000 c f 
0~«1 ,000cf 
0~«1.000cf 
0~«1 ,000c:f 
O~er 1,000cf 
0Y~M1 ,000cf 
0Y~M1 ,000cf 
OY~Mt,OOOcf 
0Y~M1,000cf 
0YI!If1 ,000c: f 
50' spread 
50' spread 
50' spread 
50' spread 
50' spread 
35' spread 
35'spread 
35' spread 
35' spread 
35' spread 
50' spread 
50' spread 
50' spread 
35' spreed 
35'spreed 
35'spread 
35' spreed 
35' spread 
35' spread 
35'spread 
35' spread 
35'spread 
35'sprMCI 
35' spread 
50' spread 
1,963 
1,963 
1,963 
1,963 
1,963 
962 
962 
062 
962 
962 
1,963 
1,963 
1,.., 
962 
962 
962 
962 
962 
962 
962 
962 
962 
962 
962 
1,963 
1983 sf 
11il63sf 
11il63sf 
962 sf 
962 sf 
962 s f 
962 sf 
962 s f 
tij63sf 
1963 sf 
tlil63sf 
962' f 
962 sf 
962 s f 
962 sf 
962 sf 
9e2 sf 
962 sf 
962 sf 
962. f 
962. f 
962. f 
11il63sf 
SITE CANOPY SUBTOTAL 33,05Sil s f 
EXISTING SITE CANOPY SUBTOTAL 2.573 sf X2" 5,14e sf 
TOTAL QUALIFYING SITE TREE CANOPY 38 205 d . 
l.EOEN) 
EXIS11NG SANITARY 
PROPOSED SANITARY 
EXIS11NG WATER 
PROPOSED WATER 
PROPOSED WATER VALVE 
EX1S11NG STORII 
PROPOSED STORII 
EXIS11NG TWI'!«lNE 
EXIS11NG O'IER 100 WIRE 
EXIS11NG GAS 
KJ I!J!A!!S NO.: XX I FOfES'TRY liMP BT: KAH m AS NOTED 
BULL MOUNTAIN VIEW ESTATES 
ENC»EEft«l • ~ 8U'IVEYN) 
UCENSlll~OR.WA•AK OffiCes located In: KJ 
OREGON TIGARD 
13910 5W GAlBREATH DR, SU1TE 100 SIERWOOD. !JlEOON 
SHERWOOD. OR 971~ ~ REDWOND, !JlEOON 
1'\iONE: (503) 925-8799 VANCOUVER. WASHINGTON 
FAX: (503) 925-8969 DfCII£IRINC • rtm1RY www.oks-on~com 
TAX LOT 1400 WASHINGTON COONTY TAX WAP NUMBER 2S-1-100C 
City ofTiganJ Urban Forestry Code Rc,·isiom I \'olumc II I 199 
JOB NU~BER 
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!$! I I z ~ I I I r EXISTING RETAINING WALL 
~ ; 
1 ~ ~~ . ~~~~~~~~~~~~~~DZ~~~~~~~~~77~ : I I • I 
TREE CANOPY TABLE 
EXISTING TREE CANOPY 
lREO SPECES SPREAD ~ETER IN FEE!} AREA ISFI 
10001 Douglas Fir 34 
""' 10008 Douglas F.r 40 1257 
L..EQEN) 
10009 Douglas Fir 34 
""' 10100 Dougla:; Fir 
"' 
1018 EJIISTN: SAN!TARY 
10101 Douglas Fir 
"' 
1018 
10102 Douglas Fir 34 
""' 10103 Douglas Fir 34 
""' 
Pl«lPOSED SANITARY 
10104 Douglas F1r 34 
""' 10105 Douglas Fir 35 755 EliiSTINC WAT£R 
10107 a.eny 35 755 
10106 a.eny 21 346 
10111 Rodwood 14 154 PROPOSED WATER 
10121 a.eny 21 346 
10122 Douglas Fir 25 491 PROPOSED WAT£R VAl~ 
10123 Oougi11S Fir 
"' 
1018 
10124 Douglas Fir 36 1018 
10125 Douglas Fir 31 755 EXISTING SfORij 
10126 Douglas Fir 25 491 
I 
I 
I 
_, v. (PRIVATE STRfETI 
------- --------------~ 
10127 Douglas Fir 2ll ,,, PROPOSED STORM ---------
I ! ~Jfi ' ! = ~ ,-.~ t' ~ 
, t tdf-ii fu • "tR ·+· 1 ~ f I \\··0®\ ~, 
~f- ..  
- T -~ t. 
, I 
+ (•4 
I ' 
I 
I 
I 
' 
I 
DECK 
---------+ ------------------
lo' Ill -
EXISTING HOME 
15000 SW 141ST 
' II 
fl 
l:r 
SERVICEBERRY 
STREET TREE 
1-----
1 "" 
I " I '\ 
'\ 
I 1A '\ 
I " : 
I __ BUILDING ENVELOPE__] 
I I 
: \ ____ J 
3A 
I 
I 
I 
I 
I 
"'\.__ _______ _j 
,-- ------, 
I I 
I I 
I 2A I 
I I 
I .~ I 
I 
10129 Douglas Fir 25 491 
10130 Douglas Fir 25 491 
10131 Douglas Fir 40 1257 EJIISTING TEIIPHONE 
10132 Douglas F1r 32 804 
10133 Douglas Fir 32 804 
10134 Douglas Fir 40 1257 ElllSTING POWER 
10135 Douglas Fir 40 1257 
1013e Douglas Fir 40 1257 
10137 Douglas Fir 32 804 
10138 Oouglu Fir 40 1257 
10139 Douglas Fir 32 
"" 
EXISTING SITE CANOPY TOT AI... 2s.1oe x2 = so.212 s r 
STREET TREE CANOPY 
~ 
10000 
10001 
~ 
Ser.iceberry 
Ser.icebeny 
OPEN SOIL VOLUME COVERED SOIL VOLUME TOTAl SOIL VOLUME AVE. MATURE CANOPY IFTISFl QUALIFYING SITE CANOPY 
1nsf O\oer1 ,1.AJUCT 
0\oer 1,000cf 
0<1 
0<1 
D 
~ 
QUALIFYING MATURE CANOPY COVER 
QUALIFYING EXISTING MATURE CANOPY COVER 
INDIVIDUAL TREE MATURE CANOPY OUTLINE 
~ EXISTING TREE CANOPY OUTLINE 
SCALE I" = 20 FEET 
---
TOTAL SITE AREA: 23,336 S.F. 
TOTAL QUALIFYING MATURE TREE CANOPY AREA: 50,566 S.F. 
%CANOPY COVER: 217% 
MINIMUM % CANOPY COVER: 40% 
211% IS GREATER THAN THE MINIMUM OF 40% TOTAL QUALIFYING 
MATURE CANOPY COVER FOR THE SITE, THEREFORE CITY 
REQUIREMENTS ARE MET. 
k Jllll!, ~ ~ 
0-.er 1,000 c f 
0-.er 1,000 c f. 
1s· spreac~ 1n 
1S' spread 1n 
TOTAL STREET TREE QUALIFYING CANOPY 
TOTAL SITE TREE QUALIFYI NG CANOPY 
S1llEET TREES 
SY\IOOL arB. BOTANICAl ~E 
1nst 
354 a.f. 
50 586 d . 
Q) AIIELINCHIER X GRANIJiflORA 
SITE TREE 
CANOPY PLAN 
ENOitEEFtNQ • f'!..Aif>N3 IUl'IEYI«l ~ lljlSI!?1ED B't AS NOTED KJ II!!"* NO; XX I •n• KAH SCALI: 
PREPARED FOR: 
KJ MASTER'S PARTITION OffiCes located In: 13910 SW GALBREATH OR .• SUITE 100 SI£Rll000. OREGON 
SHERliOOO, OR 97140 ~ REDIMJNO, OREGON 
COIIIIOH IWIE 
SE~ 
UC£NSID~OR.IUN<
PHONE: (503) 92~8799 VANCOOI'ER. WASKNGTON 
F A.'J;, {503) 925-8969 D«HHRRNC i rtR:SJn' www.oks-..-.a.com TIGARD OREGON 
City of Tigard Urban I 'ores try Code Rc,·isions I Volume 11 I 201 
caromoH SIZE 
B&B 2" CAL 
SPACING 
AS SHOWN 
JOB NU~BER 
XX 
SHEET 
1 OF 1 
"• 
P: (503) 925-8799 F : (503) 925-8969 
December 8, 2011 
Mr. John Floyd, Associate Planner 
Mr. Todd Prager, Associate Planner/ Arborist 
City of Tigard 
13125 SW Hall Blvd. 
Tigard, OR 97223 
E-Mail: Johnfl@tigard-or.gov 
E-Mail: Todd@tigard-or.gov 
ENGINEERING & FORESTRY 
Re: General Case Study Memo for "Peer Review" of the Urban Forestry Plans and Follow Up Reports 
for Six Development Sites 
Mr. Floyd and Mr. Prager 
Attached is our Case Study Memo for the following six sites: 
1. Bull Mountain View Estates (a 14lot residential subdivision-AKS #1283) 
2. Sequoia Landing (a 16lot 4 building 4-plex residential subdivision-AKS #1443) 
3. Master' s Partition (a 3 parcel residential partition-AKS #1376) 
4. Broadway Rose Site Development (commercial site-AKS #1872) 
5. 12565 SW Main Street (Max' s Brew Pub) Parking Lot Improvements (AKS #2049) 
6. SW Hunziker & SW Wall St. Industrial Site (commercial site designed by VLMK Engineers) 
The Case Study Report as outlined in the accepted proposal of9/22111 had a total of 11 man-hours budgeted and 
the scope of work was defined as: 
Case Study Report: 
AKS will then put together a Case Study Report summarizing our findings 
from implementing the draft code on the six sites. This report will cover items 
we liked about the code , items in the code we found difficult or expensive to 
implement, and any other key issues. 
At our meeting of 1 0/20111 we discussed providing a much more in depth Case Study Report for which a proposal 
was provided on 10/24/11 , however the City decided not to go with that scope and instead chose the much smaller 
9/22111 scope. 
City of Tigard Urban Forestry Code Rc,·isions I Volume II I 203 
General Case Study Memo From the "Peer Review" of the Urban Forestry Code for 6 Sites 
The case study is to be a general summary of the order of magnitude differences between the existing and proposed 
codes. 
Very Truly Yours, 
AKS Engineering & Forestly, LLC 
Keith Jehnke, PE, PLS, Principal; 
asa:J 
AM E RI C A N SO C IETY o f 
C O N S U LTI NG All.llORIS T S 
KEITH JEHNKE 
CERTIFIED 
--
1 ( ' -E!F'"~~ r · ~ 
- - .. 
- --
- -\ -- ~=~ 
ARBORIST 
CERTIFICATE NUMBER PN- 1905 
EX PI RATION DATE 6/30/20 13 
Certified Arborist #PN-1908, Certified Tree Risk Assessor #192 
Member, American Society of Consulting Arborists 
City of Tigard Urban l'orc,try Code Rc,·ision' I \ 'olumc II I 204 
Page 2 
General Case Study Memo From the "Peer Review" of the Urban Forestry Code for 6 Sites 
Case Study Report 
The purpose of this case study report is to evaluate the current tree code versus the proposed tree code as they 
apply to the 6 Case Study Sites per our professional opinion. Items to be compared include: 
• Flexibility 
• Construction Costs 
• Effect on Consultant Fees/Design Costs 
• Potential Infrastructure savings (sidewalks/curb/etc.) 
• Changes in design if projects were started from scratch 
• Theoretical difference between an "un-treed" lot and a heavily treed lot 
• Potential unintended design consequences 
This report will also contain summaries of: 
• Items AKS liked about the code 
• Items in the code AKS found difficult or expensive to implement 
• Technical comments on each of the six sites. 
• AKS recommended additions/clarifications to the code 
FLEXIBILITY: 
The proposed code allows increased flexibility in meeting the higher canopy and soil volume standards over the 
exhisting code. The ability to use covered soil areas to meet soil volume requirements allows the landowner to 
maximize usable spaces while meeting environmental and aesthetic objectives. Additionally, by taking a 
broader view of tree requirements through the minimum canopy cover percentage requirements, the City allows 
the landowner to work with the existing conditions and constraints of the site rather than trying to force design 
requirements that might not fit the site. In short, the proposed code gives options to the landowner and 
encourages a higher design standard. 
CONSTRUCTION COSTS: 
Given the cutting edge and unprecedented nature of the proposed code, the exact impacts to construction costs 
are difficult to predict in the short tem1. However, the proposed code is likely to increase site costs in these 
areas: 
• Increased soils cost for contractors. Covered soil mixtures costs will vary based on their compostition 
and availability, but will be more than than traditional organic soil mixtures used in many planting areas 
today. 
• Increased labor costs due to protecting soil and keeping structural soils at optimum moisture levels for 
placement. 
• Increased labor costs associated with higher tree protection rates due to incentives to keep existing trees. 
Page 3 
City o f Tigard Urban Forestry Code ReYisions I Volume II I 205 
General Case Study Memo From the "Peer Review" of the Urban Forestry Code for 6 Sites 
In doing these peer reviews, tree and vegetation cost increases are likely to be negligible. In most cases the 
proposed canopy requirements were met by fulfilling the street tree requirements and/or selecting trees with 
larger canopy areas. By using trees with larger canopy areas in parking lots, we were generally able to meet the 
increased canopy requirements without adding significantly more trees than were previously required under the 
old code. 
Industrial and infill projects proved the most challenging in meeting the increased canopy requirement due to 
having a higher ratio of paved area to vegetated area. These types of projects are likely to see a slight increase 
in vegetation costs under the new code necessitated by increased canopy coverage minimums. 
EFFECT ON CONSULT ANT FEES/DESIGN COSTS: 
Higher consultant fees and design costs are likely under the proposed code. These increases could be a 
combination of factors , including: 
• Initial increase in fees as developers and consultants adjust to working with the ' un-known' factor of 
the new standards. 
• Meeting new submittal standards requires more calculated information, construction details and 
oversight, increased number of sheets, and a higher degree of interdisciplinary coordination between 
architects, arborists, civil engineers, and landscape architects, thus increasing the level of effort and 
man hours needed to complete a project. 
These extra costs may be small to moderate, depending on the size of the site, existing conditions, desire of the 
client to implement 'creative ' solutions, size and ability of the design fim1 to handle multiple disciplines in 
house, etc. Industrial sites which require large areas of parking and hardscape and sites with ' tight ' conditions 
(such as built-up urban areas, small lots, remodels or renovations, etc.) will be more expensive to design and 
implement than open sites. 
POTENTIAL INFRASTRUCTURE SAVINGS: 
The proposed code requires 1 ,000 cubic feet of available soil for each tree. This soil is to be a minimum of 3 
feet deep, tilled, and of adequate composition. This works out to the equivalent minimum area of 18.26 feet 
wide by 18.26 feet long by 3 feet deep. When each tree is provided with the rooting area that it needs to thrive, 
it will reduce damage to adjacent public infrastructure such as sidewalk and curb because the roots have 
adequate room to grow. 
Using "covered soil" to connect open soil areas or to provide most of the required rooting volume allows a tree 
to be planted close to a curb or sidewalk and still allow the roots to grow without damaging the sidewalk or 
curb. 
Trees with adequate rooting area will thrive. Trees that are thriving are less likely to become diseased and are 
much more likely to recover from physical damage as well. When trees are thriving they grow faster and more 
quickly beautify their surroundings, purify the air, act as sound barriers, manufacture oxygen, and provide 
cooling shade in summer. In the 11 year old commercial building where AKS has their office there are site 
trees some of which were planted with very little rooting volume and some in central areas where there is more 
Page 4 
City of Tigard Urban Fo restry Code ReY i>ion> I \ 'olumc II I 206 
General Case Study Memo From the "Peer Review" of the Urban Forestry Code for 6 Sites 
area for the roots. The trees growing in the larger area have had 100% survival and are about 2.5 times the 
diameter of those trees in the smaller rooting sites. The mortality rate for the trees in the smaller planter areas 
was also about 33%. The proposed code will result in healthier, larger trees in less time and with less mortality. 
CHANGES IN DESIGN IF PROJECTS WERE STARTED FROM SCRATCH: 
The proposed code places a higher value on vegetation and tree canopy which will likely have impacts in the 
site layout and design process. Increased parking island and planter size and less overall hardscape are probable 
outcomes. Site layout may also be more responsive to existing trees on site with the objective to preserve them 
for double tree canopy credit. 
DIFFERENCE BETWEEN A TREED AND UN-TREED LOT: 
Theoretically, under the proposed code, a heavily treed lot will be more desirable to developers due to its 
increased potential for double tree credits. This potential impact is higher in undeveloped areas where a 
substantial number of trees are more likely to occur than in urban infill projects. Overall, benefits ofhaving a 
heavily treed lot versus an 'un-treed' lot are minimal in urban areas or on small lots. 
• TREED: The treed lot gives the option of preserving trees and eliminating the cost of site trees, but also 
presents challenges during and after construction. The more trees on the site the better the odds that 
some of these trees may be in logical areas allowing their preservation and eliminating the need to plant 
additional site trees. Preserved trees add climate control, postitive environmental impacts, and add a 
sense of maturity to the landscape, however they can also pose a danger to buildings, people, and 
property if not properly preserved. For instance, if the lot is densely stocked with conifer trees, then 
these trees will have a large height to diameter ratio and a corresponding higher risk ofwindthrow, 
making the tree more hazardous to preserve due to the windthrow risk. 
• UN-TREED: The un-treed site will require that the entire site's canopy requirement will have to be 
provided by street trees and site trees resulting in an additional cost to the landowner. Young trees, 
while having a better chance of survial than a mature tree on a disturbed site, also take longer to have the 
same aesthetic and environmental impact of the mature tree. 
POTENTIAL UNINTENDED DESIGN CONSEQUENCES: 
Although our review was limited to six site studies, we identifed the following potential unintended design 
consequences: 
• The proposed code favors deciduous trees, which have a larger mature canopy area than conifers, 
allowing the landowner to plant fewer trees to meet minimum canopy coverage. This may have a 
negative overall aesthetic effect if evergreen trees, which add year around interest and are important 
for screening, are excluded in favor of deciduous trees. 
• Since mature tree canopy is calculated by the approved tree list, variety of plants is 
limited. Developers will naturally plant trees with the largest canopy areas to minimize the number 
Page 5 
City of Tigard Urban Forestry Code Rc,·isions I Volume II I 207 
General Case Study Memo From the "Peer Review" of the Urban Forestry Code for 6 Sites 
of trees they are required to plant. This may create a monoculture of sorts, which can have negative 
environmental and aesthetic impacts. 
• · Emphasis on getting double canopy credit for existing trees may encourage saving questionable trees 
(or trees that will be negatively affected in the long term by construction activities) . 
• Landowners may "extend" their parking lot to reach an existing tree in order to utilize its existing 
canopy area in the parking lot canopy calculations. 
ITEMS AKS LIKED ABOUT THE CODE: 
Results Based Code: The proposed code focuses on what the parcel will look like in the future, not what it 
looks like in the present. That is, the code wants each parcel within a certain zone to meet certain minimum 
standards for the existing/future area of tree canopy. Many municipal tree codes focus on minimizing the 
removal of trees-thus "punishing" those owners that have an abundance of trees on their land prior to 
development while at the same time rewarding those landowners that have few or no trees on their land. The 
proposed code will encourage landowners to have trees on their parcels. 
Flexibility: As mentioned previously, the proposed code gives the landowner the ability to choose between 
leaving Jess open soil and more parking places/hardscape at the cost of higher planting costs (due to covered 
soil) or more open soil and less parking places/hardscape with the bonus oflower planting costs because 
covered soil is no longer required. This allows us to work creatively with our clients to meet their needs while 
also building a better site. 
Increased Chance of Tree Survival : The stricter soil requirements of the proposed code increase the chances of 
tree survival and ability to thrive. Long term, this will decrease maintenance and replacement costs typically 
associated with urban trees. From a personal standpoint, as a service provider, it is always gratifying to see our 
projects doing well and to see satisfied clients happy with the end result. 
ITEMS IN THE CODE AKS FOUND DIFFICULT OR EXPENSIVE TO IMPLEMENT: 
In general , most of the new code, with the clarifying details and example plans, was straight forward and easy to 
implement with a computer aided drafting program such as AutoCAD. 
• One area that seemed to be redundant was the necessity to calculate percent of canopy over parking lot 
for each individual tree. This process seemed time consuming, especially on larger sites with many 
parking lot trees, without adding information vital to showing how the site plan meets the minimum 
standards. 
• Since we were working with a relatively fixed site layout, any necessary changes were in response to 
meeting direct needs related to minimum canopy and soil volumes. However, in the initial stages of a 
' design from scratch' situation where building and hardscape layouts are not yet fixed, the process of 
calculating and recalculating soil volumes in the early stages could be time consuming. 
• The method for calculating existing tree canopy was not clear to us in the beginning. We recommend 
that the formula for calculating existing canopy be added to the code and it should be clarified if this 
calculation accounts for future growth like the planted tree list does. 
Page 6 
CitY of TigarJ Urban l'orc,try CoJc Re,·i>ion' I \'olumc II I 2118 
General Case Study Memo From the "Peer Review" of the Urban Forestry Code for 6 Sites 
• In some of the residential sites, we found that we had to adjust the street trees to meet minimum lot 
canopy at the sacrifice of aesthetics (such as overall symmetry, ' fairness ' oftree placement, etc.) and on-
site conditions (such as placing trees closer to access points and existing tree canopy overhang than we 
normally recommend). 
TECHNICAL COMMENTS ON EACH OF THE SIX SITES: 
Hunziker Industrial Site 
• Upgraded parking islands from 5' to 6' to meet minimum code width for planting islands. This shrinks 
some parking stalls, but they still fall within the range allowed for compact parking. 
• Original tree species used were not on the City ' s approved parking lot tree list. Trees with larger canopy 
sizes were also necessary in order to meet minimum parking lot canopy requirements. We would 
recommend a procedure for accepting trees not on the list. 
• This site had a railroad grade along the north property line. A portion of this rail area was within our 
site and the ballast rock and rails precluded using any of this area for planting trees, meaning that more 
trees had to be put elsewhere on site to meet the code. 
• Overall the sight was very tight to fit in the required canopy cover. In order to meet the minimum, we 
had to change all conifers to deciduous (so we could take advantage of their larger canopy size). In this 
particular instance, it would have been nice to keep the conifers for a screen of the rail yard and for year 
around interest. 
Sequoia Landing 
• Upgraded roadside planting strip from 5' to 6' to meet minimum code width. 
• Changed street tree varieties used to match City ' s approved street tree list. 
• Overall, site was very tight. 
• Showing soil volumes on the same plan as site canopy plan makes it crowded and hard to read. On a 
very large site, it seems that this might be better as a separate sheet. Also, we didn ' t do this on all six 
sites. Is there a standard/guideline for when it should be shown? 
• Trees slightly more crowded (i.e. next to utilities, buildings, etc.) than is ideal. 
Broadway Rose 
• Technical note: Using the revision cloud tool to make the existing canopy makes it hard to get exact 
canopy areas for existing trees. 
• Overall site easily averaged minimum requirements. 
Bull Mountain 
• Overall site easily averaged minimum requirements. Did require some adjusting of the street trees to 
meet minimum lot canopy 
Max's Brew Pub 
• Overall Tight if site only existed as one lot (without natural area) 
Masters' Partition 
• Are this many existing trees typical of this kind of development? 
Page 7 
City of Tigard Urban Forestry Code Re,·isions I Volume II I 209 
General Case Study Memo From the "Peer Review" of the Urban Forestry Code for 6 Sites 
• Street trees where the "lag"/private road parcel portion of the property intersect the 3 parcels are way too 
crowded for a real-life situation given the utilities and road access points. 
AKS RECOMMENDED ADDITIONS/CLARIFICATIONS TO THE CODE : 
• Need explanation that existing trees under 6" DBH can be given "planted tree mature crown area" if the 
tree is located with adequate rooting soil and is located within the specified distances from other trees, 
existing buildings, etc. 
• Are wetland areas included or excluded in total site area calculations for required canopy? 
• For street tree canopy calculations, does a tree in the center median area (of a road or a cul-de-sac as at 
Broadway Rose) count toward existing tree canopy area? 
• Define method for canopy area calculations. Potential options would include by fom1Ula using DBH, by 
aerial photo interpretation, or by survey. 
• The list of acceptable trees seems limiting in some situations. Is there a procedure for accepting trees 
not on the list? 
• Within parking lots, is it necessary to calculate the percent canopy cover over the parking lot for each 
individual tree (as opposed to calculating the total canopy cover over the parking lot)? This adds an 
additional step and is time consuming. 
• Showing soil volumes on the same plan as the site canopy makes the sheet crowded and hard to read. 
On a very large site, it seems that this might be better as a separate sheet. Also, we didn ' t do this on all 
six sites per your instruction. Is there a standard/guideline for when it should be shown? 
Page 8 
City of Tigard Urban l;orcstry Code Rc,·isions I \'olumc II I 210 
SHE RWOOD · V 
February 17, 2012 
Todd Prager, AICP, Certified Arborist 
Associate Planner/ Arborist 
City of Tigard, Community Development 
13125 SW Hall Boulevard 
Tigard, Oregon 97223 
P: (503) 92&-8799 F : (503) 92&-8969 
ENGINEERING 8c FORESTRY 
Re: Memorandum-Peer Review of the Implementation of the Proposed Urban Forestry Code 
Revisions to Tree Canopy Requirements for Gertz Homes at Edgewood 1 and Gertz Homes at 
Edgewood 2 
Dear Mr. Prager: 
At the February 6, 2012 Planning Commission Hearing, a member of the public brought forward two examples 
of Tree Canopy Site Plans showing the application ofthe draft Urban Forestry Code Revisions on two sites. 
These were for Gertz Homes at Edgewood 1 and Gertz Homes at Edgewood 2. AKS has reviewed these 
project sites and created alternative Tree Canopy Site Plans using the draft Urban Forestry Code Revisions (see 
attached). Below we will go into detail regarding the contrasts between the example Tree Canopy Site Plans 
provided at the hearing and the Tree Canopy Site Plans developed by AKS Engineering & Forestry. 
For both project sites the draft code requires a minimum of 40% effective canopy coverage on the entire project 
site as well as a minimum of 20% effective canopy coverage on each lot. 
Gertz Homes at Edgewood 1: 
The example Tree Canopy Site Plan for Gertz Homes at Edgewood 1 presented at the hearing showed 27 trees 
being planted on the site. Each of these 27 trees had a mature canopy area of 706.5 square feet. We noted that 
the number of street trees proposed in this plan did not meet the minimum requirements of the draft code. Also, 
it appeared that the trees were placed to provide a minimum of 40% effective canopy coverage on each lot, 
instead of the required 20% effective canopy minimum in the draft code. None of the preserved existing trees 
were shown consistent with the original submittal. The draft code allows the "bonus" of doubling the canopy 
area when preserving existing trees. 
Using the draft code criteria, AKS was able to meet the effective canopy coverage requirements on this site by 
utilizing 12 street trees in addition to preserving the 3 existing trees shown in the original submittal. The 
selection of street trees that have large mature canopy areas (1 ,590 square feet) allowed us to meet the canopy 
Page 1 
City o f Tigard Urban Fore~try Code Revisions I Volume II I 211 
Proposed Urban Forestry Code Revisions Applied to the Gertz Homes at Edgewood Projects 
standards without the use of any additional trees in the front or back yards of the lots. See attached AKS Tree 
Canopy Site Plan for Gertz Homes at Edgewood 1. 
Gertz Homes at Edgewood 2: 
The example Tree Canopy Site Plan for Gertz Homes at Edgewood 2 (directly east of Gertz Homes at 
Edgewood 1) presented at the hearing showed 41 trees being planted on the site. Each of these 41 trees had a 
mature canopy area of 706.5 square feet. It appeared that the trees were placed to provide a minimum of 40% 
effective canopy coverage on each lot, instead of the required 20% effective canopy minimum in the draft code. 
Again, none of the preserved existing trees on site were shown, consistent with the original submittal. In fact, 
the vegetated corridor tract behind lots 10-12 with several preserved existing trees, were not shown on the plan 
presented at the hearing. The draft code allows the "bonus" of doubling the canopy area when preserving 
existing trees. 
Using the draft code criteria, AKS was able to meet the canopy coverage requirements on this site by utilizing 
22 street trees, preserving the 17 existing trees shown in the original submittal, and planting 5 additional 
appropriately placed trees that will not conflict with the use or enjoyment of the lots . See the attached AKS 
Tree Canopy Site Plan for Gertz Homes at Edgewood 2. Note that our calculations for effective tree canopy 
coverage did not include trees that may have been required in the Vegetated Con·idor Tracts 'A' and 'B' to meet 
Clean Water Services standards. 
In conclusion, we feel that with careful attention to the application of the draft Urban Forestry Code Revisions , 
planting plans can be created that result in a reasonable balance between trees, development and open space. 
The two sites peer reviewed in this letter clearly demonstrate this to be the case. 
Very Truly Yours, 
AKS Engineering & Forestry, LL C 
Keith Jehnke, PE, PLS, Principal; 
asa2 
AMERI C A N SOC IETY of 
CONSULT I N!i ARI!ORISTS 
KEITH JEHNKE 
CERTIFIED 
~~ ~\ .....: - ~.... --- -.. --- -- \ 
_ , --
- - , ...... 
- ___.. .. -·. 
- -· ~· · ....... 
- 1 -,
ARBORIST 
CERTIFI CATE NUMBER PN- 1908 
EXPIRATION DATE: 6/30/20 13 
Certified Arborist #PN-1908, Certified Tree Risk Assessor #192 
Member, American Society of Consulting Arborists 
City o iTiga rd Urban Forestry Code Rc,·isions I \ 'olumc II I 212 
Page 2 
!REVISIONS: 
D QUALIFYING MATURE CANOPY COVER 
- ~· "" ~· ~ QUALIFYING EXISTING MATURE CANOPY COVER 
$ ... 5 ... CA$ Go\$ -~ 01-'W s....~ r:MJ~  ;:...RA....:0"~,!~/~~H(TYP.) ------ - INDIVIOUALTREEMATURE CANOPY OUTLINE 
EXISTING TREE CANOPY (TYP. 
r 
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SITE TREE CANOPY PLAN 
LOT # 
LOT 1 
LOT 2 
LOT 3 
LOT 4 
LOT 5 
LOT 6 
~ EXISTING TREE CANOPY OUTLINE 
TOTAL SITE AREA: 47 ,384 S.F. 
TOTAl QUALIFYING MATURE TREE CANOPY AREA: 23,499 S.F. 
% CANOPY COVER: 50% 
MINIMUM % CANOPY COVER: 40% 
50% IS GREATER THAN THE MINIMUM OF 40% TOTAL QUALIFYING 
MATURE CANOPY COVER FOR THE SITE, THEREFORE CITY 
REQUIREMENTS ARE MET. 
REQUIRED CANOPY ACTUAL CANOPY 
LOT AREA 1 S.F i COVERAGE ~ S.F J ! 20~ COVERAGE { S.FJ%~ 
7,578 1.516 5.301 ( 70%) 
8 ,286 1,657 3,180 (38%) 
7 ,607 1,521 3.180 ( 42%) 
6,990 1.398 1,590 ( 23%) 
7,392 1,478 3.180 ( 43%) 
9,531 1,906 7,068 ( 74%) 
TREE CANOPY TABLE 
PLANTED TREE CANOPY 
TREE# SPECIES TOTAL SOIL VOLUME AVE. MATURE CANOPY fFTISF) QUALIFYING SITE CANOPY 
10000 Raywood Ash 
10001 Raywood Ash 
10002 Raywood Ash 
10003 Red Oak 
10004 Red Oak 
10005 Red Oak 
10006 Red Oak 
10007 Red Oak 
10008 Red Oak 
10009 Red Oak 
10010 Red Oak 
10011 Red Oak 
EXISTING TREE CANOPY 
TREE# SPECIES 
10100 Douglas Fir 
10101 Douglas Fir 
10102 Big Leaf Maple 
O..er 1,000 c .f 30' spread -A- 707 s.f. 
'V' 
Owr 1,000 c.f 
0\er 1,000 c .f. 
0\oer 1,000 c. f. 
Owr 1,000 c.f. 
Owr 1.000 c. f. 
O..er 1,000 c.f 
0-.er 1,000 c .f 
0\Eir 1,000c.f 
O...er 1.000 c f. 
Owr 1,000 c f. 
0-.er 1,000 c .f 
TOTAL SOIL VOLUME 
0-..er 1,000 c .f. 
0-..er 1,000 c. f 
0\Eir 1,000c.f 
30' spread 707 
30' spread 707 
45' spread 1,590 
45' spread 1,500 
45' spread 1,590 
45' spread 1,590 
45' SPf88d 1.590 
45' spread 1.590 
45' spread 1,590 
45' spread 1,590 
45' spread 1,500 
SITE CANOPY SUBTOTAL 
CANOPY IFT/SFI 
50' Spl'"ead 1.004 
40' spread 1,256 
20' spread 314 
EXISTING SITE CANOPY SUBTOTAL 
TOTAL QUALIFYING SITE TREE CANOPY AREA 
KJ )()( 
707 sf. 
707 s.f. 
1,500 s.f. 
1,500 s.f. 
1,500 s.f. 
1.590 s.f 
1,500 s.f. 
1,500 s.f 
1.590 s.f 
1.590 s.f. 
1,590 sf. 
16 431 s.f. 
QUALIFYING SITE CANOPY 
1,004 s.f. 
1,246 s.f. 
314 s.f. 
3,534 s.f. X 2 = 7,068 s.f. 
23 499 s.f. 
KAH AS NOTED 
KJ 
PREPARED FOR: 
TIGARD 
Cit}' of Tigard Urban Forestry Code Revisions I \'olume II I 21.3 
STIEET TIEES 
SYIIOOL arB OOTN41CAl NolliE C()ljlj()N NolliE COOOITION SIZE SPACING §: lllAXINUS O'f!fCAAPA 'RAIWOOO' RAYWOOO ASH B&B 2" CAL AS SHOWN QUERCUS R\.IIRA RED OAX Boi:B J" CAL AS SHOWN 
L.EQEN) 
EXISTING SN4ITIMI' 
PROPOSED SN4ITIMI' 
EXISTING WATER 
PROPOSED WATER 
EXISTING STORII 
PROPOSED STORII 
EXISTING Tll£POONE 
EXISTING <MRI£Ail WilE 
EXISTING l'llW£R 
EXISTING GAS 
DA 
JOB NUMBER 
EDGEWOOD NO. 1 XX 
SHEET 
OREGON 1 OF 1 
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' 17 I 
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7 8 
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"GERTZ HOMES AT 
D QUALIFYING MATURE CANOPY COVER S'mEET Tl1EES SYWBOl onES. OOTANIC.IL NAIIE 
~ Q 5 CI:RCIIJlPHYllllll JAPONICUW QUALIFYING EXISTING MATURE CANOPY COVER 17 ClJDRAST1S I([NTUKEA 
INDIVIDUAL TREE MATURE CANOPY OUTLINE SITE TREES 
SYWBOl OnES. OOTANIC.IL NAIIE 
~ EXISTING TREE CANOPY OUTLINE ~: ACER TRUNCATUW X A PlATANOIDES TOTAL SITE AREA: 108.390 S.F. TOTAL QUALIFYING MATURE TREE CANOPY AREA: 56,819 S.F. RHAMh\JS PIJRSHANA %CANOPY COVER: 52% MINIMUM % CANOPY COVER: 40% 
52% IS GREATER THAN THE MINIMUM OF 40% TOTAL QUALIFYING 
QUERCUS RUBRA 
MATURE CANOPY COVER FOR THE SITE , THEREFORE CITY 
REQUIREMENTS ARE MET. 
REQUIRED CANOPY ACTUAL CANOPY 
LOT # LOT AREA ! S.F ~ COVERAGE ' S.F ~ ' 20%! COVERAGE ! S.F J%~ 
LOT7 7.544 1,508 4.436 ( 59%) 
LOT 8 7.486 1,497 2,886 ( 39%) 
LOT 9 9.210 1.842 5.204 ( 57%) 
LOT 10 10.308 2 .061 2.553 ( 25%) 
LOT11 8 ,355 1,671 4 ,890 ( 59%) 
LOT 12 7.356 1,471 1,590 (22%) 
LOT 13 6.005 1,201 1,453 (24%) 
LOT 14 6.026 1.205 1,453 (24%) 
LOT 15 6.066 1.2 13 6 .696 ( 11 0%) 
LOT 16 6 ,158 1,232 4.142 (67%) 
LOT 17 9,382 1,876 1,924 (21%) 
LOT 18 6,307 1,261 4.730 ( 75%.) 
TRACT "A" 17,199 3.410 14.371 ( 84%) 
TRACT £3" 988 198 491 ( 50%) 
NOTE: TREES REQUIRED TO MEET CLEAN WATER SERVICES REQUIREMENTS IN THE 
VEGETATED CORRIDOR ARE NOT INCLUDED IN THESE CALCULATIONS. 
!REVISIONS: 
' 
' I 
' 
' I 15 I 
9 
lOT 4 
EDGEWOOD " 
COIAION NAIIE CONOOION 
KATSURA B&B 
YEUOWOOO B&B 
COIAION NAWE CONOOION 
SUNS£! WAPlE B&B 
OSCAAA B&B 
RED OAK B&B 
-----~~ 
' ®. I ,' 1CJ(X)9 11 
- ,,_ -r ~ . . .. ... ~ --.. 
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' I 14 13 
TRACT "B" 
12 
---
"A" 
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---
11 
------ ----- -
10 
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LOT 6 LOT 5 LOT 4 101 ) lOT 2 
\.___ J 
I "MCDONALD WOODS " 
I 
SIZE SPACING TREE CANOPY TABLE 
1" CAL A5 SHOWN PLANTED TREE CANOPY EXISTING TREE CANOPY 
2" CAL A5 SHOWN 
SIZE SPAClNG 
2" CAL A5 SHOWN 
2" CAL A5 SHOWN 
2" CAL A5 SHOWN 
TREE# SPECIES TOTAL SOIL VOLUME AVE. MATURE CANOPY {FT/SF} QUALIFYING SITE CANOPY TREE# SPECIES 
10000 Katsura O~oer 1,000 c.f. 40" spread 1,256 1,256 s.f. 10100 Costal Redwood 
10001 Katsura O~oer 1,000 c. f. 40' spread 1,256 1,256 s.f. 10101 Western Red Cedar 
10002 Kat sura O~oer 1,000 c. f. 40' spread 1,256 1,256 s.f. 10102 Douglas Fir 
10003 Yello.ood O""r 1,000 c. f. 35' spread 962 962 s.f. 10103 Sequoia 
10004 Yello.ood o""r 1,000 c. f. 35· spread 962 962 s.f. 10104 Sequoia 
10005 Yello.ood O""r 1,000 c. f. 35· spread 962 962 s.f. 10105 Western Red Cedar 
10006 Yello.ood O""r 1,000 c. f. 35· spread 962 962 s.f. 10106 Bigleaf Maple 
10007 Yello.ood O""r 1,000 c. f. 35' spread 962 962 s.f. 10107 Western Red Cedar 
10008 Sunset Maple O""r 1,000 c.f. 25' spread 491 491 s.f. 10108 Western Red Cedar 
10009 Sunset Maple O""r 1,000 c.f. 25' spread 491 491 s.f. 10109 Unknown Deciduous 
10010 Yellowood O""r 1,000 c. f. 35' spread 962 962 s.f. 10110 Unknown Deciduous 
10011 Yello.ood O~oer 1,000 c. f. 35' spread 962 962 s.f. 10111 Unknown Deciduous 
10012 Red Oak O~oer 1,000 c. f. 45' spread 1,590 1590 s.f. 
10112 Unknown Conifer 
10013 Cascara O""r 1,000 c. f. 25' spread 491 491 s.f. 10113 Unknown Decidoous 
10014 Yello.ood O""r 1,000 c. f. 35' spread 962 962 s.f. 10114 Unknown Decidoous 
10015 Yello'M>Od O""r 1,000 c. f. 35' spread 962 962 s.f. 10115 Unknown Decidoous 
10016 Red Oak O~oer 1,000 c. f. 45' spread 1,590 1,590s.f. 10116 Unknown Conifer 
10017 Yellov.ood O..er 1,000 c. f. 35' spread 962 962 s.f. 
10018 Yellov.ood O..er 1,000 c. f. 35' spread 962 962 s.f. 
10019 Yellov.ood O""r 1,000 c. f. 35' spread 962 962 s.f. 
10020 Yellov.ood O;er 1,000 c.f. 35' spread 962 962 s.f. 
10021 Yellov.ood O""r 1,000 c. f. 35' spread 962 962 s.f. 
10022 Yellov.ood O""r 1.000 c.f. 35' spread 962 962 s.f. 
10023 Yello'M>Od O""r 1,000 c. f. 35' spread 962 962 s.f. 
10024 Yello'M>Od O""r 1,000 c. f. 35' spread 962 962 s.f. 
10025 Katsura O""r 1,000 c.f. 40' spread 1,256 1,256 s.f. 
10026 Katsura O""r 1,000 c. f. 40' spread 1,256 1,256 s.f. 
SITE CANOPY SUBTOTAL 27.287 s.f. 
KJ XX 
KAH A5 NOTED 
TOTAL SOIL VOLUME 
O~oer 1,000 c.f. 
O~oer 1,000 c.f. 
O""r 1,000 c. f. 
O""r 1.000 c. f. 
O""r 1,000 c.f. 
O""r 1,000 c.f. 
O""r 1,000 c.f. 
O""r 1,000 c. f. 
O""r 1.000 c. f. 
O""r 1.000 c. f. 
O""r 1,000 c.f. 
O~oer 1,000 c.f. 
O""r 1,000 c.f. 
O""r 1,000 c.f. 
O""r 1,000 c. f. 
O""r 1,000 c. f. 
O""r 1.000 c.f. 
~ 
SCALE !" - 30 FEET 
----I Jlll't ~ A 
lEGEN) 
EXISliNG SANITARY 
PRQPQS[I) SANITARY 
EXIS1ING WAT£R 
PROPQS[O WAT£R 
EXISliNG SlORII 
PRQPQS[I) SlORII 
EXISliNG GAS 
CANOPY {FTISF} QUALIFYING SITE CANOPY 
45' spread 1,590 1,590s.f. 
25' spread 491 491 s.f. 
35' spread 962 962 s.f. 
30' spread 707 707 s.f. 
30' spread 707 707 s.f. 
30' spread 707 707 s.f. 
40' spread 1.257 1,257 s.f. 
30' spread 707 707 s.f. 
24' spread 452 452 s.f. 
35' spread 962 962 s.f. 
35' spread 962 962 s.f. 
35' spread 962 962 s.f. 
30' spread 707 707 s.f. 
35' spread 962 962 s.f. 
35' spread 962 962 s.f. 
35' spread 962 962 s.f. 
30' spread 707 707 s.f. 
EXISTING SITE CANOPY SUBTOTAL 14,766 s.f. x 2 = 29,532 s.f. 
TOTAL QUALIFYING SITE TREE CANOPY AREA 56.819 s.f. 
'ATE: 
EDGEWOOD NO. 2 KJ CANOPY PLAN SITE TREE PREPARED FOR: 
TIGARD OREGON 
City of Tigard Urban l'orestry Code Rc,-isions I Volume II I 215 
JOO NU~BER 
XX 
SHEET 
1 OF 1 
Project Sites Submitted (Edgewood 1 & 2) During Testimony at the 
February 6, 2012 Hearing 
Note: Coverage 0/o would be much if a Water Quaf:ity Facility 
was included in calculations 
Note: Several trees are shown closer than code allows 
TREE CANOPY AT 40°/o COVERAGE R-4.5 
•Aissbg Items. 
Slleet • i;h t:s 
Fire H yd•ont s 
Lo Ym Areas 
Plo y A•eos 
P•oy Suuct:J res 
Swimrn ng Pools 
Spo•l Cour ts 
Gorden Plot 
t..J -~EESI 
..s 3 TRE.ES 
Over Plor t !fd 
.3 lRCES 
Over Plont l!d 
4.3 iRE.t:.S 
Over Plcnted 
Doe~n' 
Edgewood 1 
l.tll 40'% 
, 7!186 3034 
2 8266 331C 
3 7605 3042 
4 6952 278 1 
5 735$ 2~2 
6 !i521 3806 
7 7$4.4 Ja1 8 
8 14M 2994 
9 92 10' 35&6 
14 6026 2A10 
15 6055 2426 
10 !1158 2.a::l 
17 11382 3753 
10 f307 2!i:ll 
706 S SF Treet 
" ~ 
4 68 
4 l 1 
3 94 
4 16 
5 ~9 
• 27 
4 24 
5 21 
l 41 
l ~3 
3 <49 
5. 31 
H 1 
REQUIRED STREET TREES 
LEFT IN PLACE 
.. 
a..ooo 
Edgewood 2 
J 6 "'R[ES 
5 J TREES 
Over Plo"tec 
3 5 lRETS 
O"er Planted 
"REfS 
Plon ! ed 
.3 4 TREES 
Ove• Pia., te" 
City of Tigard Urban Forestry Code Re,·isions I Volume 11 I 217 
" E 
2 
c 
;:... 
Urban Forestry Code Revisions 
Tree Grove ESEE Analysis 
City of Tigard Urban Forestry Code Revisions I Volume II I 219 

To: 
From: 
Re: 
D ate: 
City ofTigard 
Memorandum 
Urban Forestry Code Revisions Project Management Team 
Darren Wyss, Senior Planner 
Tree Grove Preservation Program 
December 12, 2011 
The Urban Forestry Code Revisions (UFCR) project included the development of a Tree Grove 
Preservation Program. This was identified as a top priority of the community during the Tigard Urban 
Forestry Master Plan (UFMP) process . The intent is to preserve Tigard's remaining groves of native trees 
through a flexible and incentive-based program, while allowing for the full development of property under 
current zoning. 
The program was developed following State Goal 5 rules, which are specific about process and evidence 
requirements needed to adopt land use regulations intended to protect natural resources. Even though the 
city's approach to tree grove preservation is proposed to be flexible and incentive based, it must meet the 
same Goal 5 standards as if a more regulatory approach was intended. 
An important component of the Goal 5 process is conducting an Economic, Social, Environmental and 
Energy Analysis (ESEE). The ESEE considers alternative program options (protect, allow, limit) and is used 
to support Goal 5 decisions. The Tigard ESEE supports the proposed limited protection option that is part 
of the UFCR project. 
City o f Tigard Urban Forestry Code Revisions I Volume II I 221 
('] 
('] 
"' 
Tigard Goal 5 ESEE Analysis for 
Significant Tree Groves 
TABLE OF CONTENTS 
Section 1 - Introduction and Context .............................................................. 1 
Glossary of Terms and Acronyms Used in this Report ...................................... 1 
Tigard Planning Terms ................................................................................................ 1 
Tigard Urban Forestry Project Terms ............................................................................ 1 
Metropolitan Service District (Metro) Terms .................................................................. 2 
Tualatin Basin Partners for Natural Places Terms .......................................................... 2 
Statewide Planning Goal 5 (Natural Resource) Terms .................................................... 3 
Report Organization ........................................................................................ 4 
Tigard's Interest in Protecting Significant Tree Groves (STGs) ....................... 4 
Statewide and Regional Planning Context ....................................................... 5 
Statewide Planning Goal 5 - Natural Resources ............................................................. 6 
Tigard Tree Grove Assessment Report ............................................................. 6 
Tree Grove Inventory Results ...................................................................................... 8 
Significance Determination .......................................................................................... 9 
Impact Area Determination .......................................................................................... 9 
Section 2- Conflicting Use and Draft Limited Protection (Regulatory 
Incentives} Program ..................................................................................... 2-1 
Introduction .................................................................................................. 2-1 
Methods for Identifying Conflicting Uses ...................................................... 2-1 
Primary Tigard Development Districts (Zoning)- Uses ................................................ 2-2 
Tigard's Existing Natural Resource Protection Program ............................................... 2-3 
Vegetation Removal, Grading and Construction of Impervious Surfaces ....................... 2-5 
Conflicting Use Matrix - by Significant Tree Grove ....................................... 2-6 
Section 3 - Tigard ESEE Analysis for STGs ..................................................... 3-1 
Introduction .................................................................................................. 3-1 
Goal 5 Rule Requirements ........................................................................................ 3-1 
Tigard ESEE Approach ................................................................................... 3-2 
Correlation among Goal 5 ESEE Factors and Goals 1-15 ............................... 3-2 
Statewide Planning Goal Analysis ................................................................. 3-4 
Goal 1: Citizen Involvement ............... ....................................................................... 3-4 
Goal 2: Land Use Planning ........................................................................................ 3-7 
Goal 5: Natural Resources ...................................................................................... 3-11 
Goal 6: Air, Land and Water Resource Quality .......................................................... 3-20 
Goal 7: Natural Hazards ......................................................................................... 3-26 
Goal 8: Recreational Needs ..................................................................................... 3-29 
Goal 9: Economy of the State ................................................................................. 3-31 
Goal 10: Housing ................................................................................................... 3-36 
Goal 11: Public Facilities and Services ..................................................................... 3-43 
Goal 12: Transportation .......................................................................................... 3-46 
City of Tigard Urban Forestry Project 
ESEE Analysis • Table of Contents 
Prepared by Winterbrook Planning 
November 2011 
City of Tigard Urban l'orestry Code Re,·isions I Volume II I 223 
Page i 
Goal 13: Energy Conservation ................................................................................. 3-48 
Goal 14: Urbanization ............................................................................................. 3-53 
Section 4- Proposed Limited Protection (Regulatory Incentives) ............... 4-1 
Proposed TDC Chapter 18.790.050 Revisions ............................................................. 4-1 
STG Regulatory Incentives Scenarios ...................................... .. ................................. 4-3 
Map A: Significant Tigard Tree Groves and Impact Areas 
Map B: Significant Tree Groves with Corresponding Tigard Comprehensive 
Plan Designations 
Map C: Significant Tree Groves in Relation to Regulated (Title 3), and Non-
Regulated (Title 13) Sensitive Lands 
Appendix A Tigard Tree Grove Assessment Report 
Appendix B Impacted Taxlots and Significant Tree Grove Acreage 
City of Tigard Urban Forestry Project 
ESEE Analysis • Table of Contents 
Prepared by Winterbrook Planning 
November 2011 
City of Tigard Urban l'orcstry Code Rc,·isions I \'olumc II I 224 
Page ii 
Section 1 - Introduction and Context 
This report addresses Statewide Planning Goal 5 - Natural Resources (Goal 5) 
requirements for protection of Significant Tree Groves (STGs) as shown on Map A: 
Significant Tree Groves and Impact Areas. Goal 5 requirements should be considered in 
the context of Tigard's current Goal 5 program and the Tigard Development Code's 
existing "Sensitive Lands" chapter which implements Metro functional plan requirements 
(Titles 3 and 13). This report supports the Council's goal of protecting STGs through an 
incentive-based program that complements Tigard's existing zoning regulations. 
Glossary of Terms and Acronyms Used in this Report 
The report necessarily incorporates terms of art and acronyms from Goal 5, the 
Metropolitan Service District (Metro), and the City of Tigard's comprehensive plan and 
land use regulations. The following terms and acronyms are used throughout this 
report. 
Tigard Planning Terms 
• Tigard Comprehensive Plan (comprehensive plan)- the controlling long-range 
planning document for the City of Tigard. 
• Tigard Development Code (TDC) -the land use regulations that implement the 
comprehensive plan. 
• Tigard Economic Opportunities Analysis (EOA) - a study adopted by the City of 
Tigard in May of 2011. The EOA includes economic trend analysis, projections 
and policies; it also includes a comparison of 20-year need for employment land 
with the supply of buildable employment sites in Tigard. 
• Tigard Sensitive Lands(Sensitive Lands) -land and water areas protected by 
TDC Chapter 18.775- Sensitive Lands. Chapter 18.775 is an overlay district that 
implements Metro Titles 3 and 13 and already provides limited protection to most 
STGs. 
• Tigard Transportation System Plan (TSP) - a long-term plan that identifies the 
location, timing and funding for multi-modal transportation facilities. 
Tigard Urban Forestry Project Terms 
• Urban Forestry Master Plan (UFMP) - makes recommendations for implementing 
the comprehensive plan and includes background information and objectives for 
urban forestry management. 
• Tree Grove Preservation Project- authorized by UFMP objectives and includes a 
tree grove inventory, ESEE analysis, and comprehensive plan and TDC revisions. 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 1. Introduction and Content 
Prepared by Winterbrook Planning 
November 2011 
City of Tigard Urban Forestry Code Re,·isions I Volume II I 225 
Page1-1 
• Significant Tree Grove (STG)- one of 70 locally STGs totaling 544 acres within 
the Tigard City Limits. Most STGs are within, or partially within, areas already 
protected by Tigard's Sensitive Land regulations. 
• Urban Forestry Code Revisions Project- includes (among other things) draft 
amendments to the TDC Chapter 18.790 Urban Forests related to tree grove 
regulatory incentives. 
• Urban Forestry Code Revisions Citizens Advisory Committee (CAC)- makes 
recommendations regarding, among other things, an incentives-based program 
to protect STGs. 
• Tigard Tree Grove Assessment Report (Tree Grove Assessment) - a Goal 5 
inventory report prepared by Winterbrook Planning in 2010 that maps and 
describes the location, quality (functional characteristics) and quantity of 70 
STGs within the Tigard City Limits. 
• Tigard's Proposed Urmted Protection Program (Regulatory Incentives 
Program)- the program recommended by the CAC for adoption into TDC 
Chapter 18.790 Urban Forests to supplement Tigard's Sensitive Lands program. 
Metropolitan Service District (Metro) Terms 
• Metro Title 3- Water Quality and Flood Management (Title 3) -a mandatory 
regulatory program adopted by Metro that applies to mapped Water Quality 
Resource Areas within the regional Urban Growth Boundary, including the City of 
Tigard. Title 3 is implemented by Tigard's Sensitive Lands district and already 
protects portions of STGs in Tigard. 
• Metro Title 13- Nature in the Neighborhoods (Title 13) - applies to mapped 
Habitat Conservation Areas (HCA) within the regional Urban Growth Boundary, 
including the City of Tigard. Tigard's Sensitive Lands district implements Title 13 
and offers a limited incentives to protect "significant habitat areas" consistent 
with Tualatin Basin Partners recommendations. 
Tualatin Basin Partners for Natural Places Terms 
• Tualatin Basin Goal 5 Program Implementation Report(Tualatin Basin 
Program)- the results of a coordinated effort by an alliance of eight 
Washington County cities (including Tigard), Washington County, Metro, the 
Tualatin Hills Park and Recreation District (THPRD), and Clean Water Services 
(CWS) to address Metro Title 13 requirements by adopting "habitat-friendly 
development practices" and related incentive-based measures. Tigard amended 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 1. Introduction and Content 
Prepared by Winterbrook Planning 
November 2011 
Citv ofTiganl Urban l'orcstry Code Rc,·isions I \'olumc II I 22(, 
Page1-2 
its Sensitive Land regulations in January of 2007 to implement some of the 
Tualatin Basin Program recommendations. 
• Tualatin Basin Goal 5 ESEE Analysis (Tualatin Basin ESEE Analysis) -
considered the economic, social, environmental and energy consequences of 
alternative program options for "protecting" significant riparian corridors and 
wildlife habitat areas, and their impact area (the entire Tualatin River Basin). The 
Tualatin Basin ESEE Analysis supports the recommendations of the Tualatin 
Basin Report and the CAC's proposed Regulatory Incentives Program. 
Statewide Planning Goal 5 (Natural Resource) Terms 
• OAR Chapter 660, Division 023 (the Goal 5 rule) - an administrative rule 
adopted by the Land Conservation and Development Commission (LCDC) that 
interprets and implements Goal 5. 
• Significant Goal 5 Resource Site- for the purposes of this ESEE Analysis, one of 
70 STGs that have been inventoried and determined significant in the 2010 Tree 
Grove Assessment. 
• Conflicting Use- a land use or related activity permitted by applicable Tigard 
base and overlay zoning districts that could conflict with one or more functional 
characteristics identified for STGs in the Tigard Tree Grove Assessment. 
• Impact Area- an area outside the resource site where permitted uses could 
adversely affect the identified resource (in this case, the STG). For purposes of 
this ESEE Analysis, the impact area includes properties (tax lots) on which the 
STG is located and where development could directly impact an STG. 
• Economic, Social, Environmental and Energy consequences analysis (ESEE 
analysis). A goal 5 ESEE analysis that considers alternative program options 
(full protection, limited protection and no additional protection) that supports 
adoption of Tigard's proposed limited protection, Regulatory Incentives Program. 
• Goal 5 Program Decision Options . .J 
o Protect resource fully(full protection)- adopt additionaltree grove 
regulations that prohibit all conflicting uses - including those currently 
allowed by existing Sensitive Land regulations. 
o Allow conflicting uses fully(no additional protection)- allow 
conflicting uses without additional regulations or incentives (beyond those 
provided by Tigard Sensitive Lands regulation) to protect STGs. 
1 The Tualatin Basin ESEE Analysis uses the terms "prohibit" (full protection), "allow" (no additional protection), and 
"limit" (limited protection). 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 1. Introduction and Content 
Prepared by Winterbrook Planning 
November 2011 
City of Tigard Urban Forestry Code Rc,-isions I Volume II I 227 
Page1-3 
o Allow conflicting uses on a limited basis (limited protection)- adopting 
additional regulations and/or incentives that further limit conflicting uses 
allowed by existing regulations. 
Report Organization 
The report is organized in three sections: 
• Section 1 describes how the tree groves protection project relates to the 
remainder of Tigard's urban forestry program, defines key terms and acronyms, 
summarizes Goal 5 planning requirements as they pertain to tree groves, 
summarizes the results of Tigard's 2010 tree grove inventory and the basis for 
the City's determination of resource significance, and defines the "impact area" 
for assessing the ESEE consequences of alternative resource protection options. 
• Section 2 identifies urban uses and activities that conflict with the full protection 
of STGs in the context of regional and local planning requirements. 
• Section 3 analyzes the ESEE consequences of three decision options for tree 
grove management: full resource protection (prohibit all conflicting development 
within an STG), limited resource protection (the City's proposed Regulatory 
Incentives Program), or no additional resource protection (do nothing beyond 
existing Sensitive Land regulations to protect STGs). Section 3 also includes 
findings demonstrating continued compliance with applicable Statewide Planning 
Goals (i.e., Goals 1-2 and 5-14). 
• Section 4 describes Tigard's proposed limited protection (regulatory incentives) 
program, which is designed to encourage property owners and developers to 
protect all or part of STGs through density transfer, relaxation of dimensional 
standards (such as setback and building height), and flexible development 
standards. 
Tigard's Interest in Protecting Significant Tree Groves (STGs) 
Tigard takes urban forestry seriously and is justifiably proud to be recognized as a "Tree 
City USA". Recent amendments to the comprehensive plan call for protection of tree 
groves -while respecting individual property rights and encouraging appropriate urban 
infill. The City's Urban Forestry Master Plan (UFMP, November 2009) underscores 
Tigard's commitment to the comprehensive management of Tigard's 1,853 acres of 
existing tree canopy through a variety of methods - including incentives-based 
protection for STGs. 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 1. Introduction and Content 
Prepared by Winterbrook Planning 
November 2011 
City of Tigard Urban l'orcstry Code Re,·isions I \'olume II I 22H 
Page1-4 
Despite these accomplishments, Tigard has had only moderate success in actually 
protecting large tree groves - especially those lying outside of protected Title 3 Sensitive 
Lands areas. The UFMP (p. 17) includes a map and matrix documenting changes in tree 
canopy from 1996- 2007. Although the total acreage of canopy cover has decreased 
by approximately 100 acres (from 1,953 to 1,853), the distribution of tree canopy by 
area has changed substantially. There are more small groves (2 acres or fewer) and 
fewer large groves (5.0 acres or more). In 1996, Tigard had 1,100 acres in large tree 
groves; by 2007, there were only 766 acres- a 30% decline. 
The UFMP includes six "goals"- with corresponding sub-goals and action measures. 
The UFMP's "implementation matrix" identifies the lead City division, cites supportive 
comprehensive plan policies, and provides information related to commitment of staff 
resources, relative costs, and timing. This background information sets the stage and 
policy context for the Tigard Tree Grove Protection Project. 
Goal 3 of the UFMP is to "develop a tree grove protection program."2 There are two 
sub-goals: 
3.1 Focus on preserving large groves of native trees. 
3.2 Develop a flexible and incentive based grove preservation program 
that meets the needs of affected property owners. 
Tree groves are scenic and open space resources that must be inventoried, analyzed 
and protected consistent with Goal 5. As noted in Section 4, Tigard's local program to 
achieve Sub-goals 3.1 and 3.2 also should be considered in the context of Metro, 
Tualatin Basin, and local planning efforts - which already provide limited tree grove 
protection in designated "Sensitive Lands" areas. 
Statewide and Regional Planning Context 
Goal 5 sets forth procedures that local governments must follow when developing 
programs to protect natural resources. Metro Titles 3 and 13 inventories and programs 
overlap considerably with STGs inventoried in the Tigard Tree Grove Assessment and 
the CAC's recommendations for a regulatory incentive program. These programs (as 
implemented by Tigard's Sensitive Land regulations, serve as the baseline for Tigard's 
Tree Grove Protection Project and are discussed further in Section 3. 
2 Complementary goals include (1.) revise the City's tree code; (2) revise the City's landscaping code; (4) develop a 
hazardous tree program; (5) improve the management of the City's urban forestry program; and (6) develop an 
urban forestry stewardship program. 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 1. Introduction and Content 
Prepared by Winterbrook Planning 
November 2011 
City of Tigard Urban f'orestry Code Revisions I Volume II I 229 
Page1-5 
Statewide Planning Goal 5- Natural Resources 
Goal 5 requires local governments to inventory and protect significant natural and scenic 
resources - including STGs - based on an analysis of the ESEE (economic, social, 
environmental and energy) consequences of alternative protection options. 
The Goal 5 administrative rule establishes specific requirements for conducting natural 
resource inventories, determining the significance of resource sites and their "impact 
areas", identifying conflicting urban uses and activities, conducting the required ESEE 
analysis, and developing a local protection program. 
Although "tree groves" are not specifically mentioned in the Goal 5 rule, STGs may be 
classified as both "open space" and "scenic" resources. The "open space" category 
includes "forests" and "wildlife preserves"; the scenic resources category includes "lands 
valued for the aesthetic appearance." (OAR 660-023-0110 and 0220). However, the 
decision to inventory and protect STGs as open space and scenic resources is optional 
on the part of local government. This decision is based on Council policy - not state or 
regional mandate. 
Nevertheless, if a local government decides to inventory and protect open space and 
scenic resources (as Tigard has done in the case of STGs), the Goal 5 process must be 
followed by conducting a tree grove inventory, determining local significance, identifying 
conflicting uses for resource sites and their impact areas, analyzing ESEE consequences 
of protection options, and adopting a local protection program. 
Unlike some other statewide goals, Goal 5 is essentially procedural in nature; the Goal 5 
rule establishes a conflict resolution process that seeks to balance urban development 
and resource conservation objectives. Importantly, Goal 5 does not mandate a specific 
outcome; rather it requires each local government to consider the consequences of 
three protection options before making a decision regarding the appropriate level of 
local resource protection. 
The remainder of this section describes the inventory process and results, the basis for 
the City's "significance" determination, and the impact areas for STGs. Section 2 of this 
ESEE Analysis goes on to identify conflicting uses and activities and describe the City's 
draft limited protection program in the context of Metro and Tualatin Basin Goal 5 
programs. Section 3 includes the required Goal 5 ESEE analysis and findings 
demonstrating compliance with applicable statewide planning goals. 
Tigard Tree Grove Assessment Report 
The City of Tigard Tree Grove Assessment Report(Winterbrook Planning, 2010) 
documents the location, quantity and quality of STGs in Tigard. As documented in the 
Tree Grove Assessment itself, Winterbrook inventoried tree groves as prescribed by the 
the Goal 5 rule (OAR 660-023-0030). 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 1. Introduction and Content 
Prepared by Winterbrook Planning 
November 2011 
C:ity of 'J'iganl Urban l'orc>try Code Rc,·i>iom I \ 'olumc I I I 2311 
Page1-6 
City planning staff worked with Winterbrook to select potential significant tree groves for 
initial review. The City used Metro tree canopy maps and GIS technology to identify tree 
groves with a canopy cover of two acres or greater. Using this criterion alone, City staff 
determined that there were 100 tree groves in Tigard, covering approximately 930 acres 
-or about 12.3% of the City's land area. Winterbrook reviewed aerial photographs and 
boundaries of the initial 100 tree groves to refine Metro canopy mapping. Metro's 
canopy mapping software does not always differentiate developed areas with buildings 
and roads, tree shadows, and other landscape patterns that are not trees. Therefore, 
Winterbrook removed developed and non-forested areas from the City's inventory. 
Winterbrook then completed field inventory forms and conducted on- and off-site 
inventories for potential STGs. Ten functional characteristics were evaluated for each 
resource site. The range of potential scores for a given grove is 10 to 50 points. 
Following is a summary of the 10 functional categories and their assessment factors. 
• Grove Maturity I Tree size. Scenic values tend to be a function of tree size or 
age. Also, mature trees are difficult or take a long time to replace. The primary 
assessment factor in this category is the percentage of large trees (greater than 
14" diameter at breast height (dbh)) in the grove. Multi-stem trees are 
evaluated by the size of the largest individual trunk at chest height. 
• Grove Size. The vitality and resilience of a grove generally increases with grove 
area. Scenic, natural and other values often increase with size as well. Based on 
local grove conditions, groves of greater than five acres are defined as large 
(high), groves between two and five acres are defined as medium, and groves of 
less than two acres are defined as small (low). 
• Health. This category assesses the general health and condition of a grove, 
including signs of dieback, threats, and disturbance. Threats may include 
infestations of invasive plants such as English ivy that tend to degrade tree and 
grove health. It may also include natural processes, such as beaver activity, that 
change the hydrologic regime to alter the existing tree grove composition and 
health. 
• Visibility. Groves that are clearly visible from major streets or public open space 
have greater value to the community. Assessment factors include visibility from 
an arterial or local street and/or public or private open space. 
• Screening/Buffering. Groves may serve as land use buffers. The value of 
buffering or screening is a function of the grove size, location and nearby uses. 
The greatest value to the community is when the tree grove provides a buffer 
between different types of uses, primarily between industrial/commercial use and 
residential/open space uses. 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 1. Introduction and Content 
Prepared by Winterbrook Planning 
November 2011 
City of Tigard Urban Forestry Code ReYisions I Volume ll I 231 
Page1-7 
• Accessibility. Accessibility is a function of ownership (public or private) and 
physical features (topography, trail access, etc.). Public access provides more 
opportunity for public use and enjoyment. Steep terrain and inaccessible 
features (wetlands, dense brush) may limit or preclude opportunities for public 
use. 
• Rarity. Unusual features, such as large size, rare species, or historic/landmark 
values, add to community value. This category considers whether such features 
are present, and whether they are uncommon or unique within the City. 
• Educational/ Recreational Potential. Groves with both public access and 
noteworthy features offer increased educational values. Groves with public or 
semi-public access and trail networks offer passive recreation values. Important 
factors include public versus private ownership and whether developed access 
exists. This category is a function of accessibility and rarity values: if either ranks 
low, this function is low; if both rank medium, this function is medium; 
otherwise, this function is high. 
• Wildlife Habitat Value and Connectivity. Upland tree groves can provide 
important habitat for terrestrial wildlife species. The size, location and 
composition of a grove are all factors influencing the quality of habitat. Larger 
groves located near or connected to other habitat areas generally provide 
greater habitat value than smaller, isolated groves. Groves with a diverse mix of 
species and structure (such as mid-canopy trees, shrubs, groundcover, and 
standing or downed logs) generally provide higher value forage, cover and 
nesting habitat than groves with few species or with no understory. 
• Level of Existing Development. Groves located on undeveloped or partially 
developed sites offer the opportunity to protect groves through site planning. 
Groves surrounded by development tend to be more at risk. 
Tree Grove Inventory Results 
Seventy STGs were identified within the City of Tigard. The majority of the groves were 
associated with Fanno and Summer Creeks and their major tributaries. The STGs range 
from 1.1 to 54.4 acres, with a combined area of 544 acres. The average STG size is 7.8 
acres and the median size is 3.8 acres; thus, several larger groves skew the average size 
upward significantly. The largest STG, Grove 67 on Bull Mountain, covers 54.4 acres. 
Most of the STGs have a mix of tree species rather than a pure stand of a single species. 
The most common identified species include: Douglas fir, ponderosa pine, western red 
cedar, bigleaf maple, red alder, Oregon ash, Oregon white oak, black cottonwood, and 
Pacific willow. 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 1. Introduction and Content 
Prepared by Winterbrook Planning 
November 2011 
City of Tigard Urban l'ore,try Code ReYi,iom I \'olume II I 232 
Page1-8 
• In areas influenced by nearby streams or wetlands, Oregon ash, red alder, 
Pacific willow, and black cottonwood are dominants, and Douglas fir and western 
red cedar are often subdominants. 
• In upland areas out of the immediate stream corridors or wetlands, dominance 
shifted to Douglas fir, bigleaf maple, and Oregon white oak, with occasional 
stands of red alder. Stands with large, open grown Oregon white oak and/or 
large ponderosa pine usually received higher scores due to the rarity of these 
features and their importance to wildlife in the Willamette Valley. 
Fifty-nine STGs (84%) are located partially or entirely within areas protected by SDC 
Chapter 17.755 Sensitive Lands. These groves are generally larger and support greater 
habitat complexity due to variation in the plant community related to moisture gradients 
between uplands and wetlands. Many of the larger STGs are within the Fan no Creek 
corridor, where the presence of parks, walking trails, and other amenities enable public 
access. 
Significance Determination 
Under the Goal 5 Rule (OAR Chapter 660, Division 23), local governments must 
inventory Goal 5 resource sites and determine their significance. Resource sites that do 
not qualify as "significant" are not subject to the ESEE decision-making process, and are 
not subject to local Goal 5 regulatory programs. 
To determine local significance, tree grove boundaries were refined to include STGs with 
contiguous canopy cover of one acre or more and to exclude linear or 
fragmented/developed areas. Winterbrook and City staff used aerial photo 
interpretation and field observation to make these determinations. 
After applying significance criteria, Winterbrook described and mapped the location, 
quality and quantity of 70 STGs shown on Map A: Significant Tigard Tree Groves and 
Impact Areas. 
Impact Area Determination 
The Goal 5 rule requires the determination of "impact areas"- or the area outside of 
significant resource sites where additional zoning regulation may be appropriate, in 
order to reduce impacts from development. The rule offers the following direction (OAR 
660-023-040): 
(3) Determine the impact area. Local governments shall determine an impact 
area for each significant resource site. The impact area shall be drawn to include 
only the area in which allowed uses could adversely affect the identified 
resource. The impact area defines the geographic limits within which to conduct 
an ESEE Analysis for the identified significant resource site. 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 1. Introduction and Content 
Prepared by Winterbrook Planning 
November 2011 
City of Tigard Urban Forestry Code Re,·isiom I Volume II I 233 
Page1-9 
Tigard has determined that the impact area for tree groves includes the properties (tax 
lots) on which STGs are located. Conflicting uses allowed within base zones could 
adversely affect the quantity and quality of inventoried tree groves as a result of root 
disturbance, drainage alteration, or construction of impervious surfaces. Partial tree 
grove removal, if improperly carried out, could damage the integrity of the remainder of 
the tree grove. 
Map A: Significant Tree Groves and Impact Areas shows the location of each of the 70 
STGs and the tax lots upon which they are located. Appendix B includes a spreadsheet 
showing impacted tax lots, both public and private, and relevant STG acreage. Overall, 
STGs cover 544 acres and impact 885 tax lots totaling 1,365 acres; thus STGs cover 
about 40% of the impacted tax lots. Most (73%) of the STGs are within Title 3 
Sensitive Lands; STGs cover 124.5 buildable acres - less than a quarter of the 544 STG 
acre total. 
The ESEE analysis in Section 3 focuses on potential impacts to Tigard's 
buildable land supply (land that is not regulated by the Title 3 provisions of 
TDC Chapter 17.775) that could result from implementation of Tigard's 
Regulatory Incentive Program. 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 1. Introduction and Content 
Prepared by Winterbrook Planning 
November 2011 
City oF Tigard Urban l'orcstry Code RcYisions I \'olumc II I 234 
Page1-10 
Section 2 - Conflicting Use and Draft Limited Protection 
{Regulatory Incentives) Program 
Introduction 
As requ ired by the Goal 5 rule, this section reviews the Tigard Development Code (TDC) 
to identify land uses and activities that potentially conflict with tree grove preservation . 
Th is review is based on (1) the base zones applicable to each STG and impact area, and 
(2) existing Title 3 Sensitive Land regulations that apply to most STGs and limit uses and 
activities otherwise permitted in the base zones. 
Methods for Identifying Conflicting Uses 
Once the tree grove inventory has been completed - and the significance of each 
resource site and its impact area determined- the next step in the Goal 5 process is to 
identify confl icting uses and activities that customarily3 are regulated by City zoning. 
The Goal 5 Rule (OAR 660-23-010) defines "conflicting use" as follows: 
(1) "Conflicting use" is a land use/ or other activity reasonably and customarily 
subject to land use regulations/ that could adversely affect a significant Goal 5 
resource * * * 
Thus, conflicting uses include the use itself plus activities customarily associated with 
the use. The Goal 5 rule also describes how conflicting uses are identified: 
(2) Identify conflicting uses. Local governments shall identify conflicting uses that 
exis~ or could occur; with regard to significant Goal 5 resource sites. To identify 
these uses/ local governments shall examine land uses allowed outright or 
conditional IV within the zones applied to the resource site and in its impact area. 
Local governments are not required to consider allowed uses that would be unlikely 
to occur in the impact area because existing permanent uses occupy the site. The 
following shall also apply in the identification of conflicting uses: (a) If no uses 
conflict with a significant resource site/ acknowledged policies and land use 
regulations may be considered sufficient to protect the resource site. 
[Emphases added.] 
3 In an urban area, there are many examples of conflicting uses that typica lly are not regu lated by zoning, but could 
adversely affect a Goals resource . For example, air pollution can adversely affect vegetation, but is typically not 
regu lated by local zoning. City zoning regu lations typically regulate where and how urban development may (or may 
not) occur on a specific site. 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 2. Conflicting Use and Draft Program 
Prepared by Winterbrook Planning 
November 2011 
City of Tigard Urban Forestry Code Rc,·isions I Volume II I 235 
Page 2-1 
This section identifies land uses and activities that conflict with full STG protection, 
based primarily on applicable base and overlay zoning districts. The primary means of 
identifying conflicting uses is by consulting the Tigard Development Code (TDC). 
Primary Tigard Development Districts (Zoning) - Uses 
The primary means of identifying conflicting uses is to first determine what zone or 
zones (including overlay districts) apply to a particular resource site, and then to identify 
uses and activities that are allowed by the zoning conflict with full protection of 
inventoried resource values. Map 8: Significant Tree Groves and Corresponding 
Comprehensive Plan Designations shows STGs in relation to plan designations (and 
implementing zoning) within the Tigard City Limits. 
Tigard's base zones are organized into four basic categories : 
• Low Density Residential (LOR), including the R-1, R-2, R-3.5 and R-4.5 
zones. In each case, the suffix refers to the average number of units per net 
residential acre in the zone. 4 Residential development in these zones is typically 
allowed through the land division and planned unit development processes, or 
through building permit review for individual lots. These zones also allow public 
and semi-public uses, such as parks and schools, through the conditional use 
process. These zones also allow streets and public facilities necessary to serve 
development. Vegetation removal, excavation and construction of new 
impervious surface areas are also allowed. 
ESEE consequences for residential development are addressed in Section 3, ESEE 
Analysis. See also discussion under Goals 5-7 (Natural Resources, Water Quality, 
and Natural Hazards) and Goal 10 (Housing). 
• Medium and High Density Residential (M-HDR), including the R-7, R-12, R-
25 and R-40 zoning districts. The suffix in these cases refers to the average 
number of units per residential acre allowed in each district. Residential 
development in these zones is typically allowed through the land division and 
planned unit development processes, or through building permit review for 
individual lots. Like the Low Density Residential zones, Medium Density 
Residential zones allow public and semi-public uses through the conditional use 
process. These zones also allow streets and public facilities necessary to serve 
development, and vegetation removal, excavation and construction of impervious 
surface areas. 
ESEE consequences for residential development are addressed in Section 3, ESEE 
4 The R-~ zone has a minimum lot size of 30,ooo square feet, t he R-2 zone ~s, ooo square feet, the R-3.5 zone ~o, ooo 
square feet, and the R-4 .5 zone ?,sao square feet . The R-7 zone a llows 8 unit s per acre, the R-12 zone ~4 units 
per acre, and the R-25 zone 29 units pe r acre . There are no STGs on land zoned R-40. 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 2. Conflicting Use and Draft Program 
Prepared by Winterbrook Planning 
November 2011 
l.ity of Tigard Urban Forestry Code Rc,·isions I \'olumc II I 2.36 
Page 2-2 
Analysis for City Limits. See discussion under Goals 5-7 (Natural Resources, 
Water Quality, Natural Hazards) and Goal 10 (Housing). 
• Mixed Use Zones (MU), including the MUE and MUR zones. The mixed use 
zones allow varying intensities of industrial, commercial, and residential uses. 
Large- scale commercial and industrial development is generally restricted in 
mixed use zones, and public facilities are allowed through the conditional use 
process. Mixed use zones include open space requirements and preservation of 
healthy, mature trees to the extent practicable. Vegetation removal and grading 
are allowed as part of the construction process. 5 
ESEE consequences for mixed use development are addressed in Chapter 5, 
ESEE Analysis for the City Limits. See discussion under Goals 5-7 (Natural 
Resources, Water Quality, Natural Hazards) and Goals 9 and 10, (Economy and 
Housing). 
• Industrial, Commercial and Office (IND-COM), including the 1-L, 1-P, C-G 
and C-P zones allow industrial uses and varying intensities of office and 
commercial uses primarily through the building permit review process, although 
land divisions or planned developments may also be required. Like the 
residential and commercial zones, streets, public facilities, vegetation removal 
and grading are allowed as part of the construction process. 
ESEE consequences for industrial, commercial and office development are 
addressed in Section 3, Tigard ESEE Analysis. See discussion under Goals 5-7 
(Natural Resources, Water Quality, Natural Hazards) and Goal 10 (Housing). 
Tigard's Existing Natural Resource Protection Program 
The Goal 5 Rule recognizes that "acknowledged policies and regulations may be 
considered sufficient to protect the resource site." Thus, Tigard's proposed Regulatory 
Incentives Program and this ESEE analysis should be seen in the context of existing 
programs that already limit conflicting uses for STGs: 
• Metro's water quality and riparian corridor functional plans (Title 3 - Water 
Quality and Flood Management and Title 13- Nature in the Neighborhoods); 
• Tualatin Basin Program recommendations and ESEE analysis for significant 
riparian corridors and wildlife habitat (which overlap considerably with STGs); 
• TDC Chapter 18.775 Sensitive Lands which implements Titles 3 and 13 and 
Tualatin Basin Program recommendations); 
• TDC Chapter 18.790 Urban Forests, which sets standards for urban forest 
management and provides regulatory incentives for preservation of existing 
trees; and 
5 There are no STGs located on land zoned MUEi there are several STGs on land zoned MUR. 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 2. Conflicting Use and Draft Program 
Prepared by Winterbrook Planning 
November 2011 
City of Tigard Urban Fore~ try Code Rc,·isions I Volume II I 23 7 
Page 2-3 
• Clean Water Services Design and Construction Standards, which includes 
standards and incentives related to improving water quality throughout the 
Tualatin River basin. 
Together, these programs provide a baseline of protection for Tigard's floodplains, steep 
slopes, wetlands, rivers, streams, and riparian corridors (including forested areas and 
wildlife habitat). 
Effect of Tigard's Regulatory Program 
As noted in Section 1 of this ESEE Analysis and as shown on Map C - Significant Tree 
Groves in Relation to Regulated (Title 3) and Non-Regulated (Title 13) Sensitive Lands, 
most of Tigard's STGs are located (partially or entirely) on land that is protected to some 
degree by TDC Chapter 18.775 Sensitive Lands. 
Chapter 18.775 implements Metro Titles 3 and 13- one of which is mandatory (Title 3) 
and one of which is not (Title 13). Accordingly, there are two levels of "Sensitive Lands" 
protection for land and water resources that are subject to: 
(1) Metro Title 3 protection through TDC Chapter 18.775; and 
(2) Metro Title 13 protection, as interpreted by Tualatin Basin Program 
recommendations, also through TDC Chapter 18.775. 
The distinction is important, because the first level of protection (Title 3) restricts most 
types of urban development; this is why land with Title 3 protection is considered 
"unbuildable" and is not included in Metro calculation regarding housing and 
employment capacity. Tigard has determined that acknowledged Sensitive Land 
regulations that implement Metro Title 3 requirements are adequate to 
protect STGs from all conflicting uses except vegetation removal. 
Title 3 Sensitive Land includes property within the 100-year floodplain, land with slopes 
of 25% or greater, natural drainageways and wetlands (including vegetative buffers). 
Tigard has 70 STGs covering 544 acres; however, 335 of the 544 inventoried tree grove 
acres (62%) already have Title 3 protection. Most urban development conflicts have 
already been resolved in favor of resource protection on Title 3 Sensitive Lands. 
In contrast, Title 13 Sensitive Land regulations offer very limited protection 
for vacant STGs that are not protected by Title 3. 
• There are a total of 124.5 vacant STG acres (23% of total STG acres); of these 
93 vacant acres have a Title 13 Sensitive Lands designation . Title 13 Sensitive 
Lands are considered "buildable" for planning purposes - unless all or part of an 
STG is dedicated to the city or protected via a restrictive covenant. 
• The remaining 32 acres (6%) of Tigard's STGs are located completely outside of 
Title 3 and 13 Sensitive Lands. 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 2. Conflicting Use and Draft Program 
Prepared by Winterbrook Planning 
November 2011 
City of Tigard Urban l:orc>try Code Rc,-i>iom I \'olumc II I 23H 
Page 2-4 
Since Tigard and CWS have limited funds for tree grove acquisition, protection of STGs 
outside of Title 3 Sensitive Land areas depends primarily on the effectiveness of Tigard's 
proposed Regulatory Incentives Program. This ESEE Analysis focuses on 
unprotected STGs outside of Title 3 Sensitive Land areas. 
Figure 2.1 shows an example of how Title 3 and 13 Sensitive Lands affect two STGs in 
Tigard. Note that the STG west of the railroad tracks is entirely within Title 3 Sensitive 
Lands or Title 13 Sensitive Lands. Note also that the STG boundary excludes developed 
residential lots. The STG east of the tracks is almost entirely within Title 13 Sensitive 
Lands. 
Figure 2.1 - Typical STG with Sensitive Lands Overlay 
l1gard sensitive Lands 
(IItle 3) 
Vegetation Removal, Grading and Construction of Impervious 
Surfaces 
Tigard Comprehensive Plan designations and primary zoning districts permit land uses 
that conflict with the full protection of STGs; the primary conflicts occur at the time of 
site preparation and construction when trees are removed. Vegetation removal, 
grading, root disturbance and construction activities can have severe adverse impacts on 
natural resource values identified in the Tigard Tree Grove Assessment and summarized 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 2. Conflicting Use and Draft Program 
Prepared by Winterbrook Planning 
November 2011 
City of Tigard Urban Forestry Code ReYisions I Volume II I 239 
Page 2-5 
on pages 1-6 and 1-7 of this report. These impacts continue when forested areas are 
paved or built upon, making re-vegetation and soil permeability unlikely. Maintaining 
multiple layers of native vegetation is an important factor in determining wildlife habitat 
significance, water quality and groundwater recharge, and scenic value. Excavation 
results in loss of vegetation, root disturbance, exposed soils and increased erosion, and 
altered drainage patterns and water courses. Impervious surface areas decrease water 
recharge, create urban "heat islands," and eliminate wildlife habitat. 
Vegetation removal and grading activities may occur independent of residential, 
commercial, industrial, park or school construction, and may not be regulated outside of 
the development review processes (e.g., design review, land divisions, planned 
developments, or building permits). Because they typically are associated with all 
conflicting land uses, vegetation removal, grading activities, and creation of impervious 
surface areas are considered as separate conflicting activities. 
Conflicting Use Matrix- by Significant Tree Grove 
Table 2.1 shows conflicting use information in another format. It is organized by 
conflicting use category as determined by the underlying zoning district, identifies STGs 
that fit within each category, and further describes conflicting uses allowed by zoning. 
This table also explains where conflicting uses are addressed in Section 3 of this ESEE 
Analysis. 
Please note that Table 2.2 on the following page recognizes that the City's existing 
Sensitive Lands regulations have a/ready limited conflicting uses identified in Table 2.1. 
Table 2.1 Summary of STG Conflicting Uses 
Conflicting STG Numbers Conflicting Use Description 
Use 
Categories 
Low Density 3, 8, 9, 10, 11 ' 12, The Low Density Residential zones permit lower 
Residential 13, 14, 17, 19, 22, density urban residential uses (1.2 to 5.8 dwelling units 
(Development 25, 32 , 33, 35, 36, per acre), including detached and attached single-
Impacts 37, 42, 45, 46, 47, family dwellings, community recreation , day care, 
Addressed 48, 49, 51 , 51a, 52, residential home and facility , minor util ities. Planned 
Under Goal 56, 56a, 59, 60, 62, Developments (reviewed through a discretionary 
10, Housing) 63, 64, 65, 68, 69, process) may allow on-site density transfers. Moderate 
73, 75, 77, 81, 83, land clearing and grading , vegetation removal , site 
86a, 91 , 93, 95, 96, maintenance; moderate impervious surfaces. 
99, 99a, 100, 101 
Medium and 2, 22 , 24, 25, 31 , 37, The Medium and High Density Residential zones High Density 42, 46, 55, 57, 59, permit urban residential uses (between 7 to 14 un its Residential 65, 67, 71 , 73, 74, per acre for Medium, 23 to 29 units per acre for (Development 75, 79, 83, 86, 86a, Medium-High , and no minimum lot size for High Impacts 89, 90, 93, 96, 97, Density), including detached and attached single-family Addressed 99, 99a, 100, 101 dwellings, community recreation , day care, residential Under Goal home and facility , minor utilities. PDs (reviewed 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 2. Conflicting Use and Draft Program 
Prepared by Winterbrook Planning 
November 2011 
City of Tigard Urban Forestry Code Rc,·isions I \ 'olume II I 24(1 
I 
Page 2-6 
Conflicting STG Numbers Conflicting Use Description 
Use 
Categories 
10, Housing) through a discretionary process) may allow on-site 
density transfers. More intensive land clearing and 
grad ing , vegetation removal , site maintenance; 
moderate-to-h igh impervious surfaces. 
Mixed Use The Mixed Use Residential zones permit medium to 
Residential high density urban residential uses, including attached 
(Development single-family dwellings, duplexes, and multi-family 
Impacts dwell ings and group homes, as well as compact 
Addressed 2, 17, 23, 24, 30, 38, commercial and industrial uses. Larger scale 
Under Goal 44, 54 commercial and industrial uses are restricted. Mixed 
10, Housing Use zones contain open space requirements and 
and Goa19, minimum floor-area ratios. PDs allow on-site density 
Economy) transfers. High land clearing and grading , vegetation 
removal , site maintenance; high impervious surfaces. 
Industrial, 3, 23, 30, 38, 40, 44, The Industrial, Office, and Commercial zones permit a 
Commercial 62, 71 , 92, 93, 97 wide range of industrial, heavy commercial , commercial 
and Office uses and related uses. Most industrial and some 
(Development commercial uses require single-story buildings with 
Impacts large areas devoted to on-site parking , resulting in 
Addressed substantial impervious surface areas, and high 
Under Goal 9, vegetation removal and site grading requirements. 
Economy) Other commercial and office uses may be developed in 
multi-story bu ildings to reduce the impacts upon 1 
surface areas. 
Public Transportation , sanitary sewer, water and storm sewer 
Facilities facil ities are necessary to serve primary conflicting 
(Development uses. Transportation facilities increase impervious 
Impacts surface area, and sometimes must be routed through 
Addressed Potentially all STGs natural resources to achieve connectivity objectives. 
Under Goal Other facilities, such as gravity flow sewer and storm 
11, Public detention facilities benefit from location near STGs, 
Facilities) wh ich often are located in riparian corridors and 
wetlands. 
Table 2.2 summarizes the STG acreage within zoning districts that allow conflicting uses 
and activities outside of Title 3 Sensitive Lands. The matrix shows four broad categories 
of conflicting uses - Low Density Residential, Medium and High Density Residential , 
Mixed Use, and Industrial-Commercial. 
Table 2.2: STG Acreage by Zoning Category 
Zone STGs Total Acres in Buildable Acres in Category STGs STGs6 
Low Density 3, 8, 9, 10, 11 , 12, 13, 14, 
Residential 17, 19, 22, 25, 32, 33, 35, 253 37 
(LOR) 36, 37, 42, 45, 46, 47, 48, 
6 Bui ldable acres consist of vacant or partially-vacant parce l area located outside of Title 3 Sensitive Lands. 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 2. Conflicting Use and Draft Program 
Prepared by Winterbrook Planning 
November 2011 
City of Tigard Urban Forestry Code Revisions I Volume II I 241 
Page 2-7 
Zone STGs Total Acres in Buildable Acres in Category STGs STGs6 
49 , 51 , 51a, 52, 56, 56a , 
59, 60, 62 , 63, 64, 65, 68, 
69, 73, 75, 77, 81 , 83, 
86a, 91 , 93, 95, 96, 99, 
99a, 100, 101 
Medium and 2, 22 , 24, 25, 31 , 37, 42 , 
High 46, 55, 57, 59, 65, 67, 71, 
Density 73, 74, 75, 79, 83, 86, 197 49.5 
Residential 86a, 89, 90, 93, 96, 97, 
(MDR-HDR) 99, 99a, 100, 101 
MU 2, 17, 23, 24, 30, 38, 44 , 19 4 54 
IND-CO 3, 23, 30, 38, 40, 44, 62 , 75 34 71 , 92 , 93, 97 
Total 544 124.5 
Source: City of Tigard GIS; Winterbrook Planning. 
As shown on Table 2.2, 86% ( 469 acres) of STGs are located in residential or mixed use 
residential zones where density transfer is permitted outright. The remaining 14% of 
STGs are located in Industrial or Commercial Zones. A total of 124.5 buildable acres are 
not protected by Title 3 Sensitive Land regulations. 
The remainder of this report will focus on the identification and resolution of 
conflicting uses on STGs that are threatened by development -that is, on the 
124.5 buildable STG acres remaining in the City. 
Chapter 3 of ESEE Analysis focuses on the economic, social, environmental and energy 
consequences of three decision options: (1) full resource protection, (2) no additional 
resource protection, and (3) providing additional but limited protection for STGs on 
buildable land through an incentive-based program. 
Chapter 4 describes the proposed regulatory incentives program and provides examples 
of how this program could work in practice. 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 2. Conflicting Use and Draft Program 
Prepared by Winterbrook Planning 
November 2011 
City of Tiganl Urban l'on:> Lry Code Rc,·isions I \'olumc II I 2-12 
Page 2-8 
Section 3 - Tigard ESEE Analysis for STGs 
Introduction 
Goal 5 requires that the economic, social, environmental, and energy (ESEE) 
consequences of three decision options be considered prior to adoption of a formal tree 
grove protection program. The ESEE Analysis is somewhat complex: it requires that 
four types of consequences (economic, social, environmental and energy) be analyzed 
for three decision options (full protection, no additional protection, and limited 
protection), for uses and activities allowed in two categories of zoning districts applied 
to STG sites (Residential and Commercial/Industrial}. 
This ESEE analysis is further complicated by the fact that the Tualatin Basin Partners 
have prepared a region-wide ESEE Analysis for "significant habitat areas"- which 
overlap considerably with STGs. Tigard applied this regional ESEE analysis when it 
adopted flexible standards for development as part of a limited protection program for 
"significant habitat areas" in 2007. 
The ESEE Analysis must be consistent with applicable Statewide Planning Goals, must 
consider public comments, and must explain why Tigard elected officials selected a 
specific tree grove protection program. 
To simplify this process, this ESEE Analysis is organized around the applicable Statewide 
Planning Goals and discusses the ESEE consequences of the three decision options in 
the context of these Goals. Chapter 3 considers the "full protection" and "no additional 
protection" options under each Statewide Planning Goal and then focuses on the ESEE 
consequences of the limited protection option: the Regulatory Incentives Program 
recommended by the CAC and described in Section 2. 
Goal 5 Rule Requirements 
OAR 660-023-040(4) requires that local governments conduct an ESEE analysis to 
determine the consequences of three regulatory options: (a) no additional resource 
protection (i.e., allow conflicting uses and activities consistent with existing regulations 
without adoption of the proposed Regulatory Incentives Program); (b) limited resource 
protection (based on the City's proposed Regulatory Incentives Program); and (c) full 
resource protection (i.e., prohibit all conflicting development and land use activities). 
(4) Analyze the ESEE consequences. Local governments shall analyze the ESEE 
consequences that could result from decisions to allow, limi~ or prohibit a conflicting 
use. The analysis may address each of the identified conflicting use~ or it may 
address a group of similar conflicting uses. A local government may conduct a single 
analysis for two or more resource sites that are within the same area or that are 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 3. Tigard ESEE Analysis 
Prepared by Winterbrook Planning 
November 2011 
Ci ty of Tigard Urban Forestry Code ReYisions I Volume II I 243 
Page 3-1 
similarly situated and subject to the same zoning. The local government may establish 
a matrix of commonly occurring conflicting uses and apply the matrix to particular 
resource sites in order to facilitate the analysis. A local government may conduct a 
single analysis for a stte containing more than one significant Goal 5 resource. The 
ESEE Analysis must consider any applicable statewide goal or acknowledged plan 
requirements/ including the requirements of Goal 5. The analyses of the ESEE 
consequences shall be adopted either as part of the plan or as a land use regulation. 
Consistent with the Goal 5 Rule, this section considers the ESEE consequences of: 
1. Full resource site (STG) protection - prohibit all conflicting uses and 
activities; 
2. No additional resource site protection (beyond that afforded by the City's 
existing Sensitive Land regulations); and 
3. Limited resource site protection (based on the Regulatory Incentives Program 
outlined in Section 2). 
Tigard ESEE Approach 
The Tigard STG ESEE Analysis is based on a three-step approach that is consistent with 
the Goal 5 Rule. 
Step 1 is to determine the overlap that exists between STGs and existing Goal 6 Water 
Quality and Goal 7 Natural Hazard protection requirements. This analysis occurs under 
the Goal 6 (Water Quality) and 7 (Natural Hazards) discussion. 
Step 2 is to analyze ESEE consequences of full protection, no additional protection, and 
limited protection for STGs within the Tigard City Limits. This City-wide approach 
correlates ESEE requirements with Statewide Planning Goal requirements, as explained 
in Subsection D, below. 
Step 3 is to analyze ESEE consequences of full protection, no additional protection and 
limited protection for STGs. In this section, we explain how the ESEE process was used 
to maintain an adequate supply of buildable land within the City Limits for employment 
and residential uses, while ensuring that property owners retain reasonable economic 
use of their property. Step 3 will justify the ultimate balancing choices made by Tigard 
decision-makers. 
Correlation among Goal5 ESEE Factors and Goals 1-15 
Table 3.1 shows the relationship between the four ESEE factors of Goal 5 and the 13 
applicable Statewide Planning Goals. The discussion following Table 3.1 elaborates on 
these relationships. 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 3. Tigard ESEE Analysis 
Prepared by Winterbrook Planning 
November 2011 
City o f Tigard Urban l;orcstry Code RcYisions I \'olumc II I 244 
Page 3-2 
Table 3.1 ESEE Consequences and the Statewide Planning Goals 1-14 
Applicable Statewide Planning Goal Economic 
ESEE Consequence 
Goal1 (Citizen Involvement) 
Document and Consider Citizen Comments 
Goal 2 (Land Use Planning) 
Adequate Factual Base 
Agency Coordination 
Consider Alternatives 
Ultimate Policy Choices 
Implementation Adequate to Carry Out 
Policies 
Goals 3 and 4 (Agricultural and Forest 
Lands) 
Goal 5 (Natural Resource Protection) 
Adequate Goal 5 Inventory 
Significance Determination 
ESEE Analysis 
3 Decision Options 
Clear and Objective Standards 
Goal 6 (Water Quality) 
Goal 7 (Natural Hazards) 
Flooding Hazard 
Steep Slopes I Sl ide and Erosion Hazards 
Goal 8 (Recreational Opportunities) 
Suitable Park Sites 
Park Development Impacts 
Goal 9 (Economic Development) 
Adequate Land Supply 
Provide Jobs 
Provide Commercial and Office Uses 
Development Impacts 
Goal10 (Housing) 
Adequate Bu ildable Land Supply 
Affordable Housing Opportun ities 
Clear and Objective Standards 
Development Impacts 
Goal1 1 (Public Facilities I Services) 
Efficient Provis ion of Urban Services 
Public Facilities Project Impacts 
Goal 12 (Transportation) 
Safe and Efficient 
Connectivity 
Multi-Modal Transportation 
Transportation Project Impacts 
Goal13 (Energy Conservation) 
Housing Near Employment 
Micro-Climate 
Public Facilities 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 3. Tigard ESEE Analys is 
Prepared by Winterbrook Planning 
November 2011 
X 
X 
NA 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Social 
X 
X 
NA 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
City of Tigard Urban Forestry Code Revisions I Volume II I 245 
Environmental 
X 
X 
NA 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
Energy 
X 
X 
NA 
X 
X 
X 
Page 3-3 
Applicable Statewide Planning Goal Economic Social Environmental Energy 
ESEE Consequence 
Transportation Connectivity X 
Compact Urban Form X 
Maximum Efficiency of Land Use X 
Goal14 (Urbanization) 
Compact Urban Growth Form X X X 
Maximum Efficiency of Land Use X X X 
Livability X X X 
Statewide Planning Goal Analysis 
As indicated in Table 3.1, Statewide Planning Goals 1-2 and 5-14 are applicable and 
addressed in this analysis. Goals 3 (Agricultural Lands) and 4 (Forest Lands) are not 
applicable because the ESEE Analysis does not address rural land outside the Metro 
Urban Growth Boundary. Goal 15 is not applicable because the Willamette River does 
not flow through Tigard. 
Goal 1: Citizen Involvement 
Goal 1 requires that the City and County actively solicit citizen input during all phases of 
the planning process, including all phases of the Goal 5 process -from the Goal 5 
inventory to adoption of regulations and incentives. As documented below, Tigard 
property owners, special interests and citizens have been actively involved in each stage 
of the Tree Grove Protection project. 
ESEE Relationship to Goal 1 
The Goal 5 administrative rule requires timely notice to landowners and opportunities for 
public involvement during the inventory and ESEE process in accordance with the 
community's acknowledged citizen involvement program.7 
History of Urban Forestry Program 
Since 2001, Tigard's citizens have been actively involved in urban forestry issues. In 
2001, the Tree Board was established to develop and administer a comprehensive tree 
management program for trees on public property. In 2006, the Heritage Tree program 
was established so that trees of landmark importance could be officially recognized and 
protected. In 2007 the Tree Board's mission was expanded to develop a "City Tree 
7 66o-023·oo6o Notice and Land Owner Involvement Loca l governments sha ll provide timely notice to landowners 
and opportunit ies for citizen invo lvement during the inventory and ESEE process. Notification and involvement of 
landowners, citizens, and public agencies should occur at the earliest possible opportunity whenever a Goa l s task is 
undertaken in the periodic review or plan amendment process. A local government sha ll com ply with its 
acknowledged citizen involvement program, with statewide goal requirements for citizen involvement and 
coordination, and with other applicable procedures in statutes, ru les, or loca l ordinances. 
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Stewardship and Urban Forest Enhancement Program" in part to ensure tree code 
revisions occurred in a comprehensive manner. In 2007 (to meet Metro Title 13 
requirements), the City adopted a "Significant Habitat Areas Map" which expanded the 
lands where tree removal permits were required. In 2008, following over a year of work 
by the Tree Board (which included a substantial public involvement effort) the 
Comprehensive Plan was amended to include an Urban Forest section. The Urban Forest 
section contains two goals to be implemented by 22 policies. Goal 2.2 Policy 11 of the 
Comprehensive Plan states, "The City shall develop and implement a citywide Urban 
Forestry Management Master Plan." 8 
In the fall of 2009 Council accepted the City's first Urban Forestry Master Plan. A 
significant emphasis of the Plan is to guide the process of making Urban Forestry Code 
Revisions (UFCR) The UFCR project proposed to update Tigard's approach to urban 
forestry regulations consistent with community expectations. The UFCR project includes 
the public involvement plan described below. 9 
Public Involvement Plan -Advisory Committees and Peer Review 
To ensure thorough and representative citizen involvement in the tree grove protection 
project, Tigard formed a 15-member Citizen Advisory Committee (CAC), composed of 
citizen stakeholders who advise staff and seek consensus solutions. The CAC has been 
meeting on tree grove protection issues since October of 2010, and has been led by an 
independent and neutral project facilitator in order to focus and manage the meetings, 
ensure meaningful input by all participants, and deal with differing views and ideas. The 
CAC is composed of representatives of the Planning Commission, Tree Board, Parks and 
Recreation Advisory Board, Transportation Advisory Committee, development interests, 
environmental interests, landscape/arborist professionals, and three citizens at large 
with technical knowledge in urban forestry issues. The CAC met 12 times from 2010-
2011. 
To ensure that the tree grove preservation project has a sound technical footing, Tigard 
formed a Technical Advisory Team (TAC). The TAC has fostered information sharing a 
forum to review technical issues brought to it by the Project Management Team, Citizen 
Advisory Committee, Peer Review Panel, and other City staff. The TAC met 11 times 
from 2010-2011. 
Tigard also created a Peer Review Panel to provide a comprehensive technical 
evaluation of the draft amendments prior to consideration by the Planning Commission 
and City Council. The function of the PRP will be to provide a professional evaluation of 
the package of code amendments and program recommendations to ensure they are 
technically sound and are likely to perform as intended. The PRP includes private and 
8 See "Tigard Urban Forestry Historical Timeline", Urban Forestry Master Plan Appendix F (City ofTigard, 2oog). 
9 UFCR Public Involvement Plan based on Public Involvement Plan for the Urban Forestry Code Revisions (City of 
Tigard, 2010) 
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public sector professionals and stakeholders with experience in urban forestry, 
. development, and natural resources. 
Public Involvement Plan - Opportunities for Participation and Information 
Over the last year, the City has hosted a series of public involvement events related to 
the tree grove inventory, protection program and ESEE analysis, including workshops 
and two open houses. These series of events were organized to inform/involve target 
participants, disseminate/reinforce project messages, and promote connections between 
project team members and stakeholders. City staff also offered presentations on the 
project to interested community groups and key stakeholders at their regular meetings. 
The Tigard City Council and Planning Commission were briefed on tree grove project 
progress in work sessions in the fall of 2010, were invited to participate in events, and 
received project materials including the newsletter. The Tigard Planning Commission and 
City Council will be holding at least one public hearing each to consider public testimony 
related to comprehensive plan and development code amendments to implement the 
Regulatory Incentives Program recommended by the CAC. 
Timely information on the Urban Forestry Code Revisions project has been posted on 
the City of Tigard's website. Website updates are announced to interested stakeholders 
through email communications. Project information has been made available in multiple 
formats: maps, flyers, factsheets, mail distribution, posters, customer counter handouts, 
and project displays. A "communications team" was designated for the project including 
the project manager. This group meets regularly to ensure successful implementation of 
the Communications/Public Involvement Plan. 
CAC Recommendations 
The CAC considered several potential "limited protection" options before recommending 
the Regulatory Incentives Program reviewed in Section 4 of this ESEE Analysis. 
Public Hearing Process 
Tigard is in the process of scheduling public hearings to review legislative amendments 
to the Tigard Comprehensive Plan and the Tigard Development Code. Through the 
public hearing process, the public will have additional opportunities to comment on the 
Tree Grove Assessment, this ESEE analysis, and the proposed Goal 5 tree grove 
protection program. 
Goal 1 Conclusion 
Because Tigard citizens have been notified and provided the opportunity to be involved 
in all phases of the Tree Grove Protection Project, the Goal 5 amendments resulting 
from this project comply with Statewide Planning Goal 1, Citizen Involvement. Citizen 
comments related to the Limited Protection Program (Draft Regulatory Incentive 
Program) will be considered through the public hearing process prior to adoption of the 
Goal 5 program the final ESEE Analysis. 
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Goal 2: Land Use Planning 
Goal 2, like Goal 5, is essentially a procedural goal. Goal 2 requires that: 
• There be an adequate factual base for making land use decisions; 
• Alternatives be considered before making ultimate policy choices; 
• Policy choices be clearly articulated in the comprehensive plan; 
• Implementation measures be consistent with and adequate to carry out such policy 
direction; and that the 
• Programs of affected public agencies be considered and accommodated to the 
extent possible. 
ESEE Relationship to Goal 2 
Factual Basis and Consideration of Alternatives 
The factual basis for the Tree Grove Project includes the Tree Grove Assessment, 
background documentation related to the selection of Draft Regulatory Incentive 
Program, and this ESEE Analysis. These documents provide City decision-makers with 
the information necessary to make informed policy decisions related to balancing 
development and STG conservation objectives. 
Regarding the consideration of alternatives, Goal 5 requires that the ESEE consequences 
of three "alternative" decision options be considered as part of the Goal 5 process. This 
ESEE Analysis considers the economic, social, environmental and energy conservation 
consequences of: 
• Fully protecting all STGs; 
• Providing no additional local protection for significant STGs (beyond existing 
sensitive land regulations); and/or 
• Providing limited protection for significant STGs outside of Title 3 Sensitive Lands, as 
specified in the Tigard UFMP and the draft Regulatory Incentive Program. 
Local Policy Choices 
The Tigard Comprehensive Plan (through the Urban Forestry Master Plan) provides clear 
direction for a limited tree grove protection program. The UFMP includes six "goals"-
with corresponding sub-goals and action measures. The UFMP's "implementation 
matrix" identifies the lead City division, cites supportive comprehensive plan policies, 
and provides information related to commitment of staff resources, relative costs, and 
timing. This background information sets the stage and policy context for the Tigard 
Tree Grove Protection Project. 
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Goal 3 of the UFMP is to "develop a tree grove protection program."10 There are two 
sub-goals: 
3.1 Focus on preserving large groves of native trees. 
3.2 Develop a flexible and incentive based grove preservation program 
that meets the needs of affected property owners. 
STGs are scenic and open space resources that must be inventoried, analyzed and 
protected consistent with Goal 5. As noted in Section 3, Tigard 's local program to 
achieve Sub-goals 3.1 and 3.2 also should be considered in the context of Metro, 
Tualatin Basin, and local planning efforts- which already provide limited tree grove 
protection in designated Sensitive Lands areas. 
Regional, State and Federal Coordination 
There is no state or federal requirement for tree grove protection per se. Goal 5 sets 
forth proceduralrequirements for inventorying and protecting tree groves that are 
addressed in this document. Although this is a local decision, it should be considered in 
the context of Metro functional planning requirements (Titles 3 and 13). 
Metro Functional Plans and Tualatin Basin Goal 5 Program 
Metro's Urban Growth Management Functional Plan (including Titles 3 and 13) has been 
acknowledged by the Oregon Land Conservation and Development Commission (LCDC) 
as complying with applicable Statewide Planning Goals- notably Goals 5, 6 and 7. 
Metro area cities and counties comply with the plan by updating their own 
comprehensive plans and land use rules to meet regional requirements. 
Metro Titles 3 and 13 address watershed health and riparian corridor management 
consistent with corresponding statewide land use planning goals. Specifically, Title 3 
addresses Goals 6 (Water Quality) and 7 (Natural Hazards), while Title 13 addresses 
Goal 5 (Natural Resources -specifically riparian corridors and wildlife habitat). There is 
considerable overlap between Title 3 and Title 13 land and water areas: e.g., land may 
be within a floodplain and support wildlife. Region-wide, 62% of the lands protected 
under Title 13's habitat designation are also protected by Title 3 water quality and 
floodplain designations. 
Title 3 - Water Quality and Flood Management 
The primary goal of Metro's Title 3 is to protect water quality and floodplain areas. 
More broadly, Title 3 reduces flood and landslide hazards, controls soil erosion and 
reduces pollution of the region 's waterways. Title 3 contains performance standards 
related to streams, rivers and wetlands to protect and enhance water quality. Title 3 
1
° Complementary goals include (1) revise the City's tree code; (2) revise the City's landscaping code; (4) develop a 
hazardous tree program; (5) improve the management of the City's urban forestry program; and (6) develop an 
urban forestry stewardshi p program . 
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establishes Water Quality Resource Areas (WQRA) along rivers, streams, and wetlands, 
and sets mandatory performance standards intended to prevent encroachment into 
forested corridors along these water bodies. The width of these WQRAs varies 
depending on the slope of the land adjacent to the water body. The WQRA width is 50 
feet generally, and 200 feet where slopes exceed 25%. The performance standards limit 
encroachment, prohibit storage of hazardous materials in water quality areas, require 
erosion and sediment control, and require planting of native vegetation on the stream 
banks when new development occurs. Title 3 also establishes and maps Flood Hazard 
Management Areas and requirements, including a regional requirement to balance cut 
and fill in areas identified on Title 3 maps. 
Notably, Metro's Title 3 (as implemented by Tigard's Sensitive Lands Chapter) restricts 
most types of urban development that would otherwise conflict with resource protection. 
Tigard has 544 STG acres of which 335 (62%) are already protected by Title 3 Sensitive 
Lands provisions. 
Title 13- Nature in the Neighborhood {Tualatin Basin Natural Places) 
Title 13 was adopted by Metro in 2005 and establishes the Nature in Neighborhoods 
program to protect, conserve and restore significant riparian corridors and wildlife 
habitat. In its summary and conclusions of the ESEE analysis for Title 13 program 
alternatives, Metro acknowledged the important role of regulatory and non-regulatory 
measures to protect important natural resources in the region. Metro observed that non-
regulatory tools have been most effective when used in conjunction with a regulatory 
program to protect important resources. 
Tualatin Basin Partners (which included eight Tualatin Basin cities, Washington County, 
THPRD and CWS) adopted regionally significant riparian corridors and wildlife habitat 
inventories prepared by Metro but conducted a separate ESEE analysis and developed a 
separate, non-regulatory program to implement Title 13. The Tualatin Basin ESEE 
analysis considered the trade-offs of allowing, limiting or prohibiting conflicting uses 
from a basin-wide perspective. 
From Metro's perspective, Title 13 areas (that lie outside of Title 3 areas) are considered 
buildable - unless acquired by a public agency or conserved through a recorded deed 
restriction. Cities are required to monitor Title 13 areas that are protected through 
acquisition or easement so that Metro can incorporate this information into its regional 
buildable lands inventory. Approximately 38% (209 acres) of Tigard's STGs are not 
protected by Title 3 Sensitive Lands provisions (of these, 84.5 acres are developed-
leaving 124.5 vacant buildable acres). Approximately 159 acres (29%) are located on 
Title 13 Sensitive Lands and the remaining 50 acres (9%) do not have a Sensitive Lands 
designation. 
Tigard 2007 TDC Amendments 
In 2007, Tigard adopted amendments to TDC Chapter 18.775 Sensitive Lands and TDC 
Chapter 18.790.040 Urban Forests to implement non-regulatory incentives (e.g./ density 
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bonuses, lot size averaging, setback and lot size reductions, and minimum density 
reductions) based on Title 13 (Tualatin Basin Program) recommendations. 11 However, 
neither of these chapters specifically restricts tree removal within significant sensitive 
habitat areas on Title 13 Sensitive Lands. 
TDC Section 18.790.040 includes limited incentives for tree retention throughout the 
community- regardless of whether a tree (or stand of trees) is located within a STG or 
not. These incentives include modest residential density bonuses; allow lot size 
averaging; permit modest lot width and depth reductions; and allow limited parking 
space and landscaping reductions for commercial, industrial and civic land uses. 
Tigard's 2011 Regulatory Incentives Program 
As noted in Section 2 of this ESEE Analysis, there is considerable overlap between STGs 
and Title 13 Sensitive Lands. Tigard's proposed limited protection program includes a 
series of regulatory incentives (density transfer, height increases, flexible setbacks, lot 
size reductions, and minimum density reductions). These provisions are consistent with 
the broad policy direction provided by (a) the Tualatin Basin Program Implementation 
Report, which was supported by (b) the Tualatin Basin Partners ESEE Analysis. Arguably, 
the 2004 Tualatin Partners ESEE Analysis covers Tigard's 2011 STG limited protection 
program. 
However, as documented in Section 4 of this ESEE Analysis (Table 18.790.1), 
the 2011 STG Regulatory Incentives Program offers much stronger and more 
effective density transfer, lot size reduction, setback reduction and height 
increase provisions than recommended by the Tualatin Basin Partners. 
Therefore, this 2011 ESEE Analysis must consider separately the consequences of 
Tigard's proposed STG Regulatory Incentives Program. 
Goal 2 Conclusion 
For the reasons stated above, the Tree Grove Assessment provides an adequate factual 
base, this ESEE Analysis demonstrates that alternative programs were considered and 
that regional programs have been considered, and the UFMA provides ultimate policy 
direction that is implemented consistently and effectively by the proposed Regulatory 
Incentives Program. For these reasons, the Tigard Tree Grove Project complies with 
Statewide Planning Goal 2, Land Use Planning. 
11 See Tualatin Basin Program Implementation Report, pp. 52-68 and 104-109. 
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Goal 5: Natural Resources 
Goal 5 reads (in relevant part) as follows: 
To protect natural resources and conserve scenic and historic areas 
and open spaces. 
Local governments shall adopt programs that will protect natural resources and 
conserve scenic, historic and open space resources for present and future generations. 
These resources promote a healthy environment and natural landscape that 
contributes to Oregon s livability. * * * 
Following procedures, standards, and definitions contained in commission rules, local 
governments shall determine significant sites for inventoried resources and develop 
programs to achieve the goal. 
Goal 5 is largely procedural in nature: it requires that certain steps be followed before 
making a decision regarding the level of protection that should be afforded to significant 
Goal 5 resource sites. It sets forth a process for resolving conflicts between natural 
resource preservation on the one hand, and urban development on the other. Goal 5 
does not mandate "protection" of significant natural resource sites as that term is 
commonly used. Rather, as explained in the Goal 5 Rule (OAR Chapter 660, Division 
23), '"protect' means to develop a program consistent with this division." 
As required by the Goal 5 Rule, the Tree Grove Assessment is a valid Goal 5 inventory 
showing the location, quantity, and quality of STG sites within the Tigard City Limits. 
The Goal 5 Inventory is shown on Map A. The location, quantity and quantity of STGs 
are summarized in Section 1 of this ESEE Analysis. 
The Goal 5 Rule also requires that uses (i.e., land uses and related activities) that 
conflict with the full protection of significant Goal 5 resource sites be identified. Section 
2, Conflicting Use Identification, describes conflicting uses (i.e., permitted and 
conditional uses allowed by applicable zoning districts) that are allowed by the Tigard 
Comprehensive Plan and Development Code. The primary conflicting activities resulting 
from permitted and conditional uses are vegetation removal and excavation that impacts 
root systems, which typically occur during the site preparation phase of an approved 
development, but potentially could occur at any time. Tigard's proposed land use 
regulations "limit" these activities by offering incentives to minimize impacts on STGs as 
described in the Regulatory Incentive Program. 
Finally, the Goal 5 Rule requires that local governments make a "decision" regarding the 
level of protection that should be afforded significant Goal 5 resource sites - but only 
after conducting an ESEE analysis. Section 1 describes the three program options 
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available to Tigard (full resource protection, no resource protection and limited resource 
protection). Section 4 includes an outline the Regulatory Incentive Program (limited 
protection option) selected by CAC. This section discusses the ESEE consequences and 
Statewide Planning Goal implications of the three decision options for the City Limits as 
a whole. 
ESEE Relationship to Goal 5 Significant Resource Sites 
This section focuses on the environmental and social consequences of the three Goal 5 
decision options. 
Economic consequences are considered under the discussion of other goals - especially 
Goals 9 (Economy), 10 (Housing), 11 (Public Facilities) and 12 (Transportation). That 
discussion addresses the economic consequences of full and no additional protection 
options on two general conflicting use categories: commercial/industrial (Goal 9), 
residential (Goal 10), and public facilities (Goals 11 and 12). The economic value of 
STGs includes enhanced property values, reduced stormwater management costs, 
carbon sequestration, and reduced energy costs. Economic costs include tree grove 
maintenance costs. The discussion of energy consequences is consolidated under Goal 
13, Energy Conservation. 
Environmental and Social Consequences of Full and No Additional 
Protection Options for Land without Natural Hazards 
As noted under the Goal 6 and 7 discussions that follow, STGs offer substantial 
environmental and social benefits by helping to maintain air, water, and land resource 
quality and by mitigating natural hazards. The discussion below focuses on additional 
environmental and social consequences that would result from the full protection and no 
additional protection options. 
Environmental Consequences 
STGs provide a variety of independent ecological functions which are summarized 
below: 
• Air quality benefits: addressed under Goal 6; 
• Hydrological water quality and stormwater management benefits (addressed 
under Goals 6 and 7; 
• Microclimate amelioration benefits: addressed under Goal 13; and 
• Wildlife habitat and carbon sequestration benefits: addressed below. 
Significant Wildlife Habitat Benefits 
The Tigard Tree Grove Assessment explicitly inventories and ranks STGs according to 
their wildlife habitat function. STGs provide food and shelter for urban fauna. Most 
STGs are within or adjacent to riparian corridors that are part of a regional wildlife 
habitat system (e.g., Fan no Creek and the Tualatin River). Thus, STGs provide habitat 
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for wildlife, supplying food, water, and cover for a variety of urban fauna, such as deer, 
squirrels, and birds.12 
As documented in the Tree Grove Assessment, STGs vary in their potential habitat value 
depending on the size, structure, and connectedness of the resource site. Healthy 
forests of large size, high connectivity and/or high structural complexity (mixed herb, 
shrub and tree layers) generally provide greater habitat values than other resource sites. 
Resource sites located along riparian corridors or linked to larger upland habitats provide 
important opportunities for wildlife migration in Tigard. 
The full protection option would prohibit all land uses and activities that conflict with 
(i.e., reduce the integrity of) wildlife habitat values documented in the Tigard Tree 
Grove Assessment, which is incorporated into this ESEE Analysis by reference. Full 
protection of significant STGs would reinforce connections with regional wildlife habitat 
systems. 
Conversely, the no additional protection option would have negative environmental 
consequences, because regulatory incentives would not be adopted to encourage STG 
preservation, making it more likely that conflicting urban uses and activities identified in 
the Tree Grove Assessment would occur. Without effective regulatory incentives, it is 
highly probable that the environmental values outlined above, and discussed in greater 
detail in the Tigard Tree Grove Assessment, would be lost. 
Socia/ Consequences 
The social consequences of the full protection and no additional protection options are 
mixed. 
On the one hand, the Tigard Comprehensive Plan recognizes the importance of tree 
groves to the quality of life of area residents. Tigard's STGs have matured over the 
course of many years as the Tigard community itself has grown. The City's urban 
forests are critically important to the quality of its urban fabric. They define residential 
neighborhoods and form the backdrop for commercial and industrial developments. 
On the other hand, full protection would prohibit many socially-beneficial uses that are 
currently allowed within Sensitive Land areas, such as public facilities and water-
dependent uses. 
Social benefits resulting from the full protection option (but would be foregone in the no 
additional protection option) include: 
12 See also Oregon Tree Guide: Benefits/ Costs and Strategic Planting (McPherson, Maco, 
Peper, Xiao, VanDerZanden and Bell, International Society of Arboriculture, Pacific 
Northwest Chapter, 2002). 
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• Aesthetic and scenic values 
• Health benefits 
• Recreational and educational values 
• Public safety and welfare 
• Screening and buffering 
• Noise attenuation 
Aesthetic and Scenic Values 
Tigard's urban forests are an important part of the community's identity and help to 
shape and define individual neighborhoods within the City, creating a sense of place. 
The City's riparian corridors and associated STGs convey a distinctive character and 
aesthetic value to residential neighborhoods and to the quality of life of their residents. 
They enhance the appearance of the built environment and in some cases serve as local 
landmarks, uniquely distinguishing a neighborhood or place. 
Tigard takes urban forestry seriously and is justifiably proud to be recognized as a "Tree 
City USA". Recent amendments to the comprehensive plan call for protection of tree 
groves - while respecting individual property rights and encouraging appropriate urban 
infill. The City's Urban Forestry Master Plan (UFMP, November 2009) underscores 
Tigard's commitment to the comprehensive management of Tigard's 1,853 acres of 
existing tree canopy through a variety of methods - including incentives-based 
protection for STGs. 
Research has shown that the public appreciates the connection between trees and the 
aesthetic quality of their communities. In one study, the majority of residents reported 
damage to trees as the single greatest loss sustained by their communities in the 
aftermath of a major storm that caused widespread damage to homes and property 
(Hull 1992). 
Stress Reduction and Health Benefits 
STGs are known to have immediate and lasting physical and psychological health 
benefits. As discussed above, trees improve air quality and remove pollutants such as 
nitrogen dioxide, carbon monoxide, sulfur dioxide, ozone, and airborne particulates. 
Every year trees in Tigard purify the air and remove enough pollutants to provide 
substantial savings in health care and associated costs (American Forests 2001). 
While improving air quality and reducing related respiratory illnesses, riparian and 
upland tree groves can also significantly reduce stress for people who live close to them. 
Researchers have shown that brief encounters with trees and natural environments can 
reduce stress and aid cognitive fatigue recovery, improving a person's capacity to 
concentrate (Kaplan and Kaplan 1989). Similarly, other researchers have found that 
people who view trees and natural environments after stressful situations show reduced 
physiological stress response, as well as better interest and attention and decreased 
feelings of fear and anger or aggression (Ulrich et al. 1994). Related studies by Ulrich 
have shown that driving along scenic roads reduced driver stress and had an 
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"inoculation" effect in which drivers responded more calmly to stressful situations 
(Aronson 2003). 
Forested areas have been credited with reducing aggression and violence in cities and 
encouraging positive social behavior. Crime reduction can be a major benefit of trees 
planted in urban neighborhoods (Sullivan and Kuo 1996). Researchers also found that 
children who could see urban forests from their windows were better able to 
concentrate and to control impulsive behavior. In general, trees afforded a place for 
neighbors to meet and get to know each other - a place where friendships developed 
into a network of support for the residential community. 
In a study of recuperation rates after surgery (Ulrich 1984) found that patients 
recovering from surgery recovered more quickly and needed fewer painkillers if they had 
a view of trees from their hospital bed. Therapists are now using trees and other plants 
to help people with physical and mental problems. 
As discussed under Economic Consequences, visual contact with nature can also 
improve office worker productivity and job satisfaction, which has important health 
implications. Office workers with a view of trees and greenery reported better overall 
health, and had a significantly lower incidence of illness (Kaplan and Kaplan 1989). 
Recreational and Educational Values 
Tigard's extensive system of public parks and open space areas include substantial 
forested areas. STGs on private lands can also provide neighborhood recreational and 
educational benefits. Trees greatly contribute to the recreational experience by bringing 
aesthetic, scenic, and natural qualities to the settings people select for outdoor leisure. 
They make these places more comfortable by providing shade and moderating local 
climate conditions. 
Forested riparian and upland wildlife habitat areas offer an immediate connection to 
nature within an urban area, in parks, as protected private open space, and in back 
yards. This can be especially important to children or people with limited mobility who 
otherwise have little contact with nature. People appreciate the value that forested 
areas add to the recreational experience: a survey of park users found a strong 
preference for a mostly wooded recreational site versus a grassy but sparsely treed site 
(Dwyer et al.1989). 
STGs also attract birds and urban wildlife. Wildlife viewing is a popular activity among 
metropolitan area residents and visitors. (Houck and Cody, eds. 2000) Wildlife viewing 
has increased steadily since 1980, when a nationwide survey of wildlife-related 
recreation found that 55% of respondents interact with wildlife near their homes by 
watching, feeding, photographing, or painting them (Shaw et al. 1985). In Seattle, a 
survey found that 90% of park-users reported that the presence of wildlife enhanced 
their recreational experience of the park (Dick and Hendee 1986). 
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Public Safety and Welfare 
Trees play an important role in protecting communities from risks associated with 
natural hazards such as landslides and flooding. (See Goal 7 discussion.) Trees are 
important to maintaining stable slopes and "perform a major engineering role in 
protecting the landscape" (Morgan and Rickson 1995). Trees and other vegetation help 
stabilize slopes by absorbing water via roots and transpiring it back into the atmosphere 
through leaves, by increasing the penetration of water into the soil and thereby reducing 
surface erosion, and by providing a root system that increases the physical cohesion of 
the soil mass, both vertically and horizontally (Coppin and Richards 1990). Many of the 
landslides that occurred during the winter of 1996 in the Portland metropolitan area 
involved slopes that had previously had trees removed. 
Outside of areas already protection by Title 3 Sensitive Land regulations, healthy urban 
forests can also reduce flood-related injuries and property damages. Urban trees can 
reduce peak storm runoff by as much as 20% through water absorption and 
evapotranspiration and significantly reduce the risk of floods (Boykin 2003). 
Screening and Buffering 
STGs can act as an "edge" between different land uses, creating visual buffers, for 
example, between business and residential areas. This vegetation can also help to 
establish community character as noted previously and can help unify developments or 
neighborhoods, just as they can be used to separate and create buffers. 
At a smaller scale, urban forests can screen unattractive areas and objects, and can 
serve to soften and buffer structures and parking lots. Trees also can be used to create 
privacy for individual homeowners, such as provided by riparian vegetation along a 
property line. 
Noise Attenuation 
Noise in urban areas can reach unhealthy levels: some construction processes, for 
example, can produce noise exceeding 100 decibels, which is considered high intensity 
noise that can be very damaging, even in very short durations. Urban forests can form 
a barrier that partially deadens the sound from traffic, manufacturing processes, 
construction activities, and other loud noises. STGs reduce sound directly by reflecting 
and absorbing its energy. For example, a 100-foot-wide tree buffer has been shown to 
be capable of reducing noise levels by 6 to 8 dba (Leonard and Parr 1970). Trees also 
can mask some noise with the sound of their rustling leaves and wind through the 
branches (Harris 1992). STGs can absorb more high frequency than low frequency 
noise, an added benefit since higher frequencies are most distressing to people (Miller 
1997). 
Social Costs (Adverse Social Consequences) 
Full protection of natural resource areas in an urban context has counter-balancing 
social costs. In contrast, if Tigard were to maintain existing regulations (the no 
City of Tigard Urban Forestry Project 
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additional protection option) then the community would not incur these adverse social 
costs. 
Adverse social consequences associated with the full protection option include: 
• Social Equity- the view that property owners should not bear the full burden of 
maintaining STGs solely because they had been good stewards of the land in the 
past.13 
• Urban Wildfires- Full protection can endanger homes and businesses at the edge 
of areas with significant and combustible vegetation. There could be adverse 
social impacts associated with unprotected homes at the edge of fully protected 
areas. (See Goal 7 ESEE discussion.) 
• Recreational Activities- full protection of all significant resource areas could 
prohibit even passive recreational uses and activities, such as trail construction or 
picnic areas. Such uses and activities have enormous social value for area 
residents. (See Goal 8 ESEE discussion.) 
• Employment Opportunities- In limited circumstances (e.g., industrial and 
commercial areas) -full protection of STGs would marginally decrease the supply 
of development-ready industrial land necessary for basic employment 
opportunities. Loss of such jobs could have adverse social consequences for the 
community. (See Goal 9 ESEE discussion.) 
• Affordable Housing- The provision of affordable housing is critically important to 
maintaining to meeting Tigard's housing and employment goals. Protection of all 
STGs - with concomitant density transfer - could reduce the City's residential 
buildable land area and therefore would further increase housing costs for existing 
and future residents. (See Goal 10 ESEE discussion.) 
• Efficient Use of Scarce Public Resources- Tigard decision-makers have a fiduciary 
responsibility to their constituents to use public monies wisely. The full protection 
option could increase the costs of providing public infrastructure and therefore 
would have adverse long-term social consequences for existing and future 
community residents. Maintaining continued confidence in the ability of City 
elected officials is also a governance issue: the community's long-term ability to 
work together to solve environmental, social, economic and energy problems 
depends in significant part on the confidence that the citizenry places in local 
elected officials. (See Goal 11 and 12 ESEE discussions.) 
• Premature Loss of Rural Open Space- Inefficient use of land within the Tigard City 
Limits will result in premature conversion of farm and forest land to urban uses to 
meet urban growth needs. There are enormous social benefits for Tigard area 
residents associated with maintaining such rural lands. (See Goal 14 ESEE 
discussion.) 
13 Social equity issues repeatedly were raised in public workshops and hearings before the CAC. The issue of fairness 
to property owners who had maintained forested areas for years in anticipation of eventual urban development 
was a major consideration for CAC members. Evidence of social equity concerns is found in the minutes of public 
workshops held by the CAC from October 2010 through June 2011. 
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Full protection of STGs could have other minor social costs. Pollen from vegetation 
causes allergies for some people. Citizens may incur costs associated with allergy relief 
and medication. Another social issue relates to safety and defensible space. Forested 
areas with understory vegetation can be a safety concern for local communities. In 
Tigard, however, forested areas with dense understory vegetation are uncommon, and 
are generally located at a distance from populated areas. In Tigard's STGs, trail systems 
and recreational facilities will be designed with careful attention to public safety issues. 
In contrast, the no additional local protection option would avoid both the social costs 
and benefits that could result from full STG protection. The no additional protection 
option would be inconsistent with the social values expressed in the Tigard UFMP. The 
no additional local protection option would result in further degradation to air, land, and 
water resources quality- with corresponding adverse social consequences. Allowing 
conflicting uses fully without protection incentives for STGs would result in the loss or 
degradation of one of the defining characteristics of Tigard neighborhoods, eroding the 
City's visual quality and livability. Health benefits (with the exception of allergies), 
recreational and educational values, screening and buffering, and noise attenuation 
values also would be lost or degraded. Tigard residents place a high premium on 
environmental values. If such values are not conserved in a balanced manner, public 
trust in elected officials and in local government would be compromised. 
Environmental and Social Consequences of Limited Protection Program 
The Regulatory Incentives Program has the potential to achieve the environmental and 
social benefits of the full protection program, while avoiding most of the negative 
consequences of the no additional protection option. 
• Approximately 86.5 of the 124.5 buildable acres with STGs are designated for 
residential use (or mixed use) and are therefore eligible for density transfer 
under proposed TDC amendments - thus providing the opportunity to avoid 
most of the negative consequences that could result from full protection. In the 
Goal 10 Housing discussion, Winterbrook estimates that approximately half of 
these 90 acres will be protected - without loss of residential density - as a result 
of the Regulatory incentives program. 
• Some 34 of the 124.5 buildable acres with STGs are designated for commercial 
or industrial use- where density transfer is unlikely. In the Goal 9 Economic 
Development discussion, Winterbrook estimates that the Regulatory Incentives 
Program will protect relatively little buildable employment land - so that the 
social benefits (jobs) resulting from efficient use of Tigard's limited supply of 
employment land are unlikely to be adversely affected. 
The density transfer provisions of the Regulatory Incentives Program will allow for 
strategic placement of public facilities necessary to serve development and 
transportation improvements necessary to connect development in Tigard . By allowing 
for removal of dead and diseased trees the likelihood of wild fires will be reduced. 
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In summary, the Regulatory Incentives Program represents a creative balance that 
avoids many of the adverse environmental and social problems associated with the two 
extremes discussed above. The limited protection program provides incentives for 
protection of all or part of 70 STGs through effective density transfer and setback 
reduction provisions. The limited protection program allows for public infrastructure and 
similar relatively low-impact uses that provide substantial public benefits without a 
corresponding loss of environmental value. 
Goal 5 Conclusion 
The proposed Regulatory Incentives Program (limited protection program) maintains 
most of the environmental values described in the Tree Grove Assessment without 
sacrificing important social values associated with social equity, wildfire protection, park 
development, industrial employment opportunities, affordable housing, the efficient 
provision of public facilities and services, and compact urban growth form. As a result 
of this ESEE Analysis the proposed Regulatory Incentives Program would provide limited 
protection for STGs with buildable land outside of Title 3 Sensitive Lands areas -
approximately 23% (124.5 acres) of the STGs within the Tigard City Limits. 
City of Tigard Urban Forestry Project 
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Goal 6: Air, Land and Water Resource Quality 
Statewide Planning Goal 6 requires that cities adopt policies and implementation 
measures to ensure that air, land, and water quality are not "degraded" and that state 
and federal environmental quality standards are met. Statewide Planning Goal 6 is 
implemented on a regional basis by Metro Title 3 and CWS regulations. Metro Title 3 is 
implemented by CWS and by the City through Chapter 18.775, Sensitive Lands. 
ESEE Relationship to Goal 6 
Tualatin Basin Partnership communities, in coordination with CWS, have adopted several 
programs to achieve the purposes of Goal 6 throughout the Tualatin River Basin, 
including: 
• Stormwater Master Plans 
• Erosion Control regulations 
• Pollution Control regulations 
The proposed Regulatory Incentives Program does not apply to land that is not already 
protected by Title 3 Sensitive Lands regulations. Nevertheless, protection of STGs (both 
within and outside of Title 3 Sensitive Land areas) helps to maintain air, land, and water 
resource quality by reducing the impacts from urban development. Conversely, if STGs 
are not protected, there are adverse consequences for air, land and water resource 
quality. 
The Goal 5 administrative rule (OAR 66-023-0240) states that Goal 5 procedural 
requirements do not apply to measures that implement Goal 6, provided that such 
measures do not "exceed" the requirements of these goals. 
(1) The requirements of Goal 5 do not apply to the adoption of measures 
required by Goals 6 and 7. Howeve~ to the extent that such measures exceed 
the requirements of Goals 6 or 7 and affect a Goal 5 resource site/ the local 
government shall follow all applicable steps of the Goal 5 process. 
ESEE Consequences of Full and No Protection Options for Air, Land, and 
Water Resource Quality 
This section considers environmental, economic and social consequences of fully 
protecting STGs (including those with limited Title 3 protection) and of not providing 
additional protection for STGs (allowing conflicting uses fully outside of Title 3 Sensitive 
Lands). Energy consequences are addressed under Goal 13, Energy Conservation. 
During this discussion, it is important to remember that Tigard must comply with 
regional, state and federal water and environmental quality regulations in any case. 
Therefore, the no additional protection option retains existing local and state regulatory 
protection for air, land, and water resources. However, the no additional protection 
City of Tigard Urban Forestry Project 
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option means the loss of additional benefits provided by STGs (outside of Title 3 
Sensitive Lands) for air, land, and water resources quality. 
Title 3, as implemented through Tigard's Sensitive Land regulations, already provides 
limited protection for streams, wetlands, floodplains, steep slopes, and their "Vegetated 
Corridors" (water quality setback areas) from most types of development, thereby 
providing benefits for air, land, and water resources quality. However, new public 
utilities and transportation facilities are permitted within Vegetated Corridors. (TDC 
18. 775.090) 
Thus for Goal 6 purposes: 
• The full protection option would prohibit new public utilities and transportation 
facilities within Title 3 Vegetated Corridors and would prohibit all tree removal 
and other development within STGs outside of such corridors. 
• The no additional protection option would continue to allow public utilities and 
transportation facilities within Vegetated Corridors subject to local review and 
mitigation but would do nothing to protect STGs outside Title 3 Sensitive Lands 
areas. 
• The proposed limited protection program would not change existing Title 3 
regulations but would provide incentives for protecting approximately 124.5 
acres of buildable land within STGs that outside of Title 3 Sensitive Land areas. 
Environmental Consequences 
Under the full protection option STGs within Vegetated Corridors would be fully 
protected. Vegetated riparian setback areas can enhance water quality in many ways. 
Undisturbed densely-forested riparian corridors trap sediments, inhibit erosion, and filter 
runoff originating from impervious surfaces, lawns, golf courses, and the like. 
Sedimentation and erosion, although ~natural processes, are accelerated in urban areas 
by increased impervious surfaces. Impervious surfaces also inhibit infiltration. Sediment 
within a riparian corridor can be from erosion of poorly forested uplands, runoff from 
impervious surfaces, or floods from an adjacent water resource. Sediments often carry 
nutrients (e.g. phosphates and nitrates) and pollutants (e.g. heavy metals, 
hydrocarbons) to water resources, altering water chemistry, burying spawning gravels 
and impacting fish and wildlife habitat. Excessive concentration of nutrients in the water 
can trigger algal blooms, depleting the water of oxygen required by fish and other 
aquatic organisms. The ability of a riparian corridor to resist erosion is related to slope, 
soil type, type of vegetation, vegetation cover, landscape position, and degree of human 
disturbance. 
STGs within Vegetated Corridors also provide a valuable flood management function by 
reducing the force and volume of floodwaters. Floodwaters flowing into a forested, 
flood-prone riparian corridor can be slowed or temporarily stored, reducing peak flows 
and downstream flooding. Woody vegetation, in particular, resists floodwaters and 
reduces its velocity. Topographic features such as swales and depressions can enhance 
a riparian corridor's ability to manage flood flows. Reducing the velocity of floodwaters 
City of Tigard Urban Forestry Project 
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in the riparian corridor allows infiltration of water into the soil. Water entering the soil is 
slowly released into the main channel, delaying its movement downstream. 
STGs that provide shade near streams and wetlands can reduce water temperature. 
Water temperature affects the ability of a stream to support viable populations of certain 
aquatic organisms. Riparian shade, especially forest canopy, moderates temperature 
within and adjacent to a water resource. Although stream temperatures are important 
throughout the year, summer temperature is generally more critical for fish species such 
as salmon ids. High water temperatures and sunlight are factors that can promote algal 
blooms, reducing dissolved oxygen required by anadromous fish and other cold-water 
dependent organisms. The aspect or orientation of the water resource and the height of 
the adjacent riparian vegetation play important roles in how effective riparian vegetation 
is in providing shade. 
STGs regardless of their location can help protect soil and improve water and air quality. 
Trees and other plants hold soils in place during rain and wind. Land with steep slopes 
is especially susceptible to erosion. STGs also helps keep sediment and contaminants 
from entering water bodies. Trees slow stormwater runoff, thereby minimizing erosion 
and allowing the ground to filter out sediments and nutrients as the water soaks down 
into groundwater reserves or passes into streams. Since some of Tigard's STGs are 
located on hillsides, retention of STGs in hillside areas has positive consequences for 
land and water quality. STGs also improve air quality by removing carbon dioxide from 
the air and replenishing it with oxygen. These effects are more noticeable in developed 
areas, where environmental quality is more degraded. 
Poor air quality is both a human and an environmental concern: air that is polluted and 
high in temperatures can degrade ecological functions and damage the health of local 
plant and animal communities. Trees within Tigard's STGs remove pollutants such as 
nitrogen dioxide, carbon monoxide, sulfur dioxide, ozone, and airborne particulates. 
Trees also help reduce wind speed so that heavy particles settle out. STGs naturally 
absorb carbon dioxide, storing carbon as they grow, helping to reduce the effects of 
global warming which can cause widespread damage to ecological communities. The 
average urban tree, for example, removes nearly a ton of greenhouse gas during its first 
40 years of life (Boykin 2003). 
STGs also help conserve soils and stabilize slopes, thus maintaining land quality. Fibrous 
root systems hold soil in place, reducing erosion caused by wind, rain, and surface 
runoff. Tree branches and leaves reduce the impact of rain on the soil. Leaves fall to 
the ground, decompose, and provide nutrients to the soil. By binding soils, dissipating 
erosive forces, and providing nutrients, trees protect and enhance the diversity and 
abundance of soil organisms. In the same manner, trees and their root systems help to 
hold and protect steep slopes from erosion and failure. Tree roots reinforce the soil, 
increasing soil shear strength, and bind soil particles, reducing their susceptibility to 
erosion. 
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Full local protection of STGs has clear benefits for air, land, and water quality. To the 
extent that STGs are removed for public utility and transportation facilities within 
Vegetated Corridors, some of the benefits described above can be lost. Tree removal 
within STGs generally will have significant adverse affects on air, land and water 
resource quality. 
Conversely, if conflicting uses were allowed fully on STGs outside of Title 3 Sensitive 
Lands areas (no additional local protection), then approximately 124.5 STG acres would 
be lost to conflicting uses - which would have adverse environmental impacts on air, 
land, and water quality within the Tigard City Limits. 
Economic and Social Consequences 
Compliance with state and federal environmental standards can be costly for local 
governments. However, by fully protecting all STGs, the costs of meeting water and air 
quality standards can be mitigated. 
For example, American Forests developed the CTIYgreen 5.0 model in 2003 to calculate 
the amount of air pollutants removed per unit of forested area in cities throughout the 
United States. Based on results from the Seattle airshed, urban trees provided the 
following avoided cost results (in 2002 dollars): 
• $970 per ton of carbon monoxide; 
• $1,653 per ton of S02; 
• $4,519 per ton of particulate matter (PM10); and 
• $6,768 per ton of volatile organic compounds and ozone. 
Similar values were reported in reports prepared by the California Energy Commission 
(1992) and the US Office of Management and Budget (2003). 
Although the 544 acres covered by Tigard's STGs represent a small portion of Tigard's 
tree canopy cover, full protection of Tigard's STGs would nevertheless provide 
substantial health benefits to existing and future Tigard residents. 
Tigard's adopted stormwater master plan also recognizes the benefits natural areas 
provide for on-site stormwater management. When stormwater is treated at the source 
by saving trees or reducing pavement, then stormwater infrastructure requirements are 
correspondingly reduced. Costs for compliance with National Marine Fisheries Service 
(NMFS) requirements related to water quality and temperature can also be reduced. 
In Tigard (as in other metropolitan cities), protection of STGs can reduce infrastructure 
construction costs, and improve long-term community relations -all of which make 
good economic sense. The message is clear: there are economic benefits associated 
with full protection of STGs in Tigard. 
On the other hand, full protection of STGs may not be the most cost-effective way to 
achieve environmental standards. For reasons stated in the Goal 8-12 discussion, full 
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November 2011 
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protection of all STGs would likely result in decreased efficiency of land use, and 
resultant increases in land acquisition and development costs for parks, businesses, 
housing, public facilities and transportation projects. Full protection could also increase 
out-of-direction travel, with attendant adverse air quality impacts. 
In conclusion, there are substantial positive socia l and economic consequences - in 
terms of reduced costs for meeting local, state and federal environmental standards -
associated with the full resource protection option. However, these costs need to be 
weighed against urban land acquisition and development costs that are addressed in 
other sections of this ESEE Analysis. 
IfTigard were to allow conflicting uses fully, the costs for meeting state and federal 
environmental standards would likely increase substantially, along with increased 
infrastructure construction and maintenance costs. Reliance on "after the fact" hard 
engineering methods of pollution control can have substantial dollar costs that need to 
be considered when determining the economic consequences of allowing unrestricted 
development (i.e., allowing conflicting uses fully). On the other hand, there would be 
no restrictions on development or placement of public utilities and transportation 
facilities, which would increase land use efficiency. 
ESEE Consequences of Limited Protection Program for Air, Land and 
Water Resource Quality 
The proposed Tree Grove Regulatory Incentives Program, when combined with existing 
Title 3 Sensitive Land and CWS regulatory programs, provides a high level of protection 
for STGs. 
Environmental Consequences 
Tigard 's limited protection program should be viewed in the context of existing state, 
regional and local programs to maintain and enhance air, land and water resources 
quality by strategically protecting urban forests. Although the proposed Regulatory 
Incentives Program does not have all of the environmental benefits that would accrue 
from full resource protection, the limited protection program has only marginal adverse 
environmental consequences for air, land, and water resource quality. 
Although limited conflicting uses are permitted within Title 3 Sensitive Land areas, the 
335 STG acres that now have Title 3 protection are not seriously threatened by 
permitted uses and activities. Moreover, about 73% of the 124.5 buildable STG acres 
that do not have Title 3 Sensitive Lands protection are designated for residential use-
and therefore stand to benefit from clear, objective and effective density transfer 
provisions of the Regulatory Incentives Program. 
Economic and Social Consequences 
To the extent that property owners take advantage of proposed density transfer and 
dimensional adjustments available through the proposed Chapter 17.090.050 incentives, 
City of Tigard Urban Forestry Project 
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the economic and social consequences of the Regulatory Incentives Program are 
. positive, because they will have the effect of reducing public and private stormwater 
collection and treatment costs and reducing health care costs associated with air 
pollution. (See discussion under full protection option.) 
Goal 6 Conclusion 
Both the full protection option and the proposed limited protection program complement 
existing City, County, and State air, land, and water resource quality programs. When 
compared with the no additional protection option, both the full and limited protection 
programs have substantial positive ESEE consequences. 
City of Tigard Urban Forestry Project 
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Goal 7: Natural Hazards 
Goal 7 reads (in relevant part) as follows: 
To protect people and property from natural hazards. 
A. Natural Hazard Planning 
1. Local governments shall adopt comprehensive plans (inventories/ policies and 
implementing measures) to reduce risk to people and property from natural 
hazards. 
2. Natural hazards for purposes of this goal are: floods (coastal and riverine)/ 
landslides/ earthquakes and related hazard~ tsunamis/ coastal erosion and 
wildfires. Local governments may identify and plan for other natural hazards. 
Natural Hazard Protection and Effect on ESEE Analysis 
TDC Chapter 18.775, Sensitive Lands resolves most (but not all) conflicts between 
development and STG preservation in Title 3 hazard areas (areas within the 100-year 
floodplain and with slopes of 25% or greater). Chapter 18.775 allows for limited private 
and public land uses and activities within hazard areas. For example, replacement of 
existing structures, construction of water dependent and related uses, removal of 
hazardous trees, construction of transportation and utility facilities, and construction of 
flood management facilities are permitted in Title 3 Sensitive Lands subject to locational 
and construction standards. 
Metro and the City of Tigard consider such hazard areas "unbuildable" for purposes of 
meeting housing and employment needs. Because these protected hazard areas are 
unbuildable for most urban uses, the ESEE consequences of allowing, prohibiting or 
limiting conflicting uses are different for mapped hazard areas than for otherwise 
buildable areas. 
ESEE Relationship to Goal 7 
Most of Tigard's STGs are located in areas with Title 3 Sensitive Lands protection: 
• 55 of 70 STGs (79%) are protected (at least partially) by Title 3 Sensitive Land 
regulations; and 
• 335 of 544 STG acres (62%) are protected by Title 3 Sensitive Land regulations. 
In considering this relationship, Metro and Tigard officials have already determined that 
protecting STGs in Title 3 natural hazard areas (where most types of development are 
already prohibited) generally has positive economic, social, and environmental 
consequences. Therefore, they determined that areas with steep slopes (potentially 
subject to landslide or severe slope hazards) and areas subject to flooding were 
considered unbuildable for most types of urban development. It follows that protecting 
STGs with natural hazards has fewer adverse economic and social consequences for the 
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general public and for property owners - as least insofar as urban development is 
concerned. 
ESEE Consequences of Full and No Additional Protection Options for Land 
with Natural Hazards 
The full protection option would prohibit all conflicting uses and activities for STGs both 
within and outside of Title 3 Sensitive Land areas. The no additional protection option 
would mean that the City would not adopt the proposed Regulatory Incentives Program 
to STGS outside of Title 3 Sensitive Land areas. 
Environmental Consequences 
The environmental consequences of fully protecting all STGs are positive and are 
discussed under Goals 5 and 6. These positive environmental consequences are 
reinforced in natural hazard areas, because prohibiting all conflicting uses would further 
decrease the likelihood of flooding in flood-prone areas and slope failure in steeply-
sloped areas that in turn could adversely affect water quality in streams and harm fish 
and wildlife habitat. (See also discussion of environmental impacts under Goal 6.) 
The environmental consequences of the no additional protection option (not applying 
regulatory incentives) have limited adverse impacts given Tigard's existing regulations. 
Since STGs outside of Title 3 Sensitive Lands provide some flood retention and slope 
stability benefits, tree removal in STGs that are not already protected by Title 3 Sensitive 
Land regulations could marginally increase the likelihood of flooding and slope failure -
which in turn could degrade land and water quality and riparian habitat values. 
However, existing CWS stormwater management and erosion control requirements 
would minimize the impacts. 
Economic and Social Consequences 
The economic and social consequences of full STG protection (prohibiting all conflicting 
uses) would generally be negative. The full protection option would prohibit all 
conflicting uses and activities within STGs, with adverse economic and social 
consequences to property owners, the general public and urban service providers. Such 
a complete prohibition would severely restrict the use of property for non-construction 
purposes (e.g./ yards and gardens), increase the costs of providing public infrastructure, 
restrict public recreational opportunities, and increase transportation costs resulting from 
of out-of-direction travel. The full protection option would also limit the ability to locate 
passive recreational facilities in public parks, and the public would be unable to access 
natural areas with attendant adverse social consequences. 
In contrast, the no additional protection option would rely on existing floodplain and 
slope regulations found in Chapter 17.775 Sensitive Lands to address hazards- while 
allowing some conflicting uses with hazard mitigation measures. The no additional 
protection option thus avoids the excessive restrictions that would result from full 
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protection of all STGs. However, the no additional protection option does nothing to 
encourage STG protection. 
ESEE Consequences of Limited Protection Program for Land with Natural 
Hazards 
The Regulatory Incentives Program (limited protection program) provides incentives for 
STG protection outside of Title 3 Sensitive Land areas while maintaining existing 
regulations in areas already protected by Title 3 Sensitive Lands regulations. 
Environmental Consequences 
The environmental consequences of the proposed Regulatory Incentives Program are 
positive, because protection of STGs reduces runoff and erosion which can contribute to 
flooding and slide hazards. In this manner, the limited protection program reinforces 
existing Sensitive Lands regulations to protect people and property from natural 
hazards. 
Economic and Social Consequences 
Unlike the full resource protection option, the limited protection program allows 
conflicting private and public land uses and activities (uses allowed in the underlying 
zoning district, public utilities and transportation facilities) through density transfer and 
thoughtful site design -while encouraging protection of all or part of the STG on 
affected properties. 
Because the existing Sensitive Lands limited protection program allows for certain 
private and public uses and activities within hazard areas, subject to engineering and 
locational standards, adverse social and economic consequences are reduced without 
compromising public safety. 
Goal 7 Conclusion 
Existing Sensitive Land regulations protect STGs within Title 3 areas from most types of 
conflicting uses. The proposed Regulatory Incentives Program (limited protection 
program) applies outside Title 3 Sensitive Lands and provides an additional level of 
protection for tree groves on "buildable lands." 
These provisions have positive environmental consequences because they reinforce 
existing provisions that protect Title 3 Sensitive lands on a limited basis. The proposed 
TDC urban forest amendments that implement the Tree Grove Regulatory Incentives 
Program complement existing Goal 7, Natural Hazards, regulations by encouraging tree 
preservation with attendant erosion and flood control benefits. 
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Goal 8: Recreational Needs 
Goal 8 requires local governments to plan for the park and recreational needs of their 
community. This Goal is related to the Goal 14 requirement to provide land to meet the 
"livability" needs of a community. Many STGs overlap publicly-owned land or land 
reserved for public park and recreational use. In addition, STGs that are protected 
through the Regulatory Incentives Program must be dedicated to the public or protected 
via a conservation easement. In this sense, protected STGs will become part of Tigard's 
park and open space system. 
ESEE Relationship to Goal 8 
Planning for, developing and maintaining Tigard's system of parks, open space, and 
trails are indirectly related to the level of protection of afforded to STGs in the 
community. On the one hand, protecting STGs provides open space and may provide 
recreational opportunities for the residents of nearby developments, which translates 
into positive social and economic consequences. On the other hand, park development 
and human access to STGs areas can have some adverse environmental consequences. 
ESEE Consequences of Full and No Protection Options for Meeting Long-
Term Park and Recreational Needs 
With respect to park and recreational uses, the full protection option means that STGs, 
outside of public property, would be largely off limits to the public. Relatively minor 
conflicting uses such as pedestrian and bicycle trails, picnicking, and passive recreational 
uses - which can conflict with the preservation of wildlife habitat in STGs - would not be 
permitted under the full protection option. In contrast, the no additional protection 
option would allow unlimited development of STGs for residential, commercial, industrial 
or public uses - meaning that the limited wildlife habitat, water quality, flood control and 
slope stabilization values of STGs would be compromised. 
Environmental Consequences 
The environmental consequences of the full protection option are positive because 
conflicting active and passive recreational uses would be prohibited. Conversely, the 
environmental consequences of allowing conflicting park development without restriction 
would be negative, because environmental values described in the Goal 5, 6 and 7 
sections of this ESEE Analysis would be lost. 
Economic and Social Consequences 
The economic consequences of the full protection option would be adverse for reasons 
stated in the Goals 9-14 sections of this ESEE Analysis. In contrast, the no additional 
protection option would do nothing to protect privately owned STGs for their open space 
and scenic values. 
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ESEE Consequences of Limited Protection Program for Meeting Long-Term 
Park and Recreational Needs 
The limited protection program provides strong incentives for the protection of STGs-
especially in residential areas. In many cases, STGs overlap both private property and 
publicly owned parks and open space areas. 
Environmental Consequences 
The environmental consequences of the proposed Regulatory Incentives Program are 
only slightly negative. Passive recreational use of protected STGs by Tigard and area 
citizens will have some adverse environmental impacts on natural resource values. 
Economic and Social Consequences 
These relatively minor adverse environmental consequences are more than offset by the 
economic and social benefits that local residents and visitors derive from having visual 
and possibly physical access to STGs that are protected through voluntary regulatory 
incentives. (See discussion of open space benefits in the Goal 5 section of this ESEE 
Analysis.) 
Goal 8 Conclusion 
The proposed STG Regulatory Incentives Program, as implemented by draft 
amendments to TDC Chapter 18.790 Urban Forestry, will have the effect of augmenting 
the City's park and open space system. The limited protection program avoids the 
extremes of full protection (i.e./ nature parks that no one can use) on the one hand, and 
no additional protection (i.e., unrestricted development and loss of STGs) on the other. 
Therefore, the proposed legislative changes comply with Goal 8, Recreational Needs. 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 3. Tigard ESEE Analysis 
Prepared by Winterbrook Planning 
November 2011 
City of Tigard Urban Forc>try Code RcYi>ion> I \'olumc II I 272 
Page 3-30 
Goal 9: Economy of the State 
Goal 9 requires Tigard to provide sufficient and buildable land within its City Limits to 
meet long-term needs for industrial, commercial, office and mixed use development. 
ESEE Relationship to Goal 9 
The Goal 9 ESEE Analysis applies to land that is designated for employment (industrial, 
commercial, and office) uses on the Tigard Comprehensive Plan Map. The primary 
concern is that Tigard must maintain an adequate supply of land to meet its economic 
development objectives as expressed in the recently-adopted Tigard 2011 Economic 
Opportunities Analysis. If land is removed from the industrial, commercial, or office 
buildable lands inventory to protect Goal 5 resources, and the supply falls below the 
needs projected in the EOA, then Goal 9 compliance is jeopardized. 
Conflicts between Goal 9 and Goal 5 resources often are difficult to resolve because 
commercial and industrial buildings are often single story and require large parking lots 
and maneuvering areas. Unlike residential areas, density transfer usually is not a viable 
option. 
The Tigard City Council adopted the EOA in May of 2011. The EOA analyzes three 
employment land need scenarios C'efficient", "medium", and "high''). The employment 
land need in each scenario is compared to Tigard's existing buildable employment land 
supply. As discussed below, there are commercial and industrial land deficits in the 
Medium and High land use scenarios. 
Proposed Section 18.790.050.C.3 encourages STG protection on commercial and 
industrial land when at least 50% of an STG on a commercial or industrial property is 
protected. Setbacks may be reduced by as much as 50% and heights may be increased 
up to 20%. Modifications to sidewalk, parking and landscaping location requirements 
standards may be permitted for STG protection. However, as noted below, the concept 
of density transfer has limited utility for commercial and industrial development types. 
ESEE Consequences of Full and No Protection Options for Economic 
Development Objectives 
Environmental and Energy Consequences 
Approximately 34 buildable acres with STGs are designated for commercial or industrial 
use in Tigard; four additional acres are designated for mixed employment uses. 
The full protection option would have positive environmental consequences for the STGs 
located on employment land; these positive environmental consequences are described 
in the Goal 5, 6 and 7 sections of this ESEE Analysis. 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 3. Tigard ESEE Analysis 
Prepared by Winterbrook Planning 
November 2011 
City of Tigard Urban Fores try Code Rc,·isions I Volume II I 273 
Page 3-31 
In contrast, the no additional protection option could have adverse environmental 
consequences - because there would be no incentive to protect STGs on scarce and 
valuable employment land. 
As noted in the Goal 13 section, the full protection option could have serious adverse 
energy consequences because industrial jobs would be forced into other communities, 
thus increasing commuting distances and energy consumption. The result is unlikely in 
the no additional protection option. 
Economic and Social Consequences of Full and No Protection Options 
In commercial and industrial areas of Tigard, STGs can have some economic and social 
benefits, including reduced stormwater management and energy costs. Other economic 
benefits include improved consumer perceptions of businesses and greater worker 
productivity and job satisfaction. However, where large STGs are concerned, these 
benefits are less pronounced and are offset by the loss of buildable commercial and 
industrial land and corresponding loss of local job opportunities. 
Consumer Perceptions and Behavior 
A recent study by researchers at the University of Washington found that consumers 
respond positively to commercial shopping environments with attractive trees and 
landscaping. Well-maintained landscapes with trees send positive messages about the 
appeal of a business district, the quality of products they offer, and the quality of 
customer service. Surveys were sent to selected districts in cities of the Pacific 
Northwest, Austin, Los Angeles, Chicago, Pittsburgh, and Washington, DC (Wolf 1999). 
Researchers identified four categories of perceptions from participants' ratings of 
business districts: Amenity and Comfort, Interaction with Merchants, Quality of Products, 
and Maintenance and Upkeep. Consumers rated districts that had street trees and other 
landscaping significantly higher than those that did not. For example, Amenity and 
Comfort ratings were 80% higher, Quality of Products ratings were 30% higher, and 
Interaction with Merchants ratings were 15% higher (Wolf 1999). 
The study also found that consumers are willing to pay as much as 12% more for 
products purchased in well-maintained and landscaped business districts with trees. 
This was true of low-price, convenience goods as well as bigger ticket items. "Given the 
low profit margins of most retail businesses," the researchers concluded, "trees appear 
to provide a significant amenity margin" (Wolf 1999). 
These studies support the full protection option for STGs located at the edge of 
commercial retail and office areas or where a STG is located on slopes of 10% or 
greater - where it is possible to avoid the STG and still provide a suitable building site. 
However, with regard to STGs in industrial areas, the full protection option would offer 
relatively few of these economic and social benefits because the STGs are too large to 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 3. Tigard ESEE Analysis 
Prepared by Winterbrook Planning 
November 2011 
City of'l'igarJ Urban Forestry C:oJe Rc,-isions I \'olumc II I 274 
Page 3-32 
be integrated into an industrial development. Moreover, industrial land usually is not 
intended to attract consumers. 
The no additional protection option would provide no incentive for protection of STGs on 
employment land and therefore would have no effect on the supply of employment land 
in Tigard. 
Worker Productivity and Job Satisfaction 
Visual contact with trees can also improve office worker productivity and job satisfaction 
(Kaplan and Kaplan 1989). Office workers with a view of trees and greenery: 
1) Found their job more challenging, 
2) Were less frustrated about tasks and generally more patient, 
3) Felt greater enthusiasm for the job, 
4) Reported feelings of higher life satisfaction, and 
5) Reported better overall health. 
Office workers without a view noted 23% greater incidence of illness in the prior six 
months (Kaplan and Kaplan 1989). Again, these studies apply more directly to office or 
industrial park workers and less to manufacturing and assembly workers. These 
benefits are off-set in industrial and commercial areas by the high costs of industrial and 
commercial land, and the need to use such land efficiently within the Tigard City Limits. 
In conclusion, the full protection option would mean that no development could occur 
within protected STGs. Given the limited supply of employment land in Tigard, this 
option could severely restrict expansion of businesses and could severely limit areas 
where new commercial and industrial development could occur. Tigard could become 
noncompliant with Statewide Planning Goal 9 (Economic Development). Job growth in 
Tigard could be greatly impaired. For these reasons, full resource protection in Tigard is 
not a realistic public policy option. 
On the other hand, in commercial retail, office, and industrial park areas, unrestricted 
development could remove all vegetation and offer no additional protection for STGs. 
The no additional protection option, when applied on a City-wide basis, could have some 
adverse economic consequences for businesses, as noted in the Goal 5 section of this 
ESEE Analysis. Well-maintained trees and landscaped areas send positive messages 
about the appeal of business districts, the quality of products they offer, and the quality 
of customer service, as noted above. However, other City standards require attractive 
landscaping and canopy cover; so the loss of STGs per se would be unlikely to have a 
significant cost impact in terms of business sales. 
In summary, STGs provide important amenity values for employees as well as business 
customers. Their presence increases worker productivity and job satisfaction 
significantly. These benefits could be reduced when conflicting uses are fully allowed 
and vegetation is cleared. However, Tigard's landscaping and tree canopy requirements 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 3. Tigard ESEE Analysis 
Prepared by Winterbrook Planning 
November 2011 
City of Tigard Urban Forestry Code Rc,-isions I Volume II I 275 
Page 3-33 
will replace these lost benefits over time. Thus, in Tigard's case, the economic 
consequences of no additional protection are not substantial. 
ESEE Consequences of Limited Protection Program for Economic 
Development Objectives 
To address the negative ESEE consequences of the full and no additional protection 
options, Tigard has developed a limited protection program that provides limited 
incentives (in terms of setback reductions and building height increases) for retention of 
STGs on employment sites. Proposed Section 18.790.050.C.3 encourages STG 
protection on commercial and industrial land when at least 50% of STG on a commercial 
or industrial property is protected. Increases include the following: 
• Minimum setbacks may be reduced by as much as 50%; and 
• Maximum building heights may be increased by as much as 20 feet. 
• Adjustments to sidewalk, parking and landscaping standards may be permitted 
to facilitate STG preservation. 
• Protected STGs count double towards the tree canopy requirements of Chapter 
18.790.050 Urban Forestry Plan. 
Table 3.2 below compares employment scenario outcomes with STG acreage in 
Commercial and Industrial zones. As shown on Table 3.2, Tigard currently has a surplus 
of employment land (8 commercial acres and 2 industrial acres) under the "efficient" 
land need scenario, and deficits of both commercial and industrial employment land 
under the "medium" and "high" land need scenarios. There are 9 acres of STGs on 
buildable commercial land, 25 acres on buildable industrial land. In all scenarios, full 
preservation of STGs would result in a deficit of buildable commercial and industrial 
employment land . 
Table 3.2: Impact of STGs on Buildable Employment Land* 
STG Com Land lnd Com Acres on Surplus lnd STG Surplus EOA Land Buildable (Deficit) Land Acres on (Deficit) Scenario Surplus Com with Full Surplus Buildable with Full (Deficit) Land Protection (Deficit) lnd Land Protection 
ofSTGs ofSTGs 
"Efficient" 8 (1) 2 (23) 
"Medium" (19) 9 (28) (14) 25 (39) 
" High" (45) (54) (30) (55) 
Note: bu ildable employment land is by defin ition located outside of areas that are already 
protected by the Metro Title 3 provisions of TDC Chapter 17.775 Sensitive Lands. 
However, given the short supply of commercial and industrial land in Tigard, it is 
doubtful whether a property owner would choose to use these setback, height and tree 
canopy incentives to protect the 50% of an STG located on buildable land. However, 
developers might take advantage of the setback, height and tree canopy compensation 
benefits to protect trees at the edge of large properties or on relatively unsuitable slopes 
(e.g., " buildable" slopes of between 10 and 25%). Winterbrook estimates that 
City of Tigard Urban Forestry Project 
ESEE Analys is • Section 3. Tigard ESEE Analysis 
Prepared by Winterbrook Planning 
November 2011 
City of Tigard Urban Forestry Code Re,·isions I \ 'olume II I 276 
Page 3-34 
regulatory incentives will protect about 10% (4 acres) of the STGs located on buildable 
commercial and industrial land. Table 3.3 shows the results of this estimate : 
Table 3.3: Impact of STGs on Buildable Employment Land Assuming 20% 
Effectiveness 
Protected Com land Protected lnd Com STG Surplus lnd STG Surplus EOA Land Acres on (Deficit) Land Acres on (Deficit) Scenario Surplus Buildable with Full Surplus Buildable with Full (Deficit) Com Protection (Deficit) lnd Land Protection Land ofSTGs ofSTGs 
"Efficient" 8 6 2 (1) 
"Medium" (19) 1 (21) (14) 3 (17) 
"High" (45) (47) (30) (33) 
Under Winterbrook's 10% estimate: 
• Tigard will barely meet its 20-year commercial land need under the "efficient" 
development scenario, but will not meet 20-year commercial needs under either 
the "medium" or "high" land use scenarios. 
• Tigard will not meet its 20-year industrial land need under the "efficient", 
"medium" or "high" land use scenarios. 
Goal 9 Conclusion 
Tigard has a very limited supply of buildable industrial and commercial land. /fTigard 
were to protect all of the STGs on employment land, the City would be unable to meet 
employment land needs identified in the EOA. 
The setback and height incentives of the proposed Regulatory Incentives Program are 
unlikely to result in the actual protection of more than 10% of STGs on buildable 
industrial and commercial land. Even under this limited protection program, Tigard will 
still have a shortage of industrial land in all three of the EOA's development intensity 
scenarios, and a shortage of commercial land in all but the "efficient" scenario. 
Thus, the economic consequences of both the full protection and the limited protection 
options could be adverse. If the Council decides to encourage STG protection on 
employment land, Tigard planning staff should monitor the effectiveness of the STG 
protection program and, if actual buildable acreage falls below identified 20-year need, 
the City should amend its comprehensive plan to ensure a sufficient supply of buildable 
land for the 20-year planning period. 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 3. Tigard ESEE Analysis 
Prepared by Winterbrook Planning 
November 2011 
City of Tigard Urban Forestry Code Re,·isions I Volume 11 I 277 
Page 3-35 
Goal10: Housing 
Goal 10 requires Tigard to provide sufficient buildable land to meet long-term housing 
needs, as required by Metropolitan Housing Rule (OAR Chapter 660, Division 007) and 
ORS 197.303.14 The Metropolitan Housing Rule requires Tigard to plan for at least a 
50 :50 split between attached and detached housing types, at a minimum of 10 units per 
net buildable acre. Providing for a variety of affordable housing opportunities in well-
designed and livable neighborhoods is also a primary consideration in the Tigard 
Comprehensive Plan. 
ESEE Relationship to Goal 10 
The Goal 10 ESEE Analysis applies to land that is designated for Low, Medium, and High 
Density residential uses, and for Mixed Use Residential, in the Tigard Comprehensive 
Plan. Tigard must maintain an adequate supply of buildable land to meet the 
requirements of the Metropolitan Housing Rule as well as meeting Metro Title 1 density 
requirements. 
As noted in Table 2.2, Tigard has 70 STGs covering 544 acres of which 124.5 acres 
qualify as " buildable". Most the STGs identified in the Tigard Tree Grove Assessment 
are located on land planned and zoned for residential use: 450 overall acres (83%) and 
86.5 buildable acres (69% of buildable acres) . An additional 19 STG acres are 
designated Mixed Use - with 4 buildable acres. Thus, under the full protection option 
there is the potential for reducing the buildable residential land supply by 90.5 acres. 
If land is removed from the residential buildable lands inventory to protect 
STGs, and the buildable land supply is altered such that Division 007 rule 
requirements are not longer met, then Goal 10 compliance is jeopardized. 
ESEE Consequences of Full and No Protection Options for Meeting 
Housing Needs 
Environmental Consequences of Full and No Protection 
14 197-303 " Needed housing" defined. (1) As used in ORS 197·307, unti l the beginning of the first periodic review of 
a loca l government's acknowledged comprehensive plan, "needed housing" means housing types determined to 
meet the need shown for housing within an urban growth boundary at part icu lar price ranges and rent leve ls. On 
and after t he beginning of the first periodic review of a loca l government's acknowledged compre hensive plan, 
"needed housing" also means: 
(a) Housing t hat includes, but is not limited to, attached and detached sing le-fami ly housing and multip le 
fami ly housing for both owner and renter occupancy; 
(b) Government assisted housing; 
(c) Mobi le home or manufactured dwell ing parks as provided in ORS 197.475 to 197.490; and 
(d) Manufactured homes on individua l lots planned and zoned for sing le-fami ly residentia l use that are in 
addition to lots within designated manufactured dwell ing subdivisions. 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 3. Tigard ESEE Analysis 
Prepared by Winterbrook Planning 
November 2011 
City of Tigard Urban l'orcstry Code Rc,·isions I \'olumc II I 278 
Page 3-36 
The environmental consequences of the full protection option could be highly positive 
for reasons stated in the Goal 5, 6 and 7 sections of this ESEE Analysis. By prohibiting 
all types of residential development, including site preparation (vegetation removal and 
grading) and construction of supporting public facilities and services, STGs and their 
attendant environmental values could remain largely intact. 
On the other hand, the environmental consequences of allowing all residential uses 
without incentives for STG protection (no additional protection option) could be 
extremely negative for the same reason: the majority of Tigard's STGs are located on 
land planned and zoned for residential use. Unrestricted residential development could 
result in loss of the STG functions and values described in the Tree Grove Assessment 
and in the Goal 5, 6 and 7 sections of this ESEE Analysis. This option would be 
inconsistent with the STG conservation policies found in both the UFMP and the Tigard 
Comprehensive Plans. 
Neither of the above policy options offers the balance sought by Tigard decision-makers, 
for reasons discussed below. 
Economic and Social Consequences of Full and No Protection 
Neither the full protection option nor the no additional protection option achieves the 
balance envisioned in the Tigard Comprehensive Plan and called for in the UFMP. 
Full protection of all STGs - without automatic density transfer permitted in the limited 
protection option - could decrease the supply of buildable residential land by 86.5 acres, 
resulting in the loss of some 1,036 potential housing units (based on maximum 
residential capacity and assuming 20% right-of-way). Because most STGs are located 
on land planned for residential use, the economic consequences of full resource 
protection for property owners, developers, and existing and future residents could be 
extremely adverse. 
Assuming that raw residential values in Tigard are in the $400,000 per acre range, the 
cumulative impact of the full protection option (without density transfer or other benefits 
provided by the limited protection option) could be in the $32m range. To a certain 
extent, these costs would be transferable to future consumers of housing and would 
reduce developers' ability to provide affordable housing opportunities. 
Since the City has a limited supply of buildable land available to meet housing needs 
over the next 20 years, the full protection option (again, without the automatic density 
transfer encouraged under the limited protection option) could limit Tigard's ability to 
provide for needed housing as required by Goal 10. Some 86.5 acres of buildable land 
would be off-limits to development, which could decrease the supply of land available 
for housing and could drive up housing costs for existing and potential residents of the 
area. Moreover, the full protection option could make it impossible to extend public 
facilities and services necessary to support needed housing, in conflict of both Goals 10 
and 11. 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 3. Tigard ESEE Analysis 
Prepared by Winterbrook Planning 
November 2011 
City o f Tigard Urban l'orcstry Code RcYisions I Volume II I 279 
Page 3-37 
The full protection option also could have negative economic consequences for many 
property owners. While the benefits of STGs could be preserved, prohibiting housing in 
all such resource areas could deprive some property owners of reasonable economic use 
of their land. For vacant and partially developed residential lands, full protection of STG 
resources in Tigard could adversely impact the dwelling unit potential of these lands, or 
eliminate development potential entirely. 
However, as noted below, the full protection option could have a number of positive 
economic impacts. Economists, ecologists, and urban forestry researchers have 
documented a wide range of economic benefits that natural open space provides to local 
communities. As noted in the discussion of the Regulatory Incentives Program (limited 
protection option), these benefits are better achieved when STGs are integrated into the 
design of neighborhoods and density transfer allows housing needs to be met in a more 
compact configuration. STGs in particular add considerable value to existing and 
developing residential neighborhoods, both for neighbors and for individual property 
owners. 
Property Values 
STGs contribute to the economic vitality and stability of a community by increasing 
property values. The values of houses in wooded neighborhoods have been shown to 
be higher than those of comparable houses in neighborhoods without trees (Morales 
1980; Morales et al. 1983). Research shows that people will pay 3-7% more for 
properties with significant tree cover versus those with few or no trees. Other studies 
have suggested that healthy, mature trees may add up to 10% or more to a property's 
value (Neely 1988). In a major study of the influence of trees on property values, 
Anderson and Cordell (1988) surveyed actual sales prices of 844 single-family residences 
and found that each large front yard tree was associated with a 0.88% increase in 
average home sales price. They found that developers were able to capture the 
increase in value by protecting trees in buffer zones; the same logic could apply to STGs 
adjacent to developed residential lots or subdivisions. 
Studies in the Portland metropolitan area have shown that nearby forested areas and 
other types of open space increase homes sales prices. For example, a study compared 
the relationship between a home's sales price and its proximity to different open space 
types (Lutzenhiser and Netusil 2001). Five open space types were evaluated: urban 
parks, natural area parks, specialty parks/facilities, golf courses, and cemeteries. 
Natural area parks contained more than 50% native and/or natural vegetation with a 
focus on habitat preservation and passive recreation (e.g./ hiking, wildlife viewing). The 
study found that property values are positively and significantly related to proximity to 
open spaces (for all open space types except cemeteries). Natural area parks within 
1,500 feet of a home were shown to have the largest effect on home sales price 
($14,992 in 2003 dollars). Other open spaces also had statistically significant effects: 
golf courses ($12,459), specialty park I facilities ($7,965), and urban parks ($1,709). 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 3. Tigard ESEE Analysis 
Prepared by Winterbrook Planning 
November 2011 
City of Tigard Urban l'orcstry Code Rc,·isions I \'olumc I I I 280 
Page 3-38 
Stormwater Management 
As noted in the Goal 6 and Goal 11 discussions, natural resources can substantially 
reduce housing costs by reducing the costs of stormwater infrastructure. For example, 
trees within STGs intercept rainfall on leaves, branches, and trunks, and from there, the 
water evaporates (through evapotranspiration) or slowly soaks into the ground. Tree 
groves can provide significant rainfall interception. In Western Washington and Oregon, 
for example, a single mature oak tree can intercept more than 1,100 gallons of 
rainwater per year (McPherson et al. 2002). For this reason, trees within an STG can 
help to reduce stormwater runoff and lower the costs of stormwater management. 
A recent study showed that trees in metropolitan areas provide enormous benefits in 
terms of reducing the costs of managing stormwater runoff. The study showed that 
trees in the city reduced runoff by more than 18 million cubic feet, translating into a 
stormwater management value of nearly $110 million, or about $400,000 expressed on 
an annual basis (American Forests 2001). 
Under the no additional protection option, the economic benefits described above could 
likely be lost. If STGs were to receive no additional protection and are fully developed, 
there could be direct adverse impacts on the community livability, a reduction in 
property values for those living near natural resource areas, and a substantial increase 
in stormwater management and energy costs that could be transferred to homebuyers 
and owners. 
ESEE Consequences of Limited Protection Program for Meeting Housing 
Needs 
To address the negative ESEE consequences of both the full and no additional protection 
options, the Tigard CAC recommended the Regulatory Incentives Program. Tigard 
proposed to adopt an extremely effective density transfer program. As noted in Table 
18.790.1 (copied from Section 4 of this ESEE Analysis below), proposed TDC revisions 
provide for automatic and objective residential density transfer provisions that are 
proportional to the tree grove area that is fully protected (by dedication to the city, a 
conservation easement or similar deed restriction). Adjustments to sidewalk, parking, 
landscaping and lot size and dimensional standards may be permitted. 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 3. Tigard ESEE Analysis 
Prepared by Winterbrook Planning 
November 2011 
City of Tigard Urban Forestry Code RcYisions I Volume II I 281 
Page 3-39 
Table 18.790.1 (from draft TDC 18. 790.050) Proposed Residential Incentives 
DENSID ' T RANSFE R TABLE FOR PRESERVATION OF SIGNIF ICANT T REE 
GROYES 
Residential 
Zortin: 
District 
R.:.1 
Qll QQI) <;Q, 
ti DC"( LLLllt'l 
.li:l 
(?0,000 sg 
tt. 1>er nnitl 
~ 
( ! O.OQO fQ, 
ti . 1Jte( nn.irl 
R-4 5 
a 5oo SQ 
li. vet unit~ 
.11:1 
tS.fiQO ~% 
ti ocr lltUt ) 
,R;,;l2; 
no~o 1x-r 
~ 
R-25 
(1 .481) <;Q 
li .. nt r !ln.irl 
B.::i!l 
Oetru:;h gd SQ. 
~ 
Perren t L ·cc 
Groys: C..1 no~y 
Pl'•'Ni'I''ed I 
M:i.n LDt 01 P nir 
,QWJ. 
;~d$r?{( / ~"" 5C. I "'J tj 
51\." -it • i 1 ~ (M') I 'fl fr 
-?: tf(l·.~-. ,• - ; 1)1 w t't 
..,._.,cy:J.•i / ] =i OC(l ;g tl 
5(L - ,J.<••r / 10 000 IQ fr 
•5: I fK I''Q I 5 ff,!t "'I (r 
::,?d2h / - =\00 1Q ft 
5CL • .j.O:, ·' .. 000 '\Q f1 
~!oo·y, • ·' ; oo ;q it 
75-:fSJ?.·& ,. ; 6 "'~~. '9 ft 
~?~. t'~'! ·' ? - :;p 1Q ft 
-.... too·.p · 1 If-, 'Iii tr 
5d2)<'s / J - so 1Q fr 
51} • .f('/, ,.. ' "W> lQ n 
-, .! 001 \ . •' 1 ' i D 'Q tt 
Attache-d SQ. 
.EL. 
Pouot Tree 
Groyr Cam~n 
PltX'l"'t.-l I 
;\l jo Lot or 
llnit A i'C'a 
N ot Alloy;rd 
Pt ml!Hrd w1 t}1 -s·& 
R' grqs« t«t ero:rs 
C"n'ifli}Y J)«Jt?rJ'KhQt) 
l t. .(M)I '•"~ tr 
Pggjlin c:d wiW -s·,'£ 
w ftrhttr rNr smrt 
rn n ry:u · p rrspoo·a·hon 
,' 2.51)) !0. tL 
P"'rnnHed »"'tb -s•.>· 
m C"tiS'J " " etott 
AQRilY pgscryarigq 
UJl'"'i~__fr_ 
rsrm,;nm ,..ir)1 -s•<p 
ru {Tt'Utr r .... x cr&•'i'C 
rnnmt• nrr:sr p ·nho!J 
,• I :!50 !.0 _ t l 
Duplex 
Pem:m L'tt 
GiDve Canop\' 
Prr m yrd / 
Mill Lor or l "uit 
An: a 
?:io t Allgw cd 
:siot Allm.yed 
PrrmirrsQ W it - s ~"~a 
Qt grtarcr rrec pri)W' 
(.] DO (V prr•,10rynhpp 
•' 5.M "'· lt. 
Pr n mltterl rotl' - ; ob 
Qf f(£8!£f FE££ fW}"f 
SI;OQW pg;scmtioo 
·~_fi:_ 
P£mginrQ y.jrh -sc;.ia 
pr ert!'tr [ret erro'C 
pjl nnpr n rr •.cmlhpn 
,' ~I~L1t 
Multjfamil)' 
ptu·gu I rre Gp"''~e 
C a,!lopy Pre:Kcrffi I 
Mig V nit /vra 
Ng! Allg wed 
Not Allowed 
N Q! Allowed 
Npt r\Llow,d 
Nqi Allowed 
Sj,'E']e fam ih', dnp)e:s an d mnlrifamilr housing Pfr'mi ned ar rl,e t'oU,)winr• ,JeMiries· 
2 2-49"-'R t rrr KWiS' camwr pm-rwatio!l l '? .28B ~Q , h PS" •1pit 
5fl-74o:>.;, u ee ~~-...... •) ulopy Pl<"serymi •~ll / Vi:!.'> S<} ic f~<'Ol !ljt 
" 5-100''-'o r.rcc P1D\~C' G l UODr D~~i'\"':.'!ti.o ,\ / 763 S£1 ft Oi'i ' Ullit 
Si•lrle fam ih·, d•Jp)e:s and mnlrit,.mik housin g Pf•mirred ar rhe t'nUowj''k' de .. siries· 
'5-49'"9 rrrr f!O'i'; CiilHQPf ~''Kmtjoo I 1 ! 10 SQ ft l~'' LLL)jr 
51)-74°·'<:· ti"'{'S' iWYS' canQRY JXrsm·ation I 740 sg t't 1¢£'1' unit 
75. 100 (',"o [J 'ff L"!J ( JX'f r" !l: !l 'u '"r f)'{' 1)1 P>t.P1'\..-!l t:.-u l / ."; 7(1 ~-._ fr. I"'Wr' n ,·, · 
Sin\dt faLnjlr , dn1)Ja iUld nn1hit~1 n)YI' hqnsju~ r,enpjned \\?rh no nppe' dtu~o· 
J.imi.L. 
As shown on Table 18. 790.1, if 50% of a tree grove on a given property is preserved, 
then an increase in density of 50% is permitted outright- without a formal adjustment. 
If 75% of more of a tree grove is protected, attached housing and duplexes are allowed 
in low density residential zones to facilitate density transfer. Substantial reductions in 
front, garage and sideyard setbacks, and lot width - as well as a 20% increase in 
building height- are permitted to facilitate density transfer provisions. Substantial 
variations from development standards are also permitted (25% reduction in average 
minimum lot width; 10 foot (rather than 15 or 20 foot) front yard setbacks; 33% 
reduction in side and rear setbacks; 4 foot (rather than 20 foot) garage setbacks; and 
20% increase in maximum height. 
Economic and Social Consequences of Limited Protection Program 
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The Limited Protection Program achieves the social and economic balance called for the 
by the Tigard City Council when it authorized staff to prepare an incentive-based 
program to encourage STG preservation withoutloss in residential development 
potential. By encouraging the protection of STGs in residentially zoned areas through 
density transfer, the urban amenity benefits of natural resources are achieved without 
loss of residential development potential. 
To demonstrate continued compliance with Statewide Planning Goal 10, Winterbrook 
analyzed potential dwelling unit impacts that could result from the proposed Regulatory 
Incentives Program. Tigard has 86.5 STG acres on vacant buildable (undeveloped, 
outside of Title 3 areas) residentially-zoned land, impacting 71 tax lots with buildable 
land. These tax lots contain a total of 124.5 vacant buildable acres. Winterbrook ran 
three scenarios for STG preservation- assuming that 100%, 75%, and 50% of grove 
area retained - to see what impact, if any, the program would have on dwelling unit 
potential. The results of the three scenarios are shown on Table 3.4 below. 
Table 3.4: STG Preservation Scenarios 
Scenario STG Potential Potential 
Acres Dwelling Unit 
Lost Units Reduction 
No STG preservation 86.5 1,036 0 
50% STG preservation 43 1,036 0 
75% STG preservation 21 .5 1,036 0 
1 00% STG prese_rva_!!Qn 0 951 85 (8%) 
As shown on Table 3.4: 
• Existing residential zoning on the 71 tax lots with buildable land allows for a 
potential 1,036 dwelling units with no tree grove preservation.15 
• When 100% of the STG area is protected,16 some lots retain too little buildable 
area to accommodate density transfer effectively, resulting in a reduced dwelling 
unit potential of 951- a loss of 85 potential dwelling units (8%). 
However, it is extremely unlikely that a rational property owner or developer would 
protect 100% of a STG if it meant a reduction in actual dwelling units. 
Table 3.4 also shows that both the 75% and 50% preservation scenarios allow for full 
density transfer and 1,036 potential units. It is reasonable to assume that many 
property owners and developers will take advantage of the clear and objective density 
transfer provisions offered in draft TDC 18.790.050. Depending on the market, some 
developers may prefer to continue to build large-lot single-family housing where allowed 
by zoning. However, as noted in the Goal 11 section, infrastructure costs are likely to 
be lower when STGs protected and density is transferred because: (a) local street 
connections may not be required; (b) clustering of housing units will result in lower per 
unit costs for sanitary sewer and water services. Moreover, protecting STGs also 
15 Dwelling unit potential calculated using minimum lot sizes and an assumption of zo% ROW with development. 
16 Grove protection scenarios assume 15% ROW due to lack of ROW in STG areas. 
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reduces the tree canopy requirement for the developed portion of the property - which 
would further reduce development costs. Finally, more affordable duplex and attached 
housing types are permitted in lower density residential zones when at least 75% of an 
STG is protected on a property -which supports Goal 10 by increasing the potential for 
attached housing types in low density residential zoning districts. 
Overall, Winterbrook estimates that approximately 50% of STGs on buildable land will 
be protected because property owners and developers choose to take advantage of the 
density transfer provisions offered in proposedTDC 18.790.050. Thus, about 43 STG 
acres will likely be protected - with attendant economic, social, environmental and 
energy conservation benefits - if the proposed Regulatory Incentives Program is 
adopted. 
A couple of caveats are in order: 
1. lfthe density transfer and dimensional standard modification provisions of TDC 
18.790.050 were substantially weakened, it is unlikely that most developers 
would see an advantage in preserving STGs on their property. 
2. If the density transfer and dimensional standard modification provisions of TDC 
18.790.050 were subject to discretionary review, it is unlikely that planning 
commissioners (or city councilors on appeal) would approve a development in 
the face of organized neighborhood opposition. 
Therefore, in order for TDC 18.790.050 provisions to be effective in protecting STGs, 
they must be (a) proportional to the STG area that is protected, and (b) subject to clear 
and objective approval standardsY 
In conclusion, the proposed limited protection program is likely to increase rather than 
reduce needed housing opportunities in Tigard. In fact, per unit development costs 
would likely decrease if developers take advantage of cluster housing design options, 
and the values of homes near protected open space and scenic areas are likely to 
increase. 
Environmental Consequences of Limited Protection Program 
The environmental consequences of the Limited Protection Program (proposed 
Regulatory Incentives Program) are somewhat negative because only half of the 81 
acres of STGs on buildable residential land are likely to be protected. On the other 
hand, the portions of STGs that are retained as a result of density transfer will be better 
protected through public ownership or conservation easement than they would have 
been (under the " full protection" option) by local regulations. 
17 As noted in Section 1 of this ESEE Analysis, both Statewide Planning Goals 5 (Open Space and Scenic Resources) 
and 10 (Housing) requ ire clear and objective review and approval standards. 
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Goal 10 Conclusion 
The proposed STG Regulatory Incentives Program will help to achieve the economic, 
social, and environmental values of the Tigard Comprehensive Plan and UFMP as applied 
to urban residential neighborhoods. This program - which is based on clear and 
objective density transfer standards - avoids the extremes of the full protection option 
while protecting an estimated 50% of STGs on buildable land in Tigard. 
Goal11: Public Facilities and Services 
Goal 11 reads in relevant part as follows: 
To plan and develop a timely, orderly, and efficient arrangement of 
public facilities and services to serve as a framework for urban and rural 
development. Urban and rural development shall be guided and supported by 
types and levels of urban and rural public facilities and services appropriate for, 
but limited to, the needs and requirements of the urban, urbanizable, and rural 
areas to be served A provision for key facilities shall be included in each plan. 
Cities or counties shall develop and adopt a public facility plan for areas within an 
City Limits ... A Timely, Orderly, and Efficient Arrangement- refers to a system or 
plan that coordinates the type, locations and delivery of public facilities and 
services in a manner that best supports the existing and proposed land uses. 
Public facilities and services include sanitary sewer, domestic water, stormwater 
management, municipal government, schools, police, fire, electrical, and communication 
facilities. Park and recreational facilities and transportation facilities are addressed 
respectively in the Goal 8 and Goal 12 sections of this ESEE Analysis. 
ESEE Relationship to Goal 11 
Public facilities and services provide the supportive framework necessary for urban 
development, and the provision of such facilities through the annexation process is the 
primary growth management tool. 
Public facilities and services can conflict with the full protection of significant Goal 5 
resource areas. Construction of public facilities and services usually requires vegetation 
removal and grading and often results in construction of impervious surface area. As 
urban development occurs, an urban level of public facilities and services is required. 
Such services sometimes must pass through STGs to serve buildable land outside of 
such areas. Although facilities like sanitary sewer, water, electrical, and communication 
lines often are found in public street rights-of-way, sanitary sewer and stormwater 
management facilities function most efficiently under gravity-flow conditions and benefit 
from location in or adjacent to natural drainageways. Buildings, parking areas, and 
recreational I training structures associated with schools and fire stations conflict with 
STGs in a manner similar to residential or commercial uses. 
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Tigard has an acknowledged Public Facilities Plan (PFP) as required by Goal 11. Tigard 
also has detailed master plans for sanitary sewer, domestic water, and stormwater 
management. These facilities may conflict directly with full STG protection because 
there may be no reasonable alternative to routing these facilities through tree groves to 
serve nearby buildable land. The specific locations of these conflicts are found 
throughout the urban growth area. 
ESEE Consequences of Full and No Protection Options on the Efficient 
Provisions of Public Facilities and Services 
Environmental Consequences 
The full protection option would have mostly positive environmental consequences 
because vegetation removal, grading, and construction of hard surfaces associated with 
public facilities would not be permitted. The positive environmental consequences of 
fully protecting STGs are discussed in the Goal 5, 6 and 7 sections of this ESEE Analysis. 
The no additional protection option would mean that public facilities and services would 
be allowed without restriction or mitigation on, through or under STGs throughout the 
city. Such unregulated construction could adversely affect tree canopy, understory and 
root systems within STGs, with corresponding adverse impacts on wildlife habitat, scenic 
values, and water quality. This option could mean that no additional protections could 
be provided for STGs. Years of community work on a balanced and effective UFMP 
would be compromised. 
Economic and Social Consequences 
Tigard's growth management program depends primarily on ensuring that the full range 
of public facilities and services is available to support urban development. This program 
has substantial social and economic benefits to Tigard citizens and businesses. The 
growth management program helps to ensure an adequate supply of serviced industrial, 
commercial, residential, and public lands (with associated job opportunities). The 
growth management program also ensures that local shopping and services are 
available to residential areas, as are quality housing in well-designed neighborhoods, 
good and accessible schools, potable water, and adequate sanitation. By managing the 
direction and timing of growth, the public costs of providing public facilities and services 
are reduced. 
Tigard's growth management program goals would be difficult to achieve under the full 
protection option. This option could mean that no public facilities construction or 
maintenance could occur within protected STGs. Since significant natural resource areas 
comprise 544 acres of largely undeveloped land within the City Limits, avoiding such 
areas could preclude the efficient provision of public facilities and services that are 
necessary to support planned urban development. The economic and social costs to the 
public resulting from a different form of "leap-frog" development could be extremely 
high. 
City of Tigard Urban Forestry Project 
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For example, schools could be unable to expand into STGs under any circumstances. 
Sanitary sewer and water services could be required to be routed around STGs, 
regardless of public or private expense. This option could restrict future development 
patterns, both public and private, as roads and utilities could not be extended through 
resource areas. Tigard's quality-of-life and its appeal as a place to locate business could 
suffer substantially. 
In conclusion, Tigard's public facilities - particularly its parks, schools, and tree-lined 
streets - are an important part of the community's identity. Fully protecting all STGs 
could restrict urban growth and urban design options. Housing costs could increase, 
and job opportunities could be lost, with attendant social and economic impacts. 
Conversely, allowing unrestricted development of STGs could mean the loss or 
degradation of many of the economic benefits described previously. 
The full protection option could have at least one significant but frequently overlooked 
economic benefit. STGs provide substantial stormwater management benefits because 
they intercept or detain rainfall and reduce stormwater runoff. As noted in the Goal 6 
Section of this ESEE Analysis, STGs in Tigard significantly reduce runoff and stormwater 
management costs. (American Forests 2001) Unrestricted removal of trees to develop 
public facilities and schools would reduce the City's "green" stormwater infrastructure, 
necessitating the construction of extensive new facilities to address the increased storm 
flows. However, as noted above, these benefits can derive from the limited protection 
program as well. 
ESEE Consequences of Limited Protection Program for the Efficient 
Provision of Public Facilities and Services 
Unlike the full protection option, the limited protection program allows the construction 
of public facilities and services that are (a) permitted by the underlying zoning district 
and (b) necessary to support planned urban development, consistent with Statewide 
Planning Goal 11. TDC 18.810 Street and Utility Improvement Standards include 
development standards to ensure provision of public facilities necessary to serve 
development. However, the draft TDC 18.790.050(6) allows for adjustments to street 
and utility standards "to facilitate preservation and help to maximize the connectivity 
and viability of a significant tree grove ... " 
Environmental Consequences 
The UFMP includes policies to protect STGs through a regulatory incentives program. As 
noted in the introduction to the Goal 11 section of this ESEE Analysis, public facilities 
and services occasionally must be routed through STGs to serve nearby buildable lands, 
which could adversely impact the environmental values identified in the Goals 5, 6 and 7 
sections of this ESEE Analysis. However, impacts from public facility construction would 
be mitigated to a certain extent by Chapter 18.790.090 (Urban Forest Plan) standards. 
Economic and Social Consequences 
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Any negative environmental consequences from the limited protection program are more 
than offset by the positive economic and social consequences associated with the 
efficient provision of public facilities and services required by Tigard Comprehensive Plan 
policies and Statewide Planning Goal 11. By allowing public facilities and services to be 
constructed and maintained within STGs, subject to mitigation standards, the negative 
social and economic consequences described earlier in this section can be avoided. 
Goal 11 Conclusion 
The proposed Tree Grove Regulatory Incentives Program ensures that Tigard can 
continue to provide key public facilities and services necessary to support planned urban 
growth in a timely and efficient manner. This Goal 11 requirement is underscored by the 
policies of the Tigard Comprehensive Plan, and serves as the cornerstone for managing 
urban growth within the Tigard City Limits. There would be negative ESEE consequences 
for allowing public facilities to be constructed without restriction, or for prohibiting public 
facilities construction and maintenance in all protected natural resource areas. 
Goal 12: Transportation 
Goal 12 reads in relevant part as follows: 
To provide and encourage a safe, convenient and economic transportation 
system. A transportation plan shall {1) consider all modes of transportation 
including mass transit, air, water, pipeline/ rail highwafi bicycle and pedestrian; (2) 
be based upon an inventory of local regional and state transportation needs; (3) 
consider the differences in social consequences that would result from utilizing 
differing combinations of transportation modes; (4) avoid principal reliance upon any 
one mode of transportation; (5) minimize adverse social economic and 
environmental impacts and costs; (6) conserve energy; (7) meet the needs of the 
transportation disadvantaged by improving transportation services; (8) facilitate the 
flow of goods and services so as to strengthen the local and regional economy; and 
(9) conform with local and regional comprehensive land use plans. Each plan shall 
include a provision for transportation as a key facility. 
ESEE Relationship to Goal12 
Goal 12 requires that local governments plan for a multi-modal, interconnected 
transportation system. Goal 12 reinforces the Goal 5 requirement to consider the ESEE 
consequences of providing transportation facilities to meet this goal. Tigard has an 
acknowledged Transportation System Plan (TSP) that identifies pedestrian, bicycle, and 
vehicle projects, as well as their estimated timing, location, and cost. 
Some planned transportation facilities may conflict with full STG protection. Like other 
public facilities and services, transportation facilities and their impacts vary widely-
from multi-lane state highways to pervious-surfaced pedestrian trails. Local streets 
City of Tigard Urban Forestry Project 
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necessary to serve development are not necessarily shown on TSP maps, but may also 
have adverse impacts on significant natural resources. 
Economic, social and environmental consequences related to transportation facilities are 
considered in this section. The potential adverse energy consequences of the full 
protection option are considered in the Goal 13 section that follows. 
ESEE Consequences of Full and No Protection Options for Meeting Long-
Term Transportation Needs 
Most of the Goal 11 ESEE Analysis applies equally to planned transportation facilities. 
The full protection option could frustrate the construction of a multi-modal, 
interconnected transportation system; could decrease pedestrian and bicycle use; and 
could result in some out-of-direction travel. With diminished bicycle and pedestrian 
accessibility, transportation costs would increase and neighborhoods would become 
more auto-dependent. Full protection of resources in right-of-way areas could stop 
planned widening of Tigard streets and planned development of new roads. This could 
make the City and County noncompliant with Goal 12, as their joint Transportation 
Systems Plan could no longer be implemented. 
There are a number of ESEE benefits related to a multi-modal transportation system. 
Alternative modes of transportation, such as bicycling, buses, walking, skating, and 
carpooling or van pooling, as well as telecommuting, can reduce traffic congestion and 
provide benefits to individuals and to the community. Reduced traffic congestion and air 
pollution improve community livability. Less traffic reduces the need for additional, 
expensive roadway construction projects. Fewer vehicles on the road means less land is 
needed for parking facilities, allowing it to be used for open space or commercial and 
residential development. Walking, bicycling and skating can improve health and well-
being. 
There are also social consequences associated with bicycle travel. The bicycle is a 
healthy, non-polluting alternative to the automobile that helps to maintain the quality of 
life in Tigard. Almost all (95%) of Tigard's collector and arterial roadways have bicycle 
lanes, and there are many miles of multi-use paths. In addition, a large percentage of 
the city is laid out on a grid system allowing many alternative routes for cyclists to use in 
getting from one place to another. 
The full protection option would preclude the City from constructing transportation 
facilities - including new pedestrian and bicycle trails - through STGs. This would have 
substantial adverse social consequences for existing and future area residents and 
businesses. On the other hand, the no additional protection option would allow for 
transportation facilities to be constructed through STGs without considering alternatives 
and with limited mitigation. This could have substantial adverse impacts on the 
functions and values of STGs as described in the Goal 5, 6 and 7 sections of this ESEE 
Analysis. The no additional protection option would also adversely affect the quality of 
residential neighborhoods, with adverse social consequences. 
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ESEE Consequences of Limited Protection Program for Meeting Long-Term 
Transportation Needs 
Unlike the full protection option, the limited protection program allows the construction 
of transportation facilities that are (a) permitted by the underlying zoning district and (b) 
determined necessary to support planned urban growth consistent with the adopted 
TSP. TDC 18.810 Street and Utility Improvement Standards include development 
standards to ensure provision of transportation facilities necessary to serve 
development. 
Draft amendments to TDC 18.790.050(6) allow for adjustments to street and utility 
standards where necessary "to facilitate preservation and help to maximize the 
connectivity and viability of a significant tree grove ... " In other words, local street 
connections may not be required in order to save all or part of an STG; however, 
because bicycle and pedestrian trails have lower impact that streets, it is likely that 
pedestrian and bicycle connectivity can be maintained without substantial impacts to 
STGS. In this manner, the limited protection program allows city officials to balance 
connectivity needs with the clear benefits of STG protection. 
By allowing needed transportation facilities on a limited basis with mitigation, the 
proposed Tree Grove Regulatory Incentives Program allows for the full implementation 
of the Transportation Systems Plan with minimal adverse environmental impacts. 
Goal 12 Conclusion 
By allowing for the maintenance and expansion of existing transportation facilities, and 
the improvement of planned facilities with mitigation, adverse ESEE consequences are 
minimized. 
Goal 13: Energy Conservation 
Goal 13 is short and to the point. It reads as follows: 
To conserve energy. Land and uses developed on the land shall be managed and 
controlled so as to maximize the conservation of all forms of energy, based upon 
sound economic principles. 
ESEE Relationship to Goal 13: Energy Conservation 
One of the four key consequences that must be considered in the Goal 5 ESEE Analysis 
process is "energy consequences." Energy conservation is a theme that runs through 
several of the Statewide Planning Goals. Energy consequences must be explicitly 
considered under Goal 5 (Natural Resources), Goal 9 (Economy), Goal 12 
(Transportation), Goal 13 (Energy Conservation) and Goal 14 (Urbanization). Evaluation 
of energy consequences is also implied in the notion of "efficient" public facilities and 
transportation planning . This ESEE Analysis consolidates the consideration of energy 
consequences related to all applicable statewide planning goals in this section . 
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Energy Conservation Consequences of Full and No Protection Options 
As observed repeatedly in other sections of this ESEE Analysis, the full resource 
protection option in an urban context conflicts with key planning principles in the Tigard 
Comprehensive Plan, Metro functional plans, and several Statewide Planning Goals. This 
conflict is especially evident with respect to Goal 13, Energy Conservation. The 
following bulleted list summarizes adverse energy consequences (i.e., increased energy 
consumption) that would result from implementation of the full resource protection 
option within the Tigard City Limits: 
• Goal 5 (Natural Resources). The full protection option means that all STGs 
are preserved and no conflicting uses are allowed. Full protection of 544 STG 
acres would require urban services to avoid undeveloped STGs to reach buildable 
land - and would have the unintended consequence of increasing energy 
consumption. 
• Goal 8 (Parks and Recreation). The full protection option would make it 
impossible to develop or gain access to park and recreational facilities associated 
with STGs. Even in natural areas, trails, access roads, and parking areas would 
be prohibited. Without such local connections, area residents would be forced to 
drive long distances to reach park and recreational facilities, with attendant 
increases in energy consumption. 
• Goal 9 (Economy). The full protection option would reduce the supply of 
industrial and commercial land available for development in Tigard, with 
attendant reductions in (a) local shopping and service opportunities, and (b) 
jobs. These reductions would force people to drive further to reach local 
shopping and service destinations and employment, and people would be less 
likely to bike or walk to work, with attendant increases in energy consumption. 
• Goal 10 (Housing). The full protection option (without density transfer and 
dimensional adjustments) would increase totalhousing costs. Total housing 
costs include transportation and energy costs, and the costs of services like 
sewer, water, and storm drainage. Under the full protection option, Tigard's 
buildable land supply would be reduced, the costs of providing public facilities to 
serve new housing areas would increase, and travel distances to housing would 
increase as well - resulting in overall increased housing costs. To reduce direct 
housing costs, people are willing to drive further, with attendant increases in 
energy consumption. Thus, an important consideration in maintaining an 
affordable housing supply is to maintain a buildable land supply near the urban 
center and natural amenities, which has the effect of reducing the need to drive 
a single-occupancy vehicle (SOV) with attendant energy savings. 
• Goal 11 (Public Facilities). The full protection option would require public 
facilities to be routed around natural resource areas, which would increase 
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energy needed to construct and maintain more dispersed public facilities. 
Because several STGs are associated with natural drainageways, this option 
would likely require the use of pump stations because gravity flow sewer would 
be impossible if all sewer lines needed to be located outside of natural drainage 
areas. This option could also limit construction of higher elevation water storage 
reservoirs in natural resource areas, leading to increased consumption from 
booster pumps. Emergency services could be more expensive to provide, and 
fire, police, and ambulances would be required to serve a more dispersed area, 
thus consuming more energy. The effect of avoiding any impacts to STGs could 
be increased energy costs associated with the provision of key public facilities 
and services. 
• Goal 12 (Transportation). As noted in the Goal 12 discussion, the full 
protection option would make implementation of the TSP difficult, primarily due 
to needed intersection improvements and road widenings. The TSP calls for a 
multi-modal, interconnected systems of streets, pedestrian and bicycle facilities, 
and transit facilities. If the TSP could not be implemented, people would be 
more reliant on SOVs, there would a substantial increase in out-of-direction 
travel, and energy consumption would increase dramatically. 
• Goal14 (Urbanization). Finally, the full protection option (without density 
transfer and dimensional adjustments) could result in a less compact urban form, 
which would disperse housing, jobs, and parks, and force even more reliance on 
SOVs. Passing over otherwise buildable areas to achieve full resource protection 
could result in an inefficient growth form. The lack of a compact urban form 
would have direct and adverse impacts on energy consumption. 
There are, however positive energy consequences associated with the full 
protection option. Urban areas typically are warmer than rural areas because of the 
urban "heat island" effect. Buildings, paved areas, sparse tree canopy, and lack of 
water in an urban area contribute to the higher temperature. In temperate climates, 
temperatures of urban centers such as Tigard are rising by approximately 0.5°F or more 
per decade. This can have major effects on energy consumption and air quality; a study 
of Los Angeles, for example, showed that a 1-degree rise in temperature could increase 
the city's smog risk by 3% and its energy demand by 2%, adding $25 million in 
electricity costs in a single year (Wade 2000). Trees can help mitigate the heat island 
effect, and thereby reduce energy costs, by shading buildings and cooling the air 
through the evaporative process of transpiration. 
Research by the USDA Forest Service and others has shown that trees strategically 
located to shade homes can reduce air conditioning bills significantly (McPherson 
1994b). Trees reflect and absorb solar radiation before it heats the dense building and 
pavement materials of a home or office. Trees planted to the west of a building can 
significantly reduce air conditioning costs by blocking the hot afternoon sun during 
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summer. Trees located to the south or east of a building can also provide such benefits, 
though to a lesser extent. 
In the winter, trees can also help reduce energy costs associated with the heating of 
buildings. Researchers have found that trees act as windbreaks, reducing wind speed 
and resulting air infiltration by up to 50% (McPherson et al. 2002). This can reduce air 
infiltration and conductive heat loss from buildings, lowering heating costs. The density 
of the trees, species and location of tree, type of building, and the local climate 
determine the amount of wind reduction that occurs. Although both conifers and 
deciduous trees reduce wind speed, conifers tend to have a greater impact during winter 
months. 
Researchers have studied the effect of trees on energy costs in the Willamette Valley. 
Two 25-foot tall trees located on the west side of an energy efficient home (in Portland) 
were estimated to have an energy conservation savings of $18 each year for cooling (for 
the 15% of homes that use air conditioning) and $7 for heating (McPherson et al. 2002). 
Two trees thus resulted in a combined savings of $25, which represented a 4% 
reduction in annual heating and cooling costs. 
Reduced energy needs for air conditioning or heating will mean that local power plants 
are not required to produce as much electricity or gas energy, and this conserves fossil 
fuels and reduces pollution, including carbon emissions. By providing shade over roads, 
sidewalks, park and school buildings and parking lots, trees in natural areas reduce the 
urban heat island effect. Removal of these resources can have significant adverse 
effects on energy consumption (and costs) and air quality. 
In contrast, the no additional protection option could allow for the efficient provision of 
urban facilities and services, more affordable (but less desirable) housing, a more 
compact growth form, and attendant reductions in energy consumption. However, as 
noted in the Goal 5-10 sections of this ESEE Analysis, the no additional protection option 
would have extremely negative environmental, social and economic consequences. 
Energy Conservation Consequences of Limited Protection Program 
The key features of the limited protection program that ameliorate the excesses of the 
full protection program include the following: 
• Goal 5 (Natural Resources). Rather than fully protecting all STGs, the 
Regulatory Incentives Program would not apply additional Goal 5 protection to 
several hundred acres of STGs that are already protected by Title 3 Sensitive 
Lands provisions. This greatly reduces the "leap-frog" development effect, 
because urban services no longer need to pass over undeveloped natural 
resource areas to reach buildable areas within the City. This reduction -coupled 
with the ability to construct urban facilities through STGs where necessary -
allows a compact urban form that will result in energy conservation. 
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• Goal 8 (Parks and Recreation). The Regulatory Incentives Program would 
make it possible to develop and access park and recreational facilities inside the 
Tigard City Limits. In natural areas, trails, access roads and parking areas would 
be allowed with mitigation, thus allowing area residents the opportunity to walk, 
bicycle, or drive to local park and recreational facilities, with attendant energy 
savings. 
• Goal 9 (Economy). The Regulatory Incentives Program could further limit the 
supply of industrial and commercial land available for development, thus limiting 
(a) local shopping and service opportunities, and (b) industrial jobs. Therefore, 
it is important for the City to adopt a policy to monitor and determine the effect 
of the limited protection program on the employment land supply. From an 
energy conservation perspective, it is import to continue to provide convenient 
access to local shopping and service destinations and employment, thus 
increasingly the likelihood that people will bike or walk to work, with attendant 
energy savings. 
• Goal10 (Housing). The Regulatory Incentives Program would decrease total 
housing costs by maintaining the capacity of the buildable land supply within the 
City Limits, thereby reducing the per unit costs of providing public facilities to 
serve new housing areas, and reducing travel distances from employment to 
housing. Thus, an important consideration in maintaining an affordable housing 
supply is to maintain a buildable land supply near the urban center, which has 
the effect of reducing the need to drive single-occupancy vehicles with attendant 
energy savings. 
• Goal 11 (Public Facilities). The Regulatory Incentives Program would allow 
public facilities to be routed through STGs, which would decrease energy 
otherwise needed to construct and maintain more dispersed public facilities. 
Emergency services would be less expensive to provide, because fire, police, and 
ambulances could serve a more concentrated area, thus consuming less energy. 
The effect of this form of concentrated development would be to marginally 
decrease energy costs associated with the provision of key public facilities and 
services. 
• Goal 12 (Transportation). As noted in the Goal 12 discussion, the limited 
protection program facilitates implementation of the TSP possible. The TSP calls 
for a multi-modal, interconnected systems of streets, pedestrian and bicycle 
facilities, and transit facilities. If the TSP were not implemented, people would 
be more reliant on SOVs, there could be an increase in out-of-direction travel, 
and energy consumption would increase dramatically. 
• Goal14 (Urbanization). Finally, the Regulatory Incentives Program would 
result in a more compact urban form, which would concentrate housing, jobs, 
and parks, and force less reliance on SOVs. 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 3. Tigard ESEE Analysis 
Prepared by Winterbrook Planning 
November 2011 
City ofTiganl Urban l'orcstry C()(k Rn isions I \'olume II I 2'! -1 
Page 3-52 
The limited protection program also maintains or improves upon the positive energy 
conservation effects of the full protection option. By protecting STGs near urban 
development, there will be a consequent reduction in summer air conditioning and 
winter heating costs and a reduction in the urban "heat island" effect. 
Goal 13 Conclusion 
By protecting STGs through regulatory incentives, the limited protection program 
achieves most of the positive energy consequences of the full protection option while 
enhancing energy conservation by encouraging a compact urban form and efficient 
provision of public facilities and services. The limited protection program achieves an 
appropriate balance between energy and STG conservation. 
Goal14: Urbanization 
Goal 14 reads as follows: 
To provide for an orderly and efficient transition from rural to urban 
land use, to accommodate urban population and employment inside 
urban growth boundaries, to ensure efficient use of land, and to 
provide livable communities. 
ESEE Relationship to Goal14 
Goal 14 is designed to ensure a long-term supply of buildable land to meet housing, 
population and livability (open space) needs within UGBs. Growth management policies 
are designed to ensure orderly and efficient provision of public facilities and services (as 
does Goal 11), and to maximize land use efficiency and livability within urban areas. 
Metro and Tigard have adopted a growth management program that meets these 
objectives. Metro has determined that there is sufficient buildable land within the 
regional UGB to meet long-term growth needs. Maximum efficiency of land use is 
assured by implementation of minimum density standards and requiring an urban level 
of services prior to or in conjunction with urban development. As discussed in the Goal 
9 section of this ESEE Analysis, the one area where Tigard's growth management 
program may have been less effective is ensuring adequate choice among suitable 
employment sites. 
ESEE Consequences of Full and No Protection Options for Growth 
Management 
The ESEE consequences of the full and no additional protection option on the 
effectiveness of Tigard's growth management program were analyzed in the Goal 9 
through 13 sections of this ESEE Analysis. Basically: 
• The full protection option has the effect of marginally reducing land use and 
public facilities efficiency, increasing housing costs, decreasing job potential, and 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 3. Tigard ESEE Analysis 
Prepared by Winterbrook Planning 
November 2011 
Ci ty of Tigard Urban Forestry Code ReYisions I Volume II I 295 
Page 3-53 
decreasing transportation connectivity. These factors combine to increase 
energy consumption. 
• The no additional protection option would mean that the positive ESEE 
consequences associated with providing incentives to protect at least some of 
the 124.5 STG acres located outside of Title 3 Sensitive Lands would be lost. 
ESEE Consequences of Limited Protection Program for Growth 
Management 
The limited protection program complements and improves Tigard's growth 
management program in the following ways: 
• The Tree Grove Assessment precisely maps STGs in relation to other protected 
natural resources and hazards, thus increasing certainty in the land development 
and urbanization processes. 
• Draft Chapter 18.790.050 provides clear and objective standards for mapping 
and protecting STGs through density transfer and adjustments to dimensional 
zoning standards -without loss of residential development capacity. 
• This chapter also clarifies the standards under which public facilities and services 
necessary to support urban development will be permitted within STGs, thus 
creating even greater certainty in the land development and urbanization 
processes. 
However, there are two potential adverse economic consequences associated with the 
limited protection program: 
1. Under TDC 18.790.050(X), buildable residential land that is protected through 
regulatory incentives would no longer be subject to minimum density standards. 
Although in most cases developers prefer to maximize residential densities, some 
large-lot single-family developers may take advantage of this provision, the 
likelihood that residential capacity in Tigard would significantly decrease is small. 
2. Under TDC 18.790.050(X), ifthe Regulatory Incentives Program is too successful 
in protecting STGs on buildable employment land, Tigard would have an 
inadequate supply of building commercial and industrial land under most EOA 
development scenarios. 
To address these two potential adverse economic consequences, Winterbrook 
recommends that the City amend its comprehensive plan to include policies to monitor 
the effects of the Regulatory Incentives Program and to adjust the supply of buildable 
residential and employment land as necessary to maintain Goal 9 and 10 compliance. 
Overall, the ESEE consequences of the proposed Regulatory Incentives Program are 
positive and avoid the adverse ESEE consequences associated with the full and no 
additional protection options. 
Goal14 Conclusion 
The positive ESEE consequences of Tigard 's growth management program and limited 
Goal 5 protection program are addressed in detail in previous sections of this ESEE 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 3. Tigard ESEE Analysis 
Prepared by Winterbrook Planning 
November 2011 
City of Tigard Urban l'orcstry Code RcYisions I Volume II I 296 
Page 3-54 
Analysis. The limited protection program builds upon and strengthens the positive ESEE 
consequences of the growth management program. 
Statewide Planning Goal Conclusion 
The Tigard ESEE Analysis supports the CAC's recommendation to amend the Tigard 
Development Code (TDC Chapter 18.790.050 Flexible Planting and Preservation 
Standards) to include objective density transfer provisions coupled with relaxed 
dimensional standards to encourage STG preservation - while maintaining development 
potential on buildable land. 
The ESEE Analyses reaches following basic conclusions regarding the appropriate level 
of STG protection: 
A. Full protection of all 70 STGs would prohibit all conflicting uses and activities 
on 544 acres. This would mean: 
a. Elimination of 124.5 buildable acres from the City's residential and 
employment lands inventory, and 
b. Tightening of existing Sensitive Lands regulations to prohibit all 
conflicting uses on STGs - including public facilities such as trails and 
utilities. 
This extreme regulatory approach would have positive environmental 
consequences for the natural resource, but seriously adverse economic and 
social consequences on property owners (in terms of reduced property values) 
and the community at large. Housing and public facilities costs would likely 
increase, transportation and public facilities connectivity would likely decrease, 
and employment opportunities would be lost. 
B. No additional protection (beyond Tigard's existing Sensitive Lands 
regulations) would likely result in the loss of 124.5 STG acres to conflicting 
residential and employment uses. As documented in Section 3 of the ESEE 
Analysis, urban forests provide a wide range of economic, social, environmental 
and energy conservation benefits to existing and future Tigard residents and 
employees. The no additional protection option would have adverse 
environmental and social consequences and would be inconsistent with clear 
policy direction in the Tigard Comprehensive Plan and the adopted UFMP. 
C. The Regulatory Incentives Program (the proposed limited protection 
program recommended by the CAC) provides automatic density transfer and 
regulatory relief that is likely to protect about half of the threatened STGs 
without loss of development potential on buildable land. Chapter 4 shows four 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 3. Tigard ESEE Analysis 
Prepared by Winterbrook Planning 
November 2011 
City of Tigard Urban Forestry Code ReYisions I Volume II I 297 
Page 3-55 
development scenarios that illustrate how this program could work in practice. 
The limited protection program has positive economic, social, environmental and 
energy consequences - because property rights and STGs can be protected 
without loss of potential housing units or jobs and without compromising 
transportation connectivity or the efficient provision of public facilities. 
The proposed Regulatory Incentives Program (limited protection program) maintains 
most of the environmental values described in the Tree Grove Assessment without 
sacrificing important community values associated with social equity, wildfire protection, 
park development, industrial employment opportunities, affordable housing, the efficient 
provision of public facilities and services, and compact urban growth form. As a result 
of this ESEE Analysis the proposed Regulatory Incentives Program would provide limited 
protection for STGs with buildable land outside of Title 3 Sensitive Lands areas -
approximately 23% (124.5 acres) of the STGs within the Tigard City Limits. 
Goal 1 Conclusion 
Because Tigard citizens have been notified and provided the opportunity to be involved 
in all phases of the Tree Grove Protection Project, the Goal 5 amendments resulting 
from this project comply with Statewide Planning Goal 1, Citizen Involvement. Citizen 
comments related to the Limited Protection Program (Draft Regulatory Incentive 
Program) will be considered through the public hearing process prior to adoption of the 
Goal 5 program the final ESEE Analysis. 
Goal 2 Conclusion 
For the reasons stated above, the Tree Grove Assessment provides an adequate factual 
base, this ESEE Analysis demonstrates that alternative programs were considered and 
that regional programs have been considered, and the UFMA provides ultimate policy 
direction that is implemented consistently and effectively by the proposed Regulatory 
Incentives Program. For these reasons, the Tigard Tree Grove Project complies with 
Statewide Planning Goal 2, Land Use Planning. 
Goal 5 Conclusion 
The proposed Regulatory Incentives Program (limited protection program) maintains 
most of the environmental values described in the Tree Grove Assessment without 
sacrificing important social values associated with social equity, wildfire protection, park 
development, industrial employment opportunities, affordable housing, the efficient 
provision of public facilities and services, and compact urban growth form. As a result 
of this ESEE Analysis the proposed Regulatory Incentives Program would provide limited 
protection for STGs with buildable land outside of Title 3 Sensitive Lands areas -
approximately 23% (124.5 acres) of the STGs within the Tigard City Limits. 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 3. Tigard ESEE Analysis 
Prepared by Winterbrook Planning 
November 2011 
City of Tigard Urban Forestry Code Re,·isions I \'olume I I I 298 
Page 3-56 
Goal 6 Conclusion 
Both the full protection option and the proposed limited protection program complement 
existing City, County, and State air, land, and water resource quality programs. When 
compared with the no additional protection option, both the full and limited protection 
programs have substantial positive ESEE consequences. 
Goal 7 Conclusion 
Existing Sensitive Land regulations protect STGs within Title 3 areas from most types of 
conflicting uses. The proposed Regulatory Incentives Program (limited protection 
program) applies outside Title 3 Sensitive Lands and provides an additional level of 
protection for tree groves on "buildable lands." These provisions have positive 
environmental consequences because they reinforce existing provisions that protect Title 
3 Sensitive lands on a limited basis. The proposed TDC urban forest amendments that 
implement the Tree Grove Regulatory Incentives Program complement existing Goal 7, 
Natural Hazards, regulations by encouraging tree preservation with attendant erosion 
and flood control benefits. 
Goal 8 Conclusion 
The proposed STG Regulatory Incentives Program, as implemented by draft 
amendments to TDC Chapter 18.790 Urban Forestry, will have the effect of augmenting 
the City's park and open space system. The limited protection program avoids the 
extremes of full protection (i.e., nature parks that no one can use) on the one hand, and 
no additional protection (i.e., unrestricted development and loss of STGs) on the other. 
Therefore, the proposed legislative changes comply with Goal 8, Recreational Needs. 
Goal 9 Conclusion 
Tigard has a very limited supply of buildable industrial and commercial land. /!Tigard 
were to protect all of the STGs on employment land, the City would be unable to meet 
employment land needs identified in the EOA. The setback and height incentives of the 
proposed Regulatory Incentives Program are unlikely to result in the actual protection of 
more than 10% of STGs on buildable industrial and commercial land. Even under this 
limited protection program, Tigard will still have a shortage of industrial land in all three 
of the EOA's development intensity scenarios, and a shortage of commercial land in all 
but the "efficient" scenario. Thus, the economic consequences of both the full 
protection and the limited protection options could be adverse. If the Council decides to 
encourage STG protection on employment land, Tigard planning staff should monitor the 
effectiveness of the STG protection program and, if actual buildable acreage falls below 
identified 20-year need, the City should amend its comprehensive plan to ensure a 
sufficient supply of buildable land for the 20-year planning period. 
Goal 10 Conclusion 
The proposed STG Regulatory Incentives Program will help to achieve the economic, 
social, and environmental values of the Tigard Comprehensive Plan and UFMP as applied 
to urban residential neighborhoods. This program - which is based on clear and 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 3. Tigard ESEE Analysis 
Prepared by Winterbrook Planning 
November 2011 
City of Tigard Urban Forestry Code Rc1·isions I Volume II I 299 
Page 3-57 
objective density transfer standards- avoids the extremes of the full protection option 
while protecting an estimated 50% of STGs on buildable land in Tigard. 
Goal 11 Conclusion 
The proposed Tree Grove Regulatory Incentives Program ensures that Tigard can 
continue to provide key public facilities and services necessary to support planned urban 
growth in a timely and efficient manner. This Goal 11 requirement is underscored by the 
policies of the Tigard Comprehensive Plan, and serves as the cornerstone for managing 
urban growth within the Tigard City Limits. There would be negative ESEE consequences 
for allowing public facilities to be constructed without restriction, or for prohibiting public 
facil ities construction and maintenance in all protected natural resource areas. 
Goal 12 Conclusion 
By allowing for the maintenance and expansion of existing transportation facilities, and 
the improvement of planned facilities with mitigation, adverse ESEE consequences are 
minimized. 
Goal 13 Conclusion 
By protecting STGs through regulatory incentives, the limited protection program 
achieves most of the positive energy consequences of the full protection option while 
enhancing energy conservation by encouraging a compact urban form and efficient 
provision of public facilities and services. The limited protection program achieves an 
appropriate balance between energy and STG conservation. 
Goal14 Conclusion 
The positive ESEE consequences of Tigard's growth management program and limited 
Goal 5 protection program are addressed in detail in previous sections of this ESEE 
Analysis. The limited protection program builds upon and strengthens the positive ESEE 
consequences of the growth management program. 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 3. Tigard ESEE Analysis 
Prepared by Winterbrook Planning 
November 2011 
City of T igard Urban Forestry Code Rc,-isions I \'olumc II I .'.liO 
Page 3-58 
Section 4- Proposed Limited Protection (Regulatory 
Incentives) 
The Tigard City Council adopted the Urban Forest section of the Comprehensive Plan in 
2008 and accepted the Urban Forestry Master Plan (UFMP) in 2009 to help guide and 
inform an update of the City's tree and urban forestry related code provisions. The 
Urban Forestry Code Revisions project implements four goals of the UFMP. UFMP Goal 3 
is to develop a Goal 5 preservation program by amending TDC Chapter 18.790 Urban 
Forestry: 
3. Develop a tree grove preservation program (Chapter 18.790.050) 
Proposed TDC Chapter 18.790.050 Revisions 
Proposed TDC Chapter 18.790 Urban Forestry Plan includes six categories of flexible 
standards for tree planting and preservation. The first five categories are available for 
the planting and/or preservation of all trees- regardless of their location. For example, 
TDC 18.790.050.8 provides incentives for STG preservation by slightly reducing parking 
and landscaping requirements. 
The sixth category is much more robust and is available only for development sites with 
a STG that is not protected by Title 3 Sensitive Land regulations. As the title implies, 
Section 18.790.050, Flexible Standards for Planting and Preservation, provides additional 
flexibility and incentives especla//yfor STG preservation. No other sections of Chapter 
18.790 have been modified to incorporate the additional incentives. Only development 
sites with an STG identified through this Goal 5 planning process are eligible for the 
additional incentives. 
As noted below, the proposed limited protection Regulatory Incentive Program has two 
basic components: one for residential development and one for commercial/industrial 
development. 
Residential Component 
Table 18.790.1 (from draft TDC 18.790.050) provides for automatic and objective 
residential density transfer provisions that are proportional to the tree grove area that is 
fully protected (by dedication to the city, a conservation easement or similar deed 
restriction). Adjustments to sidewalk, parking, landscaping and lot size and dimensional 
standards may be permitted. 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 4. Proposed Limited Protection 
Prepared by Winterbrook Planning 
November 2011 
City of Tigard Urban Forestry Code RcYisions I Volume II I 301 
Page 4-1 
Table 18.790.1 (from draft TDC 18. 790.050) proposed Residential Incentives 
DENSlD' T RANSFER TABLE FOR P RESERVATION O F SIGNJ F lCANT T REE 
GROVE-S 
lU 
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Npt AllowGd 
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Sill l'le famih•, dupks and mulritamilr housing Pftmirred or rhe tollt)\\'in~· det•:!.lxies· 
25:f9% t1rr i'WYC' ca!lRJ;?)' prr;:;rmUioP / ?28& ;;Q, tt 1m upit 
5fl-74°·0 m:e ~·ovc>•"j•nqpyj)f"'*W'!ltjr>,l I 1.525 N · f!. roeo1n.it 
7 5~ J(IQ~·J! n:« MC!'>"l:.'Glll01~LDfC'SCJ:nltio,, I 76:3 S.{l ft ~l- uait 
SiDr•le famih·, dnp!e:s and mulrif·lmilr housing Pft mined or rhe toUowit'l' dtnfliiies· 
?5-49"/p rn"h 2lQYC' canwn 1.2't;K!J•at joq ( I 110 >Q ft l~ 
51)-7 4°/:;. tr!:C' gron; qwclCr pn;sqntjon I 7 40 SSJ t't lo1C'1- \]!ljt 
;'_5,100~_[1'&> o:rtil\' t' C!a! )WY'i' Olf ,..,.oT:U if>l) / 370 S<"o ft lM'! li(Jit 
Sir~r femily. dn1)ltx and mn!ritfnnUy hwsiru;r pP,mjntd wjrl1 uq nR.Ptr ,-f'i'n~jrr 
limi.t.. 
As shown on Table 18.790.1, if 50% of a tree grove on a given property is preserved, 
then an increase in density of 50% is permitted outright- without a formal adjustment. 
If 75% of more of a tree grove is protected, attached housing and duplexes are allowed 
in low density residential zones to facilitate density transfer. Substantial reductions in 
front, garage and sideyard setbacks, and lot width - as well as a 20% increase in 
building height - are permitted to facilitate density transfer provisions. Substantial 
variations from development standards are also permitted (25% reduction in average 
minimum lot width; 10 foot (rather than 15 or 20 foot) front yard setbacks; 33% 
reduction in side and rear setbacks; 4 foot (rather than 20 foot) garage setbacks; and 
20% increase in maximum height. 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 4. Proposed Limited Protection 
Prepared by Winterbrook Planning 
November 2011 
City of Tigard Urban Forestry Code Rc,-isions I \ 'olumc I I I 302 
Page 4-2 
Commercial/Industrial Component 
Proposed Section 18.790.050.C.3 encourages STG protection on commercial and 
industrial land when at least 50% of STG on a commercial or industrial property is 
protected; setbacks may be reduced by as much as 50% and heights may be increased 
by as much as 20% to facilitate STG preservation. Adjustments to sidewalk, parking 
and landscaping standards may be permitted to facilitate density transfer. However, 
density transfer has limited utility for commercial and industrial development types. 
STG Regulatory Incentives Scenarios 
The following drawings show four development scenarios that could result for a large 
STG located entirely on buildable residential land. Each of these scenarios would be 
permitted outright under the revised Chapter 18.790.050, Flexible Standards for Planting 
and Preservation - depending on the proportion of the tree grove that a developer 
decides to protect (either through dedication to the city or a deed restriction) on a 
property zoned R 4.5 (a single-family residential zone with a 7,500 square foot minimum 
lot size). 
In all four of these scenarios, all of the property lies outside Title 3 protected areas. 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 4. Proposed Limited Protection 
Prepared by Winterbrook Planning 
November 2011 
City of Tigard Urban l'orcstry Code Revisions I Volume II I 303 
Page 4-3 
Option 1 ,. Standard lot Subdivision 
Averoge lot Size- 75-8'500 SF- 28 Units 
No' Tree Grove Preserved 
Option 1 shows an STG entirely removed from a property - because the hypothetical 
property owner chooses to develop a standard, large-lot, single-family detached 
subdivision withouttaking advantage of Section 18.790.050, Flexible Standards for 
Planting and Preservation. 
Effective Result: The result is the same as the no additional protection option 
because none of the STG area is protected by the City's Sensitive Lands Chapter. The R-
4.5 zoning allows 28 lots on this property while providing local street connections. 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 4. Proposed Limited Protection 
Prepared by Winterbrook Planning 
November 2011 
City of TigarJ Urban l'orcstry CoJ c RcYisions I \ ' olumc II I 30-l 
Page 4-4 
Option 2 -Standard Lot Subdivision 
Average lot Size 7S-B50tJ SF - 15 Un,its 
All Tree Grove Prese~ed 
Option 2 shows a fully protected STG on a property - because the property owner 
chooses to protect 100% of the tree grove and to develop a standard, large-lot, 
detached subdivision on the remaining buildable portion of the site. The tree grove 
itself would be considered unbuildable and therefore would not be subject to regional 
minimum density standards, as provided in Section 18.790.050, Flexible Standards for 
Planting and Preservation. The remainder of the land would be subject to minimum 
density standards - but not the land covered by the STG. 
Effective Result: The result is the same as the full protection option, because the 
tree grove would be preserved in its entirety on the subject property. However, fewer 
lots would be provided because the property owner chose not to take advantage of 
density transfer provisions in Section 18.790.050. The only incentive for this type of 
development is not having to comply with regional minimum density standards that 
would otherwise apply to the property (because none of the property is subject to either 
Title 3 or Title 13 Sensitive Land regulations). 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 4. Proposed Limited Protection 
Prepared by Winterbrook Planning 
November 2011 
City of Tigard Urban Forestry Code Revisions I Volume I I I 305 
Page 4-5 
Op~tio~n J ·Standard and Small lot Subdivision' 40% of Tree Glove Preserved 
Average Lot Size · Standard 75-BSOOSF (11) · Small lot JS-4500' SF (17) 
Option 3 shows the same tree grove that is partially protected on a property - because 
the property owner chooses to take advantage of the density transfer, lot size and 
setback reduction provisions of Section 18.790.050, Flexible Standards for Planting and 
Preservation. 
Effective Result: The result is a limited protection option, because the tree grove 
would be partially preserved while allowing conflicting residential development on 60% 
of the tree grove on the subject property. In this scenario, smaller lot sizes and flexible 
dimensional standards are traded for partial tree grove protection. This scenario 
assumes that the City Engineer has not required a connecting road to the west. 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 4. Proposed Limited Protection 
Prepared by Winterbrook Planning 
November 2011 
City of 'J'igarJ Urban Forc,try Code RcYi,ion' I \ 'olumc II I .)0(> 
Page 4-6 
Option 4- Rowhouse and Small Lot Subdivision All Tree Grove Preserved 
Average Lot Size- Rowho,use 35-4500 SF (1 B)- Small Lot 45-4900SF (70) 
Option 4 shows an STG that is protected entirely on a property- because the property 
owner chooses to take advantage of the density transfer, lot size and setback reduction, 
and housing type provisions of Section 18.790.050, Flexible Standards for Planting and 
Preservation. 
Effective Result: The result is the same as the full protection option, because the 
tree grove would be preserved in its entirety on the subject property. The trade-offs are 
clear: smaller lot sizes and attached housing are necessary protect the tree grove 
without a reduction in permitted density. This scenario assumes that the City Engineer 
has agreed to waive street connectivity requirements to the northwest and west. 
City of Tigard Urban Forestry Project 
ESEE Analysis • Section 4. Proposed Limited Protection 
Prepared by Winterbrook Planning 
November 2011 
City of Tigard Urban Forestry Code Re,-isions I Volume II I 307 
Page 4-7 

n 
Q 
s., 
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Map A: Significant Tigard Tree 
Groves and Impact Areas 
70 groves 
544.1 acres _\ 
0 25 05 
' Miles 
BEEF BEND 
Impacted Taxlot 
Inventoried Tree Grove 
Tigard City Boundary 
N 
:r: 
1-
0 
'[! 
BROCKMAN 

< 0 
c 
3 
" 
Map B: Significant Tree Groves 
with Comp Plan Designations 
70 groves 
544.1 acres 
0 25 OS 
I ..d;, I 
Comprehensive Plan Designations 
- Mixed Use Central Business District 
Community Commercial 
- General Commercial 
- Neighborhood Commercial 
- Professional Commercial 
- Heavy Industrial 
Light lndustrial 
Low Density Residential 
Medium Density Residential 
Medium-High Density Residential 
- High Density Residential 
Mixed Use Commercial 
- Mixed Use Employment 
- Mixed Use Employment 1 
- Mixed Use Employment 2 
Mixed Use Residential 1 
- Mixed Use Residential 2 
Open Space 
Public Institution 
Tgord Cfiy Boundary 
lnventoned Tree Grove 
BROCKMAN 

< 0 
c 
3 
" 
Map C: Significant Tree Groves 
in Relation to Sensitive Lands 
70 gro\es 
544.1 acres 
0 25 0 5 
I ""=· I 
~ 
tr 
tr 
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Appendix A: Tigard Tree Grove Assessment Report 
City of Tigard Urban Forestry Project 
ESEE Analysis • Appendix 
Prepared by Winterbrook Planning 
November 2011 
City o f Tigard Urban Forestry Code Rc,-isions I Volume 11 I 315 
Appendix A 

City of Tigard 
Tree Grove Assessment Report 
Prepared by: 
C O MMUNITY 
RESOURCE 
PLANNING 
With 
Richard Brainerd, Carex Working Group 
November, 2010 
City o f Tigard Urban Forestry Code Revisions I Volume 11 I 317 
City of Tigard 
Tree Grove Assessment 
Table of Contents 
INTRODUCTION 1 
SUMMARY 1 
METHODS 2 
PRELIMINARY MAPPING PROCESS 2 
TREE GROVE FIELD INVENTORY METHODS 3 
INVENTORY RESULTS 6 
CONCLUSION 10 
NEXT STEPS 11 
APPENDIX A: TREE GROVE ASSESSMENT DATA SHEETS 
City of Tigard Tree Grove Assessment Page i 
City of Tigard Urban Forestry Code Re,·isiom I \'olume II I 31H 
INTRODUCTION 
Tree groves provide scenic, aesthetic, environmental an_d other functional values to the 
Tigard community. The City Council has a commitment to the community to inventory 
remaining tree groves in Tigard and to protect significant groves through an incentive-
based program. 
The purpose of the Tree Grove Assessment project is to document the location, quantity and 
quality of significant tree groves in Tigard . The project follows the inventory process outlined 
in Statewide Planning Goal 5 (natural resources) . The outcome of this work will be the 
development of policy encouraging the preservation and protection of significant groves 
through a flexible, incentive-based grove protection program. 
This report describes the methodology used to conduct the assessment and provides the 
results with summary tables and analysis. Appendix A contains the Tree Grove Assessment 
(TGA) data sheets for each tree grove. These forms include the tree grove information and 
assessment data described in the Methods section, below. 
SUMMARY 
The tree grove assessment field work was conducted within the Tigard city limits in August 
and September, 2010. 
For the purposes of this project, a tree grove is defined as a stand of trees that are 
predominantly 25 feet or more in height with contiguous canopy cover of one acre or more 
in area. Tree groves generally do not include linear plantings that are one or two trees wide 
(e.g., street trees, rows of trees along a property linet or fragmented areas, such as treed 
areas with a high proportion of the canopy broken by houses, roads, and other developed 
uses. 
Seventy (70) significant tree grove sites were identified within the Tigard city limits. The sites 
range from 1.06 to 54.40 acres, with a combined area of 544 acres. The average site size is 
7.77 acres; the median size is 3.78. 
Overall TGA scores ranged from a high of 46 (Sites 36, 71 and 101) to a low of 18 (Sites 10, 38 
and 49). The average score for all groves was 31.4; the median score for all groves was 30. A 
summary ofthe number of groves by score is presented in Graph 1. 
Winterbrook. fl anning 
) 10 5W Fourth Avenue, Suite 1 100 
F ortland, OR. 97204-
50).827 .4-4-22 • 50).827 -4-)50 (f-ax) 
City of Tigard Urban Forestry Code Rc,·isions I Volume II I 319 
Graph 1. Tree Grove Assessment Scores 
Num1ber of Groves by Score 
10 
9 
8 
7 
6 
Num ber of 5 Groves 
4 
3 
2 
1 
0 I I 
14 lb lH .W 22 24 2b 2H 2'J 30 32 34 3b 3H 40 4 2 44 4b 
Score 
METHODS 
Winterbrook used the following methods to determine the location and the relative 
quantity and quality of significant tree groves in Tigard. 
Preliminary Mapping Process 
City planning staff worked with Winterbrook to select potentially significant tree groves for 
initial review. The City used Metro tree canopy maps and GIS technology to identify tree 
groves with a canopy cover of two acres or greater. Using this criterion alone, City staff 
determined that there were 100 tree groves in Tigard, covering approximately 930 acres 
-or about 12.3% of the City's land area . 
Winterbrook then reviewed aerial photographs and boundaries of the initial100 tree 
groves to refine Metro canopy mapping. Metro's canopy mapping software does not 
always differentiate developed areas with buildings and roads, tree shadows, and other 
landscape patterns that are not trees. These developed or non-forested areas mapped 
by Metro were removed from the City's tree grove mapping. 
Next, using aerial photo interpretation and field observation, tree grove boundaries were 
refined to include tree groves with contiguous canopy cover of one acre or more; linear or 
fragmented/developed areas were generally removed from the mapped groves. This 
Tigard Tree Grove Assessment Report Page 2 
City of Tigard Urban l'orcstry Code Rc,·isions I \'olumc II I .12ll 
decision was based on City Council direction1 to concentrate on larger, cohesive tree 
groves. 
For the purposes of this study, a significant tree grove has a contiguous canopy of one-
acre or more. Groves not meeting this threshold were dropped from the inventory. In 
cases where features such as roads or development fragmented a grove into smaller 
groves of more than one acre in size, one or more new groves were created and added 
to the inventory. 
Using the updated base maps, Winterbrook then completed the field inventory. 
Tree Grove Field Inventory Methods 
Tree groves in Tigard are generally visible from public lands (e.g., parks, streets, schools). 
Many ofthe groves are within (or partially within) city parks and could be accessed on site. 
Other groves proved to be sufficiently visible from public rights-of-way, parks and trail 
systems, and other public lands. 
Winterbrook completed detailed Tree Grove Assessment forms during field visits. The data 
collected and the assessment parameters used are described below. Once the field data 
were collected, information was transferred to electronic data sheets and the functional 
assessment rankings completed . 
Survey Data 
Tree Grove Assessment (TGA) survey forms contain information on the general 
characteristics ofthe grove such as its size, location, and vegetation composition. The 
following survey data was recorded on TGA forms in the field (except as noted below). 
Grove Site#- Follows the City's grove numbering system, generally a number between 2 and 
101. 
Date- Date(s) of the field survey. 
Field Staff -Initials of field observers. 
Size- Site acreage, reflecting any site boundary amendments made in the field; this 
calculation is provided by GIS. 
1 The City Council approved this general approach at a July 20, 2010 work session. 
Tigard Tree Grove Assessment Report 
City o f Tigard Urban Forestry Code Revisions I Volume II I 321 
Page 3 
Location- Site identifiers, such as street intersections, parks or schools, or other 
characteristics to enable identification of the grove to which the TGA form pertains. 
GoalS Site? - Is any portion of the site part of a Goal 5 (Significant Habitat) site? 
Score- The cumulative total of points for the ten tree grove functional categories (see 
discussion below). Scoring was automated using Excel-based TGA forms. The range of 
potential scores for a given grove is 10 to 50 points. Those sites with the highest scores 
provide the highest number and quality of functions. 
Map- The map number for the subject grove (currently, this is same as the grove number). 
Photos- The numbers for site photographs. 
Description- General classification of forest or woodland community using National 
Vegetation Classification System (NVCS). Dominant, co-dominant and secondary tree species 
are typically noted here, as well as general understory characteristics or species. 
Field Assessments 
The assessment section of the survey focuses on the functional characteristics of the tree 
grove. Ten functional categories are evaluated and each receives a score of low (1), medium 
(3), or high (5) based on threshold factors established in each category as described below. 
The range of potential scores for a given grove is 10 to 50 points. Following is a summary of 
the ten functional categories and their assessment factors. 
Grove Maturity/ Tree size 
Scenic values tend to be a function of tree size or age. Also, mature trees are difficult or take 
a long time to replace . The primary assessment factor in this category is the percent of large 
trees (greater than 14" diameter at breast height (dbh)) in the grove. Multi-stem trees are 
evaluated by the size of the largest individual trunk at chest height. 
Grove Size 
The vitality and resilience of a grove generally increase with grove area. Scenic, natural and 
other values often increase with size as well. Based on local grove conditions, groves of 
greater than five acres are defined as large (high), groves between two and five acres are 
defined as medium, and groves of less than two acres are defined as small (low). 
Health 
This category assesses the general health and condition of a grove, including signs of dieback, 
threats, and disturbance. Threats may include infestations of invasive plants such as English 
ivy that tend to degrade forest habitat functions and values. It may also include natural 
Tigard Tree Grove Assessment Report Page 4 
City of Tigard Urban Forestry Code Rc,·isions I \'olumc II I 322 
processes, such as beaver activity, that change the hydrologic regime to alter the existing 
tree grove composition and health. 
Visibility 
Groves that are clearly visible from major streets or public open space have greater value to 
the community. Assessment factors include visibility from an arterial or local street and/or 
public or private open space. 
Screening/Buffering 
Groves may serve as land use buffers. The value of buffering or screening is a function of the 
grove size, location and nearby uses. The greatest value to the community is when the tree 
grove provides a buffer between different types of uses, primarily between 
industrial/commercial use and residential/open space uses. 
Accessibility 
Accessibility is a function of ownership (public or private) and physical features (topography, 
trail access, etc.). Public access provides more opportunity for public use and enjoyment. 
Steep terrain and inaccessible features (wetlands, dense brush) may limit or preclude 
opportunities for public use. 
Rarity 
Unusual features, such as large size, rare species, or historic/landmark values, add to 
community value. This category considers whether such features are present, and whether 
they are uncommon or unique within the City. 
Educational/Recreational Potential 
Groves with both public access and noteworthy features offer increased educational values. 
Groves with public or semi-public access and trail networks offer passive recreation values. 
Important factors include public versus private ownership and whether developed access 
exists. This category is a function of accessibility and rarity values: if either ranks low, this 
function is low; if both rank medium, this function is medium; otherwise, this function is high. 
Wildlife Habitat Value and Connectivity 
Upland tree groves can provide important habitat for terrestrial wildlife species. The size, 
location and composition of a grove are all factors influencing the quality of habitat. Larger 
groves located near or connected to other habitat areas generally provide greater habitat 
value than smaller, isolated groves. Groves with a diverse mix of species and structure (such 
as mid-canopy trees, shrubs, groundcover, and standing or downed logs) generally provide 
higher value forage, cover and nesting habitat than groves with few species or with no 
understory. 
Tigard Tree Grove Assessment Report Page 5 
City o f Tigard Urban Forestry Code Re,·isions I Volume I I I 323 
Level of Existing Development 
Groves located on undeveloped or partially developed sites offer the opportunity to protect 
groves through site planning. Groves surrounded by development tend to be more at risk. 
Comments 
The Comments section is used to make additional notes relevant to assessment, such as 
statements of overall quality, invasive species presence, land use context, unusual 
characteristics and clarifications on assessment rankings. 
INVENTORY RESULTS 
The tree grove assessment field work was conducted within the Tigard city limits in August 
and September, 2010. 
Seventy {70) significant tree groves sites were identified within the City of Tigard . The 
majority of the groves were associated with Fan no and Summer Creeks and their major 
tributaries.The sites range from 1.06 to 54.40 acres, with a combined area of 544 acres. The 
average site size is 7.77 acres; the median size is 3.78, indicating that several larger groves 
skew the average size upward significantly. The largest grove, Grove 67 on Bull Mountain, 
covers 54.4 acres. 
Overall TGA scores ranged from a high of 46 {Sites 36, 71 and 101) to a low of 18 {Sites 10, 38 
and 49). The average score for all groves was 31.4; the median score for all groves was 30. 
Most of the tree groves are composed of a mix of tree species rather than a pure stand of a 
single species. Species present may include any or all of the following: Douglas fir, ponderosa 
pine, western red cedar, bigleaf maple, red alder, Oregon ash, Oregon white oak, black 
cottonwood, and Pacific willow. 
• In areas influenced by nearby streams or wetlands, Oregon ash, red alder, Pacific 
willow, and black cottonwood are dominants, and Douglas fir and western red cedar 
are often subdominants. 
• In upland areas out of the immediate stream corridors or wetlands, dominance 
shifted to Douglas fir, bigleaf maple, and Oregon white oak, with occasional stands of 
red alder. Stands with large, open grown Oregon white oak and/or large ponderosa 
pine usually received higher scores due to the rarity of these features and their 
importance to wildlife in the Willamette Valley. 
Fifty-nine {59), or 84 percent, of the sites are located partially or entirely within Goal 5 
Significant Habitat areas. Most of these correspond to drainageways or large wetlands, and 
are in publ ic ownership. These groves are generally larger and support greater habitat 
complexity due to variation in the plant commun ity related to moisture gradients between 
Tigard Tree Grove Assessment Report Page 6 
City of Tigard Urban I 'ore, try Code RcY i, ions I \' olumc II I 324 
uplands and wetlands. Many of the larger tree groves are within the Fan no Creek corridor, 
where the presence of parks, walking trails, and other amenities enable public access. 
Table 1 summarizes key characteristics of significant tree groves within the City: their size, 
score, and dominant vegetation, along with inventory field dates visited and whether they are 
part of Goal 5 resource sites. 
Table 1. Characteristics of Significant Tree Groves 
Tree Size Score Date of Part GoalS Dominant Species I Other characteristics 
Grove# (acres) field visit resource? 
2 1.79 26 9/1/2010 Yes Oregon white oak, Oregon ash. 
Ash Creek corridor. 
3 12.47 42 9/9/2010 Yes Black cottonwood, Oregon white oak, Oregon ash. Fanno 
Creek and small tributary confluence. Woodard Park. 
8 1.74 20 9/1/2010 No Oregon ash. 
Grove interior to large residential lots. 
9 1.34 22 9/1/2010 Yes Oregon ash. 
Grove interior to residential lots. 
10 1.06 18 9/1/2010 Yes Oregon white oak, bigleaf maple, Douglas fir. 
Grove interior to residential lots. 
11 2.11 26 9/1/2010 Yes Western red cedar, bigleaf maple, Douglas fir. 
Large lots, buffering of commercial/industrial areas 
12 6.43 40 9/1/2010 Yes Western red cedar. Large open space tract behind new 
residential development. Ash Creek corridor. 
13 2.54 34 9/1/2010 Yes Douglas fir, western red cedar, bigleaf maple, red alder. 
Open space tract along Ash Creek. Abuts local park. 
14 3.06 30 9/1/2010 Yes Western red cedar, red alder. 
Ash Creek corridor crossing several large lots. 
17 1.66 42 9/9/2010 Yes Black cottonwood, Oregon oak. Scattered trees in park, 
Goal S area. Abuts Fan no Creek corridor. 
19 9.71 42 9/9/2010 Yes Black cottonwood. Large grove part of the Fan no Creek 
corridor at Englewood Park. Mapped Goal S. 
22 4.90 34 9/10/2010 Yes Oregon white oak, Oregon ash. Large tree grove, mapped 
GoalS. Contains a small grove of ponderosa pine. 
23 3.11 26 9/9/2010 Yes Douglas fir, Oregon white oak, Oregon ash. Goal S 
resource containing tributary of Fan no Creek. 
24 3.28 26 9/1/2010 Yes Oregon ash. 
Ash swale forest connected to pasture/wetland/park 
2S s.so 42 9/9/2010 Yes Oregon ash 
Large GoalS grove at Summerlake Park. 
30 9.61 34 9/9/2010 Yes Douglas fir, Oregon ash. 
Large forest with GoalS mapping. 
31 3.68 22 9/9/2010 Yes Red alder. 
Forested open space, all covered by Goal S habitat. 
32 S.81 36 9/9/2010 Yes Oregon ash, black hawthorn. Forest abutting Mary 
Woodard Elementary school. 
Tigard Tree Grove Assessment Report Page 7 
City of Tigard Urban Forestry Code Rc,·isions I Volume II I 325 
Tree Size Score Date of Part GoalS Dominant Species I Other characteristics 
Grove# (acres) field visit resource? 
33 3.79 44 9/9/2010 Yes One of 4 top scoring sites. Oregon ash. Forest in Goal 5 
area and mostly on public property- Fanno Creek Trail. . 
35 5.50 28 9/9/2010 Yes Oregon ash, black cottonwood. Public Goal 5 site with 
adjacent treed backyards. Adjoins Grove 36. 
36 30.97 46 9/9/2010 Yes One of 4 top scoring sites. Douglas fir, ponderosa pine; 
Oregon ash . Part of grove is a forested ash wetland. 
37 2.90 20 9/9/2010 Yes Oregon ash, Pacific willow. 
Pond margin. 
38 3.10 18 9/9/2010 Yes Oregon ash. 
40 8.36 34 9/9/2010 Yes Oregon ash, Oregon white oak. Large contiguous parcel 
with grove and stream corridor in private ownership. 
42 2.21 32 9/9/2010 Yes Pacific willow, Douglas fir. 
Somewhat fragmented . Jack Park. 
44 2.99 24 9/9/2010 No Oregon white oak, Oregon ash. 
Large private lots. 
45 2.57 40 9/10/2010 Yes Oregon ash, red alder. 
Mix of species, some planted, some large and small 
46 2.94 26 9/9/2010 No Douglas fir, bigleaf maple. 
Large residential lots. 
47 2.02 24 9/10/2010 Yes Oregon ash, red alder, bigleaf maple, Douglas fir. 
Grove in open space and on large lot in GS area. 
48 6.99 34 9/10/2010 Yes Red alder, bigleaf maple, western red cedar. 
Stream corridor grove. 
49 1.54 18 9/9/2010 No Oregon ash, black cottonwood . 
Large residential lots. 
51 5.91 26 9/9/2010 Yes Douglas fir, Oregon ash. 
GoalS resource mapped along backyards, few larger lots. 
Sla 12.84 26 9/9/2010 Yes Douglas fir, Oregon ash. 
Goal 5 resource mapped along backyards, few larger lots. 
52 3.27 38 9/10/2010 Yes Douglas fir, bigleaf maple, red alder, western red cedar. 
Not public but appears to be common open space. 
54 3.88 20 9/9/2010 Yes Bigleaf maple. 
Canopy connection across access road . 
55 15.71 40 9/9/2010 Yes Douglas fir. 
Goal 5 area, mostly public land. 
56 6.69 42 9/10/2010 Yes Red alder, western red cedar. Goal 5 corridor, developed 
edges, some public some private. 
56a 2.83 36 9/10/2010 Yes Red alder, Oregon ash. 
Split from 56 by a public street. 
57 20.89 40 9/9/2010 Yes Douglas fir, bigleaf maple. Larger lots some public and 
some private, all Goal 5. 
59 13.18 30 9/9/2010 Yes Douglas fir, bigleaf maple. 
Goal 5 corridor on backs of larger lots, developed edges. 
60 5.25 40 9/10/2010 Yes Red alder, bigleaf maple. Goal 5 corridor, developed 
edges, some public some private. 
Tigard Tree Grove Assessment Report Page 8 
Cit)· of Tigard Urban Forestry Code Rc,·isions I \'olumc II I .)26 
Tree Size Score Date of Part Goal 5 Dominant Species I Other characteristics 
Grove# (acres) field visit resource? 
62 2S.28 32 9/9/2010 Yes Douglas fir, black cottonwood. 
GoalS site, some buffering against Hwy 217. 
63 1.48 22 9/10/2010 Yes Douglas fir, red alder. 
Goal S corridor, developed edges. 
64 S.31 24 9/13/2010 Yes Red alder, western red cedar. 
Goal S corridor on backs of larger lots, developed edges. 
6S 13.02 44 9/10/2010 Yes Red alder, bigleaf maple. 
Goal S corridor on large lots, some public some private. 
67 S4.40 42 9/9/2010 Yes Douglas fir, bigleaf maple. Large, sprawling grove on Bull 
Mtn. Mostly large public and private lots, Goal S area. 
68 2.76 20 9/13/2010 Yes Bigleaf maple. 
Goal S area mapped on large residential lots. 
69 2.2S 24 9/13/2010 Yes Douglas fir. 
Goal S area mapped on large residential lot. 
71 39.20 46 9/9/2010 Yes One of 4 top scoring sites. Oregon ash, red alder. 
Large GS site between development and freeway. 
73 1.97 24 9/13/2010 No Douglas fir, western red cedar. 
Grove behind apartment complex 
74 3.89 29 9/9/2010 Yes Douglas fir, western red cedar, red alder, bigleaf maple. 
Parts of grove publicly owned. 
7S 24.34 38 9/10/2010 Yes Douglas fir, bigleaf maple, red alder. Long grove with 
development at edges. Some large lots, some public. 
77 2.86 28 9/13/2010 Yes Douglas fir. 
Grove crosses several large lots. 
79 2.08 22 9/9/2010 Yes Douglas fir, bigleaf maple. 
Large residential lot. 
81 3.08 36 9/13/2010 Yes Douglas fir, western red cedar, bigleaf maple. 
Grove in some public ownership. 
83 3.46 32 9/13/2010 Yes Douglas fir. 
East Butte Park & Tigard House. Park site is -3 ac. 
86 18.2S 32 9/13/2010 No Douglas fir, bigleaf maple. 
Larger contiguous patch, became 2 groves when refined . 
86a 4.12 30 9/13/2010 No Douglas fir, bigleaf maple. 
Larger contiguous patch, became 2 groves when refined . 
89 1.21 26 8/30/2010 No Douglas fir. Golf course with some backyard trees; 
canopy cover with limited understory. 
90 2.S3 22 8/30/2010 No Douglas fir, bigleaf maple. Treed backyards but in larger 
blocks that together make a grove. 
91 1.29 24 9/13/2010 Yes Douglas fir, western red cedar. 
Goal S grove on a residential lot. 
92 2.27 22 8/30/2010 No Douglas fir. 
Grove along freeway, generally linear but still fairly wide. 
93 21.1S 40 9/13/2010 Yes Douglas fir, western red cedar. Large grove, almost 
entirely contained within Goal S resource. 
9S 3.76 28 9/13/2010 Yes Douglas fir, bigleaf maple, Oregon ash, red alder. Large 
I GoalS grove contiguous~ithJualatin River greenway. 
Tigard Tree Grove Assessment Report Page 9 
City of Tigard Urban Forestry Code Rc,-isions I Volume II I 327 
Tree Size Score Date of Part GoalS Dominant Species I Other characteristics 
Grove# (acres) field visit resource? 
96 6.50 30 9/13/2010 Yes Douglas fir, bigleaf maple, western red cedar. Large grove 
comprising private open space around Copper Creek. 
97 7.08 40 8/30/2010 Yes Oregon ash, bigleaf maple. Grove mostly in Goal 5, public 
land on east side near treatment ponds. 
99 5.89 34 8/30/2010 Yes Red alder, Oregon ash, black cottonwood, willow. Two 
groves identified (99 and 99a), separated by road . 
99a 3.21 26 8/30/2010 Yes Red alder, Oregon ash, w illow. 
Area east of above site, east of 92"d Avenue. 
100 15.39 44 9/13/2010 Yes Douglas fir, red alder. 
Large Goal 5 resource site along Tualatin River. 
101 19.91 46 9/13/2010 Yes One of 4 too scoring sites. Bigleaf maple, Douglas fir. 
Entire site within GoalS resource. Part of Cook Park. 
CONCLUSION 
This Tree Grove Assessment report, together with the TGA mapping and assessment forms in 
Appendix A, document the location, quantity and quality of significant tree groves in Tigard. 
The highest scoring grove sites cluster around streams, wetlands and other areas mapped as 
Goal 5 resources. 
We conclude with a few observations: 
• The City's tree groves and other natural areas form an impressive network of open 
space and natural habitats that provide a variety of services and amenities to the 
community. 
• The largest groves generally score high, while the smallest groves are all over the 
map -there are both high and low scores in the one to five acre range (see Graph 2). 
Tigard Tree Grove Assessment Report Page 10 
CitY of Tigard Urban l'orcstry Code Rc,-isions I \' olumc II I _)2H 
' 
Graph 2. Relationship of Grove Score to Size 
Graph of Score vs Acres 
so 
4S 
40 
3S 
Cll 
30 
.... 2S 0 
u 
Vl 20 
1S 
10 
s 
0 
0 10 20 30 40 so 60 
Acres 
• large groves scored high for several reasons: 
a. intrinsic value- i.e. more habitat diversity, interspersion, scenic value, potential 
for rare features 
b. usually in public ownership- higher value for education and recreation 
c. usually within a significant habitat (Goal 5) area 
d. often within a major riparian or wetland corridor 
e. usually with good connectivity to other sites within the same corridor 
• Many tree groves are badly infested with invasive plants in the understory. In 
particular, tree groves that are in stream corridors often have dense understories of 
Armenian (Himalayan) blackberry. Other problem species include English ivy, sweet 
cherry, and English holly. Invasive species management will be an important 
consideration in the development of a conservation strategy for tree groves. 
NEXT STEPS 
The next step in the Goal 5 process will be an analysis of Economic, Social, Environmental 
and Energy consequences of different conservation strategies, which will serve as the basis 
for policy recommendations encouraging the preservation and protection of significant 
groves through a flexible, incentive-based grove protection program. 
Current local regulation generally requires that these areas be set in separate tracts during 
development, and some of those have transferred to public ownership. Consequently, some 
Tigard Tree Grove Assessment Report Page 11 
City of Tigard Urban Forestry Code Rc,·isions I Volume II I 329 
tree groves within or adjacent to wetlands, streams and floodplains have existing local 
protection. The focus of new policy will be on the groves, or portions of groves, located 
outside of these Goal 5 protected sites. The goal of the incentive-based program is to create 
a positive pull toward maintaining these groves and expanding them where desirable and 
feasible. 
APPENDIX A: 
Tigard Tree Grove Assessment Report Page 12 
City of Tigard Urban l'orcstry Code RcYisiom I \'olumc II I _"\1() 
GROVE SITE#: 2 SIZE: 1.76 acres SCORE: 26 
DATE: 9/1/2010 LOCATION: Hall Blvd/Pine MAP: 2 
FIELD STAFF: DB/AS GOAL SSITE? Yes PHOTOS: 5643 
Grove D~scripti()n .· 
., . ... ···.··•· ... ·· 
Deciduous Forest; Oregon ash -Oregon oak codominants with black cottonwood and incense cedar. 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturity/Tree size 
Scenic and natural va lues increase 
with age; mature trees arc dit1icult to >50% of trees have > 25-50% of trees have <25% of trees have > 
replace 14" dbh ./ > 14'' dbh 14" dbh 
Gro'lle size 
Vitality, resiliance of grove generally 
increases with size >5 acres in size ./ 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
pcncral condition and signs or threats, low potential threats; high dislurbance; or 
~icback , threats, disturbance disturbance ./ invasive species invasives dominate 
Visibility Visible from arterial Visible from local 
Groves clearly visible fi·om public street or public street or private Not visible from 
lands have greater value park/open space ./ common open space street or open space 
Screening/Buffering Between industrial or 
Groves may serve as land use comercial uses and Between si milar land 
buffers; depending on density, residential or open uses, or similar land No (or very limited) 
location, uses space uses ./ use characteristics buffer function 
Accessibility Some physical or 
Greater uccess pr01•ides more legal access limits; or 
opportunity l'or public usc; but Unrestricted public part public, part Privately owned or 
inappropriate on private lots access private land ./ inaccessible 
Rarity 
Unusual features (e.g., large grove or Uncommon features 
tree size, or rare species) or Rare natural or or combination of No uncommon 
histol'ical value cultural features ./ features features 
Educationai/Rec. Potential 
Accessible groyes with unusual Accessibility and Accessibility and 
features oner recreational amVor Rarity are high or Rarity are both Accessibility or 
educational values medium medium 
./ Rarity are low 
Wildlife Habitat Diverse structure, Good source of Provides few habital 
Habitat timet ions l'or terrestrial species mix; high food, cover, territory functions, minimal 
~pecies, connect ivity, diversity connectivity; lg. size 
./ for wildlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development (< I unit per acre) ./ developed surrounded 
SUB-TOTALS 0 X5 8 X3 2 X1 
TOTALS .· ,, ' ·. o ... :'. ... 24 . . .. 2 ·.· i?> .. . . . . ' .. : · . . ·:· ·' _,: .. 
.. " 
.... ·... '"'· ·.·: :·· .:·· :,; ... 
Comments: The oak component and proximity to water increase the value of this grove. The Ash Creek floodplain and 
channel have degraded vegetation and hydraulic function . Dense vegetation in the upland buffer. lnvasives heavy 
at the margins. Some buffering. 
City of Tigard Urban I 'ores try Code Re\'isions I Volume II I 331 
GROVE SITE#: 3 SIZE: 12.47 acres SCORE: 42 I 
DATE: 9/9/2010 LOCATION: Woodland Park MAP: 3 i 
FIELD STAFF: ACS GOALS SITE? Yes PHOTOS: l 
- Grov~pescription . _·. ·: · .. - ' . :i .~:· ,-_;..·.-'·.: _ .•-:::• -? .. :·.····. 
Deciduous open woodland; Park actively managed- grass, trai ls. Dominants: bl ack cottonwood, few ponderosa pine, Oregon 
white oak, Oregon ash. Shrubs: swamp rose (dom), dewberry, snowberry, red elderberry, red osier dogwood . 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturity/Tree size 
Scenic and natural va lues increase 
ll'ith age; mature trcL'S arc dillicult to >50% of trees ha1·e > 25-50% of trees have <25% of trees have> 
replace ,/ 14'' dbh > 14" dbh 14'' dbh 
Grove si1.c 
Vitali ty, resilience of grove generally 
increases with size ,/ >5 acres in size 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some clieback or Extensive dieback or 
pcncral condition and signs or threats, low potential threats; high disturbance; or 
liehack, threats, distmbancc 
-/ disturbance invasive species invasives dominate 
Visibility Visible from arterial Visible from local 
'I roves clearly visible from public street or public street or private Not visible from 
lands have greater value ,/ park/open space common open space street or open space 
Scrcening!Bu ffering Between industrial or 
Groves may serve as land use commercial uses and Between similar land 
bull'crs; depending on density, residential or open uses, or similar land No (or very limited) 
location, uses ,/ space uses use characteristics buffer function 
Accessibility Some physical or 
Greater access pr01·idcs •norc legal access limits; or 
ppportunity lor public usc; but Unrest ri cted public part public, part Privately owned or 
inappropriate on private lots access ,/ private land inaccessible 
Rarity 
Unusual features (e.g., large grove or Uncommon features 
tree size, or rare species) or Rare natural or or combination of No uncommon 
historical value cultural features ,/ features features 
Educationai/Rec. Potential 
Accessible groves with unusual Accessibility and Accessibility and 
features oiler recreational and/or Rarity are high or Rarity are both Accessibility or 
cducat ion a I values medium 
./ medium Rarity are low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
Habitat functions for tcn·cstrial species mix; high food, cover, territory functions, minimal 
pccics, connectivity, diversity connectivity; lg. size ,/ for wildlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development -/ (< I unit per acre) developed surrounded 
SUB-TOTALS 6 X5 4 X3 0 X1 
TOTA~ ·-···.·.· _ < . . ,30 . . .· .. ···. 12 , .. _ ..... 0 .· • I <:•<:.· t ........ ·.·. '· 
Comments : upland areas pa rklike -large mature oak, ash with grassy understory. Riparian corridor trees 
younger and shrub cover is heavy especia lly where tree cover is less . Some reed canarygrass along stream . 
Huge ponderosa pine snag with pileated holes. Himalayan blackberry heavy on east side of stream. 
CitY of'J'igarJ Urban Forestry CoJc Rc,·isiom I \'olume II [ .'1.'12 
GROVE SITE #: 8 SIZE: 1.74 acres SCORE: 20 
DATE: 9/1/2010 LOCATION: 65th and Evelyn MAP: 8 
FIELD STAFF: DB/AS GOAL 5 SITE? No PHOTOS: 5624-5626 
Grove Description ···• ·· ·· .. ·.· ..... · •. ::·:/· 
. ..· .............. -· ·· ·· ,. 
. ·· . ,· 
·'·. 
.. · .... ... ... ·' .. · ........... 
Moist deciduous forest dominated by Oregon ash with shrubby understory of bigleaf maple, Norway maple, European 
hawthorn , serviceberry, English ivy, Himalayan blackberry, understory impacted by invasive..~ . Appears to be a small 
drainageway mnning north to south through grove. 
Function( Characteristic HIGH MEDIUM LOW 
Grove m aturityffr ee size 
Scenic and natural values increase 
with age; mature twcs arc diflicult to >:50% of trees have > 25-50% of trees have <25% of trees have> 
cplacc 14'' dbh > 14'' dbh ./ 14" dbh 
Grove size 
Vitality, resilience of grove generally 
increases with size >5 acres in size 2 to 5 acres in size ./ < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
lrJcncral condition and signs or threats, low potential threats; high disturbance; or 
~icback , threats, disturbance disturbance ./ invasive species invasives dominate 
Visib ility Visible from arterial Visible from local 
Grows clearly visible H·om public street or public street or private Not visible from 
lands have greater value park/open space ./ common open space street or open space 
Screening/Buffer ing Between industrial or 
Grovt.'S may ser,·c as land usc commercial uses and Between similar land 
bullcrs; depending on density, residential or open uses, or similar land No (or very limited) 
location, uses space uses ./ use characteristics buffer function 
Accessib ility Some physical or 
Greater access provides more legal access limits; or 
opportunity lor public usc; but Unrestricted public part public, part Privately owned or 
inappropriate on private lots access private land ./ inaccessible I 
Ra rity I 
Unusual features (e.g., large grove or Uncommon features 
tree size, or rare species) or Rare natural or or combination of No uncommon 
historical value cultural features features ./ features 
Educationai/Rec. Potential 
Accessible groves with unusual Accessibility and Accessibility and 
features oiTer recreational and/or Rarity arc high or Rarity are both Accessibility or 
~dueational values medium medium ./ Rarity arc low 
Wildlife Habitat Di verse structure, Good source of Provides few habitat • 
Habitat functions lor tcrreslrial species mix; high food, cover, territory functions, mini mal 
~pccies , connectivity, diversity connectivity; lg. size ./ for wildli fe connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development (< I unit per acre) ./ developed surrounded 
SUB-TOTALS 0 xs 5 X3 5 X1 
TOTJ\lS ~ :~> . . ··. .. 
,• :. · .. ~ . • 0 . .,._ ······· 15 •. 5 .. . . .. .. · . · '•· . . . 
Comments: 2 lobes connected by very narrow strip with lawn understory. Many non-nat ive trees. A couple of 
undeveloped lots. Okay for songbird habitat. Water probably seasonal. 
City of Tigard Urban Fo restry Code RcYisions I Volume II I 333 
GROVE SITE#: 9 SIZE: 1.34 acres SCORE: 22 
DATE: 9/1/2010 LOCATION: Near 69th St. I Lola St. MAP: 9 
FIELD STAFF: AS GOAL 5 SITE? Yes PHOTOS: 5628-5630 
Grove Description .. : 
. . · ... •.·.·· .. 
' 
Grove is interior where lots come together. Mixed moist forest . Oregon ash, pine, giant redwood, Douglas ftr , Orego n white 
oak, bigleaf maple. 
Function( Characteristic HIGH MEDIUM LOW 
Grove matu ri ty/Tree size 
Scenic and natural values incrca~c 
with age; mature trees arc difficult tO >50% of trees have > 25-50% of trees h<we <25% of trees have > 
replace 14'' dbh ..-' > 14'' dbh 14'' dbh 
Grove size 
Vital ity, resilience of grove genera lly 
increases with size >S acres in size 2 to 5 acres in size ..-' < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
<Jenera! condi tion and signs of threats, low potential threats; high di sturbance; or 
tieback, threats, distu rbance 
..-' disturbance invasive species invasives dominate 
Visibility Visible from arteria l Visible from local 
Groves clearly visible from public street or pub I ic street or private Not visible from 
lands have greater va lue park/open space common open space ..-' street or open space 
Screening/Buffering Between industrial or 
Grove.~ may serve as land use commercial uses and Between si mi lar l<md 
buffers; depending on density, residential or open uses, or si milar land No (or very limited) 
location, uses space uses ..-' use characteri stics buffer functi on 
Accessibility Some physical or 
Greater necess pnwides more legal access limits; or 
oppor1tmity for public usc; bu t Unrestricted public part public, part Privately owned or 
inappropriate on private lots access private land ..-' inaccessible 
Rarity 
Unusualleatures (e.g., large gro,·c or Uncommon features 
tree size, or rare spccit.-s) or Rare natural or or cornbi nation of No uncommon 
historical value cu It ural features features ..-' features 
Educationai!Rec. Potential 
Access ible groves with unusual Accessibility and Accessibi lity and 
features on'cr recreational and/or Rarity are high or Rarity are both Accessibility or 
educationa l values medium medium ,/ Rarity are low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
Habitat !'unctions fi.u terrestrial species mix; high food, cover, territory functions. minimal 
species, connectivity, diversity connectivity; lg. size ./ for wildlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development (< I unit per acre) ..-' developed surrounded 
SUB-TOTALS 1 X5 4 X3 5 X1 
TOTALS •·~ · ~~-~· .. .. ·~· · ~ .. · ~ .. : ~"'-'C.:c· ·~- - I .·. ·· · ~.12 . . 5 .. .. 
- -
__ __ ._..:......._ __ .....:_"_,_:_..:....c.:...: 
-'-·-"-'-
- -· _· _ ·· :_ .. ___:__:_:_ __ : 
Comments: Some subdivision possible. Understory mix of native/non-native, not park-like. 
CitY of Tigard Urban l;orcstry Code Rc,·isions I \'olumc II I 334 
------- --- -
GROVE SITE #: 10 SIZE: 1.06 acres SCORE: 18 
DATE: 911/2010 LOCATION: South of Ventura St. MAP: 10 
FIELD STAFF: AS GOALS SITE? Yes PHOTOS: 5640 
Gr~ve [)escription 
.·,. 
.··.·... . .. · < - : < 
.. >: . : .. :·.' 
Mixed forest , most viewable between houses. Dominants: Oregon white oak, big leaf maple, Douglas fir; other trees : Oregon 
ash , black cottonwood. 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturity/Tree size 
Scenic and nalural values increase 
with age; malure 1recs arc diftlcul1 ttl >SO% of trees have > 25-50% of trees have <25% of trees have > 
replace 14" dbh ,/ > 14" dbh 14'' dbh 
Grove size 
Vilalily, resilience of grove generally 
increases wilh size >5 acres in size 2 to 5 acres in size ,/ < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
General condilion and signs of threats, low potential threats; high disturbance; or 
dicback, 1hrca1s, dislurbancc disturbance ,/ invasive species invasives dominate 
Visibility Visible from arterial Visible from local 
I'Jroves clearly visible from public street or public street or pri vale Not visible from 
lunds have gr~>alcr value park/open space common open space ,/ street or open space 
Screening/Buffering Between industrial or 
r,roves may serve as land usc commercial uses and Between similar land 
buffers; depending on dcnsily, residential or open uses, or similar land No (or very limited) 
localion, uses space uses ./ use characteristics buffer function 
Accessibility Some physical or 
Grc~lcr access provides more legal access limits; or 
ppporlunily for public usc; bul Unrestricted public part public, part Privately owned or 
-' 
inappropriate on private lots access private land ,/ inaccessible 
Rarity 
Unusual fcalures (e.g., large grove or Uncommon features 
rce size, or rare species) or Rare natural or or combination of No uncommon 
hisloric~l value cultural features ,/ features features 
Educationai/Rec. Potential 
Accessible groves with unusual Accessibility and Accessibility and 
lcalm·es offer rccrealional and/or Rarity are high or Rarity are both Accessibility or 
cduca1ional values medium medium ,/ Rarity are low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
H~bilal funct ions lor lcn·cslrial species mix; high food, cover, territory 
,/ functions, minimal 
pccics, conncclivily, diversily connectivity; lg. size for wildlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development (<I unit per acre) developed ,/ surrounded 
SUB-TOTALS 0 X5 4 X3 6 X1 
TOTALS .... · 
····~- .· > ····.0 ·>.·· .. ·. ; •·· •• ~ .. ·· .. ··· c ·· ·. J · .. · ~: 12 .·• ;( i O: < . 6 
Comments: No connectivit y; Understory not visible: likely typical res idential maintenance. 
City of Tigard Urban Forestry Code Revisions I Volume 11 I 335 
------- --·- ------- ··- ---
GROVE SITE#: 11 SIZE: 2.11 acres SCORE: 26 
DATE: 9/1/2010 LOCATION: South of Ventura near 67th MAP: 11 
FIELD STAFF: DB/AS GOAL 5 SITE? Yes PHOTOS: 5641 , 5642 
Grove Description .•··· . .. -
.. 
: 
·_ .. · .··_ ••. -_ •. · .. ·.····-··.········· > -. 
Mixed forest; western red cedar, bigleaf maple, Douglas fir with scattered Oregon white oak, red alder. Understory quite weedy, 
with English ivy, Himalayan blackberry, English holly, some nat ive understory species including thimbleberry, hazelnut, 
vine maple, sword fern. 
Function/ Characteristic HIGH MEDIUM LOW • 
Grove maturityrfrcc size 
Scenic and natumlvalues increase 
with age; mature trees arc dirficult to >50% of trees have > 25-50% of trees have <25% of trees hal'e > 
replace 14'' dbh ./ > 14'' dbh 14'' dbh 
Grove size 
Vitality, resilience of grove generally 
increases with size >5 acres in size ./ 2 lo 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
General condition and signs or threats, low potential threats; high disturbance; or 
licback, threats, disturbance disturbance ./ invasive species invasives dominate 
Visibility Visible from arterial Visible from locnl 
<Jrovcs clearly visible li'om public street or pub! ic street or private Not visible from 
lands have greater value park/open space ./ common open space street or open space 
Screening/Buffering Between industrial or 
~roves may serve as la nd usc commercial uses and Between similar land 
buncrs; depending on density, residential or open uses, or similar land No (or very limited) 
location, uses ./ space uses use characteristics buffer function 
Accessibility Some physical or 
Grc:11cr access provides more legal access limil s; or 
opportunity tor public usc; but Unrestricted public part public, part Privately owned or 
inappropriate on private lots access private land ./ inaccessible 
Rarity 
Unusual features {c.~ .• lar~e grove or Uncommon features 
tree size, or rare species) or Rare natural or or combination of No uncommon 
tistorical va lue cultural features features ./ features 
EducationaURec. Potential 
Accessible groves with unusual Accessibility and Accessibility and 
featu res oftcr recreational and/or Rarity are high or Rarity are both Accessibility or 
ducational values medium medium ./ Rarity are low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
Habilat functions lor terrestria l species mix; high food, cover, territory functions, minimal 
15pecics, connectivity, diversity connectivity; lg. size ./ for wildlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development (< I unit per acre) ./ developed surrounded 
SUB· TOTALS 1 X5 6 X3 3 X1 
TOTALS.> -. 
···--: 
..• 5 . 
· . .18 . . .. _3 ' .... . .. 
Comments: Understory quite impacted by non-nat ives. Partially developed public ownership at east end is 
National Guard- no access . Understory has diversity if natives that are threatened by invasives. Screens 
resident ial neighborhood from National Guard facility. 
City of Tigard Urban 1-'or~'try Code Rc,-i,iom I \'olumc II I _).)(, 
1 GROVE SITE#: 112 'SIZE: 
-
6.43 acres SCORE: 40 
' 
DATE: 9/1/2010 LOCATION: East of 74th, north of Ventura MAP: 12 i 
FIELD STAFF: DB/AS GOAL 5 SITE? Yes PHOTOS: 5634 
... Grove Description ... .. .. ···:· .. 
Mixed Ever-Decid Forest. Western red cedar (dom), Douglas tlr, bigleaf maple, red alder, hazelnut, Douglas spirea, 
red elderberry, Himalayan blackberry (dom). Site is adjacent to #14- seperated by road . I 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturityrrree size 
Scenic and natural values increase 
vith ugc; mature trt·cs arc dinicullto >50% of trees have > 25-50% of trees have <25% of trees have > 
replace ,., 14" dbh > 14" dbh 14'' dbh 
Grove size 
Vitality, rc~ilience or grove generally 
increases with silc ./ >5 acres in size 2 to 5 acres i 11 size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
General condil ion and signs of threats, low potential threats; high disturbance; or 
dieback, threats, disturbance 
./ disturbance invasive species invasives dominate 
Visibility Visible from arterial Visible from local 
Groves clearly visible from public street or public street or pri vale Not visible from 
lands have greater value park/open space ./ common open space street or open space I 
Screening/Buffering Between industrial or 
Groves may serve as land usc commercial uses and Between similar land 
buflcrs; depending on density, residential or open uses, or similar land No (0< ""Y l;mhod) 
location, uses space uses ./ use characteristics buffer function 
Accessibility Some physical or 
Greater access provides more legal access I imits; or 
PPIXll1unity for public usc; but Unrestricted public part public, part Privately owned or 
inappropriate on private lots access ./ pri vale land inaccessible 
Rarity 
Unusual features (e.g., large grove or Uncommon features 
tree size, or rare species) or Rare natural or or combination of No uncommon 
historical \'aluc cultural features ./ features features 
Educa tional/Rec. Potential 
Accessible gro\'es with unusual Accessibility and Accessibility and 
features offer recreational and/or Rarity are high or Rarity are both Accessibility or 
educational values medium ./ medium Rarity are low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
Habitat functions for terrestrial species mix; high food, cover, territory functions, minimal 
species, connectivity, diversity ./ connectivity; lg. size for wildlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development ,., (<I unit per acre) developed surrounded 
SUB-TOTALS 5 X5 5 X3 0 X1 
TOTAlS ; :· .: .. ·.·· 25 . _ ..... 15 . - . o . 
Comments: Ash Creek riparian corridor. Some dead matu re western red cedar, possibly from elevated 
hydrology (beavers) . Fenced but good access from 74th. Buildout along grove proceeding. Some invasives at 
margin; ivy in interior. 
City o f Tigard Urban Forc~try Code Rc,·isions I Volume II I 337 
GROVE SITE #: 13 SIZE: 2.54 acres SCORE: 34 
DATE: 9/1/2010 LOCATION: Bet/Ventura Dr. & Ventura Pl. MAP: 13 
FIELD STAFF: DB/AS GOAL 5 SITE? Yes PHOTOS: 5638, 5639 
Grove D~scription ' .. ·,. 
... · ..-.:· . :<· . 
Mixed forest. Dominants: Douglas fir, western red cedar, bigleaf maple, red alder. Also some Oregon white oak, Oregon ash. 
Understory impacted by Engl ish ivy/Himalayan blackberry but with some native shrubs and herbs. Ash Creek !lows through 
site. 
Function/ Characteristic HIGH MEDIUM LOW 
Grove mllturityffree size : 
Scenic and natural values increase 
with age; mature trees arc ditllcult to >50% of trees have > 25-50% of trees have <25% of trees have > 
replace 14'' dbh .,/ > 14" dbh 14'' dbh 
Grove size 
Vitality, resilience of grove generally 
increases with size .,/ >5 acres in size 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
General condition and signs of threats, low potential threats; high disturbance; or 
dieback, threats, disturbance disturbance ../ invasive species invasives dominate 
Visibility Visible from arterial Visible from local 
proves clearly visible 1!·01n public street or public street or private Not visible from 
lands have greater value park/open space .,/ common open space street or open space 
Screening/Buffering Between industrial or 
lrJrovcs may SC(\'C as land usc commercial uses and Between similar land 
bullers; depending on density, residential or open uses, or similar land No (or very limited) 
location, uses space uses ../ use characteristics buffer function 
Accessibility Some physical or 
f'Jrcatcr access provides more legal access limits; or 
ppportunity for public usc; but Unrestricted public part public, part Privately owned or 
inappropriate on private lots access ,/ private land inaccessible 
Rarity 
Unusual features (e.g., large grove or Uncommon features 
tree size, or rare species) or Rare natural or or combination of No uncommon 
historical value cultural features ../ features features 
Educationai/Rec. Potential 
Accessible groves with unusual Accessibility and Accessibility and 
feoturcs oiler r<.'creational and/or Rarity are high or Rarity arc: both Accessibility or 
ducational values medium ,/ medium Rarity are low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
Habitat limctions for terrestrial species mix; high food, cover, territory functions, minimal 
species, connectivity, diversity ../ connectivity; lg. size for wildlife connectivity 
Existing Development Undeveloped Part ially Developed, or 
Groves with development (< l unit per acre) ../ developed surrounded 
SUB-TOTALS 2 X5 8 X3 0 X1 
TOTALS. 10 .· .... ·· J . 24 0 .. .. ,.,, . ~ ... 
Comments: Understory degraded by ivy and blackberry but hazelnut and serviceberry common. Portions on 
developed lots but large area at east end not developed. Good connectivity along stream corridor. 
City of Tigard Urban Forestry Code RcYisions I \'olumc. ll I .'138 
GROVE SITE#: 14 SIZE: 3.06 acres SCORE: 30 
DATE: 9/1/2010 LOCATION: Red Cedar & 74th MAP: 14 
I FIELD STAFF: DB/AS GOAL 5SITE? Yes PHOTOS: 5632-3, 5635 
.: Grove Description 
· ... 
;· 
· .. 
. . . . . . ·' . ... . . . . . / . .. 
Mixed coniferous/deciduous forest dominated by: western red cedar, red alder, big leaf maple. Forest located along Ash 
Creek with a large beaver pond in center. Understory shrub-dominated, impacted by Himalayan blackberry, reed canarygrass. 
herb Robet1 , escaped ornamentals. 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturity/Tree size 
Scenic ond nattu-al values increase 
with age; mature trees arc difficult to >50% of trees have > 25-50% of trees have <25% of trees have > 
rep lace 
./ 14" dbh ?.: 14"' dbh 14'" dbh 
Grove size 
Vitality, resilience ot' grove generally 
increases with size >5 acres in size ./ 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dicback or 
r.encrnl condition and signs of threats, low potential threats; high disturbance; or 
~ieback , threats, disturbance disturbance ./ invasive species invasives dominate 
Visibility Visible from arterial Visible from local 
proves clearly visible ti·om public street or public street or private Not visible from 
lands have greater voluc park/open space ./ common open space street or open space 
Screening/Buffering Between industrial or 
I<Jrovcs may serve as land usc commercial uses and Between similar land 
!buffers; depending on density, residential or open uses, or similar land No (or very limited) 
location, uses space uses ./ use characteristics buffer function 
Accessibility Some physical or 
Greater access provides more legal access limits; or 
oppot1tmity for public use; but Unrestricted pub lic part public, part Privately owned or 
inappropriate on pri,·-atc lots access private land ./ inaccessible 
Rarity 
Unusual teatures (e.g., large grove <Jr Uncommon features 
tree size, or rorc species) or Rare natural or or combination of No uncommon 
historical value cultural features 
"" 
features features 
Educational!Rec, Potential 
Accessible groves with unusual Accessibility and Accessibility and 
features offer recreational and/or Rarity are high or Rarity are both Accessibility or 
educational values medium medium ./ Rarity an~ low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
Habitat functions for tcn·estrial species mix; high food, cover, territory functions, minimal 
species, connectivity, diversity ./ connectivity; I g. size for wildlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development (<I unit per acre) ./ developed surrounded 
SUB-TOTALS 2 X5 6 X3 2 X 1 
TO'rALS / .:< :.-: 10 .. ·-~- .. · .. ·. < ,· __ • .... :. .-;: .- 18 :· .. -:'_' : 2 .. ':' >.-:·:.::: ... 
Comments: Many cedar/ash snags around pond. Very good habitat value. Good interspersion of adjacent 
internal aquatic/ri pa rian habitat. Residence with associated impacts (outbuildings, ornamentals). 
lnvasives: English ivy, Himalayan blackberry, clematis, English holly, herb Robert, English laurel. 
City o f Tigard Urban Forestry Code Re,·isions I Volume II I 339 
~·- ~·-·~ - . -
--
GROVE SITE#: 17 SIZE: 1.66 acres SCORE: 42 I 
DATE: 9/9/2010 LOCATION: Fanno Crk. @ Scholls Fy Rd MAP: 17 i 
FIELD STAFF: AS GOALS SITE? Yes PHOTOS: 5673 
. ·Grove Description .··· . 
Deciduous Forest - abuts Fan no Creek. Dominant trees are black co ttonwood and Oregon ash, also includes Paci fie willow. 
Shrub layers conta ins swamp rose, red osier dogwood, Douglas spirea, ash and cottonwood saplings. Herb layer dominated 
by reed canarygrass and willow-weed; also contains common rush, mannagr<1ss, cyperus. 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturity/Tree size 
Scenic and natural values increase 
.-ith age; malurc lrccs arc dirticult to >50% of trees have > 25-50% of trees have <25% of trees have > 
replace 14" dbh .;" > 14" dbh 14., dbh 
Grove size 
Vitality, resiliance of grove gcncmlly 
increases with size >5 acres in size / 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
General condilion and signs or threats, low potential threats; high disturbance; or 
licback, threals, disturbance disturbance .;" invasive species invasives dominate 
Visibility Visible from arterial Visible from local 
iroves clearly visib le ti·01n public street or public street or private Not visible from 
lands have greater value .;" park/open space common open space street or open space 
Screening/Buffering Between industrial or 
hrovcs may serve as land usc comercial uses and Between si mil ar land 
~utlers ; depending on densily, residential or open uses, or similar land No (or very limited) 
location, uses .;" space uses use characteristics buffer function 
Accessibility Some physical or 
Greater access provides more legal access limits; or 
ppporlunity for public usc; btn Unrestricted public part public, part Privately owned or 
inappropriale on privalc lots .;" access private land inaccessible 
Rarity 
Unusual features (e.g .. large grove or Uncommon features 
lree size, or rare species) or Rare natural or or combination of No uncommon 
historical value cultural features / features features 
Educationai/Rec. Potential 
Accessible groves wilh unusual Accessibility and Accessibility and 
lealures offer recr~'<ltional and/or Rarity are high or Rarity are both Accessibility or 
f:ducational values 
./ medium medium Rarity are low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
Habital funclions for tctTcstrial species mix; high food, cover, territory functions, minimal 
~pccics, eonncclivily, diversily 
.;" connectivity; lg. size for wildlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development .;" (< I unit per acre) developed surrollnded 
SUB-TOTALS 6 X5 4 X3 0 X1 
TOTALS:· x··· .•.. · ' 30 :· 
. I : 12. 0 '" ..... ·.:.: ·.·.· ... __ ,.-·. 
Comments: Tree grove along Fanno Creek. Under management to control invasives (Himalayan blackberry and reed 
canarygrass). Extensive replanting done in the past 5 years along trail. Diverse communities/hydrologic regime with high 
interspersion: forested, scrub-shrub, emergent, aquatic bed wetlands and open water plus adjacent uplands. 
A few ornamental trees present at margins 
Ci ty oi Tigard Urban l'orcstry Code Rc,·isiom j Volume II I 140 
-----~-- · - - -- - - - -- - - - -- - ----------- ----------- - ----------
GROVE SITE#: 19 SIZE: 9.71 SCORE: 42 
DATE: 9/912010 LOCATION: Englewood Park MAP: 19 
FIELD STAFF: 1As 1GOAL 5 SITE? 1Yes 1PHOTOS: 15669-72 
0 Grove Description 0 0.00000 00 <OO oooooo "0 
o O 
Deciduous Forest: riparian community with wetland margin~ ; dominated by black cottonwood with lesser coverage by Pacifi c 
willow, red alder, Oregon ash, western redcedar, and bigleaf maple. Mostly native understory. 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturityffree size 
Scenic and natural valu e.~ increase 
with age; mature trees arc diflicult to >50% of trees have > 25·50% of trees have <25% of trees have > 
replace 
./ 14" dbh > 14" dbh 14" dbh 
Grove size 
Vitali!>'. n:siuancc or grove genera lly 
increases with size 
./ >5 acres in size 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
lr.cnernl conditit>n and signs of threats, low potential threats; high disturbance; or 
~icback, threats, distu•·bancc 
./ disturbance invasive species invasives dominate 
Visibility Visible from arterial Visible from local 
Groves clearly visible from publ ic street or public street or private Not visi ble from 
lands have greater va lue 
./ park/open space common open space street or open space 
Screening/Buffering Between industrial or 
Groves may serve as lnnd usc comercial uses and Between similar land 
buncrs; depending on density, residential or open uses, or similar land No (or very I imited) 
location, uses space uses ./ use characteristics buffer function 
Accessibility Some physical or 
Greater access provides more legal access limits; or 
opportunity for public usc; but Unrestricted public part public, part Privately owned or 
inappropriate on private lots access ./ private land inaccessible 
Rarity 
Unusual tl:atures {e.g., large grove or Uncommon features 
t rcc size, or rare sp~ics) or Rare natural or or combination of No uncommon 
historical value cultural features ./ features features 
Educationai/Rec. Potential 
Accessible gro,·cs with unusual Accessibility and Accessibility and 
features oiler recreational amVor Rarity are high or Rarity are both Accessibility or 
educational values medium 
./ medium Rarity are low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
Habitat functions for terrestrial species mix; high food, cover, territory functions, minimal 
species, connectivity, diversity 
./ connectivity; lg. size for wildlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development ./ (< I unit per acre) developed surrounded 
SUB-TOTALS 6 X5 4 X3 0 X1 
T()"fAL5,> ,( '.:, 0oo0 0 • 0, 030 0, 0000 0·0·0·0000:0 ;o . ; I 0 0 00 12 0 0 0 0 oOOO 0 o o OOOOOOO 0 00, 00_..:-:0 0 .. 0 ::00,00:0::;"• . ... . ·· 
- - -
....:.__::__~~ 
Comments: Stream corridor with wide margins and upland buffer. Trail network runs throughout. Cedars mostly in 
upland area with Pacific waterleaf, th imbleberry, swordfern, beaked hazelnut, Oregon grape, and California dewberry; 
some cottonwood. ln the adjacent wetland, same trees but few cedars. Understory characterized by lady fern, skunk cabbage, 
slough sedge, and other typical wet species. Native plantings include ponderosa pine, Oregon oak, and Douglas fir. 
City of Tigard Urban Forestry Code RcYisions I Volume II I 341 
GROVE SITE#: 22 SIZE: 4.90 acres SCORE: 34 
DATE: 9/10/2010 LOCATION: N of North Dakota & 93rd MAP: 22 
FIELD STAFF: DB GOALS SITE? Yes PHOTOS: 533,534 
·Grove Description .. . ... 
. 
. · . . . .. . 
·""· 
Deciduous forest dominated by Oregon ash and Oregon white oak; west end is mi xed with a patch of large ponderosa pine, 
scattered Oregon white oak and Oregon ash. Understory mostly dominated by invasives, escaped ornamentals but with some 
native shrub and herb specie~; e.g., hazelnut, snowberry, dewberry, serviceberry. 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturity/Tree size 
Scenic and natural va lues increase 
with age; matun; trees arc diflicult to >50% of trees have > 25-50% of trees have <25% of trees have > 
replace 14"' dbh ,/ ::: l4"' dbh 14'' dbh 
Grove size 
Vil:dity, resilience of grove generally 
increases with size >5 acres in size ,/ 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or · Extensive dieback or 
Jenera I condition and signs of threats, low potential threats; high disturbance; or 
tieback, threats, disturbance disturbance ,/ invasive species invasives dominate 
Visibility Visible from arterial Visible from local 
Groves clearl>· visible fi-om public street or public street or pri vate Not visible from 
lands have !:reater value ,/ park/open space common open space street or open space 
Screening/Buffering Between industrial or 
Groves may serve as land use commercial uses and Between similar lar\d 
burtcrs; depending on density, residential or open uses, or similar land No (or very limited) 
local ion, uses ,/ space uses use characteristics buffer fun ction 
Accessibility Some physical or 
~·}rcatcr access provides more legal access limits; or 
1pportunity for public usc; but Unrestricted public part public, part Privately owned or 
inappropriate on private lots access private land ,/ inaccessible 
Rarity 
Unusual features (e.g., large grove or Uncommon features 
tree size, or rare species) or Rare natural or or combination of No uncommon 
1istorical '"aluc ,/ cultural features features features 
Educationai/Rec. Potential 
i\ccessible groves with unusual Accessibility and Accessibility and 
!caturcs o!li:r recreational and/or Rarity are high or Rarity are both Accessibility or 
pducat ionat values medium medium ,/ Rarity are low 
Wildlife Habitat Diverse stl\lcture, Good source of Provides few habitat 
Habitat functions tor tcn·cstria l species mix ; high food, cover, territory functions, minimal 
sp~-cics, conneclivity, diversity connectivity; lg. size ,/ for wildlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development ,/ (< I unit per acre) developed surrounded 
SUB-TOTALS 4 X5 4 X3 2 X1 
TOTALS .; ; .. 20 ' 12 . . ' 2 ··.: .• ... ·· .. · . ... ( 
Comments : Buffers residential area from Highway 217. 
City of Tigard Urban l'o rcstry Cmk Rc,·isions I \ 'olumc II I ."1 ~ 2 
GROVE SITE #: 23 SIZE: 3.11 acres SCORE: 26 i 
DATE: 9/9/2010 LOCATION: E of 68th; S of Hwy 99 MAP: 23 
FIELD STAFF: DB GOAL 5 SITE? Yes PHOTOS: 518-519 
-_~ <;rove Description ·.• .. · 
:0 0 
; , . : 
• , 0 
_. 
Mixed forest of Douglas fir, Oregon oak, and Oregon ash with diverse mix of other tree species: Scouter willow, black 
cottonwood, red alder, sweet cherry. Understory dominated by dense Himalyan blackberry and clematis. Other invasive species 
common- English holly, English hawthorn. 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturity/Tree size 
I :scenic and natural va lues increase i \'ith age; mature trees arc <litlicult to >50% of trees have > 25-50% of trees have <25% of trees have > j 
cplacc 14'' dbh ../ ~ 14'' dbh 14" dbh i 
Grove size I 
Vitality, rL-siliancc of grove generally ! l 
increases with size >5 acres in size ../ 2 to 5 acres in size < 2 acres in size i 
Health Healthy: no visible Some dieback or Extensive dieback or 
r,encral condition and signs of threats, low potential threats; high disturbance; or 
lieback, threats, disturbance disturbance invasive species ../ invasives dominate 
Visibility Visible from arterial Visible from local 
Groves clearly visible from public street or pub I ic street or private Not visible from 
lands have greater value park/open space ..( common open space street or open space 
Screening/Buffering Between industrial or 
proves may serve as land use comercial uses and Between similar land 
[butlers; depending on density, residential or open uses, or similar land No (or very limited) 
location, uses space uses ..( use characteristics buffer function 
Accessibility Some physical or 
preatcr access provides more legal access limits; or 
jopportunity lbr public usc; but Unrestricted public part public, part Privately owned or 
inappropriate on private lots access private land ..( inaccessible 
Rarity 
Unusual features (e.g. , large grove or Uncommon features 
rcc size, or rare species) or Rare natural or or combination of No uncommon 
historical value cultural features ../ features features 
Educationai/Rec. Potential 
Accessible groves with unusual Accessibility and Accessibility and 
features oll'er recreational and/or Rarity are high or Rarity are both Accessibility or 
educational values medium medium ../ Rarity are low ' 
Wildlife Habitat Di verse structure, Good source of Provides few habitat 
Habitat functions tor terrestrial species mix ; high food, cover, territory functions, minimal 
pecics, connectivity, diversity connectivity; lg. size 
../ for wildlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development ../ (< I unit per acre) developed surrounded 
• 
SUB-TOTALS 1 X5 6 X3 3 X1 • 
TOTAlS ········: ·.·.· 0 •• s . 18 .·· ... ' .3 . .. .. 0 ... 0 0 0 ••• ..... ;".. .... •• ... __ ·; 0 0 o' 0 
'· 
• ·',,#' . ~ .. " -
Comments: Grove includes riparian corridor of Red Rock Creek. Some nice oaks and large Douglas fir, but understory 
is totally dominated by invasives. Distant views from 1-5, Hwy 99. 
City of Tigard Urban Forestry Code RcYisio ns I Volume II I 343 
GROVE SITE #: 24 SIZE: 3.28 acres SCORE: 26 
DATE: ., 9/1/2010 LOCATION: 89th and Thorn Street MAP: 24 
FIELD STAFF: DB/AS GOAL 5 SITE? Yes PHOTOS: 5644 
. Grove Description ; ·.• .· ... ·· ... ·. . . 
· _c_ 
Deciduous forest dominated by Oregon ash, some biglcaf maple. Ash swale forest with weedy understory. Himalayan 
blackberry on the periphery. Adjacent to and clearly visible from Highway 217. 
I 
Function/ Characteristic HIGH MEDIUM LOW I 
Grove maturity/T1·ce size 
Scenic and natural vnlucs incrcnsc 
with ngc; mature trees arc di llicull to >50% of lrces have > 25-50% of trees have <25% of trees have > 
replace 14"dbh ./ > 14'' dbh 14" dbh 
Grove size 
Vitnlity, rcsiliancc or grove generally 
increases with size >5 acres in size ./ 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
jenera I condition and signs of threats, low potential threats; high disturbance; or 
licbnck, threats, disturbance disturbance ./ invasive species invasives dominate 
Visibility Visible from arterial Visible from local 
Groves clcnrly visible from puhlic street or public street or private Not visible from 
lands have greater value 
./ park/open space common ~e_en space street or open space 
Screening/Buffering Between industrial or 
!Groves may serve as land tosc comercial uses and Between similar land 
buffers; depending on density, residential or open uses, or simila r land No (or very limited) 
locaL ion, uses space uses ./ use characleristics buffer function 
Accessibility Some physical or 
!Greater access provides more legal access limits; or 
opportunity tor public usc; but Unrestricted public part public, part Privately owned or 
inappropriate on private lots access private land ./ inaccessible 
Rarity 
Unusual features (e.g., large grove or Uncommon features 
tree size, or rare species) or Rare natural or or combination of No uncommon 
historical value cultural features features ../ features 
Educationai/Rec. Potential 
Accessible groves with unusual Accessibility and Accessibility and 
features otTer recreational and/or Rarity are high or Rarity are both Accessibility or 
xlucational values medium medium 
./ Rarity are low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
Habitat fimctions for terrestrial species mix; high food, cover, territory functions, minimal 
pccics, connectivity, diversity connectivity; lg. size 
./ for wildlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development (<! unit per acre) ./ developed surrounded 
SUB-TOTALS 1 X5 6 X3 3 X1 
TOTALS /<. 
.--..:-. . .. ·· 5 ..••. ,. ,:~.;'- ....... : .... 18 . -: .· .• ·' 3 ........ 
Comments: Habitat connection to pasture and wetlands/pond to the north. Buffers Hwy 217 partially. 
CitY of Tigard Urban l'orcstry Code RcYisiom I \'o lumc II I _)44 
GROVE SITE #: 25 SIZE: 5.50 acres SCORE: 42 
DATE: 9/9/2010 LOCATION: Summerlake Park MAP: 25 
, FIELD STAFF: AS GOAL 5 SITE? Yes PHOTOS: 5674-5 
: Grove Descr~ption '. . .· 
.. 
Mixed forest. Low areas support a Oregon ash I reed canarygrass-dominated swale community. Higher ground is characterized 
by Douglas fi r, with beaked hazelnut, snowberry, Saskatoon serviceberry, English hawthorn, California dewberry, swordfern, 
thimbleberry, and oceanspray. 
Function! Characteristic HIGH MEDIUM LOW 
Grove maturity/Tree size 
Scenic and natural values inc•·case 
with age; mature trees arc dillicullto >50% of trees have > 25-50% of trees have <25% of trees ha1·e > 
replace 14" dbh ./ > 14" dbh 14" dbh 
Grove size 
Vitality, resi linncc of grove general ly 
increases with size 
./ >5 acres in size 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
!General condition and signs of threats, low potential threats; high disturbance; or 
dieback, threats, disturbance disturbance ./ invasive species invasives dominate 
Visibility Visible from arterial Visible from local 
Groves clearly 1•isible !rom public street or public street or private Not visible from 
lands have greater va lue 
./ park/open space common open space street or open space 
Screening/Buffering Between industrial or 
Groves may serve as land usc comercial uses and Between similar land 
I buflcrs; depending on density, residential or open uses, or similar land No (or very limited) i location, uses space uses ./ use characteristics buffer function I 
Accessibility Some physical or : 
'lreatcr aC\.-ess provides more legal access limits; or 
ppportunity for public usc; but Unrestricted public part public, part Privately owned or 
inappropriate on private lots 
./ access [private land inaccessible 
Rarity 
Unusual features {e.g., large grove or Uncommon features 
tree size, or rare species) or Rare natural or or combination of No uncommon 
ristorical value cultural features ./ features features i 
EducationaliRec. Potential 
I \ccessible groves with unusual Accessibility and Accessibility and 
features offer recreational and/or Rarity are high or Rarity are both Accessibility or 
f:ducational va lues 
./ medium medium Rarity are low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
Habitat l\111ctions tor terrestrial species mix ; high food, cover, territory functions, minimal 
JlL"Cies, connectivity, diversity 
./ connectivi ty; lg. size for wildlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development ./ (<I unit per acre) developed surrounded I 
SUB-TOTALS 6 X5 4 X3 0 X1 ! 
TQTALS .; < · ·.·· 
' . 
. 30 : .~ ~ '/ · .. 12 .·· ... .... ·. o. :•··. ) ... · . . · :.·.·.·· 
Comments: Some invasives- Himalyan blackberry, English holly, English ivy. Some areas in active use (play structures, 
ornamental understory, trails throughout). Strong chemical odor nearby. Big fir grove. Noxious weed removal in some areas. 
City of Tigard Urban Forestry Code ReYisioris I Volume II I 345 
GROVE SITE #: 30 SIZE: 9.61 acres SCORE: 34 
DATE: 9/9/2010 LOCATION: 72nd, west of Atlanta MAP: 30 
FIELD STAFF: DB GOAL 5SITE? Yes PHOTOS: 520 
Grove Description ·. · .. :· ·-· .. ·. ' :.> 
..... . ''· 
··' 
.. ·;.. . . · ·: . ... 
Mixed forest dominated by Douglas fir , Oregon ash, large black cottonwood and a few Oregon oak scattered . Understory 
overrun by invasives: Himalayan blackberry, English ivy, English hawthorn, Norway maple, clematis, and escaped ornamenal 
species. 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturityffrce size 
Scenic and natural values increase 
with a!;c; mature trees are diflicull to >50% of trees have > 25-50% of trees have <25% of trees have > 
replace 14" dbh ,/ > 14'' dbh 14'' dbh 
Grove size 
Vitnlity, rcsiliancc or grove generally 
increases with size ,/ >5 acres in size 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dicback or 
General condition and signs or threats, I ow potential threats; high disturbance; or 
liehack, threats, disturbance disturbance invasive species ,/ invasives dominate 
Visibility Visible from arterial Visible from local 
proves clearly visible ii·om public street or public street or private Not visible from 
lands have 1,\rcatcr value ,/ park/open space common open space street or open space 
Screening/Buffering Between industrial or 
p roves may serve as land usc comercial uses and Between similar land 
bufl'crs; depending on density, residential or open uses, or similar land No (or very limited) 
location, uses space uses ,/ usc characteristics buffer function 
Accessibility Some physical or 
Greater access provides more legal access limits; or 
opportunity for public usc; hut Unrestricted public part public, part Privately owned or 
inappropriate on private lots access ,/ private land inaccessible 
Rarity 
Unusual features (c.!,\., Jaq;c grove or Uncommon features 
tree si:~.c, or rare species) or Rare natural or or combination of No uncommon 
historical value cu I tural features ,/ features fea tures 
Educational/Rec. Potential 
Accessible groves with unusual Accessibility and Accessibility and 
fea tures o!l'cr recreational andlor Rarity are high or Rarity are both Accessibility or 
•ducat ional values medium ,/ medium Rarity are low 
Wildlife Habitat Diverse stmcturc, Good source of Provides few habitat 
Habitat functions for teiTCStriul species mix; high food, cover, territory functions, minimal 
·pecics, connectivity, diversity connectivity; lg. size ,/ for wildlife connectivity 
Existing Development Undeveloped Partially Developed , or 
Groves with development ,/ (< I unit per acre) developed surrounded 
SUB-TOTALS 3 X5 6 X 3 1 X 1 
TOTAlS ·· ....... ·.• , . .. 1 5 ; 18 , ··.1 ... ·.::. 
. ··•··· . . >.' :,: 
. .. -·. 
Comments: Red Rock Creek flows through this tree grove. Access is limited- no trails or access points. Connectivity to 
up- and downstream habitats is impaired by roads. 
Ciry of Tigard Urban l'orcstry Code RcYisions I \ 'olumc II I 34(> 
I GROVE SITE#: 31 SIZE: 3.68 acres SCORE: 22 
DATE: 9/9/2010 LOCATION: Ashbury, south of Tallwood MAP: 31 
FIELD STAFF: AS GOALS SITE? Yes PHOTOS: 520 
... : Gr<.we pescription 
.: .. :: . · . ... . . "' :.•:> . .-:.':,: 
. .. ... . · ·:.•.·:· ·: . 
Deciduous forest. Red alder dominates with lesser amounts of Oregon ash, blaek cottonwood, Scouler willow. Beaked 
hazelnut, English hawthorn and Himalayan blackberry are present in the understory. Bittersweet nightshade dominates in 
the understory. 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturityrfree si7.e 
Scenic and naturnl values increase 
\'ith age; mature trees nrc diiTicullto >50% of trees have > 25-50% of trees have <25% of trees have > 
·cplacc 14" dbh > l4"'dbh ../ 14"' dbh 
Grove si7..e 
Vitality, rcsiliancc ofgnwc general ly 
increases with size >5 acres in size ../ 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
Genernl condition and signs of threats, low potential threats; high disturbance; or 
dicback, threats, disturbance disturbance ../ invasive species invasives domi nate 
Visibility Visible from arterial Visible from local 
Groves clearl)' visible from public street or public street or private Not visible from 
lands have greater value park/open space ../ common open space street or open space 
Screening/Buffering Between industrial or 
Groves may serve as larKI use comercial uses and Between similar land 
buffers; depending on density, residential or open uses, or simi lar land No (or very limited) 
location, uses space uses ../ use characteristics buffer function 
Accessibility Some physical or 
preater access provides more legal access limits; or 
1pportunity tor publ ic usc; but Unrestricted public part public, part Privately owned or 
inappropriate on private tots access private land ../ inaccessible 
Rarity 
Unusual features (e.g., large grove or Uncommon features 
tree size, or rare species) or Rare natural or or combination of No uncommon 
~ istorical value cultural feat ures features ../ features 
Educationai/Rec. Potential 
Accessible groves with unusual Accessibility and Accessibility and 
lcaturcs otfer rccrcation:li amVor Rarity are high or Rarity are both Accessibility or 
~ducational values medium medium 
../ Rari ty are low 
Wildlife Habitat Diverse structure,· Good source of Provides few habita t 
Habitat functions for terrestrial species mix; high food, cover, territory functions, minimal 
~pecics, connectivity, diversity connectivity; lg. size 
../ for wi ldlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development (<I unit per acre) ../ developed surrounded 
SUB· TOTALS 0 X5 6 X3 4 X 1 
TOTALS ;~ . :/< 
·.:.<' .. · .... : .::·:: ) ;;O .·.·· ... ,.· :·.:·. . 18 '.: ·;·., . . .· 0: 4 . > ... .. ·.· .. · ·' ... >i: ,, ~ · . 
Comments: Residentia l lots nearly surround this grove. A small d rainage runs through the cent er of th e grove. 
City of Tigard Urban Forestry Code Revisions I Volume II I 347 
GROVE SITE #: 32 SIZE: 5.81 acres SCORE: 36 
DATE: 9/9/2010 LOCATION: Woodward Elementary MAP: 32 
. FIELD STAFF: AS GOAL 5 SITE? Yes PHOTOS: 5667 
Grove Description .: .. ,.-··.-.·· 
·.··· 
Deciduous forest along lakeshore. Edge community consists of black cottonwood, Douglas fir, black hawthorn, and Oregon 
ash. Understory is a mixture of native and invasive shrubs and herbs. 
' 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturity/Tree size 
Scenic and natural values increase 
vith age; mature trees arc diflicult 1<1 >50% of trees have > 25-50% of trees have <25% of trees have> 
replace 14 .. clbh ./ > 14'' clbh 14'' dbh 
Grove size 
Vitality, rcsilianee ol'grove generally 
increases with size 
./ > 5 acres in size 2 to 5 ac res in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
jenera! condition and signs or threats, low potential threats; high disturbance; or 
lieback, threats, disturbance disturbance ./ invasive species invasives dominate 
Visibility Visible from arterial Visible from local fa roves clearly visible n·om public street or public street or priv<~te Not visible from 
lands have greater value v" park/open space common open space street or open space 
Screening/Buffering Between industrial or 
; roves may serve as land usc comercial uses and Between simi lar land 
buffers; depending on density, residential or open uses, or similar land No (or very limited) 
location, usc$ space uses v" use characteristics buffer function 
Accessibility Some physical or 
Greater access l>rov idcs more legal access limits; or 
opportunity lbr public usc; but Unrestricted public part public, part Privately owned or 
inappropriate on pri vate lots access ./ private land inaccessible 
Rarity 
Unusual features (e.g. , large grove or Uncommon features 
tree size, or rare species) or Rare natural or or combination of No uncommon 
hist(lrical value cultural features ./ features features 
Educationai/Rcc. Potential 
Accessible groves with unusual Accessibility and Accessibility and 
features otTer recreational and/or Rarity are high or Rarity are both Accessibility or 
education a I values medium 
./ medium Rarity are low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
Habitat ltmctions for ten·estrial species mix; high food, cover, territory functions, minimal 
species, connectivity, dh·crsity connectivity; lg. size 
./ for wildlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development ./ (<I unit per acre) developed surrounded 
SUB-TOTALS 3 X5 7 X3 0 X1 
TOTALS . 15 .. I 21 0 
-· ~-- --'--- -- -~ _.o:. _· - · _ · ______ :__ . 
-
.. 
- - - --- ------ - - ---
Comments: Area near the school is receiving invasive species removal treatments and replanting. Other areas have 
moderate to heavy invasive cover. School and areas of private ownership may limit access, but there are 
other public access points including Windmill Park. 
City of TigarJ Urban Forestry Code Rev isions I \ 'olumc II I 34H 
----
GROVE SITE #: 33 SIZE: 3.79 acres SCORE: 44 
DATE: 9/9/2010 LOCATION: Fanno Creek@ Tiedeman MAP: 33 
FIELD STAFF: AS GOAL5SITE? Yes PHOTOS: 5660-1 
Grove Description . · .. 
·•····.·.· .· 
.. · . ··. 
... 
. .. 
Deciduous forest: Oregon ash grove with clustered rose and slough sedge codominant. Other constituents include red-osier 
dogwood, black hawthorn, and reed canarygrass. 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturity/Tree size 
Scenic and natural va lues increase 
with age; mature tn.-es are diHicult to >SO% of trees have > 25-50% of trees have <25% of trees have > 
replace 
./ 14"' dbh > 14" dbh 14" dbh 
Grove size 
Vitality, rcsiliancc of grove generally 
increases with size > 5 acres in size ./ 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dicback or Extensive dicback or 
General condition and signs or threats, low potential threats; high disturbance; or 
licback, threats, disturbance 
./ disturbance invasive species invasives dominate 
Visibility Visible from arterial Visible from local 
proves clearly visible lrom public street or public street or private Not visible from 
lands have greater value 
./ jparklopen space common open space street or open space 
Screening/Buffering Between industrial or 
farO\'es may serve as land usc comercial uses and Between similar land 
!buffers; depending on densi ty, residential or open uses, or similar land No (or very limited) 
location, uses space uses ./ use characteristics buffer function 
Accessibility Some physical or 
jGreater access provides more legal access limits; or 
ppportunity lor public usc; but Unrestricted public part public, part Privately owned or 
inappropriate on private lots 
./ access private land inaccessible 
Rarity 
Unusual features (e.g., lnrsc grove or Uncommon features 
rcc si7.c, or mre species) or Rare natural or or combination of No uncommon 
!historical value cultural features ./ features features 
Educational/Rcc. Potential 
Accessible groves wi th unusual Accessibility and Accessibility and 
features offer recrca1 ional amVor Rarity are high or Rarity are both Accessibility or 
ducntional values 
./ medium medium Rarity are low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
Habitat !unctions for terrest rial species mix; high food, cover, territory functions, minimal 
species, connectivity, diversity 
./ connectivity; lg. size for wildlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development ./ (<I unit per acre) developed surrounded 
SUB-TOTALS 7 X5 3 X3 0 X1 
TOTALS {>•·· .... 35 .. .· .. . ·... . ..... ·~ .. 9 .. 
.. · 0 ; >.; ,/ .·.·· ', ... •· 
Comments: Adjacent park, Grove 36, and wetland increase public and habitat values. 
City of Tigard Urban Forestry Code RcYisions I Volume II I 349 
1!GROVE SITE #: 35 SIZE: 5.50 acres SCORE: 28 
"DATE: 9/9/2010 LOCATION: 116th and Katherine MAP: 35 
FIELD STAFF: AS GOAL 5 SITE? Yes PHOTOS: 5665-6 i 
Grove Description .... · · 
.. ·. 
.. 
:" i . .-: . .. 
Deciduous forest : Dominant species include Oregon ash and black hawthorn in the tree layer and slough sedge and field 
horsetail in the understory. Other species present include English hawthorn, beaked hazelnut, clustered rose, red-osier 
dogwood, Norway maple, and bittersweet nightshade. Trees are mostly smaller. 
Function/ Characteristic HIGH MEDIUM LOW ! 
Grove maturity/Tree size 
Scenic and natural va lues increase 
with age; mature trees arc di!licult to >50% of trees have > 25-50% of trees have <25% of trees have > 
replace 14' ' dbh ./ > 14 .. dbh 14'" dbh 
Grove size 
Vitality, resilinncc of grove generally 
increases with size >5 acres in size ./ 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
General condition and signs of threats, low potential threats; high disturbance; or 
licback, threats, disturbance disturbance ./ invasive species invasives dominate 
Visibility Visible from arterial Visible from local 
Groves clearly visible from public street or public street or private Not visi ble from 
lands have greater value park/open space ./ common open space street or open space 
Screening/Buffering Between industrial or 
irovcs may scn·c as land usc comercial uses and Between similar land 
buffers; depending on density, residential or open uses, or simi lar land No (or very limited) 
location, uses space uses ./ use characteristics buffer function 
Accessibility Some physica l or 
ircatcr access provides more legal access limits; or 
1pportunity for public usc; but Unrestricted publ ic part public, part Privately owned or 
inappropriate Clll private lots access ./ private land inaccessible 
Rari ty 
Unusual features (e.g., large grove or Uncommon features 
tree size, or rare species) or Rare nat ural or or combination of No uncommon 
historical ' 'aluc cultural features featu res ./ features 
EducationaURec. Potential 
Accessib le groves with unusual Accessibility and Accessibility and 
features offer recreational and/or Rarity are high or Rarity are both Accessibility or 
ducational values medium medium ./ Rarity are low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
Habitat functions for terrestrial species mix; hi gh food, cover, territory functions. minimal 
species, connectivity, diversity connectivity; lg. size 
./ for wildlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development ./ (< I unit per acre) developed surrounded 
SUB-TOTALS 1 X5 7 X3 2 X 1 
TOTAlS . 5 
.21 ' . 2 :· .. • . .·. 
til> 
Comments: This grove is contiguous across 116th Avenue. 
City of T igard Urban l'orcstry Code Rc,·isions I \'olumc II I ."\ 511 
GROVE SITE #: 36 SIZE: 30.97 acres SCORE: 46 
DATE: 9/9/2010 LOCATION: Fanno Crk Trail@ Tiedeman MAP: 36 
FIELD STAFF: ACS GOALS SITE? Yes PHOTOS: 5662-3 
· Grove Description .. · ~ . :c· 
· ... '. 
.... >::: .·" .. ':0: 
: . 
·. ,, ' ..... ···'.:. 
Evergreen forest: Dominants: Douglas tir, ponderosa pine; nlso bigleafmaple, western red cedar. Shrubs: hazelnut (dom), 
holly, oceanspray, Oregon grape, snowberry. Herbs: English ivy {dom), sword fern , Dewey's sedge, inside-out flower, 
starflower. 
Function/ Characteristic HIGH MEDIUM LOW 
Grove matur ityrfree size 
Scenic and natural vn lucs increase 
with age; mature trees are dillicult to >50% of trees have > 25-50% of trees have <25% of trees have > 
replace 
./ 14" dbh > 14'' dbh 14" dbh 
Grove size 
Vitality, resilience of grove generally 
increases with size 
./ >5 acres in size 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
General condition and signs of threats, low potential threats; high disturbance; or 
tieback, threats, disturbance disturbance ./ invasive species invasives dominate 
Visibility Visible from arterial Visible from local 
I roves clearly visible from public street or public street or private Not visible from 
lands have grCOJtc•· value 
./ park/open space common open space street or open space 
Screening/Buffering Between industrial or 
!Groves may serve as land use commercial uses and Between similar land 
!hullers; depending on density, residential or open uses, or similar land No (or very limited) 
location, uses space uses ./ use characteristics buffer function 
Accessibility Some physical or 
lorcater access provides more legal access limits; or 
!opportunity tor public usc; but Unrestricted public part public, part Privately owned or 
inappropriate on private lots 
./ access private land inaccessible 
Rarity 
Unusual features (e.g., large grove or Uncommon features 
tree size, or rare species) or Rare natural or or combination of No uncommon 
!historical value 
./ cultural features features features 
Educationai/Rec. Potential 
Accessible groves with unusual Accessibility and Accessibility and 
features otl"er recreational and/or Rarity are high or Rarity arc both Accessibility or 
educational values 
./ medium medium Rarity are low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
Habitat !!met ions for terrestrial species mix; high food, cover, territory functions, minimal 
species, connectivity, diversity ./ connectivity; lg. size for wildlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development ./ (< I unit per acre) developed surrounded 
SUB-TOTALS 8 X5 2 X3 0 X1 
TOTALS .······.·.····· ..... . 40 .: ;. ....... / I > .6 . . ,· ·.0 .. .. 
·· ..... . ... , .. 
Comments: La rge fir/pine grove in Fan no Creek trail complex. Close to school. Ivy heavy, climbing t rees. Holly 
also heavy. Informal trails throughout but minor trash, damage. Most ly large trees but some younger t rees, 
saplings too. 
City of Tigard Urban Forestry Code RcYisions I Volume 11 I 351 
GROVE SITE #: 37 SIZE: 2.90 acres SCORE: 20 
DATE: 9/9/2010 LOCATION: Roger Hart W/C; E of 131st MAP: 37 
FIELD STAFF: ACS GOAL 5 SITE? Yes PHOTOS: 5690-2 
.•· _ Grove Description ... _ ...... · .· ·.- ....... > ·. ,. ;· ... •.>_·;·.' 
Mixed forest- Oregon ash (dom), Pacific willow (dom), Douglas fir, cottonwood, ornamental trees (silk tassel/paper birch). 
Landlocked- view over rooftops; Roger Hart W/C 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturity/Tree size 
Scenic and natural va lues increase 
wi th age; mature tree.~ arc diflicult to >50% of trees have > 25-50% of trees have <25% of trees have > 
replace 14" dbh ?.: (4" dbh ./ 14" dbh 
Grove size 
Vitality, resilience of grove generally 
increases with size >5 acres in size ./ 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
Jcncral condition and signs or threats, low potential threats; high disturbance; or 
~ieback, threats, disturbance disturbance ./ invasive species invasives dominate 
Visibility Visible from arterial Visible from local 
Groves clearly ''isiblc ii·om public street or public street or private Not visible from 
lands have greater value !park/open space common open space ./ street or open space 
Screening/Buffering Between industrial or 
Groves may serve as land usc commercial uses and Between similar land 
buflers; depending on density, residential or open uses, or similar land No (or very limited) 
location, uses space uses ./ use characteristics buffer function 
Accessibility Some physical or 
!Greater access provides more legal access limits; or 
iopportunity tor public usc; but Unrestricted public part public, part Pri vately owned or 
inappropriate on private lots access pri vale land ./ inaccessible 
Rarity 
Unusual features (e.g., large grove or Uncommon features 
tree size, or rare spcciL-s) or Rare natural or or combination of No uncommon 
historical value cultural features features ./ features 
Educationai/Rec. Potential 
Accessible groves with unusual Accessibility and Accessibility and 
features otlcr recreational and/or Rarity are high or Rarity are both Accessibility or 
·ducational values medium medium ,/ Rarity are low 
Wildlife Habitat Diverse st ructure, Good source of Provides few habitat 
Habitat timet ions for terrestrial species mix; high food, cover, territory functions, minimal 
species, connectivity, diversity connectivity: lg. size ./ for wildlife connectivity 
Existing Development Undeveloped Patti ally Developed, or 
Groves with development (< I unit per acre) ./ developed surrounded 
SUB-TOTALS 0 X5 5 X3 5 X1 
TOTAlS '/ , -.·.·.··. 
.... - 0 . · 
.. 
.··-
. -15 
.. ·: ... .. s - -.:: ; _; • < .: . 
Comments: Minimal visibility; Dominant in wetland: Pacific wi llow, red alder saplings, Douglas spirea (dam), 
Himalayan blackberry {dam), reed canarygrass (dam). 
City of Tigard Urban Forc,try Code RcYi, ions I Volume II I 352 
GROVE SITE #: 38 SIZE: 3.10 acres SCORE: 118 
DATE: 9/9/2010 LOCATION: Elmhurst & 70th MAP: 138 
FIELD STAFF: DB GOALS SITE? Yes PHOTOS: 1521,522 
• Grove Description . 
Deciduous forest with scattered Douglas fir. Dominant is Oregon ash,; some Pacific willow, Oregon white oak, Scouler willow. 
Canopy is pretty broken; entire grove lies east of 72nd. Mapped portions west of72nd too small and fragmented. 
Function( Characteristic I I HIGH I MEDIUM I I LOW 
Grove maturity/Tree size 
Scenic and natural values increase 
with age; mature trees arc dinicult to >50% of trees have > 25-50% of trees have <25% of trees have > 
replace 14" dbh ~ 14" dbh 14" dbh 
Grove size 
Vitality, resilience of grove generally 
increases with size >5 acres in size ./ 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dicback or Extensive dieback or 
icncral condition and signs of threats, low potential threats; high disturbance; or ~icback, threats, disturbance disturbance invasive species ./ invasives dominate 
![Visibility Visible from arterial Visible from local 
!Groves clearly visible from public street or public street or pri va le 
I 
INot visible from 
lands have greater value park/open space v' common open space street or open space 
.Screening/Buffering Between industrial or 
jarovcs may serve as land usc commercial uses and Between similar land 
:buffers; depending on density, residential or open uses, or simi lar land I INo (or very limited) location, uses space uses ./ use characteristics buffer function 
Accessibility Some physical or 
hrcatcr access provides onol'c legal access limits; or 
pportunity for public usc; but Unrestricted public part public, part I I Privately owned or inappropriate on private lots access private land ./ inaccessible 
II Rarity 
Unusual features (e.g., la rge grove or I ~ Uncommon features ltrt'C size, or rare species) ol' Rare natural or or combination of I INo uncommon ·1istorical value cultural features features v' features 
IIEducationai/Rec. Potential 
Accessible grol'es wi th unusual Accessibility and Accessibility and 
features otler recreational and/or Rarity are high or Rarity are both Accessibility or 
\xlucational values medium medium v' Rarity arc low 
~~~ildlifc Habitat Diverse structure, Good source of Provides few habitat 
Habitat functions for tcrrcstriul species mix; high food, cover, territory 
./ functions, minimal ispecies, connectivity, diversity connectivity; lg. size for wildlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development (< l unit per acre) ./ developed surrounded 
SUB-TOTALS 0 X 5 4 X 3 6 X 1 
TOTALS.- > • •• 0 .···· .. 1 2 .. · ......... ... ·· ... · 6 I ·· .. • ;, 
Comments : Unde rstory dom inated by invasives . 
City of'J'igard Urban Forestry Code Re,·isions I Volume II I 353 
GROVE SITE #: 40 SIZE: 8.36 acres SCORE: 34 
DATE: 9/9/2010 LOCATION: Dartmouth, S of Costco MAP: 40 
FIELD STAFF: DB GOAL 5 SITE? Yes PHOTOS: 523,524 
Grove Description 
Deciduous forest dominated by Oregon ash with a patch of slough sedge, Oregon white oak . Red Rock Creek flows through 
tree grove. There 11re ponds in center and at northeast corner. Understory with Himalayan blackberry, reed canarygrass, 
English ivy, English hawthorn 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturi tyrfree size 
Scenic ami natural value~ increase 
with age; mature trc~-s arc difficult to >50% of trees have > 25-50% of trees have <25% of trees have > 
replace 14" dbh -/ > 14" dbh 14'' dbh 
Grove size 
Vitality, resilience or grove generally 
increase.> with size 
-/ >5 acres in size 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
icncral condition and signs of threats, low potential threats; high disturbance; or 
tieback, threats, disturbance disturbance -/ invasive species invasives dominate 
Visibility Visible from arterial Visible from local 
)roves clcurly vis ible fi·om public street or public street or private Not visible from 
lands have greater va lue 
-/ park/open space common open space street or open space 
Screening/Buffering Between industrial or 
Jrovcs may serve as land usc commercial uses and Between similar land 
hullers; depending on density, residential or open uses, or similar land No (or very limited) 
location, uses space uses -/ use characteristics buffer function 
Accessibility Some physical or 
Greater access provides more legal access limits; or 
opportunity for public usc; but Unrestricted public part public, part Privately owned or 
inappropriate on private lots access private land ,/ inaccessible 
Rarity 
Unusual featu res (e.g., large grove or Uncommon features 
tree size, Ol' rare species) or Rare natural or or combination of No uncommon 
historical value cultural features ./ features features 
Educational/Rec. Potential 
Accessible ~;r~wcs with unusual Accessibility and Accessibility and 
features of'ler recreational and/or Rarity are high or Rarity are both Accessibility or 
cducat ion a I ,·a lues medium medium .( Rarity are low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
Habitat functions lor terrestrial species mix; high food, cover, terri toty functions, minimal 
pL'Cics, connecti vity, di versity -/ connectivity; Jo. size for wildlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development -/ (< I unit per acre) developed surrounded 
SUB-TOTALS 4 X5 4 X3 2 X1 
TOTALS 20 12 .. 2 
Comments: Good interspersion of habitats, understory is weedy, some use by homeless people. Open area 
to east is an old landfill. 
City of Tigard Urban l'orc>try Code Rc,·i>iom I \'olumc II I 354 
GROVE SITE #: 42 SIZE: 2.21 acres SCORE: 32 
DATE: 9/9/2010 LOCATION: Eof 124th MAP: 42 
FIELD STAFF: ACS GOALS SITE? Yes PHOTOS: none 
·. Grove Description>· · .. 
.. 
.. ·· .. •·.·· ...  ·,>.· :};-
Mixed forest dominated by Pacific willow, Douglas fir, with scattered black cottonwood and red alder. The understory 
is dominated by Himalayan blackberry and lawn grass. 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturityffree size 
Scenic and natural values increase 
with age; 111aturc trees arc dillicult to >50% of trees luwe > 25-50% of trees have <25% of trees have > 
eplace 14" dbh ..r > 14'' dbh 14" dbh 
Grove size 
Vitality, resilience of grove generally 
increases with size >5 acre in size ..r 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
jenera! condition and signs of threats, low potential threats; high disturbance; or 
dicback, threats, disturbance disturbance ..r invasive species invasives dominate 
Visibility Visible from arterial Visible from local 
Groves clearly visible from public street or public street or private Not visible from 
lands have greater value 
..r park/open s_])_ace common open space street or open space 
Screening/Buffering Between industrial or 
\)roves may serve as land use commercial uses and Between similar land 
bu rrers; depending on density, residential or open uses, or similar land No (or very limited) 
location, uses space uses use characteristics ..r buffer function 
Accessibility Some physical or 
Greater access provides more legal access limits; or 
opportunity for public usc; but Unrestricted public part public, part Privately owned or 
inappropriate on private lots 
..r access private land inaccessible 
Rarity 
Unusual features (e.g., large grove or Uncommon features 
tree si7.c, or rare species) or Rare natural or or combination of No uncommon 
1istorical value cultural features ..r features features 
EducationaVRec. Potential 
Accessible groves with unusual Accessibility and Accessibility and 
1\:nturcs otTer recreational and/or Rarity are high or Rarity are both Accessibility or 
educational values 
..r medium medium Rarity are low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
Habitat lhnctions lor terrestrial species mix; high food, cover, territory 
,/ functions , minimal 
species, connectivity, diversity connectivity; lg. size for wildli fe connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development (< I unit per acre) ..r developed surrounded 
SUB-TOTALS 3 X 5 5 X 3 2 X1 
TOTALS ;· . 1 5 . . ' .15 ··2 ... : • ·:· ....... · ......... :·:·.·· · . ..• ·:1 .. >· . .... 
Comments: Neighborhood park with small incised creek. West side managed tree grove. East side has trees 
along stream and buffer, heavy Himalayan blacberry. North of footbridge, stream corridor widens. Understory 
is mostly reed canarygrass and red alder/Paci f ic willow at edges. Douglas fir and Himalayan 
blackberry present above. 
City of Tigard Urban Forestry Code Revisions I Volume II I 355 
GROVE SITE #: 44 SIZE: 2.99 acres SCORE: 24 
DATE: 9/9/2010 LOCATION: SW of Franklin/66th MAP: 44 
FIELD STAFF: DB GOAL 5 SITE? No PHOTOS: 525 
Grove Description · 
. : 
. ; ·; T 
Deciduous oak - ash forest with widely spaced large oaks/dense young ash. Understory mostly dense Himalayan blackberry. 
Also English ivy and other invasivcs and escaped ornamentals. 
Function/ Characteristic HIGH MEDIUM LOW 
G rove maturityfrree size 
Scenic and natural values increase 
with age; mature trees arc eli nicuh to >50% of trees have > 25-50% of trees have <25% of trees have > 
replace 14" dbh > 14" dbh ./ 14'' dbh 
Grove size 
Vitality, resilience of grove genera II) 
increases with size >5 acres in size ./ 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
Jenera! condit ion and signs of threats, low potential threats; high disturbance; or 
jdieback, threats, disturbance dis turbance ./ invasive species irwasives dominate 
Visibility Visible fro m arterial Visible from local 
proves clearly visible from public street or public street or private Not visible from 
lands have greater value 
./ park/open space common open space street or open space 
Screening/Buffering Between industrial or 
!Groves may serve as land usc commercial uses and Between similar land 
butTers; depending on dens ity, residentia l or open uses, or similar land No (or very limited) 
local ion, uses space uses ./ use characteristics buffer function 
Accessibility Some physical or 
Greater access provides more legal access limits; or 
opportunity for public use; but Unrestricted public part public, part Privately owned or 
inappropriate on private lots access pri vale land ./ inaccessible 
Rarity 
Unusual features (e.g., large grove or Uncommon features 
tree size, or rare species) or Rare natural or or combination of No uncommon 
historical value cultural features ./ fea tures features 
Educational/Rec. Potential 
Accessible grO\'CS with unusual Accessibility and Accessibility and 
features oncr recreational and/or Rarity are high or Rarity are both Accessibility or 
·dueational values medium medium ./ Rarity are low 
Wildlife Habitat Diverse structure, Good source or Provides few habitat 
Habitat !\met ions lor terrestrial species mix; high food, cover, territory functions, minimal 
sp~-cies, connectivity, diversity connectivity; lg. size for wildlife ./ connecti vi tv 
Exis ting Development Undeveloped Partially Developed, or 
Groves with development (< I unit per acre) ./ developed surrounded 
SUB~ TOTALS 1 xs 5 X 3 4 X1 
TOTALS}:·· . _ '5 · .. ' '. 15 · 4 ·. ·.· j_;;_/ . -..... ·' ' .·: . . :· .i ' 
Comments: Poor con nectivity. la rge oa ks a plus but otherwise not great habitat. Buffers surrounding office/ 
warehouse area from 1-5. Note: 67th is put, narrow, gravel road . Keep the portion west of 67th as part of this 
tree grove. 
City of Tigard Urban Fore, try Code ReYi,ions I \' olume II I 356 
-~ ~~ ~~-
GROVE SITE #: 45 SIZE: 2.57 acres SCORE: 40 
DATE: 9/10/2010 LOCATION: S of Walnut & 160th MAP: 45 
FIELD STAFF: DB GOAL SSITE? Yes PHOTOS: 535,536 
·.· ·.• Grove Description ·' ·· .....•.. , ... ••·.· .......... > 
Deciduous forest dominated by Oregon ash and red alder, with scattered large black cottonwood . Understory: Shrub layer 
well developed, dominated mostly by natives- salmonberry, red-twig dogwood, scattered snags. 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturity/Tree size 
Scenic and natural values increase 
,·ith age; mature trees are dillicull to >50% of trees have > 25-50% of trees have <25% of trees have > 
replace 14'' dbh ../ > 14" dbh 14"dbh 
Grove size 
Vitality, resilience of t;rove generally 
increases with size >5 acres in size ../ 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dicback or Extensive dieback or 
fJcncral condition and signs of threats, low potential threats; high disturbance; or 
tieback, threats, disttn·bancc 
../ disturbance invasive species invasives dominate 
Visibility Visible from arterial Visible from local 
proves clearly visible !i·om public street or public street or private Not visible from 
lands have greater value park/open space ../ common open space street or open space 
Screening/Buffering Between industrial or 
Groves may serve as land usc commercial uses and Between similar land 
burtcrs; depending on density, residential or open uses, or similar land No (or very limited) 
location, uses space uses ../ use characteristics buffer function 
Accessibility Some physical or 
lrrreatcr access provides more legal access limits; or 
iopportunity for public usc; bu t Unrestricted public part public, part Privately owned or 
inappropriate on private lots 
../ access private land inaccessible 
Rarity 
Unusual features {e.g., large grove or Uncommon features 
tree size, or rare species) or Rare natural or or combination of No uncommon 
historical value cultural features ../ features features I I 
Educational/Rec. Potential I 
Accessible grov<..'S with unusual Accessibility and Accessibility and 
lcotures offer recreational and/or Rarity are high or Rarity arc both Accessibility or 
ducational values 
../ medium medium Rarity are low 
Wildlife Habitat Di verse structure, Good source of Provides few habitat 
Habitat timet ions for terrestrial species mix; high food, cover, territory functions, minimal 
·pecics, connectivity, diversity ../ connectivity; lg. size for wildlife connectivity 
Existing Development Undeveloped Partially Developed , or 
Groves with development ../ (<I unit per acre) developed surrounded 
SUB-TOTALS 5 X5 5 X3 0 X1 
TOTALS ;> 25 . ·: .·· ~ 15 ..• 0 
Comments : Riparian corridor. Derry Dell Creek flows through tree grove. Connect ivity to north somewhat 
limited by street but good structure diversity, perennial stream, native understory. 
Exceptional for the lack of exotic/invasive species. 
Cit)' of Tigard Urban Forestry Code Re,-isions I Volume II I 357 
GROVE SITE #: 46 SIZE: 2.94 acres SCORE: 26 
.DATE: 9/9/2010 LOCATION: 133rd and Walnut MAP: 46 
IIFIELD STAFF: lACS !GOAL 5 SITE? I No !PHOTOS: 15685 
.· .Grove Description .. ·.· . ·. ·. .. . 
·. - ... . , : .· .. ·.· . .. . 
.. . ··. 
. : :,:: ....... 
Mix.ed: Dominated by Douglas tir, bigleaf maple, hazelnut, dewberry. Understory has big leaf maple, red alder, westem redcedar 
saplings, bitter cherry. Himalayan blackberry, swordfern. and Engl ish ivy are dominant on the forest lloor. 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturity/Tree size 
Scenic and rwtural ,·a lues increase 
with n~;c; mnture trees arc difficult to >50% of trees have > 25-50% of trees have <25% of trees have > 
replace 
./ 14" dbh > 14'' dbh 14" dbh 
Gt·ove size 
Vitality, resilience of grove generally 
increases with size >5 acres in size ./ 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dicback or Extensive dieback or 
~cncral condition and signs of threats, low potential threats; high disturbance; or 
~icbaek, threats, disturbance disturbance ./ invasive species invasives dominate 
Visibility Visible from arterial Visible from local 
Groves clearly visible from public street or public street or private Not visible from 
lands h~,·c greater value park/open space ./ common open space street or open space 
Screening/Buffering Between industrial or 
Groves may scn·c as land usc commercial uses and Between similar land 
buffers; depending on density, residential or open uses, or similar land No (or very limited) 
loc~t ion, uses space uses ./ use characteristics buffer function 
Accessibility Some physical or 
~rcatcr access provides more legal access limits; or 
lp[llWtunity liJr public usc; but Unrestricted public part pub! ic, part Privately owned or 
inappropriate on private lots access private land -/ inaccessible 
Rarity 
Unusual features (e.g., large grove or Uncommon features 
tree siT.C, or rare species) or Rare natural or or combination of No uncommon 
historical value cultural features features -/ features 
Educationai/Rec. Potential 
Accessible gro,·es with unusual Accessibility and Accessibility and 
ICaturcs oiler recreational and/or Rarity are high or Rarity are both Accessibility or 
··ducatinn~ l values medium medium -/ Rarity are low 
Wildlife Habitat Di verse structure, Good source of Provides few habitat 
Habitat functions for terrestrial species mix; high food, cover, territory functions, minimal 
species, connectivity, diversity connectivity; !g. size ./ for wildlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development (< ! unit per acre) ./ developed surrounded 
SUB-TOTALS 1 X5 6 X3 3 X1 
TOTALS . ·: 5 ,.• .18 3 ' . . ·~·c::; 
' 
.. 
Comments: Pileated woodpecker ho les in stumps. Evergreen/ deciduous is 80:20 here. Some ivy in trees. 
Ciry o f Tiganl Urban l'or~s try CoJc R~, · i siom I \' olume II I 358 
-~~ 
- ---- --- --
--~ 
GROVE SITE #: 47 SIZE: 2.02 acres SCORE: 24 
DATE: 9/10/2010 LOCATION: Carmen & 116th MAP: 47 
FIELD STAFF: DB GOALS SITE? Yes PHOTOS: 537 
~ GroyeDescriptlon ~· .· .. ~ .•.. · .. · .. 
:: c ....... . < . . 
Mixed forest of Oregon ash, red alder, Douglas fir, big leaf maple; Understory dominated by invasives: Himalayan blackberry, 
English ivy. Riparian corridor of tributary to Summer Creek. 
Function/ Characteristic HIGH MEDIUM LOW 
Grove matu rityffree size 
Scenic and natural values increase 
with age; mature trees nrc dillicult to >50% of trees have > 25-50% of trees have <25% of trees have > 
replace 14" dbh ./ > 14" dbh 14" dbh 
Grove size 
Vitality, resilience of grove generally 
increases with size >5 acres in size ./ 2 to 5 acres in size < 2 acres in size 
. 
Health Healthy: no visible Some dieback or Extensive dieback or · 
kncral condition and signs of threats, low potential threats; high disturbance; or 
licback, threats, disturbance disturbance invasive species ./ invasives dominate 
Visibility Visible from arterial Visible from local 
Groves clearly visible from public street or public street or private Not visible from 
lands have greater value park/open space ./ common open space street or open space 
Screening/Buffering Between industrial or 
Groves may serve as land usc commercial uses and Between similar land 
butlers; depending on density, residential or open uses, or similar land No (or very limited) 
location, uses space uses ./ use characteristics buffer function 
Accessibility Some physical or 
Greater access provides m(n'c legal access limits; or 
~ppot1unity for public usc; but U ttrestricted pub I ic part public, part Privately owned or 
inappropriate on private lots access ./ private land inaccessible 
Rarity 
Unusual features (e.g., large grove or Uncommon features 
tree size, or rare species) or Rare natura I or or combination of No uncommon 
historical value cultural features features ./ features 
EducationaVRec. Potential 
Accessible groves with unusual Accessibility and Accessibility and 
tcnturcs otTer recreat ional and/or Rarity are high or Rarity are both Accessibility or 
educational values medium medium 
./ Rarity are low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
Habitat functions for terrestrial species mix; high food, cover, territory functions, minimal 
species, connect ivity, diversity connectivity; lg. size ./ for wildlife connectivity 
Existing Development Undeveloped Part ially Developed, or 
Groves with development (< I unit per acre) ./ developed surrounded 
SUB-TOTALS 0 X5 7 X3 3 X1 
TOT~LS · .... :.:.·_.o ...... ,. ..•. 21 . . ·. 3 . . ~ .. 
. . .. ~ .· .·· .· · .. 
Comments: Dense ivy climbing t rees. Dense Himalayan blackberry. Public at northeast end, but access limited 
by steep slopes, lack of t rails . Connectivit y good to east. 
City o f Tigard Urban Forestry Code Revisions I Volume ll I 359 
GROVE SITE #: 48 SIZE: 6.99 acres SCORE: 34 
DATE: 9/10/2010 LOCATION: Fonner and 13th MAP: 48 
FIELD STAFF: DB GOAL 5 SITE? Yes PHOTOS: 538-540 
. Grov_eDescription ..... . .. ; 
.: . .. · 
Mixed forest, dom red a lder, big leaf maple, western red cedar, Understory dominated by Himalayan blackberry and English 
ivy. of tributary. Riparian corridor to Summer Creek Large pond is located near southwest end oftree grove. 
Function( Characteristic HIGH MEDIUM LOW 
Grove maturity/Tree size 
Scenic and natural values increase 
with age; mature trees arc difficult to >SO% of trees have > 25-50% of trees have <25% of trees have > 
replace 14'' dbh ,/ > 14 .. dbh 14'' dbh 
Grove size 
Vitality, resilience of grove gcncmlly 
increases with size ,/ >5 acres in size 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
General condi tion and signs or threats, low potential threa ts; high disturbance; or 
~ icback, threats, disturbance disturbance ,/ invasive species invasives dominate 
Visibility Visible from arterial Vis ible from local 
Groves clearly visible from public street or pub lic street or private Not visible from 
lands have greater value park/open space ,/ common open space street or open space 
Screening/Buffering Between industrial or 
kJroves may serve as land usc commercial uses and Between similar land 
!butlers; depending on density, residential or open uses, or similar land No (or very limited) 
location, uses space uses ,/ use characteristics buffer function 
Accessibility Some physical or 
kJ realer access provides more legal access limits; or 
!oPPOrtunity tl.>r public usc; hut Unrestricted public part pub I ic, part Privately owned or 
inappropriate on private lots access ,/ private land inaccessible 
Rarity 
Unusual features (e.g., large grove or Uncommon featu res 
tree size, or rare species) or Rare natural or or combination of No uncommon 
1istorical value cultural features ,/ features feat ures 
Educationai/Rec. Potential 
Accessible groves with unusual Accessibility and Accessibility and 
features otler recreational and/or Rarity are high or Rarity arc both Accessibility or 
cducationalvulucs medium ,/ medium Rarity are low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
Habitat 1\lnctions f<>r terrestrial species mix; high food, cover, terri tory functions, minimal 
species, connectivity, diversity ,/ connecti vity; lg. size for wildlife connectivi ty 
Existing Development Undeveloped Part ially Developed, or 
Groves with development (< I unit per acre) ,/ developed surrounded 
SUB-TOTALS 2 X 5 8 X3 0 X1 
TOTALS .·· . ' 10 ' 24 0 · · . 
' 
Comments: Good connectivity along ripari an corridor, good interspersion of habitats, understory badly 
impacted by invasives . English ivy is cl imbing trees. Pond area is publically owned, access okay. 
Po nd formed by constructed dam. 
City ofTiganJ Urban l:orcstry Code RcY isions I \ 'olumc II I 3611 
:GROVE SITE#: 49 SIZE: 1.54 acres SCORE: 18 
!DATE: 9/9/2010 LOCATION: Fonner/121 st MAP: 49 
FIELD STAFF: ACS GOAL5SITE? No PHOTOS: 5693 
Grove Des~~p!i()n ~~ --~---· ~-· . _______  .__ c .. -... . " . . ... :. :··. ~-- .::-: _ . . ·:.:: .. ·. :: .. 
... · ' -'--'-·. ;_ . ....:.. . ··· 
Mixed grove dominated by Oregon ash and black cottonwood, with a few paper birch and Douglas fir trees. The understory 
is domi nated by Himalayan blackberry and ash saplings. 
Function/ Characteristic 
Grove maturityf free size 
Scenic and natuml va lues incrc;•sc 
lwith age; mature trt'CS am dinicullto 
replace 
Grove size 
Vitality, resi lience of grove generally 
increases with size 
Health 
pencral condit ion and signs or 
~ieback, threats, disturbance 
Visibility 
!Groves clearly visib le Ji·om public 
lands have greater value 
:Screening/Buffering 
jaroves may serve as land usc 
ibuficrs; depending on density, 
location, uses 
Accessibility 
!Greater access provides more 
jopportunity tor public usc; but 
inappropriate on t>ri vale lots 
Rarity 
Unusual feat ures {e.g., large grove or 
tree size, or rare species) or 
historical value 
Educational/Rec. Potential 
Accessible groves with unusual 
features o llcr recreationa l and/or 
pducational values 
Wildlife Habitat 
Habitat timctions tor tciTcstrial 
!species, connectivity, diversity 
Existing Development 
Groves with development 
SUB-TOTALS 
TOTAL$~ / j•··-· · 
0 
0 
HIGH 
>50% of trees have > 
14., dbh 
>5 acres in size 
Healthy: no visible 
threats, low 
disturbance 
Visible from arterial 
street or public 
park/open space 
Between industrial or 
commercial uses and 
residential or open 
space uses 
Unrestricted public 
access 
Rare natural or 
cultural features 
... 
Accessibility and 
Rarity are high or 
medium 
Di verse structure, 
species mix; high 
connectivity;!& size 
Undeveloped 
(<I unit per acre) 
X5 
Comments: Could be built on; development surrounds grove. 
v' 
v' 
v' 
v' 
4 
_12 .· 
MEDIUM 
25-50% of trees have 
> 14.' dbh 
2 to 5 acres in size 
Some dieback or 
potential threats; 
invasive species 
Visible from loClll 
street or private 
common open space 
Between similar land 
uses, or similar land 
use characteristics 
Some physica l or 
legal access limits; or 
part public, part 
pri vale land 
Uncommon features 
or combination of 
features 
Accessibility and 
Rarity are both 
medium 
Good source of 
food, cover, territory 
for wildlife 
Partially 
developed 
X3 
City of Tigard Urban Fores lry Code Revisions I Volume II I 361 
v' 
v' 
.y" 
v' 
v' 
v' 
LOW 
<25% of trees have > 
14" dbh 
< 2 acres in size 
Extensive dieback or 
high disturbance; or 
invasives dominate 
Not visible from 
street or open space 
No (or very limited) 
butTer function 
Privately owned or 
inaccessible 
No uncommon 
features 
Accessibility or 
Rari ty are low 
Provides few habitat 
functions, minimal 
connectivity 
Developed, or 
surrounded 
6 IX1 
6· .. >:: I :) .· 
GROVE SITE #: 51 SIZE: 5.91 acres SCORE: 26 
DATE: 9/9/2010 LOCATION: Sevilla, south of Walnut MAP: 51 
FIELD STAFF: ACS GOAL 5SITE? Yes PHOTOS: none 
Grove Description .. .. 
·. /' > . · . 
Mixed: Douglas fi r/big leaf maple in upper areas, bottomland has Oregon ash 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturity/Tree size 
Scen ic and natural values increase 
vith age; mature t ree~ arc dilllcult to >50% of trees have > 25-50% of trees have <25% of trees have> 
replace 
../ 14" dbh > 14'' dbh 14 .. dbh i 
Grove size I Viwlity, resilience of grove generally 
incteuscs wi th size 
../ >5 acres in size 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
Jenera! condit ion and signs of threats, low potential threats; high dist urbance; or 
tieback, threats, disturbance disturbance ../ itwasive species invasives dominate 
Visibility Visible from arterial Visible from local 
1tovcs clearly visib le from publ ic street or public street or private Not visib le from 
lands have greater value park/open space common open space ../ street or open space 
Screening/Bufferi ng Between industrial or 
irovcs may serve as land usc commercial uses and Between similar land 
buftcrs; depending on density, residential or open uses, or similar land No (or very limited) 
local ion, uses space uses ../ use characteristics buffer function 
Accessibility Some physical or 
Greater access provides more legal access limits; or 
opportunity for public usc; but Unrestricted public part public, part Privately owned or 
inappropriate on private lots access lpri vate land ./ inaccessible 
Rarity 
Unusual lcaturcs (e.g., large grove or Uncommotl features 
rcc size, or rare species) or or combination of No uncommon 
!historical value features ../ features 
Educationai/Rec. Potential 
Accessible groves with unusual Accessibility and Accessibility and 
1<.-aturcs oiler recreational and/or Ra ri ty are high or Rarity are both Accessibility or 
educational values medium medium ./ Rarity arc low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
Habitat llmctions for terrestria l species mix; high food, cover, terri tory functions, minimal 
pceics, connectivity, diversity connectivity; lg. size ../ for wildlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves wi th development (< l unit per acre) ../ developed surrounded 
SUB-TOTALS 2 XS 4 X3 4 X1 
TOTALS • / . :. 10 
. • J 12 4 ~; .. ·. ' .·. : . 
Comments: Overstory viewed from local streets over houses. 
City of Tigard Urban Forestry Code Re,·isions I \'olume II I 362 
- - -
---------
- - ·----
GROVE SITE #: 51 a SIZE: 12.84 acres SCORE: 26 
DATE: 9/9/2010 LOCATION: Alberta St., west of 121 st MAP: 51 a 
FIELD STAFF: ACS GOAL 5 SITE? Yes PHOTOS: none 
~rove Description 
... 
Mixed: Douglas fir/big leaf maple in upper areas, bottomland has Oregon ash 
Function/ Characteristic HIGH MEDIUM LOW 
Gt·ove maturity!free size 
Scenic and natural value.• increase 
\'ith age: mature trees arc dillicuh to >50% of trees have > 25-50% of trees have <25% of trees have > 
replace 
./ 14" dbh > 14" dbh 14" dbh 
Grove size 
Vitality, resilience of grove generally 
increases with size 
./ >5 acres in size 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
General condition and signs of threats, low potential threats; high disturbance; or 
dicback, threats, disturbance disturbance ./ invasive species invasives dominate 
Visibility Visible from arterial Visible from local 
proves clearly visible from public street or public street or private Not visible from I lands have greater value park/open space common open space ./ street or open space 
Screening/Buffering Between industrial or 
iroves may serve as land usc commercial uses and Between similar land 
buffers: depending on density, residential or open uses, or similar land No (or very limited) 
location, uses space uses ./ use characteristics buffer function 
Accessibility Some physical or 
Greater access providt.os more legal access limits; or 
opportunity tor public usc; but Unrestricted public part public, part Privately owned or 
inappropriate on private lots access private land ./ inaccessible 
Rarity 
Unusual tbatures (e.g., large grove or Uncommon features 
tree si?.e, or rare spcci<:-'S) or Rare natural or or combination of No uncommon 
historical value cultural features features ./ features 
EducationaiJRec. Potential 
Accessible gro,·es with unusual Accessibility and Accessibility and 
features offer recreational and/or Rarity are high or Rarity are both Accessibility or 
educational values medium medium ./ Rarity are low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
Habitat funet ions for terrestrial species mix; high food, cover, territory functions, minimal 
pccics, connectivity, diversity connectivity; lg. size ./ for wildlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development (<I unit per acre) ./ developed surrounded 
SUB-TOTALS 2 xs 4 X3 4 X1 
TOTALS 10 . . . J . 12 4 
---- --
" ~-- :~~_:_~~·_:_ - -- --~__: ___ ____ :_____;___._·_: _ _._.-'.._ __ · - - _:··..:.: _. _:._: __ ____ ._:.....:....__..__:__: _ - - - ~· __----'..._......:.:_~ --
Comments: Overstory viewed from local streets over houses. 
City of Tigard Urban Forestry Code Re,·isions I Volume II I 363 
GROVE SITE #: 52 SIZE: 3.27 acres SCORE: 38 
DATE: 9/10/2010 LOCATION: Gaarde and 129th MAP: 52 
FIELD STAFF: DB GOAL SSITE? Yes PHOTOS: 550 
Grove Description 
... 
Mixed forest dom inated by: Do uglas fir , big leaf maple , red alder, western red cedar. Understory do minated by: Himalayan a few areas 
blackberry with dominated by natives (sword fern , vine maple, th imble berry, dew berry) . Riparian corridor of Kru eger Creek . 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturity/Tree size 
Scenic and natural values increase 
vith age; mature trees nrc difficult to >50% of trees have > 25-50% of trees have <25% of trees have > 
replace 14'' dbh o/ > 14" dbh 14" dbh 
Grove size 
Vitalit y, res ilience or grove generally 
inerc;~scs wi th size >5 acres in size o/ 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
iencra l condit ion and signs or threats, low potential threa ts; high disturbance; or 
tieback. threats. disturbance distu rbance o/ invasive species invasives dominate 
Visibili ty Visible from arteria l Visible from local 
lr, l'O\'Cs clearly visible from public street or public street or pri vale Not visible from 
lands hnvc greater vnluc park/open space o/ common open space street or open space 
Screening/Buffering Between industrial or 
irovcs may serve as land usc commercia l uses and Between similar land 
buffers; depending on density, residential or open uses, or similar land No (or very limited) 
location, usL-s space uses ./ use characteristics buffer function 
Accessibility Some physical or 
ircatcr access provides more legal access limits; or 
ppportun ily lor public usc; bu t Unrestricted pub I ic part pub lie, part Privately owned or 
illappropriatc on private lots o/ access private land inaccessible 
Rarity 
Unusual fea tures (e.g., large grove or Uncommon features 
tree size, or rare species) or Rare natural or or combination of No uncommon 
historical value cultural features ./ features features 
Educational/Rec. Potential 
Access ible groves "·ith unusual Accessibility and Accessibili ty and 
lcnturcs ollcr recreational and/or Rarity are high or Rarity are both Accessibil ity or 
educational values o/ medium medium Rarity are low 
Wildlife Habita t Diverse structure, Good source of Provides few habitat 
Habitat fun ct ions for terrestrial species mi x; hi gh food, cover, territory functions, minimal 
species, connectivity, diversity o/ connectivity; (g. si;z;e for wildlife connectivity 
Exis ting Develop ment Undeveloped Partially Developed, or 
Groves wi th development o/ (<I unit per acre) developed surrounded 
SUB-TOTALS 4 X5 6 X 3 0 X 1 
TOTALS 
,,. 
20 
-· 
18 _Q 
•. 
Comments: Good connectivity (somewhat limited by streets); Perennial st ream. Appears to be put open 
space with a t ra il runn ing the length of the tree grove (f rom Gueefield to Gaarde Streets ). Scattered snags. 
City of Tigard Urban Forestry Colle Rc,·isions I \'olumc II I 3(,4 
GROVE SITE #: 54 SIZE: 3.88 acres SCORE: 20 
DATE: 9/9/2010 LOCATION: 1-5/Hwy 217 interchange MAP: 54 
FIELD STAFF: DB GOAL 5SITE? Yes PHOTOS: 526 
Grove Description ... •. . ' .····· < 
Deciduous forest dominated by bigleaf maple with scattered large Douglas fir . A small patch of Oregon oak is located at the 
northwest end. A small creek runs through the grove. Understory is dominated by English ivy, Himalayan blackberry, and 
other invasive species. 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturity/Tree size 
Scenic and natural values increase 
,·ith age; mature trees arc di flicult to >50% of trees have > 25-50% of trees have <25% of trees have > 
replace 14'' dbh -/ > 14'' dbh 14" dbh 
Grove size 
Vitality, rcsilinncc ol' grove generally 
incrt:ascs with size >5 acres in size -/ 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
General condition and signs of threats, low potential threats; high disturbance; or 
dicback, threats, disturbance disturbance -/ invasive species invasives dominate 
Visibility Visible from arterial Visible from local 
~roves clearly visible fl·om pub tic street or public street or private Not visible from 
lands have greater value 
-/ park/open space common open space street or open space 
Screening/Buffering Between industrial or 
~roves may serve as land use comercial uses and Between similar land 
butlers; depending on density, residential or open uses, or simi! ar land No (or very limited) i 
location, uses space uses use characteristics ./ buffer function 
Accessibility Some physical or 
,rcatcr access provides more legal access I imits; or 
opportunity for public usc; but Unrestricted public part public, part Privately owned or 
inappropriate on private lots access private land -/ inaccessible 
Rarity 
Unusual features (e.g., large grove or Uncommon features 
rce size, or rare species) or Rare natural or or combination of No uncommon 
historical value cultural features features -/ features 
Educationai/Rec. Potential 
Accessible groves with unusual Accessibility and Accessibility and 
fl~aturcs oller recreational and/or Rarity are high or Rarity are both Accessibility or 
cducat ional values medium medium 
-/ Rarity are low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
Habitat functions for terrestrial species mi x; high food, cover, territory functions, minimal 
species, connectivity, diversity connectivity; lg. size for wildlife 
-/ connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development (<I unit per acre) developed -/ surrounded 
SUB~ TOTALS 1 X5 3 X3 6 X1 
TOTALS . . . .'. ·:., ... 5 
.· .. ~ .··' .. 9 ;6 .· , : ' L .. , · ·~ .: .· . .. . 
Comments: Broadly linear, surrounded with parking lots. Poor <;onnectivity. 
City of T igard Urban Forestry Code Re,·isions I Volume II I 365 
GROVE SITE #: 55 SIZE: 15.71 acres SCORE: 40 
DATE: 9/9/2010 LOCATION: BPA easemenUNahcotta Dr. MAP: 55 
FIELD STAFF: AS GOAL 5 SITE? Yes PHOTOS: 5680-1 
Grove Description 
Evergreen forest dominated by Douglas fir . Other species present inc lude red alder, bigleaf maple, and beaked hazelnut . 
Understory difficult to see due to impenetrable shrubs/blackberry. 
Function( Characteristic HIGH MEDIUM LOW 
Grove maturity/Tree size I Scenic and natural values increase 
with age; mature tr~>cs are dillicult to >50% of trees ha ve> 25-50% of trees have <25% of trees have > 
replace ,/ 14" dbh > 14'' dbh 14'' dbh 
Grove size 
Vitality, rcsiliancc or grove generally 
increases with size ,/ >5 acres in size 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
lcncrol condition and signs or threats, low potential threats; high disturbance; or 
lieback, threats, disturbance ,/ disturbance invasive species invasives dominate 
Visibility Visible from arterial Visible from local 
Groves clearly visible fi·om public street or public street or private Not visible from 
lands have greater va lue park/open space ,/ common open space street or open space 
Screening/Buffering Between industrial or 
Groves may serve as land usc comercial uses and Between similar land 
buncrs; depending on density, residential or open uses, or similar land No (or very limited) 
location, usL-s space uses ,/ use characteristics buffer function 
Accessibility Some physical or 
ircater access provides more legal access limits; or 
lpportunity for public usc; but Unrestricted public part pub I ic, part Privately owned or 
inappropriate on private lots access ,/ !private land inaccessible 
Rarity 
Unusual features (e.g., large grove or Uncommon features 
tree size, 01' rare specie..'} or Rare natural or or combination of No uncommon 
historical value cultural features ,/ features features 
Educationai/Rec. Potential 
Accessible grm·es with unusual Accessibility and Accessibility and 
flo:atures otTer recreational and/or Rarity are high or Rarity are both Accessibility or 
educational values medium ,/ medium Rarity are low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
Habitat limctions for tcrTcstrial species mix; high food, cover, territoty functions, minimal 
spcci~-s. connectivity, diversity ,/ connectivity; !g. size for wildlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development ,/ (< I unit per acre) developed surrounded 
SUB-TOTALS 5 X5 5 X3 0 X1 
TOTALS 25 
: 
1 5 . 0 •' ~ . 
Co mm e nts : Forest runs parallel to the BPA easement; easement is mainta ined to control vegetation height. Though 
public land, the forest Is difficult to access due to dense shrubs and Himalayan blackberry in the BPA easement. 
City of T igard Urban Forc,try Code RcYi,ions I \ 'olumc II I .366 
--- ----
GROVE SITE#: 56 SIZE: 6.69 acres SCORE: 42 
DATE: 9/10/2010 LOCATION: N of Eden & Genesis MAP: 56 
FIELD STAFF: DB GOAL 5 SITE? Yes PHOTOS: 541-542 
• (;r()V~De~cription -
. ·-
. . 
. :. . ·_ :- :_· . 
, _ _ 
' 
_., ··' ... 
Deciduous forest dominated by red alder, with patches of wester red cedar. Understory dominated by natives. Well developed 
shrub layer of red-twig dogwood, salmonberry. Some vine maple, red elderberry. Riparian corridor of Deny Dell Creek. 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturity/Tree size 
Scenic and natural values increase 
with age; mature tn.'Cs urc ditlicull to >50% of trees have > 25-50% of trees have <25% of trees have > 
replace 14" dbh -/ > 14" dbh 14" dbh 
Grove size 
Vitality, resilience of grove generally 
increases with size 
-/ >5 acres in size 2 to 5 acres in size < 2 acres in size I I 
Health Healthy: no visible Some dieback or Extensive dieback or 
pcncrul conditi(>n and signs or threats, low potential threats; high disturbance; or 
~icback, threats. disturbance 
-/ disturbance invasive species invasives dominate 
• 
Visibility Visible from arterial Visible from local 
I roves clearly visible fi·om public street or public street or private Not visible from 
lands have greater value park/open space -/ common open space street or open space 
Screening/Bufferi ng Between industrial or 
Groves may scn•c as land liSe commercial uses and Between similar land 
buOcrs; depending on density, residential or open uses, or similar land No (or very limited) 
location, uses space uses -/ use characteristics buffer function 
Accessibility Some physical or 
Greater access provides more legal access limits; or 
)pportunity for public usc; but Unrestricted public part pub lie, part Privately owned or 
inappropriate on private lots 
-/ access private land inaccessible 
Rarity 
Unusual features (e.g., large grove Ol' Uncommon features 
tree size, or rare species} or Rare natural or or combination of No uncommon 
historical value 
-/ cultural features features features 
Educationai/Rec. Potential 
Access ible groves with unusual Accessibility and Accessibility and 
features ot1cr recreational and/or Rarity arc high or Rarity are both Accessibility or 
p!ucational va lues 
-/ medium medium Rarity are low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
Habitat functions lor terrestrial species mix; high food, cover, territory functions, minimal 
·pccics, connectivity, diversity -/ connectivity; lg. size for wildlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development (<I unitperacre) -/ developed surrounded 
SUB-TOTALS 6 X5 4 X3 0 X1 
TOTAlS;' :;_•· . · · . _30 .. ~2 . 0. .. .·, . .. 
,. •'' 
.. . 
•''. 
. . 
Comments: Good connectivity upstream; Perennial st ream; Scattered large snags; Public ownership of stream 
corridor wit h excellent access - paved path. Portion sout h of Eden Court rated seperately as Site 56a. 
City of Tigard Urban Forestry Code Revisions I Volume II I 367 
GROVE SITE#: 56 a SIZE: 2.83 acres SCORE: 36 i 
DATE: 9/10/2010 LOCATION: S o/ Eden & Genesis MAP: 56 a I 
FIELD STAFF: DB GOAL 5 SITE? Yes PHOTOS: 547 i 
Grove Description 
.. · 
·. :I 
.. · .. 
Deciduous forest dominated by red alder, Oregon ash, scattered large black cottonwood and young Douglas fir and western 
rcdcedar. Understory mostly dominated by natives: red-twig dogwood, red elderberry, salmonberry, skunk cabbage, giant 
horsetail. 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturity/Tree si1.c 
Scenic and natural ,.,,lues increase 
with age; mature trees arc dirticult to >50% of trees have > 25-50% of trees have <25% of trees have > 
replace 14" dbh > 14' ' dbh ../ 14" dbh 
Grove size 
Vitality, resilience or grove generally 
increases with size >5 acres in size ../ 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieb~ck or 
Jenera I condition and sign~ of threats, low potential threats; high disturbance; or 
~icback, threats, disturbance 
../ disturbance invasive species invasives dominate 
Visibility Visible from arterial Visible from local 
Groves clearly Yisiblc lrom public street or public street or private Not visible from 
lands have greater value park/open sp~ce ../ common open space street or open space 
Screening/Buffering Between industrial or 
jGrovcs may serve as land usc commercial uses and Between similar land 
bullcrs; depending on density, residential or open uses, or similar land No (or very limited) 
location, uses space uses ../ use characteristics buffer function 
Accessibility Some physical or 
Greater access provide.' more legal access limits; or 
lopp011unity for public usc; hut Unrestricted public part public, part Privately owned or 
inappropriate on private Jots 
../ access private land inaccessible 
Rarity 
Unusualleaturcs (e.g., large grove or Uncommon features 
tree size, or rare species) or Rare natural or or combination of No uncommon 
historical value cultural features ../ features features 
Educational!Rec. Potential 
Accessible gro,·cs with \musual Accessibility and Accessibility and 
features oncr recreational and/or Rarity are high or Rarity ~re both Accessibility or 
educational values 
../ medium medium Rarity are low 
Wildlife Habitat Di verse st ructure, Good source of Provides few habitat 
Habitat Junct ions for terrestrial species mix; high food , cover, terri tory functions, minimal 
species, connectivity, diversity ../ connectivity; lg. size for wildlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development (< I unit per acre) ../ developed surrou nded 
SUB-TOTALS 4 X5 5 X3 1 X 1 
TOTALS 
• .... 
20 15 1 .-·: 
Comments: Mostly native; good connectivity; public with a paved path. 
Ci1y of Tigard Urban I 'orcs try Code RcYisions I \ ' olumc II I 3MI 
,IGROVE SITE#: 57 SIZE: 20.89 acres SCORE: 40 
DATE: 9/9/2010 LOCATION: Fern/Ascension MAP: 57 
FIELD STAFF: AS GOAL 5 SITE? Yes PHOTOS: 5678-9 
Grove Description .... :. ::.:··· 
Mixed forest dominated by Douglas fir, bigleaf maple, black cottonwood, red alder. Understory comprised of English ivy, 
dull Oregon grape, sword fern, thimbleberry, and big!eaf maple saplings. 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturity/Tree si1:e 
Scenic ami natural va lues increase 
,·ith age; mature trees nrc dilficult to >50% of trees have > 25-50% of trees have <25% of trees have > 
replace y" 14" dbh > 14'' dbh 14" dbh 
Grove size 
Vitality, rcsiliance ol' grove genera lly 
increases with si1.c y" >5 acres in size 2 to 5 aeres in size < 2 acres in size 
Health Healthy: no visible Some dicback or Extensive dieback or 
General condition and signs of threats, low potential threats; high disturbance; or 
tieback, threats, disturbance disturbance y" invasive species invasivcs dominate 
Visibility Visible from arterial Visible from local 
proves ck·arly visib le from public street or public street or private Not visible from 
lands have greater value y" park/open space common open space st reet or open space 
Screening/Buffering Between industrial or 
I roves may sen·c as land usc comercial uses and Between similar land 
[butTers; depending on density, residential or open uses, or similar land No (or very limi ted) 
location, uses space uses y" use characteristics buffer function 
Accessibility Some physical or 
Greater access provides more legal access limits; or 
opportunity for public usc; but Unrestricted public part public, part Priva tely owned or 
inappropriate on private lots access y" private land inaccessible 
Rarity 
Unusual leaturcs (e.g., large grove or Uncommon features 
tree size, or rare species) or Rare natural or or combination of No uncommon 
historical va lue cultural features y" features features 
EducationaVRec. Potential 
• 
i\cccssiblc groves with unusual Accessibility and Accessibility and 
features oncr rccr~~dtional and/or Rarity are high or Rarity are both Accessibility or 
ducationalvalucs medium y" medium Rarity are low 
Wildlife Habitat Diverse structure, Good source of Provides fev,o habitat 
Habitat !unctions fl\r terrestrial species mix; high food, cover, territory functions, minimal 
species, connectivi ty, diversity y" connectivity; lg. size for wildlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development ./ (<I unit per acre) developed surrounded 
SUB-TOTALS 5 X5 5 X3 0 X1 
TOTALS .. 25 15 0 ,. 
Comments: North end developed (low density residential), south end in public ownership. Developed at edges. 
Small drainage runs through center of grove. 
Cit}' of Tigard Urban lo'orc,try Code Re,·isions I Volume II I 369 
GROVE SITE #: 59 SIZE: 13.18 acres SCORE: 30 
DATE: 9/9/2010 LOCATION: Maplecrest MAP: 59 
FIELD STAFF: AS GOAL 5 SITE? Yes PHOTOS: 5684 
.· Grove Description · .. ·,... ;·: .' 
Mixed forest dominated by Douglas tir, bigleaf maple. The understory consists of beaked hazelnut, maple sapli ngs, lady 
fern. and swordfern . 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturity/Tree size 
Scenic and natural va lues increase 
with age; mature trees arc di11icult to >50% of trees have > 25-50% of trees have <25% of trees have > 
replace 14'' dbh ./ > 14" dbh 14'' dbh 
Grove size 
Vitality, rcsiliancc of grove gencrall) 
increases with site 
./ 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
pcneral condition and signs of threats, low potential threats; high disturbance; or 
tieback, threats, disturbance 
./ disturbance invasive species invasives dominate 
Visibility Visible from arterial Visible from local 
Groves clearly visible trom public street or public street or private Not visible from 
lands have greater value park/open space ./ common open space street or open space 
Screening/Buffering Between industrial or 
Groves may serve as land usc comercial uses and Between similar land 
bu!l'crs; depending on density, residential or open uses, or similar land No (or very limited) 
location, uses space uses ./ use characteristics buffer function 
Acccssibili ty Some physical or 
~lrcatcr access provides more legal access limits; or 
f:>pportunity tor public usc; but Unrestricted public part public, part Privately owned or 
inappropriate on pri vale lots access private land ./ inaccessible 
Rarity 
Unusual features (e.g., large grove or 00 Uncommon features 
rce size, or rare species) or Rare natural or or combination of No uncommon 
historical value cultural features features ./ features 
Educational/Rec. Potential 
Accessible groves with unusual Accessibility and Accessibility and 
features o11cr recreational and/or Rarity are high or Rarity are both Accessibility or 
educational values medium medium 
./ Rarity are low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
Habitat functions lor tcrr~-s trial species mix; high food, cover, territory functions, minimal 
species, connectivity, diversity connectivity; lg. size 
./ for wildlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development ./ (< 1 unit per acre) developed surrounded 
SUB-TOTALS 3 X5 4 X3 3 X1 
TOTALS > • .•. ·.·.·.~ .> .· 15 
• c· : .:.~ .. 12 .· 3 
·'· 
Comments: Forested tract is in private ownership. Undeveloped but there are several stu bouts leading to the grove. 
Small drainage runs through center of grove. 
City of T igard Urban l'orcstry Code Re,·isions I \'olumc II I 37ll 
GROVE SITE#: 60 SIZE: 5.25 acres SCORE: 40 
DATE: 9/10/2010 LOCATION: S o/115th & Terrace Trails MAP: 60 
FIELD STAFF: DB GOAL 5 SITE? Yes PHOTOS: 546 
.·. Grove Description ·.·.•·· .. : / ·.·' ·. ;.· 
. 
•• 
Deciduous forest dominated by red alder, big leaf maple, scattered Douglas tir. Understory mostly dominated by natives : 
Red-twig dogwood, hazelnut, vine maple, giant horsetail. Some Himalayan blackberry thickets and scattered English ivy. I 
Riparian corridor of tributary to Derry Dell Creek. i i 
! 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturity/Tree size . 
Scenic and natural value.~ increase 
with age; mature trees arc dit1icult to >50% of trees have > 25-50% of trees have <25% of trees have> 
replace 14"dbh > 14' ' dbh .,/ 14" dbh 
Grove size 
Vitality, resilience of grove generally 
increases with size .,/ >5 acres in size 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
~encrul condition and signs of threats, low potential threats; high disturbance; or 
lichack, threats, disturbance .,/ disturbance invasive species invasives dominate 
Visibility Visible from arterial Visible from local 
I<Jroves clearly visible from public street or public street or private Not visible from 
lands have greater value park/open space ../ common open space street or open space 
Screening/Buffering Between industrial or 
Groves may serve as land usc commercial uses and Between similar land 
butTers; depending on density, residential or open uses, or similar land No (or very limited) 
location, uses space uses .,/ use characteristics buffer function 
Accessibility Some physical or 
Greater access provides more legal access limits; or 
opportunity for public usc; but Unrestricted public part public, part Privately owned or 
inappropriate on private lots 
../ access private land inaccessible 
Rarity 
Unusual features (e.g., large grove or Uncommon features 
rec size, or rare species) or Rare natural or or combination of No uncommon 
1istorical value cultural features .,/ features features 
Educationai/Rec. Potential 
Accessible groves with unusual Accessibility and Accessibility and 
features oncr recreational an<lfor Rarity are high or Rarity are both Accessibility or 
f:clucational values .,/ medium medium Rarity are low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
Habitat functions fbr terrestrial species mix; high food, cover, territory functions, minimal 
~pccics, connectivity, diversity .,/ connectivity; lg. size for wildlife connectivity 
Existing Development U ndeve!oped Partially Developed, or 
Groves with development ./ (<I unit per acre) developed surrounded 
SUB-TOTALS 6 X5 3 X3 1 X1 
T():rALS· .•... ·.· ..•... 30 . ..... 9 ' _1 
Comments: Understory probably recently cleared of invasives, good connectivity, perren ial st ream. Scattered 
snags, public ownershp. General t rail throughout - good access, limit mapping to st ream corridor. 
City of Tigard Urban Forestry Code RcYisions I Volume 11 I 371 
GROVE SITE #: 62 SIZE: 25.28 acres SCORE: 32 
DATE: 9/9/2010 LOCATION: Wall St. between 217, 1-5 MAP: 62 
FIELD STAFF: DB GOAL 5 SITE? Yes PHOTOS: 527 
Grove Description 
... 
Deciduous forest with scattered large Douglas fir, bl ack cottonwood. Understory dominated by Himalayan blackberry. A few 
scattered Oregon oak. 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturity/Tree size 
Scenic and natural \"a lues increase 
with age; mature trees arc ditlkult to >50% of trees have> 25-50% of trees have <25% of trees have > 
replace 14'' dbh ./ > 14" dbh 14" dbh 
Grove size 
Vitality, resiliancc of'l!r<wc generally 
increases wlth size ./ >5 acres in size 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
General condition and signs of' threats, low potential threats; high disturbance; or 
licback, threats, disturbance disturbance ./ invasive species invasives dominate 
Visibility Visible from arterial Visible from local 
r;rovcs clearly visible rmm public street or public street or priva te Not visible from 
lan<1s have ~;realer value 
./ park/open space common open space st reet or open space 
Screening/Buffering Between industrial or 
irovcs may serve as land usc cornercial uses and Between si milar land 
bull'crs; depend in!; on density, residential or open uses, or similar land No (or very limited) 
location, uses ./ space uses use characteristics buffer function 
Accessibility Some physical or 
Greater access provides more legal access limits; or 
!oPPOrtunity lor public usc; but Unrestricted public part public, part Privately owned or 
inappropriate on private lots access pri vate land ./ inaccessible 
Rarity 
Unusual features (e.g., large grove nr Uncommon fe<1tures 
1 rce size. or rare species) or Rare natural or or combim1tion of No uncommon 
historical value cultural features features ./ features 
Educational/Rcc. Potential 
Accessible groves with unusual Accessibility and Accessibility and 
features oiler recreational and/or Rarity are high or Rarity arc both Accessibility or 
cclucationalvalucs medium medium 
./ Rarity are low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
llabitat functions for terrestrial species mix; high food, cover, territory functions, minimal 
species, connectivity, diversity connectivity; lg. size 
./ for wildlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development ./ (<I unit per acre) developed surrounded 
SUBMTOTALS 4 X5 3 X3 3 X1 
TOTALS 
. . 20 I 9 3 ·; . 
Comments: Buffers residential area from Highway 217. Isolated by highway and development. 
Cit)' of Tigard Urban l!orcstry Code Rc,·isions I \ 'olumc II I 372 
GROVE SITE #: 63 SIZE: 1.48 acres SCORE: 22 
DATE: 9/10/2010 LOCATION: N of Gaarde & 110th MAP: 63 i I 
FIELD STAFF: DB GOAL 5 SITE? Yes PHOTOS: 549 
Grove Description 
. . 
.. 
Mixed woodland of large Douglas fir and red alder. Underst01y quite open . Underst01y dominated by a mix of native (giant i 
horsetail, Suksdorfs hawthorn, California dewberry, and lady fern) and introduced invasiveslornamental species I 
{Himalayan blackberry, Engl ish ivy, red canarygrass, English hawthom) 
I 
I 
Function/ Characteristic HIGH MEDIUM LOW 
Grove matul'i ty/Tree size 
Scenic and natural values increase 
with age; mature tr~'CS nrc diflicult to >50% of trees have > 25-50% of trees have <25% of trees have> : 
replace 14" dbh .( > 14" dbh 14'' dbh . 
Grove size 
Vitality, resilience of grove generally 
incrcas~:S with size > 5 acres in size 2 to 5 acres in size .( < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
r,cncrul condition and signs or threats, low potential threats; high disturbance; or 
tieback, threats, disturbance disturbance .( invasive species invasivcs dominate 
Visibili ty Visible from arterial Visible from local 
k-Jrovcs c lc~rly visible 11'\lll'l public street or pub! ic street or private Not visible from 
lands have grcalcr value park/open space ./ common open space street or open space 
Screening/Buffering Between industrial or 
}roves may serve as land use commercial uses and Between similar land 
lbuflers; depending on density, residential or open uses, or similar land No (or very limited) 
location, uses space uses .( use characteristics buffer function 
Accessibility Some physical or 
Grcalcr access provides more legal access limits; or 
opportunity fbr public usc; but Unrestricted public part publ ic, part Privately owned or 
inappropriate on private lots access private land inaccessible 
Rarity 
Unusual features (e.g., large grove or Uncommon features 
tree si7.e, or rare species) or Rare natural or or combination of No uncommon 
1istorical va lue cultural features .( features features 
Educationai/Rec. Potential 
Accessible groves with unusual Accessibility and Accessibili ty and 
features offer recreational and/or Rarity are high or Rari ty are both Accessibi lity or 
cducat ional values medium medium Rarity are low 
• Wildlife Habitat Di verse structure, Good source of Provides few habitat 
Habitat functions for terrestrial species mix; high food, cover, territory functions, minimal 
species, connectivity, diversity connectivity; lg. size .( for wildlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development (<1 unit per acre) ./ developed surrounded 
SUB· TOTALS 0 X5 7 X3 1 X1 
TOTALS ' ·· 0 , . ... •. 21 . 1 
·- ·· 
,. 
Comments : Private, no access . Perennial creek. Good connectivity; Portions to west should be excluded-
developed/fragmented. 
City of Tigard Urban Forestry Code Re,-isions I Volume II I 373 
GROVE SITE #: 64 SIZE: 5.31 acres SCORE: 24 I 
DATE: 9/13/2010 LOCATION: McDonald Avenue MAP: 64 I 
FIELD STAFF: AS GOAL 5 SITE? Yes PHOTOS: 5711 
.·. Grove Description •' -1 
Mixed forest in riparian zone of small creek. Red alder, western redcedar codominate, with scattered Douglas fir , bigleaf maple I 
and Oregon ash. Engl ish ivy, Himlayan blackberry dominate the upland understory, with reed canarygrass dominating the 
channel and wet margin. Some understory near residences is omamentaL 
Function/ Characteristic HIGH MEDIUM LOW 
Grove m atu r ityffrec size 
Scenic ond natural ,·a lues increase 
with a~c: mature trees arc dillicult to >50% of trees have > 25-50% of trees have <25% of trees lwve > 
replace 14'' dbh > 14" dbh ./ 14" dbh 
Grove size 
Vitality, rcsiliuncc of !;ro,·c generally 
increases ,,·ith size 
./ >5 acres in size 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dicback or Extensive dieback or 
lrJcncral condition and signs of threats, low potential threats; high dis tu rbance; or 
tieback, th reats, disturbance disturbance ./ invasive species invasives dominate 
Visibility Visible from arterial Visible from local 
Groves clearly visible ti·om public street or public street or pri vate Not visible from 
lands ha\'c greater va lue park/open space ./ common open space street or open space 
Screening/Buffer ing Between industrial or 
)roves •nay serve as land usc comercial uses and Between similar land 
bul1crs; depending on density, residential or open uses, or similar land No (or very limited} 
toea I ion, uses space uses .(' usc characteristics buffer function 
Accessibility Some physical or 
lrJrcatcr access provides more legal access limits; or 
lpportun ily for public use; but Unrestricted public part public, part Privately owned or 
inappropriate on private lots access private land ./ inaccessible 
Rarity 
Unusual features (e.g., large grove or Uncommon features 
tree size, or rare species) or Rare natural or or combination or No uncommon 
1istorical va lue cultural features features ./ features 
EducationalfRec. Potential 
Accessible gro,·cs wi th umtstml Accessibility and Accessibility and 
features oiler recreational and/or Rarity arc high or Rarity arc both Accessibility or 
•ducational valuL-s medium medium 
./ Rarity arc low 
Wild life Habitat Diverse structure, Good source or Provides few habitat 
I !abita! llmctions lor tcn·cstrial species mix; high food, cover, territory functions, minimal 
peeics, connectivity, diversit>' connectivity; lg. size 
./ for wildlife connecti vity 
Existing Development Undeveloped Partially Developed, or 
Groves with development (<I unit per acre) ./ developed SUil'OUnded 
SUB-TOTALS 1 X5 5 X3 4 X1 
TOTALS · ... ·•· _ .·. s 15 4 
Comments: Drainage and vegetated corridor. Tree canopy extends into large-lot residential yards, 
Himalayan blackberry is heavy in the upland understory; some clematis also present. 
City of Tigard Urban l;orcstry Code Rc,·isions I \'olumc II I 374 
GROVE SITE#: 65 SIZE: 13.02 acres SCORE: 44 
DATE: 9/10/2010 LOCATION: SW of Greenfield & Morning MAP: 65 
FIELD STAFF: DB GOAL 5 SITE? Yes PHOTOS: 543,544 
. ~rove Des~ription . · ... . .. ··· .. ·· 
.-·· .... : 
Mixed forest dominated by red alder, big leaf maple, scattered Douglas fir. Understory mostly dominated by Himalayan 
blackberry but with some native-dominated areas (swordfem, dull Oregon grape, vine maple, hazelnut, etc.). 
fncl udes riparian corridor of Krueger Creek. 
Function/ Characteristic I I HIGH I MEDIUM I I LOW 
Grove maturity/Tree size 
~ccnic and natural values increase 
with age; mature trees arc ditlicult l\l >50% of trees have > 25-50% of trees have <25% of trees have > 
replace 
./ 14'' dbh ?: 14' ' dbh 14" dbh 
Grove size 
Vitality, resilience or grove generally 
incrcast.-s with size 
./ >5 acres in size 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some die back or Extensive dieback or 
General condition and signs or threats, low potential threats; high disturbance; or 
dicback, threats, disturbance disturbance ./ invasive species invasives dominate 
Visibility Visible from arterial Visible from local 
:orovcs clearly vis ible n·om public street or public street or private 
I 
INot visible fro m 
lands have greater va lue 
./ park/open space common open space street or open space 
Screening/Buffering Between industria l or 
~roves may serve as land usc commercial uses and Between similar land 
uOers; depending on density, residential or open uses, or similar land 
I 
INo (or very limited) 
location, uses space uses ./ use characteristics butTer function 
Accessibility Some physical or 
prcatcr access provides more legal access limits; or 
lpportunity tbr public use; but Unrestricted public part public, part I r rivately owned or inappropriate on pri,,atc lots ./ access private land inaccessible 
Rarity 
Unusual features (e.g., large grove or Uncommon features 
ree size, or rare species) or Rare natural or or combination of 
I 
INo uncommon 
hist01ical va lue cultural features ./ features features 
Educationai!Rec. Potential 
'J\cccssibtc groves with unusual Accessibility and Accessibility and 
features offer recreational and/or Rarity are high or Rarity are both Accessibility or 
:ducational values 
../' medium medium Rarity are low 
~~~ildlife Habitat Diverse structure, Good source of Provides few habitat 
·labitat !unctions tbr terrestrial species mix; high food, cover, territory functions , minimal 
!species, conncctil•ity, diversity ./ connectivity; lg. size for wildlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development ./ (< I unit per acre) developed surrounded 
SUB-TOTALS 7 X5 3 X3 0 X1 
TOTALS <> ' 35 , ... 9 o .. · I .· , ~ · .. 
Comments : Good connectivity and interspersion. Riparia n corridor with perennial creek. 
Partial public ownership, good access with sewer ROW/unpaved trail 
City of Tigard Urban Forestry Code ReYisions I Volume II I 375 
GROVE SITE #: 67 SIZE: 54.40 acres SCORE: 42 
DATE: 9/9/2010 LOCATION: Men lor MAP: 67 
FIELD STAFF: AS GOALS SITE? Yes PHOTOS: 5682-3 
Grove Description . , .... 
Mixed forest. Dominant trees include Douglas fir and bigleaf maple, with beaked hazeln ut, vine maple, Oregon grape, 
oceanspray, and sword fern in the understory. 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturity/Tree si:~.e 
Scenic and natural va lues incrc:1s~ 
with age; mature trees arc dilliculllo >50% of trees have > 25-50% of trees have <25% of trees have > 
replace 
./ 14'' dbh > 14'' dbh 14" dbh 
Grove size 
Vitality, rcsiliancc of gmvc gcncm lly 
increases with si~e 
./ >5 acres in size 2 to 5 acres in size < 2 acres in si7.e 
Health Healthy: no visible Some dieback or Extensi vc dicback or 
icncral wndition and signs of threats, low potential threats; high disturbance; or 
tieback, threats, disturbance 
./ disturbance invasive species invasives dominate 
Visibility Visible from arterial Visible from local 
Groves clearly visible n·om public street or public street or private Not visible from 
lands have greater va lue park/open space ./ common open space street or open space 
Screening/Buffering Between industrial or 
iroves may scn·e as land use comercial uses and Between similar land 
lJulfers; depending on density, residential or open uses, or simi la r land No (or very limi ted) 
location, uses space uses ./ use characteristics buffer function 
Accessibility Some physical or 
prcatcr access provides more legal access limits; or 
!oJ>POrtunity for publ ic usc; but Unrest ricted public part public, part Privately owned or 
inappropriate on private lots access ./ private land inaccessible 
Rarity 
Unusual JC<lturcs (e.g., large grove or Uncommon features 
tree size, or rare species) or Rare natural or or combi nation of No uncommon 
historical value 
./ cultural features features features 
Educationai/Rec. Potential 
Accessible grm·cs wi th unusual Accessibility and Accessibility and 
features offer recreational and/or Rarity are high or Rarity are both Accessibility or 
educational va lues 
./ medium medium Rarity are low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
Habitat !'unctions for terrestrial species rnix; high food , cover, territory function s, minimal 
species, connectivity, diversity 
./ connectivity; lg. size for wildlife connectivi ty 
Existing Development Undeveloped Pat1ially Developed, or 
Groves with development (< I unit per acre) ./ developed surrounded 
SUB-TOTALS 6 X5 4 X3 0 X 1 
TOTALS 30 . 12. .o 
Comments: Mature forest with some very low-density residential tucked into the forest. Invasive cover (Himalayan 
blackberry, English ivy) moderate in places. Most of this grove is in private ownersh ip. 
City of Tigard Urban l'orcstry Code Rc,·isions I \'olumc II I .'\76 
GROVE SITE#: 68 SIZE: 2.76 acres SCORE: 20 
DATE: 9/13/2010 LOCATION: McDonald/93rd MAP: 68 
FIELD STAFF: AS GOALS SITE? Yes PHOTOS: 5712-3 
. Grove Description_ .• , .. .·. - ~ : ~ ; ·. 
Mixed forest. Bigleaf maple dominates the tree grove, with some Oregon ash, Douglas fir, and red alder. 
Small dra inage flows through grove. Understory and grove overrun by invasives: clematis, Himalayan blackberry, English 
ivy. 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturity/Tree size 
Scenic and natural va lues increase 
vith ugc; ma1Ur'C trees are ditlicult to >50% of trees have > 25-50% of trees have <25% of trees have > 
cplace ,/ 14 '' dbh > 14'' dbh 14'' dbh 
Grove size 
Vitality, resiliance of grove generally 
increases with size >5 acres in size ,/ 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
t:;cncral condition and signs of threats, low potential threats; high disturbance; or 
!ieback, threats, disturbance disturbance invasive species ,/ invasives dominate 
Visibili ty Visible from arterial Visible from local 
pro,·cs clearly visible lrom public street or public street or pri vatc Not visible from 
lands ha,·e greater value park/open space ,/ common open space street or open space 
Screening/Buffering Between industrial or 
Groves may serve as land use comercial uses and Between similar land 
I buffers; depending on density, residential or open uses, or similar land No (or very limited) 
location, uses space uses ./ use characteristics buffer function ! 
Accessibility Some physical or 
. 
[Urcater acccs.~ provides more legal access limits; or 
ppportunity lor public usc; but Unrestricted public part pub I ic, part Privately owned or 
inappropriate on private lots access private land ,/ inaccessible 
Rarity 
Unusual features (e.g., large grove or Uncommon features 
ree size, or rare species) or Rare natural or or combination or No uncommon 
historical value cultural features features ,/ features 
Educationai/Rec. Potential 
Accessible groves with unusual Accessibility and Accessibility and 
features oiler recreational andfor Rarity are high or Rarity arc both Accessibility or 
educational values medium medium ./ Rarity arc low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
Habitat functions for terrestrial species mix; high food, cover, territory functions, minimal I I 
pccies, connectivity, diversity connectivity; lg. size for wildlife ,/ connectivity I I 
Existing Development Undeveloped Partially Developed, or 
i 
Groves with development (< I unit per acre) developed ./ surrounded 
SUB-TOTALS 1 X5 3 X3 6 X1 
TOTALS ·::. __ : __ _:_:·· . . · 5 .9 .. 6_· :- ... 
... .. ., 
Comments: Very heavy cover of invasives; ivy and clematis have climbed to the tops of mature trees. 
City of Tigard Urban Forestry Code Rc,·isions I Volume II I 377 
GROVE SITE#: 69 SIZE: 2.25 acres SCORE: 24 
DATE: 9/13/2010 LOCATION: McDonald Ave. MAP: 69 
FIELD STAFF: ACS GOAL 5 SITE? Yes PHOTOS: 5710 i 
Grove Description 
Evergreen forest: Dollglas fir, English ho lly. Forest has virtually no llnderstory, similar age class. 
Function( Characteristic HIGH MEDIUM LOW 
Grove matndtyn'ree size 
Scenic and natural va lues increase 
with <Jgc; mature trt-cs arc dillicull to >50% of trees have > 25-50% of trees have <25% of trees have > 
replace 14" dbh ./ > 14'' dbh 14'' dbh 
Grove size 
Vitality, resilience or grove generally 
increases with size >5 acres in size ./ 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
lcncral condition and signs of threats, low potential threats; high disturbance; or 
lichack, threats, disturbance 
./ disturbance invasive species invasivcs dominate 
Visibility Visible from arterial Visible from local 
K;rovcs clearly visi ble from public street or public street or private Not visible from 
lands ha vc greater va luc park/open space ./ common open space street or open space 
Screening/Buffering Between industrial or 
Groves may serve as land usc commercial uses and Between si milar l11nd 
buflcrs: depending on density, residential or open uses, or simi lar land No (or very limited) 
location, uses space uses ./ use characteristics buffer function 
Accessibility Some physical or 
ircatcr access provides more legal access limits: or 
jopportunity l(w public usc; but Unrestricted public part public, part Privately owned or 
inappropriate on private lots access private land ./ inaccessible 
Rarity 
Unusual features (e.g., large grove or Uncommon feat ures 
tree size, or rare species) or Rare natural or or combination of No uncommon 
historical va lue cultural features featu res ./ features 
Educational/Rec. Potential 
1\cccssiblc gro,·cs with unusual Accessibility and Accessibili ty and 
features otrcr recreational and/or Rari ty are high or Rarity are both Accessibility or 
ducat ional values medium medium ./ Rarity are lo w 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
Habitat timet ions for terrestrial species mix; high food, cover, territory 
./ functions, minimal 
species, connectivity, di vers ity connectivity; lg. size for wi ldlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development (< I unit per acre) ./ developed surrounded 
SUB-TOTALS 1 X5 5 X3 4 X1 
TOTALS 5 15 4 . ·' 
.- . -
Comments: Trees vary f rom 6" to ~18" in size. Pure stand of Douglas fir with virtua lly absent shrub herb layers. 
Raked debris. 
City o l Tigard Urban Forestry Code Re,·ision,; I \'olume II I .HH 
--
- --------------
GROVE SITE #: 71 SIZE: 39.20 acres SCORE: 46 ! 
DATE: 9/9/2010 LOCATION: N end of Milton MAP: 71 I 
FIELD STAFF: DB GOAL S SITE? Yes PHOTOS: 528,529 
-• Gr.oye Description .. ·:.:· ":.<~:, · 
Deciduous forest dominated by Oregon white ash, red alder. Scattered large Douglas fir, black cottonwood, bigleaf maple. 
Understory mostly dominated by exotics : Himalayan blackberry, reed canarygrass, jewelweed, English ivy, but with 
some native shrubs and herbs. i 
I 
Function/ Characteristic HIGH MEDIUM LOW ! 
Grove matu r ity/Tree size i 
Scenic anclnatuml va lues increase 
vith age; matun: trees art: dinicull to >50% of trees have > 25-50%oftrees have <25% of trees have > ' 
replace 14"' dbh .{ > 14" dbh 14"" dbh 
Grove size 
Vitali ty, resilience ol"grovc generally 
increases with size .{ >5 acres in size 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
General conditi\m and signs ol" threats, low potential threats; high disturbance; or 
dicback, th reats, disturbance disturbance .{ invasive species invasives dominate 
Visibility Visible from arterial Visible from local 
Groves clearly visible from public street or public street or private Not visible from 
lands have greater value v' park/open space common open space street or open space 
Screening/Buffering Between industrial or 
Groves may serve as land usc commercial uses and Between simi lar land 
butTers; deJlcnding on density, residential or open uses, or similar land No (or very limited) 
location, uses .{ space uses use characteristics buffer function 
Accessibility Some physical or 
~Jrcater access provid<.-s more legal access limits; or 
ppportunity for public usc; but Unrestricted public part public, part Privately owned or -
inappropriate {l ll private lots v' access private land inaccessible 
Rarity 
Unusual features {e.g., large grove or Uncommon features 
tree size, or mrc SJl~'Cics) or Rare natural or or combination of No uncommon 
historical ' 'aluc .{ cultural features features features 
Educationai/Rec. Potential 
Accessible groves with unusual Accessibility and Accessibility and 
features otTer recrcutional nndlor Rarity are high or Rarity are both Accessibility or 
educational values .{ medium medium Rarity are low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
Habitat !unctions for tcn·cstria\ species mix; high food, cover, territory functions, minimal 
pccies, connectivity, diversity v' connectivity; lg. size for wildlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development v' (< I unit per acre) developed surrounded 
SUB-TOTALS 8 X5 2 X3 0 X1 
TOTALS . ··• ···. ··· .. 40 . 6 0 ; --
Comments : Snags common; Fan no Creek tributaries run t hrough tree grove; also includes marsh and pond 
habitats. Good interspersion and connect ivity. Com plex of upland, wetland/aquatic habitats. Mostly public 
trail access from multiple points. Some large Oregon white oak on east side. 
City of Tigard Urban Forestry Code Re,·isions I Volume 11 I 379 
- - --~ - . --- ----- ---- - --- - ----- -
GROVE SITE #: 73 SIZE: 1.97 acres SCORE: 24 
DATE: 9/13/2010 LOCATION: Canterbury Heights MAP: 73 
FIELD STAFF: ACS GOAL 5SITE? No PHOTOS: 5720-1 
Grove Description ·.·,· 
Evergreen forest: Douglas fir, western redcedar, hazelnut. sword fern, weedy Forbs, grasses 
Function{ Characteristic HIGH MEDIUM LOW 
Grove maturity/Tree sir.e 
Scenic and natural values increase 
with age; mature trees arc ditlicult to >50% of trees have > 25 -50% of trees have <25% of trees have > 
replace v' 14"" dbh > 14" dbh 14" dbh 
Grove size 
Vi tal ity, resilience of grove generally 
increases with size >5 acres in size 2 to 5 acres in size v' < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dicback or 
lr.cncrnl condition and signs of threats, low potential threats; high disturbance; or 
~ieback , threats, disturhancc v' disturbance invasive species invasives dominate 
Visibility Visible from arterial Visible from local 
,roves clearly visible Ji·om puhlic street or public street or private Not visible from 
lands ha\'c greater value park/open space v' common open space st reet or open space 
Screening/Buffering Between industrial or 
I roves may serve as land usc commercial uses and Between similar land 
buffers; depending on density, residential or open uses, or similar land No {or very limited) 
location, uses v' space uses use characteristics buffer function 
Acccssibilitv Some physical or 
prcater aeccs.~ i>rovides more legal access limits; or 
opportunity tor puhlic usc; but Unrestricted public part public, part Privately owned or 
inappropriate on private lots access pri vate land v' inaccessible 
Rarity 
Unusual reatures (e.g., large grove or Uncommon features 
tree size, or rare species) or Rare natural or or combination of No uncommon 
historical value cultural features features .; features 
Educationai/Rec. Potential 
Acccssihlc gro\'CS with unusuai Accessibility and Accessibility and 
features offer recreational and/or Rarity are high or Rarity are both Accessibility or 
ducational values medium medium .; Rarity are low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
Habitat lhnctions for terrestrial species mix; high food, cover, terri tory v' functions, minimal 
species. connectivity, diversity connectivity; lg. size for wildl ife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development {< I unit per acre) developed v' surrounded 
SUB-TOTALS 3 X5 1 X3 6 X1 
TOTALS ... 15 3 
.· ' 
.. 6 
Comments: Grove at back of SE attached housing. Few invasives, minimal shrub layers. 
City of Tigard Urban l'o rcstrl' Code Rc,·isions I \ 'olumc II I 3HO 
- ------ - - ----
GROVE SITE #: 74 SIZE: 3.89 acres SCORE: 29 
DATE: 9/9/2010 LOCATION: NE of BonitafHall MAP: 74 
iFIELD STAFF: DB GOAL SSITE? Yes PHOTOS: none 
Grove Description -: -_._-_.-_.·' >' 
Mixed Douglas fir, western red cedar, red alder/big leaf maple. Conifers generally large; understory dominated by invasives: 
Himalayan blackberry, English ivy, escaped ornamentals. Riparian corridor with a tributary of Fan no Creek. 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturity/Tree size 
Scenic Md natural values increase 
with age; mature trees arc diflicult to >50% of trees have > 25-50% of trees have <25% of trees have > 
replace 14'' dbh ../ > 14''dbh 14'' dbh 
Grove size 
Vitality, resilience of grove generally 
increases with si?.C >5 acres in size ./ 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
Jenera! condition and signs of threats, low potential threats; high disturbance; or 
licback, threats, di~turbancc disturbance ../ invasive species invasives dominate 
Visibility Visible from arterial Visible from local 
Groves clearly "isiblc lrom public street or public street or private Not visible from 
lands have greater value 
./ park/open space common open space street or open space 
Screening/Buffering Between industrial or 
hrovcs may SCr\'C OS land \ISC commercial uses and Between similar land 
butlers; depending on density, residential or open uses, or similar land No (or very limited) 
location, uses space uses ./ use characteristics buffer function 
Accessibility Some physical or 
prcater access provides more legal access limits; or 
fopportunity lor public use; btl! Unrestricted public part public, part Privately owned or 
inappropriate on private klts access private land ../ inaccessible 
Rar ity 
Unusual rcatures {e.g., large grove or Uncommon features 
tree size, or rare species) or Rare natural or or combination of No uncommon 
1istorical value cultural features ./ features features 
Educationai/Rec. Potential 
\ccessihle gro\'cs with unusual Accessibility and Accessibility and 
features offer recreational and/or Rarity are high or Rarity are both Accessibility or 
educational "alucs medium medium ../ Rarity are low 
Wild life Habitat Diverse structure, Good source of Provides few habitat 
Habitat functions for terrestrial species mix; high food, cover, terri tory functions, minimal 
~pccics, connectivity, diversity connectivity; lg. size ./ for wildlife ./ connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development (<I unit per acre} ../ developed surrounded 
SUB-TOTALS 1 X5 7 X3 3 X1 
TOTALS ..• _.· 5 -- .• . 21 .. 3 . .. ' ... __ , 
Comments: Very weedy understory. Connectivity is okay, th ough somewhat fragmented by development and 
crossing st reets. Area east of 80th Place was excluded- too small and fragmented. Part is in public 
ownership. Access difficult- steep, no trails or access points to the public parcel. 
City of Tigard Urban Forestry Code Revisions I Volume II 1 381 
GROVE SITE #: 75 SIZE: 24.34 acres SCORE: 38 
DATE: 9/10/2010 LOCATION: N of Bull Mountain & 126th MAP: 75 
FIELD STAFF: DB GOAL 5 SITE? Yes PHOTOS: 545 
.. Grove Description .· .. ·: 
. ·:! ,; •' -· , ... <:.·.: .. 
Mixed forc~t domi nated by Douglas fir, big leaf maple, red a lder. Understory domi nt~ted by Himalayan blackberry but with 
some native-dom ianted areas (sword fern, vine maple, dewberry, hazelnut) . Riparian corridor for tributary of Krueger Creek. 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturi ty/Tree s ize 
Scenic and nalmnl values increase 
wilh age; maltu-c lrccs arc dill1cull lo >50% of trees have > 25-50% of trees have <25% of trees have > 
replace .( 14" dbh > 14'' dbh - 14" dbh 
Grove siJ.:e 
Vilalily, resilience or grove generally 
increases wi lh size .( >5 acres in size 2 to 5 acres in size < 2 acres in size 
Health Heal thy: no visible Some dieback or Extensive dieback or 
pcncral condilion and signs of threats, low potential threats; high disturbance; or 
~ieback, lhrcats, dis! urba ne~ disturbance ./ invasive species invasives dominate 
Vis ibility Visible from arterial Visible from local 
Groves clearly visible from public street or public street or private Not visible from 
lands have grcaler value park/open space ./ common open space street or open space 
Scr eening/Buffer ing Between industrial or 
Groves may serve as land use commercial uses and Between similar land 
buffers; depending on density. residential or open uses, or similar land No (or very limited) 
local ion. uses space uses .( use characteristics buffer function 
Accessibility Some physical or 
k-Jreatcr access provides more legal access limits; or 
ppportunily for public usc; but Unrestricted public part public, part Privately owned or 
inappropriate on privale lots access ./ private land inaccessible 
Rarity 
Unusual features (e.g., large grove or Uncommon features 
1rcc size, or rare species) or Rare natural or or combinat ion of No uncommon 
hislorical value cultural features .( feat ures fea tures 
Educationai/Rec, Poten tial 
Accessible grm·es with unusual Accessib ili ty and Accessibi lity and 
fcawrcs otTer recreational and/or Rarity are high or Rarity are both Accessibili ty or 
educational va lues medium 
./ medium Rarity are low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
Habilat f\mclions for lcrrcslrial species mix; high food, cover, tenitory functions, minimal 
species, conneclivily, diversity ./ connectivity; lg. size for wildlife connectivity 
Existing Development Undeveloped Part ially Developed, or 
Groves with development .( (< I unit per ac re) developed surrounded 
SUB-TOTALS 4 X5 6 X3 0 X 1 
TOTAlS ' ·:: . 20 .... ,: 18 0 ·: : i " :· . . -· ... 
-· 
Comments: Good connectivity. Perenn ial stream. Publ ic ownership on part; access possible but limited by 
steep slopes; understory degraded by invasives . 
City of Tigard Urban I 'orcs try Code Rc,·isions I \' olumc II I .)82 
GROVE SITE #: 77 SIZE: 2.86 acres SCORE: 28 
DATE: 9/13/2010 LOCATION: Inez St. MAP: 77 
FIELD STAFF: ACS GOAL 5 SITE? Yes PHOTOS: 5714 
.Grove Des~ription .. ~ . 
.. 
Evergreen forest: Douglas fir is sole dominant, with scattered ponderosa pine, big leaf maple, English hawthorn , bird chetTy. 
Understory is a melange of mostly Himalayan blackberry with English ivy, herb-robert, dewberry 
Function/ Characteristic HIGH MEDIUM LOW 
Grove matu rity/Tree size 
Scenic and natural valu<:s incrc:Jse 
"'ith age; mature trees are dillicult to >50% of trees have > 25-50% of trees have <25% of trees have > 
replace 
./ 14" dbh > 14" dbh 14'' dbh i 
Grove size 
Vitality, resilience of grove general!) 
increases with size >5 acres in size ./ 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
tJcncral condition and signs or threats, low potential threats; high disturbance; or 
dicback, threats, disturbance disturbance ./ invasive species invasivcs dominate 
Visibility Visible from arterial Visible from local 
Groves clearly visible from public street or pub I ic street or private Not visible from 
lands have greater value park/open space ./ common open space street or open space 
Screening/Buffering Between industrial or 
Groves may serve as land use commercial uses and Between similar land 
bu lfers; depending on density, residential or open uses, or similar land No (or very limited) 
location, uses space uses ./ use characteristics buffer function 
Accessibility Some physical or 
9rcater access provides more legal access limits; or 
ppportunity for public use; but Unrestricted public part public, part Privately owned or 
inappropriate on pri vatc lots access private land .,/ inaccessible 
Rarity 
Unusual features {e.g., large grove or Uncommon features 
tree size, or rare species) or Rare natural or or combination of No uncommon 
historical value cultural features ./ features features 
Ed ucationa i/R ec. Po ten tial 
Accessible groves with unusuul Accessibility and Accessibility and 
leatures oflcr recreational and/or Rarity are high or Rarity are both Accessibility or 
ducational values medium medium ./ Rarity are low 
W ildlife Habitat Diverse structure, Good source of Provides few habitat 
Habitat functions for tciTcstrial species mix; high food, cover, territory functions, minimal 
~pccics, connectivity, diversity connectivity; 1<>. size ./ for wildlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development (< I unit per acre) ./ developed surrounded 
SUB-TOTALS 1 XS 7 X3 2 X1 
TOT~LS /;·.·.)<··.·.•· .•..•. · . - 5 .. 21 .. · 2 .. .. 
.-·· .. - .... 
Comments: Nu merous very large trees {36" + dbh) dominate this area. Open shrub layer, weedy ground layer. 
Ivy, clemat is climbing half the trees. 
City o f Tigard Urban Fores try Code Rc\'isions I Volume II I 383 
GROVE SITE #: 79 SIZE: 2.08 acres SCORE: 22 
DATE: 9/9/2010 LOCATION: 79th and Bonita MAP: 79 
FIELD STAFF: DB GOAL 5 SITE? Yes PHOTOS: 530 
Grove Description .··: .. · ·---· 
·,· ; 
.·.: 
Mixed Douglas fir and b ig leaf maple. Large trees. Also some large western redcedar. Understory dominated by English ivy 
and a variety of invasives/escaped ornamentals. Scattered vine maple. One house in center but little escaped ornamentals. 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturity/Tree size 
Scenic ~nd natural ,·a lues increase 
wi th age; malurc lrccs me diniculi 10 >50% of trees have > 25-50% of trees have <25% of trees have > 
cptacc 14'' dbh ./ > 14'' dbh 14" dbh ! 
Grove size I 
Vitality, resilience of grove generally 
increases with Sil.C > 5 acres in size ./ 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
General condition and signs of threats, low potential threats; high disturbance; or 
dicback, ihrcats, disturbance disturbance ./ invasive species invasives dominate 
Visibility Vi sible from a11erial Visible from local 
Groves clearly visible from public street or public street or private Not visible from 
lands have greater value 
./ park/open space common open space street or open space 
Screening/Buffering Between industrial or 
I roves may serve as land usc commercial uses and Between similar land 
butlers; depending on density, residential or open uses, or simi lar land No (or very limited) 
location, uses space uses ./ use characteristics buffer function 
Accessibility Some physical or 
Grcalcr access provides more legal access limits; or 
>pportunity lor public usc; but Unrestricted public part public, part Privately owned or 
inappropriate on private lots access private land ./ inaccessible 
Rarity 
Unusual features (e.g., large grove or Uncommon features 
tree size, or rare species) or Rare natura I or or combination of No uncommon 
hislorical value cultural features fea tures ./ features 
Educationai/Rec. Potential 
Accessible groves with unusual Accessibility and Accessibility and 
tcaturcs offer rccrcalional and/or Rarity are high or Rarity arc both Accessibility or 
ducational values medium medium ./ Rarity are low 
Wildlife Habitat Diverse stmcture, Good source of Provides few habitat 
Habilat functions for terrestrial species mix; high food, cover, territory functions, minimal 
species, connectivity, diversi ty connectivity; lg. size for wildlife ./ connectivity 
Existing Development Undeveloped Panially Developed, or 
Groves wi th development (< I unit per acre) developed ./ surrounded 
SUB-TOTALS 1 X5 4 X 3 5 X1 
TOTAlS 
... · - . 5 , .. .. -·- 12 5 
Comments: Ornamenta l manicured yard . Edges on south/ east excl uded: developed, fragmented. 
Iso lated from other habitats. 
CitY of Tiganl Urban Forr,try Code RcYi,ion' I \' olume II I .)H4 
GROVE SITE #: 81 SIZE: 3.08 acres SCORE: 36 
' 
DATE: 9/13/2010 LOCATION: Pinebrook MAP: 81 i 
FIELD STAFF: AS GOAL 5 SITE? Yes PHOTOS: 5717-8 
Grove Description .. . 
'· 
- < ;···· .i . . 
Evergreen forest dominated by Douglas fir, western redcedar, and bigleaf maple: scattered Oregon ash and red alder also 
present. The understory supports a variety of species including snowbeny, beaked hazelnut, red-osier dogwood . English ivy, 
Himalayan blackbeny, and herb-robert prevalent as well. 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturity/T r ee size 
Scenic and natural values increase 
with age; mature trees arc dillicult to >50% oftrees have > 25-50% of trees have <25% of trees have > 
replace 14' ' dbh ./ > 14'' dbh 14'' dbh 
Grove size 
Vitality, rcsiliance of grove generally 
increases with size >5 acres in size ./ 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
iencral condition and signs of threats, low potential threats; high disturbance; or 
lichack, threats, disturbance disturbance ./ invasive species invasives dominate 
. 
Visibility Visible from arterial Visible from local 
proves clearly visible from public st reet or public street or private Not visible from 
lands have greater value 
./ park/open space common open space street or open space 
Screening/Buffer ing Between industrial or 
!Groves may serve as land usc comcrcial uses and Between similar land 
buffers; depending on density, residential or open uses, or similar land No (or very limited) 
location, uses space uses ./ use characteristics buffer function 
Accessibility Some physical or 
Greater access provides •norc legal access limits; or 
npportunily for public use; but Unrestricted public part public, part Privately owned or 
inappropriate on private lots access ./ private land inaccessible 
Rarity 
Unusualli:<lturcs (e.g., large grove or Uncommon features 
tree size, or rare species) or Rare natural or or combination of No uncomtnon 
historical value cultural features ./ fea tures features 
Educational/Rec. Poten tial 
Accessible groves with unusual Accessibility and Accessibility and 
features ollbr recreational and/or Rarity are high or Rarity are both Accessibility or 
educational values medium 
-/ medium Rarity are low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
Habitat limctions for terrestrial species mix; high food, cover, territory functions, minimal 
·pccies, connectivi ty, diversity 
./ connectivity; lg. size for wildlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development -/ (< I unit per acre) developed surrounded 
SUBMTOTALS 3 X5 7 X3 0 X1 
TOTALs ·· 
. ..• ·· ... 
.. JS .• ... · . . . . · . . 1 ··.· 21 ·.· . .. .. :·: ... 
. 0 .··•·· . <·>·:> ·. . . · .. : .. · . . . . . .. 
Comments: Broadly linear grove centered on stream corridor between development. Some development sti ll 
possible near Schekla/Lady Apple intersection but stream and vegetated corridor should be protected under CWS regs. 
City of Tigard Urban ForcRtry Code Re,·isiom I Volume II I 385 
GROVE SITE #: 83 SIZE: 3.46 acres SCORE: 32 
DATE: 9/13/2010 LOCATION: 103rd and Canterbury MAP: 83 
FIELD STAFF: AS GOAL 5 SITE? Yes PHOTOS: 5726 
Grove Description 
... · ·: .. __ .... > 
Evergreen forest. Douglas tir with no vegetati on in understory. Single-age stand. 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturityffree size 
Scenic and natura l "alucs increase 
with age; mature trees are diflicu lt to >50% of trees have > 25-50% of trees have <25% of trees have > 
replace 
../ 14" dbh > 14'' dbh 14 .. dbh 
Grove size 
Vitality, rcsiliancc of grove genera lly 
increases with size >5 acres in size ../ 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extens ive dieback or 
General condit ion and signs of threats, low potential threats; hi gh disturbance; or 
tieback, threats, disturbance 
../ disturbance invasive species invasives dominate 
Visibility Visible from arterial Visible from local 
I roves clearly visible from publ ic street or publi c street or private Not visible from 
lands have greater "aluc park/open space ../ common open space street or open space 
Screening/Buffering Between industrial or 
I roves may serve as land usc comercial uses and Between simi lar land 
buffers; depending on density, residential or open uses, or similar land No (or very limited) 
locat ion, uses 
../ space uses use characteristics buffer function 
Accessibility Some physical or 
lc;reatcr access provides more legal access limits; or 
jopportun ity for public usc; but Unrestricted publ ic part pub! ic, part Pri vatel y owned or 
inappropriate on private lots 
../ access private land inaccessible 
Rarity 
Unusual features (e.g., large grove or Uncommon features 
tree size, or rnrc species) or Rare natural or or combinat ion of No uncommon 
historical value cultura l fea tu res features ../ features 
Educational/Rec. Potential 
Accessible groves with unusua l Accessibility and Accessib ility and 
rcaturcs otl'cr recreational and/or Rarity are high or Rarity are both Accessibil ity or 
~ucat ional va lues medium medium ../ Rarity are low 
Wildlife Habitat Di verse structure, Good source of Provides few habitat 
Habitat functions for terrestrial species mix; high food, cover, territory fu nctions, minimal 
~pccics , connect ivity, diversi ty connectivi ty; lg. size for wildlife 
../ connect ivi ty 
Existing Development Undeveloped Partially Developed, or 
Groves with development (< I unit per acre) ../ developed surrounded 
SUB-TOTALS 4 X5 3 X 3 3 X1 
TOTALS . ' . .... . 
. 20 ..... 9 3 
... . .. .· .. ·'·· .· 
' 
.. 
Comments: Single-age stand was likely pla nte d. Und e rsto ry m anaged . 
Contiguous to this a rea is a more mixed stand to the west. 
City of Tigard Urban l 'o rc~try Cock R c,· i ~ion~ I \ 'olumc 11 I .)8o 
GROVE SITE #: 86 SIZE: 18.25 acres SCORE: 32 
DATE: 9/13/2010 LOCATION: 1 09th (west) MAP: 86 
FIELD STAFF: AS GOAL 5 SITE? No PHOTOS: 5722, 5725 
. Grove Description 
., 
... · ...•. ; .<f 
Mixed forest dominated by Douglas fir, bigleaf maple, and with a few scattered Scouter willow. The understory is a 
variety of native and invasive species. Some buffering between high and low-den sity residential uses and Highway 99. 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturityffree size 
Scenic and naturnl values increase 
\'ith age; mature trees arc dinicult to >50% of trees have > 25-50% of trees have <25% of trees have > 
replace 
./ 14'' dbh ~ 14" dbh 14'' dbh 
Grove size 
Vitality, rl.-siliance or grove generally 
increases with size 
./ >5 acres in size 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some die back or Extensive dieback or 
General condition and signs of threats, low potential threats; high disturbance; or 
~icback, threats, disturbance disturbance ./ invasive species invasives dominate 
Visibility Visible from arterial Visible from local 
lmves clearly visible lrom public street or pub! ic street or private Not visible from 
lands have gr~-ater va lue park/open space ./ common open space street or open space 
Screening/Buffering Between industrial or 
I roves may serve as land usc comercial uses and Between similar land 
bulfcrs; depending on density, residential or open uses, or simi lar land No (or very limited) 
location, uses 
./ space uses use characteristics buffer function 
Accessibility Some physical or 
Greater accl.-ss provides more legal access limits; or 
)pportunity for public usc; but Unrestricted public part public, part Privately owned or 
inappropriate on private lots access private land ./ inaccessible 
Rarity 
Unusual features (e.g., large grove or Uncommon features 
tree size, or rare sp<.'Cies) or Rare natural or or combination of No uncommon 
historical value cultural features features ./ features 
Educationai/Rec. Potential 
i\cccssible groves with unusual Accessibility and Accessibility and 
features ollcr recreational and/or Rarity are high or Rari ty are both Accessi bility or 
~ducational values medium medium 
./ Rarity are low 
Wildlife Habita t Diverse structure, Good source of Provides few habitat 
Habitat functions lor terrestrial species mix; high food, cover, territory functions, minimal 
species, connectivity, diversity connectivity; lg. size 
./ for wildlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development ./ (<l unit per acre) developed surrounded 
SUB-TOTALS 4 X5 3 X3 3 X1 
TOTALS .· .. 20 9 · 3 . "::: .... < ..  .. . · .· .. 
Comments: English ivy has overwhelmed the herb layer and has cl imbed high in trees. Some heavy Himalayan blackberry 
cover as well. May be developable. 
City of Tigard Urban Forestry Code Rc,·isions I Volume II I 387 
GROVE SITE #: 86a SIZE: 4.12 acres SCORE: 30 
DATE: 9/13/2010 LOCATION: 1 09th (east) MAP: 86a 
FIELD STAFF: AS GOAL 5 SITE? No PHOTOS: 5723-24 
. Gro_ve ·Description .. '' · .··. ·:.::c : .. : ._- · · 
.. 
. . :.:' ' 
Mix ed forest dominated by Douglas fir, bigleaf maple, with a few western redcedar. Saskatoon serviceberry, poison oak , 
dull Oregon grape, English holly, snowberry and beaked hazelnut are the most common shrub species. The understory 
762 
Function/ Characteri stic HIGH MEDIUM LOW 
Grove maturityffree size 
Scenic and natural va lues increase 
ll'ith age; mature trees arc ditlieult to >50% of trees have > 25-50% of trees have <25% of trees have > 
replace 
-/ 14" dbh > 14'' dbh 14'' dbh 
Grove size I 
Vitality, rcsiliance of grove generally 
increases with size >5 acres in size -/ 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dicback or Extensive dieback or 
General condition and signs or threats, low potential threats; high disturbance; or 
dicback, threats, disturbance 
-/ disturbance invasive species invasives domi nate 
Visibility Visible from arterial Visible from local 
}roves clearly visible ii·om public street or public street or pri vale Not visible from 
lands have greater value park/open space -/ common open space st reet or open space 
Scrcening/Bu ffering Between industrial or 
!Groves may serve ns land usc comercial uses and Between similar land 
bu!Tcrs; depending on density, residential or open uses, or simi lar land No (or very limited) 
location, uses space uses -/ use characteristics buffer function 
Accessibility Some physical or 
k;reatcr access pro,·ides more legal access limits; or 
)pportun ity for public usc; but Unrestricted public part public, pat1 Privately owned or 
inappropriate on private lots access private land -/ inaccessible 
Rarity 
Unusual teuturcs (e.g., large grove or Uncommon features 
tree size, or rare species) or Rare natural or or combination of No uncommon 
historical value cultural features -/ features features 
Educationai/Rec. Potential 
Accessible groves \\'ith unusual Accessibility and Accessibility and 
features offer recreational and/or Rarity are high or Rarity are both Accessibility or 
ducational va lues medium medium 
-/ Rarity arc low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
lhbitat functions for terrestrial species mix; high food, cover, territory functions, minimal 
~pccics, connectivity, diversity connectivity; lg. size 
-/ for wi ldlife conneclivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development (<I unit per acre) -/ developed surrounded 
SUB-TOTALS 2 xs 6 X3 2 X 1 
TOTALS · ''··· .. · · 10 
·· . .c.·.·.' .. • 18 .. .. 2 •' 
.. 
.. ,_, ,· . 
Comments: Grove of large fir (40"+ dbh) and bigleaf maple (14-20" dbh); a few western redcedar but more saplings. 
There are a few informal trails but no development. lnvasives generally at the margins . Buffering between low- and high-
density residential uses. 
CitY of Tigard Urban I 'or~,;trl' Code Rc\·i,;ions I \' olumc II I 38H 
. ------- · · -
GROVE SITE#: 89 SIZE: 1.21 acres SCORE: 26 
DATE: 8/30/2010 LOCATION: Golf course/behind church MAP: 89 
FIELD STAFF: DB,AS,TB GOAL SSITE? No PHOTOS: 5618 
. Grove Description .. ·· .. · .. ·· ... ·.·. , ~~ 7 
Douglas fir with Oregon white oak. Firs 20-42" dbh; Oak 20"; Parklike understory- mowed grass, ornamentals, rhododendrons. 
Areas in golf course similar. 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturityrTrcc size 
Scenic and natural values increase 
vith age; mature trees arc dinicult to >50% of trees have> 25-50% of trees have <25% of trees have > 
replace 
./ 14" dbh > 14" dbh 14" dbh 
Grove size 
Vitality, resilience of gro\'C generally 
increases with size >5 acres in size 2 to 5 acres in size ./ < 2 acres in size I 
Health Healthy: no visible Some dieback or Extensive dicback or ! 
lc;encral condition and signs of threats, low potential threats; high disturbance; or I 
tieback, threats, disturbance 
./ disturbance invasive species invasives dominate 
Visibility Visible From arterial Visible fromloeal 
Groves clearly visible from public street or pub! ic street or private Not visible from 
lands have greater value park/open space ./ common open space street or open space i 
Screening/Buffering Between industrial or 
Groves may serve as land usc commercial uses and Between similar land 
lbuflers; depending on density, residential or open uses, or similar land No (or very limited) 
location, ust..'S space uses use characteristics ./ buffer function 
Accessibility Some physical or 
ireater access provides more legal access limits; or 
)rportunity tbr public usc; but Unrestricted public part public, part Privately owned or I inappropriate on private lots access ./ !private land inaccessible 
Rarity 
Unusual leaturcs (e.g., large grove or Uncommon features 
rce si~c. or rare species) or Rare natural or or combination of No uncommon 
[historical value cultural features ./ features features 
Educationai!Rec. Potential 
Accessible groves with unusual Accessibility and Accessibility and 
features offer recreational and/or Rarity are high or Rarity are both Accessibility or 
educational values medium ./ medium Rarity are low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
Habitat functions fbr terrestria l species mix; high food, cover, territory functions, minimal 
~pccies, connectivity, diversity connectivity; lg. size for wildlife ./ connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development (<I unit per acre) developed ./ surrounded 
SUB-TOTALS 2 X5 4 X3 4 X1 
TOTA.~ .· .. ··• ·• •... 10 I 12 4 · ~· .... .-· ... ~ .. · ,,. ' 
Comments: Not in position to provide buffer. Access limited, grove size < 2 acres. Observed white-breasted 
and red-breasted nuthatches, northern f licker 
City of Tiganl Urban Forestry Code ReYisions I Volume II I 389 
GROVE SITE#: 90 SIZE: 2.53 acres SCORE: 22 
DATE: 8/30/2010 LOCATION: Churchhill Ct, S of Ashford MAP: 90 
FIELD STAFF: DB,AC,TB GOAL 5 SITE? No PHOTOS: 5610-5612 
Grove Description 
Mixed Evergreen-Deciduous Forest; Douglas !lr- bigleaf maple codominants with few western red cedar, black cottonwood, and 
a few ornilmentals. Understory is a mix of native and introduced shrub species . 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturity/Tree size 
Scenic and natural values increase 
wi th age; mawre trees arc di flicult 1<> >50% of trees have > 25-50% of trees have <25%oftrees have > 
replace 
./ 14 .. dbh > 14'' dbh 14" dbh 
Grove size 
Vitality, resilience or gro,·c generally 
increases with si:!.C >5 acres in size ./ 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
General condition and signs or threats, low potential threats; high disturbance; or 
Jicback, threats, disturbance disturbance ./ invasive species invasives dominate 
Visibility Visible from arterial Vis ible from local 
Groves clearly visible lrom public street or public st reet or private Not visible from 
lands hoYc greater value park/open space ./ common open space street or open space 
Screening/Buffering Between industrial or 
iroves may serve as land usc comercial uses and Between simi lar land 
butlers; depending on density, residential or open uses, or similar land No (or very limited) 
locution, uses space uses ./ use characteristics buffer function 
Accessibility Some physical or 
ireatcr access provides more legal access limits; or 
!opportunity ror public use; but Unrestricted public part public, part Privately owned or 
inappropriate on private lots access !private land ./ inaccessible 
Rarity 
Unusual features (e.g., large grove or Uncommon features 
tree size, or rare species) or Rare natural or or combination of No uncommon 
historical value cultural features features ./ features 
Educationai/Rec. Potential 
1\cccssiblc groves wi th unusua I Accessibility and Accessibility and 
lcaturcs otTer rec,reational and/or Rarity are high or Rarity are both Accessibility or 
~ducationalvalucs medium medium 
./ Rarity are low 
Wildlife Habitat Diverse stn.tcture, Good source of Provides few habitat 
l·tabitat functions for terrestrial species mix; high food , cover, tetTitory functions, minimal 
species, conn~-ctivity, diversity connectivity; lg. size for wildlife 
./ connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development (< I unit per acre) developed ./ surrounded 
SUB-TOTALS 1 X5 4 X3 5 X1 
TOTALS . .... · 5 12 5 ..... 
Comments : Grove is surrounded by residential development, isolated . Well-developed shrub layer in areas. 
Generally low habitat fuuntions, but provides some songbird habitat. Variety of introduced shrubs, e.g., 
Himalayan blackberry, sweet cherry. 
City of T igard Urban l'orcstry Cmle Rc,·isions I \ 'olumc II I 3911 
GROVE SITE#: SIZE: 1.29 acres 24 
i,DATE: LOCATION: ( 6th Avenue 91 
I FIELD STAFF: AS IGOAL 5 SITE? PHOTOS: ls737 Yes 
Grove Description ·.·• .. :._:· .. ·;·' ..... ~ :· 
Evergreen grove dominated by Douglas fir and westem redcedar. A few scattered oaks also present. 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturity/Tree size 
Scenic and nalurul values increase 
wilh age; ma1urc lrecs arc diflicull lo >SO% of trees have > 25-50% of trees have <25% of trees have > 
replace 
./ 14'' dbh > 14'' dbh 14'' dbh 
Grove size 
Vilalily, rcsiliancc of grove generally 
incr~'USCS wilh si~.c >5 acres in size 2 to 5 acres in size ./ < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
General condilion and signs c>f threats, low potential threats; high disturbance; or 
dicback, lhrcals, dislurbancc disturbance ./ invasive species invasives dominate 
Visibility Visible from arterial Visible from local 
proves clearly visible fwm public street or public street or private Not visible from 
lands have gre;ller value park/open space ./ common open space street or open space 
Screening/Buffering Between industrial or 
ttJrovcs may serve as land usc comercial uses and Between similar land 
hullers; depending 011 dcnsily, residential or open uses, or similar land No (or very limited) 
local ion, uses space uses ./ use characteristics buffer function 
Accessibili ty Some physical or 
irealcr access provides more legal access limits; or 
opportunity fi.)r public usc; but Unrestricted public part public, part Privately owned or 
inapproprinlc on privale lois access private land ./ inaccessible 
Rarity 
Unusuallcaturcs (e.g .. large grove or Uncommon features 
lrce size, or rare species) or Rare natural or or combination of No uncommon 
historical value cultural features features ./ features 
Educationai/Rec, Potential 
Accessible groves with unusual Accessibility and Accessibility and 
fcalures otler recreational and/or Rarity are high or Rarity arc both Accessibility or 
cducalional values medium medium ./ Rarity are low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
Habilat thncl ions for lerrcstrinl species mix; high food, cover, territory functions, minimal 
species, conncclivily, diversity connectivity; lg. size ./ for wildlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development (< I unit per acre) ./ developed surrounded 
SUB-TOTALS 1 xs 5 X3 4 X 1 
TOTALS 5 15 i 4 .-. 
.. 
Comments: Small grove on residential lot. Lot is likely divisible. Visibility from right-of-way is limited. 
City of Tigard Urban Forestry Code Re,·isions I Volume II I 391 
GROVE SITE #: 92 SIZE: 2.27 acres SCORE: 22 
DATE: 8/30/2010 LOCATION: 1-5, S. Upper Boones Ferry MAP: 92 
FIELD STAFF: DB,AS,TB GOALS SITE? No PHOTOS: 5606-7 
. Grove Description 
' . . ... 
.... .-:. ·· .. : 
.. 
Douglas fir (25-30" dbh) grove with sparse understory; scattered maples and other deciduous trees, cut blackberry, introduced grasses, 
heavy ivy at south end of site, evidence of herbicide use. 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturity/Tt·ee size I 
Scen ic and natural values incrc:~sc 
\\'ith age; mature trees arc di !lieu It to >50% of trees have > 25-50% of trees have <25% of trees have > 
replace ./ 14'' dbh > 14" dbh 14" dbh 
Grove size 
Vitality, resilience of grove gcncmlly 
increases with silc > 5 acres in size ./ 2 to 5 acres in size < 2 ncres in size 
Health Healthy: no visible Some dieback or Extensive diebnck or 
General condition and signs of threats, low potential threats; high disturbance; or 
~ieback , threats, disturbance disturbance invasive species ./ invash'es dominate 
Visibility Visible from arterial Visible from local 
"Jroves clearly visible li·onl public street or public street or private Not visible from 
lands have greater value ./ park/open space common open space street or open space 
Screening/Buffering Between industrial or 
inwcs may serve as land usc commercial uses and Between similar land 
buO'crs; depending on density, residential or open uses, or similar land No (or very limited) 
location, uses space uses ./ use characteristics buffer function 
Accessibility Some physical or 
lr,rcater access provides more legal access limits; or 
!opportunity for public usc; but Unrestricted public part public, part Privately owned or 
inappropriate on private lots access private land ./ inaccessible 
Rarity 
Unusual features (e.g., large grove or Uncommon features 
tree size, or rare species) or Rare natural or or combination of No uncommon 
historical value cultural features features ./ features 
Educationai/Rec. Potential 
Accessible groves with unusual Accessibility and Accessibility and 
features otler recreational and/or Rarity are high or Rarity are both Accessibility or 
educat ional values medium medium ./ Rarity are low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
Habitat funct ions ror terrestrial species mix ; high food, cover, territory functions, minimal 
species, connectivity, diversity connectivity; lg. size for wildlife ./ connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development (< I unit per acre) developed ./ surrounded 
SUB~ TOTALS 2 X5 2 X3 6 X1 
TOTALS . 10 .. .. , ·,. ,,·· ··. 6 . .•. :6 ... _ 
.... . ' 
Comments: Broad linear grove along western edge of 1-5 at Upper Boones Ferry Road . Minimal publ ic access, 
buffers hotel and commercial uses from 1-5. 
City of Tigaru Urban l'orc,try Couc Rc,·i,ions I \ 'olumc II I .>'!2 
GROVE SITE #: 93 SIZE: 21 .15acres SCORE: 40 
DATE: 9/13/2010 LOCATION: Durham/74th Avenue MAP: 93 
FIELD STAFF: AS GOAL S SITE? Yes PHOTOS: 5735-6, 5738-9 
Grove Description . ·_. 
Douglas fir/wes tern redcedar forest with a few red alder, bigleaf maple, and Oregon ash. Understory dominants include 
Saskatoon scrviccbcrry,beaked hazelnut, and maple saplings. Himalayan blackbeny common and frequently heavy at edges. 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturity/Tree size 
Scenic nnd natural values increase 
\\'ith age; mature trees arc di!Hcuh to >50% oF trees have > 25-50% of trees have <25% oftrccs have > 
replace 
./ 14' ' dbh > 14'' dbh 14"dbh 
Grove size 
Vitality, resiliance ofgnwe generally 
increases with size 
./ >5 acres in size 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or • 
General condition and signs of threats, low potential threats; high disturbance; or 
dicback, threats, disturbance disturbance ./ invasive species invasi ves dominate 
Visibility Visible from arterial Visible from local 
proves clearly visible fhnn public street or public street or private Not visible from 
lands have greater value 
./ I park/open space common open space street or open space 
Screening/Buffering Between industrial or 
Groves may serve as l:•nd use comercial uses and Between similar land 
hulrers; depending on density, residential or open uses, or similar land No (or very limited) 
location, uses space uses ./ use characteristics buffer function 
Accessibility Some physical or 
'lrcater access provides more legal access limits; or 
ppportunity for public use; but Unrestricted public part public, part Pri vately owned or 
inappropriate on private lots access ./ private land inaccessible 
Rar ity 
Unusual features (e.g., large grove or Uncommon features 
tree size, or rare species) or Rare natural or or combination of No uncommon 
tistorical value cultural features ./ features features 
EducationalfRec. Potential 
Accessible grovL'S with unusual Accessibility and Accessibility and 
features oflcr recreational and/or Rarity are high or Rarity are both Accessibility or 
ptucational values medium 
./ medium Rari ty are low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
Habitat !'unctions for tenestrial species mix; high food, cover, territory functions, minimal 
fSJlCcics, connectivity, divers ity 
./ connectivity; lg. size for wildlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development ./ (< I unit per acre) developed surrounded 
SUB-TOTALS 5 X5 5 X3 0 X1 
TOTALS , .. .. .. · . .25 .. ·. . 15 
.. 
0 
Comments : Grove is a combination of public and private ownership, but much the area lies within the vegetated corridor 
and work within it will be regulated. Habitat values are high due to large size of grove, diversity of habitat types, and 
proximity to water. Invasive knotweed infestation at t he end of 76th Avenue 
City of Tigard Urban l'orcstry Code Revisions I Volume II I 393 
---------
i GROVE SITE#: 95 SIZE: 3.76 acres SCORE: 28 
DATE: 9/13/2010 LOCATION: Dover Ct. MAP: 95 
FIELD STAFF: AS GOAL 5 SITE? Yes PHOTOS: 5728-9 
Grove Description 
. 
Mixed forest along drainage leading to Tualatin River. Dominant trees are Douglas fir, bigleaf maple, Oregon ash, and red 
alder. Snowberry is the dominant understory shrub, accompanied by a variety of native and non-nati ve shrubs and herbs . 
Himalayan blackberry ranges from absent to heavy, with heaviest infestations where light is greatest (edges, deciduous trees) . 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturityffree size 
Scenic and nmural vah•cs increase 
\\'ilh age; mature trees arc dilncult to >50% of trees have > 25-50% of trees have <25% of trees have > 
replace 
./ 14" dbh > 14" dbh 14'' dbh 
Grove size 
Vitality, rcsiliancc of grove generally 
increases 1\'ilh size >5 acres in size ./ 2 to 5 acres in size < 2 acres in size 
Health Hea lthy: no visible Some dieback or Extensive dieback or 
General condition and signs of threats, low potential threats; high disturbance; or 
licback, threats, disturbance disturbance ./ invasive species invasives dominate 
Visibili ty Visible from nrterial Visible from local 
Groves clearly visible from public st reet or public street or private Not visible from 
lands have greater va lue 
./ park/open space common open space street or open space 
Screening/Buffering Between industrial or 
)roves may serve as land usc comercial uses and Between similar land 
bull'crs; depending on density, residential or open uses, or similar land No (or very limited) 
location, uses space uses use characteristics ./ buffer function 
Accessibility Some physical or 
Greater access provides more legal access limits; or 
opportun iiy for public usc; but Unrestricted public part public, part Privately owned or 
inappropriate on private lots access ./ private land inaccessible 
Rarity 
Unusual features (e.g., large grove or Uncommon features 
tree size, or rare species) or Rare natural or or combination of No uncommon 
historical va lue cultural features features ../ features 
Educationai/Rec. Potential 
Accessible groves with unusual Accessibility and Accessibility and 
features ofl'cr recreational and/or Rarity are high or Rarity are both Accessibility or 
~lucational values medium medium 
./ Rarity are low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
Habitat functions tor terrestrial species mix; high food, cover, territory functions, minimal 
pecies, connect ivi ty, diversity connectivity; lg. size 
./ for wi ldlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development (<I unit per acre) ./ developed surrounded 
SUB-TOTALS 2 X5 5 X3 3 X1 
TOTALS 10 15 3 - . 
Comments: Th is grove lies at the edge of the city limits; a larger portion lies outside the boundary. 
Most of the grove has limited visibility from public rights-of-way, and access from public oreas is difficult . 
Areas of deciduous tree cover have higher cover of invasive species in the understory, particularly Himalayan blackberry. 
City of Tigard Urban I 'or~stry Code Rc,·isions I \' olumc II I .>9-1 
. GROVE SITE #: 96 SIZE: 6.50 acres SCORE: 30 
I 
DATE: 9/13/2010 LOCATION: Durham Road/Copper Creek MAP: 96 
. 
FIELD STAFF: AS GOAL 5SITE? Yes PHOTOS: none 
_Groye Description . . ·' .. . ·': , . I 
.. 
. . ' . .'.·.1 
Mixed forest along small drainage in a draw between developments. Douglas fir, western redccdar and bigleaf maple 
are the dominant trees, with beaked hazelnut and a largely native shrub community underneath outside landscaped yards. 
Herbaceous species include sword fern , lady fern. Some English ivy and Himalayan blackberry, especially at margins. 
Function/ Characteristic HIGH MEDIUM LOW i 
Grove maturity/Tree size ! 
I 
Scenic and natural values increase I 
I 
with 3!;C; mature trees are dillicuh to >50% of trees have > 25-50% of trees have <25% of trees have> i 
replace 
./ 14'' dbh > 14'' dbh 14" dbh 
Grove size 
Vitality, rcsiliuncc Of!,;rovc generally 
increases with size 
./ >5 acres in size 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
lr,encral condition and signs of threats, low potential threats; high disturbance; or 
licback, threats, disturbance disturbance ./ invasive species invasives dominate 
Visibil ity Visible from arterial Visible from local 
proves clearly visible lrmn public street or public street or private Not visible from 
lands have greater value 
./ park/open space common open space street or open space 
Scr eening/Buffer ing Between industrial or 
tJrovt.>s may serve as land use comercial uses and Between similar land 
buffers; depending on density, residential or open uses, or similar land No (or very limited) 
location, uses space uses ./ use characteristics buffer function 
Accessibility Some physical or 
ireater access provides more legal access limits; or 
ppportunity tor public usc; but Unrestricted public part public, part Privately owned or 
inappropriate on private lois access private land ./ inaccessible 
Rar ity 
Unusual features (e.g., large grove or Uncommon features 
tree size, or rare species) or Rare natural or or combination of No uncommon 
~istorical value cultural features features ./ features 
Educational!Rec. Potential . 
t-\cct.'SSiblc gro,·es with unusual Accessibility and Accessibility and 
!'t:aturcs otTer recreational and/or Rarity are high or Rarity are both Accessibility or 
·ducational values medium medium ./ Rarity are low 
W ildlife H abitat Diverse structure, Good source of Provides few habitat 
Habitat functions for terre-~triul species mix; high food, cover, territory functions, minimal 
·pecies, connectivity, diversity connectivity; lg. size 
./ for wildlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development ( < l unit per acre) ./ developed surrounded 
SUB-TOTALS 3 X5 4 X3 3 X1 
TOTAlS .. . ...... .... . 15 .. ·.· . .· ·.· .. u · ... . 3 .: .• :· ..... ·,>.:<·.:.' . 
Comments: This grove will be landlocked when the development at the north end is completed. Mature trees with some 
top breakage. Himalayan blackberry is present where light penetration is greater . 
City of Tigard Urban f'orestry Code Revisions I Volume 11 I 395 
GROVE SITE#: 97 SIZE: 7.08 acres SCORE: 40 
DATE: 8/30/2010 LOCATION: Fanno Creek at Durham MAP: 97 
FIELD STAFF: DB,AS,TB GOAL 5 SITE? Yes PHOTOS: 5613-5616 
Grove Description .. · ... ·.·. 
Deciduous Fores t; Oregon ash - biglea f maple codom inants with some red a lder: s izes generally 18-32" dbh. 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturityffrce size 
Scenic nnd nawral va lues increase 
with age; mature trees are diflicuh to >50% of trees have > 25-50% of trees have <25% of trees have > 
rcplncc 
./ 14'' dbh > 14'' dbh 14 .. dbh 
Grove size 
Vi laii ly, ri..'S iliance of grove generally 
increases wi lh size 
./ >5 acres in size 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
General comlilion and signs or threats, low potential threats; high disturbance; or 
tieback, thrcals, dis!Urbancc 
./ di slurbance invasive species invasives dominate 
Visibility Visible fro m arterial Visible from local 
, roves clearly visible from public street or public street or priva te Not visible from 
lands have greater value park/open space ./ common open space street or open space 
Screening/Buffering Between industrial or 
Groves may serve ~s land usc comercial uses and Between simi lar land 
buflers; depending on dcnsily, residential or open uses, or similar land No (or very limited) 
localion, uses space uses ./ use characterist ics buffer function 
Accessibility Some physical or 
Grcalcr access provides more legal access I imits; or 
jopportun ity tor public usc; bul Unrestricted public part public, part Privately owned or 
inupproprialc on privalc lois access ./ private land inaccessible 
Rarity 
Unusual fca lurcs (e.g. , large grove or Uncommon features 
1rce size, tlr rare species) or Rare natural or or combi nat ion of No uncommon 
hisloricalvo luc cultural features ./ features features 
Educational/Rec. Potential 
1\cccssible groves wil h unusual Accessibi lity and Accessibility and 
tea lures offer rccrcalional and/or Rarity are high or Rarity are both Accessibil ity or 
educational va lues medium 
./ medium Rarity are low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
Hahi lal functions for tcn·cslrial species mix; high food, cover, terri tOJy functions, minimal 
species, conncctivily, diversity 
./ connectivi ty; lg. si ze for wi ldli fe connectivi ty 
Existing Development Undeveloped Partially Developed, or 
Groves with development ./ (< I unit per acre) developed surrounded 
SUB-TOTALS 5 X5 5 X3 0 X1 
TOTALS .. 
.. 
25 • 15 0 
Comments: Grove is part of ri parian forest along Fanno Creek. One large open-growth oak on north side of site. 
Good quality habitat, with interspersed habitat types, riparian and wetlands and undeveloped uplands. West edge of site 
is publicly owned, with school adjacent. Visibility somewhat limited: distant view from Durham and visi ble from 
commut er rail. 
City of Tigard Urban Fores try Code Rc,·isions I \' olumc 11 I 3% 
GROVE SITE #: 99 SIZE: 5.89 acres SCORE: 34 
DATE: 8/30/2010 LOCATION: SW 92nd/ N of Cook Park MAP: 99 
FIELD STAFF: DB,AC,TB GOAL 5SITE? Yes PHOTOS: 5622-3 
Gr()Ve D~scription · .  •· -~ - . - .... . .. -, .. o• • • 0 .·.o•.. / >:< .. 
0. 
Dominant trees are willow, red alder, Oregon ash, black cottonwood, with scattered Oregon white oak up hill. 
Himalayan blackberry dominates the understory. 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturityffrcc size 
Scenic and nntural va lues increase 
\\'ith ngc; mature trees arc di nicult to >50% of trees have > 25-50% of trees have <25% of trees have > 
replace 14'' dbh -/ > 14'' dbh 14'' dbh 
Grove size 
Vitality, resilience of grove generally 
increases with size 
-/ > 5 acres in size 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
General condition and signs of threats, low potential threats; high disturbance; or 
tieback, threats, disturbance disturbance -/ invasive species invasives dominate 
Visibility Visible from arterial Visible from local 
Jrovcs clearly visible from public street or public street or private Not visible from 
lands have greater value .,/ park/open space common open space st reet or open space 
Screening/Buffering Between industrial or 
lr. roves moy serve as land usc commercial uses and Between similar land 
!buffers; depending on density, residential or open uses, or similar land No (or very limited) 
location, uses space uses -/ use characteristics butTer function 
Accessibility Some physical or 
Greater access provides more legal access limits; or 
!opportunity for public usc; but Unrestricted public part public, part Privately owned or 
inappropriate on private lots access private land ,/ inaccessible 
Rarity 
Unusual features (e.g., large grove or Uncommon features 
tree size, or rare species) or Rare natural or or combination of No uncommon 
tistorical value cultural features -/ features features 
EducationaURec. Potential 
Accessib le groves with unusual Accessibility and Accessibility and 
features offer recreational and/or Rarity are high or Rarity are both Accessibility or 
ducational values medium medium -/ Rarity are low 
Wildlife Habitat Diverse structure, Good source of Provides few habitat 
Habitat functions for terrestrial species mix; high food, cover, territory functions, minimal 
·pccics, connecti,·ity, diversity -/ connectivity; 1<>. size for wildlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development .,/ (<1 unit per acre) developed surrounded 
SUB-TOTALS 4 X5 4 X3 2 X1 
TOTAL$/~··· \~ > , . . >20 ·· 12 . ,o ··· 2 ( ... ' : . <; · . . · / .. ' ... ·.· 
·' · 
. ' 
... 
.. :.,.,. 
Comments: 
City of Tigard Urban Forestry Code RcYisions I Volume 11 I 397 
GROVE SITE#: 99a SIZE: 3.21 acres SCORE: 26 
DATE: 8/30/2010 LOCATION: east of 92nd, n of Cook Park MAP: 99a 
FIELD STAFF: DB,AS,TB GOAL 5 SITE? Yes PHOTOS: 5622-23 
- Grove Description . .· .· 
. · .. ·. -· . ·· ,· _. , _ _ .'-'"' 
Dominant riparian trees are red alder, Oregon ash, willow, with some Douglas fir and Oregon white oak farther up the hillslope. 
Diverse: riparian habitats, adjacent wetlands, open space (Cook Park). Understory with lots of reed canarygrass 
and Himalayan blackberry 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturity/Tree size 
Scenic and natural values increase 
with age; mature trees ore di11icult to >SO% of trees have > 25-50% of trees have <25% of trees have > 
replace 14'" dbh ::: 14 .. dbh ./ 14" dbh 
Grove size 
Vitality, resilience of grove generally 
increases with size >5 acres in size ./ 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive diebaek or 
lr;cncrul condition and signs of threats, low potential threats; high disturbance; or 
tieback, threats, disturbance disturbance ./ invasive species invasives dominate 
Visibility Visible from arterial Visible from local 
)ro,·cs clearly visible trom public street or public street or private Not visible from 
lands have greater value 
./ park/open space common open space street or open space 
Screening/Buffering Between industrial or 
Groves may serve as land usc commercial uses and Between similar land 
buffers; depending on density. residential or open uses, or simi lar land No (or vety limited) 
location, uses space uses ./ use characteristics buffer function 
Accessibility Some physical or 
!Greater access provides more legal access limits; or 
1pportunity tbr public usc; but Unrestricted public part public, part Privately owned or 
inappropriate on private lots access ./ private land inaccessible 
Rarity 
Unusual features (e.g., large grove or Uncommon features 
tree size, or rare species) or Rare natural or or combination of No uncommon 
historical value cultural features features ./ features 
Educationai/Rec. Potential 
Acccssihte groves with unusual Accessibility and Accessibility and 
!i:aturcs oflcr recreational and/or Rarity are high or Rarity are both Accessibility or 
·ducational val11es medium medium ./ Rarity are low 
Wildlife Habitat Diverse structu re, Good source of Provides few habitat 
Habitat functions for terrestrial species mix; high food , cover, territory functions, minimal 
species, connectivity, diversi ty connectivity; [g, size ./ for wildlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development ( < l unit per acre) ./ developed surrounded 
SUB~ TOTALS 1 X5 6 X3 3 X1 
TOTALS ',. .·. 
. __ ,.:_ · . . . · .· .5 .·. I 18 3 .: 
Comments : 
City of Tigard Urban 1:orcstry Code Rc,·isions I Volume II I 3'!H 
GROVE SITE #: 100 SIZE: 15.39 acres SCORE: 44 
DATE: 9/13/2010 LOCATI ON: Tualatin R. corridor MAP: 100 
FIELD STAFF: AS GOAL SSITE? Yes PHOTOS: 5731-2 
Grove Description 
... · . 
Mixed forest dominated by Douglas tir and red alder with subdominants including Oregon ash, bigleaf maple, and a few 
westem redcedar. The understory supports a variety of native shrubs and groundcover but most areas have moderate to 
, heavy infestations of invasive species such as Himalayan blackberry, English ivy, and reed canarygrass. 
' 
Function/ Characteristic HIGH MEDIUM LOW 
Grove matu rityffree size 
Scenic and n~turnl values increase 
with age; mature trees are dirticult to >50% of trees have > 25-50% of trees have <25% of trees have > 
replace 14" dbh ..,. > 14"' dbh 14" dbh 
Grove size 
Vitality, rcsiliancc or grove generally 
increases with size .; >5 acres in size 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visible Some dieback or Extensive dieback or 
r.encral condition and signs or threats, low potential threats; high disturbance; or 
lieback, thrt-ats, disturbance disturbance ..,. invasive species invasives dominate 
Visibility Visible from arterial Visible from local 
iroves clearly visible from public street or public street or private Not visible from 
land~ hn,·c greater value ..,. park/open space common open space street or open space 
Scrcening/Bu ffering Between industrial or 
Groves may serve as land usc comercial uses and Between similar land 
burfcrs; depending on density, residential or open uses, or similar land No (or very limited) 
location, uses space uses ..,. use characteristics buffer function 
Accessibility Some physical or ! 
rJrcater access provides more legal access limits; or 
opportunity ror public usc; but Unrestricted public part public, part Privately owned or 
inappropriate on private lots ..,. access private land inaccessible 
Rarity 
Unusual features {e.g., large grove or Uncommon features 
tree size, or rare sp<.-cics) or Rare natural or or combination of No uncommon 
I historical value ..,. cultural features features features 
Educational/Rec. Potential 
Accessible groves with unusual Accessibility and Accessibility and 
fc<ttures o11cr recreational andfor Rarity are high or Rarity are both Accessibility or 
xlucntional valuL-s ..,. medium tnedium Rarity are low 
Wildlife Ha bitat Diverse structure, Good source of Provides few hab.itat 
llabitat limctions for terrestrial species mix; high food, cover, territory functions, minimal 
species, connectivity, diversity ..,. connectivity; lg. size for wildlife connectivity 
Existing Development Undeveloped Partially Developed, or 
Groves with development ..,. (<I unit per acre) developed surrounded 
SUB-TOTALS 7 X5 3 X3 0 X1 
TOTALS ,.• : 35 . 9 0 
Comments: This grove lies within the Tualatin River floodplain. Some tree mortality is evident; some trees lack tops but 
in others the reason for mortality is unclear. Corridor is about N120 feet wide from the river to the edge of adj. development. 
Trees range from 6" to 40"+ dbh. Beehive in large cedar snag. Forest structure is mixed age classes. 
City of Tigard Urban Forestry Code Revisions I Volume II I 399 
GROVE SITE #: 101 SIZE: 19.91 acres SCORE: 46 
DATE: 9/13/2010 LOCATION: Cook Park MAP: 101 
FIELD STAFF: AS GOAL 5 SITE? Yes PHOTOS: 5733-4 
Grove Description 
Mixed forest in Cook Park. This si te featu res large Douglas tir, bigleaf maple, ponderosa pine, Oregon oak, and Oregon ash. 
The understory com munity consists of osoberry, snowberry, thimbleberry, Oregon grape. and other riparian upland species. 
Engl ish ivy and Himalayan blackberry are present (and dominant), but the primary vi ne in the area is California dewberry. 
Function/ Characteristic HIGH MEDIUM LOW 
Grove maturity/Tree size 
Scenic and natu ral ,·nlucs increase 
with age: mature trees are diflicu lt to >50% of trees have > 25-50% or trees IHl\"C <25% of trees have > 
replace 14" dbh .,/ ?" 14""dbh 14'' dbh 
Grove size 
Vitality, rcsiliancc or grove genera lly 
increases with size .,/ >5 acres in size 2 to 5 acres in size < 2 acres in size 
Health Healthy: no visib le Some dieback or Extensive dieback or 
;cncral condition and signs or threats, low potential threats; hi gh disturbance; or 
licback, threats, disturbance disturbance .,/ invasive species invasives dominate 
Visibility Visible from arterial Visible from local 
I roves dearly visible ll·om public street or pub! ic street or pri vate Not visib le from 
lands have greater value .,/ park/open space common open space street or open space 
Scrcening!Bu ffering Between industrial or 
Groves may serve as land usc comercial uses and Between similar land 
!hurters; depending on density, residential or open uses. or si milar land No (or very limited) 
location, uses .,/ space uses use characteristics buffer function 
Accessibility Some physical or 
Jrcatcr access provides tntwc legal access limits; or 
)pportunity l()r public usc; but Unrestricted public part public, part Privately owned or 
inappropriate on private lots 
.,/ access private land inaccessible 
Rarity 
Unusual features (e.g., large grove or Uncommon features 
tree size, or rare species) or Rare natural or or combination of No uncommon 
historical value 
.,/ cultural features features features 
Educational/Rec. Potential 
Accessible groves wi th unusual Accessibility and Accessibility and 
lcaturcs orfer r~'Crcational and/or Rarity are high or Rarity are both Accessibility or 
educational values 
.,/ medium medium Rarity are low 
Wildlife Habitat Di verse structure, Good source of Provides few habitat 
Habitat functions lbr terrestrial species mix; high food, cover, territory functions, minimal 
species, connectivity, diversity .,/ connectivity; lg. size for wi ldl ife connectivity 
Existing Development lJ ndeveloped Partially Developed, or 
Groves with development .,/ (<l unit per acre) developed SUtTOUllded 
SUB-TOTALS 8 X5 2 X3 0 X1 
TOTALS 40 6 0 . -
Comments: Very large grove. Some areas under the canopy are developed for park use (picn ic tables, trails, etc.) 
Invasive species cover is gen erally light. Soft and paved trails throughout. 
CitT of Tigard Urban / ."orcstry Code Rc,- isions I Volume II I 400 
Appendix B: Impacted Taxlots and Significant Tree Grove 
Acreage 
City of Tigard Urban Forestry Project 
ESEE Analysis • Appendix 
Prepared by Winterbrook Planning 
November 2011 
City of Tigard Urban Forestry Code ReYisions I Volume II I 401 
Appendix B 
'-
c 
TLID 
1S125DA00200 
1S125DA00300 
1S125DA00400 
1S125DA00401 
1S125DA00500 
1S125DA00501 
1S125DA00601 
1S125DA00602 
1S125DA00700 
1S125DA00701 
1S125DA03001 
1S125DA03200 
1S125DA06700 
1S125DA06800 
1S125DA06900 
1S125DA07000 
1S125DA07001 
1S125DA07100 
1S125DA10500 
1S125DA11500 
1S125DA11600 
1S125DB03900 
1S125DB06300 
1S125DB09100 
1S125DB09300 
1S125DC00500 
1S125DC00600 
1S125DC00900 
1S125DC02200 
1S125DC04800 
1S125DC08000 
1S125DC08100 
1S125DC08200 
1S125DC08300 
1S125DC08400 
1S125DC08500 
1S125DC09000 
1S125DC09100 
1S125DC09600 
1S125DC09700 
1S125DD00500 
1S125DD00800 
1S125DD00900 
1S125DD01000 
1S125DD01100 
1S125DD01200 
1S125DD01800 
1S125DD02200 
1S125DD02300 
1S125DD02900 
1S125DD03000 
1S125DD03100 
1S125DD03200 
1S125DD03300 
1S125DD03400 
1S125DD03500 
IN TREE GROVE 
4534.51 
22112.24 
1417.12 
2917.43 
4220.71 
550.11 
4352.89 
2686.36 
575.97 
16084.15 
1901.52 
7152.01 
2425.80 
13267.08 
12805.93 
1566.59 
464.76 
16253.00 
4047.69 
221.46 
4018.52 
3294.06 
2086.62 
1308.79 
4133.83 
35662.14 
90758.52 
13977.68 
1437.38 
3888.02 
4919.00 
3660.82 
2228.47 
1627.57 
1469.75 
423.15 
762.00 
6.57 
3464.08 
165953.74 
58187.57 
1155.61 
6422.05 
2330.66 
1798.28 
5042.19 
71.09 
4390.91 
7.00 
45 .17 
143.28 
3587.17 
4219.42 
3039.52 
1682.90 
1623.79 
TAXLOT SIZE (sq ft) 
OUTSIDE TREE GROVE 
12453.89 
9686.56 
6423.68 
4923.37 
3620.09 
7290.69 
6537.11 
11252.84 
15105.63 
33.05 
15522.48 
10271.99 
15433.80 
6770.52 
7231.67 
9323.41 
8682.84 
10754.20 
11633.91 
8054.94 
4693.48 
27197.94 
11416.98 
8274.41 
11112.17 
25321.86 
31209.48 
30889.12 
7710.22 
467.98 
4664.20 
3744.38 
6047.93 
5342.03 
5499.85 
6110.85 
6643.20 
5220.63 
2634.32 
16998.26 
50712.43 
7556.39 
547.55 
5074.54 
6042.52 
3669.81 
8640.91 
8677.09 
7833.80 
8231.23 
8133.12 
6431.63 
5363.78 
6979.28 
8335.90 
7523.81 
TOTAL 
16988.40 
31798.80 
7840.80 
7840.80 
7840.80 
7840.80 
10890.00 
13939.20 
15681.60 
16117.20 
17424.00 
17424.00 
17859.60 
20037.60 
20037.60 
10890.00 
9147.60 
27007.20 
15681.60 
8276.40 
8712.00 
30492.00 
13503.60 
9583.20 
15246.00 
60984.00 
121968.00 
44866.80 
9147.60 
4356.00 
9583.20 
7405.20 
8276.40 
6969.60 
6969.60 
6534.00 
7405.20 
5227.20 
6098.40 
182952.00 
108900.00 
8712.00 
6969.60 
7405.20 
7840.80 
8712.00 
8712.00 
13068.00 
7840.80 
8276.40 
8276.40 
10018.80 
9583.20 
10018.80 
10018.80 
9147.60 
GROVE NUMBER GROVE TOTAL ACRES 
8 1.74 
8 1.74 
8 1.74 
8 1.74 
8 1.74 
8 1.74 
8 1.74 
8 1.74 
8 1.74 
8 1.74 
8 1.74 
8 1.74 
9 1.34 
9 1.34 
9 1.34 
9 1.34 
9 1.34 
9 1.34 
9 1.34 
8 1.74 
8 1.74 
14 3.06 
9 1.34 
9 1.34 
9 1.34 
14 3.06 
14 3.06 
12 6.43 
12 6.43 
12 6.43 
12 6.43 
12 6.43 
12 6.43 
12 6.43 
12 6.43 
12 6.43 
12 6.43 
12 6.43 
12 6.43 
12 6.43 
13 2.54 
13 2.54 
13 2.54 
13 2.54 
13 2.54 
13 2.54 
11 2.11 
12 6.43 
12 6.43 
12 6.43 
12 6.43 
13 2.54 
13 2.54 
13 2.54 
13 2.54 
13 2.54 
City of Tigard Urban Forestry Code Re,·isions I Volume II I 403 
TLID 
1S125DD03600 
1S125DD03700 
1S125DD03800 
1S125DD03900 
1S125DD04000 
1S125DD04100 
1S125DD04200 
1S125DD04300 
1S125DD04400 
1S125DD05700 
1S125DD05800 
1S125DD05900 
1S125DD06000 
1S125DD06100 
1S125DD06200 
1S125DD06300 
1S125DD06400 
1S125DD09000 
1S125DD09100 
1S125D009300 
1S125D009400 
1S125D009500 
1S125DD09600 
1S125DD09701 
1S125DD09800 
1S125DD10100 
1S125D010400 
1S125DD10500 
1S125DD10700 
1S125D010900 
1S133CD08600 
1S133C008700 
1S133CD13900 
1S133CD14800 
1S133CD17400 
1S133DA07200 
1S133DA07400 
1S133DA07500 
1S133DA09400 
1S133DB00104 
1S134AA00500 
1S134AA02200 
1S134AC01000 
1S134AC01200 
1S134AC02300 
1S134AC02601 
1S134AC02614 
1S134AC02615 
1S134AC02616 
1S134AC02623 
1S134AC03100 
1S134AC06600 
1S134AD06100 
1S134AD09700 
1S134CC01500 
1S134CC01700 
IN TREE GROVE 
2061.99 
4734.00 
4267.83 
3399.38 
2072.41 
2894.60 
6074.74 
7109.93 
2138.10 
75 .28 
2126.72 
1249.05 
1025.20 
11134.36 
3168.74 
3322.55 
47 .14 
2954.14 
3860.91 
131.54 
293.61 
929.91 
1921.09 
3101.59 
530.92 
22787.33 
15055 .76 
10407.99 
2737.16 
12940.00 
713 .38 
184.05 
474.73 
1254.85 
156371.60 
179463 .71 
9689.13 
12348.84 
5650.48 
31410.87 
44987.38 
6438.16 
458.50 
750.73 
207841.88 
165638.21 
1004.38 
2982.03 
2863.24 
4413.47 
566.55 
3818.86 
27469.23 
25881.81 
1426.31 
4351.48 
TAXLOT SIZE (sq ft) 
OUTSIDE TREE GROVE 
9263 .61 
6156.00 
5750.97 
7055 .02 
7510.79 
7124.20 
2201 .66 
5522 .47 
7880.70 
9072 .32 
7892 .08 
8334.15 
8558.00 
1933 .64 
7721.26 
6260.65 
12149.66 
8353.57 
6157.89 
9016.06 
8853.99 
8217.69 
7226.51 
5610.41 
9052.28 
1606.27 
190.24 
1353.21 
13815 .64 
999.20 
5993.43 
5547.82 
5188.07 
3101.15 
47489.20 
766223.89 
29950.47 
719.16 
1754.72 
184646.73 
114442.22 
182612.24 
8689.10 
8832.47 
98820.52 
69962.09 
11628.02 
8343.57 
11075 .96 
8654.53 
7709 .85 
2279.54 
99237 .64 
78662.19 
53023 .69 
460433.72 
TOTAL 
11325 .60 
10890.00 
10018.80 
10454.40 
9583.20 
10018.80 
8276.40 
12632.40 
10018.80 
9147.60 
10018.80 
9583.20 
9583.20 
13068.00 
10890.00 
9583.20 
12196.80 
11307.71 
10018.80 
9147.60 
9147.60 
9147.60 
9147.60 
8712.00 
9583 .20 
24393.60 
15246.00 
11761.20 
16552.80 
13939.20 
6706.81 
5731.87 
5662.80 
4356.00 
203860.80 
945687.60 
39639.60 
13068.00 
7405.20 
216057.60 
159429.60 
189050.40 
9147.60 
9583.20 
306662.40 
235600.30 
12632.40 
11325 .60 
13939.20 
13068.00 
8276.40 
6098.40 
126706.87 
104544.00 
54450.00 
464785.20 
GROVE NUMBER GROVE TOTAL ACRES 
12 6.43 
12 6.43 
12 6.43 
12 6.43 
12 6.43 
12 6.43 
12 6.43 
12 6.43 
12 6.43 
10 1.06 
10 1.06 
10 1.06 
10 1.06 
10 1.06 
10 1.06 
10 1.06 
10 1.06 
10 1.06 
10 1.06 
10 1.06 
10 1.06 
10 1.06 
10 1.06 
10 1.06 
10 1.06 
12 6.43 
13 2.54 
10 1.06 
13 2.54 
12 6.43 
31 3.68 
31 3.68 
31 3.68 
31 3.68 
31 3.68 
25 5.50 
25 5.50 
25 5.50 
25 5.50 
25 5.50 
17 1.66 
17 1.66 
19 9.71 
19 9.71 
19 9.71 
19 9.71 
19 9.71 
19 9.71 
19 9.71 
19 9.71 
19 9.71 
19 9.71 
19 9.71 
17 1.66 
32 5.81 
32 5.81 
City of 'l'iganl Urban Forestry CoJc RcYisions I \ 'olumc II I 404 
TLID 
1S134CC02000 
1S134CC02800 
1S134CC02900 
1S134CC04200 
1S134CC04300 
1S134CCOSOOO 
1S134CD00100 
1S134CD00200 
1S134CD00600 
1S134CD00700 
1S134CD00800 
1S134CD00900 
1S134CD01000 
1S134CD01100 
1S134CD01200 
1S134CD01202 
1S134CD06600 
1S134CD06700 
1S134DC03000 
1S134DC03002 
1S134DC03100 
1S134DC03102 
1S134DC03300 
1S134DC03400 
1S134DC03601 
1S134DC06700 
1S134DC11100 
1S134DD00900 
1S134DD01000 
1S134DD01600 
1S134DD01800 
1S135AA03600 
1S135AC01700 
1S135AC02550 
1S135AC90091 
1S135AD00900 
1S135AD00901 
1S135AD01100 
1S135AD01102 
1S135AD01104 
1S135AD01200 
1S135AD01400 
1S135AD01401 
1S135AD01600 
1S135AD01700 
1S135AD01702 
1S135AD03300 
1S135AD03400 
1S135DA02600 
1S135DA03900 
1S135DB08400 
1S135DB08900 
1S135DB09000 
1S135DB12600 
1S136AA00201 
1S136AA00301 
IN TREE GROVE 
231152.88 
633.67 
1411.42 
2014.14 
3401.97 
7957.57 
165010.93 
4170.34 
803.25 
4030.82 
4406.27 
2571.43 
3963.31 
12666.70 
19457.09 
8884.50 
600.95 
1444.95 
2107.17 
10803.60 
20304.38 
19269.69 
125857.05 
121160.13 
6022.71 
861.83 
15306.55 
229159.47 
175662.58 
16032.73 
19923.32 
1454.20 
64160.54 
2990.10 
100593.30 
36560.51 
2556.38 
19335.34 
1725.06 
6667.32 
6791.48 
11537.51 
5201.67 
74951.89 
26389.99 
5451.75 
943.48 
2148.64 
21818.12 
903.50 
7905.07 
112.45 
1215.18 
1807.26 
11574.11 
31277.72 
TAXLOT SIZE (sq ft) 
OUTSIDE TREE GROVE 
89224.53 
10691.93 
12092.18 
3648.66 
4874.43 
84825.23 
20554.67 
1492.46 
19669.95 
16442.38 
16066.93 
17901.77 
16509.89 
20438.90 
13212.91 
31190.70 
10724.65 
7267.05 
719682.03 
3734.30 
43916.81 
5667.19 
2848.97 
7545.91 
511.29 
2717.04 
12136.25 
410736.93 
160185.02 
53227.67 
26250.28 
33393.80 
59549.86 
80645 .10 
2643.90 
26165 .89 
12689.62 
4622.66 
25282.14 
16855.08 
76843 .72 
252000.49 
16578.33 
14781.71 
57680.81 
21119.85 
5154.92 
19631.36 
9545.08 
28717.30 
26942.93 
6857.15 
5754.42 
6469.14 
276793.09 
67167.88 
TOTAL 
320377.41 
11325.60 
13503.60 
5662 .80 
8276.40 
92782.80 
185565.60 
5662.80 
20473.20 
20473 .20 
20473 .20 
20473.20 
20473.20 
33105 .60 
32670.00 
40075 .20 
11325.60 
8712.00 
721789.20 
14537.90 
64221.19 
24936.88 
128706.02 
128706.04 
6534.00 
3578.87 
27442.80 
639896.40 
335847.60 
69260.40 
46173.60 
34848.00 
123710.40 
83635.20 
103237.20 
62726.40 
15246.00 
23958.00 
27007.20 
23522.40 
83635.20 
263538.00 
21780.00 
89733 .60 
84070.80 
26571.60 
6098.40 
21780.00 
31363 .20 
29620.80 
34848.00 
6969.60 
6969.60 
8276.40 
288367.20 
98445 .60 
GROVE NUMBER GROVE TOTAL ACRES 
32 5.81 
32 5.81 
32 5.81 
32 5.81 
32 5.81 
32 5.81 
35 5.50 
35 5.50 
35 5.50 
35 5.50 
35 5.50 
35 5.50 
35 5.50 
35 5.50 
35 5.50 
35 5.50 
35 5.50 
35 5.50 
36 30.97 
36 30.97 
36 30.97 
36 30.97 
36 30.97 
36 30.97 
36 30.97 
36 30.97 
36 30.97 
36 30.97 
33 3.79 
33 3.79 
33 3.79 
2 1.79 
22 4.90 
22 4.90 
22 4.90 
2 1.79 
2 1.79 
2 1.79 
2 1.79 
2 1.79 
2 1.79 
24 3.28 
24 3.28 
24 3.28 
24 3.28 
24 3.28 
2 1.79 
2 1.79 
22 4.90 
24 3.28 
22 4.90 
22 4.90 
22 4.90 
22 4.90 
11 2.11 
11 2.11 
City of Tigard Urban Forestry Code ReYisions I Volume II I 405 
TLID 
1S136AA00400 
1S136AA08500 
1S136AA08600 
1S136AA08700 
1S136AA08800 
1S136AD06300 
1S136AD06390 
1S136AD06505 
1S136AD06507 
1S136CD02200 
1S136CD04200 
1S136DA00100 
1S136DA00600 
1S136DA00900 
1S136DA00901 
1S136DA00902 
1S136DA01000 
1S136DA02100 
1S136DA02300 
1S136DA02400 
1S136DA02500 
1S136DA02600 
2S1010001100 
2S1010001200 
2S101AA06700 
2S101AA07100 
2S101AA07800 
2S101AB00100 
2S101AB00101 
2S101AB00200 
2S101AB00300 
2S101AB00301 
2S101AB00302 
2S101BA00101 
2S101BA00200 
2S101BB01201 
2S101CA00100 
2S101CC00100 
2S101DA00102 
2S101DA00103 
2S101DA00104 
2S101DA00105 
2S101DB00300 
2S101DB00400 
2S101DB00604 
2S101DC04500 
2S102BA00300 
2S102BA00304 
2S102BA00501 
2S102BA02000 
2S102BA02200 
2S102BA02300 
2S102BB00600 
2S102BB00700 
2S102BB00827 
2S102BB00828 
IN TREE GROVE 
24136.64 
1061.06 
6364.52 
6650.20 
2592.69 
28176.44 
558.07 
8284.32 
3774.46 
412 .55 
2017.86 
70240.78 
24824.28 
6038.96 
6019.06 
307801 .18 
5299 .03 
7201.58 
25350.47 
34776.64 
16814.90 
7184.80 
439440.16 
642001.71 
63975.57 
36270.15 
16967.86 
76701.47 
10876.68 
32281.73 
984.62 
3567.89 
4275 .60 
21943 .21 
281559.78 
53068.96 
598784.76 
478978.08 
18345.08 
86848.70 
38038.54 
25041.11 
32830.84 
11877.76 
7428.86 
9878.16 
33058.92 
11143 .04 
23716.98 
56000.43 
5863 .41 
13341 .18 
126431 .28 
85405.32 
2052.45 
1829 .78 
TAXLOT SIZE (sq ft) 
OUTSIDE TREE GROVE 
57320.56 
S908.54 
4961.08 
4675.40 
5248.11 
254527.96 
3362.33 
13931.28 
117757.94 
552363 .85 
23682.54 
359696.42 
80155.32 
150341.44 
24908.54 
43292.42 
52200.17 
32438.02 
320080.33 
159936.56 
21517.90 
45958.40 
137729.84 
477054.69 
3106.83 
6854.25 
15702.14 
62254.93 
13081 .32 
62679 .07 
38219.38 
12113.71 
11406.00 
725981.99 
163623.42 
128576.24 
453624.84 
48097.92 
207295.72 
2449.30 
331785.86 
176206.09 
102640.76 
75242 .24 
10950.59 
208357.44 
27489.48 
92529.76 
74728.62 
58126.77 
23321.79 
37624.02 
149739.12 
155917.08 
12757.95 
11238.22 
TOTAL 
81457.20 
6969 .60 
11325 .60 
11325 .60 
7840.80 
282704.40 
3920.40 
22215.60 
121532.40 
552776.40 
25700.40 
429937.20 
104979.60 
156380.40 
30927.60 
351093.60 
57499.20 
39639.60 
345430.80 
194713.20 
38332.80 
53143 .20 
577170.00 
1119056.40 
67082.40 
43124.40 
32670.00 
138956.40 
23958.00 
94960.80 
39204.00 
15681 .60 
15681.60 
747925.20 
445183.20 
181645.20 
1052409.60 
527076.00 
225640.80 
89298.00 
369824.40 
201247.20 
135471.60 
87120.00 
18379.45 
218235.60 
60548.40 
103672.80 
98445 .60 
114127.20 
29185 .20 
50965 .20 
276170.40 
241322.40 
14810.40 
13068.00 
GROVE NUMBER GROVE TOTAL ACRES 
11 2.11 
11 2.11 
11 2.11 
11 2.11 
11 2.11 
23 3.11 
23 3.11 
23 3.11 
23 3.11 
40 8.36 
40 8.36 
23 3.11 
30 9.61 
30 9.61 
30 9.61 
30 9.61 
30 9.61 
30 9.61 
30 9.61 
30 9.61 
23 3.11 
23 3.11 
62 25.28 
71 39.20 
44 2.99 
44 2.99 
44 2.99 
38 3.10 
38 3.10 
38 3.10 
38 3.10 
38 3.10 
38 3.10 
40 8.36 
40 8.36 
40 8.36 
62 25 .28 
71 39.20 
54 3.88 
54 3.88 
54 3.88 
54 3.88 
62 25.28 
62 25 .28 
62 25 .28 
62 25 .28 
3 12.47 
3 12.47 
3 12.47 
3 12.47 
3 12.47 
3 12.47 
3 12.47 
3 12.47 
3 12.47 
3 12.47 
City of Tigard Urban Forestry Cmk Rc,·isions I \'olume II I 4!1(> 
TLID 
2S102BB00829 
2S102BB00830 
2S102BB00831 
2S102BB00832 
2S102BB00900 
2S102BC02000 
2S102BC02001 
2S102BC02003 
2S102BC02006 
2S102BC02100 
2S102BC05700 
2S102BC06700 
2S102BC08600 
2S102DA00500 
2S102DA00600 
2S102DA00690 
2S102DC01300 
2S102DC01301 
2S102DC01304 
2S102DC01305 
2S102DC01400 
2S102DC01402 
2S102DC01500 
2S102DC01501 
2S102DC02500 
2S102DC02501 
2S102DC02900 
2S102DC03000 
2S102DD00100 
2S102DD00200 
2S102DD00300 
2S102DD00401 
2S102DD00811 
2S102DD00900 
2S102DD00901 
2S102DD00902 
2S102DD00903 
2S102DD03200 
2S102DD03800 
2S102DD05400 
2S103AA00100 
2S103AA00101 
2S103AA00200 
2S103AA00400 
2S103AA01913 
2S103AA02900 
2S103AB00100 
2S103AB00200 
2S103AB00403 
2S103AB00406 
2S103AB02300 
2S103AB02400 
2S103AB02500 
2S103AB02600 
2S103AB02700 
2S103AB04200 
IN TREE GROVE 
1356.33 
3008.62 
2728.03 
109110.77 
28166.09 
1379.61 
3563.38 
5977.81 
1965.78 
2214.99 
8504.77 
85302.94 
382.38 
5876.67 
13195.99 
8355.96 
40447.87 
15024.72 
4245.49 
1117.90 
23982.48 
11083.16 
26438.42 
3252.07 
35920.51 
4415.62 
2552.72 
3627.24 
57708.02 
49535.98 
59292.21 
73119.01 
5012.81 
8425.93 
19680.41 
17529.00 
8547.66 
O.D3 
12784.19 
25584.96 
27954.54 
77187.02 
212074.71 
3416.11 
2283.43 
8744.04 
100475.01 
146649.78 
40037.21 
83204.59 
3965.00 
1074.60 
2778.67 
1491.62 
5389.13 
88461.41 
TAXLOT SIZE (sq ft} 
OUTSIDE TREE GROVE 
11276.07 
7445.78 
9468.77 
38993 .23 
61131.91 
15608.79 
13860.62 
10139.39 
15022.62 
10853.01 
2820.83 
17498.66 
3102.42 
360462.93 
311761.61 
-79.56 
34039.73 
25050.48 
17534.51 
14999.30 
33952 .32 
25071 .64 
21913 .18 
19834.73 
12866.69 
8652.38 
4852.48 
3342.36 
85604.38 
71125 .22 
68338.59 
6595.79 
11975.59 
63883.67 
23443.99 
12527.40 
8876.34 
7405.17 
4204.21 
10134.24 
157175.46 
883310.98 
63658.44 
128799.69 
11220.17 
5195.16 
406998.99 
8636.83 
65377.99 
47911.01 
10409.80 
13300.20 
11596.13 
12883.18 
5065 .27 
88827.79 
TOTAL 
12632.40 
10454.40 
12196.80 
148104.00 
89298.00 
16988.40 
17424.00 
16117.20 
16988.40 
13068.00 
11325.60 
102801.60 
3484.80 
366339.60 
324957.60 
8276.40 
74487.60 
40075.20 
21780.00 
16117.20 
57934.80 
36154.80 
48351.60 
23086.80 
48787.20 
13068.00 
7405.20 
6969.60 
143312.40 
120661.20 
127630.80 
79714.80 
16988.40 
72309.60 
43124.40 
30056.40 
17424.00 
7405.20 
16988.40 
35719.20 
185130.00 
960498.00 
275733.15 
132215.80 
13503.60 
13939.20 
507474.00 
155286.61 
105415.20 
131115.60 
14374.80 
14374.80 
14374.80 
14374.80 
10454.40 
177289.20 
GROVE NUMBER GROVE TOTAL ACRES 
3 12.47 
3 12.47 
3 12.47 
3 12.47 
3 12.47 
45 2.57 
45 2.57 
45 2.57 
45 2.57 
45 2.57 
45 2.57 
45 2.57 
45 2.57 
71 39.20 
71 39.20 
71 39.20 
64 5.31 
64 5.31 
64 5.31 
64 5.31 
64 5.31 
64 5.31 
64 5.31 
64 5.31 
64 5.31 
64 5.31 
64 5.31 
64 5.31 
71 39.20 
71 39.20 
71 39.20 
71 39.20 
64 5.31 
64 5.31 
64 5.31 
64 5.31 
64 5.31 
71 39.20 
71 39.20 
71 39.20 
3 12.47 
36 30.97 
33 3.79 
36 30.97 
3 12.47 
3 12.47 
36 30.97 
36 30.97 
36 30.97 
36 30.97 
48 6.99 
48 6.99 
48 6.99 
48 6.99 
48 6.99 
36 30.97 
City of Tigard Urban l'orcstry Code ReYisions I Volume 11 I 407 
TLID 
2S103AC00202 
2S103AC00203 
2S103AC00204 
2S103AC00501 
2S103AC01100 
2S103AC01700 
2S103AC01701 
2S103AC01900 
2S103AC03900 
2S103AC04000 
2S103AC04100 
2S103AC04200 
2S103AC04300 
2S103AC05400 
2S103AC05600 
2S103AC05700 
2S103AC05800 
2S103AC06400 
2S103AC08100 
2S103AC09100 
2S103AD00810 
2S103AD00811 
2S103AD01000 
2S103AD06800 
2S103BB00400 
2S103BB00700 
2S103BB00800 
2S103BB03301 
2S103BB06300 
2S103BC02500 
2S103BC02600 
2S103BC03700 
2S103BC03800 
2S103BC04200 
2S103BC04300 
2S103BC04400 
2S103BC04500 
2S103BC04600 
2S103BC05700 
2S103BC05800 
2S103BC05900 
2S103BC07200 
2S103BC07400 
2S103BC07500 
2S103BC07600 
2S103BC08400 
2S103BC10300 
2S103BC10400 
2S103BC10600 
2S103BC10900 
2S103BD04000 
2S103BD04101 
2S103BD04200 
2S103BD04300 
2S103BD05900 
2S103BD06000 
IN TREE GROVE 
18580.24 
11551.29 
31189.02 
66612.49 
23285 .68 
49905 .19 
10259.97 
282.53 
3109 .25 
2970.71 
999.79 
2878.34 
3868.10 
1215.65 
2689 .80 
3265 .84 
1545.34 
24423 .14 
3936.28 
39457.30 
9919.13 
40226.18 
1395.92 
45432.36 
1225.02 
1694.81 
1933 .03 
199.77 
19154.37 
3723.73 
6511.12 
32977.49 
59156.96 
2766.88 
4379.11 
5671.08 
7513.15 
29719.82 
2590.42 
7026.91 
25561.81 
1078.75 
1383.41 
721.83 
1309.00 
3451.69 
32009.70 
49513 .73 
2043.23 
12058.47 
60853 .35 
3397.83 
3824.51 
9050.79 
1394.46 
1368.23 
TAXLOT SIZE (sq ft) 
OUTSIDE TREE GROVE 
4942.16 
209.91 
1916.58 
41416.31 
12433.52 
18484.01 
33300.03 
19319.47 
6473.95 
5741.29 
8147.81 
6269.26 
6586.30 
5753.95 
6457.80 
5010.56 
5859.86 
11731.66 
6953 .72 
11943.50 
2277.67 
4640.62 
9494.08 
9453.24 
7486.98 
10066.39 
8521.37 
34212.63 
84954.03 
11522.27 
8734.88 
46301.71 
19686.64 
6380.72 
7382 .09 
8703 .72 
9475 .25 
10790.98 
7863 .98 
8654.69 
1009 .79 
11553 .65 
11248.99 
11910.57 
13937.00 
2646.71 
8501 .10 
1015.87 
5361.97 
1445.13 
35414.25 
10541.37 
16213 .09 
8373 .21 
5139 .54 
5601 .37 
TOTAL 
23522.40 
11761.20 
33105 .60 
108028.80 
35719.20 
68389.20 
43560.00 
19602.00 
9583.20 
8712.00 
9147.60 
9147.60 
10454.40 
6969 .60 
9147.60 
8276.40 
7405 .20 
36154.80 
10890.00 
51400.80 
12196.80 
44866.80 
10890.00 
54885.60 
8712.00 
11761.20 
10454.40 
34412.40 
104108.40 
15246.00 
15246.00 
79279.20 
78843 .60 
9147.60 
11761.20 
14374.80 
16988.40 
40510.80 
10454.40 
15681.60 
26571.60 
12632.40 
12632.40 
12632.40 
15246.00 
6098.40 
40510.80 
50529.60 
7405.20 
13503 .60 
96267.60 
13939.20 
20037.60 
17424.00 
6534.00 
6969.60 
GROVE NUMBER GROVE TOTAL ACRES 
48 6.99 
48 6.99 
48 6.99 
48 6.99 
48 6.99 
56 6.69 
56 6.69 
56 6.69 
48 6.99 
48 6.99 
48 6.99 
48 6.99 
48 6.99 
48 6.99 
48 6.99 
48 6.99 
48 6.99 
48 6.99 
48 6.99 
56 6.69 
56 6.69 
56 6.69 
45 2.57 
56 6.69 
42 2.21 
42 2.21 
42 2.21 
42 2.21 
42 2.21 
51a 12 .84 
51a 12.84 
51a 12.84 
51a 12.84 
51a 12 .84 
51a 12 .84 
51a 12 .84 
51a 12 .84 
51a 12 .84 
51a 12 .84 
51a 12.84 
51a 12.84 
51a 12 .84 
51a 12 .84 
51a 12.84 
51a 12.84 
51a 12.84 
51a 12.84 
51a 12.84 
51a 12.84 
51a 12.84 
47 2.02 
47 2.02 
47 2.02 
47 2.02 
48 6.99 
48 6.99 
Cit~ of Tigard Urban h>restn· Code Re,· isions I \ 'olume I I I 40K 
TLID 
2S103BD06100 
2S103BD06200 
2S103BD08700 
2S103BD10500 
2S103BD10600 
2S103CA00102 
2S103CA00105 
2S103CA00106 
2S103CA00108 
2S103CA00109 
2S103CA00301 
2S103CA00302 
2S103CA00307 
2S103CA00309 
2S103CA00310 
2S103CA00311 
2S103CA02200 
2S103CA02300 
2S103CA02400 
2S103CA05100 
2S103CA05200 
2S103CB00900 
2S103CB03400 
2S103CB03500 
2S103CB03600 
2S103CB03700 
2S103CB03800 
2S103CB12400 
2S103CD01300 
2S103CD01400 
2S103CD01500 
2S103CD01600 
2S103CD05000 
2S103CD05100 
2S103CD05700 
2S103CD07200 
2S103CD07300 
2S103CD07600 
2S103CD07700 
2S103CD08600 
2S103DA01900 
2S103DA01901 
2S103DB00700 
2S103DB04600 
2S103DB04700 
2S103DB04800 
2S103DB04900 
2S103DB05000 
2S103DB06800 
2S103DB07201 
2S103DB07300 
2S103DB07400 
2S103DB07700 
2S103DB08400 
2S103DB11800 
2S103DB11900 
IN TREE GROVE 
1131.55 
101.24 
44190.62 
25533 .83 
1842.42 
1955.66 
15200.73 
13281.22 
4294.34 
4413.10 
7190.30 
8723 .75 
1179.38 
18253.19 
8195.16 
14238.88 
1298.85 
6383.80 
1126.79 
3121.80 
35658.97 
19086.80 
13066.00 
14940.72 
10625.13 
8660.33 
11373.46 
1757.54 
245.36 
3042.35 
2709.04 
1613.24 
1524.15 
3432.22 
63475.78 
26908.24 
1824.34 
1051.05 
473.67 
44299.34 
15663.31 
6777.52 
1142.02 
2054.42 
3593.75 
1152.99 
63475.53 
158.04 
752.54 
1915.31 
2572.12 
689.64 
60430.81 
1064.35 
111.07 
5837.55 
TAXLOT SIZE (sq ft) 
OUTSIDE TREE GROVE 
6273.65 
6432 .76 
27683 .38 
11056.57 
1642.38 
4142.74 
20954.07 
25051.58 
5724.46 
14317.70 
11104.90 
12620.65 
20165 .02 
1348.81 
9664.44 
3620.72 
14818.35 
9733.40 
14119.21 
5590.20 
10950.23 
64112.80 
15248.00 
9017.28 
10283.67 
17911.27 
16504.94 
12181.66 
11080.24 
6540.85 
7309.76 
6663.16 
5881.05 
5279.78 
11883.02 
7068.56 
6452.06 
11581.35 
9980.73 
6230.26 
10908.29 
14566.88 
9747.98 
9271.18 
6425.05 
8865.81 
10140.87 
9860.76 
10137.46 
8974.69 
7882.28 
10635.96 
19719.59 
15488.45 
2502.53 
1567.65 
TOTAL 
7405.20 
6534.00 
71874.00 
36590.40 
3484.80 
6098.40 
36154.80 
38332.80 
10018.80 
18730.80 
18295.20 
21344.40 
21344.40 
19602.00 
17859.60 
17859.60 
16117.20 
16117.20 
15246.00 
8712.00 
46609.20 
83199.60 
28314.00 
23958.00 
20908.80 
26571.60 
27878.40 
13939.20 
11325.60 
9583.20 
10018.80 
8276.40 
7405.20 
8712.00 
75358.80 
33976.80 
8276.40 
12632.40 
10454.40 
50529.60 
26571.60 
21344.40 
10890.00 
11325.60 
10018.80 
10018.80 
73616.40 
10018.80 
10890.00 
10890.00 
10454.40 
11325.60 
80150.40 
16552.80 
2613.60 
7405.20 
GROVE NUMBER 
48 
48 
48 
47 
48 
60 
60 
60 
60 
60 
49 
49 
49 
49 
49 
49 
49 
49 
49 
60 
60 
51 a 
51 a 
51 a 
51 a 
51 a 
51 a 
51 a 
60 
60 
60 
60 
60 
60 
60 
60 
60 
60 
60 
60 
56 
56 
56 a 
56 a 
56 a 
56 a 
56 a 
56 a 
56 a 
56 
56 
56 
56 
56 
56 a 
56 
City of Tigard Urban Forestry Code Revisions I Volume I I I 409 
GROVE TOTAL ACRES 
6.99 
6.99 
6.99 
2.02 
6.99 
5.25 
5.25 
5.25 
5.25 
5.25 
1.54 
1.54 
1.54 
1.54 
1.54 
1.54 
1.54 
1.54 
1.54 
5.25 
5.25 
12.84 
12.84 
12.84 
12.84 
12.84 
12.84 
12.84 
5.25 
5.25 
5.25 
5.25 
5.25 
5.25 
5.25 
5.25 
5.25 
5.25 
5.25 
5.25 
6.69 
6.69 
2.83 
2.83 
2.83 
2.83 
2.83 
2.83 
2.83 
6.69 
6.69 
6.69 
6.69 
6.69 
2.83 
6.69 
TLID 
2S103DB12100 
2Sl03DC00100 
2S103DC00200 
2S103DC00300 
2S103DC00400 
2S103DC00824 
2S103DC01000 
2S103DC01100 
2S103DC01103 
2S103DC01104 
2S103DC02700 
2S103DC06000 
2S103DC06100 
2S103DC06200 
2S103DC06300 
2S1040001500 
2S1040001600 
2S104AA00102 
2S104AA00105 
2S104AA00108 
2S104AA00109 
2S104AA04600 
2S104AA11000 
2S104AA11100 
2S104AA11500 
2S104AA11600 
2S104AA11700 
2S104AA11800 
2S104AA90000 
2S104AB05700 
2S104AB05800 
2S104AB06300 
2S104AB09200 
2S104AB12500 
2S104AC01701 
2Sl04AC08500 
2S104AC10800 
2S104AC10900 
2S104AC13300 
2S104AC13400 
2S104AD03100 
2S104AD03301 
2S104AD03400 
2S104AD03401 
2S104AD03501 
2S104AD03700 
2S104AD03800 
2S104AD04100 
2S104AD04500 
2S104AD04501 
2S104BB14400 
2S104BD07200 
2S104BD07300 
2S104CA00100 
2S104CA00200 
2S104CA00300 
IN TREE GROVE 
706.53 
6142.35 
5524.72 
7386.28 
7345.34 
295.22 
4522.32 
44307.96 
6981.27 
7835.44 
577.14 
9950.51 
4871.60 
4451.75 
410.23 
582530.12 
580517.90 
79120.60 
1355.47 
100.29 
76 .13 
50628.24 
538.37 
1143.42 
1301.62 
4403.94 
2911.67 
1178.49 
389.38 
4339.76 
2487.40 
537.08 
401.04 
26138.93 
48.91 
94.55 
11461.49 
48708.67 
2562.57 
64358.04 
7238.68 
7790.49 
7122.92 
19933.34 
40750.28 
3483.05 
57300.61 
47932 .90 
1666.21 
19510.62 
869.51 
74244.43 
27259.43 
4210.26 
2993.40 
3497.94 
TAXLOT SIZE (sq ft) 
OUTSIDE TREE GROVE 
600.27 
16944.45 
17126.48 
12215.72 
11385.46 
8852.38 
138354.48 
154325.64 
4344.33 
2618.96 
6392.46 
23590.69 
12988.00 
23426.65 
24854.57 
156247.48 
14947.30 
37620.20 
4742 .93 
2077.71 
2101.87 
144412 .80 
6957.22 
6349 .99 
6306.12 
3563 .65 
4582.52 
6314.18 
93349.22 
9163.84 
10580.60 
12530.92 
7004.16 
11322.67 
11276.69 
8181.85 
29484.91 
43638.53 
18346.23 
26682.36 
39806.12 
35333 .91 
52118.68 
60217 .06 
33301 .72 
25702 .15 
23285 .39 
79262.30 
72821 .39 
100279.38 
3486.49 
9390.77 
3232.57 
5372 .94 
7025.40 
6520.86 
TOTAL 
1306.80 
23086.80 
22651.20 
19602.00 
18730.80 
9147.60 
142876.80 
198633.60 
11325.60 
10454.40 
6969 .60 
33541 .20 
17859.60 
27878.40 
25264.80 
738777.60 
595465.20 
116740.80 
6098.40 
2178.00 
2178.00 
195041.03 
7495.59 
7493.41 
7607.74 
7967.59 
7494.19 
7492 .67 
93738.60 
13503.60 
13068.00 
13068.00 
7405.20 
37461 .60 
11325.60 
8276.40 
40946.40 
92347.20 
20908.80 
91040.40 
47044.80 
43124.40 
59241.60 
80150.40 
74052.00 
29185.20 
80586.00 
127195.20 
74487.60 
119790.00 
4356.00 
83635.20 
30492.00 
9583.20 
10018.80 
10018.80 
GROVE NUMBER 
56 
56 a 
56 a 
56 a 
56 a 
63 
63 
63 
63 
63 
63 
56 a 
56 a 
56 a 
56 a 
55 
57 
37 
37 
37 
37 
42 
37 
37 
37 
37 
37 
37 
42 
37 
37 
37 
37 
37 
51 
37 
46 
46 
46 
46 
51 
51 
51 
51 
51 
51 
51 
51 a 
42 
42 
31 
57 
57 
57 
57 
57 
City o f Tigard Urban l'orcstn· Code Rc,·isions I \'olumc II I 4lll 
GROVE TOTAL ACRES 
6.69 
2.83 
2.83 
2.83 
2.83 
1.48 
1.48 
1.48 
1.48 
1.48 
1.48 
2.83 
2.83 
2.83 
2.83 
15.71 
20.89 
2.90 
2.90 
2.90 
2.90 
2.21 
2.90 
2.90 
2.90 
2.90 
2.90 
2.90 
2.21 
2.90 
2.90 
2.90 
2.90 
2.90 
5.91 
2.90 
2.94 
2.94 
2.94 
2.94 
5.91 
5.91 
5.91 
5.91 
5.91 
5.91 
5.91 
12.84 
2.21 
2.21 
3.68 
20.89 
20.89 
20.89 
20.89 
20.89 
TLID 
2S104CA00400 
2S104CA00500 
2S104CA00600 
2S104CA00700 
2S104CA00800 
2S104CA00900 
2S104CA01000 
2S104CA01100 
2S104CA01800 
2S104CA06900 
2S104CA07000 
2S104CB00100 
2S104CB00600 
2S104CB00700 
2S104CB00800 
2S104CB00900 
2S104CB01000 
2S104CB01100 
2S104CB01200 
2S104CB01300 
2S104CB01400 
2S104CB01700 
2S104CB01800 
2S104CB01900 
2S104CB02000 
2S104CB03500 
2S104CB03600 
2S104CB03700 
2S104CB03800 
2S104CB03900 
2S104CB04000 
2S104CB04100 
2S104CB04200 
2S104CB04300 
2S104CB04400 
2S104CB04500 
2S104CB07400 
2S104CB07700 
2S104CB07800 
2S104CC04500 
2S104CC04600 
2S104CC04700 
2S104CC04800 
2S104CC04900 
2S104CC05000 
2S104CC05100 
2S104CC05200 
2S104CC05300 
2S104CC05400 
2S104CC05500 
2S104CC05600 
2S104CC06300 
2S104CC06400 
2S104CC06500 
2S104CC06600 
2S104CC06700 
IN TREE GROVE 
3412.82 
2321.78 
3769.84 
4616.85 
4926.83 
4566.47 
3752.29 
1565.24 
9983.30 
520.41 
2395.63 
264.70 
878.68 
1657.80 
1711.86 
1000.10 
2928.24 
4756.14 
2236.77 
1818.67 
1304.50 
2174.88 
3871.67 
3093.79 
6637.75 
221.74 
1924.15 
3181.59 
2797.03 
1523.15 
1370.60 
1149.92 
2981.66 
1709.81 
5029.35 
8791.32 
6879.39 
270.14 
44709.88 
504.23 
3311.00 
4024.29 
2822.91 
4660.26 
7116.21 
3835.81 
4058.30 
4279.89 
6085.36 
5611.76 
38043.16 
5200.48 
1665.95 
973.71 
1654.95 
2209.75 
TAXLOT SIZE (sq ft) 
OUTSIDE TREE GROVE 
6605.98 
7697.02 
6248.96 
6708.75 
5527.57 
5016.73 
5395.31 
7146.76 
4827.10 
8627.19 
9365 .57 
11932.10 
10446.92 
10539.00 
10484.94 
11196.70 
9268.56 
7440.66 
9960.03 
8635.73 
8714.30 
11764.32 
10503.13 
13023.41 
8608.25 
11103.86 
10272.65 
9015.21 
9399.77 
10673.65 
10826.20 
11046.88 
10521.94 
12229.39 
10216.65 
9503.88 
3139.41 
67247.86 
10611.32 
12128.17 
11499.40 
11221.71 
15907.89 
14070.54 
7694.19 
10103.39 
9445.30 
7481.31 
8725.04 
8763.04 
2467.64 
13094.72 
8788.45 
10351.89 
9235.05 
8244.65 
TOTAL 
10018.80 
10018.80 
10018.80 
11325.60 
10454.40 
9583.20 
9147.60 
8712.00 
14810.40 
9147.60 
11761.20 
12196.80 
11325.60 
12196.80 
12196.80 
12196.80 
12196.80 
12196.80 
12196.80 
10454.40 
10018.80 
13939.20 
14374.80 
16117.20 
15246.00 
11325.60 
12196.80 
12196.80 
12196.80 
12196.80 
12196.80 
12196.80 
13503.60 
13939.20 
15246.00 
18295.20 
10018.80 
67518.00 
55321.20 
12632.40 
14810.40 
15246.00 
18730.80 
18730.80 
14810.40 
13939.20 
13503.60 
11761.20 
14810.40 
14374.80 
40510.80 
18295.20 
10454.40 
11325.60 
10890.00 
10454.40 
GROVE NUMBER GROVE TOTAL ACRES 
57 20.89 
57 20.89 
57 20.89 
57 20.89 
57 20.89 
57 20.89 
57 20.89 
57 20.89 
57 20.89 
59 13.18 
59 13.18 
55 15.71 
55 15.71 
55 15.71 
55 15.71 
55 15.71 
55 15.71 
55 15.71 
55 15.71 
55 15.71 
55 15.71 
55 15.71 
55 15.71 
55 15.71 
55 15.71 
57 20.89 
57 20.89 
57 20.89 
57 20.89 
57 20.89 
57 20.89 
57 20.89 
57 20.89 
57 20.89 
57 20.89 
57 20.89 
55 15.71 
55 15.71 
55 15.71 
57 20.89 
57 20.89 
57 20.89 
57 20.89 
57 20.89 
57 20.89 
57 20.89 
57 20.89 
57 20.89 
57 20.89 
57 20.89 
57 20.89 
55 15.71 
55 15.71 
55 15.71 
55 15 .71 
55 15 .71 
City of Tigard Urban Forestry Code RcYisions I Volume II I 411 
TLID 
2S104CC06800 
2S104CC06900 
2S104CC07000 
2S104CC07100 
2S104CC07200 
2S104CC07300 
2S104CC07400 
2S104CC07500 
2S104CC07600 
2S104CC07700 
2S104CC07800 
2S104CC07900 
2S104CC08000 
2S104CC08100 
2S104CC08200 
2S104CC08400 
2S104CD02000 
2S104CD02100 
2S104CD02200 
2S104CD02300 
2S104CD02400 
2S104CD02500 
2S104CD02600 
2S104CD02700 
2S104CD02800 
2S104CD02900 
2S104CD03000 
2S104CD03100 
2S104CD03200 
2S104CD03300 
2S104CD03400 
2S104CD03500 
2S104CD03600 
2S104CD03700 
2S104CD03800 
2S104CD03900 
2S104CD04000 
2S104CD04100 
2S104CD04200 
2S104CD04300 
2S104CD04400 
2S104CD04500 
2S104CD04600 
2S104CD04700 
2S104CD07400 
2S104CD07500 
2S104CD07600 
2S104CD11500 
2S104CD11600 
2S104DA01000 
2S104DA01300 
2S104DA03700 
2S104DA04000 
2S104DA04100 
2S104DA14600 
2S104DA15500 
IN TREE GROVE 
852.60 
703.34 
870.83 
157.44 
1515 .41 
7709 .36 
7580.60 
6274.67 
5868.48 
4604.48 
3256.80 
2870.83 
4437.10 
5281.71 
6391.16 
1522.09 
2103.60 
5196.07 
5406.10 
4042 .10 
4229.82 
4461.44 
4384.02 
4330.95 
3284.74 
3635.79 
5409.89 
5140.18 
5325.25 
8175 .13 
10776.51 
20699.17 
14278.17 
11459.82 
10170.37 
11953.17 
10355.23 
11289.91 
10269.67 
7974.31 
7327.87 
6265.84 
5484.81 
2745.86 
4104.46 
3431.53 
173 .73 
1787.98 
2921.04 
42350.77 
90921 .61 
352.42 
1681 .03 
0.18 
6715 .25 
113662 .20 
TAXLOT SIZE (sq ft) 
OUTSIDE TREE GROVE 
9601.80 
9751.06 
9583.57 
12039.36 
10681.39 
8407.84 
8536.60 
8535.73 
7635.12 
5849.92 
6326.40 
6276.77 
6017.30 
6043.89 
7112.44 
15466.31 
8350.80 
5258.33 
5048.30 
7719 .10 
5788.98 
5992.96 
6505.98 
6559.05 
8476.46 
7689.81 
5915.71 
6185.42 
6435.95 
5764.07 
7083 .09 
9357.23 
8808.63 
8142 .18 
7689 .23 
7213 .23 
7939 .97 
8312 .09 
9332.33 
10320.89 
9224.93 
8544.56 
8889.99 
11193 .34 
15061 .94 
17912 .87 
19428.27 
3874.82 
9711.36 
84844.43 
454885.19 
8795.18 
10515.77 
8711.82 
47299.15 
69725.40 
TOTAL 
10454.40 
10454.40 
10454.40 
12196.80 
12196.80 
16117.20 
16117.20 
14810.40 
13503.60 
10454.40 
9583.20 
9147.60 
10454.40 
11325 .60 
13503.60 
16988.40 
10454.40 
10454.40 
10454.40 
11761 .20 
10018.80 
10454.40 
10890.00 
10890.00 
11761 .20 
11325.60 
11325.60 
11325.60 
11761.20 
13939.20 
17859 .60 
30056.40 
23086.80 
19602.00 
17859.60 
19166.40 
18295.20 
19602.00 
19602.00 
18295.20 
16552.80 
14810.40 
14374.80 
13939.20 
19166.40 
21344.40 
19602.00 
5662.80 
12632.40 
127195.20 
545806.80 
9147.60 
12196.80 
8712.00 
54014.40 
183387.60 
GROVE NUMBER GROVE TOTAL ACRES 
55 15.71 
55 15.71 
55 15.71 
55 15.71 
55 15.71 
57 20 .89 
57 20 .89 
57 20 .89 
57 20.89 
57 20.89 
57 20 .89 
57 20.89 
57 20.89 
57 20.89 
57 20.89 
57 20.89 
59 13.18 
59 13.18 
59 13.18 
59 13.18 
59 13.18 
59 13.18 
59 13.18 
59 13.18 
59 13.18 
59 13 .18 
59 13.18 
59 13 .18 
59 13 .18 
59 13.18 
59 13.18 
59 13.18 
59 13.18 
59 13.18 
59 13 .18 
59 13 .18 
59 13 .18 
59 13.18 
59 13.18 
59 13.18 
59 13.18 
59 13.18 
59 13.18 
59 13.18 
65 13.02 
65 13 .02 
65 13 .02 
57 20.89 
57 20.89 
51a 12.84 
51a 12.84 
52 3.27 
52 3.27 
52 3.27 
51a 12.84 
51 5.91 
City ofTigarJ Urban J;orcs try Code RcYisions I \ 'olume II I 412 
TLID 
2S104DA16400 
2S104DB00100 
2S104DB04900 
2S104DB05200 
2S104DB05300 
2S104DB06000 
2S104DB06200 
2S104DB06300 
2S104DB06400 
2S104DB06700 
2S104DC01000 
2S104DC01100 
2S104DC01200 
2S104DC02000 
2S104DC02100 
2S104DC02200 
2S104DC02300 
2S104DC02400 
2S104DC02500 
2S104DC02600 
2S104DC02700 
2S104DC02800 
2S104DC02900 
2S104DC05200 
2S104DC05901 
2S104DC07100 
2S104DC07200 
2S104DC07300 
2S104DC07400 
2S104DC07800 
2S104DC08100 
2S104DC08200 
2S104DC08400 
2S104DC08500 
2S104DC08600 
2S104DC08700 
2S104DC08800 
2S104DC09800 
2S104DD03000 
2S104DD06600 
2S104DD07100 
2S104DD09600 
2S105CD00100 
2S105DA00400 
2S105DA00500 
2S105DB00100 
2S105DB00400 
2S105DB00500 
2S105DB06100 
2S105DB06200 
2S105DC00100 
2S105DC00101 
2S105DC00201 
2S105DC00400 
2S105DD00100 
2S105DD00200 
IN TREE GROVE 
140436.57 
1073.99 
209092.47 
9894.28 
202.09 
7047.41 
9874.66 
2524.30 
4321.14 
8130.68 
3106.05 
2930.90 
10158.23 
1447.43 
3116.97 
3066.81 
3209.26 
3194.47 
3336.88 
3139.39 
3465.23 
4801.69 
2109.95 
80683.57 
83159.47 
3240.47 
2697.74 
2114.73 
509.77 
61939.83 
4325.40 
4678.93 
2845.35 
3731.41 
3295 .98 
2040.95 
2671 .67 
225135 .35 
20939.45 
211534.88 
0.23 
80124.85 
123833.48 
45567.70 
45318.64 
255542.25 
361414.39 
45631.62 
37531.42 
891.67 
5910.89 
181.94 
448674.49 
13432.38 
97848.98 
20151.37 
TAXLOT SIZE (sq ft) 
OUTSIDE TREE GROVE 
65166.63 
8509.21 
6529 .53 
43248.92 
56861.51 
2535.79 
7113 .74 
5752.10 
4826.46 
14084.92 
6041.55 
4909.90 
7701.37 
8135.77 
6901.83 
6951.99 
6809.54 
6824.33 
7117.52 
8186.21 
8295.97 
8701.91 
8344.45 
338.03 
3960.53 
7213.93 
6885.46 
7904.07 
8202.23 
6449.37 
6564.60 
6646.67 
7609.05 
7158.59 
7594.02 
7977.85 
11703.13 
23156.65 
21749.35 
88157.92 
13938.97 
31388.75 
16865.32 
9753.50 
14358.56 
21063.75 
119052.41 
77207.58 
21710.18 
15225.53 
133481.11 
41200.06 
80579.51 
27078.42 
8437.42 
321.83 
TOTAL 
205603.20 
9583.20 
215622.00 
53143 .20 
57063.60 
9583.20 
16988.40 
8276.40 
9147.60 
22215 .60 
9147.60 
7840.80 
17859.60 
9583.20 
10018.80 
10018.80 
10018.80 
10018.80 
10454.40 
11325.60 
11761.20 
13503.60 
10454.40 
81021.60 
87120.00 
10454.40 
9583.20 
10018.80 
8712.00 
68389.20 
10890.00 
11325.60 
10454.40 
10890.00 
10890.00 
10018.80 
14374.80 
248292.00 
42688.80 
299692.80 
13939.20 
111513.60 
140698.80 
55321.20 
59677.20 
276606.00 
480466.80 
122839.20 
59241.60 
16117.20 
139392.00 
41382 .00 
529254.00 
40510.80 
106286.40 
20473.20 
GROVE NUMBER GROVE TOTAL ACRES 
52 3.27 
59 13.18 
59 13.18 
59 13.18 
46 2.94 
59 13.18 
59 13.18 
59 13.18 
59 13.18 
59 13 .18 
65 13.02 
65 13.02 
65 13.02 
59 13.18 
59 13.18 
59 13.18 
59 13.18 
59 13.18 
59 13.18 
59 13.18 
59 13.18 
59 13.18 
59 13.18 
59 13.18 
65 13.02 
65 13.02 
65 13 .02 
65 13 .02 
65 13 .02 
65 13.02 
65 13.02 
65 13.02 
65 13.02 
65 13.02 
65 13.02 
65 13.02 
65 13.02 
65 13.02 
75 24.34 
75 24.34 
75 24.34 
75 24.34 
67 54.40 
67 54.40 
67 54.40 
67 54.40 
67 54.40 
67 54.40 
67 54.40 
67 54.40 
67 54.40 
67 54.40 
67 54.40 
67 54.40 
67 54.40 
67 54.40 
C:ity of Tigard Urban Forestry Code Revisions I Volume II I 413 
TLID 
2S105DD00300 
2S105DD00600 
2S105DD01100 
2S105DD01800 
2S105DD01900 
2S105DD02100 
2S105DD02101 
2S105DD02200 
2S108AB04600 
2S108AB04700 
2S108AB04800 
2S109AA00200 
2S109AA00300 
2S109AA00400 
2S109AA00500 
2S109AA00700 
2S109AA00800 
2S109AA00900 
2S109AA01000 
2S109AA01100 
2S109AA01201 
2S109AA03800 
2S109AA04800 
2S109AA04900 
2S109AA05000 
2S109AA05800 
2S109AA05900 
2S109AA06200 
2S109AA06300 
2S109AA06400 
2S109AB02600 
2S109AB05600 
2S109AB11400 
2S109AD00600 
2S109AD00700 
2S109AD08100 
2S109BA00700 
2S109BA00800 
2S109BA00900 
2S110AA01700 
2S110AA90000 
2S110AC00100 
2S110AC00200 
2S110AC00400 
2S110AC00500 
2S110AC00900 
2S110AD01200 
2S110AD08690 
2S110AD08700 
2S110AD08702 
2S110AD08800 
2S110AD08802 
2S110AD08805 
2S110AD08806 
2S110AD09600 
2S110AD09800 
IN TREE GROVE 
103859.73 
12327 .14 
338358.79 
120682 .60 
138741 .56 
15206.88 
5632 .52 
75672.12 
6036.87 
3544.79 
3838.07 
1080.08 
249231.54 
11522.82 
6986.08 
49724.44 
62790.50 
74094.66 
22230.32 
18356.82 
79011.87 
17656.26 
1289.44 
12184.16 
10835.37 
3682.48 
1018 .15 
4358.68 
31380.47 
198.83 
0.03 
135625.12 
11932.51 
28397.62 
19410.28 
1857.46 
1025.49 
3920.71 
357.48 
8589.29 
79522.16 
34172.69 
117461.66 
83837.13 
125168.93 
270001.44 
1163.09 
608.59 
150.87 
4503.10 
17911.27 
522 .15 
10605.51 
1646.03 
1263.03 
2899.86 
TAXLOT SIZE (sq ft) 
OUTSIDE TREE GROVE 
7653.87 
28619.26 
508012.01 
57042.20 
-39860.36 
3088.32 
44461.48 
11447.88 
6159.93 
7780.81 
10101.13 
35945 .92 
45669.66 
25938.78 
25683 .92 
22585 .16 
57435 .10 
64426.14 
48772.48 
27816.78 
8979 .33 
6737.34 
6551 .36 
9595 .84 
16171.83 
7207.52 
18583 .85 
5660.12 
418.33 
1107.97 
9147.57 
15092.48 
18995 .09 
20389.58 
24149.72 
5983.34 
8557.71 
6969 .29 
10532.52 
144741.91 
427080.64 
239.71 
53293 .54 
125250.87 
179315 .47 
87190.56 
1562.64 
8539.01 
129222.33 
31216.10 
8660.33 
24307.05 
3769.29 
77633 .17 
31415 .50 
53329.49 
TOTAL 
111513 .60 
40946.40 
846370.80 
177724.80 
98881.20 
18295 .20 
50094.00 
87120.00 
12196.80 
11325.60 
13939.20 
37026.00 
294901.20 
37461.60 
32670.00 
72309.60 
120225.60 
138520.80 
71002.80 
46173 .60 
87991.20 
24393 .60 
7840.80 
21780.00 
27007.20 
10890.00 
19602.00 
10018.80 
31798.80 
1306.80 
9147.60 
150717.60 
30927.60 
48787.20 
43560.00 
7840.80 
9583 .20 
10890.00 
10890.00 
153331.20 
506602.80 
34412.40 
170755 .20 
209088.00 
304484.40 
357192 .00 
2725.73 
9147.60 
129373 .20 
35719.20 
26571.60 
24829.20 
14374.80 
79279.20 
32678.53 
56229.34 
GROVE NUMBER GROVE TOTAL ACRES 
67 54.40 
67 54.40 
67 54.40 
67 54.40 
67 54.40 
67 54.40 
67 54.40 
67 54.40 
67 54.40 
67 54.40 
67 54.40 
75 24.34 
75 24 .34 
75 24.34 
75 24.34 
75 24.34 
75 24.34 
75 24.34 
75 24.34 
75 24.34 
75 24.34 
75 24.34 
75 24.34 
75 24.34 
75 24.34 
75 24 .34 
75 24.34 
75 24 .34 
75 24 .34 
75 24 .34 
65 13.02 
65 13.02 
75 24 .34 
75 24 .34 
75 24.34 
75 24.34 
65 13.02 
65 13.02 
65 13.02 
86 18.25 
73 1.97 
86 18.25 
86 18.25 
86 18.25 
86 18.25 
86 18.25 
73 1.97 
83 3.46 
86 18.25 
86 18.25 
86 18.25 
86 18.25 
86 18.25 
86a 4.12 
83 3.46 
86a 4.12 
City of Tigard Urban l'o rc:s try Code Rc:,·isions I \ 'olumc: II I 41-l 
TLID 
2S110AD90000 
2S110DA00300 
2S110DA00400 
2S110DA10000 
2S110DB00200 
2S110DB01400 
2S110DB01500 
2S111AA00300 
2S111AA00500 
2S111AA00600 
2S111AA00700 
25 111AA00800 
2S111AA01400 
25 111AA06800 
25111AA06900 
25111AA07000 
25111AA07500 
2S111AB00401 
2S111AB00402 
2S111AB00403 
2S111AB00501 
2S111AB00700 
2S111AB00800 
2S111AB00900 
2S111AB01000 
2S111AB01201 
2S111AB01300 
2S111AB01400 
2S111AB01500 
2S111AB01700 
25111AB02100 
2S111AB02300 
2S111AC00400 
25111AC00500 
25111AD03400 
25111AD05500 
25111AD05600 
2S111AD05700 
2S111AD05800 
2S111AD06201 
2S111AD06202 
2S111AD07100 
2S111AD17300 
2S111AD21000 
2S111BB02300 
2S111BC02600 
2S111BC02603 
2S111BC02900 
2S111BC03001 
2S111CB01301 
2S111CB01311 
2S111CB01390 
2S111CD00300 
2S111CD02600 
25111CD02900 
2S111CD03000 
IN TREE GROVE 
77855.44 
53535.99 
33292.39 
9859.00 
14613.95 
3573.32 
92408.35 
9699.73 
1156.96 
2347.05 
74709.94 
8512 .06 
89064.25 
1064.94 
1561.15 
146.61 
25146.99 
15289.08 
15113.26 
2739.38 
3835.06 
6544.46 
4827.19 
10804.45 
13854.06 
6255.24 
8762.02 
3575.24 
8825.38 
1141.45 
3161.83 
6746.04 
572.85 
920.65 
6060.14 
51.52 
6770.29 
12844.69 
3904.45 
3837.84 
2250.23 
50646.86 
2038.40 
51092 .63 
716.86 
9380.22 
112390.39 
1072.53 
3554.79 
3668.12 
1756.62 
66.19 
19129.46 
22821.02 
607.10 
2102.30 
TAXLOT SIZE (sq ft) 
OUTSIDE TREE GROVE 
141367.31 
19644.81 
36839.21 
159.80 
496780.45 
128849.08 
5166.05 
23841.47 
12782.24 
12463.35 
55534.46 
121732.34 
175344.95 
7647.06 
7150.85 
8129.79 
2295.81 
1263.72 
2746.34 
15120.22 
8361.74 
5652.34 
7369.61 
956.75 
8797.14 
16395.96 
10404.38 
11670.76 
10341.02 
15411.35 
12084.17 
8499.96 
9010.35 
8226.95 
7007.86 
12145.28 
10653.71 
12420.11 
8727.95 
6180.96 
6897.37 
10337.14 
44570.80 
17296.57 
10173.14 
80353 .38 
20903 .21 
18093.87 
17354.01 
11577.88 
13053.78 
2983.01 
101531.74 
141835.78 
5055 .70 
9223.30 
TOTAL 
219222 .75 
73180.80 
70131.60 
10018.80 
511394.40 
132422.40 
97574.40 
33541.20 
13939.20 
14810.40 
130244.40 
130244.40 
264409.20 
8712.00 
8712.00 
8276.40 
27442 .80 
16552.80 
17859.60 
17859.60 
12196.80 
12196.80 
12196.80 
11761.20 
22651 .20 
22651.20 
19166.40 
15246.00 
19166.40 
16552.80 
15246.00 
15246.00 
9583.20 
9147.60 
13068.00 
12196.80 
17424.00 
25264.80 
12632.40 
10018.80 
9147.60 
60984.00 
46609.20 
68389.20 
10890.00 
89733.60 
133293.60 
19166.40 
20908.80 
15246.00 
14810.40 
3049.20 
120661.20 
164656.80 
5662.80 
11325.60 
GROVE NUMBER GROVE TOTAL ACRES 
86a 4.12 
86a 4.12 
86a 4.12 
86a 4.12 
86 18.25 
86 18.25 
86 18.25 
69 2.25 
69 2.25 
69 2.25 
69 2.25 
69 2.25 
77 2.86 
77 2.86 
77 2.86 
77 2.86 
77 2.86 
68 2.76 
68 2.76 
68 2.76 
68 2.76 
68 2.76 
68 2.76 
68 2.76 
68 2.76 
68 2.76 
68 2.76 
68 2.76 
68 2.76 
68 2.76 
68 2.76 
68 2.76 
77 2.86 
77 2.86 
77 2.86 
81 3.08 
81 3.08 
81 3.08 
81 3.08 
81 3.08 
81 3.08 
81 3.08 
81 3.08 
81 3.08 
73 1.97 
83 3.46 
83 3.46 
73 1.97 
73 1.97 
83 3.46 
83 3.46 
83 3.46 
89 1.21 
89 1.21 
89 1.21 
89 1.21 
City of Tigard Urban Forestry Code Revisions I Volume 11 I 415 
TLID 
2S111CD03100 
2S111CD03400 
2S111CD03500 
2S111CD03600 
2S111CD03700 
2S111CD03800 
2S111CD03900 
2S112BA03400 
2S112BA04700 
2S112BA05602 
2S112BA06000 
2S112BA06100 
2S112BA06200 
2S112BA06400 
2S112BA11900 
2S112BA90000 
2S112BB04000 
2S112BB04100 
2S112BB04400 
2S112BB04401 
2S112BB11200 
2S112BB11300 
2S112BB12900 
2S112BD00400 
2S112BD00900 
2S112BD01000 
2S112BD01100 
2S112BD03900 
2S 112 B 090000 
2S112CA00200 
2S112CA00300 
2S112CA01400 
2S112CA04000 
2S112CA11900 
2S112CA13400 
2S112CA13600 
2S112CA13700 
2S112CA13800 
2S112CA13900 
2S112CB01300 
2S112CB01500 
2S112CB01600 
2S112CB01700 
2S112CB01800 
2S112CB01900 
2S112CB02000 
2S112CB02100 
2S112CC00102 
2S112CC00104 
2S112CC00106 
2S112CC00107 
2S112CC00111 
2S112CC00112 
2S112CC02700 
2S112CC02800 
2S112CC02900 
IN TREE GROVE 
2295 .24 
489 .07 
1630.95 
1309 .73 
688 .26 
945.99 
S41.63 
35404.27 
9462 .83 
23693.84 
18196.24 
5339 .98 
13339.43 
10320.12 
86320.17 
25688.85 
7443.30 
81557.49 
1282.92 
3064.53 
60441.39 
1581 .95 
53174.54 
2610.35 
10322 .29 
68166.33 
8978.37 
915.67 
1176.48 
3590.37 
47435.47 
44130.41 
17222 .29 
48159.70 
51815.29 
811.89 
5276.09 
7779.02 
21.68 
4254.26 
1017.03 
4408.33 
3161.19 
1582.82 
695 .82 
919.66 
172.77 
675 .82 
4912.86 
5325.11 
5703 .32 
4109.62 
4558.68 
444.59 
2904.98 
569.21 
TAXLOT SIZE (sq ft) 
OUTSIDE TREE GROVE 
7287.96 
3866.93 
5774.25 
6095.47 
3667.74 
3410.01 
3814.37 
36034.13 
13188.37 
5491.36 
4890.56 
322.82 
229289.77 
193105.08 
31291.83 
256319.45 
66173.10 
51736.11 
10042.68 
7825.47 
4463.01 
5823.25 
16521 .46 
162046.45 
4052.51 
4143.27 
31968.03 
1262.33 
96813.56 
23852.43 
20953 .73 
11190.79 
23724.11 
10210.70 
9168.71 
14434.11 
2564.71 
2239 .78 
6076.72 
537.34 
4645 .77 
4303.67 
4244.01 
4079.98 
4966.98 
4743 .14 
5490.03 
4551 .38 
314.34 
337.69 
2137.48 
681.98 
232 .92 
5653.81 
5807.02 
8578.39 
TOTAL 
9583.20 
4356.00 
7405.20 
7405.20 
4356.00 
4356.00 
4356.00 
71438.40 
22651.20 
29185.20 
23086.80 
5662.80 
242629.20 
203425.20 
117612.00 
282008.30 
73616.40 
133293 .60 
11325 .60 
10890.00 
64904.40 
7405.20 
69696.00 
164656.80 
14374.80 
72309.60 
40946.40 
2178.00 
97990.04 
27442.80 
68389.20 
55321.20 
40946.40 
58370.40 
60984.00 
15246.00 
7840.80 
10018.80 
6098.40 
4791 .60 
5662 .80 
8712 .00 
7405.20 
5662.80 
5662.80 
5662.80 
5662.80 
5227.20 
5227.20 
5662.80 
7840.80 
4791 .60 
4791 .60 
6098.40 
8712.00 
9147.60 
GROVE NUMBER GROVE TOTAL ACRES 
89 1.21 
89 1.21 
89 1.21 
89 1.21 
89 1.21 
89 1.21 
89 1.21 
71 39.20 
74 3.89 
71 39.20 
71 39.20 
71 39.20 
71 39.20 
71 39.20 
71 39.20 
71 39.20 
74 3.89 
74 3.89 
74 3.89 
74 3.89 
74 3.89 
74 3.89 
71 39.20 
93 21 .15 
79 2.08 
79 2.08 
79 2.08 
79 2.08 
79 2.08 
93 21.15 
93 21.15 
93 21.15 
90 2.53 
93 21.15 
93 21.15 
90 2.53 
90 2.53 
90 2.53 
90 2.53 
90 2.53 
90 2.53 
90 2.53 
90 2.53 
90 2.53 
90 2.53 
90 2.53 
90 2.53 
90 2.53 
90 2.53 
90 2.53 
90 2.53 
90 2.53 
90 2.53 
90 2.53 
90 2.53 
90 2.53 
CitY of Tigaru Urban l:ore> Lry Couc RcYi>ion> I \ 'olumc II I 41(, 
TLID 
25112CC03000 
25112CC03100 
25112CC03200 
25112CC03300 
25112CC03400 
25112CC03500 
25112CC03601 
25112CC03800 
25112CC03900 
25112CC04000 
2S112CC04101 
25112CC04200 
25112CC06600 
25112CC06800 
25112CC19500 
25112CC19900 
25112CC20900 
25112CD00300 
25112CD00400 
25112CD00800 
25112CD00900 
2S112CD07300 
25112CD07600 
25112CD07700 
25112CD09100 
2S112CD09200 
25112DB00600 
2S112DB00700 
2S112DB00800 
2S112DC01400 
2S112DC01500 
2S112DC01601 
2S112DD00701 
2S112DD01100 
2S113AB00800 
251138000300 
2S113B000600 
25113BA00100 
2S113BA00400 
2S113BA00500 
2S113BA00600 
2S114A001500 
25114AB03100 
2S114AB03200 
25114AB03300 
25114AB03400 
25114AB03500 
25114AB03600 
25114AC00100 
2S114AC00200 
2S114AC00400 
2S114AC00500 
25114AC00600 
2S114AC00601 
25114AC00700 
25114AC01000 
IN TREE GROVE 
564.51 
184.39 
217.97 
3525.07 
2455.40 
3753.19 
4217.06 
353.67 
5265.50 
3831.89 
3879.57 
2.97 
572.77 
1127.39 
229.21 
543.40 
206.92 
56196.71 
73448.69 
8733.68 
39154.01 
5085.07 
4621.05 
16570.49 
72525 .65 
1807.74 
9284.04 
53591.65 
196749.74 
26903 .41 
16192.32 
39488.56 
9364.74 
6968.30 
140643.56 
493.97 
1365.03 
41582 .02 
183265.89 
36564.46 
45226.76 
62665 .79 
391.31 
3867.83 
5626.44 
6233.15 
4455.95 
204.41 
1243.09 
2731.70 
3047.91 
9641.92 
209694.87 
35720.55 
217413.88 
699.96 
TAXLOT SIZE (sq ft) 
OUTSIDE TREE GROVE 
6405.09 
3736.01 
4573.63 
5622.53 
7127.80 
5394.41 
4494.94 
6180.33 
7366.90 
3573.31 
4832.43 
4353 .03 
4218.83 
179.41 
3255.59 
2941.40 
3277.88 
25696.09 
19769.71 
22629.52 
921.19 
4498.13 
9318.15 
20891.11 
9802.75 
2548.26 
108763.56 
146784.35 
44572.66 
207449.39 
184619.28 
1457.84 
187526.46 
23959.30 
143367.64 
243442.03 
2217145.77 
109571.18 
309833.31 
72771.14 
135547.24 
857321.41 
9627.49 
7893.37 
8312.76 
11626.45 
9047.65 
8943.19 
7468.91 
7287.10 
9148.89 
47421.68 
67782.33 
1305.45 
467784.92 
7576.44 
TOTAL 
6969.60 
3920.40 
4791.60 
9147.60 
9583 .20 
9147.60 
8712.00 
6534.00 
12632.40 
7405 .20 
8712.00 
4356.00 
4791.60 
1306.80 
3484.80 
3484.80 
3484.80 
81892.80 
93218.40 
31363.20 
40075.20 
9583.20 
13939.20 
37461.60 
82328.40 
4356.00 
118047.60 
200376.00 
241322.40 
234352.80 
200811.60 
40946.40 
196891.20 
30927.60 
284011 .20 
243936.00 
2218510.80 
151153.20 
493099.20 
109335.60 
180774.00 
919987.20 
10018.80 
11761.20 
13939.20 
17859.60 
13503.60 
9147.60 
8712.00 
10018.80 
12196.80 
57063 .60 
277477.20 
37026.00 
685198.80 
8276.40 
GROVE NUMBER 
90 
90 
90 
90 
90 
90 
90 
90 
90 
90 
90 
90 
90 
90 
90 
90 
90 
91 
93 
93 
93 
93 
93 
93 
93 
93 
93 
93 
93 
93 
93 
93 
92 
92 
93 
97 
97 
97 
97 
97 
97 
101 
99 
99 
99 
99 
99 
99 
99 
99 
99 
99 
99 
99a 
100 
99a 
City o f Tigard Urban Forem y Code Rc,·isions I Volume 11 I 417 
GROVE TOTAL ACRES 
2.53 
2.53 
2.53 
2.53 
2.53 
2.53 
2.53 
2.53 
2.53 
2.53 
2.53 
2.53 
2.53 
2.53 
2.53 
2.53 
2.53 
1.29 
21.15 
21.15 
21.15 
21.15 
21.15 
21.15 
21.15 
21.15 
21.15 
21.15 
21.15 
21.15 
21 .15 
21.15 
2.27 
2.27 
21.15 
7.08 
7.08 
7.08 
7.08 
7.08 
7.08 
19.91 
5.89 
5.89 
5.89 
5.89 
5.89 
5.89 
5.89 
5.89 
5.89 
5.89 
5.89 
3.21 
15.39 
3.21 
TAXLOT SIZE (sq ft) 
TLID IN TREE GROVE OUTSIDE TREE GROVE TOTAL GROVE NUMBER GROVE TOTAL ACRES 
2S114AC01100 1727.41 7420.19 9147.60 99a 3.21 
2S114AC01200 1022.15 5947.45 6969.60 99a 3.21 
2S114AC01300 1499.68 6341.12 7840.80 99a 3.21 
2S114AD04700 45303.51 80149.29 125452.80 99a 3.21 
2S114BA12400 1142 .19 6263.01 7405.20 96 6.50 
2S114BA13400 203016.84 19574.76 222591.60 96 6.50 
25114BA15400 1495.24 6345.56 7840.80 96 6.50 
25114BA15500 943.76 5154.64 6098.40 96 6.50 
25114BA15600 858.15 5675.85 6534.00 96 6.50 
25114BA15700 646.20 5452.20 6098.40 96 6.50 
25114BA15800 1537.01 4561.39 6098.40 96 6.50 
25114BA15900 1617.74 4916.26 6534.00 96 6.50 
25114BA16000 1249.33 4849.07 6098.40 96 6.50 
25114BA16100 1523.06 5010.94 6534.00 96 6.50 
25114BA16200 1415.01 4247.79 5662.80 96 6.50 
25114BA16300 3134.44 3399.56 6534.00 96 6.50 
25114BA16400 2457.42 4512.18 6969.60 96 6.50 
25114BA16500 3029.00 6118.60 9147.60 96 6.50 
25114BA16700 453 .13 11308.07 11761.20 96 6.50 
25114BA17300 38470.32 9881.28 48351.60 96 6.50 
25114BA17800 543 .51 5634.16 6177.67 96 6.50 
25114BA18100 19504.17 8470.43 27974.61 96 6.50 
25114BC00800 4518.70 8549.30 13068.00 100 15.39 
25114BC00900 5315 .80 6881.00 12196.80 100 15.39 
25114BC01000 1905 .90 9419.70 11325.60 100 15.39 
25114BC01400 87490.43 11390.77 98881 .20 100 15.39 
25114BC05200 120840.66 25085.34 145926.00 100 15.39 
25114BD01400 42876.22 109148.18 152024.40 100 15.39 
25114BD04200 59310.64 34343 .36 93654.00 100 15 .39 
25114BD04300 38594.77 97312.43 135907.20 100 15.39 
25114DA00100 4937.09 1063154.11 1068091.20 101 19.91 
25114DA00300 18258.96 285354.24 303613.20 101 19.91 
25114DB00100 826160.67 522892.53 1349053 .20 101 19.91 
25114DB00200 5678.45 2597.95 8276.40 101 19.91 
25115AA01500 15518.09 21943.51 37461.60 95 3.76 
25115AA01600 14338.72 4392.08 18730.80 95 3.76 
25115AA01700 32380.05 10308.75 42688.80 95 3.76 
25115AA01800 17008.51 6949.49 23958.00 95 3.76 
25115AA01900 16499.84 14863 .36 31363.20 95 3.76 
25115AA05500 1596.94 8421.86 10018.80 95 3.76 
25115AA06800 6150.85 32181.95 38332.80 95 3.76 
25115AA10800 6267.60 9849.60 16117.20 95 3.76 
25115AD03801 7606.26 17222.94 24829.20 95 3.76 
25115AD07600 46330.06 5941.94 52272.00 95 3.76 
25115AD07700 75096.08 10281.52 85377.60 100 15.39 
23304336.44 36167285.44 59471621.87 
Total Acres 544.10 830.29 1365.28 
City of Tigard Urban l'orc,try Code ReYi,ions I \'olumc II I 41 8 
Urban Forestry Code Revisions 
Staff Report and Fin~ings 
City of Tigard Urban Forestry Code Revisions I Volume II I 419 

(UFCRP, Volume II) 
STAFF REPORT TO THE 
CITY COUNCIL 
FOR THE CITY OF TIGARD, OREGON 
SECTION I. 
FILENAME: 
CASE NOS: 
APPLICANT: 
PROPOSAL: 
LOCATION: 
ZONING: 
COMPPLAN: 
APPLICABLE 
REVIEW 
CRITERIA: 
SECTION II. 
APPLICATION SUMMARY 
URBAN FORESTRY CODE REVISIONS PROJECT 
Comprehensive Plan Amendment (CPA) 
Development Code Amendment (DCA) 
City of Tigard 
13125 SW Hall Boulevard 
Tigard, OR 97223 
120 DAYS= N/A 
CPA 2011-00004 
DCA 2011-00002 
To implement the city's Comprehensive Plan, as recommended by the Urban 
Forestry Master Plan, the City of Tigard is proposing a Comprehensive Plan 
Amendment adopting the "Significant Tree Groves Map" (Exhibit A) and Tigard 
Development Code (Title 18) Amendments to Chapters 18.115, 18.120, 18.310, 
18.330, 18.350, 18.360, 18.3 70 18.390, 18.530, 18.610, 18.620, 18.630 18.640, 
18.715,18.745, 18.775, 18.790, and 18.798. 
Citywide 
All zoning classifications 
All Comprehensive Plan Designations 
Community Development Code Chapters 18.380 and 18.390; Comprehensive Plan 
Goals 1, Environmental Quality; 7, Hazards; 8, Parks Recreation, Trails and Open 
Space; 9, Economic Development; 10, Housing; 11, Public Facilities and Services; 12, 
Transportation; 13, Energy Conse1vation; and 14, Urbanization; Downtown; 
METRO's Urban Growth Management Functional Plan Titles 1, 3, 12 and 13; 
Statewide Planning Goals 1, 2, and 5 through 14. 
STAFF RECOMMENDATION 
Staff recommends that the City Council concur witl1 the Planning Commission and find tl1at this request for 
a Comprehensive Plan Amendment and D evelopment Code Amendments meets the necessary approval 
criteria according to the findings found in Section IV of this report. Therefore, staff recommends City 
Council APPROVE CPA 2011-00004 and DCA 2011-00002. 
SECTION III. BACKGROUND INFORMATION 
Project Histoty 
The City of Tigard has a proud history of commitment to preserving, enhancing and maintaining its urban 
forest. The city's trees provide an important backdrop for life in Tigard. Unlike natural forests or managed 
URBAN FORESTRY CODE REVISION PROJECT- Staff Report to the City Council 
CPA 2011 -00004 / DCA 2011 -00002 
City o f Tigard Urban Fores try Code Re,·isions I Volume 11 I 421 
PAGE 1 OF40 
timberland, T igard 's urban fores t is a mosaic o f native fores t remnants and planted landscapes interspersed 
with buildings, roads and o ther elements of the urban environment. 
On June 3, 2008, Tigard City Council adopted an Urban Fores t section as part of its Comprehensive Plan 
in order to establish broad goals and policies to guide the long-term management and enhancement o f the 
urban fores t. During this process, the public voiced concern over existing D evelopment Code provisions, 
particularly with regard to tree mitiga tion standards. D evelopment interes ts felt the standards were overly 
punitive and setved as impediments to development. E nvironmental interes ts felt the standards were 
ineffective at achieving the goal o f a healthy and sustainable urban fores t. 
Soon after adoption, the H ome Builders Association o f Metropolitan Portland filed a no tice o f intent to 
appeal with the Land Use Board o f Appeals. T he Urban Forest section o f Comprehensive Plan was 
voluntarily remanded as a result. While the city was unable to fully understand the specific concerns o f the 
H ome Builders Association, they did take the opportunity to provide more detailed findings to further 
support and explain the rationale for the city's urban fores t goals and policies. T hese additional findings 
can be found in the Tree Values Memo beginning on page 149 of Volume V o f the Adoption Volumes, 
which are more fully described on page 4 of this staff report. On August 10, 2010, Tigard City Council 
readopted the Urban Fores t section of the Comprehensive Plan with the additional findings. For 
reference, the Urban Forest section o f the Comprehensive Plan is included beginning on page 292 in 
Volume V. 
To create a roadmap that implements the urban fores t goals and policies in the Comprehensive Plan, 
T igard City Council directed staff to develop an Urban Forestry Mas ter Plan, which is included in its 
entirety beginning on page 207 of Volume V. T he Urban Forestry Mas ter Plan was developed through a 
public process, which included specific outreach and involvement o f development and environmental 
interes ts, as well as the community at large. On November 10, 2009, the Urban Forestry Mas ter Plan was 
accepted by Council. It outlines issues with the management and regulation of the urban fores t and 
detailed recommendations for addressing those issues. Among the recommendations are sugges ted code 
revisions to support the implementation o f the urban fores t goals and policies in the Comprehensive Plan. 
T he main issues and recommendations in the Urban Forestry Master Plan include: 
Issues: 
1. The code does no t promote the presetvation o f high quality trees. 
2. The mitiga tion structure encourages overplanting and the presetva tion of large diameter trees 
that are o ften less likely to survive development in1pacts. 
3. The fees for tree removal are excessive. 
4. The code unfairly penalizes those property owners with existing trees more than those owners 
without trees . 
5. The code is administratively difficult to implement because it is challenging to track pro tected 
and replacement trees in the years and decades following development. 
6. The code lacks specificity and has conflicts between various provisions, which present 
adrninistrative challenges for the city. 
7. The code does no t require sustainable installation and maintenance methods for trees. 
8. The code does no t provide flexible standards and incentives for preserving native tree groves. 
Recommendations: 
1. Update T igard 's urban fo restry standards for development. 
2. E nsure urban forestry standards promote sustainable design and maintenance of the urban 
fores t. 
3. Es tablish an incentive-based program to presetve Tigard 's remaining groves o f native trees. 
4. D evelop an equitable and efficient hazard tree identification and abatement program. 
5. Improve management o f the urban fores t by ensuring information is readily available for both 
the city and the public when making decisions. 
6. Promo te community-wide participation in urban fores t stewardship. 
URB.-\N FORESTRY CODE RE \'1SION PROJECT- Staff Report to the City C0tmcil 
CP.\ 201 1-00004/ D C -\ 201 1-00002 
CitY ofTigan.l Urban l'orcs try Code Rc,·isions I \'olumc II I 422 
PAGE 2 OF 40 
To implement the Comprehensive Plan, as recommended by the Urban Forestry Master Plan, City Council 
directed staff to undertake a major update of Tigard's urban forestry related code provisions. Developed 
over two years from February 2010 to the spring of 2012, the Urban Forestry Code Revisions Project 
reflects Tigard City Council's direction for a comprehensive update of the city's urban forestry related 
code provisions with enhanced public involvement. 
The Urban Forestry Code Revisions Project has involved ongoing, extensive collaboration with city 
residents and stakeholders, internal city departments and outside agencies. In February 2010, a Citizen 
Advisory Committee was appointed by Council to ensure representation of a broad set of viewpoints 
during the update process. This committee included two planning commissioners, two Tree Board 
members, two Parks Board m embers, two developers (including a representative for the Home Builders 
Association), one certified arborist, one natural resource advocate and one at-large citizen. In January 
2011, the Citizen Advisory Committee timeline was extended to ensure ample time for the committee to 
discuss code topics. In finalization, the committee reached consensus on a set of guiding principles for 
each of the code topics. 
A Technical Advis01y Committee was formed at the same time as the Citizen Advisory Committee. The 
Technical Advisory Committee included city staff and representatives from outside agencies to advise the 
project management team on the technical aspects of the code during the update process. 
A public involvement plan was developed specifically for the project, to provide enhanced opportunities 
for participation for the overall community throughout the process. This plan included outreach at city 
events such as the Balloon Festival and Farmers Market, an email newsletter specific to the Urban Forestry 
Code Revisions Project, three open houses and a variety of other methods for community feedback. 
The draft urban foresuy code was peer reviewed by outside development and urban forestry experts in 
October 2011, to provide additional assurance of technical soundness. 
From this collaborative process emerged the staff proposed draft code amendments, which Planning 
Commission received public testimony and deliberated on during four public hearings from February 
through May of 2012. On May 7, 2012 the Planning Commission unanimously recommended City Council 
approval of the land use elements of the Urban Forestry Code Revisions. While the commission's formal 
recommendation to council was limited to the land use elements of the proposal, the commission also 
reviewed proposed changes to the Tigard Municipal Code and the proposed Urban Forestry Manual. 
Based on their review, the commission found these proposals are consistent with and supportive of the 
recommended land use elements. A detailed description of the Planning Commission deliberations and 
decisions is included beginning on page 3 ofVolume V. 
The Planning Commission recommended Development Code Amendments (DCA) to Title 18 (Vol. II, 
pp. 3) and Comprehensive Plan Amendment (CPA) adopting the significant tree groves map (Exhibit A) 
are the subject of this application and staff report. The CPA allows for the significant tree grove 
preservation incentives (Vol. II, pp. 153-161), as required by Statewide Planning GoalS rule requirements. 
Amendments proposed to the Tigard Municipal Code Chapters 1.16, 6.01, 6.02, 7.40, 8.02- 8.18, 9.06, and 
9.08, address the management of trees when land use regulations are not applicable. For example, these 
non-land use amendments would address trees that are hazards to people or property outside the land use 
process. While they are not part of the CPA or DCA in this application, they are included in the full 
package being considered by City Council (Vol. III). 
In addition, proposed administrative rules in the form of an Urban Forestry Manual included in the full 
package being considered by City Council (Vol. IV). The proposed Urban Foresuy Manual contains 
detailed specifications and procedures to support implementation of the proposed code. The Urban 
Forestry Manual is provided for reference only; it does not contain land use regulations and is not part of 
the CPA or DCA in this application. 
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City o f Tigard Urban l'orcstry Code Revisions I Volume II I 423 
PAGE 3 OF 40 
Volumes I, II, Ill, IV and V ofthe Urban Fores try Code Revisions 
T he Urban Forestry Code Revisions project is presented in five volumes. Volume I provides the project 
overv iew and describes the process used to develop all of the elements. Volume II is the land use elements 
o f the code, and Volume III the non land use elements. Volume IV contains the Urban Forestry Manual. 
Volume V contains technical reports and research that contributed to the code revisions along with details 
o f the public input and deliberations to date. 
Volume I I Project O verview 
Project Overview includes the following sections: 
• Pro ject Introduction 
• O verview of K ey E lements 
• K ey E lement Summaries 
• Urban Forestry Standards for D evelopment 
• Tree G rove Preservation Incentives 
• T ree Permit Requirements 
• H azard Trees 
• Urban Forestry Manual 
Appendix A includes additional detail about the information used to shape the Urban Forestry Code 
Revisions Project, and includes the following sections: 
• Process summary 
• Summary of Community Ideas and Concerns 
• Summary o f Planning Commission D eliberations 
• E xisting Conditions 
Volume II I Land Use Elements 
Community Development Code (Title 18) is the Planning Commission's recommended draft o f the 
D evelopment Code. This section includes commentary on the amendments. 
Peer Review demonstrates how the Planning Commission's recommended draft o f the D evelopment 
Code and Urban Forestry Manual will work in application. 
ESEE Analysis is a report that addresses Statewide Planning Goal 5 - Na tural Resources requirements for 
the preserva tion of Significant Tree Groves. 
Staff Report and findings includes the staff recommendation for approval o f the land use elements (Title 
18 and the Comprehensive Plan Amendment) and the findings that demonstrate the land use elements 
meet the necessary approval criteria. 
Volume III I Non Land Use Elements 
Tigard Municipal Code is the staff proposed draft o f the Municipal Code (Title 8 and other Municipal 
Code titles). T his section includes commentary on the amendments. 
Volume IV I Urban Fores try Manual (Administrative Rules) 
Urban Forestry Manual consists o f administrative rules that implement the technical details o f the urban 
fores try related code provisions in Title 8, Title 18 and o ther applicable titles in the Tigard Municipal 
Code. 
URJB .N FORESTRY CODE RE\TTSIO N PROJ ECT - Staff Reporr ro th e City Cow1eil 
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Volume V I Additional Background Materials 
Planning Commission D eliberations details Planning Commission discussion and decisions during the 
public hearing process. 
Amendment Requests Document for the Planning Commission lists code amendment requests 
received in response to the first Planning Commission public hearing and staff responses. 
Outstanding Issues for the Urban Forestry Code Revisions includes additional information on the 
outstanding issues that were further deliberated by the Planning Commission before making their final 
recommendation to City Council on May 7, 2012. 
Log of Input lists the input received and any code changes from the last meeting of the CAC to the staff 
proposed draft of the Urban Forestry Code Revisions to Planning Commission. 
CAC Guiding Principles includes the consensus view of the Citizens Advisory Committee (CAC) 
developed to help guide the legislative adoption process. 
Tree Values includes information and current research on the enviromnental, economic, social and 
aesthetic benefits of trees. 
Canopy Standards explains the reasons for adopting tree canopy cover requirements as well as the 
methods used to arrive at the requirements . 
Soil volume details research about the soil volume required to support a mature tree canopy. 
Tree Canopy Fee discusses research used to develop a square foot value for tree canopy. 
Regulatory Comparison is an excerpted report prepared by Metro and the Audubon Society that 
summarizes and compares regional urban forestry programs and regulations. 
Urban Forestry Master Plan is the City of Tigard's recommended plan for achieving the urban forestry 
goals in the Comprehensive Plan. 
Goal 5 Applicability 
The CPA would incorporate the significant tree grove map (Exhibit A) into the city's Comprehensive Plan 
Resource Document 01 olume 1) as a new Goal 5 natural resource inventory. The DCA in Section 
18. 790.050.D includes regulatory incentives and flexible standards to protect significant tree groves listed 
in the inventory. Oregon Administrative Rule (ORS) 660-23-0250(3) requires local governments to address 
GoalS requirements when a post acknowledgement plan amendment" ... creates ... a resource list ... or a land 
use regulation adopted in order to protect a significant Goal 5 resource." Therefore, the significant tree 
grove map and regulatory incentives and flexible standards are subject to Goal 5 requirements (further 
described in the Tree Grove ESEE Analysis 01 ol. II, p. 219)). The analyses and conclusions found in the 
Statewide Planning Goal Analysis section of the Tigard Goal 5 ESEE Analysis for Significant Tree Groves 
(pages 3-4 through 3-58) explains how the city adhered to the Goal 5 process and meets the applicable 
criteria. Those analyses and conclusions are hereby explicitly incorporated into the findings of this staff 
report. 
However, Goal 5 requirements are not applicable to recommended code amendments that support general 
urban fores t enhancem ent activities, such as tree planting and preservation, when not associated with 
significant tree groves. These activities do not create or amend a resource list or land use regulation 
adopted in order to protect a Goal 5 resource. 
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Procedural Note 
For the purposes o f review and adoption, the urban forestry code revisions are com prised o f four basic 
elements: 
1) The significant tree groves map, which is the subject o f the recommended CPA; 
2) Amendments to the land use regulations in Title 18, which are the subj ect o f the D CA; 
3) Amendments to the non-land use regulations in all other titles except Title 18, which are not part 
of this application; and 
4) Administrative rules in the Urban Foresu-y Manual, which are also non-land use regulations and 
also not part o f this application. 
Because of Oregon land use law, the land use elements (CPA and D CA) will be adopted by separate 
ordinance from the proposed non-land use amendments (Tigard Municipal Code titles o ther than Title 
18). The Urban Forestry Manual will be adopted as an administrative rule through a separate rule malting 
process in TMC 2.04, which also allows future amendments to these technical specifications using the 
same process. 
SECTION IV. APPLICABLE CRITERIA AND FINDINGS 
APPLICABLE CITY OF TIGARD COMMUNITY DEVELOPMENT CODE (TITLE 18) 
Chapter 18.380. ZONING MAP AND TEXT AMENDMENTS 
"18.380.020 Legislative Amendments to this Title and Map 
A. Legislative amendments. Legislative zoning map and text amendments shall be 
undertaken by means of a T ype IV procedure, as governed by Section 18.390.060G." 
T he CPA and D CA would es tablish rules and regulations to be applied generally to all similarly affected 
properties throughout the City of Tigard. Therefore, the application is being processed as a Type IV 
procedure, which is a legislative amendment, as governed by Section 18.390.060.G. 
Chapter 18.390. DECISION-MAKING PROCEDURES 
"18.390.B.4. T ypes defined. There are four types of decision-making procedures, as follows: ... 
4. T ype IV Procedure. T ype IV procedures apply to legislative matters. Legislative matters 
involve the creation, revision, or large-scale implementation of public policy. T ype IV 
matters are considered initially by the Planning Commission with final decisions made by 
the City Council." 
The CPA and D CA would result in the creation, revision and large-scale implementation of the city's 
urban foresu-y goals and policies in the Comprehensive Plan. T herefore, the application will be reviewed 
under the Type IV procedure as detailed in the Section 18.390.060.G. In accordance with this section , the 
CPA and D CA was initially considered by the Planning Commission and they recommended City Council 
adopt the changes in mahng the final decision. 
"18.390.060.G. Decision-making considerations. The recommendation by the Commission and 
the decision by the Council shall be based on consideration of the following factors: 
1. The Statewide Planning Goals and Guidelines adopted under Oregon Revised Statutes 
Chapter 197; 
2. Any federal or state statutes or regulations found applicable; 
3. Any applicable METRO regulations; 
4. Any applicable comprehensive plan policies; and 
5. Any applicable provisions of the City' s implementing ordinances." 
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The applicable decision-making considerations include the following: 
• Applicable Statewide Planning Goals- Goals 1, 2, and 5 through 14. 
• Applicable federal and state of Oregon statutes- ORS197. 
• Applicable METRO regulations- Titles 1, 3, 12 and 13. 
• Applicable Comprehensive Plan policies - Goals 1, Citizen Involvement; 2, Land Use Planning; 
5, Natural Resources; 6, E nvironmental Quality; 7, Hazards; 8, Parks Recreation, Trails and 
Open Space; 9, Economic Development; 10, Housing; 11, Public Facilities and Services; 12, 
Transportation; 13, E nergy Conservation; and 14, Urbanization; 15, Downtown. 
• Applicable city ordinances - TMC Chapters 18.380 and 18.390. 
CONCLUSION: The review criteria listed above are applicable to the CPA and DCA in Volume II. The 
CPA and DCA were reviewed through the Type IV legislative procedure. The Planning Commission and 
Council are basing their decisions on applicable federal, state, METRO, and local policies and regulations, 
which are enumerated and addressed in this staff report. Therefore, the applicable Tigard Development 
Code provisions are met. 
APPLICABLE CITY OF TIGARD COMPREHENSIVE PLAN POLICIES 
INTRODUCTION 
(Excerpt from p. I-3 of the Comprehensive Plan): 
"As the comprehensive plan is "comprehensive" in nature, there are no parts that can be 
considered separately from others. Plan goals and policies are intended to be supportive of one 
another. However, if conflicts arise between goals and policies when using the Plan, the City has 
an oblig ation to make findings that indicate why the goal or policy being supported takes 
precedence. This involves a decision-making process on the part of the city that balances and 
weighs the applicability and merits of the goals and policies that are in contention." 
As described in the Project History section of this report, the Urban Forestry Code Revisions Project 
reflects Tigard City Council's direction for a comprehensive update of the city's urban forestry related 
code provisions with enhanced public involvement. 
The Urban Forestry Code Revisions Project has involved ongoing, extensive collaboration with city 
residents and stakeholders, internal city departments, outside agencies and Planning Commission 01 ol. I, p. 
26). 
From this collaborative process emerged the Planning Commission CPA and DCA described in this report 
which represent a balance between the range of interests involved in the process, as well as balance 
between the goals and policies in the Comprehensive Plan. 
The primary balancing efforts have focused on developing tree canopy requirements that balance the 
community's desire for trees, development, and open space. The Citizen Advisory Committee reached 
consensus to draft achievable and balanced tree canopy requirements for development that are tiered 
based on zoning district. For example, development in low density residential areas would be required to 
have more trees than in areas of dense zoning, such as Downtown Tigard 01ol. V, p. 141). 
To implement the consensus of the Citizen Advisory Committee, staff analyzed possible percent tree 
canopy for each zoning district using the same methodology developed to set tree canopy goals for the 
Urban Forestry Master Plan as well as an updated methodology using Light Detection and Ranging 
(LiDAR) technology 01ol. V, p. 159). 
The results of these analyses were then used in conjunction with the nurumum percent landscaping 
requirements in the Tigard Development Code to place the various zoning districts within one of three 
tiers. The exception is school sites, which were placed in the "dense zoning" tier 3 to ensure sufficient 
room for sports fields 01 ol. V, p. 161 ). 
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Staff and outside consultants then tes ted the tiered requirements on a wide range o f development projects 
to ensure the requirements are in fact achievable, result in a reasonable balance between trees, 
development and open space, and do no t force payment o f fees in lieu or discretionary review for typical 
pro jects. 
T he peer review results demonstrate that the requirements are achievable without payment o f fees in lieu 
or discretionary reviews 01 ol. II, p . 185). 
While the Planning Commission kept with the CAC consensus, key changes made to the proposal by 
Planning Conunission, in response to public input, include: 
• Reducing the amount o f tree canopy required for higher density residential development; 
• Allowing required tree canopy to be measured for the overall development site rather than 
individual lo ts fo r higher density residential development and non-residential development; and 
• G ranting bonus credits for planting native trees . 
A detailed description of the Planning Commission deliberations and decisions can be found beginning on 
page 3 o f Volume V. 
Based on these analyses, the Planning Commission concluded that the recommended tree canopy 
requirements balance the community's desire for trees, development and open space, and the goals and 
policies of the Comprehensive Plan as articulated in the Introduction. 
CITIZEN INVOLVEMENT 
"GOAL: 
1.1 Provide citizens, affected agencies, and other jurisdictions the opportunity to participate in 
all phases of the planning process." 
As described in the Process Summary 01 ol. I, p . 26) , the city has provided Tigard clUzens, affected 
agencies and o ther jurisdictions multiple and varied opportunities to participate in all phases o f the urban 
fores try planning process . T his included 11 Citizen Advisory Committee meetings where people 
representing diverse interes ts and viewpoints discussed and reviewed code concepts and language at 11 
meetings, hos ted by an independent facilitator. In addition, a Technical Advisory Committee, which 
included representatives from multiple city departments such as Public Works and Community 
D evelopment and outside agencies such as the O regon D epartment o f Transportation and Clean Wa ter 
Service met 14 times to discuss and review code concepts and language resulting from the Citizen 
Advisory Committee process. 14,225 public hearing no tices, consistent with Measure 56 requirements, 
were sent to all T igard property owners on J anua1-y 13, 2012. Public hearing notices were also provided to 
interes ted parties on Janual-y 17, 2012, to affected agencies on January 20, 2012 and published in the 
Tigard Times on January 19, 2012. 
T he Planning Commission received public tes timony and deliberated on the proposed CPA and D CA 
during four public hearings from February through May 2012. T his included consideration of 85 
amendment requests that were generated from their February 6, 2012 hearing. Using this input the 
Planning Commission revised the proposed CPA and D CA, and then made a unanimous recommendation 
for council approval. 
T he Planning Commission reconunended CPA and D CA will be further considered through the public 
hearing process at City Council prior to adoption . The tentative council schedule is as follows: 
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M eeting 
D ate M eeting T yp e Meeting Purpose 
July 10, 2012 Council Study Session 
Staff reviews legislative adoption process with council and 
distributes UFCR materials. 
July 11, 2012 Project Staff with Provide broad overview of proposal components and 
to Councilors describe / discuss elements in more detail with councilors, July 23, 2012 as desired, in advance of public hearings. 
Receive staff report, listen to public testimony and identify 
July 24, 2012 Council Public Hearing issues of most concern for additional discussion at the 
August 28, 2012 meeting. 
Aug 28,2012 Council Work Session Staff report on issues of most concern and council direction on how to address each issue. 
Receive staff report on how issues of most concern were 
Oct 9, 2012 Council Public Hearing addressed, accept public testimony on those issues and 
make a final decision on adoption. 
Nov 13, 2012 Council Public Hearing Additional hearing similar in format as previous meeting, if 
needed. 
The Urban Forestry Code Revisions process demonstrates that cltlzens, affected agencies and other 
jurisdictions have been provided the opportunity to participate in all phases of the planning process 
consistent with this policy. 
"GOAL: 
1.2 Ensure all citizens have access to: 
A. opportunities to communicate directly to the City; and 
B. information on issues in an understandable form." 
"POLICIES: 
5. The City shall seek citizen participation and input through collaboration 
with community organizations, interest groups, and individuals in 
addition to City sponsored boards and committees." 
As described in the Process Summary 0' ol. I, p. 26), the Citizen Advisory Committee included 
representatives from city boards such as the Tree Board, Parks Boards, and Planning Commission, 
representatives from community organizations and interests groups such as the Tualatin Riverkeepers and 
HBA and citizens at large. These and other public involvement opportunities demonstrate that the city has 
sought citizen participation and input through collaboration with community organizations, interest groups 
and individuals in addition to city sponsored boards and committees consistent with this policy. 
"6. The City shall provide opportunities for citizens to communicate to 
Council, boards and commissions, and staff regarding issues that 
concern them." 
The community had opportunities to participate in the Citizen Advisory Committee process by providing 
written, electronic and verbal communication at each Citizen Advisory Committee meeting. Staff provided 
three open house opportunties to provide opportunities for additional community feedback. Two open 
houses allowed opportunties for property owners with significant tree groves to provide input to the city 
during the inventory phase and development of regulatory incentives and flexible standards. An additional 
open house provided opportunties for the overall community to provide feedback on additional urban 
forestry code amendments, which are not subject to the Goal 5 rule requirements. Therefore, the city has 
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provided Tigard citizens the opportunity to communicate to Council, boards and commissions, and staff 
regarding urban forestry issues that concern them, consistent wirh this policy. 
LAND USE PLANNING 
"GOAL: 
2.1 Maintain an up-to-date Comprehensive Plan, implementing regulations 
and action plans as the legislative foundation of Tigard's land use 
planning program." 
"POLICIES: 
1. The City's land use program shall establish a clear policy direction, comply with state and 
regional requirements, and serve its citizens' own interests." 
In 2008 the city completed its periodic review and update o f its Comprehensive Plan, which has been 
acknowledged by Oregon D epartment of Land Conservation and D evelopment DLCD as consistent with 
Statewide Planning Goals. Included within the Comprehensive Plan is an Urban Forest section, which was 
initially adopted on June 3, 2008, and readopted on August 10, 2010, with additional findings that further 
support the goals and policies in the Urban Forest section. The U rban Forest section (Vol. V, p . 292) and 
the additional findings can be found in the Tree Values Memo (Vol. V, p. 149). On N ovember 10, 2009, 
City Council accepted the Urban Forestry Master Plan as consistent with, and supportive of, the urban 
fores try goals and policies in the Comprehensive Plan. The Urban Forestry Mas ter Plan set realistic 
timelines and provides a balanced framework for implementing updates to the city's urban fores try code 
provisions, policies and programs (Vol. V, p . 207). T he CPA and D CA have been guided by these pas t 
planning processes, which have es tablished clear policy direction in compliance with state and regional 
requirements and se1ve citizen's interes ts, consistent with this policy. 
"2. The City's land use regulations, related plans, and implementing actions shall be 
consistent with and implement its Comprehensive Plan." 
The Urban Forestry Mas ter Plan provides a roadmap in the form of a matrix for implementing urban 
forestry goals and policies in the Comprehensive Plan (Implementation Matrix,Vol. V, p . 216). The CPA 
and D CA implement the recommendations in the Urban Forestry Master Plan matrL'C. Therefore, they are 
consistent with related plans and implement the Comprehensive Plan, as required by this policy. 
"3. The City shall coordinate the adoption, amendment, and implementation of its land use 
program with other potentially affected jurisdictions and agencies." 
Reques t for comments on the proposed CPA and D CA were sent to Metro- Land Use and Planning, 
Washington County D epartment of Land Use & Transportation, U.S. Army Corps o f E ngineers, Oregon 
D epartment of State Lands, Oregon D epartment of Land Conservation and D evelopment, Oregon 
D epartment o f Fish and Wildlife, Oregon D epartment of E nvironmental Quality, T ualatin Valley Fire & 
Rescue, Tigard-Tualatin School District 23J , and the cities o f Tualatin, Lake O swego, Beaverton, King City 
and Durham. Representatives of the Oregon D epartment o f Transportation and Clean Water Services 
were also members o f the Technical Advis01y Committee. D LCD was provided the opportunity to 
comment and coordinate the application for the Post Acknowledgement Plan Amendment process per 
ORS 197.61 0. T herefore, the city has coordinated the adoption, amendment and implementation of the 
CPA and D CA with potentially affected jurisdictions and agencies consistent with this policy. 
"4. The City's land use program shall promote the efficient use of land through the creation of 
incentives and redevelopment programs." 
T he D CA in Section 18.790.050.C (Vol. II , p . 149) include incentives and flexible standards for the 
preserva tion and planting o f individual trees, while accommodating development. These incentives and 
flexible standards include lo t size averaging, setback adjustments and parking adjustments. 
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In addition, incentives and flexible standards for the preserva tion of significant tree groves are 
recommended in Section 18. 790.050.D (Volume II, p . 153). T hese incentives and flexible standards 
include density transfer, setback adjustments and additional building height to preserve significant tree 
groves, while accom odating development. Therefore, the city has prom oted the efficient use of land 
through incentives and flexible standards that accommodate the preserva tion and planting o f individual 
trees and the preservation o f significant tree groves, consistent with this policy. 
"7. The City's regulatory land use maps and development code shall implement the 
Comprehensive Plan by providing for needed urban land uses including: . . . 
E) Overlay districts where natural resource protections or special planning and regulatory 
tools are warranted." 
T he CPA establishes an overlay district for 70 significant tree groves covering 527 acres. As further 
described in the T ree G rove E SEE Analysis (Vol. II, p . 21 9) , Goal 5 rule requirements allow significant 
tree groves within the overlay to be eligible for the recommended incentives and flexible standards for 
their preservation in Section 18.790.050.D. The analyses and conclusions found in the Statewide Planning 
Goal Analysis section of the Tigard Goal 5 ESEE Analysis for Significant Tree G roves (page 3-4 through 
3-58) explains how the city adhered to the Goal 5 process and meets the applicable criteria. T hose 
analyses and conclusions are hereby explicitly incorporated into the findings of this staff report. T herefore, 
the CPA and D CA implement the Comprehensive Plan by creating an overlay district where natural 
resource protections and special planning and regulatory tools are warranted consistent with this policy. 
"12. The City shall provide a wide range of tools, such as planned development, design 
standards, and conservation easements that encourage results such as: . .. 
C) Protection of natural resources; 
D) Preservation of open space; and 
E) Reg ulatory flexibility necessary for projects to adapt to site conditions." 
Incentives and flexible standards for the preservation o f significant tree groves are recommended in 
Section 18.790.050.D, such as reduction of minimum density, density transfer, setback adjustments and 
additional building height to preserve significant tree groves while allowing development to adapt to site 
conditions. Significant tree groves are a Goal 5 natural resource and the recommended am endments would 
facilitate the protection of these resources, consistent with this policy. 
"15. In addition to other Comprehensive Plan goals and policies deemed applicable, 
amendments to Tigard's Comprehensive Plan/ Zone Map shall be subject to the following 
specific criteria: 
G) Demonstration that the amendment does not detract from the viability of the City's 
natural systems." 
T he CPA creates a significant tree grove overlay, which overlaps with sensitive lands defined in Chapter 
18.77 5, which together represent the city's natural systems. T he recommended flexible standards and 
incentives for preserving significant trees groves would enhance, rather than detract from the viability of 
the city's natural system s, consistent with this policy. 
"18. The Council may at any time, upon finding it is in the overall public interest, initiate 
leg islative amendments to change the Comprehensive Plan text, Plan/ Zoning Map(s) 
and/ or the Community Development Code." 
To implem ent the Comprehensive Plan as recommended by the Urban Forestry Master Plan , in February 
2010 City Council directed staff to undertake a comprehensive update of Tigard's urban forestry related 
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code prov1s10ns. The CPA and D CA reflect City Council direction for a comprehensive update of the 
city's urban fores try related code provisions, which they have found to be in the overall public interes t 
consistent with this policy. 
"20. The City shall periodically review and, if necessary, update its Comprehensive Plan and 
regulatory maps and implementing measures to ensure they are current and responsive to 
community needs, provide reliable information, and conform to applicable state law, 
administrative rules, and regional requirements." 
T he CPA and D CA amendments were developed in response to community needs identified through the 
Urban Forestry Mas ter Plan and Urban Forestry Code Revisions Projects. Both o f these projects involved 
a Citizen Advisory Committee to ensure conununity needs were well represented during the planning 
process. The CPA and D CA are current and responsive to the community's needs, as evidenced by the 
Citizen Advisory Committee's unanimously approved guiding principles (Vol. V, p . 139). 
In addition, the CPA creates a significant tree grove map (Exhibit A) , which provides reliable information. 
E ach significant tree grove was inventoried and assessed using Geographic Information Sys tem s (GIS) and 
site visits. T he inventory and assessment process is further described in the Tree G rove E SEE Analysis 
(Vol. II, p . 21 9) . The analyses and conclusions found in the Statewide Planning Goal Analysis section of 
the Tigard G oal 5 E SEE Analysis for Significant Tree Groves (page 3-4 through 3-58) explains how the 
city adhered to the G oal 5 process and meets the applicable criteria . T hose analyses and conclusions are 
hereby explicitly incorporated into the findings o f this staff report. T he CPA and D CA conform to 
applicable state, administrative rules, and regional requirements as identified in the findings for this staff 
report and the Tree G rove E SEE Analysis. Therefore, the CPA and D CA are consistent with this policy. 
"21. The City shall require all development to conform to site design/ development 
regulations." 
The Urban Forestry Plan requirements in Chapter 18.790 (Vol. II, p . 21 9) would continue to require an 
Urban Fores try Plan for land use projects that were previously required to conform to the chapter 
requirements. Two additional review types (Downtown D esign Review and Sensitive Lands Review) would 
also be required to conform to the chapter requirements. Therefore, the D CA would continue to require 
all land use projects, as well as two additional review types , to conform to urban forestry site design and 
development regulations, consistent with this policy. 
"22. The City shall identify, designate, and protect natural resources as part of its land use 
program." 
The CPA creates a significant tree grove overlay for 70 inventoried significant tree groves covering 527 
acres . T he T ree Grove ESEE Analysis (Vol. II, p . 21 9) provides grea ter context for the recommended 
overlay, which has been designated consistent with Goal 5 rule requirements. T he analyses and 
conclusions found in the Statewide Planning G oal Analysis section o f the Tigard G oal 5 E SEE Analysis 
for Significant Tree G roves (page 3-4 through 3-58) explains how the city adhered to the Goal 5 process 
and meets the applicable criteria. Those analyses and conclusions are hereby explicitly incorporated into 
the findings o f this staff report. The recommended flexible standards and incentives in Section 
18. 790.050.D (Vol. II , p . 153) are designed to facilitate the protection of significant tree groves consistent 
with this policy. It is important to note that Goal 5 rule requirements are not applicable to the preservation 
and planting of individual trees because individual trees are planted and preserved primarily for their 
aes thetic, air and water quality benefits, as further described in the Tree Values Memo (Vol. V, p . 149). 
"24. The City shall establish design standards to promote quality urban development and to 
enhance the community's value, livability, and attractiveness." 
T he D CA in Chapters 18.610- 18.640, 18.745 and 18.790 in Volume II, include design standards for the 
planting and preserva tion of individual trees, which are recognized for their aes thetic benefits as more fully 
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described in the Tree Values Memo (Vol. V, p. 149). The Tree Values memo explains that individual trees 
are proven to enhance property values and thereby promote quality urban development and enhance the 
community's value, livability and attractiveness, consistent with this policy. 
"GOAL: 
2.2 To enlarge, improve, and sustain a diverse urban forest to maximize the economic, 
ecological, and social benefits of trees." 
"POLICIES: 
1. The City shall maintain and periodically update policies, regulations, and standards to 
inventory, manage, preserve, mitigate the loss of, and enhance the community's tree and 
vegetation resources to promote their environmental, aesthetic and economic benefits." 
The Urban Forestry Standards for Development require an inventory and plan to manage, preserve and 
mitigate the loss of the trees as part of the development process (Vol. II, p. 3-184). Incentives in Chapter 
18.790, such as the Urban Forestry Plan requirements in Section 18.790.030 encourage the preservation 
and planting of trees, however a fee-in-lieu of planting or preservation is allowed to mitigate the loss of 
trees. 
In addition, the CPA would create a significant tree grove overlay for 70 inventoried significant tree groves 
covering 527 acres. The Tree Grove ESEE Analysis (Vol. II, p. 219) provides greater context for the 
recommended overlay, which has been designated consistent with Goal 5 rule requirements. The analyses 
and conclusions found in the Statewide Planning Goal Analysis section of the Tigard Goal 5 E SEE 
Analysis for Significant Tree Groves (page 3-4 through 3-58) explains how the city adhered to the Goal 5 
process and meets the applicable criteria. T hose analyses and conclusions are hereby explicitly 
incorporated into the findings of this staff report. Flexible standards and incentives are recommended in 
Section 18.790.050.D to facilitate preservation of significant tree groves (Vol. II, p. 153). 
Through these CPA and DCA , tl1e city is maintaining and updating its policies, regulations and standards 
to inventory, manage, preserve, mitigate the loss of and enhance the community's tree and vegetation 
resources to promote their envil:onmental, aesthetic and economic benefits consistent with this policy. 
"2. The City's various codes, regulations, standards, and programs relating to landscaping, 
site development, mitigation, and tree management shall be consistent with, and 
supportive of, one another; administration and enforcement shall be regulated and 
coordinated by the variously impacted departments." 
Tigard City Council directed staff to pursue a comprehensive update of the city's urban forestry code 
provisions to ensure the various code, regulations, standards and programs relating to landscaping, site 
development, mitigation and tree management are consistent with an supportive of, one another. Staff has 
paid particular attention to ensure consistency between the recommended land use regulations in Title 18 
and the non-land use regulations in other titles so adminstration and enforcement is coordinated before, 
during and after the development process. In addition, staff from variously impacted departments and 
outside agencies that have a role in urban forestry served on the Technical Advisory Committee to 
coordinate developing the urban forestry code provisions. Adminstration and enforcement of the urban 
forestry code provisions will be assigned to the Community D evelopment Department. The city's 
comprehensive approach to developing the CPA and DCA, and planned adminstration and enforcement 
by a single department is consistent with this policy. 
"3. The City shall continue to regulate the removal of trees within environmentally sensitive 
lands and on lands subject to natural hazards." 
Trees withill environmentally sensistive lands and lands subject to natural hazards, as defined in Chapter 
18.775, would continue to be subject to the recommended Urban Forestry Plan requirements in Chapter 
18.790.030, as part of the development process. When development is not proposed, trees within 
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environmentally sensistive lands would still be regulated by the provision of Chapter 8.1 0, which are non-
land use regulations and not part of this application. T he D CA in Chapter 18.790.030 would continue to 
regulate the removal o f trees within environmentally sensitive lands and on lands subject to natural 
hazards, consistent with this policy. 
"4. The City shall ensure that street design and land use standards provide ample room for the 
planting of trees and other vegetation, including the use of flexible and incentive based 
development standards." 
The recommended design standards in Chapters 18.61 0 - 18.640, Chapter 18.7 45 and Section 18.790.050, 
require ample room and allow flexible standards and incentives for the planting of trees . Included are 
increased dimensions for tree planting spaces, reduction in parking for planting parking lot trees, flexible 
sidewalk locations for planting street trees and mininmm soil volume standards for parking lo t and street 
trees. Through the D CA, the city will ensure that street design and land use standards provide ample room 
for the planting o f trees, including the use of flexible and incentive based development standards, 
consistent with this policy. 
"5. The City shall require the replacement and/ or installation of new street trees, unless 
demonstrated infeasible, on all new roads or road enhancement projects. Trees should be 
planted within planter strips, or at the back of sidewalks if planter strips are not feasible or 
would prohibit the preservation of existing trees." 
Through the D CA in Chapter 18.745.040 (Vol. II , p . 111), the city will require the replacement and/ or 
installation of new street trees, unless demonstrated infeasible, on all new roads or road enhancem ent 
pro jects that are part o f the listed land use permits. N ew roads or road enhancement projects that do not 
require a land use permit are not part of this application. The existing street design standards in Chapter 
18.81 0 require street trees within planter strips but allow planting in the back o f sidewalk if planter strips 
are not feasible or would prohibit the preservation o f existing trees. Chapter 18.810 is no t reconunended 
for revision as part o f this application. Therefore, the D CA in Chapter 18.745.040 that require new street 
trees and the existing street design standards in Chapter 18.810 that require street trees in planter strips are 
consistent with this policy. 
"6. The City shall establish and enforce regulations to protect the public's investment in trees 
and vegetation located in parks, within right-of-ways, and on other public lands and 
easements." 
The D CA (Vol. II , pp. 3-184) are applicable to trees loca ted in parks, within right of ways and on o ther 
public lands and easem ents as part of the land use permitting process for certain development activities in 
those locations. A dditional provisions pro tect the public's investment in trees located in parks, within right 
of ways and on o ther public lands and easements outside the development process (Vol. III), but are not 
land use regulations and no t part o f this application. The recommended applicability of land use 
regulations pro tect the public's inves tment in trees located in parks, within rights o f ways and on other 
public lands and easements consistent with this policy. 
"7. The City shall conduct an ongoing tree and urban forest enhancement program to improve 
the aesthetic experience, environmental quality, and economic value of Tigard's streets 
and neighborhoods." 
The Urban Forestry Code Revisions Pro ject is part o f the city's ongoing tree and urban fores t 
enhancement program. The D CA 0' ol. II, pp . 3-184) require development to improve the aes thetic 
experience, environmental quality and economic value of Tigard 's streets and neighborhoods through tree 
planting and preservation requirements as part of the land use process, consistent with this policy. 
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"8. The City shall continue to maintain and periodically update approved tree lists for specific 
applications and site conditions, such as street trees, parking lot trees, and trees for 
wetland and riparian areas." 
T he D CA in Chapters 18.61 0 through 18.640, Chapter 18.745 and Section 18.790.050, reference the Urban 
Forestry Manual for a list o f recommended trees for specific applications and site conditions such as street 
trees, parking lot trees and trees for wetland and riparian areas when planting is required as part o f the land 
use process. While the Urban Forestry Manual itself no t part o f this application, referencing the 
recommending trees lists within it during the land use process is consistent with this policy. 
"9. The City shall discourage the use or retention of invasive trees and other plants through 
the development review process." 
T he lists of recommended trees referenced in Goal 2.2 Policy 8 do not inlcude invasive trees . In addtion , a 
nuisance (i.e. invasive) tree list is included in the Urban Forestry Manual and nuisance trees are not eligible 
for credit when planted to meet the Urban Forestry Plan requil:em ents in Section 18.790.030. While the 
Urban Forestry Manual itself no t part of this application, not allowing nuisance trees to m eet the tree 
planting standards that are part o f the development review process dicourages their use and retention and 
is consistent with this policy. 
"10. The City shall require the appropriate use of trees and other vegetation as buffering and 
screening between incompatible uses." 
The D CA retain the ex1stmg buffering and screening requirements for incompatible uses il1 Section 
18.745.050 (Vol. II, p . 117). T he spacing requirements and names o f the specific tree typ es have been 
amended slightly for consistency with the spacing requirements and names o f trees in o ther sections in 
T itle 18. The slightly modified D CA would continue to require appropriate use of trees and other 
vegetation as buffering and screening between incompatible uses and is consistent with this policy. 
"11. The City shall develop and implement a citywide Urban Forestry Management Master 
Plan." 
Council accepted the Urban Forestry Master Plan (Vol. V, p . 207) on N ovember 10, 2009, consistent with 
this policy. T he Urban Forestry Code Revisions Pro ject implements the Comprehensive Plan as 
recommendationed by the Urban Forestry Master Plan. While the Urban Forestry Mas ter Plan is not part 
of this application, is not a land use regulation and does not contain relevant approval criteria for this 
application, its development and implementation has helped shape the Urban Forestry Code Revisions and 
is consistent witl1 this policy. 
"GOAL: 
2.3 To balance the diverse and changing needs of the city through well designed urban 
development that minimizes the loss of existing trees to create a living legacy for future 
generations." 
"POLICIES: 
1. The City shall develop and implement standards and procedures designed to minimize the 
reduction of existing tree cover, with priority given to native trees and non-native varietals 
that are long lived and/ or provide a broad canopy spread." 
T he D CA are designed to minimize the reduction of existing tree cover through tl1e Urban Forestry Plan 
requirements in Section 18.790.030 (Vol. II , p . 139). Section 18.790.030 requires tree canopy cover 
standards to be met as part o f the land use process. The standards for meeting tree canopy cover 
requirements are within the Urban Forestry Manual and are designed to minimize the reduction o f existing 
tree cover by grantil1g bonus credits for preserving existing trees. In addition, standards are designed to 
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give priority to native trees as well as non-native trees that are long-lived and broad spreading because 
these tree typ es will most fa cilitate acheivement o f canopy cover standards. 
T he D CA in Section 18.790.050.C include incentives and flexible standards for the preservation o f 
individual trees (Vol. II , p . 149). T he amendments are designed to minimize the reduction o f existing tree 
cover by allowing lo t size averaging, setback adjustments and parking adjustments. 
In addition, incentives and flexible standards for significant tree groves are recommended in Section 
18.790.050.D, such as density transfer, setback adjustments and additional building height to preserve 
significant tree groves. T hese incentives and flexible standards for significant tree groves are designed to 
minimize the reduction o f existing tree cover while prioritizing native trees that are long-lived and provide 
a broad canopy spread . Flexible standards and incentives for the preserva tion o f signficant tree groves 
were developed through the Goal 5 rule requirements as required by state law. Goal 5 rule requirements 
are no t applicable to the prese1vation and planting o f individual trees because individual trees are planted 
and prese1ved primarily for their aes theitic, air and water quality benefits. 
T herefore, the Urban Forestry Plan requirements in Section 18.790.030 and the incentives and flexible 
standard s for preserva tion in Section 18.790.050 have the effect of minimizing the reduction o f existing 
tree cover, with priority given to native trees and non-native varietals that are long-lived and / or provide a 
broad canopy spread consistent with this policy. 
"2. In prescribing the mitigation of the impacts of development, the City shall give priority to 
the protection of existing trees, taking into consideration the related financial impact of 
mitigation." 
T he D CA prescribe the mmgation of the impacts o f development through Urban Forestry Plan 
requirements in Section 18.790.030 (Vol. II , p . 139). Section 18.790.030 requires tree canopy cover 
standards to be met by planting new trees, preserving existing trees or paying a fee in lieu of planting or 
prese1va tion. The standards are designed to minimize the reduction o f existing tree cover by granting 
bonus credits for preserving existing trees. 
The D CA in Section 18.790.050.C include flexible standards to facilitate the preserva tion o f individual 
trees (Vol. II , p . 149). T he flexible standards include lo t size averaging, setback adjustments and parking 
adjustments. 
In addition, incentives and flexible standards in Section 18.790.050.D would facilitate the preserva tion of 
significant tree groves. T hese incentives and flexible standards inlcude density transfer, setback 
adjustments and additional building height to accomodate the prese1vation o f significant tree groves. 
1\ fee in lieu of planting or preserva tion is recommended and takes into consideration the financial impacts 
o f mitiga tion . As further described in the Tree Canopy Fee Memo (Vol. V, p. 171 ), the tree canopy fee was 
es tablished using a conserva tive es timated value of tree canopy based on appraisal standards developed by 
the International Society o f 1\rboriculture. 
T he peer review results demonstrate that the recom.mended canopy requirements are likely acheivable 
through planting and preserva tion for most development projects (Vol. II , p . 185) . T his further inform ed 
the city's consideration o f related financial impacts o f mitiga tion when developing the recommended fee in 
lieu o f planting or prese1va tion. 
Finally, a discretionary Urban Forest!) ' Plan review option (Vol. II , p 142) is recommended to be allowed 
in lieu o f meeting the Urban Forestq Plan requirements in Section 18.790.030. The discretionary Urban 
Forest!) ' Plan review option would allow an applicant to mitiga te the lack of canopy cover by 
incorporating innova tive, alternate development proposals that provide equivalent environmental benefits 
as trees. 
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The range of options for meeting the recommended Urban Forestry Plan requirements in Section 
18.790.030 prioritize the protection of existing trees. H owever, applicants would be allowed to rmngate 
through acheivable planting requirements, a fee in lieu of planting or preservation or a discretionary review 
option. These recommended alternatives to preservation were developed with consideration of the 
financial impacts of mitigation consistent with this policy. 
"3. The City shall develop policies and procedures designed to protect trees, including root 
systems, selected for preservation during land development." 
The D CA in Section 18.790.030 would require a n·ee preservation and removal site plan by a certified 
arborist or landscape architect (Vol. II , p. 139). The specifications for the tree preservation and removal 
site plan are in the Urban Forestry Manual and would require the certified arborist or landscape architect 
to identify methods for protecting n·ees, including root systems, selected for preservation during land 
development. The requil:ed methods would i11clude, but are not limited to, displaying the type, size and 
location of tree protection fencing to scale on the tree preservation and removal site plan. 
In addition, Section 18.790.060 would require the certified arborist or landscape architect to perform 
regular i11spections of the tree protection fencing and o ther tree protection methods throughout the land 
development process (Vol. II, p. 163). The recommended D evelopment Code requirements for a tree 
preservation and removal site plan along with regular i11spections and reporting on that plan during the 
development process are designed to protect n·ees, including their root systems, consistent with this policy. 
"4. The City shall address public safety concerns by ensuring ways to prevent and resolve 
verified tree related hazards in a timely manner." 
The D CA allow tree removal if the certified arborist or landscape architect determines a tree has become a 
hazard during the development process (Vol. II, p . 169). The ratil1g system for determining tree hazards is 
within the Urban Forestry Manual and cross-referenced by the recommended code amendments. 
Therefore, the D CA ensure the prevention and resolution of verified tree related hazards during the land 
development process, consistent with this policy. 
Additional provisions in Chapter 8.06 in Volume III would prohibit verified tree related hazards and allow 
for their emergency abatement, however these provisions are not land use regulations and not part of this 
application. 
"5. The City shall develop and enforce site design and landscape requirements to reduce the 
aesthetic and environmental impacts of impervious surfaces through the use of trees and 
other vegetation." 
The D CA in Chapter 18.7 45 (Vol. II , p . 1 07) would require the planting of street trees and parking lot 
trees as part of the land use process. Street trees would be required based on the amount of street frontage 
of the development and parking lot trees would be required to provide 30% minimum tree canopy cover 
at maturity over the parking area. These recommended site design and landscape requirements were 
developed and would be enforced to reduce to the aesthetic and environmental ilnpacts of ilnpervious 
surfaces, consistent with this policy. 
"6. The City shall, in order to preserve existing trees and ensure new trees will thrive, allow 
and encourage flexibility in site design through all aspects of development review." 
The D CA in Section 18. 790.050.C (Vol. II , p. 149) would allow and encourage flexibility in site design for 
the preservation and planting of individual trees. These flexible site design standards include lot size 
averaging, setback adjustments and parking adjustments. 
In addition, flexibility in site design standards are allowed and encouraged for the preservation significant 
tree groves by the D CA in Section 18. 790.050.D. These flexible site design standards include density 
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transfer, setback adjustments and additional building height. 
T herefore, the D CA in Section 18. 790.050.C and 18. 790.050.D include flexible site design standards that 
would allow and encourage flexibility to preserve existing trees and ensure new trees will thrive consistent 
with this policy. 
"7. The City shall require all development, including City projects, to prepare and implement 
a tree preservation and landscaping plan, with the chosen trees and other plant materials 
appropriate for site conditions." 
The D CA in Chapters 18.745 (Vol. II, p . 107) and 18.790 (Vol. II , p. 135), would require tree preserva tion 
and landscaping plans that are appropriate to site conditions. These requirements are applicable to city 
projects. 
The term " development" is so broad that any material change to a property, such as installing a shed, 
could fall within the definition . Staff and the Citizen Advisory Committee discussed the scale o f 
development that should be required to in1plement tree preservation and landscaping plans. It was 
determined that those land use permit types listed in Chapters 18.745 and 18.790 are of appropriate scale 
that requiring tree preserva tion and landscaping plans would be roughly proportional to the impacts o f 
development. A fter evaluating smaller scale projects, such as shed installations or residential additions, it 
was determined they are usually designed in ways that have minimal impacts on trees and surrounding 
neighborhoods. 
T herefore, the D CA would require appropriate tree preservation and landscaping plans for all development 
with significant impacts, including city projects, consistent with this policy. 
"8. The City shall continue to cooperate with property owners, businesses, other jurisdictions, 
agencies, utilities, and non-governmental entities to manage and preserve street trees, 
wetlands, stream corridors, riparian areas, tree groves, specimen and heritage trees, and 
other vegetation." 
As described in the Process Summary (Vol. I, p . 26), the city cooperated with property owners, businesses, 
o ther jurisdictions, agencies, utilities and non-governmental entities in developing code amendments as 
part of the Urban Fores try Code Revisions Project. The D CA in Chapter 18.745.040 (Vol. II , p. 111) 
contribute to the management and preserva tion o f street trees during the land use process. 
T he D CA in Section 18. 790.050.D (Vol. II , p . 153) contribute to the preserva tion significant tree groves 
during the land use process. Flexible site design standards for the preserva tion o f signficant tree groves 
were developed through the Goal 5 rule requirements, as required by state law. 
Individual specimen and heritage trees would be required to be included as part of the Urban Forestry 
Plan through the recommended amendments in Section 18.790.030 (Vol. II , p. 139). Including specimen 
and heritage trees in the Urban Forestry Plan will contribute to their preserva tion and management 
because they could be considered and utilized to meet plan requirements. 
T he D CA do no t affect the preserva tion and management o f wetlands, stream corridors and riparian areas 
except to the extent that trees preservation and planting activities may overlap with these areas. H owever, 
the D CA are intended to support the preserva tion and management o f trees and significant trees groves, 
no t wetlands, stream corridors and riparian areas. 
T he D CA were developed in cooperation with property owners, businesses, o ther jurisdictions, agencies, 
utilities and non-governmental entities . T he D CA support the management and preserva tion o f stree t 
trees, significant tree groves, specimen and heritage trees during the development process . The D CA were 
no t specifically designed to affect the management or preserva tion of wetlands, stream corridors or 
riparian areas. Therefore, the D CA are consistent with this policy. 
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"9. The City shall require, as appropriate, tree preservation strategies that prioritize the 
retention of trees in cohesive and viable stands and groves instead of isolated specimens." 
The CPA establishes an overlay district for 70 significant tree groves covering 527 acres . The 
recommended flexible standards and incentives in Section 18. 790.050.D (Vol. II , p. 153) include allowed 
reduction in minimum density, density transfer, increased building height, reduced setbacks, adjustments 
to Urban Forestry Plan requirements and adjustments to street and utility standards. The recommended 
flexible standards and incentives would facilitate the prese1vation of the significant tree groves in cohesive 
and viable stands instead of isolated specimens consistent with this policy. 
"10. Applications for tree removal and tree management plans shall be reviewed by a certified 
arborist employed or under contract to the City." 
The D CA in Section 18.790.030 would require urban forestry plans to be coordinated, reviewed and 
approved by a certified arborist or landscape architect (Vol. II, p. 139). The city currently employs a 
certified arborist to review land use permit applications to determine whether urban forestry related 
requirements are met. The requirement for urban foresuy plans to be coordinated, reviewed and approved 
by a certified arborist or landcape architect and the city's current practice for land use applications to be 
reviewed by a certifed arborist employed by the city, is consistent with this policy. 
"11. The City shall recognize the rights of individuals to manage their residential landscapes." 
The DCA in Chapter 18.790 (Vol. II, p. 135) would allow applicants to meet Urban Fores try Plan 
requirements through any combination of prese1v ing existing trees, planting new trees or paying a fee in 
lieu of planting or preservation. In addition, a discretiona1y review process in Section 18.790.040 (Vol. II, 
p. 143) is available as an alternative to providing the requil·ed trees. Finally, Section 18.790.070 would allow 
individuals to modify their Urban Foresuy Plan after the land use approval process to provide additional 
flexibility to adapt to changing site conditions or personal preferences. Therefore, the DCA in Chapter 
18.790 recognize the rights of individuals to manage their residential landscapes, consistent with this 
policy. 
Title 8 amendments include tree permit procedures in Chapter 8.04 of Volume III that allow for increased 
flexibility for tree management activities outside the land use process . H owever, amendments to Title 8 are 
not land use regulations and are not part of this application. 
NATURAL RESOURCES 
"GOAL: 
5.1: Protect natural resources and the environmental and ecological functions they provide 
and, to the extent feasible, restore natural resources to create naturally functioning systems 
and high levels of biodiversity." 
"POLICIES: 
1. The City shall protect and, to the extent feasible, restore natural resources in a variety of 
methods to: 
A. contribute to the City's scenic quality and its unique sense of place; 
B. provide educational opportunities, recreational amenities, and buffering 
between differential land uses; 
C. maximize natural resource functions and services including fish and 
wildlife habitat and water quality; and 
D . result in healthy and naturally functioning systems containing a high 
level of biodiversity." 
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T he recommended Comprehensive Plan amendment es tablishes an overlay district for 70 significant tree 
groves covering 527 acres. As further explained in th~ Tree Grove ESEE Analysis 01 ol. II , p . 219), key 
evaluation criteria in the inventory and selection of significant tree groves were grove maturity/ tree size, 
grove size, health / viability, visibility, screening and buffering, accessibility, rarity, educational/ recreational 
potential, wildlife habitat value and connectivity and the amount of existing disturbance. The analyses and 
conclusions found in the Statewide Planning Goal Analysis section of the Tigard Goal 5 ESEE Analysis 
for Significant Tree G roves (page 3-4 through 3-58) explains how the city adhered to the Goal 5 process 
and meets the applicable criteria. Those analyses and conclusions are hereby explicitly incorporated into 
the findings o f this staff report. 
T he DCA in Section 18.790.050.D (Vol. II, p. 153) include regulatory incentives and flexible standards that 
allow for the preserva tion of significant tree groves. 
T he evaluation criteria used for the inventory and selection o f significant tree groves and the 
recommended regulatory incentives and flexible standards support this policy by allowing for the 
maximum preserva tion of the functions and values o f significant tree groves with the attributes identified 
in this policy. 
"4. The City shall actively coordinate and consult with landowners, local stakeholders, and 
g overnmental jurisdictions and agencies regarding the inventory, protection, and 
restoration of natural resources." 
As more fully described in the Tree Grove ESEE analysis 01 ol. II, p . 219), the city actively coordinated 
and consulted with landowners, local stakeholders, governmental jurisdictions and agencies throughout the 
development of the CPA and D CA. The analyses and conclusions found in the Statewide Planning Goal 
A nalysis section of the Tigard Goal 5 ESEE Analysis for Significant Tree G roves (page 3-4 through 3-58) 
explains how the city adhered to the Goal 5 process and meets the applicable criteria. Those analyses and 
conclusions are hereby explicitly incorporated into the findings of this staff report. 
During the inventory phase, all property owners with an inventoried tree grove on their property were 
provided notice, compliant with Goal 5 rule requirements. As part of the notice, property owners were 
invited to a tree grove open house, which was held on October 6, 2010, to learn more and provide 
feedback about the process. 
After developing draft regulatory incentives and flexible standards based on community input, property 
owners and the community were invited to a second tree grove open house on February 17, 2011, to learn 
more and provide feedback on the recommended regulatory incentives and flexible standards. 
In addition, the city coordinated with local stakeholders and governmental jurisdictions and agencies as 
part of the Citizen Advisory Committee and Technical Advisory Committee processes, which are more 
fully described in the Process Summary 01 ol. I, p . 26). Both the Citizen Advisory Committee and 
Technical Advisoty Committee reviewed and approved the recommended regulatoty incentives program 
for significant tree groves. T he Citizen Advisory Committee approval is documented in their guiding 
principles for the Tree Grove Preservation Incentives (Vol. V, p . 143). 
T herefore, the city coordinated and consulted with landowners, local stakeholders, governmental 
jurisdiction and agencies during the inven taty and development of regulatory incentives and flexible 
standards for preserving significant tree groves, consistent with this policy. 
"5. The City shall utilize p eriodic assessm ents of the effectiveness of the City's program s and 
regulatory structures to g uide future decisions regarding natural resource protection , 
m anagem ent, and restoration." 
T he city utilized periodic canopy assessments as part of the Urban Forestty Master Plan process. The 
periodic canopy assessments demonstrated a 24% decline in canopy clusters of over 5 acres in size from 
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1996 to 2007. These and other findings were used to develop recommendations in the Urban Forestry 
Master Plan (Vol. V, p. 207) that helped guide the CPA and DCA. The city identified 70 significant tree 
groves through the statewide Goal 5 planning process as further explained in the Tree Grove ESEE 
Analysis (Vol. II, p. 219). The analyses and conclusions found in the Statewide Planning Goal Analysis 
section of the Tigard Goal 5 ESEE Analysis for Significant Tree Groves (page 3-4 through 3-58) explains 
how the city adhered to the Goal 5 process and meets the applicable criteria. Those analyses and 
conclusions are hereby explicitly incorporated into the findings of this staff report. Therefore, periodic 
assessments of the effectiveness of the city's programs and regulatory structures were used to guide the 
CPA and DCA aimed at the protection, management and restoration of significant tree groves, consistent 
with this policy. 
"6. The City shall utilize incentives or disincentives, to the extent feasible, to discourage 
property owners from removing or degrading natural resources prior to application for 
development or annexation." 
The city identified 70 significant tree groves through the statewide Goal 5 planning process as further 
explained in the Tree Grove ESEE Analysis (Vol. II, p. 219). The analyses and conclusions found in the 
Statewide Planning Goal Analysis section of the Tigard Goal 5 ESEE Analysis for Significant Tree Groves 
(page 3-4 through 3-58) explains how the city adhered to the Goal 5 process and meets the applicable 
criteria. Those analyses and conclusions are hereby explicitly incorporated into the findings of this staff 
report. The development code amendments in Section 18. 790.050.D (Vol. II, p. 153) include regulatory 
incentives and flexible standards to facilitate the preservation of significant tree groves. Regulatory 
incentives and flexible standards include allowed reduction in minimum density, density transfer, increased 
building height, reduced setbacks, adjustments to Urban Forestry Plan requirements and adjustments to 
street and utility standards. The regulatory incentives and flexible standards are voluntary, and thus there is 
no incentive for property owners to remove or degrade significant trees groves prior to application for 
development or annexation. Therefore, the DCA in Section 18. 790.050.D are consistent with this policy. 
"7. The City shall protect and restore riparian and upland habitats to the maximum extent 
feasible on public and private lands." 
The city identified 70 significant tree groves through the statewide Goal 5 planning process as further 
explained in the Tree Grove ESEE Analysis (Vol. II, p. 219). The analyses and conclusions found in the 
Statewide Planning Goal Analysis section of the Tigard Goal 5 ESEE Analysis for Significant Tree Groves 
(page 3-4 through 3-58) explains how the city adhered to the Goal 5 process and meets tl1e applicable 
criteria. Those analyses and conclusions are hereby explicitly incorporated into the findings of this staff 
report. The CPA and DCA facilitate the preservation of significant tree groves located in both riparian and 
upland habitats and on public and private lands. The city also has non-regulatory programs to protect and 
restore riparian and upland habitats, but these are not land use regulations and not part of this application. 
Therefore, the CPA and DCA facilitate the preservation of significant tree groves in both riparian and 
upland habitats on both public and private property, which allows for their further protection and 
restoration through non-regulatory programs consistent with this policy. 
"10. The City shall complete a baseline inventory of significant natural resources and update or 
improve it as necessary, such as at the time of Comprehensive Plan Periodic Review, 
changes to Metro or State programs, or to reflect changed conditions, circumstances, and 
community values." 
The city completed a baseline inventory of 70 significant tree groves in compliance with Statewide 
Planning Goal 5 rule requirements as further detailed in the Tree Grove ESEE Analysis (Vol. II, p. 219). 
The analyses and conclusions found in the Statewide Planning Goal Analysis section of the Tigard Goal 5 
ESEE Analysis for Significant Tree Groves (page 3-4 through 3-58) explains how the city adhered to tl1e 
Goal 5 process and meets the applicable criteria. Those analyses and conclusions are hereby explicitly 
incorporated into the findings of this staff report. The significant tree grove map (Exhibit A) represents 
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the baseline inventory, which will be adopted through the CPA and updated and improved as necessary 
consistent with this policy. 
"11. The City shall assist landowners in the protection of natural resources through diverse 
methods including , but not limited to : education, incentives, planned development 
standards and regulations, and conservation easements." 
T he city identified 70 significant tree groves through the statewide Goal 5 planning process as further 
explained in the Tree Grove ESEE Analysis 0 ' ol. II, p. 219) . The analyses and conclusions found in the 
Statewide Planning Goal Analysis section of the Tigard Goal 5 ESEE Analysis for Significant Tree Groves 
(page 3-4 through 3-58) explains how the city adhered to the Goal 5 process and meets the applicable 
criteria. Those analyses and conclusions are hereby explicitly incorporated into the findings of this staff 
report. The DCA in Section 18.790.050.D include regulatory incentives and flexible standards to assist 
landowners in the preservation of significant tree groves 0'ol. II, p . 153). Regulatory incentives and 
flexible standards include allowed reduction in minimum density, density transfer, increased building 
height, reduced setbacks, adjustments to Urban Fores try Plan requirements and adjustments to street and 
utility standards. Permanent protection of significant tree groves through instruments such as conservation 
easements would be required to utilize the incentives and flexible standards. T hese incentives and flexible 
standards would assist landowners in the protection of natural resources consistent with this policy. 
"12. The City shall develop and implem ent standards and procedures that mitigate the loss of 
natural resource functions and services, with priority given to protection over mitigation." 
T he city identified 70 significant tree groves through the statewide Goal 5 planning process as further 
explained in the T ree G rove ESEE Analysis 0' ol. II , p . 219). The analyses and conclusions found in the 
Statewide Planning Goal Analysis section o f the Tigard Goal 5 ESEE Analysis for Significant Tree Groves 
(page 3-4 through 3-58) explains how the city adhered to the Goal 5 process and meets the applicable 
criteria. Those analyses and conclusions are hereby explicitly incorpora ted into the findings of this staff 
report. The D CA in Section 18.790.050.D include regulatory incentives and flexible standards to prioritize 
the preservation of significant tree groves over mitigation. In utilizing these regulatory incentives and 
flexible standards, applicants would be required to preserve at least 10,000 square feet of significant tree 
grove canopy and to maximize the connectivity and viability of the remaining portion o f the significant 
tree grove under the direction of a certified arborist or landscape architect 0 1ol. II , p . 153). Considerations 
in the Urban Forestry Manual are cross-referenced in Section 18.790.050.D to provide additional guidance 
for the certified arborist or landscape architect in the preservation of a connected and viable significant 
tree grove. Therefore, the D CA in Section 18.790.050.D create standards and procedures that mitigate the 
loss of natural resource functions and services, with priority given to pro tection of significant tree groves 
over mitigation, consistent with this policy. 
13. "The City shall identify, preserve, and create linkages between wildlife habitat areas, to the 
extent feasible, as a key component of p arks, open sp ace, and surface water m anagem ent 
plans." 
As further explained in the Tree Grove ESEE Analysis 0' ol. II, p. 232), the city identified 70 significant 
tree groves using wildlife habitat functions, connectivity and diversity as key criteria. The analyses and 
conclusions found in the Statewide Planning Goal Analysis section of the Tigard Goal 5 ESEE Analysis 
for Significant Tree Groves (page 3-4 through 3-58) explains how the city adhered to the Goal 5 process 
and meets the applicable criteria. T hose analyses and conclusions are hereby explicitly incorporated into 
the findings of this staff report. The D CA in Section 18.790.050.D include regulatory incentives and 
flexible standards to preserve significant tree groves 0' ol II, p. 153). In utilizing these regulatory incentives 
and flexible standards applicants would be required to maximize the connectivity of the remaining portion 
of the significant tree grove under the direction of a certified arborist or landscape architect. 
Considerations in the Urban Forestry Manual are cross-referenced in Section 18.790.050.D to provide 
additional guidance for the certified arborist or landscape architect in the preservation of a connected 
significant tree grove. Identified significant tree groves overlap parks, open spaces and surface water 
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management plan areas. Significant tree groves may be preserved to create linkages between wildlife 
habitats areas when plans are updated for these areas, consistent with this policy. However, this application 
is not intended as an update to any parks, open space or surface water management plan. 
ENVIRONMENTAL QUALITY 
"GOAL: 
6.1 Reduce air pollution and improve air quality in the community and region." 
"POLICIES: 
6. The City shall encourage the maintenance and improvement of open spaces, natural 
resources, and the City's tree canopy to sustain their positive contribution to air quality." 
The DCA in Section 18.790.050.D include regulatory incentives and flexible standards to encourage the 
maintenance and in1provement of significant tree groves 01 ol. II, p. 153). In addition, the DCA in Section 
18.790.030 require the achievement of tree canopy through planting, preservation or a fee in lieu to 
support the city's urban forestry program 01 ol. II, p. 139). One benefit of these DCA is that d1ey 
encourage the maintenance and improvement of tree canopy citywide, as further detailed in the Tree 
Values Memo 0 ' ol. V, p. 149), which is well documented to have a positive contribution to air quality, 
consis tent with this policy. 
"GOAL: 
6.2 Ensure land use activities protect and enhance the community's water quality." 
"POLICIES: 
3. The City shall encourage the use of low impact development practices that reduce 
stormwater impacts from new and existing development." 
The discretionary Urban Forestry Plan review 01 ol. II, p. 143) allows the use of techniques that minimize 
hydrological impacts such as those detailed in Clean Water Services Low Impact D evelopment 
Approached (LIDA) Handbook as an alternative to meeting the clear and objective Urban Forestry Plan 
requirements in Section 18.790.030 0 ' ol. II, p. 139). Therefore, the discretionary Urban Forestry Plan 
review option encourages the use of low impact development practices that reduce stormwater impacts 
from new and existing development, consistent with this policy. 
"4. The City shall protect, restore, and enhance, to the extent practical, the natural functions 
of stream corridors, trees, and water resources for their positive contribution to water 
quality." 
The DCA in Section 18. 790.050.D 01 ol. II, p. 153) include regulatory incentives and flexible standards to 
encourage the maintenance and improvement of significant tree groves. In addition, the D CA in Section 
18.790.030 require the achievement of tree canopy through planting, preservation or a fee in lieu to 
support the city's urban forestry program 01 ol. II, p. 139). These D CA protect, res tore and enhance d1e 
natural functions of trees, which have a positive contribution to water quality, as evidenced by the Tree 
Values Memo 01ol. V, p. 149), consistent with this policy. 
HAZARDS 
"GOAL: 
7.1 Protect people and property from flood, landslide, earthquake, wildfire, and severe weather 
hazards." 
"POLICIES: 
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10. The City shall work with Clean Water Services to protect natural drainageways and 
wetlands as valuable water retention areas and, where possible, find ways to restore and 
enhance these areas." 
As described in the Process Summary 01 ol. I, p. 26), the city included Clean Water Setv ices as a member 
o f the Technical Advisory Committee for the Urban Forestry Code Revisions Project. T he main purpose 
o f Clean Water Services participation was to ensure the CPA and D CA in this application do not conflict 
with o ther standards that protect natural drainage ways and wetlands. T he city and Clean Water Services 
determined that the standards are not in conflict. Therefore, the CPA and D CA are consistent with this 
policy. 
"13. The City shall retain and restore existing vegetation with non-invasive species in areas 
with landslide potential to the greatest extent possible." 
As further explained in the Tree Grove E SEE Analysis, the city identified 70 significant tree groves using 
the presence o f non-invasive species as a key criterion 01 ol. II, p . 231 ). The analyses and conclusions 
found in the Statewide Planning Goal Analysis section o f the Tigard Goal 5 E SEE Analysis for Significant 
Tree Groves (page 3-4 through 3-58) explains how the city adhered to the Goal 5 process and meets the 
applicable criteria. T hose analyses and conclusions are hereby explicitly incorporated into the findings o f 
this staff report. T he significant tree grove map (Exhibit A) identifies the location of these 70 significant 
tree groves, many of which overlap areas with landslide potential. The D CA in Section 18.790.050. include 
regula tory incentives and flexible standards to retain significant tree groves (Vol. II , p . 153). 
In addition, the D CA in Section 18.790.030 require the achievement o f tree canopy through planting, 
preserva tion or a fee in lieu to support the city's urban forestry program (Vol. II, p . 139). In meeting tree 
canopy standards, nuisance (i.e. invasive) trees are prohibited from planting by the Urban Forestry Manual. 
T hese standards support this policy by encouraging the presetv ation o f significant tree groves with non-
invasive species and prohibiting the planting o f invasive tree species including within areas with landslide 
po tential. 
PARKS, RECREATION, TRAILS, AND OPEN SPACE 
"GOAL: 
8.1 Provide a wide variety of high quality park and open spaces for all residents, 
including both: 
A. developed areas with facilities for active recreation; and 
B. undeveloped areas for nature-oriented recreation and the protection 
and enhancement of valuable natural resources within the parks and 
open space system." 
"POLICIES: ... 
2. The City shall preserve and, where appropriate, acquire and improve natural areas located 
within a half mile of every Tigard resident to provide passive recreational opportunities." 
As further explained in the Tree G rove ESEE Analysis, the city identified 70 significant tree groves using 
visibility, accessibility and educational/ recrea tional potential as key criteria (Vol. II , p . 232). The analyses 
and conclusions found in the Statewide Planning Goal r\nalysis section o f the Tigard Goal 5 ESEE 
r\nalysis for Significant Tree G roves (page 3-4 through 3-58) explains how the city adhered to the Goal 5 
process and meets the applicable criteria. Those analyses and conclusions are hereby explicitly 
incorporated into the ftndings o f this staff report. T he significant tree grove map (Exhibit A) identifies the 
location of these 70 significant tree groves, which are distributed citywide. T he D CA in Section 
18.790.050.D include regulatory incentives and flexible standards to retain significant tree groves (Vol. II , 
p. 153). These CPA and D CA support this policy by contributing to the preserva tion o f visible, accessible 
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and potentially educational/ recreational natural areas located within a half mile of every Tigard resident to 
provide passive recreational opportunities . 
"16. The City shall continue to encourage and recognize the important role of volunteers and 
community groups in meeting City park, trail, open space, and recreation needs, and in 
building stewardship and promoting community pride." 
The Process Summary details the Citizen Advisory Committee's role in providing recommendations to 
staff during the development of the CPA and D CA 01 ol. I, p. 26). The Citizen Advisory Committee 
included representation from the Parks and Recreation Advisory Board to allow community interests 
relating to parks, trails, open spaces, and recreational needs to be well represented throughout the process. 
The CPA creating a significant tree grove map (Exhibit A) and the D CA in Title 18 are applicable to 
certain development actions within parks, trails, open spaces and recreational areas. Inclusion of a Parks 
and Recreation Advisory Board member on the Citizen Advisory Committee is supportive of this policy in 
that encouraged and recognized the important role o f volunteers and community groups in meeting city 
park, trail, open space and recreational needs, and in building stewardship and promoting community 
pride. 
"17. The City shall maintain and manage its parks and open space resources in ways that 
preserve, protect, and restore Tigard's natural resources, including rare, or state and 
federally listed species, and provide "Nature in the City" opportunities." 
As further explained in the Tree Grove E SEE Analysis, the city identified 70 significant tree groves using 
wildlife habitat value and connectivity as a key criterion 01 ol. II, p. 232). The analyses and conclusions 
found in the Statewide Planning Goal Analysis section of the Tigard Goal 5 ESEE Analysis for Significant 
Tree Groves (page 3-4 through 3-58) explains how the city adhered to the Goal 5 process and meets the 
applicable criteria. Those analyses and conclusions are hereby explicitly incorporated into the findings of 
this staff report. The significant tree grove map (Exhibit A) identifies the location of these 70 significant 
tree groves, many of which overlap with city's park and open space resources. The DCA in Section 
18.790.050.D include regulatory incentives and flexible standards to preserve significant tree groves 01ol. 
II, p. 153). In utilizing these regulatory incentives and flexible standards, applicants are required to 
maximize the connectivity of the remaining portion of the significant tree grove under the direction of a 
certified arborist or landscape architect. While rare, state and federally listed species were not specifically 
inventoried as part this process, the preservation of significant tree groves is supportive of their 
preservation. Therefore, this policy of maintaining and managing park and open space resources in ways 
that preserve, pro tect and res tore Tigard's natural resources (including rare or state and federally listed 
species) and providing "Nature in the City" opportunities, is supported by the CPA and D CA aimed at the 
preservation of significant tree groves. 
"19. The City shall seek to establish and manage a fully functional urban forest." 
The Urban Forestry Master Plan 01 ol. V, p. 207) provides recommendations for es tablishing and 
managing a fully functional urban forest. The recommendations require CPA and D CA to implement the 
goals and policies in the Urban Forest section of the Comprehensive Plan. The CPA and D CA are 
consistent with the recommendations in the Urban Forestry Master Plan . Therefore, the city is seeking to 
contribute to the establishment and management of a fully functional urban forest with this application, 
consistent with this policy. 
ECONOMIC DEVELOPMENT 
"GOAL: 
9.1 Develop and maintain a strong, diversified, and sustainable local economy." 
"POLICIES: 
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3. The City's land use and other regulatory practices shall be flexible and adaptive to 
promote economic development opportunities, provided that required infrastructure is 
made available." 
The CPA and D CA in Section 18. 790.050.D include regulatory incentives and flexible standards to retain 
significant tree groves (Vol. II , p . 153). In addition, the D CA in Section 18.790.030 require the 
achievement o f tree canopy through planting, preserva tion or a fee in lieu to support the city's urban 
fores try program 0' ol. II , p. 139) . Therefore, the CPA and D CA have been designed to be flexible and 
adaptive to promote economic development opportunities and allow the provision o f required 
infras tructure, consistent with this policy, while concurrently supporting the city's urban forestry goals and 
policies . 
"GOAL: 
9.3 Make Tigard a prosperous and desirable place to live and do business ." 
"POLICIES: 
2. The City shall adopt land use regulations and standards to ensure a well-designed and 
attractive urban environment that supports/protects public and private sector 
investments ." 
During the Urban Forestry Mas ter Plan process the community identified the urban fores t as a key 
component o f a well-designed and attractive urban environment (Vol. V, p . 207). T he CPA and D Ci\ 
would create land use regulations and standards that incorporate trees and significant tree groves within 
the urban environment to support and pro tect public and private sector inves tments consistent with this 
policy. 
"3. The City shall commit to improving and maintaining the quality of community life (public 
safety, education, transportation, community design, housing, parks and recreation, etc.) 
to promote a vibrant and sustainable economy." 
During the Urban Fores try Mas ter Plan process, the community identified the urban fores t as a key 
component to in1proving and maintaining quality o f community life (Vol. V, p . 207). In addition, the Tree 
Values Memo describes the ability of trees to promote a vibrant and sustainable economy (Vol. V, p. 149). 
The CPA and D CA would create land use regulations and standards that incorporate trees and significant 
tree groves within the urban environment to improve and maintain the quality o f community life and to 
promote a vibrant and sustainable econom y consistent with this policy. 
HOUSING 
"GOAL: 
10.1: Provide opportunities for a variety of housing types to meet the diverse housing needs of 
current and future City residents." 
"POLICIES: 
1. The City shall adopt and maintain land use policies, codes, and standards that provide 
opportunities to develop a variety of housing types that meet the needs, preferences, and 
financial capabilities of Tigard's present and future residents." 
Tigard 's current policies, codes and standards provide opporturutles for a variety o f housing types, 
including single- family and multi-family housing on land zoned R-1 to R-40 as well as mi'<ed use and 
variations through the planned development overlay. As further explained in the Tree G rove ESEE 
Analysis (Vol. II , p . 21 9), the city identified 70 significant tree groves tlu·ough the statewide Goal 5 
planning process. T he analyses and conclusions found in the Statewide Planning Goal Analysis section o f 
the Tigard Goal 5 ESEE Analysis for Significant Tree G roves (page 3-4 through 3-58) explains how the 
city adhered to the Goal 5 process and meets the applicable criteria. T hose analyses and conclusions arc 
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hereby explicitly incorporated into the findings o f this staff report. The significant tree grove map (Exhibit 
A) identifies the location of these 70 significant tree groves, many of which exist within lands zoned for 
residential uses. The D CA in Section 18.790.050.D include regulatory incentives and flexible standards that 
allow variation in housing types such as attached units to retain significant tree groves (Vol. II , p. 153). 
In addition, the D CA in Section 18.790.030 would require the achievement of tree canopy through 
planting, preservation or a fee in lieu to support the city's urban forestry program (Vol. II. P . 139). 
These CPA and D CA have been designed to be flexible and adaptive to continue to allow a variety of 
housing types, while concurrently supporting the city's urban forestry goals and policies . The D CA (pp. 3-
184) continue to allow opportunities to develop a variety o f housing types that meet the needs, preferences 
and financial capabilities o f Tigard 's present and futw:e residents consistent with this policy. 
"GOAL: 
10.2 Maintain a high level of residential livability." 
"POLICIES: 
1. The City shall adopt measures to protect and enhance the quality and integrity of its 
residential neighborhoods." 
During the Urban Forestry Master Plan process, the community identified the urban forest as a key 
component of the quality and integrity of the city's residential neighborhoods (Vol. V, p. 207) . In addition, 
the Tree Values Memo describes the aesthetic, economic and social contribution of trees to residential 
neighborhoods (Vol. V, p. 149). T he CPA and D CA would create measures to protect and enhance the 
quality and integrity o f the city's residential neighborhoods, consistent with this policy, by incorporating 
trees and significant tree groves. 
"3. The City shall commit to improving and maintaining the quality of community life public 
safety, education, transportation, community design; a strong economy, parks and 
recreation, etc.) as the basis for sustaining a high-quality residential environment." 
During the Urban Forestry Master Plan process the community identified the urban forest as a key 
component of a high-quality residential environment (Vol. V, p . 207). In addition, the T ree Values Memo 
describes the positive contribution of trees to community life, public sa fety, education, transportation, 
community design, a strong economy, parks and recreation (Vol. V, p. 149) . The CPA and D CA would 
incorporate trees and significant tree groves into residential, commercial, industrial and institutional 
environments, as well as the transportation system to maximize the benefits they provide. Therefore, the 
CPA and D CA will have the effect o f improving and maintaining the quality o f community life and 
thereby sustaining a high quality residential environment, consistent with this policy. 
"5. The City shall encourage housing that supports sustainable development patterns by 
promoting the efficient use of land, conservation of natural resources, easy access to public 
transit and other efficient modes of transportation, easy access to services and parks, 
resource efficient design and construction, and the use of renewable energy resources." 
The D CA in Section 18.790.050.D encourage sustainable development patterns that conserve natural 
resources through regulatory incentives and flexible standards that allow the preservation o f significant 
tree groves (Vol. II, p. 153). T hese regulatory incentives and flexible standards would promote the efficient 
use of land by allowing reduction in minimum density, density transfer, increased building height, reduced 
setbacks, adjustments to Urban Forestry Plan requirements and adjustments to street and utility standards. 
In addition, the discretiona1y Urban Fores t1y Plan review option (Vol. II , p. 143) promotes the use of 
renewable energy sources by allowing onsite energy production such as solar technologies as an alternative 
to meeting the clear and objective Urban Forestry Plan requirements in Section 18.790.030 (Vol. II, p. 
139). 
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These D CA would support sustainable development patterns by promoting the efficient use o f land, 
conservation o f natural resources and the use o f renewable energy sources, consistent with this policy. 
"7. The City shall ensure that residential densities are appropriately related to locational 
characteristics and site conditions such as the presence of natural hazards and natural 
resources, availability of public facilitie s and services, and existing land use patterns ." 
As further explained in the Tree Grove E SEE Analysis, the city identified 70 significant tree groves 
through the statewide Goal 5 planning process (Vol. II , p. 21 9). T~e analyses and conclusions found in th e 
Statewide Planning Goal Analysis section of the Tigard Goal 5 E SEE Analysis for Significant Tree Groves 
(page 3-4 through 3-58) explains how the city adhered to the Goal 5 process and meets the applicable 
criteria . T hose analyses and conclusions are hereby explicitly incorporated into the findings o f this staff 
report. The significant tree grove map (Exhibit A) identifies the location o f these 70 significant tree groves, 
many o f which exist witlun lands zoned for residential uses. The D CA in Section 18.790.050.D would 
allow reduction in minimum density as one of the methods to preserve sigtuficant tree groves in residential 
areas (Vol. II, p . 153). T herefore, the CPA and D CA support this policy by ensuring residential densities 
are appropriately related to locational characteristics and site conditions such as the presence of natural 
resources. 
"8. The City shall require measures to mitigate the adverse impacts from differing, or more 
intense, land uses on residential living environments, such as: A) orderly transitions from 
one residential density to another and B) protection of existing vegetation, natural 
resources and provision of open space areas." 
As further explained in the Tree G rove E SEE Analysis , the city identified 70 significant tree groves using 
screet1ing/ buffering ability as a key criterion (Vol. II, p . 231 ). T he analyses and conclusions found in the 
Statewide Planning Goal .Analysis section o f the Tigard Goal 5 E SEE Analysis for Significant Tree G roves 
(page 3-4 through 3-58) explains how the city adhered to the Goal 5 process and meets the applicable 
criteria. Those analyses and conclusions are hereby explicitly incorporated into the findings o f this staff 
report.T he significant tree grove map (Exhibit A) identifies the location o f these 70 significant tree groves, 
many o f which exist within lands zones for residential uses. The D CA in Section 18.790.050.D include 
regulatory incentives and flexible standards to retain significant tree groves (Vol. II, p. 153). Regulatory 
incentives and flexible standards include allowed reduction in nunimum density, density transfer, increased 
building height, reduced setbacks, adjustments to Urban Forestry Plan requiren"lents and adjustments to 
street and utility standards. In the density transfer option, compatibili ty with adjacent development with 
the same or lower density zoning would be ensured by res tricting lo t size reductions to 75 percent or 
grea ter o f the base residential zoning district. Also, when additional building height is allowed, applicable 
buffering and screetung requirements would still apply 
In addition, the D CA in Section 18.7 45.050 (Vol. II , p . 149) continue to require buffering and screening 
with only slight adjustments to tree spacing requirements to ensure consistency with tree spacing 
requirements in o ther chapters. 
Therefore, the CPA and D CA would require measures to mitigate the adverse impacts from differing, or 
more intense, land uses on residential living environments by ensuring orderly transitions from one 
residential density to ano ther and protecting existing vegetation, natural resources and open space areas 
consistent with this policy. 
"9. The City shall require infill development to be designed to address compatibility with 
existing neighborhoods ." 
T he D CA in Section 18.790.050.D include regulatory incentives and flexible standards such as residential 
density transfer to retain significant tree groves (Vol. II , p. 153). In the density transfer option, 
compatibility with adjacent development with the same or lower density zoning would be ensured by 
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res tricting lot size reductions to 75 percent or greater of the base residential zoning district. T his would 
ensure compatibility with existing neighborhoods when designing infill development. 
In addition, the D CA in Section 18.790.030 would require the achievement o f tree canopy through 
planting, preservation or a fee in lieu to support the city's urban forestry program (Vol. II, p . 139) . The 
requil:em ents would apply to Minor Land Partitions, which are a primary contributor to infill development. 
As demonstrated by applying the code to infill development as part o f the peer review (Vol. II, 185) and 
further described in the Canopy Standards memo (Vol. V, p. 159), the amount o f tree canopy resulting 
from the recommended D evelopment Code is es timated to be compatible with existing neighborhoods. 
Therefore, the CPA and D CA are designed to require infill development to be compatible with existing 
neighborhoods, consistent with this policy. 
PUBLIC FACILITIES 
"GOAL: 
11.1 Develop and maintain a stormwater system that protects development, water resources, 
and wildlife habitat." 
"POLICIES: ... 
7. The City shall encourage low impact development practices and other measures that 
reduce the amount of, and/ or treat, stormwater runoff at the source." 
T he D CA in Section 18. 790.050.D (Vol. II, p. 153) include regulatory incentives and flexible standards to 
retai11 significant tree groves. In addition, the D CA i11 Section 18.790.030 would require the achievement 
o f tree canopy through planti11g, preservation or a fee in lieu to support the city's urban forestry program 
(Vol. II , p . 139) . 
In addition, the discretionary Urban Fores try Plan review option (Vol. II, p. 143) would allow the use o f 
techniques that minimize hydrological impacts, such as those detailed in Clean Water Services LIDA 
H andbook, as an alternative to meeti11g the clear and objective Urban Forestry Plan requirements. 
T he T ree Values Memo (Vol. V, p . 149) documents the ability o f trees to reduce and treat stormwater at 
the source. The Clean Water Services LIDA Handbook also documents the ability of the constructed 
system s detailed, withi11 the handbook, to reduce and treat stormwater at the source. T herefore, the CPA 
and D CA encourage low impact development practices and other measures that reduce the amount of 
and/ or treat stormwater at the source, consistent with this policy. 
TRANSPORTATION 
"GOAL: 
12.1: Develop mutually supportive land use and transportation plans to enhance the livability of 
the community." 
"POLICIES: ... 
6. The City shall support land use patterns that reduce greenhouse gas emissions and 
preserve the function of the transportation system." 
The D CA incorporate trees, and significant tree groves, within existing land uses and the transportation 
system (Vol. II, pp. 3-184). The Tree Values Mem o details the ability o f trees to reduce greenhouse gas 
emissions through sequestration and shading, which reduces fossil fuel consumption (Vol. V, p. 149) . 
T here fore, the CPA and D CA support land use patterns that reduce greenhouse gas emissions and 
preserve the function of the transportation system, consistent with this policy. 
ENERGY 
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"GOAL: 
13.1: Reduce energy consumption." 
"POLICIES: ... 
3. The City shall require future development to consider topography, vegetation, and solar 
access during the design phase to reduce demands for artificial heating, cooling, and 
lighting ." 
T he D CA in Section 18. 790.050.D (Vol. II, p . 1 53) include regulatory incentives and flexible standards that 
would allow future development to consider retaining significant tree groves during the design phase. In 
addition, the D CA in Section 18.790.030 would require the achievement of tree canopy through planting, 
preserva tion or a fee in lieu to support the city's urban fores try program (Vol. II , p . 139). T hese CPA and 
D CA have been designed to be flexible and adaptive to allow future development to consider topography, 
trees and solar access during the design phase. 
In addition, the discretionary Urban Foresuy Plan review option (Vol. II, p . 143) would allow techniques 
such as solar to reduce the use of fossil fuels for hea ting, cooling, and lighting as an alternative to meeting 
th e clear and objective Urban Forestry Plan requirements. 
T he Tree Values Memo documents the ability of trees reduce demands for hea ting and cooling through 
strategic placement and shading (Vol. V, p . 149). T herefore, the flexibility in placement o f trees afforded 
by the D CA, and the allowa nce o f alternative techniques that minimize use o f fossil fuels, is consistent 
with this policy, which requires future development to be designed in ways that reduce demands for 
artificial heating, cooling and lighting. 
"6. The City shall support energy conservation by: . . . 
D) providing flexibility in the land use process to take advantage of solar radiation." 
T he D CA in Section 18.790.030 require the achievement o f tree canopy through planting, preserva tion or 
a fee in lieu to support the city's urban fores try program (Vol. II , p . 139). T hese D CA have been designed 
to provide flexibility in tree preserva tion and planting to take advantage o f solar radiation. 
In addition, the discretionary Urban Forestry Plan review option (Vol. II , p. 143) would allow the use of 
onsite energy production such as solar power as an alternative to meeting the clear and objective Urban 
Fores uy Plan requirements in Section 18.790.030 (Vol. II , p. 139). 
T herefore, the D CA support energy conserva tion by providing flexibility in the land use process to take 
advantage of solar radiation, consistent with this policy. 
URBANIZATION 
"GOAL: 
14.3. Promote Tigard citizens' interests in urban g rowth boundary expansion 
and other reg ional and s tate growth management decision." 
" POLICIES: ... 
3. The city shall maintain the low-density residential character of its existing single family 
residential neighborhoods and accommodate more intense urban land uses in its regional 
and town centers and within major transportation corridors to be consistent with Statewide 
Planning Goals and the Metro Framework Plan." 
T he D CA in Section 18.790.050.D include regulatory incentives and flexible standards such as reduction 
of minimum density and residential density transfer to retain significant tree groves (Vol. II , p . 1 53). 
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Reduction o f minimum residential density would be allowed based on the area of significant tree grove 
preserved. In the density transfer option, compatibility with adjacent development with the same.or lower 
density zoning would be ensured by res tricting lo t size reductions to 75 percent or grea ter of the base 
residential zoning district. T his measure allows for the maintenance o f the low-density residential character 
o f existing single-family residential neighborhoods, consistent with this policy 
SPECIAL PLANNING AREAS: DOWNTOWN 
"GOAL: . . . 
15.3 Develop and Improve the Open Space System and Integrate Natural Features into 
downtown." 
"POLICIES: 
1. Natural resource functions and values shall be integrated into downtown urban design." 
T here are no significant tree groves in downtown Tigard, so this policy is not applicable. 
"GOAL: . . . 
15.4 Develop comprehensive street and circulation improvements for pedestrians, automobiles, 
bicycles, and transit." 
"POLICIES: ... 
5. Streetscape and public area design shall focus on creating a pedestrian friendly 
environment without the visual dominance by automobile-oriented uses." 
T he D CA to Chapter 18.7 45.040 would continue to require street trees in downtown Tigard. Street trees 
enhance the pedestrian environment as further explained by the Tree Values Memo (Vol. V, p. 149). 
T herefore, the D CA contribute to streetscape and public area design that create a pedestrian friendly 
environment, consistent with this policy. 
CONCLUSION: Based on the analysis above, staff finds that the CPA and D CA in Volume II are 
consistent with the applicable goals and policies contained in the City of Tigard Comprehensive Plan. 
APPLICABLE METRO URBAN GROWTH MANAGEMENT FUNCTIONAL PLAN TITLES 
Metro Functional Plan Title 1- "The Regional Framework Plan calls for a compact urban form 
and a "fair-share" approach to meeting regional housing needs. It is the purpose of Title 1 to 
accomplish these policies by requiring each city and county to maintain or increase its housing 
capacity except as provided in section 3.07.120." 
To meet Title 1, each jurisdiction was required to determine its housing capacity and adopt minimum 
density requirements. Tigard adopted an 80% of minimum density requirement for development in 1998, 
which means that a development must build 80% of the maximum units allowed by the zoning 
designation. As provided in Section 3.07.120, a city or county may reduce the mininmm-zoned capacity to 
pro tect natural resources. 
T he CPA would es tablish an overlay district for 70 significant tree groves covering 527 acres. As further 
described in the T ree Grove ESEE Analysis (Vol. II, p . 219), Goal 5 rule requirements would allow 
significant tree groves within the overlay to be eligible for the recommended incentives and flexible 
standards for prese1vation in Section 18.790.050.0. T he analyses and conclusions found in the Statewide 
Planning Goal Analysis section of the Tigard Goal 5 E SEE Analysis for Significant Tree G roves (page 3-4 
through 3-58) explains how the city adhered to the Goal 5 process and meets the applicable 
criteria. Those analyses and conclusions are hereby explicitly incorporated into the fmdings of this staff 
report. T he recommended incentives and flexible standards would allow for the full development of 
property under current zoning. Alternatively, the significant tree grove portion o f a site may be removed 
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from the minimum density calculation, reducing the density o f the site, as allowed in Section 3.07.120 o f 
Title 1. 
In addition, the D CA in Section 18.790.030 require the achievement o f tree canopy through planting, 
preserva tion or a fee in lieu to support the city's urban fores try program (Vol. II, p. 139). These D CA have 
been designed to be flexible and adaptive to continue to allow for a compact urban form and a fair-shared 
approach to meeting regional housing needs, consistent with Metro Title 1. 
Metro Functional Plan Title 3- "To protect the beneficial water uses and functions and values of 
resources within the Water Quality and Flood Management Areas by limiting or mitigating the 
impact on these areas from development activities and protecting life and property from dangers 
associated with flooding." 
In 2002, the City of Tigard adopted CPA and D CA amendments to comply with Title 3 o f Metro 's Urban 
G rowth Management Functional Plan. Title 3 pro tects the region's health and public safety by reducing 
flood and landslide hazards, controlling soil erosion and reducing pollution of the region's waterways. 
Title 3 implements Statewide Planning Goals 5, 6 and 7 by protecting streams, rivers, wetlands and 
floodplains by avoiding, limiting or mitigating development in1pacts on these areas. T he areas subj ect to 
these requirements have been mapped and adopted by the Metro Council, specifically, the FEMA 1 00-year 
floodplain and the area o f inundation for the February 1996 flood. Title 3 also protects rivers and streams 
with buffers that are typically 50 feet wide, requires erosion and sediment co ntrol, planting o f native 
vegetation on stream banks when new development occurs and prohibits the storage of new uses o f 
uncontained hazardous material in water quality areas. Title 3 results in significant protection and 
enhancement o f that portion o f the urban fores t in streams and floodways. 
T he D CA in Section 18. 790.050.D (Vol. II , p. 153) include regulatory incentives and flexible standards to 
encourage the preservation o f significant tree groves. In addition, the D CA in Section 18.790.030 would 
require the achievement of tree canopy through planting, preservation or a fee in lieu to support the city's 
urban fores try program (Vol. II , p. 139) . While these CPA and D CA are not required to meet Title 3, they 
would result in the planting, preserva tion and maintenance of trees, which support wa ter quality, flood 
management and fish and wildlife conserva tion, as evidenced by the Tree Values Memo (Vol. V , p . 149), 
consistent with Metro Title 3. 
Metro Functional Plan Title 12 -- "The purpose of Title 12 is to help implement the policy of the 
Regional Framework Plan to protect existing residential neighborhoods from air and water 
pollution, noise and crime and to provide adequate levels of public services." 
Title 12 protects residential neighborhoods by prohibiting cities from increasing density in certain areas, 
providing access to commercial services within neighborhoods while no t creating excessive traffic, noise or 
air pollution. It also requires sa fe and convenient walking/ biking access to schools, parks and greenspaces 
for city residents. 
During the Urban Foresu; ' Mas ter Plan process, the community identified the urban fores t as a key 
component of residential neighborhoods (Vol. V, p . 207). In addition, the Tree Values Memo describes 
the positive contribution o f trees to preventing air and water pollution, noise and crime (Vol. V, p . 149). 
The CPA and D CA would incorporate trees and significant tree groves into residential neighborhoods 
while allowing for the provision o f adequate levels o f public services, consistent with Metro Title 12. 
Metro Functional Plan Title 13 - "The purposes of this program are to (1) conserve, protect, and 
restore a continuous ecologically viable streamside corridor system, from the streams' headwaters 
to their confluence with other s treams and rivers, and with their floodplains in a manner that is 
integrated with upland wildlife habitat and with the surrounding urban landscape; and (2) to 
control and prevent water pollution for the protection of the public health and safety, and to 
maintain and improve water quality throughout the region." 
URR--\N FORESTRY CODE REYTSION PROJECT- Staff Report to the City Council 
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O ne of the results of Title 13 was the creation, in the City of Tigard, of 588 acres of habitat designa ted as 
" highest" value (i.e. Metro inventoried Class I and II riparian resources within the Clean Water Services 
Vegetated Corridor). An estimated 370 acres of Class I and II riparian habitat situated outside the Clean 
Water Services' vegetated corridor are designated as "moderate" value. In addition, 422 acres of non-Class 
I and II riparian resources within the city are designated as "lowest" value, including both upland forests 
and lower-value riparian habitat areas. The highest and moderate value habitats are currently protected 
through other regulatory processes and agencies such as Clean Water Services. The lowest value habitat 
consists of primarily upland forests and is currently vulnerable to development. Approximately 22% or 11 8 
acres of the significant tree groves are located on buildable lands outside of Title 3 sensitive lands and 
overlap with the lowest value habitat described above. 
The CPA would establish an overlay district for 70 significant tree groves covering 527 acres . As further 
described in the Tree Grove ESEE Analysis 0' ol. II, p. 219), G oal 5 rule requirements would allow 
significant tree groves within the overlay to be eligible for the recommended incentives and flexible 
standards for preservation in Section 18.790.050.D. The analyses and conclusions found in the Statewide 
Planning Goal Analysis section of the Tigard Goal 5 ESEE Analysis for Significant Tree Groves (page 3-4 
through 3-58) explains how the city adhered to the Goal 5 process and meets the applicable 
criteria. Those analyses and conclusions are hereby explicitly incorporated into the findings of this staff 
report. Regulatory incentives and flexible standards include allowed reduction in minimum density, density 
transfer, increased building height, reduced setbacks, adjustments to Urban Forestry Plan requirements 
and adjustments to street and utility standards. 
Although the city is in compliance with T itle 13, tl1e regulatory incentives and flexible standards that 
facilitate the preservation of significant tree groves are consistent with and supportive of Metro Title 13, 
particularly with regards to preserving vulnerable upland habitat designated through Title 13. 
CONCLUSION: Based on the analysis above, staff finds that the CPA and D CA in Volume II are 
consistent with the applicable Metro regulations. 
FEDERAL OR STATE STATUTES OR REGULATIONS 
Federal Endangered Species Act 
In 1973, the Federal Government passed the E ndangered Species Act to protect and recover imperiled 
species and the ecosystems on which they depend. Under Statewide Planning Goal 5, local governments 
are required to obtain current habita t inventory information for wildlife habitat inventories. Tigard 
previously adopted the significant habitat areas map, based on the inventory of regionally significant 
riparian corridors and wildlife habitat completed by Metro in 2002. 
The city identified 70 significant tree groves using wildlife habitat value and connectivity as a key criterion 
as further explained in the Tree Grove ESEE Analysis 0' ol. II , p. 232). The analyses and conclusions 
found in tl1e Statewide Planning Goal Analysis section of the Tigard Goal 5 ESEE Analysis for Significant 
Tree Groves (page 3-4 through 3-58) explains how the city adhered to the Goal 5 process and meets the 
applicable criteria. Those analyses and conclusions are hereby explicitly incorporated into the findings of 
this staff report.The significant tree grove map (Exhibit A) identifies the location of these 70 significant 
tree groves. 
T he D CA in Section 18. 790.050.D include regulatory incentives and flexible standards to preserve 
significant tree groves 0' ol. II , p. 153). In utilizing these regulatory incentives and flexible standards, 
applicants are required to maxinUze the connectivity of the remaining portion of the significant tree grove 
under the direction of a certified arborist or landscape architect. While endangered species were not 
specifically inventoried as part this process, the preservation of significant tree groves is supportive of their 
preservation to the extent that they depend on these habitats. Therefore, the CPA and D CA, for the 
preservation of significant tree groves, contribute to the protection of wildlife habitat in support of the 
E ndangered Species Act. 
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Federal Clean Water Act 
The Federal Clean Water 1\ ct regulates impacts to wetlands and other navigable waters o f the United 
States. T he State D epartment o f E nvil'Onmental Quality is also charged with es tablishing standards, 
regulating and monitoring Oregon's waters for compliance with the Federal Clean Water Act and N ational 
Pollutant Discharge E limination System . Within Tigard, runoff from impervious surfaces, pet was te and 
erosion / sedin1entation are the mos t problematic sources o f water pollution. 
T he D CA in Section 18.790.050.D include regulatory incentives and flexible standards to facilitate the 
preserva tion o f significant tree groves (Vol. II , p . 153). In addition, the D CA in Section 18.790.030 require 
the achievement o f tree canopy through planting, preserva tion or a fee in lieu to support the city's urban 
fores try program (Vol. II , p . 139). T hese D C1\ would result in the preserva tion and planting of trees, 
which have a positive contribution to water quality, as evidenced by the Tree Values Mem o (Vol. V, p . 
149). While the CPA and D CA in this application are not required for compliance, they are supportive o f 
Federal Clean Water Act requirements. 
Federal Migratory Bird Treaty Act 
T he Migratory Bird Treaty Act is a federal law adrninistered by US Fish and Wildlife that protects 
specifically listed species of birds. The CPA and D CA address the preserva tion, planting, and maintenance 
o f trees. When removing trees, it is the sole responsibility o f applicants to comply with all applicable state 
and federal regulations such as the Migratory Bird Trea ty Act. 
Implementing federal regulations to protect listed species o f birds is out o f scope for this application, and 
therefore the Federal Migratory Bu·d Treaty Act is not applicable. 
Oregon Department of Transportation (ODOT) O DOT manages approximately 283 acres o f right o f 
way in the City o f Tigard, including H all Boulevard, Highways 21 7 and 99-W and Interstate 5. State 
Bulletin RD06-03(B) provides specifications for street tree placem ent and maintenance in ODOT rights of 
way. These specifications are intended to balance the need for sa fety along state roadways with the 
planting and maintenance o f street trees . 
O D OT served on the Technical Advisory Committee for the Urban Forestry Code Revisions Project. O ne 
o f the purposes of O DOT's participation was to meet a project goal o f clarifying jurisdictional 
requirements. The city and ODOT met this goal by defining street and median trees as trees within right 
of way under City o f Tigard jurisdiction in Chapter 18.120 (Vol. II, p. 27) . This recommended 
development code amendment would clarify that trees within ODOT right o f way are under ODOT 
jurisdiction. Since the city and O DOT have differing standards for street tree planting, the D CA would 
ensure consistency with O D OT requirements by allowing each jurisdiction to apply its regulations 
separately in right o f ways under its jurisdiction. 
CONCLUSION: Based on the analysis above, staff fmd s that the CP 1\ and D C1\ in Volume II support 
(or do not conflict) with state or federal regulations. 1\ll affected agencies have been no tified o f the 
recommended amendments and have been given the opportunity to comment. 
STATEWIDE PLANNING GOALS 
Statewide Planning Goal 1, Citizen Involvement, outlines the citizen involvem ent requirements for 
adoption o f, and changes to the Comprehensive Plans and implementing documents. 
1\ s described in the Process Summary, the city has provided Tigard citizens, affected agencies and o ther 
jurisdictions multiple and varied opportunities to participate in all phases o f the urban forestry planning 
process (Vol. I, p . 26) . T his included 11 Citizen Advisory Committee meeti11gs where people representing 
diverse interes ts and viewp oints discussed and reviewed code concepts and code language at 11 meetings 
hosted by an independent facilitator. In addition, the Technical Advisory Committee, which included 
representatives from multiple city departments such as Public Works and Community D evelopment, and 
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outside agencies such as the O D OT and Clean Water Services, met 14 times to discuss and review code 
concepts and language resulting from the Citizen Advisory Committee process . 
The city identified 70 significant tree groves through the statewide Goal 5 planning process as further 
explained in the Tree Grove ESEE Analysis ('l ol. II , p. 219). The analyses and conclusions found in the 
Statewide Planning Goal Analysis section of the Tigard Goal 5 ESEE Analysis for Significant Tree Groves 
(page 3-4 through 3-58) explains how the city adhered to the Goal 5 process and meets the applicable 
criteria. Those analyses and conclusions are hereby explicitly incorporated into the fmdings of this staff 
report. The significant tree grove map (Exhibit A) identifies the location of these 70 significant tree groves. 
In additon, 14,225 public hearing notices consistent with Measure 56 were sent to all Tigard property 
owners on January 13, 2012. Public hearing no tices were also provided to interested parties on January 17, 
2012, to affected agencies on January 20, 2012, and published in the Tigard Times on January 19, 2012. 
The recommended amendments were further considered through the public hearing process at the 
Planning Commission and will be considered by City Council prior to adoption. Citizen involvement 
opportunities utilized to create the CPA and D CA have been consistent with Statewide Planning Goal1. 
Statewide Planning Goal 2, Land Use Planning, establishes a land use planning process and policy 
framework as a basis for all decisions and actions related to use of land and to assure an adequate factual 
base for such decisions and actions. 
The city identified 70 significant tree groves through the statewide Goal 5 planning process as further 
explained in the Tree Grove ESEE Analysis 01 ol. II, p. 21 9). The analyses and conclusions found in the 
Statewide Planning Goal Analysis section of the Tigard Goal 5 ESEE Analysis for Significant Tree Groves 
(page 3-4 through 3-58) explains how the city adhered to the Goal 5 process and meets the applicable 
criteria. Those analyses and conclusions are hereby explicitly incorporated into the fmdings of this staff 
report. T he significant tree grove map (Exhibit A) identifies the location of these 70 significant tree groves. 
The CPA and D CA are being processed as a Type IV procedure, which requires any applicable Statewide 
Planning Goals, federal or state statutes or regulations, METRO regulations, Comprehensive Plan policies 
and city's implementing ordinances, be addressed as part of tl1e decision-making process. All applicable 
review criteria have been addressed within this staff report. Therefore, the requirements of Statewide 
Planning Goal 2 have been met. 
Statewide Planning Goal 5, Natural Resources, requires the inventory and protection of natural 
resources, open spaces, historic areas and sites suitable for removal and processing of mineral and 
aggregate resources. 
The CPA would establish an overlay district for 70 significant tree groves covering 527 acres in compliance 
with Goal 5 rule requirements. As further explained in the Tree Grove ESEE Analysis, key evaluation 
criteria in the inventory and selection of significant tree groves were grove maturity/ tree size, grove size, 
health/ viability, visibility, screening and buffering, accessibility, rarity, educational/ recrea tional potential, 
wildlife habitat value and connectivity and the amount of existing disturbance 01 ol. II, p. 219). The 
analyses and conclusions found in the Statewide Planning Goal Analysis section of the Tigard Goal 5 
ESEE Analysis for Significant Tree Groves (page 3-4 through 3-58) explains how the city adhered to the 
Goal 5 process and meets the applicable criteria. Those analyses and conclusions are hereby explicitly 
incorporated into the fmdings of this staff report. 
During the inventory phase, all property owners with an inventoried tree grove on their property were 
provided notice, compliant with Goal 5 rule requirements. As part of the notice, property owners were 
invited to a tree grove open house, which was held on October 6, 2010, to learn more and provide 
feedback about the process. 
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T he D CA in Section 18.790.050.D (Vol. II , p. 153) include regulatory incentives and flexible standards that 
allow for the preservation of significant tree groves. 
Therefore, the CPA and D CA for significant tree groves would result in a limited protection program in 
compliance with Statewide Planning Goal 5. 
Goal 5 reguirements are no t applicable to recommended code amendments that support general urban 
forest enhancement activities, such as tree planting and preserva tion, when not associated with significant 
tree groves. These ac tivities do not create or amend a resource list or land use regulation adopted in order 
to protect a Goal 5 resource. 
Statewide Planning Goal 6, Air, Water and Land Resource Quality, reguires the maintenance and 
improvement o f the guality of the air, water and land resources of the state 
The city identified 70 significant tree groves through the statewide Goal 5 planning process as further 
explained in the T ree Grove ESEE Analysis (Vol. II, p. 219). The analyses and conclusions found in the 
Statewide Planning Goal Analysis section of the Tigard Goal 5 ESEE Analysis for Significant T ree G roves 
(page 3-4 through 3-58) explains how the city adhered to the Goal 5 process and meets the applicable 
criteria. Those analyses and conclusions are hereby explicitly incorporated into the findings of this staff 
report. The significant tree grove map (Exhibit A) identifies the location o f these 70 significant tree groves. 
T he DCA in Section 18.790.050.D include regulatory incentives and flexible standards to encourage the 
maintenance and improvement of significant tree groves (Vol. II , p . 153). 
In addition, the D CA in Section 18.790.030 reguire the achievement o f tree canopy through planting, 
presetvation or a fee in lieu to support the city's urban fores try program (Vol. II , p. 139). One benefit of 
these D CA is they encourage the maintenance and improvement of tree canopy citywide, which as further 
detailed in the Tree Values Memo (Vol. V, p. 149), is well documented to have a positive contribution to 
air guality. Therefore, the CPA and D CA are consistent with Statewide Planning Goal 6. 
Statewide Planning Goal 7, Areas Subject to Natural H azards, reguires the pro tection of life and 
property from natural disas ters and hazards. 
The city identified 70 significant tree groves through the statewide Goal 5 planning process as further 
explained in the Tree G rove ESEE Analysis (Vol. II, p. 219). The analyses and conclusions found in the 
Statewide Planning Goal Analysis section of the Tigard Goal 5 ESEE Analysis for Significant T ree G roves 
(page 3-4 through 3-58) explains how the city adhered to the Goal 5 process and meets the applicable 
criteria. Those analyses and conclusions are hereby explicitly incorporated into the findings of this staff 
report. T he significant tree grove map (Exhibit A) identifies the location of these 70 significant tree groves, 
many of which overlap areas subject to natural hazards. 
In addition, the D CA in Section 18.790.030 reguire the achievement of tree canopy through planting, 
preservation or a fee in lieu to support the city's urban forestry program (Vol. II , p. 139). In meeting tree 
canopy standards, trees may be planted or presetved in lands subject to natural hazards. 
One benefit of these CPA and D CA is that tree roots , canopies and leaf litter have the ability to prevent 
erosion and thereby protect areas subject to natural hazards. T his is more fully described in the Tree 
Values Memo (Vol. V, p. 149). T herefore, the CPA and D CA are consistent with, and supportive of 
Statewide Planning Goal 7. 
Statewide Planning Goal S, Recreational Opportunities , reguires sa tisfaction of the recreational needs 
of the citizens o f the state and visitors. 
T he city identified 70 significant tree groves using visibility, accessibility and educa tional/ recreational 
potential as key criteria as further explained in the Tree Grove ESEE Analysis (Vol. II , p . 232). The 
analyses and conclusions found in the Statewide Planning Goal Analysis section of the Tigard Goal 5 
URR-\N FORES1XY CODE RE\1SJON PROJECT- Staff Report to the City Cow1eil 
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ESEE Analysis for Significant Tree Groves (page 3-4 through 3-S8) explains how the city adhered to the 
Goal S process and meets the applicable criteria. Those analyses and conclusions are hereby explicitly 
incorpora ted into the findings of this staff report. T he significant tree grove map (Exhibit A) identifies the 
location of these 70 significant tree groves, many of which overlap with the city's parks and open space 
resources. 
The D CA in Section 18. 790.0SO.D (Vol. II, p . 1S3) include regulatory incentives and flexible standards to 
preserve significant tree groves. In utilizing these regulatory incentives and flexible standards, applicants 
are required to maximize the connectivity and viability of the remaining portion of the significant tree 
grove under the direction of a certified arborist or landscape architect. 
Significant tree groves provide opportunities for passive and active recreational opportunities for citizens 
of the state. Therefore, the CPA and D CA are consistent with Statewide Planning Goal S. 
Statewide Planning Goal 9, Economic Development, requires prov1s10n of adequate opporturutles 
throughout the state for a variety of economic activities vital to public health, welfare and prosperity. 
The city identified 70 significant tree groves through the statewide Goal S planning process as further 
explained in the Tree Grove ESEE Analysis (Vol. II , p. 219) . The analyses and conclusions found in the 
Statewide Planning Goal Analysis section of the Tigard Goal S ESEE Analysis for Significant Tree Groves 
(page 3-4 through 3-S8) explains how the city adhered to the Goal S process and meets the applicable 
criteria. Those analyses and conclusions are hereby explicitly incorporated into the findings of this staff 
report. The significant tree grove map (Exhibit A) identifies the location of these 70 significant tree groves . 
The D CA in Section 18.790.0SO.D include regulatory incentives and flexible standards to preserve 
significant tree groves (Vol. II , p . 1S3) . 
In addition, the D CA in Section 18.790.030 require the achievement of tree canopy through planting, 
preservation or a fee in lieu to support the city's urban forestry program (Vol. II , p. 139). 
These CPA and D CA have been designed to be flexible and adaptive to promote economic development 
opportunities and allow the provision of required infras tructure, consistent with Statewide Planning Goal 
9. 
Statewide Planning Goal 10, Housing, requires balancing the needs of tree and forest planting and 
preservation with the need for housing and efficient use of urban land. 
The city identified 70 significant tree groves through the statewide Goal S planning process as further 
explained in the Tree Grove ESEE Analysis (Vol. II , p. 219). The analyses and conclusions found in the 
Statewide Planning Goal Analysis section of the Tigard GoalS ESEE Analysis for Significant Tree Groves 
(page 3-4 through 3-S8) explains how the city adhered to the Goal S process and meets the applicable 
criteria. Those analyses and conclusions are hereby explicitly incorporated into the findings of this staff 
report. The D CA in Section 18.790.0SO.D include regulatory incentives and flexible standards that allow 
for the preservation of significant tree groves (Vol. II, p. 1S3). Regulatory incentives and flexible standards 
also provide for needed housing and promote the efficient use of land by allowing density transfer, 
increased building height, reduced setbacks, adjustments to Urban Forestry Plan requirements and 
adjustments to street and utility standards. 
In addition, the D CA in Section 18.790.030 provide flexibility for meeting tree canopy requirements 
through planting, preserva tion or a fee in lieu to support the city's urban forestry program (Vol. II , P . 139). 
T lus would allow applicants to design sites efficiently while providing needed housing and incorporating 
trees. 
T herefore, the CPA and D CA are consistent with and supportive of Statewide Planning Goal 10 willie 
meeting the city's urban forestry goals. 
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Statewide Planning Goal 11, Public Facilities/Services, requires planning and development of a 
timely, orderly and efficient arrangement of public facilities and services to se1ve as a framework for urban 
and rural development. 
T he city identified 70 significant tree groves through the statewide Goal 5 planning process as further 
explained in the Tree Grove ESEE Analysis 01 ol. II, p. 219). The analyses and conclusions found in the 
Statewide Planning Goal Analysis section o f the Tigard Goal 5 ESEE Analysis for Significant Tree Groves 
(page 3-4 through 3-58) explains how the city adhered to the Goal 5 process and meets the applicable 
criteria. Those analyses and conclusions are hereby explicitly incorporated into the fmdings of this staff 
report. T he DCA in Section 18.790.050.D include regulatory incentives and flexible standards that allow 
for the preservation of significant tree groves 01 ol. II, p . 153). Regulatory incentives and flexible standards 
would allow adjustments to street and utility standards. 
In addition, the D CA in Section 18.790.030 provide flexibility for meeting tree canopy requirements 
through planting, preserva tion or a fee in lieu to support the city's urban fores try program 01 ol. II, p . 139). 
T herefore, the CPA and DCA are consistent with and supportive of Statewide Planning Goal 11 because 
they allow maxin1um flexibility for the efficient arrangement of public facilities while incorporating trees. 
Statewide Planning Goal 12, Transportation, requires provision of a sa fe, convenient and economic 
transportation system. 
The city identified 70 significant tree groves through the statewide Goal 5 planning process as further 
explained in the T ree Grove ESEE Analysis 01 ol. II, p . 219). T he analyses and conclusions found in the 
Statewide Planning Goal Analysis section of the Tigard Goal 5 ESEE Analysis for Significant Tree Groves 
(page 3-4 through 3-58) explains how the city adhered to the Goal 5 process and meets the applicable 
criteria. Those analyses and conclusions are hereby explicitly incorporated into the findings of this staff 
report. As sta ted above, the D CA in Section 18.790.050.D include regulatory incentives and flexible 
standards that allow for the preservation of significant tree groves 01 ol. II, p . 153). Regulatory incentives 
and flexible standards would allow adjustments to street and utili ty standards. 
In addition, the D CA in Section 18.790.030 provide flexibility for meeting tree canopy requirements 
through planting, preservation or a fee in lieu to support the city's urban fores try program 01 ol. II, p. 139). 
T herefore, the CPA and D CA are consistent with, and supportive of Statewide Planning Goal 12 because 
they allow maximum flexibility for a safe, convenient and econol11ic transportation system while 
incorporating trees. 
Statewide Planning Goal13, Energy Conservation, requires land and uses developed on the land to be 
managed and controlled to maxinuze the conservation o f all forms o f energy, based upon sound econol11ic 
principles. 
T he city identified 70 sigtuficant tree groves through the statewide Goal 5 plamung process as further 
explained in the T ree G rove ESEE Analysis 01 ol. II, p. 219). The analyses and conclusions found in the 
Statewide Plam1ing Goal Analysis section o f the Tigard Goal 5 ESEE Analysis for Sigtuficant Tree Groves 
(page 3-4 through 3-58) explains how the city adhered to the Goal 5 process and meets the applicable 
criteria . Those analyses and conclusions are hereby explicitly incorporated into the findings of this staff 
report. The D CA in Section 18. 790.050.D include regulatory incentives and flexible standards that allow 
for the preservation of significant tree groves 01 ol. II, p . 153). In addition, the D CA in Section 18.790.030 
require the achievement of tree canopy through planting, preserva tion or a fee in lieu to support the city's 
urban forestry program 01 ol. II, p. 139). 
In addition, the discretionary Urban Fores try Plan review option 01ol. II, p . 143) allows the use techniques 
such as solar power generation that 111ininUze the use of fossil fuels an alternative to meeting the clear and 
objective Urban Forestry Plan requirements in Section 18.790.030. 
URR-\N FORESTRY CODE RE\'1SION PROJECT- Staff Report to the City CowKil 
CP.-\ 2011 -00004/ DC -\ 2011 -00002 
City o f Tigard Urban l'orcstry Code Rc,·isiom I \' olumc II I 45R 
P.-\GE 38 OF 40 
The Tree Values Memo documents the ability of trees to reduce energy demands through strategic 
placement and shading (Vol. V, p. 149). Therefore, the flexibility in placement of trees afforded by the 
DCA, and the allowance of alternative techniques that minimize use of fossil fuels, are consistent with 
Statewide Planning Goal 13, which seeks to maximize energy conservation based on sound economic 
principles. 
Statewide Planning Goal 14, Urbanization, requires provlSlon for an orderly and efficient transition 
from mral to urban land use, to accommodate urban population and urban employment inside urban 
growth boundaries, to ensure efficient use of land and to provide for livable communities. 
The city identified 70 significant tree groves through the statewide Goal 5 planning process as further 
explained in the Tree Grove ESEE Analysis (Vol. II , p. 219). The analyses and conclusions found in the 
Statewide Planning Goal Analysis section of the Tigard Goal 5 ESEE Analysis for Significant Tree Groves 
(page 3-4 through 3-58) explains how the city adhered to the Goal 5 process and meets the applicable 
criteria. Those analyses and conclusions are hereby explicitly incorporated into the findings of this staff 
report. The D CA in Section 18. 790.050.D include regulatory incentives and flexible standards that allow 
for the preservation of significant tree groves (Vol. II, p. 153). Regulatory incentives and flexible standards 
would allow density transfer, increased building height, reduced setbacks, adjustments to Urban Forestry 
Plan requirements and adjustments to street and utility standards. 
In addition, the DCA in Section 18.790.030 provide flexibility for meeting tree canopy requirements 
through planting, preservation or a fee in lieu to support the city's urban forestry program (Vol. II, p. 139). 
Therefore, the CPA and DCA provide flexibility in tree preservation and planting strategies to allow for 
the efficient use of land to accommodate urban population and employment within the urban growth 
boundary, consistent with Statewide Planning Goal14. 
Inapplicable Statewide Planning Goals include Goal 3 (Agricultural Lands) and Goal 4 (Forest Lands) 
because they address rural land outside the Metro Urban Growth Boundary; Goal 15 (Willamette River 
Greenway), because the Willamette River does not flow through Tigard; and Goals 16 (Estuarine 
Resources), 17 (Coastal Shorelines), 18 (Beaches and Dunes), and 19 (Ocean Resources), because they 
relate to Oregon's coastal resources. 
CONCLUSION_;_ Based on the analysis above, staff finds that the recommended amendments are 
consistent with the applicable Statewide Planning Goals. 
SECTION V. CITIZEN COMMENTS 
Comments were received in response to the Measure 56 notice to all city property owners and public 
hearing notices to interested parties. These comments were provided to the Planning Commission when 
received during their portion of the legislative adoption process and will be provided to City Council when 
received during their portion of the legislative adoption process. All citizen comments are available in the 
project record. 
SECTION VI. AGENCY COMMENTS 
Metro- Land use and Planning, Washington County Department of Land Use & Transportation, 
U.S. Army Corps of Engineers, Oregon Department of State Lands, Oregon Department of Land 
Conservation and Development, and Oregon Department of Environmental Quality, Tualatin 
Valley Fire & Rescue, Tigard-Tualatin School District 23J were given the opportunity to review this 
proposal and submitted no comments or objections. 
The cities of Tualatin, Lake Oswego, Beaverton, King City and Durham were given the opportunity 
to review this proposal and submitted no comments or objections. 
URBAN FORESTRY CODE REVISION PROJECT- Staff Report to the City Council 
CPA 2011 -00004/ DCA 2011 -00002 
City of Tigard Urban Forestry Code Re1·isions I Volume II I 459 
PAGE39 OF40 
Oregon Department of Transportation and Clean Water Services have reviewed the proposal as 
members of the Technical Advisory Committee and provided input that contributed to the recommended 
amendments. 
Oregon Department of Fish and Wildlife provided comments, which were provided to the Planning 
Commission and are available in the project record. 
Verizon, Comcast Cable Corp, Qwest Communications, Portland General Electric and NW 
Natural Gas Company were given the opportunity to review this proposal and submitted no comments 
or objections. 
PRE PARE D BY: 
REVIEWED BY: 
Gary Pagenstecher 
Associate Planner 
Ron Bunch 
Community D evelopment Director 
URK\N FORESTRY CODE RE\riSION PROJECT- Staff Report to the City Council 
CP[\ 2011 -00004/ DCA 2011 -00002 
City of Tigard Urban l'orc> try Code Rc,-i,iom I \'olumc II I 4(,0 
DATE 
DATE 
P"-\GE 40 OF 40 
Significant Tree Groves 
City of Tigard 
70 groves 
527 acres 
0.25 0.5 
Sign ificant Habitat 
Tigard City Boundary 
6. 
N 
City of Tigard 
COMMUNITY DEVELOPJ\ffiNT DEPARTJ\ffiNT 
13125 SW Hall Blvd., Tigard, OR 97223 
www. tigard -or. gov / trees I 
Volume III: Table of Contents 
Organization of the Urban Forestry Code Revisions Documents 1 
Tigard Municipal Code - Staff Recommendation 
How to Read This Section 
Table of Code Sections .......... .............. ................. ................... .. ....... .. ......... ............... .. ........ .. .. ....... ............. 3 
Code Amendments 
Chapter 1.16 Civil Infractions ........................................................................... ... ..... ................. ................... . 5 
Chapter 6.01 General Provisions and Penalties .................. ...................... .. .................... .... .................... 11 
Chapter 6.02 Nuisances Affecting Public Health, Safety and Peace .................... ....... ...... ... ............ 15 
Chapter 8.02 Definitions and Administrative Rules ........... ...................... ... ...... .. .......... .... .................... 23 
Chapter 8.04 Tree Permit Procedures ....................................................................................... ... ... .......... 43 
Chapter 8.06 Hazard Trees ........................................................... .............. .................................................. 49 
Chapter 8.08 Street and Median Trees ......... ........ ........................... .. ............... .... ..................................... 53 
Chapter 8.10 Trees in Sensitive Lands ....... : ................... .. .......................... ... .................................. .......... 59 
Chapter 8.12 Trees That Were Required With Development .. .. ......................................... .. ........ .... 63 
Chapter 8.14 Trees That Were Planted Using the Urban Forestry Fund ... ............... ..... ..... .. .... .. ... 67 
Chapter 8.16 Heritage Trees ................. ................... .............. .................. .. ................................................... 71 
Chapter 9.06 Trees on City Property .... ........ ...... .. ................................................ ... ............ ... ......... .... ...... 83 
Chapter 9.08 Heritage Trees ................................................ ............................................... .. .......... .... ... ....... 93 
Organization of the Urban Forestry Code Revisions D ocuments 
The Urban Forestry Code Revisions project is presented in five volumes. Volume I provides the 
project overview and describes the process used to develop all of the elements. Volume II is the 
land use elements of the code, and Volume III the non land use elements. Volume IV contains the 
Urban Forestry Manual. Volume V contains technical reports and research that contributed to the 
code revisions along with details of the public input and deliberations to date. 
Volume I I Project Overview 
Project Overview includes the following sections: 
• Project Introduction 
• Overview of K ey E lements 
• Key Element Summaries 
o Urban Forestry Standards for D evelopment 
o Tree Grove Preservation Incentives 
o Tree Permit Requirements 
o H azard Trees 
o Urban Forestry Manual 
Appendix A includes additional detail about the information used to shape the Urban 
Forestry Code Revisions Project, and includes the following sections: 
• Process summary 
• Summary of Community Ideas and Concerns 
• Summary of Planning Commission Deliberations 
• Existing Conditions 
Volume II I L and Use Elem ents 
Community D evelopment Code (Title 18) is the Planning Commission's recommended 
draft of the D evelopment Code. This section includes commentary on the amendments. 
Peer Review demonstrates how the Planning Commission's recommended draft of the 
Development Code and Urban Forestry Manual will work in application. 
Tree Grove E SEE Analysis is a report that addresses Statewide Planning Goal 5- Natural 
Resources requirements for the preservation of Significant Tree Groves. 
Staff Rep ort and findings includes the staff recommendation for approval of the land use 
elements (Title 18 and the Comprehensive Plan Amendment) and the findings that 
demonstrate the land use elements meet the necessary approval criteria. 
City of Tigard Urban l'orcstry Code Rc,·isiom I Volume Ill 11 
Volume III I Non Land Use Elements 
Tigard Municipal Code is the staff proposed draft of the Municipal Code (Title 8 and 
other Municipal Code titles). This section includes commentary on the amendments. 
Volume IV I Urban Forestry Manual (Administrative Rules) 
Urban Forestry Manual consists o f administrative rules that implement the technical 
details of the urban forestry related code provisions in Title 8, Title 18 and other applicable 
titles in the Tigard Municipal Code. 
Volume V I Additional Background Materials 
Planning Commission D eliberations details Planning Commission discussion and 
decisions during the public hearing process. 
Amendment Requests D ocument for the Planning Commission lists code amendment 
requests received in response to the ftrst Planning Commission public hearing and staff 
responses. 
Outstanding Issues for the U rban Forestry Code Revisions includes additional 
inform ation on the outstanding issues that were further deliberated by the Planning 
Commission before making their ftnal recommendation to City Council on May 7, 2012. 
Log of Input lists the input received and any code changes from the last meeting of the 
CAC to the staff proposed draft of the Urban Forestry Code Revisions to Planning 
Commission. 
CAC Guiding Principles includes the consensus view o f the Citizens Advisory Committee 
(CAC) developed to help guide the legislative adoption process . 
Tree Values includes information and curren t research on the environmental, economic, 
social and aesthetic beneftts of trees. 
Canopy Standards explains the reasons for adopting tree canopy cover requirements as 
well as the methods used to arrive at the requirements. 
Soil volume details research about the soil volume required to support a mature tree 
canopy. 
Tree Canopy Fee discusses research used to develop a square foo t value for tree canopy. 
Regulatory Comparison is an excerpted report prepared by Metro and the Audubon 
Society that summarizes and compares regional urban forestry programs and regulations. 
Urban Forestry M aster Plan is the City of Tigard's recommended plan for achieving the 
urban forestry goals in the Comprehensive Plan. 
Cirr ofTig;J rd Urbon l:orc> try Code Rcri>iom I \'olumc Ill I 2 
Tigard Municipal Code - Staff Recommendation 
How to Read This Section 
This section is organized by Municipal Code chapter number. Odd-numbered pages show the 
existing language with staff recommended amendments. Text that is recommended to be added to 
the code is shown with double underlines. Text that is recommended to be deleted is shown with 
strikethrough. 
Even-numbered pages contain commentary on the amendments, which establish, in part, the 
legislative intent in adopting these amendments. Staff recommends focusing on the commentary to 
gain a better understanding of the purpose of the code amendments. 
The Urban Forestry Manual consists of administrative rules that implement the details of the urban 
forestry related code provisions in Title 8, Title 18 and other applicable titles in the Tigard Municipal 
Code. Section 8.02.040 of the Tigard Municipal Code enables administrative rulemaking for the 
Urban Forestry Manual. The city manager is authorized to adopt and amend the Urban Forestry 
Manual according to the procedures in Chapter 2.04 after council adoption of Section 8.02.040. The 
Urban Forestry Manual is referenced as if it has already been adopted in order to demonstrate how it 
relates to the code. 
Table of Code Sections 
Chapter 1.16 Civil Infractions 
Chapter 6.01 General Provisions and Penalties .. .... .................................................. ....... .. ........... 9 
Chapter 6.02 Nuisances Affecting Public Health, Safety and Peace .................................... 13 
Chapter 8.02 Definitions and Administrative Rules ............... .. ............................................ .. .. 21 
Chapter 8.04 Tree Permit Procedures ...................................................................... ... ............ .... .. 41 
Chapter 8.06 Hazard Trees ... ... ........... ..................................................... .. ...................................... 47 
Chapter 8.08 Street and Median Trees ......................... .. ... ... .... ..................................................... 51 
Chapter 8.10 Trees in Sensitive Lands ......................................................... ...................... ........... 57 
Chapter 8.12 Trees That Were Required With Development ................................ ............... 61 
Chapter 8.14 Trees That Were Planted Using the Urban Forestry Fund ........................... 65 
Chapter 8.16 Heritage Trees ....... ... .................................................................................................. 69 
Chapter 9.06 Trees on City Property ............................... ........................................................... .. 81 
Chapter 9.08 Heritage Trees ...................................... .................. .. .. ... ... .... .. ..................... ............... 91 
Ci ty of Tigard Urban Forestry Code Rc,·isions I Volume Ill I 3 
Commentary 
1.16 Civil Infractions 
Currently, the " illegal tree removal" section in Chapter 18.790 outlines penalties for tree violations. 
As part of the city's Regulatory Improvement Initiative, similar code items are being consolidated 
wherever possible. Rather than retaining penalties for tree violations in Chapter 18.790, they are 
being moved to Chapter 1.16, where nuisance infractions are already consolidated. Penalties for 
violations of Title 8 (Urban Forestry) are also outlined in Chapter 1.1 6. 
The table of contents for Articles I, II , III , and IV of Chapter 1.16 are unchanged. See Section 
1.16.640 for code amendments. 
2 
City of T ig:1rd Urb:1n l;orc:-:try Code RcYi ~ion :-: I Volun1c I I I I 4 
Code Amendments 
Chapter 1.16 CIVIL INFRACTIONS. 
Sections: 
ARTICLE I. GENERAL PROVISIONS 
[No change to table of contents.] 
ARTICLE II. JUDICIAL ENFORCEMENT 
[No change to table of contents.] 
ARTICLE III. ADMINISTRATIVE ENFORCEMENT 
[No change to table of contents.] 
ARTICLE IV. PENALTIES, FEES AND COSTS 
[No change to table of contents.] 
3 
City of Tigard Urban Forestry Code Re,'isions I Volume Ill I 5 
Commentary 
1.1 6 Article I. G eneral Provisions 
Articles I, II and Ill are unchanged. Article IV, Sections 1.16.600 through 1.1 6.630 are unchanged. 
4 
Ciry nf Tigard Urban h)rc~try Code RcYi:-:ion ~ I \ 'olun1c II I I (J 
ARTICLE I. GENERAL PROVISIONS 
[No change.] 
ARTICLE II. JUDICIAL ENFORCEMENT 
[No change.] 
ARTICLE III. ADMINISTRATIVE ENFORCEMENT 
[No change.] 
ARTICLE IV. PENAL TIES, FEES AND COSTS 
1.16.600 through 1.16.630 
[No change.] 
City of Tigard Urban Forestry Code Re,·isions I Volume Ill I 7 
Code Amendments 
5 
Commentary 
1.16.640 Penalties and Fees-Amounts to be Assessed 
Violations o f Title 8 (Urban Forestry) and Title 18 (Community Development Code) are Class 1 civil 
infractions. Penalties for Class 1 civil infractions are contained in Section 1.16.640.A. 
Existing Chapter 18.790 outlines additional penalties for illegal tree removal, which includes a civil 
penalty o f up to $500, an additional penalty for the appraised value o f the tree and mitigation based 
on the size of tree removed. These additional penalties recognize the significant value that trees 
provide to the community and the fact that once a mature tree is removed, it cannot be replaced. 
Based on community discussions, additional penalties for illegal tree removal are still warranted. 
H owever, flexibility in the penalty amount is desired so that the city has the ability to scale the 
penalty based on the circumstances surrounding a particular case. A maximum penalty is desired to 
protect citizens from disproportionate amounts. 
During the development process, unauthorized moving, removing or damaging of tree protection 
fencing and failure to provide required arborist inspection reports have been chronic issues. In 
many cases, it is less expensive for violators to not comply, rather than hire an arborist as required. 
A minimum penalty that is more than the cost o f hiring an arborist will incentivize compliance and 
reduce city staff time and resources associated with enforcement. 
In addition to tl1e general Class 1 civil infraction penalties for noncompliance with Titles 8 and 18, 
the following specific penalties for the specific violations described above are: 
(, 
• A minimum fine of $250 for illegal tree rem oval and a maximum fine of the cost to 
plant and maintain for three years per tree care industry standards and the standards 
in the Urban Forestry Manual a number o f 1 Vz caliper trees equal to the diameter o f 
the tree removed; 
• A minimum fine of $250 and maximum fine o f $500 for unauthorized moving, 
removing or damaging of tree protection fencing; and 
• A minimum fine of $250 and maximum fine o f $500 for each late or omitted tree 
protection inspection reports. 
CitY nf Tigord Urbon l'orc>try Code Rni>iom I \'olumc Ill I H 
Code Amendments 
1.16.640 Penalties and Fees-Amounts to be Assessed 
The civil penalty or administrative fee to be assessed for a specific infraction shall be as 
follows: 
A. For Class 1 infractions, 
1. An amount not to exceed $250 per day under either the judicial or the 
administrative enforcement process; or 
2. Under the administrative enforcement process, an amount: 
a. Computed in a manner established by administrative rule pursuant to 
1.16.1 05. 
b. For the entire period the violation exists and not for each day of the 
violation~~ 
3. For the specific urban forestry violations listed in Section 8.02.030.F an 
amount remitted into the Urban Forestry Fund for tree planting and early establishment: 
a. Not less than $250 per unlawfully removed tree and not more than 
the city's cost to 1 d · · : h p ant a~ mamtam for three years an equivalent number of 1 li z inch r 
trees wtt a combtned caliper equal to the DBH of each unlawfully removed tree; ca tper 
b. Not less than $250 and not more than $500 for damaging moving or 
removing a tree protection fence; 
c. Not less than $250 and not more than $500 for each failure to 
provide inspection reports by the project arborist or landscape architect. 
B. For Class 2 infractions, an amount not to exceed $150 per day; 
C. For Class 3 infractions, an amount not to exceed $50 per day. (Ord. 86-20 
§1(Exhibit A (8)(D)), 1986). 
1.16.650 through 1.16.710 
[No change.] 
7 
City of Tigard Urb~n Fores try Code Rc,·isions I Volume Ill I 9 
Commentary 
6.01 G eneral Provisions and Penalties 
The purpose of Title 6 is to consolidate all nuisance violations into one place for ease of use. This is 
also consistent \vith the Regulatory Improvement Initiative. A nuisance is broadly defined as any 
non-criminal violation of the code that affects public health, safety and peace. 
Sections 6.01.020 (Definition of Noxious Vegetation), 6.02.030 (Trees and Bushes) and 6.02.040 
(Greenway Maintenance) contain provisions that address hazard trees. These provisions are slightly 
revised for consistency with hazard tree provisions in Title 8. 
~ 
City of'J'ig:ud Urb:1n h)rc~try Code Rc\'1;-;ion:-; I \ 'olun1e Ill I 10 
6.01.010 
6.01.020 
6.01.030 
6.01.040 
6.01.050 
6.01.060 
Chapter 6.01 
GENERAL PROVISIONS AND PENAL TIES 
Short Title 
Definitions 
Nuisances Designated-Class I Civil Infraction 
Penalty for Violation of This Title 
Administrative Rules 
Enforcement-Minimum Requirements 
6.01.010 Short Title 
[No change] 
6.01.020 Definitions 
As used in this title: 
A. through K. 
[No change.] 
Ciry of Tigard Urban l'orcstry Code Revisions I Volume Ill 111 
Code Amendments 
9 
Commentary 
6.01.020 Definitions 
This amendment is designed to replace a list of items with an inclusiYe term (yegetation) to aYoid 
identification of trees and stumps that might o therwise be beneficial for wildlife habitat and / or 
erosion control, and are no t "likely to cause fire". 
I( I 
Cit1· of'J'igord Urbon l'orcstr\' Code RcYisinm I \ 'olumc Ill I 12 
Code Amendments 
L. "Noxious vegetation" means: 
1. Weeds more than 10 inches high; 
2. Grass more than 10 inches high and not within the exception stated 111 
paragraph 9 of this subsection; 
3. Poison oak, poison ivy or similar vegetation; 
4. Dead trees. dead bushes. stumes and anv other thin~ Vegetation that is likely 
to cause ftre; 
5. Blackberry bushes that extend into a right-of-way or across a property line; 
6. Vegetation that is a health hazard; 
7. Vegetation that is a health hazard because it impairs the view of the right-of-
way or o therwise makes use of the right-of-way hazardous. 
8. Any of the following invasive and noxious plants: H edera helix L. (English 
ivy), H eracleum mantegazzianum (giant hogweed), Lythrum salicaria L. (purple loosestrife), 
Polygonum cuspidatum Qapanese knotweed), Rubus discolor (Himalayan blackberry); 
9. "Noxious vegetation" does not include vegetation that constitutes an 
agricultural crop, unless that vegetation is a health hazard, a ftre hazard or a trafftc hazard, and it is 
vegetation within the meaning of this subsection. 
M. through Z. 
[No change.] 
6.01.030 through 6.01.060 
[No change.] 
City of Tigord Urban l'orcstry Code Revisions J Volume Ill J1 3 
11 
Commentary 
6.02 N uisances A ffecting Public Health, Safety and Peace 
The purpose of Title 6 is to consolidate all nuisance violations into one place for ease of use. This is 
also consistent with the Regulatory Improvement Initiative. A nuisance is broadly defined as any 
non-criminal violation of the code. 
Sections 6.02.030 (Trees and Bushes) and 6.02.040 (Greenway Maintenance) contain provisions that 
address hazard trees. These provisions are slightly revised for consistency with hazard tree 
provisions in Title 8. 
The table of contents for Articles I, II, III , IV, V and VI of Chapter 6.02 are unchanged. See 
Sections 6.02.030 and 6.02.040 for code amendments. 
12 
CitY of 'J'igJrcl UrbJn l'orc"n· Code Rcvi>ion > I \ 'olumc Ill I 1-l 
Code Amendments 
Chapter 6.02 
NUISANCES AFFECTING PUBLIC HEALTH, SAFETY AND PEACE 
Sections: 
Article I. General Nuisances 
[No change to table of contents.] 
Article II. Property Development and Maintenance Requirements 
[No change to table of contents .] 
Article III. Junk, Garbage and Putrescible Waste 
[No change to table of contents.] 
Article IV. Streets and Sidewalks 
[No change to table of contents.] 
Article V. Noise Nuisances 
[No change to table of contents.] 
Article VI. Water Service and Meters 
[No change to table of con tents.] 
13 
City of Tigord Urban Fores try Code Revisions I Volume Ill I 15 
Commen tary 
6.02.030 Trees and Bushes 
According to the City of Tigard Streets Division, the minimum height for branch clearance over 
streets should be 13 feet. 
Hazard trees are clearly defined using industry standard terminology in Chapter 8.02, so a cross 
reference is included in Chapter 6.02 to ensure consistency in the use o f terms and to continue to 
treat hazard trees as nuisances. 
14 
CitY of T igord Urbon l'orc>trr Code Rcvi>inm I \' nlumc Ill I 16 
Code Amendments 
Article I. General Nuisances 
6.02.010 through 6.02.020 
[No change.] 
6.02.030 Trees and Bushes 
A. No responsible party shall permit branches or roots of trees or bushes on the 
property to extend into a right of way in a manner which interferes with its use. 
B. It shall be the duty of a responsible party to keep the branches of all trees or bushes 
on the premises that adjoin the right of way, including an adj oining parking strip, trimmed to a 
height of not less than eight feet above a sidewalk and not less than +G llfeet above a street. 
C. No responsible party shall allow to stand any hazard tree as defined in Chapter 
.8.ll2dead or deeaying tree that is in danger of fal:li:ag or othenvise eomtitutes a hazard to the publie 
or to persons or property on or near the property. 
15 
City ofTigord Urban Foremy Code Revisions I Volume Ill I 17 
Commentary 
6.02.040 Greenw·ay Maintenance 
The provisions o f Chapter 8. 10 (Trees in Sensitive Lands) address the removal o f trees in sensitive 
lands in a more comprehensive way than the existing provisions in Chapter 6.02.040. T he term 
"greenway" is no t defined in the code, and "sensitive lands" could be considered equivalent or 
somewhat more expansive. Removing the provisions of 6.02.040.B.2 is an interim solution until a 
more comprehensive review of Section 6.02.040 occurs. 
16 
CitY nfTig, rcl Urb' n l'nrc>trr Cock Rcri>inm I \"nlumc Ill I 1 ~ 
Code Am endments 
6.02.040 Greenway Maintenance 
A. A responsible party shall maintain the property, subject to an easement to the city or 
to the public for greenway purposes . 
B. Except as o therwise provided by this section and Sections 6.02.020 through 6.02.050, 
6.02.210 through 6.02.230, and 6.02.310, the standards for maintenance shall be as follows: 
1. Land shall remain in its natural topographic condition . No private structures, 
culverts, excavations or fills shall be constructed within the easement area unless authorized by the 
city engineer based on a finding of need in order to pro tect the property or the public health, safety 
or welfare. 
2. No tree ovel' five feet in height shall be l'emoved unless authOl'ized by the 
comnmnity development directol' based on a ft:nding that the tl'ee constitutes a nuisance ol' a hazal'd. 
; 2. G rass shall be kept cut to a height not exceeding 10 inches, except when 
some natural condition prevents cutting. 
C. In situations where the approval authority es tablishes different standards or 
additional standards, the standards shall be in writing and shall be recorded. 
D . No person shall be found in violation o f this section of the code unless the person 
has been given actual or constructive no tice of the standards prior to the time the violation 
occurred. 
6.02.050 through 6.02.070 
[No change.] 
17 
City ofTigard Urban Fores try Code Revisions I Volume 111 119 
Commentary 
6.02 Nuisances Affecting Public Health, Safety and Peace 
Unchanged sections of Chapter 6.02 continued. 
18 
CitY ofTigorcl Urbon l'orc>trv Code Rcvisiom I \ 'olumc Ill I 211 
Code Amendments 
Article II. Property Development and Maintenance Requirements 
[No change.] 
Article III. Junk, Garbage and Putrescible Waste 
[No change.] 
Article IV. Streets and Sidewalks 
[No change.] 
Article V. Noise Nuisances 
[No change.] 
Article VI. Water Service and Meters 
[No change.] 
City of Tigard Urban Foremy Code Revisions I Volume Ill I 21 
19 
Commentary 
Chapter 8.02 D EFIN IT IONS, PENALT IES AND ADMIN ISTRATIVE RULES 
Chapter 8.02 is a foundational chapter for Title 8. It creates the authority for adopting and amending 
administrative rules in the Urban Forestry Manual. It es tablishes penalties for urban forestry 
violations. It also establishes the definitions sections for Title 8 and the Urban Forestry Manual. 
8.02.010 Purpose 
The purpose statement explains that the chapter creates the authority to adopt and amend 
administrative rules in the Urban Forestry Manual. The purpose statement also explains the intent is 
to provide definition and consistency of terms between the various urban forestry related chapters in 
Title 8 and the Urban Forestry Manual. Finally, the purpose statement explains the chapter 
es tablishes penalties for urban forestry violations. 
211 
Cit y ofTig:1rcl Urb:-~ n l;orc:-; try Code R cvi ~ion ~ l \'nlUtnc: Ill I 22 
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Commentary 
8.02.020 G eneral Provisions 
Many trees are subj ect to the provisions of multiple chapters in Title 8. For example, a heritage tree 
may also be reguired to be preserved with development. When permitting the removal o f this type 
o f tree, the more restrictive provisions o f Chapter 8.16 (H eritage Trees) would apply. 
Trees that are permitted to be planted, removed or replaced by a Title 18 land use permit do not also 
reguire a Title 8 tree permit. For example, street trees reguired to be planted by Chapter 18.745 do 
not also reguire a Chapter 8.08 street tree planting permit. 
Unless defined in the code, words have their common dictionary definition. 
Standards for tenses and uses are included to add clarity for interpretation o f the code. 
22 
City of'l'ig:ud Urb:-tn h)rc~ lry Code R cYl;-;ion~ I \ 'olun1<.: Ill I 2-t 
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Commentary 
8.02.030 Penalties for Urban Forestry Violations. 
Section 8.02.030 establishes penalties for urban forestry violations which are defined as violations of 
Title 8, Chapter 18.790 and the Urban Forestry Manual. Urban forestry violations are Class 1 civil 
infractions processed according to the procedures in Chapter 1.16. 
Based on community discussions, certain specific urban fore stry violations should have additional 
penalties associated with them so there is a deterrent effect. The specific urban forestry violations 
associated with these additional penalties include unlawful tree removal, unlawful moving, removal 
or damaging tree protection fencing and late or omitted tree protection inspection reports. All three 
of these violations contribute to the removal or damage o f trees and therefore more stringent 
preventative measures are appropriate to deter these violations. 
24 
CitY of Tigord Urban l 'orc> tn· Code RcYisiom I \ "olumc Ill I 2(, 
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Commentary 
8.02.030 Penalties for Urban Fores try Violations. 
The reguirement to receive re troactive approval for tree removal violations allows the city to clearly 
document the removal of pro tected trees, and allows the city to reguire replacement trees when 
applicable. 
The stop work order provision allows the city to prevent continued violation of T itle 8. For 
example, if a pro tected stand of trees in sensitive lands is being cleared without a permit, the city 
may issue a stop work order to prevent continued clearing of the stand. Chapter 1.1 6 does no t 
currently include specific language that allows for stop work orders, so a provision has been added 
to Section 8.02.030 to gran t the city authority to do so for violations of T itle 8. 
26 
Ci11· of Tigord Urbon l' nrc>tn· Code Rcvi>inm I \ 'olumc Il l I 2H 

Commentary 
8.02.040 Administrative Rules- Urban Forestry Manual. 
Section 8.02.040 enables administrative rulemaking for the Urban Forestry Manual which contains 
the detailed administrative rules referenced by Title 8 and Title 18. 
The city manager is authorized to adopt and amend the Urban Forestry Manual according to the 
procedures in Chapter 2.04 after council adoption of Section 8.02.040. 
Section 8.02.040 outlines the specific elements to be included in the Urban Forestry Manual. The 
subsections correspond to the elements contained in the proposed Urban Forestry Manual: 
Subsections of 8.02.040 Urban Forestry Manual Urban Forestry Manual 
Sections Appendices 
A 1 1 
B 2, 3, 4, 5, 6, 7, 8 and 9 2, 3, 4, 5 and 6 
c 10 2, 3, 4, 5, 6, 7, 8 and 9 
D 11 10 
E 12 2, 11 , 12, 13 and 14 
F 13 3, 15, 16, 17and 18 
2K 
CitY of Tigorcl Urban l'orc>t r\' Code Rcl'ioinm I \ 'nlumc Il l I 30 
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Commentary 
8.02.050 D efinition o f Specific Words. 
All tree related definitions in Title 18 have been incorporated into Title 8 to ensure consistency o f 
terms between the two titles. 
The following additional definitions have been developed to address provisions that are specific to 
Title 8. 
Certified Forester: This term is defined because certified fores ters (in addition to certified arborists) 
are permitted by Title 8 and the Urban Forestry Manual to approve the thinning of pro tected stands 
o f trees. 
Significant Tree: This term is added because Chapter 8.16 authorizes designation o f trees as 
significant tree, ra ther than heritage trees when permanent protection is not desirable. 
Thinning: This term is added because thinning of protected stands of trees under the supervision o f 
a certified arborist or certified forester to improve stand health is permitted by Title 8 and the Urban 
Forestry Manual. 
30 
City ofTigorcl Urbon l'orc>tn· Code Rcvi>iom I \ 'olumc Il l I 32 
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F. "Development impact area" - The area on a site or right of way associated with a site 
affected by any and all site or right of way improvements including but not limited to buildings 
structures walls parking and loading areas street improvements paved and graveled areas utilities 
irrigation equipment storage construction parking and landscaping. The impact area also refers to 
areas of grading filling stockpiling demolition tree removal trenching boring and any other 
activities that require excavation or soil disturbance. 
G. "Dripline" - The outer limit of a tree canopy projected to the ground. 
H. "Diameter at breast height (DBH)" The average diameter of the trunk of a tree 
measured 4 1/ z feet above mean ground level at the base of the trunk (see figure 8.02.2). If the tree 
splits into multiple trunks above ground but belmv 4 1/ z feet the DBH is the average diameter of 
the most narrow point beneath the split (see figure 8.02.3). If the tree has excessive swelling at 4 1/z 
feet the DBH is the average diameter of the most narrow point beneath the swelling. If the tree 
splits into multiple trunks at or directly below ground. it shall be considered one tree and the DBH 
4Y:z' ....... . 
Figure 8.02.2 
Standard DBH 
Figure 8.02.3 
DBH for Split Trunk 
I. "Hazard tree related defmitions" 
Figure 8.02.4 
DBH for Multiple Trunks 
1. "Claimant" - Any person that believes in good faith there is a hazard tree on 
a property can demonstrate that their life limb or property has the potential to be impacted by said 
tree and seeks resolution through the Hazard Tree Evaluation and Abatement Procedure specified in 
Section 1 of the Orban Forestry Manual. 
2 " H 
· d . azard tree _ A 
an ll1 ependent certified tree risk ny tree or tree part that has been 
abatement with an overall minim assessor to constitute a high level hazard or <Ould bo dotellllinod b¥ 
tu:os Q! t!« parts r um nsk ranng of 8 for tree reqwnng hazard tree 
· g eater than 4 · h s or tree pa t . than 20 inch oBH .~ me and up to 20 inch DBH'-' up to 1tn<h !21ll:l 2 fur 
d usmg the mo t or IQ fur" eveloped by the Im .' c.uw:nt Ymion o£ the tte . k ~es or tree parts greater 
ernatwnal Society of A b . 1 e ns assessment method 1 r oncu ture. o ogy 
33 
City of Tigard Urban l'orc> try Code Revisions I \'nlume Ill I 35 
Commentary 
8.02.050 Definition of Specific Words. 
Defmitions continued. 
34 
City of'J'ig:ud Urban J.'orc:-;rry Code RcYi sion~ I \ 'ollllnt: I I I I 36 
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Chapter 8.04 T REE P E RMIT PROCED L'RES 
Chapter 8.04 es tablishes a consis tent framework for tree permit decisions that is referenced by all of 
the chapters in Title 8 that require tree permits. 
The guiding principles for Tree Permit Requirements are in Volume I of the legislative adoption 
package for the Urban Forestry Code Revisions. These guiding principles represent the consensus 
view of the citizen advisory committee that advised staff on the Urban Forestry Code Revisions. 
8.04.010 Purpose 
The purpose statement explains that the chapter is intended to provide two tracks for decision 
making. The City Manager D ecision Making Procedures are for simple decisions to be decided by 
staff and the City Board or Committee Decision Making Procedures are for complex decisions to be 
decided by a discretionary review body. 
8.04.020 City Manager D ecision Making Procedures 
T he City Manager Decision Making Procedures are implemented administratively by city staff 
without public review for simple situations such as permitting the planting of street and median 
trees, and permitting the removal of protected trees that are in poor or hazardous condition, 
nuisance trees, causing damage fire dangers or preventing allowed development to occur. 
T he detailed approval criteria in the Urban Forestry Manual are referenced in each chapter o f Title 8 
that requires a tree permit. 
Replacement is required through planting or a fee in lieu when protected trees (except heritage trees) 
are removed. If there is not room on site for a replacement tree, then no fee in lieu is required. 
H eritage trees are not required to be replaced because heritage trees are unique and can not 
necessarily be replaced by planting a new tree. 
411 
CitY of Tigard Urban l 'or~>rrY Code Rc\'t>ions I \ "olumc Ill I -1 2 
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Commentary 
8.04.020 City Manager Decision Making Procedures 
City Manager Decision Making Procedures continued. 
8.04.030 City Board or Committee Decision Making Procedures 
The City Board or Committee Decision Making Procedures are implemented through a public 
review process by a designated board or committee for more complex situations where the reasons 
for removal are unclear (solar access, views, aesthetics, etc.). The designated board or committee is 
authorized to use their discretion to weigh the tree benefits and reasons for removal when making 
their decision. 
The City Board or Committee Decision Making Procedures follow the procedures in Section 
18.390.050 except no pre-application conference (18.390.0SO.A) and no impact study 
(18.390.0SO.B.2.e) is required. 
42 
Cirr ofTigorcl Urbon hnc>tn· Code Rc\'l>ions I \' nlumc Ill I H 
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8.04.040 E mergency Tree Permit Procedures 
l n cases o f emergency, removal of a pro tected tree is authorized without a permit as long as 
retroactive approval through the City Manager D ecision Making Procedures is received. 
44 
CitY ofTigord Urban l'orc> tn· Code Rcn >H>n> I \ 'olumc Ill I 46 
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Commentary 
Chapter 8.06 HAZARD T REES 
The hazard trees chapter creates a framework for addressing hazard trees. 
The guiding principles for Hazard Trees are in Volume I of the legislative adoption package for the 
Urban Forestry Code Revisions. These guiding principles represent the consensus view of the 
citizen advisory committee that advised staff on the Urban Forestry Code Revisions. 
8.06.010 Purpose 
The purpose statement explains that the chapter is to es tablish authority for protecting the public 
from hazard trees through standards and procedures for hazard tree identification, evaluation and 
abatement. 
8.06.020 General Provisions 
H azard trees (defined in Chapter 8.02) are prohibited in T igard. The definition of hazard tree 
incorporates by reference the probability of failure, size of defectiYe part and target area. 
46 
Cin· of 'J'igord Urbon l;orc>trr Code Revt>inm I \ 'nlum<: Ill I 4~ 
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8.06.030 H azard Tree Evaluation and Abatement Procedure 
T he H azard Tree Evaluation and Abatement Procedure is detailed in Section 1 o f the Urban 
Forestry Manual and includes a tiered approach that begins with 1) informal reconciliation between 
parties without city involvement; yet may progress to 2) formal reconciliation where the claimant 
submits an application, provides information, pays fees, documents informal reconciliation and the 
city ensures abatement and apportionment o f costs by private property owners or through city 
action. 
In addition to the procedures being detailed in the Urban Forestry Manual, the city will create more 
user friendly forms that explain the process and timelines. 
A person has standing to participate in the H azard Tree Evaluation and Abatement Procedure only 
if they can demonstrate that they have the potential to be impacted by a tree they believe is a hazard. 
O nce initiated, bo th the claimant and respondent are obligated to complete the Hazard Tree 
Evaluation and Abatement Procedure. 
8.06.040 E mergency Abatement Procedure 
If there is an immediate threa t to public safety, the city has the authority through Chapter 1.16 to 
immediately abate the hazard instead of following the procedures in Section 1 of the Urban Forestry 
Manual. 
4X 
CitY of Tiga rd Urban l'orc,tn · Code RcY~>inns I \'nlumc Ill I SO 
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Commentary 
Chapter 8.08 STREET AND MEDIAN TREES 
Chapter 8.08 establishes the framework for permitting decisions for street and median trees. They 
replace the provisions previously in Chapter 9.06. 
8.08.010 Purpose 
The purpose statement explains the chapter establishes standards and procedures for street and 
median trees to maximize their benefits. 
8.08.020 General Provisions 
Adj acent property owners are responsible for street trees and the city is responsible for median trees. 
The city is authorized to exercise its authority oYer the right of way (and street trees) when 
necessary. 
511 
Cirv of Tigord Urbon l'orc>tn· Cmk R eVISIOn> I Ynlumc Ill I 52 

Commentary 
8.08.020 General Provisions 
General provisions continued (see commentary on previous page). 
8.08.030 Street Tree Planting 
A permit through the City Manager Decision Making Procedures is required for the planting of 
street trees. The detailed planting specifications are in Section 2, part 1 of the Urban Forestry 
Manual. 
8.08.040 Street Tree Maintenance 
Street trees are required to be maintained per tree care industry standards and the clearance 
requirements in Section 2, part 2 o f the Urban Forestry Manual. 
Street trees that die within three years after planting are allowed to be removed and replaced \vithout 
a new permit. It is relatively common for trees to not survive the establishment period, and not 
requiring a permit to remove and replant a newly planted tree that fails to establish improves 
efficiency for both the applicant and city for a relatively insignificant action. 
8.08.050 Street Tree Removal 
Permits obtained through the City Manager Decision Making Procedures or the City Board or 
Committee Decision Making Procedures are required to remove a street tree. 
The approval criteria for street tree removal through the City Manager Decision Making Procedures 
are detailed in Section 3 of the Urban Forestry Manual. 
According to Section 3 o f the Urban Forestry Manual, street tree removal is permitted when: 
1. The tree is a hazard and the hazard cannot be abated without removing the tree. 
2. The tree is dead or declining. 
3. The tree is a nuisance tree. 
4. The tree's location is non-conforming (e.g. closer to an intersection than currently allowed). 
5. The tree roots are causing damage to paved surfaces, buildings or utilities. 
6. Tree removal is required for a street improvement. 
7. Tree removal is required for approved development activities or utili ty installation / repair. 
8. The tree presents a fire or emergency access hazard that cannot be abated without removing 
the tree as determined by the fire marshal. 
9. Tree removal is required for thinning o f a stand o f trees under the supervision o f a certified 
arborist or fore ster. 
Section 3 also requires replacement of street trees when there is room on site unless trees are 
removed for thinning purposes . A fee in lieu o f replacement is allowed at the city's discretion. 
8.08.060 Median Tree Planting 
A permit through the City Manager D ecision Making Procedures is required for the planting o f 
median trees. The detailed planting specifications are in Section 4, part 1 o f the Urban Forestry 
Manual. 
52 
Cit:r of Tig~rd Urbnn l:orc> tn· Code Rcn siom I \ "olumc Ill I 5-I 
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Commentary 
8.08.070 Median Tree Maintenance 
Street trees are required to be maintained per tree care industry standards and the clearance 
requirements in Section 4, part 2 of the Urban Forestry Manual. 
Median trees that die within three years after planting are allowed to be removed and replaced 
without requiring a new permit. It is relatively common for trees to not survive the establishment 
period, and not requiring a permit to remove and replant a newly planted tree that fails to establish 
improves efficiency for both the applicant and city for a relatively insignificant action. 
8.08.080 Median Tree Removal 
Permits obtained through the City Manager Decision Making Procedures or the City Board or 
Committee Decision Making Procedures are required to remove a median tree. 
The approval criteria for median tree removal through the City Manager Decision Making 
Procedures are detailed in Section 5 of the Urban Forestry Manual and are essentially the same 
standards for street tree removal. 
According to Section 5 of the Urban Forestry Manual, median tree removal is permitted \vhen: 
1. The tree is a hazard and the hazard cannot be abated without removing the tree. 
2. The tree is dead or declining. 
3. The tree is a nuisance tree. 
4. The tree's location is non-conforming (e.g. closer to an intersection than currently allowed). 
5. The tree roots are causing damage to paved surfaces, buildings or utilities. 
6. Tree removal is required for a street improvement. 
7. Tree removal is required for approved development activities or utility installation / repair. 
8. The tree presents a fire or emergency access hazard that cannot be abated witl1out removing 
the tree as determined by the fire marshal. 
9. Tree removal is required for thinning of a stand of trees under the supervision of a certified 
arborist or forester. 
Section 5 also requires replacement of median trees, when there is room on site, unless trees are 
removed for thinning purposes. A fee in lieu of replacement is allowed at the city's discretion. 
54 
CitT of Tigo rd Urbon l'nrc>rrr Code RcYi>iom I \ 'olumc II I I 56 
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Chapter 8.10 TREES l N SENSIT IVE LAND S 
Permit requirements for trees in sensitive lands were previously included in Chapter 18.790 (Tree 
Removal) of the Tigard D evelopmen t Code. T he provisions have been struck from Chapter 18.790 
and incorporated into Title 8 for consolidation with the rest of the tree permit provision , for ease o f 
use. 
8.1 0.010 Purpose 
The purpose statemen t explains the chapter and establishes standards and procedures for native 
trees for tl1eir contribution to sensitive lands. 
8.10.020 General Provisions 
Sensitive lands are defined in Chapter 18.775 and include land potentially unsuitable for 
development due to their location in: 
A. Floodplains; 
B. Stream corridors; 
C. Wetlands; 
D . Steep slopes; and/ or 
E. Significant habitat areas. 
A map of sensitive lands is maintained by the city and is used to determine whether a tree is within 
sensitive lands. T his negates the requirement for a detailed delineation if the city and applicant agree 
whether a tree is wiiliin sensitive lands or no t. A detailed delineation could be provided to the city 
to prove the exact location o f a tree in relation to sensitive lands if the map boundaries are not 
accep table. 
5(, 
Ci ty of Tig:u d Urb3n ( .'nrc~l ry Code 1\ c.:nsinns I \ 'o lun1c: Ill 1 5 ~ 

Commentary 
8.1 0.020 G eneral Provisions (continued) 
O nly trees on the native tree list in the Urban Forestry Manual are subject to the provisions o f the 
chapter. 
8.1 0.030 Sensitive Lands Tree Maintenance 
Native trees over 6 inch DBH and required replacement trees (which can be less than 6 inch DBH) 
in sensitive lands are required to be maintained per tree care industry standards. 
T he removal and replacement o f trees in sensitive lands is allowed for required trees that die within 
three years after planting. It is relatively common for trees to not survive the es tablishment period, 
and not requiring a permit to remove and replant a newly planted tree that fails to es tablish improves 
efficiency for both the applicant and city for a relatively insignificant action. 
8. 10.040 Sensitive Lands Tree Removal 
Permits obtained through the City Manager D ecision Making Procedures or the City Board or 
Committee D ecision Making Procedures are required to remove protected trees in sensitive lands. 
The approval criteria for sensitive lands tree removal through the City Manager D ecision Making 
Procedures are detailed in Section 6 o f the Urban Forestry Manual. 
According to Section 6 o f the Urban Forestry Manual, sensitive lands tree removal is permitted 
when: 
1. The tree is a hazard and the hazard cannot be abated without removing the tree. 
2. The tree is dead or declining. 
3. The tree is a nuisance tree. 
4. The tree roots are causing damage to paved surfaces, buildings or utilities. 
5. Tree removal is required for a street improvement. 
6. Tree removal is required for approved development activities or utility installation / repair. 
7. The tree presents a fire or emergency access hazard that cannot be abated without removing 
the tree as determined by the fire marshal. 
8. Tree removal is required for thinning o f a stand o f trees under the supervision o f a certified 
arborist or forester. 
Section 6 also requires replacement o f trees in sensitive lands, when there is room on site, unless 
trees are removed for thinning purposes. In addition to newly planted trees, existing trees less than 
6 inch DBH can be used as replacement trees provided they meet all o f the replacement tree species, 
size, condition and location standards detailed in Section 6. A fee in lieu of replacement is allowed 
at the city's discretion. 
sx 
Ci11· of T igord Urbon h>rc>trr Code Ren>inm I \ 'olumc Ill I (> I I 

Commentary 
Chapter 8. 12 TREES THAT WERE REQUIRE D WITH D EVELOPMENT 
Chapter 8. 12 establishes the framework for permitting decisions for trees that were required to be 
planted or preserved by a land use permit when the removal is not associated with an active land use 
permit. The intent of the legislative amendments in Chapter 8.12 is to supersede the planting and 
preservation requirements for trees that were required by prior land use decisions. This includes 
trees that are recorded as preserved on property deeds as a result of past land use decisions. 
However, for these deed restricted trees, applicants (and not the city) will be solely responsible for 
identifying and removing any applicable deed restrictions. The city will provide any signatures 
necessary to facilitate the removal of deed restrictions for trees permitted for removal by decisions 
pursuant to Chapter 8.12. 
8.12.010 Purpose 
The purpose statement explains that the chapter establishes standards and procedures for trees that 
were required with development to maintain their benefits after the development process is 
complete. 
8.12.020 General Provisions 
The provisions of Chapter 8. 12 apply to trees required to be planted or preserved by a land use 
permit and trees that are required as replacements for said trees. 
The city retains records of all land use permits. These records will be used to determine whether a 
tree was required to be planted or preserved by a land use permit. If there is not a clear record, the 
tree will be exempt from Chapter 8.12. 
(>(I 
City of 'J'ig:1.rd Urban 1--'orc:-;rry Code 1\cyi:-; ion:-; I Y nlun1c Ill I (J 2 
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8.12.030 Maintenance o f Trees That Were Requited With D evelopment 
Trees that were requited to be planted or preserved by a land use permit are requited to be 
maintained per tree care industry standards. 
The removal and replacement o f trees subject to the provisions o f this chapter is allowed for trees 
that die within three years after planting. It is relatively common for trees to no t survive the 
es tablishment period, and no t requiring a permit to remove and replant a newly planted tree that 
fails to es tablish improves efficiency for bo th the applicant and city for a relatively insignificant 
action. T ree es tablishment associated with an active land use permit is administered through the 
corresponding regulations for that permit (e.g. Chapter 18.790). 
8.12.040 Removal of Trees That Were Required With Development 
Permits obtained through the City Manager D ecision Making Procedures or the City Board or 
Committee D ecision Making Procedures are requited to remove trees requited to be planted or 
preserved by a land use permit. 
The approval criteria for "development" tree removal through the City Manager D ecision Making 
Procedures are detailed in Section 7 o f the Urban Forestry Manual. 
According to Section 7 o f the Urban Forestry Manual, development tree removal is permitted when: 
1. The tree is a hazard and the hazard cannot be abated without removing the tree. 
2. The tree is dead or declining. 
3. The tree is a nuisance tree. 
4. The tree roots are causing damage to paved surfaces, buildings or utilities. 
5. Tree removal is requited for a street improvement. 
6. T ree removal is required for approved development activities or utili ty installation / repair. 
7. T he tree presents a fire or emergency access hazard that cannot be abated without removing 
the tree as determined by the fire marshal. 
8. Tree removal is requited for thinning o f a stand o f trees under the supervision of a certified 
arborist or fores ter. 
Section 7 also requites replacement of development trees, when there is room on site, unless trees 
are removed for thinning purposes. Replacement trees are required to be o f equivalent stature and 
location so as to replace the function of the tree that was removed. For example, if a tree was 
requited by Chapter 18.7 45 to provide a buffer between properties, it is requited to be replaced with 
a similar stature tree (at maturity) and similar location so that it can continue to provide a buffering 
effect. In addition to newly planted trees, existing trees can be used as replacement trees provided 
they meet all of the replacement tree species, size, condition and location standards detailed in 
Section 7 and are no t already pro tected by o ther code provisions. A fee in lieu o f replacement is 
allowed at the city's discretion. 
62 
City of'J'igord Urbon l;orC>< In· Code Rcn>'!om I \ "nlume: Ill I (i .J 
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Chapter 8. 14 TREES THAT WERE PLANTED USING THE URBAN FORESTRY FUND 
Chapter 8.14 establishes the framework for permitting decisions for trees that were planted using the 
Urban Forestry Fund. 
8.14.010 Purpose 
The purpose statement explains that the chapter creates standards and procedures for maintaining, 
removing and replacing trees that were planted using the city's Urban Forestry Fund. The chapter is 
intended to ensure maximum benefit when city funds are expended to plant trees. 
64 
CitY of ' l'ig"cl Urban l:orc> tr\· Code Rc\'l>inm I \ 'nlumc Ill I 66 
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Commentary 
8.14.020 General Provisions 
The provisions are applicable to trees planted using the Urban Forestry Fund. O nly those trees 
planted after the date of adoption of the Urban Fores try Code Revisions will be subj ect to the 
provisions of the chapter, since prior plantings were undertaken without knowledge o f the code 
requirements. 
The city records o f planting projects will be used to determine if a particular tree was planted using 
the Urban Forestry Fund. 
8.14.030 Maintenance o f Trees that were Planted Using the Urban Forestry Fund 
Trees that were planted using the Urban Forestry Fund are required to be maintained per tree care 
industry standards. 
The removal and replacement of trees that were planted using the Urban Fores try Fund is allowed 
for trees that die within three years after planting. It is relatively common for trees to no t survive 
the es tablishment period, and no t requiring a permit to remove and replant a newly planted tree that 
fails to establish improves efficiency for bo th the applicant and city for a relatively insignificant 
action . 
8. 14.040 Removal o f Trees that were Planted Using the Urban Forestry Fund 
Permits obtained through the City Manager D ecision Making Procedures or the City Board or 
Committee Decision Making Procedures are required to remove trees that were planted using the 
Urban Fores try Fund. 
T he approval criteria for "Urban Fores try Fund" tree rem oval through the City Manager Decision 
Making Procedures are detailed in Section 8 o f the Urban Forestry Manual. 
According to Section 8 o f the Urban Forestry Manual, Urban Forestry Fund tree removal is 
permitted when: 
1. T he tree is a hazard and the hazard cannot be abated without removing the tree. 
2. The tree is dead or declining. 
3. The tree is a nuisance tree. 
4. The tree roots are causing damage to paved surfaces, buildings or utilities. 
5. T ree removal is required for a street improvement. 
6. Tree removal is required for approved development activities or utili ty installation / repair. 
7. The tree presents a fire or emergency access hazard that cannot be abated without removing 
the tree as determined by the fire marshal. 
8. T ree removal is required for thinning of a stand o f trees under the supervision o f a certified 
arborist or fores ter. 
Section 8 also requires replacement o f Urban Fores try Fund trees when there is room on site unless 
trees are removed for thinning pm1Joses. Replacement trees are required to be o f equivalent stature 
so as to replace the future canopy o f the tree that was removed. In addition to newly planted trees, 
exis ting trees can be used as replacement trees provided they meet all o f the replacement tree 
species, size, condition and location standards detailed in Section 8 and are no t already pro tected by 
o ther code provisions. i\ fee in lieu o f replacement is allowed at the city's discretion . 
(>(, 
CitY ofTigorc! L'rbon l'orc>t n· Code Rc,·isions I \ 'olumc Ill I 61< 
0 ...
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Commentary 
8. 16.010 Purpose 
The purpose statement explains that the chapter creates a framework for recognizing, appreciating 
and providing voluntary pro tection for trees of landmark importance. 
(>H 
CitY ofTigord Urban l'orc>tn- Code Rc\'l>iom I \ 'nlumc II I I 711 
c a- " :1 < " c 3 r. 
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. 
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Commentary 
8.16.020 General Provisions 
The city \Vill designate a board or commission to administer the chapter provisions. 
Trees may be granted one of two special designations Q1eritage tree or significant tree) by the 
provisions of this chapter. Heritage trees are of landmark importance, afforded regulatory 
protection from removal and eligible for city funding for maintenance. Significant trees are also o f 
landmark importance, are not afforded regulatory protection from removal and are not eligible for 
city funding for maintenance. 
The reviewing authority may decide a tree that is nominated as a heritage tree should be designated 
as a significant tree if it is of lesser landmark importance (than a heritage tree). An applicant may 
nominate a tree directly for designation as a significant tree if they acknowledge a particular tree is o f 
lesser landmark importance, but they would still like ilie tree to be recognized by the community. 
Alternatively, an applicant may nominate a tree for significant tree designation if they do not want 
the tree to be afforded regulatory protection, even if they think the tree could be designated as a 
heritage tree. 
7 11 
Cin· o f Tigorcl Urbon l'orc> tr\' Code RcYi>iom I \ 'nlumc II I I 72 
<
 
0 c 3 " 
Commentary 
8.16.030 Nomination and D esignation of H eritage Trees 
T he process of nominating and designating a heritage tree begins \vith someone recognizing that a 
tree or group o f trees is of landmark importance due to age, size, species, horticultural quality or 
historic importance. The tree owner is required to sign o ff on the nomination. If the tree owner is 
the city, the city manager or designee is required to sign off on the nomination. 
T he designated city board or committee then reviews the nomination materials and can decide to 
recommend heritage tree designation and forward their decision to City Council, approve 
designation as a significant tree subject to final approval of the proper ty owner or deny the tree 
designation as a heritage tree or significant tree. 
If the designated city board or committee recommends heritage tree designation, th e city will 
prepare the necessary paperwork to record heritage tree designation on the property deed . The 
proper ty owner will be required to sign the paperwork in advance o f City Council's final decision on 
the heritage tree. T his is a change from current procedures in Chapter 9.08 because there have been 
instances in the pas t where, after council voted to approve heritage tree designation, the applicant 
decided they did not want to sign the paperwork. Under the new procedure, the city would destroy 
the signed paperwork if City Council does not approve heritage tree designation. 
After the necessary paperwork is signed, City Council will review the nomination materials and 
recommendations by staff and the designated board or commission. City Council may vote to 
approve heritage tree designation (at which point the heritage tree paperwork will be executed for 
recording on the deed o f the property), approve significant tree designation (subject to final 
approval o f the property owner) or deny the tree heritage or significant tree designation. 
Trees that are designated as heritage trees or significant trees will be included in a publicly accessible 
inventory o f trees. 
72 
City ofTig~rd Urb:1n f.'ores try Code Rc\'lsinn!' I \ ·olun1e Ill I 7-1 
<
 
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Commentary 
8.16.030 Nomination and D esignation of Heritage Trees 
Nomination and designation provisions continued. 
8. 16.040 Maintenance o f H eritage Trees 
Heritage trees are required to be maintained per tree care industry standards. 
8.16.050 Nomination and D esignation o f Significant Trees 
Trees can be nominated for significant tree designation directly with the tree owner's approval. 
T he designated board or commission will review the nomination and will decide whether to approve 
or deny designation. 
Following approval, significant trees are included on a publicly accessible inventory o f trees. 
Significan t trees do not have regulatory protection. 
74 
CiiY nf'J'igord Urbon l 'orc>~n· Code Rcvt>inns I \"olumc Ill I 76 

Commentary 
8. 16.060 Incentives for Heritage Tree D esignation 
D esignated heritage trees are eligible for incentives such as plaques and maintenance subject to the 
availability o f funds. Significant trees are no t eligible for such incentives because regulatory 
pro tections for the trees are no t in place. 
7(> 
CitY of Tigorcl Urbon l'orc> trY Code ReY~>iom I \" olumc Ill I 71< 
c ;;. " " 
IP
' I
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Commentary 
8. 16.070 Removal of H eritage Tree D esignation 
Permits obtained through the City Manager D ecision Making Procedures or the City Board or 
Committee D ecision Making Procedures are required to remove heritage tree designation . 
The approval criteria for heritage tree designation removal through the City Manager D ecision 
Making Procedures are detailed in Section 9 of the Urban Forestry Manual. 
According to Section 9 of the Urban Forestry Manual, removal o f heritage tree designation is 
permitted when: 
1. T he tree is a hazard and the hazard cannot be abated without removing the tree. 
2. T he tree is dead or declining. 
3. T he tree presen ts a fire or emergency access hazard that cannot be abated without removing 
the tree as determined by the fire marshal. 
4. Tree removal is required for thinning o f a stand o f heritage trees under the supervision of a 
certified arborist or forester. 
There is less criteria that would allow the removal of heritage trees through the City Manager 
D ecision Making Procedures than the o ther pro tected classes o f trees since heritage trees are of 
special significance. For example, if a street tree has roots damaging a sidewalk it would be 
approved for removal by the city without public review, whereas the removal o f a heritage tree with 
roots damaging a sidewalk \vould only be permitted following a public review (City Board or 
Committee D ecision Making Procedures). Through the public review, the public could weigh things 
like whether the sidewalk could be repaired in a way that preserves the tree, the importance o f the 
tree to the surrounding community and the impact of the tree on the owner. 
Section 9 does not require replacement o f heritage trees because heritage trees are unique and can 
not necessarily be replaced by planting a new tree. 
O nce heritage tree designation is removed, the tree is no longer subject to the chapter provisions. 
7~ 
CitY ofTigord U rb~n l'orc< rrv Code RcYi<inm I \ 'olumc Ill I llO 

Commentary 
Chapter 9.06 TREES ON CITY PROPERTY. 
The provisions of Chapter 9.06 have been struck so there are consistent regulations across 
ownerships. In other words, the same standards will apply regardless of whether trees are on city 
property or private property. 
Definitions in Chapter 9.06 have been revised and relocated to Chapters 8.02 and 18.120. 
The Tree Manual has been revised and is now the Urban Foresu-y Manual which is referenced in 
Section 8.02.030. 
Provisions in Chapter 9.06 that are specific to street trees have been revised and relocated to 
Chapter 8.08. 
Provisions in Chapter 9.06 that are specific to development are located in Chapter 18.790. 
Enforcement provisions in Chapter 9.06 specific to trees are now in Sections 8.02.030 and 1.16.640. 
HI I 
Ciil' o f 'J'igord Urbon l;nrc>trl' Cndc Rcl' i>inm I \ 'olumc II I I H2 
c§ a. c a- " ::l 
cc
 
Commentary 
Chapter 9.06 TREES ON CITY PRO PERTY. 
Strikethroughs of existing trees on city property provisions continued. 
X2 
CitY of'J'igorcl Urbon h>rc>tn· Code Rcvi>inm I \ 'olumc Il l I H-t 

Commentary 
Chapter 9.06 TREES ON CITY PROPERTY. 
Strikethroughs of existing trees on city property provisions continued. 
~4 
Cir,· ofTigord Urbon l'nrc>trY Code RcYi>ion> I \ 'olumc Ill l llo 
<
 
0 c 3 " 
Commentary 
Chapter 9.06 TREES ON CITY PROPE RTY. 
Strikethroughs of existing trees on city property provisions continued. 
}((, 
CitY ofTigorcl Urbon 1:orc"n· Code Revision> I \'olumc Ill I HX 

Commentary 
Chapter 9.06 TREES O N CITY PRO PE RTY. 
Strikethroughs of existing trees on city property provisions continued. 
HH 
Ci tY of'J'igorcl Urbon l' nrc> trY C ode RcYisiom I \'olum c I ll I 90 

Commentary 
Chapter 9.08 H E RITAGE TREES 
Chapter 9.08 contains the exis ting provisions for heritage tree designation , maintenance, removal 
and enforcement. The heritage tree provisions have been revised and moved to Chapter 8.16 
(Heritage Trees) in the new consolidated Urban Forestry Title 8. 
T he revised heritage tree provisions allow for designation of two types o f landmark trees (heritage 
trees and significant trees). The significant tree designation is new and allows for recognition o f 
trees that are either o f lesser landmark importance and / or the tree owner does not want regulatory 
protections for the tree. 
<J(I 
Citl' ofTig>rd Urbon l'ore> tn Code 1\e\'l>inns I \ ·olume Il l I 92 

Commentary 
Chapter 9.08 HE RITAG E TREES 
Strikethroughs of existing heritage tree provisions continued. 
'!2 
CitY of Tigard Urban l'nrc> trr Code Rc" i>iom I \ 'nlumc Ill I 9-1 

Commentary 
Chapter 9.08 H ERITAGE TREES 
Strikethroughs of existing heritage tree provisions continued. 
'14 
Cify of 'J'ig:1rd Urb:1n l ; orc~ [ry Code H.cv i ~ion~ I \ 'nlwnc Ill I 96 
<
 
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[ 
Commentary 
Chapter 9.08 HERITAGE TREES 
Strikethroughs of existing heritage tree provisions continued. 
% 
City of'J'ig:1rd Urban l;on:stry Code Rcnsions I \ 'nlunlt: I ll I {_}!-( 

City of Tigard 
COMMUNITY DEVELOP~ifENT DEPARTMENT 
13125 SW Hall Blvd., Tigard, OR 97223 
www. tigard-or.gov / trees I 
Volume IV: Table of Contents 
Organization of the Urban Forestry Code Revisions Documents 
Urban Forestry Manual 
1 
3 
Table of Contents ................................. ... ........ ....... ... ............................................. .. ... .......... ... ...... .... .......... . 5 
Section 1 - Hazard Tree Evaluation and Abatement Procedure .......... ....... ... .......... .... ...... .... ......... ....... 9 
Section 2 - Street Tree Planting and Maintenance Standards 
Section 3- Street Tree Removal Standards 
Section 4 - Median Tree Planting and Maintenance Standards 
11 
5 
17 
Section 5- Median Tree Removal Standards .......................................................................................... 21 
Section 6 - Sensitive Lands Tree Removal and Replacement Standards ....................... .......... ..... .. ..... 23 
Section 7 - Development Tree Removal and Replacement Standards .... .. ..... .. .............................. ..... 27 
Section 8- Urban Forestry Fund Tree Removal and Replacement Standards ............ ................... .. . 31 
Section 9 - Heritage Tree Designation and Removal Standards .......................................................... 35 
Section 10 - Urban Forestry Plan Standards .................................................................................. .. ....... 37 
Section 11 -Urban Forestry Plan Implementation Standards ................... ........ ......... ........ ................. .49 
Section 12 - Street Tree Soil Volume Standards ................. ... .. ..... .. ...................... ... .. ................ ... .......... 53 
Section 13 - Parking Lot Tree Canopy Standards ......... ..... ........................................ ............. ............... 51 
Appendices ...... .................. .. ............ ....... .. ..... ....... ........................................................................................ 61 
Organization ofthe Urb an Forestry Cod e Revisions D ocuments 
The Urban Forestry Code Revisions project is presented in five volumes. Volume I provides the 
project overview and describes the process used to develop all of the elements. Volume II is the 
land use elements of the code, and Volume III the non land use elements. Volume IV contains the 
Urban Forestry Manual. Volume V contains technical reports and research that contributed to the 
code revisions along with details of the public input and deliberations to date. 
Volume I I Project Overview 
Project Overview includes the following sections: 
• Project Introduction 
• Overview of Key Elements 
• Key Element Summaries 
o Urban Forestry Standards for D evelopment 
o Tree Grove Preservation Incentives 
o Tree Permit Requirements 
o Hazard Trees 
o Urban Forestry Manual 
Appendix A includes additional detail about the information used to shape the Urban 
Forestry Code Revisions Project, and includes the following sections: 
• Process summary 
• Summary of Community Ideas and Concerns 
• Summary of Planning Commission D eliberations 
• Exis ting Conditions 
Volume II I Land U se Elements 
Community Development Code (Title 18) is the Planning Commission's recommended 
draft of the D evelopment Code. This section includes commentary on the amendments. 
P eer Review demonstrates how the Planning Commission's recommended draft of the 
D evelopment Code and Urban Forestry Manual will work in application. 
Tree Grove ESEE Analysis is a report that addresses Statewide Planning Goal 5- Natural 
Resources requirements for the preservation of Significant Tree Groves. 
Staff Report and findings includes the staff recommendation for approval of the land use 
elements (ritle 18 and the Comprehensive Plan Amendment) and the findings that 
demonstrate the land use elements meet the necessary approval criteria. 
City o f Tigard Urban l'o rc~try Code Rc,·isions I Volume IV I 1 
Volume III I Non Land Use Elements 
Tigard Municipal Code is the staff proposed draft of the Municipal Code (Title 8 and 
other Municipal Code titles). This section includes commentary on the amendments. 
Volume IV I Urban Forestry Manual (Administrative Rules) 
Urban Forestry Manual consists o f administrative rules that implement the technical 
details of the urban forestry related code provisions in Title 8, Title 18 and other applicable 
titles in the Tigard Municipal Code. 
Volume V I Additional Background Materials 
Planning Commission Deliberations details Planning Commission discussion and 
decisions during the public hearing process. 
Amendment Requests Document for the Planning Commission lists code amendment 
requests received in response to the first Planning Commission public hearing and staff 
responses . 
Outstanding Issues for the Urban Forestry Code Revisions includes additional 
information on the outstanding issues that were further deliberated by the Planning 
Commission before making their final recommendation to City Council on May 7, 2012. 
Log of Input lists the input received and any code changes from the last meeting of the 
CAC to the staff proposed draft of the Urban Forestry Code Revisions to Planning 
Commission. 
CAC Guiding Principles includes the consensus view of the Citizens Advisory Committee 
(CAC) developed to help guide the legislative adoption process . 
Tree Values includes information and current research on the environmental, economic, 
social and aesthetic benefits of trees. 
Canopy Standards explains the reasons for adopting tree canopy cover requirements as 
well as the methods used to arrive at the requirements. 
Soil volume details research about the soil volume required to support a mature tree 
canopy. 
Tree Canopy Fee discusses research used to develop a square foot value for tree canopy. 
Regulatory Comparison is an excerpted report prepared by Metro and the 1\udubon 
Society that sutrunarizes and compares regional urban forestry programs and regulations. 
Urban Forestry Master Plan is the City of Tigard's recotrunended plan for achieving the 
urban forestry goals in the Comprehensive Plan. 
City of 'J'igan.l Urban l;orc> try Co de RcY i>iom I \'olumc I\ ' I 2 
City offigard 
URBAN FORESTRY MANUAL 
Introduction 
The Urban Forestry Manual consists of administrative rules that implement the details of the urban 
forestry related code provisions in Title 8, Title 18 and other applicable titles in the Tigard Municipal 
Code. 
The city manager or designee has the authority to amend the Urban Forestry Manual pursuant with 
the provisions in Chapter 2.04 of the Tigard Municipal Code. The city manager or designee is 
authorized to administer the Urban Forestry Manual. 
City of Tigard Urban Forestry Code ReYisions I Volume IV I 3 
2 
.? 
TABLE OF CONTENTS 
Section 1 ........................................ Hazard Tree Evaluation and Abatement Procedure 
Section 2 ............................................ Street Tree Planting and Maintenance Standards 
Section 3 ......................................................................... Street Tree Removal Standards 
Section 4 ......................................... Median Tree Planting and Maintenance Standards 
Section 5 ..................................................................... Median Tree Removal Standards 
Section 6 ........................... Sensitive Lands Tree Removal and Replacement Standards 
Section 7 ............................... Development Tree Removal and Replacement Standards 
Section 8 .................. Urban Forestry Fund Tree Removal and Replacement Standards 
Section 9 ....................................... Heritage Tree Designation and Removal Standards 
Section 10 ....................................................................... Urban Forestry Plan Standards 
Section 11 ............................................ Urban Forestry Plan Implementation Standards 
Section 12 ................................................................. Street Tree Soil Volume Standards 
Section 13 .............................................................. Parking Lot Tree Canopy Standards 
City of Tigard Urban l'orcs try Code Rc1·isions I Volume 1\' I 5 

APPENDICES 
Appendix 1 ......................................................................... Tree Risk Assessment Form 
Appendix 2 .................................................................. ............ .... ............ Street Tree List 
Appendix 3 ............... ..... ..... .. .. ................ .......................... ............. Parking Lot Tree List 
Appendix 4 ....................................................................................... Columnar Tree List 
Appendix 5 ............................................................................................ Native Tree List 
Appendix 6 ....................................................................................... Nuisance Tree List 
Appendix 7 ..................................... Example Tree Preservation and Removal Site Plan 
Appendix 8 ................................................................... Example Tree Canopy Site Plan 
Appendix 9 .................................................... Example Supplemental Report Template 
Appendix 10 ............................... Example Tree Canopy Site Plan for an Individual Lot 
Appendix 11 ................................... Example Soil Volume Calculations for Street Trees 
Appendix 12 .......................................................................... Example Soil Volume Plan 
Appendix 13 ................................................ Example Soil Volume Plan for a Single Lot 
Appendix 14 .................................... Example Covered Soil Volume Plan Drawings and 
Example Covered Soil Specifications for Street Trees 
Appendix 15 ......................... Example Soil Volume Calculations for Parking Lot Trees 
Appendix 16 .................................................... Example Parking Lot Tree Canopy Plan 
Appendix 17 .................................... Example Covered Soil Volume Plan Drawings and 
Example Covered Soil Specifications for Parking Lot Trees 
Appendix 18 ................................. Example Parking Lot that Meets the 30% Minimum 
Canopy Cover Requirement 
City of Tigard Urban Forestry Code Re,·isions I Volume IV I 7 

Section 1 - Hazard Tree Evaluation and Abatement Procedure 
Part 1. Informal Reconciliation: 
If interpersonal communication is not feasible or is unsuccessful, the 
clain1ant shall contact the respondent by concurrently sending a 
regular and certified letter that explains the reasons they believe there 
is a hazard tree on the respondent's property, demonstrates how the 
claimant's life, limb or property has the potential to be impacted by 
said tree, and offers to negotiate a solution that is in compliance with 
all applicable rules and regulations either directly or tluough a third 
party mediator. The claimant is encouraged to support their claim 
with documentation by a certified tree risk assessor. The respondent 
shall have seven calendar days or less from receipt of the certified 
letter or 14 calendar days or less from the postmarked date of the 
regular letter (whichever is sooner) to respond to the claimant's 
proposal in writing by concurrent regular and certified mail. In order 
to become eligible for formal reconciliation, the claimant's letter shall 
cite Tigard Municipal Code sections 8.06.020 and 8.06.030, explain the 
respondent's written response deadlines and include all of the other 
required elements listed above. 
Part 2. Formal Reconciliation: 
If the results of informal reconciliation are not acceptable to the 
claimant or there has been no response for 21 calendar days or more 
since the claimant sent the concurrent regular and certified letters, the 
claimant may seek resolution tluough formal reconciliation by 
completing a hazard tree dispute resolution application, paying a 
deposit for all applicable hazard tree dispute resolution fees and 
providing the city all documentation of informal reconciliation 
including but not limited to any letters to and from the respondent, 
proof of certified mail delivery and proof of certified mail receipt (if 
available). 
The city shall use all readily available tools and technology when 
assigning the hazard tree owner or responsible party as defined in 
Tigard Municipal Code Chapter 8.02. If the city determines that the 
claimant's previous correspondence was with the incorrect 
respondent, then the claimant shall be required to complete the 
previous steps of the hazard tree evaluation and abatement procedure 
with the correct respondent before proceeding with formal 
reconciliation. If the claimant or respondent disagrees with the city's 
assignment of the hazard tree owner or responsible party, the city shall 
be presented a land survey by a professional land surveyor that 
demonstrates the location of the tree in question in relation to 
property lines within all listed deadlines in order for the city to 
consider a reassignment of the hazard tree owner or responsible party. 
Notes: 
See Master Fees and 
Charges Schedule for 
current fees 
S e c t i o n 1 - H a z a r d T r e e E v a I u a t i o n a n d A b a t e m e n t P r o c e d u r e Page 1-1 
City of Tigard Urban Forestr y Manual 
- -- --- -- -
Cit)' of Tigard Urban Forestry Code Rc,·isions I Volume I\' I 9 
N otes: 
Sec 1\ppendix 1 for 
Tree Risk 
t\ssessment Form 
Page 1-2 
Within seven calendar days of receipt of all the required application materials, 
the city shall gain access to the respondent's property either voluntarily or with 
a warrant pursuant to Chapter 1.16 of the Tigard Municipal Code, conduct a 
tree risk assessment by a certified tree risk assessor using the most current 
version of the tree risk assessment methodology developed by the International 
Society of Arboriculture, determine if the definition of hazard tree in Tigard 
Municipal Code Chapter 8.02 has been met and, if necessary, prescribe hazard 
tree abatement as defined in Tigard Municipal Code Chapter 8.02. 
If the city determines the definition of hazard tree has been met, the city shall 
send a concurrent regular and certified letter to the respondent, explain that the 
definition of hazard tree has been met, explain the required hazard tree 
abatement procedures and require that hazard tree abatement be completed in 
seven calendar days or less from receipt of the certified letter or 14 calendar 
days or less from the mailing date of the regular letter (whichever is less). The 
city shall also bill the respondent for all applicable hazard tree dispute 
resolution fees, and refund the claimant previously deposited hazard tree 
dispute resolution fees. 
If the respondent fails to complete the hazard tree abatement within the 
required timeframe, the city shall gain access to the property either voluntarily 
or with a warrant, abate the hazard, bill the respondent for the cost of 
abatement including administrative costs or place a lien on the property for the 
cost of abatement including administrative costs pursuant to Chapter 1.16 of 
the Tigard Municipal Code. 
If the city determines the definition of hazard tree has not been met, the city 
shall send a concurrent regular and certified letter to both the claimant and 
respondent explaining that the definition of hazard tree has not been met and 
close the case. 
END OF SECTION 
Section 1- Hazard Tree Evaluation and Abatement Procedure 
City of Tigard Urban Forestry Manual 
CitY of Tiga rd Urban Forestry Code RcYisions J \'olumc I\ ' J ] () 
Section 2 - Street Tree Planting and Maintenance Standards 
Part 1. 
A. 
B. 
c. 
D . 
Street Tree Planting Standards: 
Street trees shall be planted in a manner consistent with tree care 
industry standards. 
Street trees shall have a minimum caliper of 1 Vz inches at the time of 
planting. 
Street tree species shall be from the street tree list, unless otherwise 
approved by the city manager or designee. 
Street tree species shall be appropriate for the planting environment as 
determined by the city manager or designee and seek to achieve a 
balance of the following: 
1. Consistency with previously approved street tree plans given 
space constraints for roots and branches at maturity; 
2. Compatibility with space constraints for roots and branches at 
maturity; 
3. Providing adequate species diversity citywide and reasonable 
resistance to pests and diseases; and 
4. Consideration of the objectives of the current street tree 
planting proposal. 
E. Street trees shall be provided adequate spacing from new and existing 
trees according to the following standards wherever possible: 
1. Street trees categorized as small stature on the street tree list or 
by the city manager or designee shall be spaced no greater than 
20 feet on center and not closer than 15 feet on center from 
other newly planted street trees or any existing tree that has 
been in the ground for over three years; 
2. Street trees categorized as medium stature on the street tree list 
or by the city manager or designee shall be spaced no greater 
than 30 feet on center and not closer than 20 feet on center 
from other newly planted street trees or any existing tree that 
has been in the ground for over three years; 
3. Street trees categorized as large stature on the street tree list or 
by the city manager or designee shall be spaced no greater than 
40 feet on center and not closer than 30 feet on center from 
other newly planted street trees or any existing tree that has 
been in the ground for over three years; and 
4. Any tree determined by the city manager or designee to have a 
mature spread of less than 20 feet shall be considered a small 
stature tree, and spaced accordingly when used as a street tree. 
F. Street trees shall be placed according to the following standards: 
Section 2- Street Tree Planting and Maintenan ce Standards 
City of Tigard Urban Forestry Manual 
- -~·-- -
City of Tigard Urban Forestry Code Rc,·isiom I Volume IV I 11 
Notes: 
See Appendix 2 for 
Street Tree List 
Page 2-1 
------ - ----
Norc~: 
Sec Code Section 
8.08 and l\lanual 
Section 3 for Street 
Tree Removal 
Standa.rds 
Sec Master Fees and 
Charges Schedule for 
cu rrcn t fees 
Page 2-2 
1. 
2. 
3. 
4. 
5. 
6. 
7. 
Street trees categorized as small stature on the street tree list 
or by the city manager or designee shall not be planted with 
the center of their trunks closer than 2 feet from any hard 
surface paving; 
Street trees categorized as medium stature on the street tree 
list or by the city manager or designee shall not be planted 
with the center of their trunks closer than 2 Vz feet from any 
hard surface paving; 
Street trees categorized as large stature on the street tree list 
or by the city manager or designee shall not be planted with 
the center of their trunks closer than 3 feet from any hard 
surface paving; 
Not closer than 4 feet on center from any fire hydrant, utility 
box or utility pole; 
Not closer than 2 feet on center from any underground 
utility; 
Not closer than 10 feet on center from a street light standard; 
Not closer than 20 feet from a street right of way corner as 
determined by the city manager or designee. The city 
manager or designee may require a greater or lesser corner 
setback based on an analysis of traffic and pedestrian safe ty 
impacts; 
8. Where there are overhead utility lines, the street tree species 
selected shall be of a type which, at full maturity, will not 
interfere with the lines; and 
9. Any other standards found by the city manager or designee to 
be relevant in order to protect public safety and public or 
private property. 
G. Root barriers shall be installed according to the manufacturer's 
specifications when a street tree is planted within 5 feet of any hard 
surface paving or utility box, or as otherwise required by the city 
H . 
I. 
engmeer. 
Street trees planted prior to the adoption of the most current version 
o f the street tree planting standards shall be exempt from the most 
current version of the street tree planting standards. However, the 
most current version of the street tree maintenance standards and the 
most current version of the street tree removal standards shall apply. 
If street tree planting is required by another section of the Urban 
Forestry Manual or Tigard Municipal Code, the city manager or 
designee may allow for an "in lieu of planting fee" equivalent to the 
city's cost to plant a street tree per the standards in Section 2, part 1 of 
the Urban Forestry Manual and maintain a street tree per the standards 
in Section 2, part 2 of the Urban Forestry Manual for a period of three 
years after planting. Payment of an in lieu of planting fee shall satisfy 
the street tree planting requirement. 
Section 2 - Street Tr ee Planting and Maintenance Standards 
City of Tigard U rb an Forestr y Manual 
City of Tigard Urban l ;or~stn· Code Rc,·isions I \ 'olumc I\ ' I 12 
Part 2. Street Tree Maintenance Standards: 
A. Street trees shall be maintained in a manner consistent with tree care 
industry standards. 
B. Street trees shall be maintained in a manner that does not impede 
public street or sidewalk traffic consistent with the specifications in 
section 7.40.060A of the Tigard Municipal Code including: 
1. 8 feet of clearance above public sidewalks; 
2. 13 feet of clearance above public local and neighborhood 
streets; 
3. 15 feet of clearance above public collector streets; and 
4. 18 feet of clearance above public arterial streets. 
C. Street trees shall be maintained so as not to become hazard trees as 
defined in Chapter 8.02 of the Tigard Municipal Code. 
END OF SECnON 
Section 2- Street Tree Planting and Maintenance Standards 
Cit y of Tigard Urban Forestry Manual 
City o f T'igard Urban Fores try Code Re,-isions I Volume IV I 13 
Notes: 
Page 2-3 
.
.,. 
Section 3 - Street Tree Removal Standards 
Part 1. Street Tree Removal Standards: 
A. Street trees shall be removed in a manner consistent with tree care 
industry standards. 
B. The city manager or designee shall approve the removal of a street 
tree if any one of the following criteria are met: 
1. The tree is a "hazard tree" as defined in Chapter 8.02 and 
"hazard tree abatement" as defined in Chapter 8.02 cannot be 
completed in a manner that results in tree retention consistent 
with tree care industry standards. 
2. The tree is dead. 
3. The tree is in an advanced state of decline with insufficient live 
foliage, branches, roots or other tissue to sustain life. 
4. The tree is infested with pests or diseases that if left untreated 
will cause the tree to die, enter an advanced state of decline or 
cause other trees to die or enter an advanced state of decline. 
5. The tree has sustained physical damage that will cause the tree 
to die or enter an advanced state of decline. If the physical 
damage was caused by a person in violation of Chapter 8.08 of 
the Tigard Municipal Code, the enforcement process outlined 
in Section 8.02.030 shall be completed prior to approval. 
Notes: 
6. The tree is listed on the nuisance tree list. I See Appendix 6 for 
7. The tree location is such that it would not meet all of the street Nuisance Tree List 
tree planting standards in Section 2, parts 1E and 1F of the 
Urban Forestry Manual if it were a newly planted tree. 
8. The tree roots are causing damage to paved surfaces, 
infrastructure, utilities, buildings or other parts of the built 
environment. 
9. The tree location conflicts with areas of public street widening, 
construction or extension as shown in the Transportation 
System Plan. 
10. Tree removal is required for the purposes of an approved 
building or land use permit, utility or infrastructure installation 
or utility or infrastructure repair. 
11. The tree is recommended for removal by a designated fue 
marshal for Tualatin Valley Fire and Rescue because it presents 
a significant fue risk to habitable structures or limits emergency 
access for rescue workers, and the risk or access issue cannot be 
abated through pruning or other means that results in tree 
retention. 
- -~ - ~- ~ - --
Section 3- Street Tree Removal Standards 
City of Tigard Urban Forestry Manual 
City of Tigard Urban Forestry Code ReYisions I Volume IV I 15 
Page 3-1 
-
N ote:<: 
c. 
D. 
Page 3-2 
12. The tree is part of a stand of trees, and a certified arborist or 
certified forester determines that thinning of interior trees 
within the stand of trees is necessary for overall stand health, 
the thinning will result in no less than 80 percent canopy cover 
at maturity for the area to be thinned, and that thinning of non-
native trees is maximized prior to thinning of native trees. 
Unless removed for thinning purposes (part 1.B.11 above) the city 
manager or designee shall condition the removal of a street tree upon 
the planting of a replacement tree in accordance with the Street Tree 
Planting Standards in Section 2, part 1 of the Urban Forestry Manual. 
The city manager or designee may consider existing trees as 
replacement trees if they meet all applicable species, size, condition and 
location requirements in Section 2, part 1 and were not already required 
to be planted or preserved by the Tigard Municipal Code. 
If the Street Tree Planting Standards in Section 2, part 1 of the Urban 
Forestry Manual preclude replanting within the same right of way 
abutting on, fronting on or adjacent to the property as the tree was 
removed or on private property within 6 feet of the same right of way 
as the tree that was removed, the applicant shall be exempt from 
planting a replacement tree. 
END OF SECTION 
Section 3- Street Tree Removal Standards 
City of Tigard Urban Forest r y Manual 
City of Tigard Urban l ;or~stry Code Rc,· isiom I \'olumc I\ ' I J(, 
Section 4 - Median Tree Planting and Maintenance Standards 
Part 1. 
A. 
B. 
c. 
D. 
Median Tree Planting Standards: 
Median trees shall be planted in a manner consistent with tree care 
industry standards. 
Median trees shall have a minimum caliper of 1 Vz inches at the time 
of planting. 
Median tree species shall be from the street tree list, unless otherwise 
approved by the city manager or designee. 
Median tree species shall be appropriate for the planting environment 
as determined by the city manager or designee and seek to achieve a 
balance of the following: 
1. Consistency with previously approved median tree plans given 
space constraints for roots and branches at maturity; 
2. Compatibility with space constraints for roots and branches at 
maturity; 
3. Providing adequate species diversity citywide and reasonable 
resistance to pests and diseases; and 
4. Consideration of the objectives of the current median tree 
planting proposal. 
E. Median trees shall be provided adequate spacing from new and 
existing trees according to the following standards wherever possible: 
1. Median trees categorized as small stature on the street tree list 
or by the city manager or designee shall be spaced no greater 
than 20 feet on center and not closer than 15 feet on center 
from other newly planted median trees or any existing tree that 
has been in the ground for over three years; 
2. Median trees categorized as medium stature on the street tree 
list or by the city manager or designee shall be spaced no 
greater than 30 feet on center and not closer than 20 feet on 
center from other newly planted median trees or any existing 
tree that has been in the ground for over three years; 
3. Median trees categorized as large stature on the street tree list 
or by the city manager or designee shall be spaced no greater 
than 40 feet on center and not closer than 30 feet on center 
from other newly planted median trees or any existing tree that 
has been in the ground for over three years; and 
4. Any tree determined by the city manager or designee to have a 
mature spread of less than 20 feet shall be considered a small 
stature tree, and spaced accordingly when used as a median 
tree. 
Section 4- Median Tree Planting and Maintenance Standards 
City of Tigard Urban Forestry Manual 
-- - .. .. 
City of Tigard Urban Forestry Code Revisions I Volume l V I 17 
Notes: 
See t\ ppendix 2 for 
Street Tree List 
Page 4-1 
-·---· __ .. 
- --
Note,;: 
See Code Section 
8.08 and Manual 
Section 5 for Median 
Tree Removal 
Standards 
Page 4-2 
F. Median trees shall be placed according to the following standards: 
1. Median trees categorized as small stature on the street tree list 
or by the city manager or designee shall not be planted with the 
center of their trunks closer than 2 feet from any hard surface 
pavmg; 
2. Median trees categorized as medium stature on the street tree 
list or by the city manager or designee shall not be planted with 
the center of their trunks closer than 2 Vz feet from any hard 
surface paving; 
3. Median trees categorized as large stature on the street tree list 
or by the city manager or designee shall not be planted with the 
center of their trunks closer than 3 feet from any hard surface 
pavmg; 
4. Not closer than 4 feet on center from any fire hydrant, utility 
box or utility pole; 
5. Not closer than 2 feet on center from any underground utility; 
6. Not closer than 10 feet on center from a street light standard; 
7. Not closer than 20 feet from a street right of way corner as 
determined by the city manager or designee. The city manager 
or designee may require a greater or lesser corner setback based 
on an analysis of traffic and pedestrian safe ty impacts; 
8. Where there are overhead utility lines, the median tree species 
selected shall be of a type which, at full maturity, will not 
interfere with the lines; and 
9. Any other standards found by the city manager or designee to 
be relevant in order to protect public safety and public or 
private property. 
G . Root barriers shall be installed according to the manufacturer's 
specifications when a street tree is planted within 5 feet of any hard 
surface paving or utility box, or as otherwise required by the city 
H . 
I. 
engmeer. 
Median trees planted prior to the adoption of the most current version 
of the Median Tree Planting Standards shall be exempt from the most 
current version of the Median Tree Planting Standards. However, the 
most current version of the Median Tree Maintenance Standards and 
the most current version of the Median Tree Removal Standards shall 
apply. 
If median tree planting is required by another section of the Urban 
Forestry Manual or Tigard Municipal Code, the city manager or 
designee may allow for an "in lieu of planting fee" equivalent to the 
city's cost to plant a median tree per the standards in Section 4, part 1 
of the Urban Forestry Manual and maintain a street tree per the 
standards in Section 4, part 2 of the Urban Forestry Manual for a 
period of three years after planting. Payment of an in lieu of planting 
fee shall satisfy the median tree planting requirement. 
Section 4- Median Tre e Planting and Maintenance Standard s 
Cit y of Tigard Urban Forestry Manual 
City o f Tigard Urban J."ore,Lry Cod~ RcYisions I \'olumc /\ ' I I H 
Part 2. Median Tree Maintenance Standards: 
A. Median trees shall be maintained in a manner consistent with tree care 
industry standards. 
B. Median trees shall be maintained in a manner that does not impede 
public street or sidewalk traffic consistent with the specifications in 
section 7.40.060A of the Tigard Municipal Code including: 
1. 8 feet of clearance above public sidewalks; 
2. 13 feet of clearance above public local and neighborhood 
streets; 
3. 15 feet of clearance above public collector streets; and 
4. 18 feet of clearance above public arterial streets. 
C. Median trees shall be maintained so as not to become hazard trees as 
defined in Chapter 8.02 of the Tigard Municipal Code. 
END Of SECTION 
Section 4- Median Tree Planting and Maintenance Standards 
City of Tigard Urban Forestr y Manual 
City of Tigard Urban Forestry Code Re,·isions I Volume IV I 19 
Notes: 
Page 4-3 

Section 5 - Median Tree Removal Standards 
Part 1. Median Tree Removal Standards : 
A. Median trees shall be removed in a manner consistent with tree care 
industry standards. 
B. The city manager or designee shall approve the removal of a median 
tree if any one of the following criteria are met: 
1. The tree is a "hazard tree" as defined in Chapter 8.02 and 
"hazard tree abatement" as defined in Chapter 8.02 cannot be 
completed in a manner that results in tree retention consistent 
with tree care industry standards. 
2. The tree is dead. 
3. The tree is in an advanced state of decline with insufficient live 
foliage, branches, roots or other tissue to sustain life. 
4. The tree is infested with pests or diseases that if left untreated 
will cause the tree to die, enter an advanced state of decline or 
cause other trees to die or enter an advanced state of decline. 
5. The tree has sustained physical damage that will cause the tree 
to die or enter an advanced state of decline. If the physical 
damage was caused by a person in violation of Chapter 8.08 of 
the Tigard Municipal Code, the enforcement process outlined 
in Section 8.02.030 shall be completed prior to approval. 
Notes: 
6. The tree is listed on the nuisance tree list. I See Appendix 6 for 
7. The tree location is such that it would not meet all of the Nuisance Tree List 
median tree planting standards in Section 4, parts 1E and 1F of 
the Urban Forestry Manual if it were a newly planted tree. 
8. The tree roots are causing damage to paved surfaces, 
infrastructure, utilities, buildings or other parts of the built 
environment. 
9. The tree location conflicts with areas of public street widening, 
construction or extension as shown in the Transportation 
System Plan. 
10. Tree removal is required for the purposes of an approved 
building or land use permit, utility or infrastructure installation 
or utility or infrastructure repair. 
11. The tree is recommended for removal by a designated fire 
marshal for Tualatin Valley Fire and Rescue because it presents 
a significant fue risk to habitable structures or limits emergency 
access for rescue workers, and the risk or access issue cannot be 
abated through pruning or other means that results in tree 
-
retention. 
Section 5- Medi a n Tree Remo va l Standards 
Cit y of Tigard Urban Forestry Manual 
City of Tigard Urban Forestry Code Rc"isions I \' olumc I\' I 21 
Page 5-1 
-
N ote,;: 
Page 5-2 
12. The tree is part of a stand of trees, and a certified arborist or 
certified forester determines that thinning of interior trees 
within the stand of trees is necessary for overall stand health, 
the thinning will result in no less than 80 percent canopy 
cover at maturity for the area to be thinned, and that thinning 
of non-native trees is maximized prior to thinning of native 
trees. 
C. Unless removed for thinning purposes (part 1.B.11 above) the city 
manager or designee shall condition the removal of a median tree 
upon the planting of a replacement tree within the same median as 
the tree was removed in accordance with the Median Tree Planting 
Standards in Section 4, part 1 of the Urban Forestry Manual. The city 
manager or designee may consider existing trees as replacement trees 
if they meet all applicable species, size, condition and location 
requirements in Section 4, part 1 and were not already required to be 
planted or preserved by the Tigard Municipal Code. 
D . If the Median Tree Planting Standards in Section 4, part 1 of the 
Urban Forestry Manual preclude replanting within the same median 
as the tree was removed, the applicant shall be exempt from planting 
a replacement tree. 
END Of SECTION 
Section 5- Median Tree Removal Standards 
Cit y of Tigard Urban Forestr y Manual 
CitY of Tigard Urban J:orcstn· Code Re,·isions I \'olumc I\ ' I 22 
Section 6 - Sensitive Lands Tree Removal and Replacement Standards 
Part 1. Sensitive Lands Tree Removal Standards: I Notes: 
A. Native trees in sensitive lands shall be removed in a manner consistent 
with tree care industry standards. 
B. The city manager or designee shall approve the removal of a native 
tree in sensitive lands if any one of the following criteria are met: 
1. The tree is a "hazard tree" as defined in Chapter 8.02 and 
"hazard tree abatement" as defined in Chapter 8.02 cannot be 
completed in a manner that results in tree retention consistent 
with tree care industry standards. 
2. The tree is dead. 
3. The tree is in an advanced state of decline with insufficient live 
foliage, branches, roots or other tissue to sustain life. 
4. The tree is infested with pests or diseases that if left untreated 
will cause the tree to die, enter an advanced state of decline, or 
cause other trees to die or enter an advanced state of decline. 
5. The tree has sustained physical damage that will cause the tree 
to die or enter an advanced state of decline. If the physical 
damage was caused by a person in violation of Chapter 8.10 of 
the Tigard Municipal Code, the enforcement process outlined 
in Section 8.02.030 shall be completed prior to approval. 
6. The tree roots are causing damage to paved surfaces, 
infrastructure, utilities, buildings or other parts of the built 
environment. 
7. The tree location conflicts with areas of public street widening, 
construction or extension as shown in the Transportation 
System Plan. 
8. Tree removal is required for the purposes of an approved 
building or land use permit, utility or infrastructure installation 
or utility or infrastructure repair. 
9. The tree is recommended for removal by a designated fire 
marshal for Tualatin Valley Fire and Rescue because it presents 
a significant fue risk to habitable structures or limits emergency 
access for rescue workers, and the risk or access issue cannot be 
abated through pruning or other means that results in tree 
retention. 
10. A certified arborist or certified forester determines that 
thinning of interior trees within a stand of trees is necessary for 
overall stand health, the thinning will result in no less than 80 
percent canopy cover at maturity for the area to be thinned, 
and that thinning of non-native trees is maximized prior to 
thinning of native trees. 
Section 6- Sensitive Lands Tree Removal and 
Replacement Standards 
City of Tigard Urban Forestry Manual 
City of Tigard Urban Forestry Code Re,·isions I Volume IV I 23 
Page 6-1 
Notes: 
Sec r\ ppendix 5 fo r 
N a tive Tree List 
Page 6-2 
c. 
D. 
Unless removed for thinning purposes (part 1.B.1 0 above) the city 
manager or designee shall condition the removal of each tree in 
sensitive lands upon the planting of a replacement tree in accordance 
with the Sensitive Lands Tree Replacement Standards in Section 6, 
part 2 of the Urban Forestry Manual. 
If the Sensitive Lands Tree Replacement Standards in Section 6, part 2 
preclude replanting within the same property as the tree that was 
removed, the applicant shall be exempt from planting a replacement 
tree. 
Part 2. Sensitive Lands Tree Replacement Standards: 
A. 
B. 
c. 
D. 
E. 
Replacement trees shall be planted in a manner consistent with tree 
care industry standards. 
The minimum size of a replacement tree shall be 2 feet in height (from 
the top of the root ball) or equivalent to a 1 gallon container size. 
Replacement trees shall be selected from the native tree list in the 
Urban Forestry Manual. 
The city manager or designee may consider native trees that are less 
than 6 inches DBH as replacement trees if they meet all applicable 
species, size, condition and location requirements in this section and 
were not already required to be planted by the Tigard Municipal Code. 
The location of replacement trees shall be as follows : 
1. As close as practicable to the location of the tree that was 
removed provided the location complies with the other 
standards in this section; 
2. No closer than 10 feet on center from newly planted or 
existing trees; 
3. Trees categorized as small stature on the native tree list in the 
Urban Forestry Manual or by the city manager or designee 
shall be spaced no closer than 15 feet from the face of 
habitable buildings; 
4. Trees categorized as medium stature on the native tree list in 
the Urban Forestry Manual or by the city manager or 
designee shall be spaced no closer than 20 feet from the face 
of habitable buildings; 
5. Trees categorized as large stature on the native tree list in the 
Urban Forestry Manual or by the city manager or designee 
shall be spaced no closer than 30 feet from the face of 
habitable buildings; 
6. Trees categorized as small stature on the native tree list in the 
Urban Forestry Manual or by the city manager or designee 
shall not be planted with the center of their trunks closer than 
2 feet from any hard surface paving; 
Section 6- Sensitive Land s Tree R e moval and 
Replacement Standards 
Cit y of Tigard Urban F o r es try Manual 
Cit;· ofTi~-,>ard Urban l 'o r~stry Code Re,·isions I \'olumc I\ ' I 24 
F. 
7. 
8. 
Trees categorized as medium stature on the native tree list in 
the Urban Forestry Manual shall not be planted with the center 
of their trunks closer than 2 Vz feet from any hard surface 
paving; Trees categorized as large stature on the native tree list 
in the Urban Forestry Manual or by the city manager or 
designee shall not be planted with the center of their trunks 
closer than 3 feet from any hard surface paving; and 
Where there are overhead utility lines, the tree species selected 
shall be of a type which, at full maturity, will not interfere with 
the lines. 
The city manager or designee may allow for an "in lieu of planting fee" 
equivalent to the city's cost to plant a tree in sensitive lands per the 
standards in this Section and maintain a tree in sensitive lands per the 
standards in Section 8.10.030 of the Tigard Municipal Code for a 
period of three years after planting. Payment of an in lieu of planting 
fee shall satisfy the sensitive lands tree replacement requirement. 
END OF SECTION 
Section 6- Sen s itive Lands Tree Removal and 
Replacement Standards 
Cit y of Tigard Urban For es tr y Manual 
City of Tigard Urban Forestry Code Re,·isions I Volume IV I 25 
Notes: 
See Master Fees and 
Charges Schedule for 
current fees 
Page 6-3 

Part 1. 
A . 
B. 
Section 7 - Development Tree Removal and Replacement Standards 
Development Tree Removal Standards: 
Trees subject to the requirements of Chapter 8.12 shall be removed in 
a manner consistent with tree care industry standards. 
The city manager or designee shall approve the removal of trees 
subject to the requirements of Chapter 8.12 if any one of the 
following criteria are met: 
1. The tree is a "hazard tree" as defined in Chapter 8.02 and 
"hazard tree abatement" as defined in Chapter 8.02 cannot be 
completed in a manner that results in tree retention consistent 
with tree care industry standards. 
2. The tree is dead. 
3. The tree is in an advanced state of decline with insufficient live 
foliage, branches, roots or other tissue to sustain life. 
4. The tree is infested with pests or diseases that if left untreated 
will cause the tree to die, enter an advanced state of decline or 
cause other trees to die or enter an advanced state of decline. 
5. 
6. 
7. 
The tree has sustained physical damage that will cause the tree 
to die or enter an advanced state of decline. If the physical 
damage was caused by a person in violation of Chapter 8.12 of 
the Tigard Municipal Code, the enforcement process outlined 
in Section 8.02.030 shall be completed prior to approvaL 
The tree is listed in the nuisance tree list. 
The tree roots are causing damage to paved surfaces, 
infrastructure, utilities, buildings or other parts of the built 
environment. 
8. The tree location conflicts with areas of public street widening, 
construction or extension as shown in the Transportation 
System Plan. 
9. Tree removal is required for the purposes of an approved 
building or land use permit, utility or infrastructure installation, 
or utility or infrastructure repair. 
10. The tree is recommended for removal by a designated fire 
marshal for Tualatin Valley Fire and Rescue because it presents 
a significant fue risk to habitable structures or limits emergency 
access for rescue workers, and the risk or access issue cannot be 
abated through pruning or other means that results in tree 
retention. 
11 . The tree is part of a stand of trees, and a certified arborist or 
certified forester determines that thinning of interior trees 
within the stand of trees is necessary for overall stand health, 
the thinning will result in no less than 80 percent canopy cover 
at maturity for the area to be thinned, and that thinning of non-
native trees is maximized prior to thinning of native trees. 
Section 7- Development Tree Removal and 
Replacement Standards 
Cit y of Tigard Urban Forestr y Manual 
City of Tigard Urban Forestry Code ReYisions I Volume IV I 27 
Note~: 
See Appendix 6 for 
Nuisance Tree List 
Page 7-1 
Note,;: 
See Appendices 2-5 
for Approved Tree 
Lists 
See Appendix 5 for 
Native Tree List 
Page 7-2 
c. Unless removed for thinning purposes (Part 1.B.11 above) the city 
manager or designee shall condition the removal of each tree upon the 
planting of a replacement tree in accordance with the Development 
Tree Replacement Standards in Section 7, part 2 of the Urban Forestry 
Manual. 
D. If the Development Tree Replacement Standards in Section 7, part 2 
preclude replanting within the same property as the tree that was 
removed, the applicant shall be exempt from planting a replacement 
Part 2. 
A. 
B. 
c. 
D . 
tree. 
Development Tree Replacement Standards: 
Replacement trees shall be planted in a manner consistent with tree 
care industry standards. 
The replacement tree shall be located so as to replace the function of 
the tree that was removed. For example, trees removed from parking 
lots shall be replaced in parking lots and trees removed from 
landscape buffers shall be replaced in landscape buffers. If planting in 
the same location would not comply with the other standards in this 
section, the replacement tree shall be planted as close as practicable to 
the tree that was removed in compliance with the other standards in 
this section. 
The replacement species shall be the same stature or greater (at 
maturity) as the tree that was removed. If planting the same stature or 
greater tree would not comply with the other standards in this section, 
the replacement tree shall be the most similar stature practicable as the 
tree that was removed in compliance with the other standards in this 
section. 
If the tree that was removed was part of a stand of trees, then the 
following standards apply to the replacement tree: 
1. The replacement tree shall be selected from the native tree list 
in the Urban Forestry Manual unless otherwise approved by the 
city manager or designee; 
2. The minimum size of the replacement tree shall be 2 feet in 
height (from the top of the root ball) or equivalent to a 1 gallon 
container size; and 
3. The replacement tree shall be located as follows : 
a. No closer than 10 feet on center from newly planted or 
existing trees; 
b . Trees categorized as small stature on the native tree list 
in the Urban Forestry Manual or by the city manager or 
designee shall be spaced no closer than 15 feet from the 
face of habitable buildings; 
c. Trees categorized as medium stature on the native tree 
list in the Urban Forestry Manual or by the city 
manager or designee shall be spaced no closer than 20 
feet from the face of habitable buildings; 
Section 7- Development Tree Remo va l and 
Replacement Standards 
City of Tigard U rban Forestr y Manual 
City of Tigard Urban l'orcstrY Code Rc,-isions I \ 'olumc 1\ ' I 28 
E. 
II 
-- . -
d . Trees categorized as large stature on the native tree 
list in the Urban Forestry Manual or by the city 
manager or designee shall be spaced no closer than 
30 feet from the face of habitable buildings; 
e. Trees categorized as small stature on the native tree 
list in the Urban Forestry Manual or by the city 
manager or designee shall not be planted with the 
center of their trunks closer than 2 feet from any 
hard surface paving; 
f. Trees categorized as medium stature on the native 
tree list in the Urban Forestry Manual shall not be 
planted with the center of their trunks closer than 2 
Vz feet from any hard surface paving; 
g. Trees categorized as large stature on the native tree 
list in the Urban Forestry Manual or by the city 
manager or designee shall not be planted with the 
center of their trunks closer than 3 feet from any 
hard surface paving; and 
h. Where there are overhead utility lines, the tree 
species selected shall be of a type which, at full 
maturity, will not interfere with the lines. 
If the tree that was removed was an open grown tree, then the 
follo~ving standards apply to the replacement tree: 
1. The replacement tree shall be selected from any of the tree lists 
in the Urban Forestry Manual (except the nuisance tree list) 
unless otherwise approved by the city manager or designee; 
2. The minimum size of the replacement tree shall be 1 Vz inch 
caliper for deciduous or 6 feet in height for evergreen; and 
3. The replacement tree shall be located as follows: 
a. Trees categorized as small stature on any of the tree lists 
in the Urban Forestry Manual or by the city manager or 
designee shall be spaced no closer than 15 feet on 
center from other newly planted or existing trees and 10 
feet from the face of habitable buildings; 
b. Trees categorized as medium stature on any of the tree 
lists in the Urban Forestry Manual or by the city 
manager or designee shall be spaced no closer than 20 
feet on center from other newly planted or existing 
trees and 15 feet from the face of habitable buildings; 
c. Trees categorized as large stature on any of the tree lists 
in the Urban Forestry Manual or by the city manager or 
designee shall be spaced no closer than 30 feet on 
center from other newly planted or existing trees and 20 
feet from the face of habitable buildings; 
Section 7- Development Tree Removal and 
Replacement Standards 
City of Tigard Urban Forestry Manual 
City ofTigard Urban Fores try Code Revisions I Volume IV I 29 
Notes: 
See Appendices 2-5 
for Approved Tree 
Lists 
See Appendix 6 for 
Nuisance Tree List 
Page 7-3 
Note~: 
Sec l\h~ter Fees and 
Charges Schedule for 
current fees 
Page 7-4 
F. 
G. 
d. 
e. 
f. 
g. 
h. 
Trees determined by the city manager or designee to 
have a mature spread of less than 20 feet shall be 
considered small stature, and shall be spaced no closer 
than 15 feet on center from other newly planted or 
existing trees and 10 feet from the face of habitable 
buildings; 
Trees categorized as small stature on any of the tree 
lists in the Urban Forestry Manual or by the city 
manager or designee shall not be planted with the 
center of their trunks closer than 2 feet from any hard 
surface paving; 
Trees categorized as medium stature on any of the 
tree lists in the Urban Forestry Manual shall not be 
planted with the center of their trunks closer than 2 
V2 feet from any hard surface paving; 
Trees categorized as large stature on any of the tree 
lists in the Urban Forestry Manual or by the city 
manager or designee shall not be planted with the 
center of their trunks closer than 3 feet from any hard 
surface paving; and 
Where there are overhead utility lines, the tree species 
selected shall be of a type which, at full maturity, will 
not interfere with the lines. 
The city manager or designee may consider existing trees as 
replacement trees if they meet all applicable species, size, condition 
and location requirements in this Section and were not already 
required to be planted or preserved by the Tigard Municipal Code. 
The city manager or designee may allow for an "in lieu of planting 
fee" equivalent to the city's cost to plant a tree per the standards in 
this Section and maintain a tree per the standards in section 8.12.030 
of the Tigard Municipal Code for a period of three years after 
planting. Payment of an in lieu of planting fee shall satisfy the 
development tree replacement requirement. 
END OF SECTION 
Section 7- De ve lopment Tree Removal and 
Replacement Standards 
City of Tigard Urban Forestry Manual 
City or Tigard Urban , .. or~stry Code Re,·isions I \'olume 1\ ' I 30 
Section 8- Urban Forestry Fund Tree Removal and Replacement Standards 
Part 1. Urban Forestry Fund Tree RemovalStandards : 
A. Trees subject to the requirements of Chapter 8.14 shall be removed in a 
manner consistent with tree care industry standards. 
B. The city manager or designee shall approve the removal of trees subject 
to the requirements of Chapter 8.14 if any one of the following criteria 
are met: 
1. The tree is a "hazard tree" as defined in Chapter 8.02 and 
"hazard tree abatement" as defmed in Chapter 8.02 cannot be 
completed in a manner that results in tree retention consistent 
with tree care industry standards. 
2. The tree is dead. 
3. The tree is in an advanced state of decline with insufficient live 
foliage, branches, roots or other tissue to sustain life. 
4. The tree is infested with pests or diseases that if left untreated 
will cause the tree to die, enter an advanced state of decline or 
cause other trees to die or enter an advanced state of decline. 
5. The tree has sustained physical damage that will cause the tree 
to die or enter an advanced state of decline. If the physical 
damage was caused by a person in violation of Chapter 8.14 of 
the Tigard Municipal Code, the enforcement process outlined 
in Section 8.02.030 shall be completed prior to approval. 
Notes: 
6. The tree is listed in the nuisance tree list. I See Appendix 6 for 
7. The tree roots are causing damage to paved surfaces, Nuisance Tree Ligt 
infrastructure, utilities, buildings or other parts of the built 
environment. 
8. The tree location conflicts with areas of public street widening, 
construction or extension as shown in the Transportation 
System Plan. 
9. Tree removal is required for the purposes of an approved 
building or land use permit, utility or infrastructure installation 
or utility or infrastructure repair. 
10. The tree is recommended for removal by a designated fue 
marshal for Tualatin Valley Fire and Rescue because it presents 
a significant fue risk to habitable structures or limits emergency 
access for rescue workers, and the risk or access issue cannot be 
abated through pruning or other means that results in tree 
retention. 
11. The tree is part of a stand of trees, and a certified arborist or 
certified forester determines that thinning of interior trees 
within the stand of trees is necessary for overall stand health, 
the thinning will result in no less than 80 percent canopy cover 
at maturity for the area to be thinned, and that thinning of non-
native trees is maximized prior to thinning of native trees. 
Section 8- Urban Forestry Fund Tree Removal and 
Replacement Standards 
City of Tigard Urban Forestry Manual 
City of Tigard Urban Forestry Code Re,·isions I Volume IV I 31 
Page 8-1 
- - --
N otes: 
Sec Appendices 2-5 
for Approved Tree 
I .ists 
Sec Appendix 5 for 
the Native Tree List 
Page 8-2 
c. 
D. 
Part 2. 
A. 
B. 
c. 
Unless removed for thinning purposes (part 1.B.11 above) the city 
manager or designee shall condition the removal of each tree upon the 
planting of a replacement tree in accordance with the Urban Forestry 
Fund Tree Replacement Standards in Section 8, part 2 of the Urban 
Forestry Manual. 
If the Urban Forestry Fund Tree Replacement Standards in Section 8, 
part 2 preclude replanting within the same property as the tree that 
was removed, the applicant shall be exempt from planting a 
replacement tree. 
Urban Forestry Fund Tree Replacement Standards: 
Replacement trees shall be planted in a manner consistent with tree 
care industry standards. 
The replacement species shall be the same stature or greater (at 
maturity) as the tree that was removed. If planting the same stature or 
greater tree would not comply with the other standards in this section, 
the replacement tree shall be the most similar stature practicable as the 
tree that was removed in compliance with the other standards in this 
section. 
If the tree that was removed was part of a stand of trees, then the 
following standards apply to the replacement tree: 
1. The replacement tree shall be selected from the native tree list 
in the Urban Forestry Manual unless otherwise approved by the 
city manager or designee; 
2. The minimum size of the replacement tree shall be 2 feet in 
height (from the top of the root ball) or equivalent to a 1 gallon 
container size; and 
3. The replacement tree shall be located as follows : 
a. No closer than 10 feet on center from newly planted or 
existing trees; 
b. Trees categorized as small stature on the native tree list 
in the Urban Forestry Manual or by the city manager or 
designee shall be spaced no closer than 15 feet from the 
face of habitable buildings; 
c. Trees categorized as medium stature on the native tree 
list in the Urban Forestry Manual or by the city 
manager or designee shall be spaced no closer than 20 
feet from the face of habitable buildings; 
d. Trees categorized as large stature on the native tree list 
in the Urban Forestry Manual or by the city manager or 
designee shall be spaced no closer than 30 feet from the 
face of habitable buildings; 
e. Trees categorized as small stature on the native tree list 
in the Urban Forestry Manual or by the city manager or 
designee shall not be planted with the center of their 
trunks closer than 2 feet from any hard surface paving; 
Section 8 - Urban Forestry Fund Tree Remo va l and 
Replacement Standards 
Cit y of Tigard Urban Forestr y Manual 
City o f Tigard Urban l'orcstry Code Rc,·isions I \'olumc 1\' I 32 
D. 
II 
f. 
g. 
Trees categorized as medium stature on the native tree 
list in the Urban Forestry Manual shall not be planted 
with the center of their trunks closer than 2 Vz feet 
from any hard surface paving; 
Trees categorized as large stature on the native tree list 
in the Urban Forestry Manual or by the city manager or 
designee shall not be planted with the center of their 
trunks closer than 3 feet from any hard surface paving; 
and 
h. Where there are overhead utility lines, the tree species 
selected shall be of a type which, at full maturity, will 
not interfere with the lines. 
If the tree that was removed was an open grown tree, then the 
following standards apply to the replacement tree: 
1. The replacement tree shall be selected from any of the tree lists 
in the Urban Forestry Manual (except the nuisance tree list) 
unless otherwise approved by the city manager or designee; 
2. The minimum size of the replacement tree shall be 1 Vz inch 
caliper for deciduous or 6 feet in height for evergreen; and 
3. The replacement tree shall be located as follows: 
a. Trees categorized as small stature on any of the tree lists 
in the Urban Forestry Manual or by the city manager or 
designee shall be spaced no closer than 15 feet on 
center from other newly planted or existing trees and 10 
feet from the face of habitable buildings; 
b. Trees categorized as medium stature on any of the tree 
lists in the Urban Forestry Manual or by the city 
manager or designee shall be spaced no closer than 20 
feet on center from other newly planted or existing 
trees and 15 feet from the face of habitable buildings; 
c. Trees categorized as large stature on any of the tree lists 
in the Urban Forestry Manual or by the city manager or 
designee shall be spaced no closer than 30 feet on 
center from other newly planted or existing trees and 20 
feet from the face of habitable buildings; 
d. Trees determined by the city manager or designee to 
have a mature spread of less than 20 feet shall be 
considered small stature, and shall be spaced no closer 
than 15 feet on center from other newly planted or 
existing trees and 10 feet from the face of habitable 
buildings; 
e. Trees categorized as small stature on any of the tree lists 
in the Urban Forestry Manual or by the city manager or 
designee shall not be planted with the center of their 
trunks closer than 2 feet from any hard surface paving; 
Se c tion 8- Urban Forestry Fund Tree Remo va l and 
Replacement Standards 
City of Ti ga rd Urban Forestr y Manual 
City of Tigard Urban Forestry Code Revisions I Volume IV I 33 
Notes: 
See Appendices 2-5 
for Approved Tree 
Lists 
See Appendix 6 for 
N uisance Tree List 
Page 8-3 
Notes: 
Sec Master Fees and 
Charges Schedule 
for current fee 
Page 8-4 
E. 
F. 
f. 
g. 
h. 
Trees categorized as medium stature on any of the 
tree lists in the Urban Forestry Manual shall not be 
planted with the center of their trunks closer than 2 
Vz feet from any hard surface paving; 
Trees categorized as large stature on any of the tree 
lists in the Urban Forestry Manual or by the city 
manager or designee shall not be planted with the 
center of their trunks closer than 3 feet from any hard 
surface paving; and 
Where there are overhead utility lines, the tree species 
selected shall be of a type which, at full maturity, will 
no t interfere with the lines. 
The city manager or designee may consider existing trees as 
replacement trees if they meet all applicable species, size, condition 
and location requirements in this section and were not already 
required to be planted or preserved by the Tigard Municipal Code. 
The city manager or designee may allow for an "in lieu of planting 
fee" equivalent to the city's cost to plant a tree per the standards in 
this section and maintain a tree per the standards in section 8.14.030 
of the Tigard Municipal Code for a period of three years after 
planting. Payment of an in lieu of planting fee shall satisfy the urban 
forestry fund tree replacement requirement . 
• END OF SECTION 
Section 8 - Urban Forestr y Fund Tree Removal and 
Replacement Standards 
City of Tigard Urban Forestry Manual 
Ci tr o f Tigard Urban l 'or~' trr Code R ~,- i , i om I \'olumc I\ ' I 34 
Section 9 - Heritage Tree Designation Removal Standards 
Part 1. 
A. 
B. 
Heritage Tree Designation Removal Standards: 
Heritage trees subject to the requirements of Chapter 8.16 shall be 
removed in a manner consistent with tree care industry standards. 
The city manager or designee shall approve the removal of heritage 
tree designation if any one of the following criteria are met for a 
designated heritage tree: 
1. The heritage tree is a "hazard tree" as defined in Chapter 8.02 
and "hazard tree abatement" as defined in Chapter 8.02 cannot 
be completed in a manner that results in tree retention 
consistent with tree care industry standards. 
2. The heritage tree is dead. 
3. The heritage tree is in an advanced state of decline with 
insufficient live foliage, branches, roots or other tissue to 
sustain life. 
4. The heritage tree has sustained physical damage that will cause 
the tree to die or enter an advanced state of decline. If the 
physical damage was caused by a person in violation of Chapter 
8.16 of the Tigard Municipal Code, the enforcement process 
outlined in Section 8.02.030 shall be completed prior to 
approval. 
5. The tree is recommended for removal by a designated fue 
marshal for Tualatin Valley Fire and Rescue because it presents 
a significant fue risk to habitable structures or limits emergency 
access for rescue workers, and the risk or access issue cannot be 
abated through pruning or other means that results in tree 
retention. 
6. The heritage tree is part of a stand of heritage trees, and a 
certified arborist or certified forester determines that thinning 
of interior heritage trees within the stand of heritage trees is 
necessary for overall stand health, the thinning will result in no 
less than 80 percent canopy cover at maturity for the area to be 
thinned, and that thinning of non-native heritage trees is 
maximized prior to thinning of native heritage trees. 
C. Replacement of heritage trees is not required unless a heritage tree is 
also subject to other provisions of the Tigard Municipal Code that 
require replacement. 
END OF SECTION 
Section 9- H eritage Tree Designation Removal Standards 
City of Tigard Urban Forestr y Manual 
City of Tigard Urban Forestry Code Re,·isions I Volume IV I 35 
Notes: 
Page 9-1 

Section 10- Urban Forestry Plan Standards 
Part 1. Urban Forestry Plan- Tree Preservation and Removal Site Plan 
Requirements: 
A. The plan shall be standard sizeD (24" x 36"), a reduced legal size and 
a PDF, and include all items in part LB-O below. When required for 
clarity, the development impact area information in part 1.1 may be 
detailed separately on multiple plan sheets provided that all of the 
remaining items in part 1 are included for reference. 
B. Date of drawing or last revision. 
C. North arrow. 
D . Bar scale as follows: 
1. Less than 1.0 acres: 
2. 1.0 - 5.0 acres: 
3. 5.0- 20.0 acres: 
4. Over 20.0 acres: 
1" = 10' 
1" = 20' 
1" =50' 
1" = 100'. 
E. Site address or assessor's parcel number. 
F. The location of existing and proposed property lines. 
G. Location of existing and proposed topographic lines at 1-foot 
contours unless otherwise approved. 
H. The location and type of sensitive lands areas. 
I. Proposed activities within the development impact area, including but 
not limited to: 
1. Construction of structures and walls; 
2. Paving and graveling; 
3. Utility and irrigation installation; 
4. Construction parking and construction equipment storage; 
5. Landscaping; 
6. Grading and filling; 
7. Stockpiling; 
8. Demolition and tree removal; 
9. Trenching and boring; and 
10. Any other activities that require excavation or soil disturbance. 
J. The trunk locations, drip lines, assigned numbers and "X" marks when 
applicable (indicating trees proposed for removal) for the following 
trees within the development impact area and within 25 feet of the 
development impact area: 
1. Trees greater than or equal to 6 inch DBH; and 
2. Other trees that require a permit to remove by Title 8 and are 
less than 6 inch DBH. 
K. The trunk locations, driplines and assigned numbers for the following 
trees that are not within the development impact area: 
1. Open grown trees greater than or equal to 6 inch DBH; and 
- - -· -- --- --
Section 10 - Urban Forestry Plan Standards 
City of Tigard Urban Forestry Manual 
City of Tigard Urban Forestry Code Re,·isions I Volume IV I 37 
Notes: 
See Appendix 7 for 
Example Tree 
Preservation and 
Removal Site Plan 
Page 10-1 
-
N otes: 
Sec Appendix 8 for 
Example Tree 
Canopy Site Plan 
Page 10-2 
2. Other trees that require a permit to remove by Title 8 and are 
less than 6 inch DBH. 
L. The driplines of stand grown trees greater than or equal to 6 inch 
DBH that form a contiguous tree canopy. The driplines may be 
delineated at the outer edge of the stand. Each stand shall be assigned 
a number. 
M. The location and type of proposed tree protection fencing. If the 
location of the tree protection fencing will be phased, indicate the 
location of the tree protection fencing for each corresponding phase. 
Tree protection fencing shall be minimum 5-foot tall metal unless 
otherwise approved by the city manager or designee. 
N . Any supplemental tree preservation specifications consistent with tree 
care industry standards that the project arborist or landscape architect 
has determined are necessary for the continued viability of trees 
identified for preservation. 
0. A signature of approval and statement &om the project arborist or 
landscape architect, attesting that the tree preservation and removal 
site plan meets all of the requirements in Section 1 0, part 1 of the 
Urban Forestry Manual. 
Part 2. 
A . 
B. 
c. 
D . 
Urban Forestry Plan- Tree Canopy Site Plan Requirements: 
The plan shall be standard sizeD (24" x 36"), a reduced legal size and 
PDF format, and include all items in part 2.B-O below. 
Date of drawing or last revision. 
North arrow. 
Bar scale as follows : 
1. less than 1.0 acres: 
2. 1.0 - 5.0 acres: 
3. 5.0- 20.0 acres: 
4. Over 20.0 acres: 
1" = 10' 
1" = 20' 
1" =50' 
1" = 100'. 
E. Site address or assessor's parcel number. 
F. The location of proposed property lines. 
G . The location of proposed building footprints, utilities and irrigation, 
streets and other paved areas. 
H . The trunk locations, driplines and assigned numbers for trees to be 
preserved in parts 1.] and 1.K. Each tree on both the tree 
preservation and removal site plan and tree canopy site plan shall be 
assigned the same number on both plans. 
I. The dripline locations of stand grown trees proposed for preservation 
greater than or equal to 6 inch DBH that form a contiguous tree 
canopy. The dripline may be delineated at the outer edge of the stand. 
Each stand shall be assigned a number. Each stand on both the tree 
preservation and removal site plan and tree canopy site plan shall be 
assigned the same number on both plans. 
] . The location of existing or potential areas of tree growth limiting soils 
due to compaction, drainage, fertility, pH, contamination or other 
factors . 
Section 10- Urban Fore s try Plan Standa rd s 
Cit y of Tigard Urban Forestry Manual 
CitY of 'l'igaru Urban l'orcstn· Code RcYisions I \'olumc I\ ' I .1H 
K. 
L. 
I • 
-
Methods for improving areas of tree growth limiting soils if tree 
planting is proposed in those locations. 
The location, species, caliper (in inches for deciduous) or height (in feet 
for evergreen), assigned numbers and depiction of the mature tree 
canopy (in feet as identified on any of the tree lists in the Urban 
Forestry Manual or by the city manager or designee) for all trees to be 
planted and maintained as open grown trees. The minimum size for all 
trees planted and maintained as open grown trees is 1 Vz inch caliper 
for deciduous or 6 feet in height for evergreen. Open grown trees shall 
be selected from any of the tree lists in the Urban Forestry Manual 
(except the nuisance tree list) unless otherwise approved by the city 
manager or designee. If an open grown tree approved for planting is 
not identified on any of the tree lists in the Urban Forestry Manual, 
then the project arborist or landscape architect shall determine the 
average mature tree canopy spread using available scientific literature 
for review and approval by the city manager or designee. The city 
manager or designee may consider trees less than 6 inch DBH as 
equivalent to newly planted trees if they meet all applicable species, 
size, condition and location requirements in this section. Overall, the 
selection of open grown trees shall result in a reasonable amount of 
diversity for the site. Open grown trees shall be located as follows: 
1. Trees categorized as small stature on any of the tree lists in the 
Urban Forestry Manual or by the city manager or designee shall 
be spaced no closer than 15 feet on center from other newly 
planted or existing trees and 10 feet from the face of habitable 
buildings. In downtown Tigard (Mixed Use-Central Business 
District, MU-CBD), the setback from the face of habitable 
buildings may be reduced if approved by the city manager or 
designee; 
2. Trees categorized as medium stature on any of the tree lists in 
the Urban Forestry Manual or by the city manager or designee 
shall be spaced no closer than 20 feet on center from other 
newly planted or existing trees and 15 feet from the face of 
habitable buildings. In downtown Tigard (Mixed Use-Central 
Business District, MU-CBD), the setback from the face of 
habitable buildings may be reduced if approved by the city 
manager or designee ; 
3. Trees categorized as large stature on any of the tree lists in the 
Urban Forestry Manual or by the city manager or designee shall 
be spaced no closer than 30 feet on center from other newly 
planted or existing trees and 20 feet from the face of habitable 
buildings. In downtown Tigard (Mixed Use-Central Business 
District, MU-CBD), the setback from the face of habitable 
buildings may be reduced if approved by the city manager or 
designee; 
Section 10- Urban Forestr y Plan Standards 
Cit y of Tigard Urban Forestry Manual 
-- - - --
City of T igard Urban Forestry Code Rc,-isions I Volume IV I 39 
Notes: 
Sec Appendices 2-5 
for Approved Tree 
Lists 
See Appendix 6 for 
Nuisance Tree List 
Page 10-3 
- --- - - --
N otes: 
Sec Appendix 5 
for Native Tree 
List 
Page 10-4 
M . 
4. 
5. 
6. 
7. 
8. 
Trees determined by the city manager or designee to have a 
mature spread of less than 20 feet shall be considered small 
stature, and shall be spaced no closer than 15 feet on center 
from other newly planted or existing trees and 10 feet from 
the face of habitable buildings. In downtown Tigard (Mixed 
Use-Central Business District, MU-CBD), the setback from 
the face of habitable buildings may be reduced if approved by 
the city manager or designee; 
Trees categorized as small stature on any of the tree lists in 
the Urban Forestry Manual or by the city manager or 
designee shall not be planted with the center of their trunks 
closer than 2 feet from any hard surface paving; 
Trees categorized as medium stature on any of the tree lists in 
the Urban Forestry Manual shall not be planted with the 
center of their trunks closer than 2 Yz feet from any hard 
surface paving; 
Trees categorized as large stature on any of the tree lists in 
the Urban Forestry Manual or by the city manager or 
designee shall not be planted with the center of their trunks 
closer than 3 feet from any hard surface paving; 
Where there are overhead utility lines, the tree species 
selected shall be of a type which, at full maturity, will not 
interfere with the lines; and 
9. Where there is existing mature tree canopy or other areas 
with significant shade, the species selected shall be an 
understory tree according to available scientific literature. 
However, understory trees shall only be planted when the 
planting of non-understory trees is precluded due to site 
constraints. 
The location, species, size (in height or container size), assigned 
number and depiction of the mature tree canopy dripline as identified 
in the native tree list in the Urban Forestry Manual (delineated at the 
outer edge of the stand) for all trees to be planted and maintained as 
stand grown trees. The species of trees planted and maintained as 
stand grown trees shall be selected from the native tree list in the 
Urban Forestry Manual. The depiction of the mature tree canopy 
dripline shall be consistent with dimensions in the native tree list. The 
minimum size of stand grown trees shall be 2 feet in height (from the 
top of the root ball) or equivalent to a 1 gallon container size. The city 
manager or designee may consider trees less than 6 inch DBH as 
equivalent to newly planted trees if they meet all applicable species, 
size, condition and location requirements in this section. Overall, the 
selection of stand grown trees shall result in a reasonable amount of 
diversity for the site. Stand grown trees shall be located as follows: 
1. No closer than an average of 10 feet on center from newly 
planted or existing trees; 
2. No further than an average of 20 feet on center from newly 
planted or existing trees; 
Section 10- Urban Forestry Plan Standards 
City of Tigard Urban Forestr y Manual 
City of Tigard Urban l'orc>tn· Code Rc,·isiom I \'olumc 1\' I 40 
I • 
3. Trees categorized as small stature on the native tree list in the 1 Notes: 
Urban Forestry Manual or by the city manager or designee shall 
be spaced no closer than 15 feet from the face of habitable 
buildings. In downtown Tigard (Mixed Use-Central Business 
District, MU-CBD), the setback from the face of habitable 
buildings may be reduced if approved by the city manager or 
designee; 
4. Trees categorized as medium stature on the native tree list in 
the Urban Forestry Manual or by the city manager or designee 
shall be spaced no closer than 20 feet from the face of habitable 
buildings. In downtown Tigard (Mixed Use-Central Business 
District, MU-CBD), the setback from the face of habitable 
buildings may be reduced if approved by the city manager or 
designee; 
5. Trees categorized as large stature on the native tree list in the 
Urban Forestry Manual or by the city manager or designee shall 
be spaced no closer than 30 feet from the face of habitable 
buildings. In downtown Tigard (Mixed Use-Central Business 
District, MU-CBD), the setback from the face of habitable 
buildings may be reduced if approved by the city manager or 
designee; 
6. Trees categorized as small stature on the native tree list in the 
Urban Forestry Manual or by the city manager or designee shall 
not be planted with the center of their trunks closer than 2 feet 
from any hard surface paving; 
7. Trees categorized as medium stature on the native tree list in 
the Urban Forestry Manual shall not be planted with the center 
of their trunks closer than 2 % feet from any hard surface 
pavtng; 
8. Trees categorized as large stature on the native tree list in the 
Urban Forestry Manual or by the city manager or designee shall 
not be planted with the center of their trunks closer than 3 feet 
from any hard surface paving; 
9. Where there are overhead utility lines, the tree species selected 
shall be of a type which, at full maturity, will not interfere with 
the lines; and 
10. Where there is existing mature tree canopy or other areas with 
significant shade, the species selected shall be an understory 
tree according to available scientific literature. However, 
understory trees shall only be planted when the planting of 
non-understory trees is precluded due to space constraints. 
N. Any supplemental specifications that the project arborist or landscape 
architect has determined are necessary for the viability of trees 
proposed for planting. 
0 . A signature of approval and statement from the project arborist or 
landscape architect, attesting that the tree canopy site plan meets all of 
the requirements in Section 10, part 2 of the Urban Forestry Manual. 
.. 
Section 10- Urban F o re s tr y Plan Standard s 
City of Tigard Urban F o re s tr y Manual 
City o f Tigard Urban Fores try Code Rc,·isions I Volume IV I 41 
Page 10-5 
Notes: 
Sec Appendix 9 for 
1\xample 
Supplemental Report 
Template 
Page 10-6 
Part 3. 
A. 
Urban Forestry Plan- Supplemental Report Requirements: 
B. 
c. 
The supplemental report shall be provided by the project arborist or 
landscape architect in paper and PDF format, and include all items in 
part 3.B-P below. 
Date of the report. 
The name, address, telephone number, email address, ISA certified 
arborist number and PNW-ISA certified tree risk assessor number of 
the project arborist or stamp and registration number of the project 
landscape architect. 
D. The following inventory data in table or other such organized format 
corresponding to each tree in parts 1.] and 1.K in the tree preservation 
and removal site plan: 
1. The assigned tree number; 
2. The genus, species and common name; 
3. DBH (in inches) ; 
4. Average tree canopy area (in square feet), calculated as follows : 
a. Average tree canopy area = (average tree canopy 
spread/ 2)2 x n; 
5. Open grown tree or stand grown tree; 
6. Heritage tree? (Y or N); 
7. Numerical condition rating (0-3) as follows: 
Condition Overall Tree Amount of History Pests Extent 
rating vigor canopy deadwood of failure of decay 
density 
- --
0 D ead to <30% Large; major 1'vlore Infested Major; 
severe scaffold than one conks 
decline branches scaffold and 
cavities 
1 Declining 30-60% Twig and Scaffold Infested One to a 
branch branches few 
die back conks; 
small 
cavities 
--- -2 I\ verage 60-90% Small twigs Small lVfinor Present 
branches only at 
prurung 
wounds 
-3 Good to 90- Little or none N one lVfinor to Absent 
excellent 100% Insignificant to 
present 
only at 
prurung 
wounds 
1 
Section 10- Urban For es try Plan Standards 
Cit y of Tigard Urban F o re s try Manual 
City o f Tigard Urban Forestry Code Rc,·isions I \'olumc I\ ' I 42 
I• 
0 
1 
2 
3 
8. Numerical suitability for preservation rating (0-3) as follows: 
ti.tiMril4ihi.J.M 
The tree is a "hazard tree" as defined in Chapter 18.120 of the Tigard 
D evelopment Code and ' 'hazard tree abatement" as defined in Chapter 18.120 
in the Tigard D evelopment Code cannot be completed in a manner that results 
in tree retention consistent with tree care industry standards. 
The tree is dead, in severe decline 
or declining but may be retained if desirable for wildlife or o ther benefits 
because it is not considered a ' 'hazard tree" or "hazard tree abatement" could 
be performed. 
1l1e tree has average health and/ or structural stability that could be alleviated 
with treatment; the tree will be less resilient to development impacts and will 
require more frequent management and monitoring after development than a 
tree rated as a "3". 
The tree has good to excellent health and structural stability; the tree will be 
more resilient to development impacts, and will require less frequent 
management and monitoring after development than a tree rated as a "2". 
9. Proposed for preservation? (Y or N); and 
10. Additional comments. 
E . The following inventory data in table or other such organized format 
corresponding to each existing stand in the tree preservation and 
removal site plan: 
1. The assigned stand number; 
2. The genus, species and common name of the tree spectes 
estimated to be dominant in the stand; 
3. The genus, species and common name of the tree species 
estimated to be the second and third most common in the 
stand; 
4. The estimated average DBH (in inches) of the dominant tree 
species in the stand; 
5. The estimated average DBH (in inches) of both the second and 
third most common tree species in the stand; 
6. The estimated average condition rating (per part 3.D.7) of the 
dominant tree species in the stand; 
7. The estimated average condition rating (per part 3.D . 7) of both 
the second and third most common tree species in the stand; 
8. The total on site tree canopy area (in square feet) of the stand; 
9. Numerical suitability for preservation rating of the stand (0-3) 
as follows: 
S ec ti o n 10 - Urban F o restr y Plan Stand a rd s 
Cit y o f Tigard Urban F o r es tr y Manu a l 
City of Tigard Urban Forestry Code Rc,·isions I Volume IV I 43 
Note~: 
-
Page 10-7 
-- --
N ote" 
0 
L 
1 
2 
3 
l_ --
F. 
G. 
H. 
I. 
]. 
Page 10-8 
HiiliP.U[I 
N uisance trees are the dominant species in the stand and/ or continued viability of 
the stand is unlikely due to pests, diseases, competition from nuisance tree or plant 
species, hydrologic changes or other factors. 
T11e stand requires a currently cost prohibitive level of investment and management 
of pests, diseases, nuisance tree or plant species, hydrology or oth er factors to 
become viable. 
The stand is viable but requires more frequent management and monitoring of pests, 
diseases, nuisance tree or plant species, hydrology or other factors for continued 
viability than a stand rated as a "3". 
The stand is viable and requires less frequent management and monitoring of pests, 
diseases, nuisance tree or plant species, hydrology or other factors for continued 
viability than a stand rated as a "2" . 
10. The total on site tree canopy area (in square feet) of the stand 
proposed for preservation; and 
11 . Additional comments. 
Supplemental specifications regarding the location and type of 
proposed tree protection fencing. If the location of the tree 
protection fencing will be phased, indicate the location of the tree 
protection fencing for each corresponding phase. Tree protection 
fencing shall be minimum 5-foot tall metal unless otherwise approved 
by the city manager or designee. 
Supplemental specifications consistent with tree care industry 
standards that the project arborist or landscape architect has 
determined are necessary for the continued viability of trees 
identified for preservation. 
Supplemental specifications consistent with tree care industry 
standards that the project arborist or landscape architect has 
determined are necessary for the continued viability of stands 
identified for preservation. 
A general accounting of soil characteristics on site. Areas of existing 
or potential tree growth limiting soils due to compaction, drainage, 
fertili ty, pH, contamination or other factors shall be clearly identified. 
Methods for improving areas of tree growth limiting soils if tree 
planting is proposed in those areas shall be specifically addressed. 
The following inventory data in table or other such organized format 
corresponding to each open grown tree proposed for planting in the 
tree canopy site plan: 
1. The assigned tree number; 
2. The genus, species and common name; 
3. The caliper (in inches for deciduous) or height (in feet for 
evergreen); 
Section 10- U rban F o r est r y Plan Standards 
City of Ti ga rd U rban Forestry Manual 
City of T igard Urban l'orc>try Code RcYi>iom I Volume 1\ ' I 44 
4. The average mature tree canopy spread (in feet) as identified on 1 Notes: 
any of the tree lists in the Urban Forestry Manual. If an open 
grown tree approved for planting is not identified on any of the 
tree lists in the Urban Forestry Manual, then the project 
arborist or landscape architect shall determine the average 
matu.re tree canopy spread using available scientific literature 
for review and approval by the city manager or designee; 
5. The average mature tree canopy area (in square feet) calculated 
as follows: 
a. Average mature tree canopy area= (average mature tree 
canopy spread/2)2 x n; 
6. The proposed available soil volume (in cubic feet) for each tree 
according to the methodology in Section 12, part 2 of the 
Urban Forestry Manual. If the available soil volume is greater 
than 1000 cubic feet, then it is OK to note soil volume as 
simply "over 1000 cubic feet"; and 
7. Additional comments. 
K. The following inventory data in table or other such organized format 
corresponding to each stand proposed for planting in the tree canopy 
site plan: 
1. The assigned stand number; 
2. The genus, species and common name of trees proposed for 
planting in the stand; 
3. The average spacing (in feet) and total number of each tree 
species proposed for planting in the stand; 
4. The height (in feet) or container size (in gallons) of each species 
proposed for planting in the stand; 
5. The mature tree canopy dripline area of the stand (in square 
feet) delineated at the outer edge of the stand; and 
6. Additional comments 
L. Any supplemental specifications consistent with tree care industry 
standards that the project arborist or landscape architect has 
determined are necessary for the viability of trees proposed for 
planting. 
M. A summary in table or other such organized format clearly 
demonstrating the effective tree canopy cover that will be provided for 
the overall development site (excluding streets) and for each lot or tract 
in the R-1, R-2, R-3.5, R-4.5 and R-7 districts (excluding streets) as 
follows: 
1. The area (in square feet) of the overall development site and 
each lot or tract; and 
2. The effective tree canopy area that will be provided for the 
overall development site and each lot or tract which shall be 
considered the sum of the following: 
-
Section 10- Urban Forestry Plan Standards 
City of Tigard Urban Forestry Manual 
City of Tigard Urban Forestry Code Revisions I Volume IV I 45 
Page 10-9 
- -
Notes: 
Page 10-10 
a. 
b. 
Double the canopy area (in square feet) of all open 
grown trees in the tree canopy site plan proposed for 
preservation within the overall development site and 
each lot or tract (or associated right of way, excluding 
median trees). Only trees with both a condition rating 
and suitability for preservation rating of 2 or greater 
are eligible for credit towards the effective tree 
canopy cover. The overall development site and each 
lot or tract (or associated right of way) with the largest 
percentage of the trunk immediately above the trunk 
flare or root buttresses shall be assigned the effective 
tree canopy cover area for the corresponding tree; 
Double the canopy area (in square feet) of all stands 
in the tree canopy site plan proposed for preservation 
within the overall development site and each lot or 
tract (or associated right of way, excluding median 
trees). Only stands with both a condition rating and 
suitability for preservation rating of 2 or greater are 
eligible for credit towards the effective tree canopy 
cover. The eligible tree canopy area shall be the 
portion directly above the overall development site 
and each lot or tract (or associated right of way). The 
canopy area of any stand grown tree with the largest 
percentage of the trunk immediately above the trunk 
flare or root buttresses outside of the overall 
development site and each lot or tract (or associated 
right of way) shall not be eligible for credit towards 
the effective tree canopy cover requirement for that 
development site or lot or tract; 
c. The mature canopy area (in square feet) of all open 
grown trees in the tree canopy site plan, except for 
those from the native tree list in the Urban Forestry 
Manual, to be planted and maintained within the 
overall development site and each lot or tract (or 
associated right of way, excluding median trees); 
d. 1.25 times the mature canopy area (in square feet) of 
all open grown trees from the native tree list in the 
Urban Forestry Manual in the tree canopy site plan to 
be planted and maintained within the overall 
development site and each lot or tract (or associated 
right of way, excluding median trees); 
Section 10- U rban Forestr y Plan Standards 
City of Tigard Urban Forestr y Manual 
CitY of Tigard Urban Forc>try Code Rc,-i, iom I \' olumc I\' I 46 
e. 1.25 times the mature canopy area (in square feet) of each stand in 
the tree canopy site plan to be planted and maintained within the 
overall development site and each lot or tract (or associated right of 
way, excluding median trees). The eligible mature tree canopy area 
shall be the portion directly above the overall development site and 
each lot or tract (or associated right of way); and 
f. Divide the tree canopy area (calculated per part 3.M.2.a-e above) 
for the overall development site and each lot or tract by the total 
area of the overall development site and each lot or tract 
respectively to determine the effective tree canopy cover for the 
overall development site and each lot or tract. 
N. The standard percentage of effective tree canopy cover for the overall 
development site shall be at least: 
1. 40 percent for R-1, R-2, R-3.5, R-4.5 and R-7 districts, except 
for schools (18.130.0500)); 
2. 33 percent for R-12, R-25, R-40, C-N, C-C, C-G, C-P, MUE, 
MUE-1, MUE-2, MUC, MUR and I-P districts, except for 
schools (18.130.0500)); and 
3. 25 percent for MU-CBD, MUC-1, I-L and I-H districts, and for 
schools (18.130.0500)) in all districts. 
0 . If the percent of effective tree canopy cover is less than the applicable 
standard percent in item n above for the overall development or less 
than 15 percent for any lot or tract in the R-1, R-2, R-3.5, R-4.5 and R-
7 districts (when the overall development site meets or exceeds the 
standard percent effective tree canopy cover in item n), calculate the 
tree canopy fee required to meet the applicable standard percent 
effective tree canopy cover in item n above for the overall development 
site or 15 percent effective tree canopy cover for each lot or tract in the 
R-1, R-2, R-3.5, R-4.5 and R-7 districts (only if the overall development 
site meets or exceeds the standard percent effective tree canopy cover 
in item n but individual lots or tracts in the R-1, R-2, R-3.5, R-4.5 and 
R-7 districts do provide 15 percent effective tree canopy cover) 
according to the methodology in Section 10, part 4 of the Urban 
Forestry Manual. 
P. A signature of approval and statement from the project arborist or 
landscape architect, attesting that: 
1. The tree preservation and removal site plan meets all of the 
requirements in Section 10, part 1 of the Urban Forestry 
Manual; 
2. The canopy site plan meets all of the requirements in Section 
10, part 2 of the Urban Forestry Manual; and 
3. The supplemental report meets all of the requirements tn 
Section 10, part 3 of the Urban Forestry Manual. 
Part 4. Urban Forestry Plan- Tree Canopy Fee Calculation 
Requirements: 
A. The tree canopy fee shall be calculated as follows: 
-- - ~ -
Section 10- Urban Forestry Plan Standards 
City of Tigard Urban Forestry Manual 
·-- -
City of Tigard Urban Forestry Code Rc1·isions I Volume IV I 47 
Notes: 
Page 10-11 
N otes: 
See Appendix 9 for 
Example 
Supplemental Report 
Template with 
formula for 
calculating the Tree 
Canopy Fcc 
Page 10-12 
1. 
2. 
If the percentage of effective tree canopy cover is less than the 
applicable standard percentage in part 3, item n above for the 
overall development site find the difference (in square feet) 
between the proposed effective tree canopy cover and the 
applicable standard effective tree canopy cover for the overall 
development site and multiply the difference (in square feet) by: 
a. The most recent wholesale median tree cost 
established by the PNW-ISA for a 3 inch diameter 
deciduous tree in the Willamette Valley, OR divided 
by 59 square feet. 
In cases where the overall development site meets the standard 
percentage in part 3.N above yet the percentage of effective 
tree canopy cover is less than 15 percent for any individual lot 
or tract in the R-1, R-2, R-3.5, R-4.5 and R-7 districts, find the 
difference (in square feet) between the proposed effective tree 
canopy cover and 15 percent effective tree canopy cover for 
each deficient lot or tract and multiply the difference (in square 
feet) by: 
a. The most recent wholesale median tree cost established 
by the PNW-ISA for a 3 inch diameter deciduous tree 
in the Willamette Valley, OR divided by 59 square feet. 
Part 5. Urban Forestry Plan- Significant Tree Grove Preservation 
Considerations: 
A. Connects with and does not become isolated from the remaining 
portion of the significant tree grove on or off the site; 
B. Preserves the most dominant, resilient and healthiest native trees; 
C. Preserves a diversity of species, ages and sizes of native trees; 
D . Preserves native understory and supports natural succession; 
E. Preserves and minimizes disturbance to native soils and tree roots; 
F . Does not preserve hazard trees or trees likely to soon become hazard 
trees particularly those subject to windthrow ~ow live crown ratio, 
high height to diameter ratio, suppressed root development) and 
exacerbated by newly created edges and/ or removal of adjacent trees; 
and 
G . Does not preserve trees currendy or likely to soon be severely 
impacted by large scale weed, pest or disease outbreaks and/ or 
changing site conditions (hydrology, light, temperature, wind). 
END OF SECTION 
Section 10- Urban Forestr y Plan Standards 
City of Tigard Urban Forestry Manual 
Citr of Tiga rd Urban Fores try Code Rcr isions I Volume 1\ ' I 48 
Section 11- Urban Forestry Plan Implementation Standards 
Part 1. Urban Forestry Plan Implementation Standards- Inspection 
Requirements: 
A. After tree protection measures are installed and prior to any ground 
disturbance other than what is necessary for the installation of tree 
protection measures and erosion, sediment and pollutant controls 
measures, the project arborist or landscape architect shall perform a 
site inspection for tree protection measures, document 
compliance/ non-compliance with the urban forestry plan and send 
written verification with a signature of approval directly to the city 
manager or designee within one week of the site inspection. 
B. Following the completion of item a above, the project arborist or 
landscape architect shall perform bimonthly (twice monthly) site 
inspections for tree protection measures during periods of active site 
development and construction, document compliance/non-
compliance with the urban forestry plan and send written verification 
with a signature of approval directly to the city manager or designee 
within one week of the site inspection. 
C. When the land use review type will result in the division of land into 
multiple lots or tracts, the applicant shall provide on the building site 
plan for each resulting lot or tract, the information detailed in Section 
10, part 2.B-N of the Urban Forestry Manual consistent with the 
approved urban forestry plan. Prior to issuance of any building 
permits for each resulting lot or tract, the project arborist or landscape 
architect shall perform a site inspection for tree protection measures, 
document compliance/non-compliance ~vith the urban forestry plan 
and send written verification with a signature of approval with the 
building permit submittal documents. 
D . When the land use review type will result in the division of land into 
multiple lots or tracts, the project arborist or landscape architect shall 
perform a site inspection for tree protection measures for all lots or 
tracts that are not proposed to be associated with a building permit, 
document compliance/non-compliance ~vith the urban forestry plan 
and send written verification with a signature of approval to the city 
manager or designee prior to the issuance of the first building permit 
resulting from the land use review type. 
E. Prior to final building inspection for any lot or tract with an active 
urban forestry plan, the project arborist or landscape architect shall 
perform a site inspection, document compliance/non-compliance 
with the urban forestry plan and send written verification with a 
signature of approval to the city manager or designee. 
Section 11- Urban Forestr y Plan Implementation Standards 
City of Tigard Urban Forestry Manual 
·- - ---- - -
City o f Tigard Urban Forestry Code Re,·isions I Volume IV I 49 
Notes: 
See Appendix 10 for 
Example Tree 
Canopy Site Plan 
(Section 10, Part 2) 
for an Individual Lot 
Page 11-1 
-
Note~: 
Sec l\h~ rcr Fees and 
Cha rge~ schedule fo r 
current fees 
Page 11-2 
Part 2. Urban Forestry Plan Implementation Standards- Tree 
Establishment Requirements: 
A. Prior to any ground disturbance work, the applicant shall provide a 
tree establishment bond for all trees to be planted per the approved 
urban forestry plan. The total bond amount shall be equivalent to the 
city's average cost to plant and maintain a tree per the applicable 
standards in the Urban Forestry Manual for a period of two years after 
planting multiplied by the total number of trees to be planted and 
maintained. 
B. Following final building inspection or upon acceptance by the city 
manager or designee when there is no final building inspection, the 
tree establishment period shall immediately begin and continue for a 
period of two years. 
C. When the land use review type will result in the division of land into 
multiple lots or tracts, there shall be a separate tree establishment 
period for each resulting lot or tract where trees are shown to be 
planted in the approved urban forestry plan. 
D . Following the two year tree establishment period for each lot or tract, 
the bond shall be correspondingly reduced based on tree survival 
following a site inspection, documentation of successful tree 
establishment and/ or replacement according to item e below, and 
receipt by the city manager or designee of written verification of 
findings and a signature of approval by the project arborist or 
landscape architect. 
E. For planted open grown trees, successful establishment shall be 
considered 80 percent survival of the open grown trees planted on the 
lot or tract, and replacement of 100 percent of the remaining open 
grown trees planted on the lot or tract that did not survive. 
F. For planted stand grown trees, successful establishment shall be 
considered survival of at least 80 percent of the original stand grown 
trees planted on the lot or tract. 
G. If successful establishment for open grown trees is less than 80 
percent for any lot or tract, the two-year tree establishment period 
shall reset for that lot or tract and the establishment process for open 
grown trees described in part 2.B-F above shall be repeated until the 
successful establishment requirement for open grown trees is met. 
H . If successful establishment for stand grown trees is less than 80 
percent for any lot or tract, the two-year tree establishment period 
shall reset for that lot or tract and the establishment process for stand 
grown trees described in Part 2.B-F above shall be repeated until the 
successful establishment requirement for stand grown trees is met. 
Section 11- Urba n Forestry Plan Impl ementation Standards 
City of Tigard Urban Forestry Manual 
City of Tigard Urban l;orc,try Code Rc,·isiom I \ 'olumc I\ ' I 50 
Part 3. Urban Forestry Plan Implementation Standards- Urban Forest 
Inventory Requirements: 
A. Following documentation of compliance with the urban forestry plan 
by the project arborist or landscape architect for each lot or tract, the 
city shall collect spatial and species specific data for each open grown 
tree and area of stand grown trees for inclusion in a publicly accessible 
inventory of trees. 
B. Prior to any ground disturbance work, the applicant shall provide a fee 
to cover the city's cost of collecting and processing the inventory data 
for the entire urban forestry plan. 
END Of SECTION 
Section 11- Urban Forestry Plan Implementation Standards 
City of Tigard Urban Forestry Manual 
City o f Tigard Urban Forestry Code RcYisions I Volume IV I 51 
Notes: 
See Master Fees and 
Charges Schedule for 
current fees 
Page 11-3 

Part 1. 
A. 
Section 12 - Street Tree Soil Volume Standards 
Street Tree Soil Volume Standards - Soil Volume Requirements: 
Street trees required to be planted by chapter 18.745 shall be provided 
the following minimum soil volumes based on the width of the 
proposed right of way measured from the edge of the street (excluding 
curb) towards the subject site: 
Minimum Soil 
Right ofWay Width Volume Requirement 
(feet) (cubic feet per tree) 
Up to 10 400 
O ver 10 up to 12 500 
Over 12 up to 14 600 
Over 14 up to 16 700 
Over 16 up to 18 800 
Over 18 up to 20 900 
Over 20 1000 
Part 2. Street Tree Soil Volume Standards - Soil Volume Calculation 
Requirements: 
A. For open soil volumes, soil depth is assumed to be 3 feet if the tree 
canopy site plan (per 18.790.030.A.3) and supplemental report (per 
18.790.030.A.4) demonstrate that the tree will not be planted in an 
area of tree growth limiting soil or the area of tree growth limiting soil 
will be adequately amended to a depth of 3 feet in the specified 
planting area. 
B. Areas of tree growth limiting soils that have not been adequately 
amended shall not be eligible for credit towards the minimum soil 
volume requirements in part 1 of this section. 
C. For covered soil volumes, the soil depth is equal to the depth of the 
covered soil volume as demonstrated by the soil volume plan in part 3 
of this section. 
D. Soil volumes for open soil volumes shall be calculated (in cubic feet) 
by measuring the open soil volume area (in square feet) times an 
assumed soil depth of 3 feet. 
E. Soil volumes for covered soils volumes shall be calculated (in cubic 
feet) by multiplying the area of the covered soil volume times the depth 
of the covered soil volume as demonstrated by the soil volume plan in 
part 3 of this section. 
F. The total soil volume provided for a tree shall be calculated (in cubic 
feet) by adding the available open soil volume (per part 2.C above) to 
the available covered soil volume (per part 2.D above) within a 50 foot 
radius of the tree. 
Section 12- Street Tree Soil Volume Standards 
Cit y of Tigard Urban Forestr y Manual 
City of Tigard Urban Fores try Code Rc,-isions I Volume IV I 53 
Notes: 
See Appendix 11 for 
three Example Soil 
Volume Calculations 
for Street Trees 
Page 12-1 
Notes: 
See Appendix 12 for 
Example Soil 
Volume Plan 
See Appendix 14 for 
two alternative 
Example Covered 
Soil Volume Plan 
Drawings and an 
Example Covered 
Soil Specification for 
Street Trees 
Sec Appendix 13 for 
Example Soil 
Volume Plan for a 
Single J ,ot 
Page 12-2 
G. 
H. 
I. 
The open and covered soil volumes are considered "available" to a 
tree only when they are directly connected to the tree by a continuous 
path of no less than 3 feet in width. 
In addition, covered soil volumes are considered "available" to a tree 
only when demonstrated as available by the soil volume plan in part 3 
of this section. 
All soil volumes calculated per this section shall be displayed for each 
corresponding tree in the required supplemental report. 
Part 3. Street Tree Soil Volume Standards- Soil Volume Plan 
Requirements: 
A. A soil volume plan shall be required for any street tree required to be 
planted by chapter 18.745 if a covered soil volume is proposed to be 
used to meet any portion of the minimum soil volume requirements in 
part 1 of this section. The soil volume plan shall include all items in 
part 3.B-E below. 
B. A standard size D (24" x 36"), a reduced legal size and a PDF soil 
volume plan by a registered landscape architect (the project landscape 
architect) that includes all of the following elements: 
1. Date of drawing or last revision; 
2. North arrow; 
3. Bar scale; 
4. Site address or assessor's parcel number; 
5. The name, address, telephone number, email address and 
license number of the project landscape architect; 
6. The location of property lines or proposed property lines if 
different from existing; 
7. The location of proposed building footprints , utilities and 
irrigation, streets and other paved areas; 
8. The assigned numbers (consistent with the tree canopy site plan 
and supplemental report of a concurrent urban forestry plan) of 
all trees; 
9. The location of each open soil volume area and each covered 
soil volume area considered "available" for each tree; and 
10. The City of Tigard Example Covered Soil Volume Plan 
Drawings and Specifications unless otherwise approved by the 
city manager or designee. If required for clarity, this 
information may be detailed on a separate plan sheet. 
C. When the land use review type will result in the division of land into 
multiple lots or tracts, the applicant shall provide on the building site 
plan for each resulting lot or tract, the information detailed in -part 
3.B.1-1 0 of this section consistent with the approved soil volume plan 
and a signature of approval from the project landscape architect. 
Section 12- Street Tree S o il Volume Standards 
City of Tigard Urban Forestr y Manual 
City of Tigard Urban l;orcstry Code Rc,·isions I \'olumc 1\ ' I 54 
D. 
E. 
The project landscape architect shall document compliance/non-
compliance (includillg but not limited to materials receipts and 
observations from site inspections) with the approved soil volume plan, 
and send written verification with a signature of approval to the city 
manager or designee prior to final buildillg inspection for all lots, 
parcels, or tracts associated with each particular tree. When the land 
use review type will result in the division of land into multiple lots or 
tracts, the project landscape architect shall provide the 
documentation/verification described above for all lots or tracts that 
are not proposed to be associated with a buildillg permit prior to the 
issuance of the first buildillg permit resulting from the land use review 
type. When the land use review type does not involve a buildillg 
permit, the project landscape architect shall provide the 
documentation/verification described above prior to final acceptance 
by the city manager or designee. 
If any subsequent modifications to an approved soil volume plan is 
required to meet the minimum soil volume requirements in part 1 of 
this section, a revised soil volume plan that meets the requirements of 
part 3 of this section shall be provided that reflect the revisions. 
END OF SECTION 
Section 12- Street Tree Soil Volume Standards 
City of Tigard Urban Forestry Manual 
City of Tigard Urban Forestry Code Revisions I Volume IV I 55 
Notes: 
Page 12-3 
"
 
E :J 
c ::.-
--
Section 13 - Parking Lot Tree Canopy Standards 
Part 1. Parking Lot Tree Canopy Standards - Parking Lot Tree 
Requirements: 
A. 
B. 
c. 
D . 
E. 
F. 
Parking lot trees shall be planted in a manner consistent with tree care 
industry standards. 
Parking lot trees shall have a minimum caliper of 1 Yz inches (for 
deciduous) or height of a 6 feet (for evergreen) at the time of planting. 
Parking lot tree species shall be from the parking lot tree list, unless 
otherwise approved by the city manager or designee. 
Parking lot trees shall not be planted with the center of their trunks 
closer than 3 feet from any hard surface paving, including curbs. 
Parking lot trees shall be evenly distributed within the parking area, 
and no greater than 6 feet from the parking area. 
Parking lot trees shall be provided a minimum of 1000 cubic feet of 
soil volume per tree. 
Part 2. Parking Lot Tree Canopy Standards - Soil Volume Calculation 
Requirements: 
A. Soil volumes for open soil volumes shall be calculated (in cubic feet) 
by measuring the open soil volume area (in square feet) times an 
assumed soil depth of 3 feet. 
B. Soil volumes for covered soils volumes shall be calculated (in cubic 
feet) by multiplying the area of the covered soil volume times the 
depth of the covered soil volume as demonstrated by the parking lot 
tree canopy plan in part 3 of this section. 
C. The total soil volume provided for a tree shall be calculated (in cubic 
feet) by adding the available open soil volume (per part 2.A above) to 
the available covered soil volume (per part2.B above) within a 50 foot 
radius of the tree. 
D. The open and covered soil volumes are considered "available" to a 
tree only when they are direcdy connected to the tree by a continuous 
path of no less than 3 feet in width, and demonstrated as available by 
the parking lot tree canopy plan in part 3 of this section. 
E. All soil volumes calculated per this section shall be displayed for each 
corresponding tree in the supplemental report (per 18.790.030.A.4) 
when an urban forestry plan is concurrendy required. 
Part 3. Parking Lot Tree Canopy Standards - Parking Lot Tree Canopy 
Plan Requirements: 
A. A parking lot tree canopy plan shall be required unless the city 
manager or designee determines the requirements of a concurrent 
urban forestry plan per chapter 18.790 will meet the equivalent 
standards in part 3 of this section. The parking lot tree canopy plan 
shall include all items in part 3.B-E below. 
Section 13- Parking L ot Tree Canopy Standards 
City of Tigard Urban Forestry Manual 
City o f Tigard Urban Forestry Code Re,·isions I Volume IV I 57 
Notes: 
See Appendix 3 for 
Parking Lot Tree List 
See Appendix 15 for 
three Example Soil 
Volume Calculations 
for Parking Lot 
Trees 
See i\ ppcndix 16 for 
Example Parking Lot 
Tree Canopy Plan 
Page 13-1 
----- --
Notes: 
Sec i\ ppcndix 17 for 
two alternative 
Example Covered 
Soil Volume Plan 
Drawings and an 
Example Covered 
Soil Specification for 
Parking Lot Trees 
See Appendix 18 for 
Example Parking Lot 
that Meets the 30% 
1\linimum Canopy 
Cover Requirement 
per Code Section 
18.745.050.E. 1.a.4 
Page 13-2 
B. 
c. 
A standard size D (24" x 36"), a reduced legal size and a PDF parking 
lot tree canopy plan by a registered landscape architect (the project 
landscape architect) that includes all of the following elements: 
1. Date of drawing or last revision; 
2. North arrow; 
3. Bar scale; 
4. Site address or assessor's parcel number; 
5. The name, address, telephone number, email address and 
license number of the project landscape architect; 
6. The location of property lines or proposed property lines if 
different from existing; 
7. The location of proposed building footprints, utilities and 
irrigation, streets and other paved areas; 
8. The location of areas of tree growth limiting soils due to 
compaction, drainage, fertility, pH, contamination or other 
factors; 
9. Methods for improving areas of tree growth limiting soils if tree 
planting is proposed in those areas. If required for clarity, this 
information may be detailed on a separate plan sheet; 
1 0. The location of all parking lot striping and the location of the 
limits of the parking area, which includes all parking spaces, all 
landscape islands and all parking aisles; 
11. Assigned numbers (consistent with the tree canopy site plan per 
18.790.030.A.3 and supplemental report per 18.790.030.A.4 of a 
concurrent urban forestry plan) of all parking lot trees; 
12. The location, species and caliper (in inches for deciduous) or 
height (in feet for evergreen) of all parking lot trees; 
13. Depiction of the average mature tree canopy spread (in feet as 
identified on any of the tree lists in the Urban Forestry Manual) 
for each parking lot tree. If a parking lot tree is not identified 
on any of the tree lists in the Urban Forestry Manual, then the 
project arborist or landscape architect shall determine the 
average mature tree canopy spread using available scientific 
literature for review and approval by the city manager or 
designee; 
14. The location of each open soil volume area and each covered 
soil volume area considered "available" for each tree; and 
15. If covered soil volumes are proposed to meet any portion of 
the soil volume requirement in part 1.F of this section, the City 
of Tigard Example Covered Soil Volume Plan Drawings and 
Specifications unless otherwise approved by the city manager or 
designee. If required for clarity, this information may be 
detailed on a separate plan sheet. 
A summary in table or other such organized format clearly 
demonstrating the proposed percent tree canopy cover at maturity 
directly over the parking area as follows: 
1. The area (in square feet) of the parking area as shown in the 
parking lot tree canopy plan; 
Section 12- Parking Lot Tree Canopy Standards 
Cit y of Tigard Urban Forestr y Manual 
City of Tigard Urban I ;orc, trv Code Rn i,iom I \' olumc I\' I 58 
2. The average mature tree canopy area for each parking lot tree 
as follows: 
a. Average mature tree canopy area= (average mature tree 
canopy spread/2/ x n; 
3. The total combined mature tree canopy area (in square feet) of 
all parking lot trees less the percentage not directly over the 
parking area; and 
4. The total combined mature tree canopy area directly over the 
parking area (in square feet) divided by the parking area. 
D . The project landscape architect shall document compliance/non-
compliance (including but not limited to materials receipts and 
observations from site inspections) with the approved parking lot tree 
canopy plan, and send written verification with a signature of approval 
to the city manager or designee prior to final building inspection or 
prior to final acceptance when there is no final building inspection. 
E . If any subsequent modifications to an approved parking lot tree canopy 
plan is required, a revised parking lot tree canopy plan that meets the 
requirements of part 3 of this section shall be provided that reflect the 
revtstons. 
END OF SECTION 
Section 13- Parking Lot Tr ee Can o p y Standards 
City of Tigard Urban Fore s tr y Manu a l 
City of Tigard Urban Forestry Code Rc,·isions I Volume IV I 59 
Notes: 
Page 13-3 
'
-c 
City ofTigard 
Tree Risk Assessment Form 
!·Iazard Rating: 
Probability + The Target + Siz~ of 
o f l'ailurc Area DdcctiY~ Part 
Recommended Hazard Tree Abatement 
Ov~rall Risk 
Rating 
Procedures: ______________________________________________________________________________ __ 
Property Address: ____________________ _ 
Location: 0 Public 0 Private 0 Right-of-Way 
Protected Tree: 0 Yes 0 No 
Tree Species: _____________________ __ 
Diameter at Breast Height (DBH): ____________ _ 
Tree Height: ______________________ __ 
Crown Spread: _____________________ _ 
TreePartSu~~tofEv~uation: ____________________________ ~ 
Diameter of Subject Tree Part: _____________________________ _ 
Distance to Target of Subject Tree Part: __________________________ ~ 
Length of Subject Tree Part: ______________________________ __ 
Target: ______________________________________ __ 
Occupancy of Target: 0 Occasional Use 0 Intermittent Use 0 Frequent Use 0 Constant Use 
Date of Evaluation: 
Certified Tree Risk Assessor: 
Certificate Number: 
ISA Number: 
Certified Tree Risk Assessor Signature: ____________________________________ _ 
*Fill out this and supplemental rating form completely and attach: 1) photos of the tree; 2) an aerial photo showing the 
location of the tree on the subject property; and 3) a supplemental tree risk assessment report more fully describing 
whether the definition of hazard tree has been met and, if necessary, recommended hazard tree abatement procedures. 
Appendix 1 
City of Tigard Urban Forestry Code Re,·isions I Volume IV I 61 

Probability of Failure (1 - 5 r.oints) I c·h 
One 
- --- -
Low Defect is not likely to lead to Minor branch or crown dieback, small wounds, minor defects. 
1 point imminent failure, and no further 
action is reguired. ln many cases, 
defects mi ht not be recorded. 
Moderate O ne or more defects areas well- Several defects present. 
2 points established but typically do not lead to • Shell wall exceeds minimum rcguirement 
failure for several years. Corrective • Cracks initiated but no extensive decay 
action might be useful to prevent • Cavity opening or other stem damage less than 30% of circumference 
futu re problems but only if time and • Crown damage or breakage less than 50~ o of canopy (30~ o in pines) 
money are available. Not the highest . Dead crown limbs with fmc twigs attached and bark intact 
priority for action, these are retain and • Weak branch union such as major branch or codominant stem with 
monitor situations used to inform included bark 
budget and work schedules for • Stem girdling roots with less than 40~ o o f circumference compressed 
subseguent years. • Root damage or root decay affects less than 33% of roots within the 
critical zone 
• Standing dead tree that is recently dead (still has fine twigs) and no 
other si ificant defects 
Moderately One or more defects areas well- Areas of decay that may be expanding; trees that have developed a recent 
H igh established, but not yet deemed to be but not yet critical lean; cracks noted but may be stable; edge trees that 
3 points a high priority issue. Additional may adapt and become more stable. 
testing may be reguired or, the 
assessor may feel the problems are 
not serious enough to warrant 
immediate action, but do warrant 
placing the tree on a list of trees to be 
inspected more regularly. 'These are 
Retain and Monitor trees. 
High The defect is serious and imminent One or more major defects present. 
4 points failure is likely and corrective action is . Insufficient shell wall thickness 
reguired immediately. ·rnese cases • Large cracks, possibly associated with other defects 
reguire treatment within the next few • Cavity opening greater than 3~ o of circumference 
days or weeks. • Crown damage or breakage more than 5~ o o f canopy (> 3~ o in 
pines) 
. Dead crown limbs with no fine twigs and bark peeling away. May be 
some saprophytic fungal evidence 
• Weak branch union has crack(s) or decay 
• Stem girdling root affects ~ o or more of trunk circumference 
• More than 33~ o of roots are damaged within the critical zone 
• Tree is leaning. Recent root breakage, or soil mounding, or cracks, 
or extensi,·e decay evident 
• Standing dead tree, has very few fine twigs, and no other significant 
defects 
Extrem e The tree or component part is already Multiple high or extreme risk defects present. 
5 points failing. An emergency situation where • Shell wall is already cracked and failing 
treatment is reguired today. • Major cracks already open, such as hazard beams or split trunks 
• More than 30% of circumference defective and cracks or decay 
obvious 
• Dead crown limbs, no fmc twigs, no bark, decay present 
• Weak branch union has crack(s) and decay 
• Leaning tree with recent root failure, soil mounding, and cracks 
or extensive decay 
• Dead branches hung up or partly failed 
• Visual obstruction of traffic signs/lights at intersections 
• Any partly failed component or whole tree 
• Standing dead trees that have been dead for more than one season 
with 
multi le defects such as cracks, decay, dama ed roots, sheddin bark 
Appendix 1 
City of Tigard Urban Forestry Code Revisions I Volume IV I 63 
Low 
1 point 
Moderate 
2 point~ 
Moderatel 
y 
High 
3 points 
High 
4 points 
Site~ rated at one point arc very rarely used for any long period of time, and people passing through the 
area (regardless of how they travel) do not spend a lot of time within the striking range of the tree. 
There are no valuable buildings or other facilitic~ within striking range. Examples are seldom used back 
country roads or trails, seldom used overtlow or long-term parking, industrial areas where workers drive 
machines (trucks, forklifts, tractors) with substantial cab protection; natural or wilderness areas; 
tran~ition area~ with limited access; remote areas of yards, parks, or private lands open for public use 
within set hours. t\ll of these sites have rdatively low occupancy within any one day. 
Valuable building~ arc at the edge off the striking distance, ~o they would not be seriously damaged even 
if the tree did fall down. The site has people within striking range occasionall y, meaning l c~~ than 50% 
of the time span in any one day, week, or month, and do not stay within striking range very long. 
Examples include areas that arc used seasonally; more remote areas of camping areas o r parks; minor 
rural roads; picnic areas; low to moderate usc trail s; most park and school playgrounds.** Moderate to 
low u~c parks, parking lot~ with daily usc; secondary roads and intersections , dispersed camping sites, 
moderate to high usc trails , works and / or storage _yards. 
The site has valuable buildings within striking range. People are within striking range more than 50% of 
the time span in any one day, week, or month, and their exposure time can be more than just passing 
by. Examples include secondary roads, trails, and access points; less commonly used parking areas and 
trails within parks; trails alongside fairways, bus stops. 
The highest rated targets have a) a building within striking range frequently accessed by people, often 
for longer period ~ of time, o r high volumes of people coming and going within ~triking range. Valuable 
building~ or other structures within striking range that would suffer major structural damage in the 
event o f tree failure o r; b) people within striking di~tancc o f the tree, o r both, seven dap a week, all year 
long, and at all times of the day. Examples include main roads, the busiest streets or highways; high 
volume intersections power lines;* path ~ through busy open space areas and parks; short-term parking 
constantly in u ~c; in>titutional buildings such a~ police ~ration> , hospitals, fire stations; shopping area~; 
highly u~ed walking trails; pick up and drop off points for commuters; golf tees and greens; emergency 
acccs~ routes and / or marshalling areas; handicap access areas; high usc camping areas, visitor centers o r 
~ helters ; residential buildings; industrial area~ where worker~ take outside breaks; development sites 
where work activity within ~triking range l a~t~ more than a few hour~ at a time. 
1" 
*There arc very specific ,;afc work practices required when working close to Power Lines. Th ese vary depending on location, but 
all employ sin1ilar prin ciple~. 
** It is recognized that there is a tendency to rate playgrounds higher simply because children arc involved. Most playgrounds arc 
occupied for short periods of time in daylight hours. Overall , their usc is infrequent when compared to other locations such 
a~ busy streets. 
~ 
1 point Branches or stems up to 10 centimeters (4 inches) in diameter 
2 points Branches or stems between 10 to 50 centimeters (4 to 20 inches) in diameter. 
T-- I 
3 points Branches or stems greater than 50 centimeters (20 inches) in diameter. I --1 
*In some cases, there may be large areas of sloughing back bark, dwarf mistletoe brooms, branch stubs, o r large bird nes ts in 
cavitie~ that po>c a risk. The asse,;sor must usc his or her judgment to assign a number to these components. In general, the 
lowe~ t rating (1 point) is reserved for component parts that would no t create much impact on a person or property if it were to 
fail. The highest rating i> used for parts that have the po tential to kill people or seriously damage property. 
Appendix 1 
Cit1· of Tigard Urban l ;or~stn· Code R~1· i sions I \ 'olumc 1\' I (,4 
9 
10 
11 
12 
Risk C11.tegory 
Low1 
Low2 
Low3 
Moderate 1 
Moderate 2 
l]fj 
Interpret:ltion 11.nd Implic11.tions 
Insignificant- no concern at all. 
Insignificant- very minor issues. 
Insignificant- minor issues not o f concern for many years yet. 
Some issues but nothing that is likely to cause any problems for another 10 years 
or more. 
Moderate 3 -l 
Well defined issues- retain and monitor. Not expected to be a problem for at 
least another 5-10 years. 
\'(/ell defined issues- retain and monitor. Not expected to be a problem for at 
least another 1-5 years. 
High 1 
High 2 
High 3 
Extreme 
The assessed issues have now become very clear. The tree can still reasonably be 
retained as it is not likely to fall apart right away, but it must now be monitored 
annually. At this stage, it may be reasonable for the risk manager/owner to hold 
public education sessions to in form people of the issues and prepare them for the 
reality that part or the entire tree has to be removed. 
The assessed issues have now become very d ear. The probability of failure is 
now getting serious, or the target rating and / or site context have changed such 
that mitigation measures should now be on a schedule with a clearly defined 
timeline for action. There may still be time to inform the public of the work 
being planned, but there is not enough time to protracted discussion about 
whether or not there are alternative options available. 
The tree, or a part of it has reached a stage where it could fail at any time. 
Action to mitigate the risk is required within weeks rather than m onths. 
By this stage there is not time to hold public meetings to discuss the issue. Risk 
reduction is a clearly defined issue and although the owner may wish to inform 
the public of the planned work, he/ she should get on with it to avoid clearly 
foreseeable liabilities. 
r 
This tree, or part of it, is in the process of failing. Immediate action is 
required. All other, less significant tree work should be suspended, and roads or 
work areas should be dosed off, until the risk issues have been mitigated. This 
might be as simple as removing the critical part, drastically reducing overall tree 
height, or taking the tree down and cordoning off the area until final dean up, or 
complete removal can be accomplished. The immediate action required is to 
ensure that the clearly identified risk of harm is eliminated. For areas hit by 
severe storms, where many extreme risk trees can occur, drastic pruning and / or 
partial tree removals, followed by barriers to contain traffic, would be an 
acceptable first stage of risk reduction. There is no time to inform people or 
worry about public concerns. Clearly defined safety issues preclude further 
discussion. 
The Table shown above outlines the interpretation and implications of the risk ratings and associated risk categories. This table 
is provided to inform the reader about these risk categories so that they can better understand any risk abatement 
recommendations made in the risk assessment report. 
Notes:--- --------- -------------- - - -------= = ========== 
Appendix 1 
City of Tigard Urban Forestry Couc Rc,·isions I Volume IV I 65 

Street Tree List - Small Stature Trees 
to 25' in hei 
Eap~:rb~rk M~plc At"erg1ismm 25' 25' 491 sq. ft. all Yes* 
Tatarian J\lapk Aar tatmimm 20' 20' 314 sq. ft. all Yes 
Trids:nt Map!~ Am· bllergera/1/IIJJ 25' 20' 314 sq. ft. all Yes 
:>~rvi~s:b~n)' A111elant'hier x grcwrliflom 25' 15' 177 sq. ft. well drained Yes 
W~H~rg :>crvi~~bm:~ Amelambier a!nifolia 20' 20' 314 sq. ft. loam Yes 
il.m~ri~a!l llowhcam Cmpinlls mroliniana 25' 20' 314 sq. ft. all No 
~ EaH~:rg B.s:db!.!d Cenis canadensis 25' 25' 491 sq. ft. all Yes 
~~ - GIQ!:yblo'Y~[ h~~ Clerorlmrlmm l!idJotomllm 20' 20' 314 sq. ft. all Yes 8., 
Kol.!sa I2o~ood Com11s kousa 25' 25' 491 sq. ft. all Yes 
c@ Flmverin!' Dogwood Con111S jl01irla 25' 25' 491 sq. ft. all Yes a. 
c 
a- Lavalle I Iawthorne Cmtaegus x lauallei 25' 20' 314 sq. ft. all Yes 
" :l 
c) ' 
fl Black I !awthorne Crataeg11s rlo11g,lasii 25' 20' 314 sq. ft. all Yes q 
"< Golden Desert Ash Fraximts exa:lsior 'Golden D esert' 20' 20' 314 sq. ft. all Yes 
n 
0 Flowering t\sh Fmxin11s on11ts 25' 25' 491 sq. ft. all Yes 0.. 
"' :;;:; Merrill Magnolia Magnolia x loebneri 'Merrill' 25' 25' 491 sq. ft. all 0 
"' 
"' :n · c; · 
::lomhm1 Magnolia Magnolia granrliflora 'Victoria' or 'Little Gem' 25' 25' 491 sq. ft. all No ~ 
< Em:i~:fu;s;: Crab~ppk Mal11s spp. 'Prariefu:e' 20' 20' 314 sq. ft. all Yes 0 25' 25' 491 sq. ft. loam No c 
3 25' 25' 491 sq. ft. well drained Yes ,.., 
< 20' 15' 177 s . ft. well drained Yes 
c-
..... 
*These trees have been approved by Pordand General Electric 
(PGE) for p lanting beneath overhead powerlines 
> 
'"0 
'"0 ('D 
~ 
~ 
>< 
N 
peeling bark, tolerates some shade 
tolerant of urban stresses 
tolerant of urban stresses 
white flowers, edible fruit 
native to Portland metropolitan region 
needs ample water 
pink flowers in spring before leaves emerge 
colorful flowers in summer, blue berries in fall 
shade tolerant 
large number of varieties available 
white flowers in May, orange-red fruit persist 
into Winter 
native to Portland metropolitan region, has 
thorns 
golden twigs 
fragrant flowers 
fragrant white flowers 
broad leaf evergreen, large fragrant white flowers 
disease resistant 
needs ample water 
white flowers hang down from branches 
sho 
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l ~ !.!rop!,;aniiQrnb~am 
K a t w r a  
Y c l l o w w o o d  
, I  ~~n~ S n o w  DQ~>wood 
Pa~i fi~ D Q ! J ' \ ' i Q O d  
D o v e  T r e e  
R a ) ' W o o d  .  \  s  h  
C o l d e n q i n  T r e e  
Y v l a n  i ' l l a v n o l i a  
~Quth~rn M a ! ! P Q l i a  
S o ! . J ! ' \ v o o d  
l\m~ri~~n I  lQphornb~am 
P~r~t~n ParrQtt~ 
1\ m u r  C o r k t r c c  
C a l l e r y  P e a r  
C a s c a r a  
F r o n n c r  U m  
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: : l  
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A t e r  m m p e s t r e  
A t e r  t m n m / 1 1 / J I  x  A c e r p l a t a n o i d e s  
A r lm t m  ' M a r i n a  
'  
C a rp i n 1 1 s  b e t 1 1 1 1 1 s  
C e n i d i p ll ) ' I I I I I J I  j a p o n i m m  
C ! a d m s l i s  k m t m k i a  
C o m 1 1 s  w n l r o ! Je r s a  ' ]  u n e  S n o w '  
C o n 1 1 1 S  I I  I I  I t a / Ii i  
D f l l ; i d i a  t / 1 / Jo / m m t a  
F m .\ . ' i i i i i S  O.' J ' < ' f l rp a  ' R a y w o o d '  
Koelrrmte~ia p a n i m l a t a  
, \  l ag n o l i a  d m 1 1 d a t a  
M a g n o l i a  g m n d i f ! o m  ' E d i t h  B o g u e '  
Q . ,y d m d m m  arbo'~"''' 
O s t o •a  IJi rg i n i a n a  
P rm v t i a  p e r s i m  
P b e / l o d m d r o n  a ! J / 1 / I r ! J S e  
l~yms a ! l l e o ' a " a  
R /} (1 1 / J I I I I S  p 1 1 r s b i a n a  
U l m n s  ' F r o n t i e r '  
S t r e e t  T r e e  L i s t - M e d i u m  S t a t u r e  T r e e s  
b e t w e e n  2 5 '  a n d  4 0 '  i n  h e i  
3 5 '  3 0 '  7 0 7  s q .  f t .  a l l  N o  t o l e r a n t  o f  u r b a n  s t r e s s e s  
3 5 '  2 5 '  
4 9 1  s q .  f t .  a l l  N o  
m a n y  v a r i e t i e s  a v a i l a b l e  
3 0 '  3 0 '  
7 0 7  s q .  f t .  
a l l  N o  b r o a d l e a f  e v e r g r e e n  
3 5 '  
2 5 '  
4 9 1  s q .  f t .  a l l  N o  
d e n s e  c r o w n  
4 0 '  
4 0 '  1 2 5 6  s q .  f t .  a l l  N o  
r e q u i r e s  m o i s t  s o i l s  
3 5 '  3 5 '  
9 6 2  s q .  f t .  a l l  
N o  f r a t , > r a n t ,  w h i t e ,  p e n d u l o u s  f l o w e r s  
3 0 '  3 5 '  9 6 2  s q .  f t .  w e l l  d r a i n e d  N o  w i d e  s p r e a d i n g ,  f l o w e r s  i n  M a y / J u n e  
n a t i v e  t o  P o r t l a n d  m e t r o p o l i t a n  r e g i o n ,  require~ 
4 0 '  3 0 '  7 0 7  s q .  f t .  l o a m  N o  m o i s t  s o i l  a n d  s o m e  s h a d e  
3 5 '  3 0 '  7 0 7  s q .  f t .  
w e l l  d r a i n e d  
N o  
d o v e - l i k e  f l o w e r s  
3 5 '  3 0 '  
7 0 7  s q .  f t .  
a l l  
N o  
s m o g  t o l e r a n t  
3 5 '  3 5 '  9 6 2  s q .  f t .  a l l  N o  t o l e r a n t  o f  u r b a n  s t r e s s e s  
3 5 '  3 0 '  7 0 7  s q .  f t .  a l l  N o  
w h i t e ,  f r a g r a n t  f l o w e r s  
b r o a d  l e a f  e v e r g r e e n ,  m a n y  o t h e r  v a r i e t i e s  
3 5 '  2 0 '  3 1 4  s q .  f t .  a l l  N o  
a v a i l a b l e  
3 0 '  
~o· 
3 1 4  s q .  f t .  
w e l l  d r a i n e d  
N o  
w h i t e ,  m i d s u m m e r  f l o w e r s  
3 5 '  2 5 '  4 9 1  s q .  f t .  a l l  N o  
e x f o l i a t i n g  b a r k  t e x t u r e  i s  a t t r a c t i v e  
3 5 '  2 5 '  4 9 1  s q .  f t .  w e l l  d r a i n e d  N o  
b e a u t i f u l  b a r k  a n d  f a l l  c o l o r  
4 0 '  3 0 '  
7 0 7  s q .  f t .  
a l l  N o  
f r a g r a n t  l e a v e s  a n d  f r u i t  
4 0 '  2 5 '  4 9 1  s q .  f t .  a l l  N o  
m a n y  v a r i e t i e s  a v a i l a b l e  
3 5 '  
2 5 '  
4 9 1  s q .  f t .  
a l l  N o  
n a t i v e  t o  P o r t l a n d  m e t r o p o l i t a n  r e g i o n  
p e s t  a n d  d i s e a s e  r e s i s t a n t ,  s u b s t i t u t e  f o r  
4 0 '  3 0 '  7 0 7  s o .  f t .  a l l  N o  
A m e r i c a n  E l m  
Street Tree List - Large Stature Trees 
over 40' in hei ht at maturi 
.. 
Red Maple Acermbm1JJ 50' 40' 1256 sq. ft. any No many large stature varietie~ available 
I I ackbercy Celtis occirlmtalis 45' 35' 962 sq. ft. any No tolerant of urban Hre~~es, deep rooted 
E~trQpf:~n Bf:~:~:;h Fagus !)'ltmtim 50' 40' 1256 sq. ft. well drained No beauti ful bark 
White ,\sh F mxi111ts ametictllta 60' 45' 1590 sq. ft. any No plant ~eedles~ varieties 
Qr!:gQ!l b.~b Fraxi1111s latifolia 60' 30' 707 sq. ft. any No native to Pordand metropolitan region 
Green Ash Fraxi1111s petllt!)dtJallim 50' 40' 1256 sq. ft. any No plant seedless varieties 
~ many large stature varieties available, plant males 
~ Maid!::nhait Tm:: Gi11kgo biloba 60' 45' 1590 sq. ft. any No only ~ I lQn!:~lQ!;Y~t Glerlitsin trinm11thos tJar. inem;is 45' 35' 962 sq. ft. No thornle~s, tolerant of urban stresses any 
~ Kentuck~ C:Qffcetree Gym11odarlus rlioims 65' 50' 1963 sq. ft. No fragrant flowers 
" 
any 3. 
c Tulip Tree Litiorlellriroll tulipifera 60' 30' 707 sq. ft. any No beautiful fall color 
a-
" :l 
o· ~QlJth!:rn N~gnolia Mag11olia gm11rliflora 70' 60' 1963 sq. ft. any No broadlea f evergreen, large fragrant white flowers 
8 Blackgym N_]ISSa !JIItJa/im 45' 25' 491 sq. ft. any No beautiful fall color q 
...., LQnQQ!l Planetree Plata/IllS x acerifolia 'Bloodgood' 50' 40' 1256 sq. ft. any N o disease resistant, pollution tolerant 
n 
0 Scotch Pine Pi1111s sylvestris 50' 40' 1256 sq. ft. any No evergreen conifer, striking orange bark 0.. 
" ;;:J Qtf:!'Q!l Whit!: Qak Qmrms gat7)'a!la 65' 50' 1963 sq. ft. any No native to Pordand metropolitan region 
a. WillQwOak Qmmts phellos 60' 45' 1590 sq. ft. any No tolerant of urban strcs~cs 
i3 
~ &d....Qak Quercus mbra 60' 45' 1590 sq. ft. any No beautiful fall color 
< ,:\m!:ti~;an l~ind!:!l Tilia ametica11a 60' 30' 707 sq. ft. any No tolerant of urban strcs~es 0 St~:rling SilY:!:t Lind!:n Tilia tome11tosa 'Sterling Silver' 45' 30' 707 sq. ft. any No dark green leaves with ~ ilver under~ ide~ c 
3 ZclkQva Zelkot;a se" ata 65' 50' 1963 s . ft. No attractive shade tree 
" 
< 
c-
-a 

Bigleaf Maple At"er macmpby/lum 65' 50' 1963 sq. ft. any No native to Portland metropolitan region 
Red Maple A cer mbmm 50' 40' 1256 sq. ft. any No brilliant red fall color 
European Be!:s;h Fagus .rylvatica 50' 40' 1256 sq. ft. well drained No beautiful bark 
White Ash Fra:xi111ts ametit"atta 60' 45' 1590 sq. ft. any No plant seedless varieties 
Green Ash Frax i1111s pmn.rylva11ica 50' 40' 1256 sq. ft. any No plant seedless varieties 
...._ many large stature varieties available, plant 
~· Maidenhal! Tree Gi11kgo bi!oba 60' 45' 1590 sq. ft. any No males only ~ 
Kentucey Coffeetree Gym11ocladus dioic11s 65' 50' 1963 sq. ft. any No fragrant flowers 
13 
a.. broadleaf evergreen, large fragrant white 
c Southern Maiffiolia J\1ag11olia gra11dif7ora 70' 60' 2826 sq. ft. any No flowers a-
" Austrian Pin!: Pi1111s 11igra 55' 40' 1256 sq. ft. No evergreen conifer ::l any 
ci" Eastern White Pine Pi1111s sttvbus 70' 40' 1256 sq. ft. any No evergreen conifer ~ q Scotch Pine Pi1111s .rylvestns 50' 40' 1256 sq. ft . any No evergreen conifer, striking orange bark 
' <: 
n 
0 
a. 
" London Planetree PlalaiiiiS x amifo/ia 'Bloodgood' 50' 40' 1256 sq. ft. any No disease resistant, pollution tolerant ,.., 
~ · Qregon \'{!hit!: Qak Q uerms garryana 65' 50' 1963 sq. ft. any 0 native to Portland metropolitan region 
0 Willow Qak Querms pbel/os 60' 45' 1590 sq. ft. any No tolerant of urban stresses ~ 
< 
Red Oak Q11ercus mbra 60' 45' 1590 sq. ft. any No beautiful fall color 
2.. graceful vase shaped tree, disease resistant c: 
3 Accolade Elm Ulmus 'Morton' 70' 60' 2826 sq. ft. No substitute for American elm <> any 
--:: Lacebark Elm Ulmus parvifo/ia 60' 50' 1963 sq. ft. any 0 interesting mottled bark 
::; rounded spreading crown, disease resistant 
Pioneer Elm Ulmus 'Pioneer' 50' 50' 1963 sq. ft . any No substitute for American elm 
Or!:gon M~rtl!: Umbellulana t-alijomica 70' 50' 1963 sq. ft. any No broadleaf evergreen 
Zelkova Zelk ova serrata 65' 50' 1963 s . ft. No attractive shade tree 
> 
'"0 
'"0 
(!> 
::;l 
~ 
v.> 

L\rmstrong Maple A t'lir mbmm 'Armstrong' 45' 15' 177 sq. ft. any No orange-red fall color 
Bowhall Maple A cer mbmm 'Bow hall' 40' 15' 177 sq. ft. any No b right red fall color 
T'rans Fontaine 
!Torn beam Carpi1111s betulus 'Frans Fontaine' 35' 1 5' 177 sq. ft. any No narrowes t o f the Cmpi1111s b. cultivars 
Dawyck Purple Beech Fag11s SJ'ftJatica 'Dawyck Purple' 40' 12' 113 sq. ft. any No purple leaves fo r entire growing season 
Princeton Sentry (~inkgo Gi11kgo biloba 'Princeton Sentry' 40' 15' 177 sq. ft. any No seedless, bright yellow fall color 
,..., ,\rnold Tulip Tree Uriodmdro11 tulipifera 'Arnold' 40' 10' 79 sq. ft. any No fa st grower 
~-
!?., 
Edith Bogye Magpo.lia Mag11olia gra11dif/ora 'Edith Bogue' 30' 15' 177 sq. ft. No b roadleaf evergreen 
r? any (~alaxy Magnolia Mag11olia x 'Galaxy I 30' 15' 177 sq. ft. any No showy pink fl owers a. 
c Tschonoskii Crabapple Malus tscbo11osk ii 30' 1 5' 177 sq. ft. any No good fall color 
a-
" 1\rnold Sentincl ,\ustrian :l 
6' Pine Pi1111s 11igra 'Arnold Sentinel ' 35' 10' 79 sq. ft. any No evergreen coni fer 
2 Fastigiate White Pine Pi1111s strob11s 'Fas tigiata' 30' 10' 79 sq. ft. well drained No evergreen conifer R 
'< Quaking ,\spen Populus trellluloides 30' 1 5' 177 sq. ft. No native to the Portland Metro region n any 
0 ----
0.. Capital Pear Py ms callerya11a 'Capital' 35' 12' 113 sq. ft. any No glossy summer foliage 
" ;;::; Chanticleer Pear JYms caller)'alla 'Chanticleer' 40' 15' 177 sq. ft. No resistant to ftreblight 
" 
any 
d. · 
6 
~ Columnar Sargent Cherry Pmmts sar;ge11tii 'Columnaris' 35' 1 5' 177 sq. ft. any No pink flowers and reddish bark 
< Skyrocket Oak Q uercus robar 'Fas tigiata' 45' 1 5' 177 sq. ft. well drained No may hold b rown leaves into winter 0 
c Q uercus robur x Q. alba 3 
" 
< Crimson Spire Oak 'Crimschmidt' 45' 15' 177 sq. ft. well drained l 0 red fa ll color 
_, (~iant .\rborvitae evergreen conifer, species native to the 
"' "Virescens It Tbuja plica/a 'Virescens' 25' 12' 113 sq. ft. moist No Pordand Metro Region 
Corinthian Linden Ti!ia cordata 'Corzam' 45' 1 5' 177 sq. ft . any No narrowes t o f the linden cultivars 
Columnar Zelkova Zelk ova serrata 'Musashino" 45' 15' 177 s . ft. No fine textured leaves 
> 
'"0 
'"0 
(1) 
::l 
~ 
-l>-

Native Trees 
.. 
Grand Fir Abies grandis 150' 40' 1256 sq. ft. Large No Wetland, Riparian, Upland 
Big-leaf ;-.,[a!]lc Acer lllatTopi!JIIum 65' 50' 1963 sq. ft. Large No Upland 
Red Alder Alnus mbra 100' 40' 1256 sq. ft. Large No Riparian, Upland 
l\1adrone A rb!lt!ls 1mnzjesii 40' 30' 707 sq. ft . Medium No Upland 
Pacific Do~ood Comus llllttallii 40' 30' 707 sq. ft. Medium No Upland 
Black IT awthorn Crataegus douglasii 25' 20' 314 sq. ft. Small Yes Wetland, Riparian, Upland 
n 
.~ Oregon ,\sh Fraxinus latifolia 60' 30' 707 sq. ft. Large No \V'etland, Riparian 
c Ponderosa Pine Pi1111s ponderosa 200' 30' 707 sq. ft. Large No Upland ..., 
-: 
:@ 
a. Black Cottonwood Pop11!11s balsamifera ssp. llichocarpa 175' 40' 1256 sq. ft. Large No Wetland, Riparian c 
a- Quaking .\s12en Populus tremuloides 30' 15' 177 sq. ft. Medium No Wetland, Riparian 
" 
" Bitter Chercy Pm1111S emarginata 30' ;s: 20' 314 sq. ft. Medium No Riparian, Upland 
(l Douglas Fir Pswdots11ga IIJCII~esii 180' 40' 1256 sq. ft. Large No Upland ~~ Oregon White Oak Q11erms ganyana 65' 50' 1963 sq. ft. Large No Upland 
n 
c Cascara RJJa/11/IIIS pursbiana 35' 25' 491 sq. ft. Medium No Riparian, Upland 0.. 
" ;N 
" 
Pacific Willow Salix Iucida ssp. lasiandra 40' 30' 707 sq. ft. Medium No Wetland, Riparian 
d· Rigid Willow Salix rigida /Jar. !llacrogemJila 30' 20' 314 sq. ft. Small No Wetland, Riparian 0 
~ Scouler Willow Salix scoHieriana 40' 40' 1256 sq. ft. Medium No Wetland, Riparian, Upland 
< Pacific Yew Tax us bre/Jifolia 40' 30' 707 sq. ft. Medium No Riparian, Upland c ----
c Western Red Cedar T b1!)a plimta 100' 30' 707 sq. ft. Large No Wetland, Riparian, Upland 3 
" \X' estern I !em lock 150' 40' 1256 s . ft. No 
< 
_, 
Ln 

< 0 
c 
3 
r: 
N oi'va~ maple 
Srcamore maple 
Tree-of-heaven 
European white birch 
English hawthorn 
English holly 
Princess tree 
\X'hite poplar 
Sweet cherry 
Black locust 
European mountain ash 
Siberian elm 
Nuisance Tree List 
Acer platanoides leaf detail fruit detail flower detail 
Acer pseudoplatanus leaf detail fruit detail flower detail 
Ailanthus altissima leaf detail fruit detail flower detail 
Betula pendula leaf detail fruit detail flower detail 
Crataegus mono~na leaf detail fruit detail flower detail 
Ilex aquijolium leaf detail fruit detail flower detail 
Paulownia tomentosa leaf detail fruit detail flower detail 
Populus alba leaf detail fruit detail flower detail 
Prunus avium leaf detail fruit detail flower detail 
Robinia pseudoacada leaf detail fruit detail flower detail 
S orbus aucuparia leaf detail fruit detail flower detail 
Ulmus umila leaf detail fruit detail flower detail 

EVISIONS: 
\ 
__/ -
IMIATS: I 
I 
I 
I 
I 
L 
r 
I 
J_ ! ~r o~ '--]- ~-.-~-.~-w-,--
~-~~ \·r j 1 Ll,., ~ 
--- ~ - · . I I 
_ ••. · ::..-.-.. ~-, ...... 1 , . ~ I I !lf I I I I riRRtGAOOH suM (TYP) I ' I ' I £1 t t ·~ X \ ==y- ,....., . 
GfNfiW NOJFS· 
1. All POROOHS or LOTS 1 AND 2 NOT OCCIJ'1ED BY BU1lDIHCS OR PAVING TO BE lNIOSCAPE AND llRIGATED. 
2. All NOH-NATIVE VEG£TAOOH WITHI< THE 50' SfREAij BUrrER IN TRACT A TO BE REWOVED AND REPLICED W!TH NATIVE 
VEG£TAOOH ANO TEWPORARY llRIGAOOH rOR A PERIOD or ONE YEAR OR UHTll P\.AIITS .IRE ESTABIJSHED. 
ROOT PROJ[crpN lONE NO!£S· 
EJ«::!!ACHWEHT INTO THE ROOT PROTECOOH ZONE IS AllOWED W!TH PllO.{CT ARBORIST APPfKJI.Il AS DESCRilED IN THE 
rOll.DWINC NOTES: 
1. EXCAVAOOH ~ THE TOP 24" or THE SOL IN THE CJm:AI. ROOT ZONE AAf). SHOUlD BEGIN AT THE EXCAVATION UNE THAT 
IS CLOSEST TO THE IR[[. 
2. THE EXCAVATION SHOUlD BE llON[ BY HAHO~ OR W!TH A BACKHOE AND A 11/.H W!TH A SHOVEL PRUNING SHEARS. 
AND A PRUNII«: SAW. 
3. 1r DONE BY HAND, All ROOTS 1• OR LARGER SHOUlD BY PRUNED AT THE EXCAVAOOH UNE. 
4. 1r DONE W!TH A BACKifJE (WOST UKEl.Y SCEHARK>). THEN THE OPERATOR SIWl START THE CUT AT THE EXCAVATION UNE 
AND CARErULLY TID." roR ROOTS/~AHCE. WHEH THERE IS ~AHCE, THE 11/.H W!TH THE SHOVEL HANO DIGS 
IIWND THE ROOTS ANO PRUNES THE ROOTS LARGER THAN 1• OIAWETER. 
TA> LOT 600 
TA' MAP 2S I 048D 
/ 
x ..... ...-;;--
. .: 
/ 
/ 
-~ { \_PROPOSED STORW 
~ 
I 
: I 
T,~, LrJT 800 
lA· I.W· 2S I 048[ 
"")t 
rr- \ t I 
I 
TA' LOT 700 
TA! MAP 25 I 04BD 
ANOUI POSlS eT II: 
INSTAUID10AIIP1HCJ" 
NOU5S1HAN1/3'H 
TOlAI.IOiKT (F POST 
"""' 1. IIDA.. rna: FOR TJII PRmCTDI rou, OII.Y. 
TREE PROTECTION NOTES: 
A. NO CIW«B SIWl 8£ II.ODE TO NIY ASPECT or Tl£ API'ROI'ED lll8AH rORESTRY PlNI WI1NOUT WRfT1UI CONSOli FRQij THE PROJECT ARBORIST ANO CITY NlOORIST. 
B. TIIEI.Jj[ rQR CIDR1NC. GRADING. AND HSTAUAOOH or TREE PROTECOOH W£J.SIR5; WOftK Will BEGIN WITHIN Tlfl[[ (J) W[[J(S or Pf1 P[RjjiT INSURAia BY THE CITY. lR[[ 
PROTECOOH WU 8£ INSTAU.ED PRKlR TO NIY GROOND DISI\IRIIANCE WORK. !:WRIN;, AND GR.IIlNG Will rDLLOW. 
C. PlJCINC III.TERW.S NOR lRUS. NO PERSON III.Y COIIlUCT NIY .ICTMTY W1THN Tl£ PROTECTED AAfA or NIY IR[[ OCSIGNATED TO REMAIN. INCliJDII,C, BUT NOT UWITED TO. PARKNC 
EOUIPWOO. PLICING SOlltliTS. STORHG 8I..UIIIG III.TERW. ANO SOIL OCPOSITS. IXJIIPNC CONCR£TE WASNOUI AND LDCATNC BURN lfJLES. 
D. AITACHWENTS TO TRt:ES DUliNG CDNSTRUCOON - NO PERSON SIWl AITACH N1Y OMCT TO N1Y IR[[ DESIGNATED rOR PRESERVAIDN. 
E. PROTECTM BAR~ER. PIOOR TO NIY GROUND OISTURBAHC[ BY Tl£ CONIRACTOR: 
1. SIWl ERECT AND WAIITAIN READILY VISa£ lR[[ PROTECOOH fiNCIHG .ILDNG Tl£ OUTER EDGE AND CDWPlfTELY ~DING THE PROTECTED AAfA or All PROTECTED TREES OR 
GROUPS or TREES AS SHOWN. fU«:[S SIWl BE CONSTRUCTED or S rOOT TAU 1£1Al. SECURID TO EIGHT rooT TAU 1£1.11. POSTS. POSTS SIW..l NOT 8£ PUaD FURTHER THAN 
8 rm O.C. APART. 
2. III.Y 8£ REOURED TO !XMR W!TH loMCH TO A DEPTH or AT LfAST SIX (6) 110£5. OR W!TH P\.YOOOD OR ~WILAR 11/.TERIAI.. OVER THE ROOT ZONE or A TREE ~ ORDER TO 
PROTECT ROOTS FRQij Ollila CAUSED BY HEAVY ECMPIIEJIT. 
J. SIWl PROHIBIT EXCAVAOOH OR Cot.IP~ or EARTH OR OTHER POTENTIIU.Y DAiolloGING ACTMTES W!THI< THE IR[[ PROTECTlON ZONE. 
4. III.Y BE REOORED TO W~IW~E ROOT Ollila BY EXCAVAOOH or A TMl (2) fiD IUP TRENCH, AT THE EDGE Or Tl£ IR[[ PROTECOOH ZON~ TO CIIAN.Y SEVER Tl£ ROOTS or 
TRt:ES TO 8£ RETAINED. 
5. 11/.Y 8£ REOORED TO HAVE CORRECTM PRUNING PERfORIIED ON PRESEJMD TREES IN ORDER TO AVOIO IWoiAG[ FRQij 11/.CH~ OR BUI.DII«: ACTMTY. 11/.Y 8£ REQUREIJ TO 
WAIITAIN TREES THROUGHOUT COHSTRlJCOOH PERIOD BY WATER!~«: AND FIRilJZHG. 
6. SIWl WAINTAIN THE IR[[ PROTECTlOH fiNCIHG IH PLICE UHTL THE POO..{CT ARBORIST AND CITY AR80RIST AU!l()RIZES THEIR REII<NAL. 
7. SIW..l ENSURE THAT NIY LNIIlSCAI'IhC DOH[ ~ Tl£ TREE PROTECOOH ZONE SUIISEOOEJIT TO THE REII<N.Il or THE BIRRIERS SIW..l 8£ ACCOWPUSf£D W!TH LJGHT WoiCHHERY OR 
HAND LABOR. USE PI.AHT III.TERI.ILS W!TH Cot.IPATlBlE WATER RECIJREIIENTS TO TREE TO BE PRESERVED AND DIRECT SPRAY llRIGATION AWAY FRQij TR\JHKS. 
r. THE GRADE SIWl NOT BE ELEVATED OR REDUCED WITHIN THE TREE PROTECOOH ZONE WITHOUT THf PROJECT AROORIST'S AIJTHORIZATION. THE POO..{CT ARBORIST 11/.Y AllOW COVERAGE 
or UP TO ONE HALr or THE AAfA or THE lR[['S ROOT ZONE W!TH LJGHT SOLS (NO CLAY) TO THE W~IWUW DEPTH NECESSARY TO CARRY OUT GRAOt«; OR lANOSCIPIHG PL1HS. F IT 
Will NOT III'ERI. THE SURVIV.Il or THE TRt:E. AI:RAOOH OCVCES 11/.Y BE REQUREIJ TO EHSURE THE IR[['S SURVIVAL. 
C. IF THE GRADE ADJIWIT TO A PRESEJMD TREE IS RAISED SUCH THAT IT COULD StOUGH OR ERODE NTO THE TREE PROTECTION ZONE. IT SIW..l BE PERIIAHEHTI.Y STABIUZED TO 
PREVENT StlrroCAOOH or Tl£ ROOTS. 
H. AN llf'ElMOUS SLRrACE SHAll NOT BE IHSTAU.ED WITHN THE TREE PROTECOOH ZONE or NN TREE TO 8£ PRESERVED WI1NOUT THE AUTHORIZATION or Tl£ POO..{CT ARBORIST. THE 
PROJECT ARBORIST III.Y REQIARE SPECiflC COHSTRlJCOOH IIETHOOS AND/OR USE or AI:RAOOH OCVCES TO ENSUlE THE IR[['S SURVIV.Il AND TO Wr<IIIIZE THE POTEJITlll. rOR ROOT 
INDUCED IWoiAG[ TO THf IWPEJMlliS StM ACE. 
TO THE GREATEST EXTENT PRACTICAL. IITIUIY TRt:HCIB SIWl BE LOCATED ~ Of THE TREE PROTECOOH ZONE or TREES TO BE PRESERVED. THE PROJECT AR!IORIST III.Y REOORE 
THAT liTIUT1ES BE TUNNELED UNDER THE ROOTS Or TREES TO BE PRESEJMD F Tl£ PROJECT AR80RIST DETERIIII£S THAT IRt:t«;HIHC WOULD SICNIFCAHTI.Y REDUCE THE CHAHCE5 or 
THE TREES SURVIVAL. 
J. DllECOOH.Il rElliHC. DIRECOOH.Il rElliHC or TREES SIW..l BE USED TO AVOO Oollila TO TREES OCSIGNATED rOR PRESERVATION. 
K. AOOITlOHAI. REOOREWENTS. THE PllO.{CT AR80RIST III.Y REOORE AIIOIOONoll. TREE PRESERVAOOH WEASlJlES WHICH .IRE CDHSISTDIT W!TH TREE CARE NJUSTT!I' STAHIW!OS. 
SCALE ! " = 20 FEET 
----
~ ~~ ~ 
SCALE SHOWN IS FOR FULL 
SIZE SHEET ( 24.X361 ONLY 
,, . ..,..,... 
FtACaNC: ATIAOO TO TIPS 
CI-POSlS 
t' SOJIIIE, I CAUGE IOAI.VNCZED 
..,..,., 
l..EOEN) 
EXISTN; TREE TO BE ROI(M[) 
EJOSTll(; lR[[ DRIPlJI£ 
EXISTN; TREE CAHOI'f .IREA 
CANOPY .IREA 
TREE I'ROT[C!Qj rEt«;£ 
EXISTHG SNffARY 
PROPOSED SNliARY 
EXISTNC WATER 
PROPOSED WATER 
PROPOSED WATER ICIER 
EXISTHG WATER ICIER 
EXISTING STORII 
PROPOSED STORII 
EXISTN; GAS 
PROPOSED CAS 
EXISTING ELECTRIC 
PROPOSED ELECTRIC 
PROPOSED IRRIGATION 
X 
~ 
fZZJ 
CJ 
I 
I, JOHN ARBORIST, ATTEST THAT 
THIS TREE CANOPY SITE PLAN 
MEETS ALL or THE 
2. ID.JCWIIS rE PSIDJ(CIDt N1lA Ill II: (SJ.I8BG N ll(: m.D B'l' 11£ NIDIST 
EXAMPLE TREE 
PRESERVATION AND 
REMOVAL SITE PLAN 
REQUIREMENTS IN SECTION 10, 
PART 2, or THE CITY or TIGARD 
URBAN fORESTRY MANUAL. 
JOHN ARBORIST, CERTIFiED Pt!~= 
"""""'-J. IIIJUr(WII30fPim[ClDflllf).SifJW)II[SJAI((IINr(l1lJGCilll!JI'Tt£N!E!(R51' 
PRO! 10 NSrlt1.IC m.w:n. 
4. NIIJIJ DMIIa TO CIIIJI:R. lb1r ZONL lXI NJT IWWOE OR SMR lNa: fiDOTS ItO 
061AUJICPOSI>. 
5. [(w::f: St«JltD liE I6IIWIIIIl nR:llODJ1 rot6TR.CTDI. 
METAL Tie PAOTECllON FENCE 
TREE PRESERVATION/REMOVAL PlAN BY JOHN AROORIST, 
CERTifiED ARBORIST #PN-0000, WITH MJt;; COUABORATM. 
APPROXIIATE SfREAij BED LOCAOOH 
WETI.ANO 
SICNiflCNIT IMIAT BOlllllARY 
~ 
~ 
L....::....J 
•ATE: 07-11-20TT 
:':~r:,i"':~J~~/'s,m' ~ABc !21[l!II!.Jli ___ ~~:~:J =--~~;,;:;----------J TIGARIJ. OREGO\ 9722:1 PFEPAREO FOR: .Qfl St.lllH EVERGREEN HEIGHTS PARTITION I Pll : (503 / 555- XXX\ PO BOX 111 1'-'X (50:\J 115 ~dX'H TJCARD, CREGCW 97223 "'"" """""-''" '"""'" r "" COLLABORATIVE PH: SOJ-909-5555 
rAX: SOJ-909-5556 
LJCE.\S£0 I\' OR, 'll. & Ill or.~ 1n1or • .UOI ~ I tn lltE • M...'-· .... rv. • l'-' IN' ~M' AIOIIT::C1 1"11E TIGARD 
TAXI.OT 1700 
OREGON 
TAXIIAP 2 4E 25 ~o:-; 
190 SW 147TH ST. 
City of Tigard Urban l:orcstry Code Rc,·isions I \'olumc I\' I 79 
JOB NU~BER 
2001 
SHEET 
APPENDIX 7 
!REVISIONS: 
:J 
\ 
SIGNFI:NIT __/' ' 
HoiBITAT 80UIIW!Y I 
I 
I 
I 
I 
l 
I 
I 
I 
I 
) \ ,,,_ 
--------
EXAMPLE 
TREE CANOPY 
SITE PLAN 
1 
5,705 Sf 
5' SIOEYNID saa.c~<-/ 
J_ /rn Oo;:J 
--- ~ I I --~ - - :1 
EN LANE - - --. . ·~-r~ ~ -=..JU _,J-:::l -=-IIl _ ..,_ ~ -T ---- ---::.-..lU - - - - _ - -
,.J i -~'" 
TA:· LOT 600 
lA> MAP 25 1 0480 
~ -- Tel 'T~" I L.,_ 
I ; 
I r -~ I 
I 
" I ~ II 
.j_ EOOH BOGUE WoGI«>UA 
I I I I I I TAx l OT 800 
3 rll ' I lA> MAP [ 1 0480 I - !r ---= 
~~j J - i 
l:::tl ~-~  I 001 
I ROOT BARRIER 
TA1 LCT 700 
TA.I MAP 2S I 0480 
OFFJfE LOfATEn Al : ~~ 
IOOOISfSI HEEI. SI I'IEI /"'A· T""'> ........... BC,.., ,_~~~--- KRJ BOT TJGARO. ORECI'!~ 9722:! 
PU: (503) 555--XAXX 
FAX: (503) 555-XX'C< 
f:IIAIL ' "~'""'llf_fOIIAilhRATII E [ (01 COLLABORATIVE 
llfF\"SEIJ I\ r)R. WA. l Ill 
KRJ 
PREPARED FOR: .ntl SIIITH 
PO BOX 111 
TlGARD, ()R[GOI 97223 
PH: 503-909-5555 
ffo:J; 503-909-5556 
City of Tigard Urban Forestry Code Rc,-isions / \'olumc I\' I 81 
PLANT LEGEND 
STilEET mEES 
SYIIBOL CTES. BOT.<NICAl NAil: 
0 
0 
1()1[, 
ACER RWRUW 'AAWSJRONG' 
WoGI«>UA GRANJiflDRA 'EDITH 8QG(,{' 
CXliiiiON NAWE 
ARWSTRONG RED IW'U 
EOOH BOGUE IW:I«<UA 
SIZE CONim)N SPACt«; 
2" CIL ~ AS SHIJWl< 
2"CIL ~ AS SHIJWl< 
1. PlNirER STRP AAEAS ALOOG MRGR!:EN LN£ AHO SW 147TH JRF. JRF.AS or POTDITIAL SOL COIIPACOON, LUrNG 1R[[ CROWTil F SOL CXlUPACT10N 
OCCURS, B.ICKt«JE IURNNG 5/KMD BE U5EO TO lOOSEN SOL 
2. B.ICKtfJE TURNING' REIIO'IE IHf lAYERS or COOO TOPSOL SP1£AO J" -4" or ORGIMCS (HGH-LCNN COIIf'05T) OR E5CS (EXPAHOEO SHAII/CALCN: 
CLAY) AIENOWENT OVER THE .1R£A PRlOR TO IURNNG THE SOIL IWNTHNI.c A SArE DISTAl«:[ rR011 PAVING, SIOEWALKS_ .<NO S1ROCTURES, USE BACKt«JE 
TO TURN SOil TO 36" DEPTH. BREAK SOil MD lARGI: PEDS AHO lOOSElY INCORPORATE 11£ SOL AIIEHOIIENT. IWNTAI< A SlCI'E or COIIPACTED SOl AT 
11£ EDGE or or PAVING SO AS NOT TO IJID[RII~E THE PAWIG SUB-BASE. HANJ - 114Y BE hlCESSAI!Y ALONG 11£ EDC£5 or PAVING IJ() AT 
WAllS, 00 NOT T1U TO A DEPTH GREATER THAN 11£ BOTTOW or fOOTING- N1ER M!K, R£ -SPRfAD TOPSOl IJ() 100 J" -5" Of YNID WASTE 0RGAH1C 
AIENlWENT OVER THE SURfACE .<NO UGHTLY 1ll TO BREAK 11£ SOL MO TEXlUR[ SlKTAilf TO rN: GRADE. 
SCALE t " = 20 FEET 
---~ .!""!. ~ ~ 
SCALE SHOWN IS FOR FUll 
SIZE SHEET ( 24MX36i ONLY 
L.EGENJ 
EX5TlNC 1R[[ ORI'lJ£ 
PlNITED 1R[[ 1141UR[ ORI'lJ£ 
EXISTINC 1R[[ CNa'r JRf.A 
CANOPY JRf.A 
1R[[ PRUI[CTI)H rna: 
EX5TlNC SAIITNrf 
PROP05[I) SAIITNrf 
EXISTINC WATER 
PROP05[I) WATER 
PROP05[I) WATER W£TER 
EX5TlNC WATER I£T[R 
EXISTINC STORII 
PROP05[I) STORW 
EX5TlNC GAS 
PROP05[I) GAS 
EX5TlNC EllC!RIC 
PROPOS[() EllC!RIC 
PROPOS[() llR1CAT10N 
N'm>XIIATE SIREAII liD lOOOI)H 
W£1lNI) 
SIGN!FrNITH!IITAT~ 
~ 
CZZl 
CJ 
I 
0 
~ 
~ 
l:____::_j 
I, JOHN ARBORIST, ATIEST THAT 
THIS TREE CANOPY SITE PLAN 
MEETS All OF THE 
REQUIREMENTS IN SECTION 10, 
PART 2, OF THE CITY OF TIGARD 
URBAN FORESTRY MANUAL 
JOHN ARBORiST, CERTIFIED ARBORIST 
PNN-0000 
'Atr: 07-11-2011 
~ ~ 
JOB NUMBER 
2001 EVERGREEN HEIGHTS PARTITION 
190 SW 147TH ST. 
TIGARD OREGON 
c:snRD 
NBliET 
~::::::::r 
SHEET 
APPENDIX 8 
TAXLOT 1700 TAXIIAP 2 4£ 25 
U rban Forestry Plan - Supplemental Report Example Template 
General Information 
Date: 
Project Name: 
Project Arborist or Landscape Architect Name: 
Project Arborist or Landscape Architect Address: 
Project Arborist or Landscape Architect Telephone Number: 
Project Arborist or Landscape Architect Email Address: 
ISA Certified Arborist No. : 
ISA Certified Tree Risk Assessor No.: 
Landscape Architect Stamp: 
Project Summaty 
Specifications 
Tree Protection Fencing Specifications: 
Tree Preservation Specifications: 
Stand Preservation Specifications: 
Soil Characteristics and Specifications for Improvement: 
Tree Planting Specifications: 
Stand Planting Specifications: 
Appendix 9 
City o f Tigard Urban Forestry Code Rc,·isions I Volume IV I 83 
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Urban Forestry Plan -Supplemental Report Example Template 
Planted Tree Inventory 
Tree# Genus sp./ Caliper (Decid.) or Mature Canopy Mature Canopy Available Comments 
Common Height (Evergreen) Spread (ft) Area (ft2) Soil Volume (ft3) 
Planted Stand Inventory 
Stand# Genus sp./Common 1 Hgt. or Container size No. ofTrees Avg. Spacing (ft) Total Mature Comments 
Genus sp./Common 2 Hgt. or Container size No. ofTrees Avg. Spacing (ft) Canopy Area (ft2) 
< 
Genus sp./ Common 3 Hgt. or Container size No. ofTrees Avg. Spacing (ft) Delineated at the 
Genus sp./Common 4 Hgt. or Container size No. ofTrees Avg. Spacing (ft) Outer Edge of 
Genus sp./ Common 5 Hgt. or Container size No. ofTrees Avg. Spacing (ft) the Stand 
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2 x  C a n o p y  
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M a t u r e  1 . 2 5 x  M a t u r e  
T o t a l  C a n o p y  E f f e c t i v e %  
T r a c t #  
A r e a  ( f t 2)  A r e a  ( f t 2)  o f  
A r e a  ( f t
2
)  o f  C a n o p y  
C a n o p y  C a n o p y  
A r e a  ( f t 2)  p e r  
C a n o p y  
( e x c l u d e  
P r e s e r v e d  P r e s e r v e d  
A r e a  ( f t
2
)  o f  
A r e a  ( f t 2)  o f  A r e a  ( f t 2)  o f  
l o t  o r  t r a c t  
( C a n o p y  A r e a  
s t r e e t s )  
T r e e s  S t a n d s  N a t i v e  
N o n - N a t i v e  P l a n t e d  
( w  I  c o n d .  a n d  ( w  I  c o n d .  a n d  
P l a n t e d  P l a n t e d  S t a n d s  
L o t  o r  T r a c t  
pres.~2) pres.~2) 
T r e e s  T r e e s  
A r e a )  
T o t a l  
* N o t e :  e f f e c t i v e  t r e e  c a n o p y  c o v e r  i s  r e q u i r e d  t o  b e  c a l c u l a t e d  o n  a  l o t / t r a c t  b y  l o t / t r a c t  b a s i s  o n l y  i n  t h e  R - 1 ,  R - 2 ,  R - 3 . 5 ,  R - 4 . 5  a n d  R - 7  d 1 s t r 1 c t s .  
>  
' " 0  
' " 0  
( C  
: : : ;  
0 . .  
. . . . . .  
> <  
' V  
T h e  s t a n d a r d  p e r c e n t a g e  o f  e f f e c t i v e  t r e e  c a n o p y  c o v e r  f o r  e a c h  l o t  o r  t r a c t  i n  t h e  R - 1 ,  R - 2 ,  R - 3 . 5 ,  R - 4 . 5  a n d  R - 7  d i s t r i c t s  s h a l l  b e  a t  l e a s t  
1 5  p e r c e n t .  
T h e  s t a n d a r d  p e r c e n t a g e  o f  e f f e c t i v e  t r e e  c a n o p y  c o v e r  f o r  t h e  o v e r a l l  d e v e l o p m e n t  s i t e  s h a l l  b e  a t  l e a s t :  
1 .  4 0 %  f o r  R - 1 ,  R - 2 ,  R - 3 . 5 ,  R - 4 . 5  a n d  R - 7 d i s t r i c t s ,  e x c e p t  f o r  s c h o o l s  ( 1 8 . 1 3 0 . 0 5 0 0 ) ) ;  
1 1 .  
i l l .  
3 3 %  f o r  R - 1 2 ,  R - 2 5 ,  R - 4 0 ,  C - N ,  C - C ,  C - G ,  C - P ,  M U E ,  M U E - 1 ,  M U E - 2 ,  M U C ,  M U R  a n d  1 - P  d i s t r i c t s ,  e x c e p t  f o r  s c h o o l s  
( 1 8 . 1 3 0 . 0 5 0 0 ) ) ;  a n d  
2 5 %  f o r  M U - C B D ,  M U C - 1 ,  1 - L  a n d  1 - H  d i s t r i c t s ,  a n d  f o r  s c h o o l s  ( 1 8 . 1 3 0 . 0 5 0 0 ) )  i n  a l l  d i s t r i c t s .  
Urban Forestry Plan -Supplemental Report Example Template 
Tree Canopy Fee Calculation (if applicable) 
If the percentage of effective tree canopy cover is less than the applicable standard percentage for 
the overall development: 
1. Find the required fe of tree canopy: 
(overall development site area) x (standard required % (40%, 33%, or 25%)). 
2. Find the fe of tree canopy the development is short: 
(required fe of tree canopy from 1 above) - (proposed fe of tree canopy). 
3. Find the $ value of tree canopy: 
(PNW-ISA wholesale median cost for a 3" deciduous tree in the Willamette Valley) --o- 59. 
4. Find the required tree canopy fee: 
(amount of ft2 of tree canopy from 2 above) x (the $ value of tree canopy from 3 above). 
If the overall development meets the applicable standard percentage, but the percentage of effective 
tree canopy cover is less than 15% for any individual lot or tract in the R-1, R-2, R-3.5, R-4.5 and R-
7 districts: 
1. Find the required fe of tree canopy for the deficient lot or tract: 
Oat or tract area) x 15%. 
2. Find the fe of tree canopy the lot or tract is short: 
(required £e of tree canopy from 1 above) - (proposed fe of tree canopy) . 
3. Find the $ value of tree canopy: 
(PNW-ISA wholesale median cost for a 3" deciduous tree in the Willamette Valley) --o- 59. 
4. Find the required tree canopy fee: 
(amount of fe of tree canopy from 2 above) x (the $ value of tree canopy from 3 above). 
Signature of Approval 
I hereby attest that: 
1. The Tree Preservation and Removal site plan meets all o f the requirements in Section 10, 
Part 1 of the Urban Forestry Manual; 
2. The Tree Canopy site plan meets all of the requirements in Section 10, Part 2 of the Urban 
Forestry Manual; and 
3. The Supplemental Report meets all o f the requirements in Section 10, Part 3 of the Urban 
Forestry Manual. 
Appendix 9 
City o f Tigard Urban Fores try Code Rc,·isions I Volume IV I 87 

/ 
"' 
EVISION S: 
I 
l I 
I 
I 1 --+-1 
.~ 
~ I ~OEWAIJ( 
EVERGRE N LANE 
r~ 
1, , 
- P1N1TER S1RI': IR£A Of POTOOW. SOIL 
r- COWPACOON; SIT N01[S 1 ! 2 "MS 
SHEET. 
STREET TREES 
SYIIBOL BOTANICIL NAil[ COIAION NAIIE SIZE C()l()fOON SP.ooNG 
0 .oaR RUIJMj 'ARIISTRONG' AR16TRONG RED WAPI! 2' CN.. B.tB AS SHOWN 
NO~ 
1. PWIJ[R Slll1P NlfJS AlONG EID!GREEN lANE AND SW 14 7TH Ml!. NlfJS Of POTENTIAL SOIL CQWPACTJOH. IJIMTING TREE GROWTH. F SOIL 
COWPJCTJOO ocrulS, SICKHOE TURNING Sl«lU.D BE USED TO LOOSEN SOIL 
2. SICKHOE TURNt<G: RE.I«M: Nrf LAYERS Of GOOD TOPSOIL SPREAD 3'-4' Of ORGANICS (HIGIH.IGHIN COWPOST) OR E5CS (OO'N«D 
SHAlf/CAlCINE ClAY) .t.WENDIIDIT OYER 11£ NlfA. PRIOR TO TURNING THE SOL WAINTIINNG A S.lf[ 01STANCI: fROII PAW«:, SllEWAU<S, 
Nil STRUCTURES. US£ SICKHOE TO TURN SOIL TO 36' DEPTH. llRL'K SOIL INTO lNlGE PEDS NrJ LOOSElY NCOOPORAlE 11£ SOIL 
AIIENOWENT. IIIOOAIN A SUI'£ Of COWPACTED SOIL AT Tl£ EDGE Of Of PA~NG SO AS NOT TO UNDERliNE 11£ PAW«; SUB-BASE. 1W1> 
TURNING WAY BE tt:CBSARY AlONG 11£ EDGES Of PA\1HG AND AT WAllS, DO NOT Til TO A DEPTH GRfATER T1W1 11£ BOTTOM Of 
fOOTlNG. AFTER TUlN1NG. Rt:-SPREAD Tlli'SOI. AND NXJ 3'- 5' Of YARD WASTE ORGANIC AI1Ell)lj[Jif OYER 11£ SURI'.ICE ANil IDfTl.Y Til 
TO llRL'K THE SOIL NTO TDC1l.ll[ SlA'TAIII TO fiNE GI!.IDE. 
~-, 1..-j...,--t....-,-
\ili
' ·1-:--:--:-:1.·.·.·. ~· 
....... '1i. ~-.:.. ..... l i ~ 
~ ·~:~:- ~~·:--:·:-.-;~~~:~ ,--~' 
• • • • • . • • • I • . , t 
.... 0 .... ' . 
. . . . . . . . . . ;..~ ..... l ... : I , r/ 
· · · · lv1 ~ · · · ·1 n 
· ·. ·. · · ·5;ios·s( . ·. 1. ·. I 
................. j ... : I 
"'- ......... ·1· .. j I 
............. ""' ~ • • ~ • I 
OCV fOR RRIGO.TION 
LOT2 
5,056 SF 
f'!lOPOS[() BU1I.IliNG f00ll'R1NT 
I 
I 
I 
I 
I 
I 
,v 
EXAMPLE TREE 
CANOPY SITE PLAN 
FOR SINGLE LOT 
~~ 
3 
8,173 SF " c t_'f.-\SII~G 
_,,, "" 
SCALE 1" - 10 FEET 
----I - 1 ~ C> ....... 5: 
SCALE SHOWN IS FOR FULL 
SIZE SHEET ( 24"X361 ONLY 
~I~" KRJ I~" 9 I OFFICE LOCATEII AT: =r. BOT: IQ .::nu"" IOOOISTSTREET.SI'IT£1 ABC Qt:OOD"' KRJ TIGARO. f)REC.I)N 9722J 
Pll : (503) 555-XXX X 
~~~ ; L~:;~~;,;~~~;~~~LAROilAT I\ f nw COLLABOHATIVE 
liCE.~SED p, t)ft 'lA, I IIJ fM,IUII't" • .ucMITECtt'IE • rL-\~IV. • UHRU'r AIIHIT:'tll.'RI' 
~ SWITH 
PO BOX 111 
TIGARD, ORECOI 97223 
PH: 503-909-5555 
fAX; 503-909-5556 
City of Tigard Urban Forestry Code Rc,·isions I Volume I\' I 89 
L.EGEtf) 
EliSTHG TREE llR1PIJj[ 
PlANT[[) TREE WATlJR[ DR1PlJHE 
EliSTHG TREE CNa't ARt:A 
CNa't IR£A 
TREE PROTECTIJ!I fENCE 
EXlSTIIG SNI!ARY 
PRCf'OS[J) SNI!ARY 
EliSTHG WATER 
PRCf'OS[J) WATER 
PRCf'OS[J) WATER 1lffiR 
EXlSTIIG WATER 11ETER 
EXISTWG Sl(lllj 
PRCf'OS[J) ST(Illj 
EXlSTIIG ~ 
PRCf'OS[J)~ 
EXlSTIIG ELECTTOC 
PRCf'OS[J) fllCTR1C 
PRCf'OS[J) RRIGO.TIOH 
SI>N1f'CNIT IWIITAT BOUNilORY 
~ 
C2ZJ 
CJ 
I 
0 
EVERGREEN HEIGHTS PARTITION 
TIGARD 
190 SW 147TH ST. 
OREGON 
TAXLOT 1700 TAXIIAP 2 4E 25 
'ATE: 07-11-2011 
I 
.o:::== 
JOB NU~BER 
2001 
SHEET 
APPENDIX 10 
I r ROOT BARRIER PER 
I MANUFACTURER'S 
.
1 
r ;1 SPECIFICATIONS 
I lll ' 
1------''---------1% ~ j = l 
@v V/A11 11 ffi UJ UJ 0::: 
t-
LJ._ 
0 
0::: 
UJ 
t-
z 
UJ 
\ -- () 
~ 
0 
0::: 
LJ._ 
(/) 
:J 
0 
<( 
0::: 
0 
l() 
....J 
0 
(/) 
UJ 
....J 
ill 
~II V / Jll -· ... ,, <( ....J <( 
> 
<( 
UJ 
UJ 
0::: 
t-
LJ._ 
0 
OPEN SOIL 0::: 
'·T'--"'\ VOLUME UJ t-z 
UJ 
() 
~ ~ 0 0::: LJ._ 
(/) 
:J 
0 
~I 
0 
l() 
....J 
~ V~l 0 (/) UJ 
....J 
ill 
<( 
....J 
<( 
~ 
', 
J 
;.> 
PLAN 
TOTAL SOIL VOLUME CALCULATION FOR TREE 'A': 
OPEN SOIL VOLUME= 100' x 5' x 3' = 1,500 C.F. 
COVERED SOIL VOLUME= 0 C.F. 
TOTAL SOIL VOLUME= 1,500 C.F. 
1,500 C.F. IS GREATER THAN THE SOIL VOLUME REQUIRED BY A 
STREET TREE IN AN 18' RIGHT OF WAY (800 C.F.) THEREFORE THIS 
SOIL VOLUME MEETS CITY REQUIREMENTS. 
(9 
z 
0 
...J 
::> 
cc 
lL 
0 
lJ.J 
() 
<( 
lL 
~ 
lL 
0 
~ 
I 
(9 
iY 
I 
.. ~~ I /1 J r-SIDEWALK 
I 18' RIGHT OF WAY I 
PROFILE 
TREE 'A' 
.---OPEN SOIL VOLUME 
ROOT BARRIER PER MANUFACTURER'S 
SPECIFICATIONS 
COMPACTEDSUBGRADE 
City of Tigard Urban Forestry Code Rc,·isions I \'olume 1\' I 91 
EXAMPLE SOIL VOLUME 
CALCULATION - STREET TREE 
WITH OPEN SOIL 
NO SCALE 
DWG. NO. 
APPENDIX 11 
w 
u 
<! 
LJ... 
~ 
SIDEWALK 
i---GURB 
ROOT BARRIER PER 
MANUFACTURER'S 
SPECIFICATIONS 
STREET 
I ' II COVERED SOIL I VOLUME 
l II RIGHT OF WAY WIDTH VARIES 
~ I fA 
I ' l I 
~-~j ~Y 
~ 
\ 
PLAN 
(.9 
z 
0 
...J 
:::> 
co 
LJ... 
0 
w () 
<t: 
LJ... 
~ 
LJ... 
0 
~ 
I 
(.9 
0:: 
I 
SIDEWALK I ,, ' ,_Ill' 
COVERED SOIL 
VOLUME PER CITY 
SPECIFICATIONS 
OPEN SOIL VOLUME 
ROOT BARRIER PER MANUFACTURER'S 
SPECIFICATIONS 
4------- DRAINAGE 
I RIGHT OF WAY WIDTH VARIES-----I 
PROFILE 
City of Tiganl Urban Forestry Code Rc,·isions I \'olumc 1\' I HIO 
EXAMPLE COVERED SOIL VOLUME 
PLAN DRAWING - UNDER SIDEWALK 
OPTION FOR STREET TREE 
NO SCALE 
DWG. NO. 
APPENDIX 14 
+ + + + + 
+ + + + t.:URB + + + + + 
I . + + + + 18' RIGHT OF WAY 
ROOT BARRIER PER 
) ... I II MANUFACTURER'S 
DRIVE~AY 
DRIVEWAY 
+ + + + + 
+ + + + 
+ + + + + 
+ + + + 
+ + + + 
+ + + + + 
+ + + + 
+ + + + + 
r-----~+ + + + + 
+ + + + + 
+ + + + + 
SPECIFICATIONS 
COVERED SOIL VOLUME 
UNDER SIDEWALK 
4' X 4' TREE CUTOUT 
(OPEN SOIL VOLUME) 
STREET 
TREE 'A' 
PLAN 
<.9 
z 
0 
...J 
:J 
co 
u.. 
0 
w 
() 
<( 
u.. 
~ 
u.. 
0 
~ 
I 
<.9 
iY 
I 
TOTAL SOIL VOLUME CALCULATION FOR TREE 'A': 
OPEN SOIL VOLUME= 4' x 4' x 3' = 48 C.F. 
COVERED SOIL VOLUME= 28' x 10' x 3' - 48 C.F. = 792 C.F. 
TOTAL SOIL VOLUME= 840 C.F. 
840 C.F. IS GREATER THAN THE SOIL VOLUME REQUIRED BY A 
STREET TREE IN AN 18' RIGHT OF WAY (800 C. F.) THEREFORE THIS 
SOIL VOLUME MEETS CITY REQUIREMENTS. 
18' RIGHT OF WAY 
PROFILE 
TREE 'A' 
OPEN SOIL VOLUME 
4' X 4' TREE CUT OUT 
ROOT BARRIER PER 
MANUFACTURER'S SPECIFICATIONS 
COVERED SOIL VOLUME 
DRAINAGE 
COMPACTEDSUBGRADE 
City of 'l'i),'<l rd Urban Forestry Code Re,·isions I \'olumc I\' I 92 
EXAMPLE SOIL VOLUME 
CALCULATION - STREET TREE 
WITH COVERED SOIL 
NO SCALE 
DWG. NO. 
APPENDIX 11 
I 
I 
I 
I 
I 
I 
\ 
\ 
\ 
\ 
\ 
\ 
\ 
\ 
\ 
\ 
I 
\ 
\ 
BUILDING 
/ 
/ 
/ 
/ 
/ 
/ 
/ 
BUILDING 
\ 
\ 
'\. 
'\. 
'\. 
"' 
"' 
/ 
/ 
"' ....... 
/ 
/ 
/ 
....... 
....... 
1---rL--- l 
- -
PLAN 
OPEN SOIL VOLUME= (PLANTER STRIP AREA+ FRONT YARD AREA CONNECTED BY THE COVERED 
CONTINUOUS ROOT PATH) x SOIL DEPTH 
PLANTER STRIP AREA= 6 FEET X 22 FEET= 132 S. F. 
AREA CONNECTED BY CONTINUOUS ROOT PATH= 4,000 S.F. 
OPEN SOIL VOLUME= (132 S.F + 4000 S.F.) x 3'=12,396 C.F. 
COVERED SOIL VOLUME =(SIDEWALK WIDTH) x (SIDEWALK LENGTH) x (STRUCTURAL SOIL DEPTH) 
COVERED SOIL VOLUME= (6') x (3') x (3') =54 C.F. 
TOTAL SOIL VOLUME=OPEN SOIL VOLUME+ COVERED SOIL VOLUME = 12,396 C.F. +54 C.F.=12,450 C.F. 
12,450 C. F. IS GREATER THAN THE SOIL VOLUME REQUIRED BY A STREET 
TREE IN A 12' RIGHT OF WAY (500 C.F.) THEREFORE THIS SOIL VOLUME MEETS 
\ _ ,_, CITY REQUIREMENTS. 
lY 
(.') 
z 
0 
_J 
i 6'----t-J 
~ 
~ 
u. 
0 
~ 
OPEN SOIL VOLUME 
l/~11 I { TREE 'A' 
STREET 
ROOT BARRIER PER 
MANUFACTURER'S SPECIFICATIONS 
SOIL VOLUME UNAVAILABLE TO 
TREE 'A' WHERE NO COVERED 
SOIL VOLUME ROOT PATH 
::> 
co 
l.L 
0 
lJ.J 
0 
<( 
l.L 
I (.9 
ii: 
I 
! 
SIDEWALK 
I 
ROOT PATH COVERED SOIL VOLUME 
OPEN SOIL VOLUME 
STREET 
ROOT BARRIER PER 
MANUFACTURER'S SPECIFICATIONS 
COMPACTED SUBGRADE 
' 12' RIGHT OF WAY-------' 
URB 
City of Tigard Urban l:orcstry Code Rc,·isions I \'olumc 1\ ' I 93 
PROFILE 
EXAMPLE SOIL VOLUME 
CALCULATION - STREET TREE 
WITH ROOT PATH 
NO SCALE 
DWG. NO. 
APPENDIX 11 
I 
I 
I f.-......_ ~1 -...... 
) 
................ 
< ._ ' ' 'w?.v (PROPERTY LINE) 
... - RIGHT OF "-.._ 
SCALE ! " - 20 FEET 
----~ ..-t ,-n 
SCALE SHOWN IS FOR FULL 
SIZE SHEET ( 24RX36") ONLY 
,,.--- 18' RIGHT OF WAY 
EVISIONS: 
BUILDING FOOTPRINT 
EXAMPLE SOIL 
VOLUME PLAN 
STREET TREE LEGEND 
mooL aTIES. BOTANCII. NA)j[ COWMON fW£ SIZE 
®" AWl RIJ8Mj RED IW'l£ J" CAL 
STREET TREE TABLE 
TREE NUMBER 
001 
002 
003 
004 
005 
006 
007 
OOB 
009 
0010 
0011 
l)fFJIE LUC'ATtn AT: 
\000 JST STRf..t-1. Sl lTE I 
TIGARD. OREGO\ 9722:1 
PI/: (S0.1> 555-XXXX 
F.\X: (50:\! .1.1.1-'nXX 
FJtAll : 1\'FIWABCJ!ll L\BORH I\f . C!>l-1 
II CF.\SF.rJ 1\ OR. 1.\. i IIJ 
SPECIES OPEN SOIL VOLUME 
(C.F) 
RED MAPLE 1,B60 
RED MAPLE 2,637 
RED MAPLE 2,637 
RED MAPLE 2,637 
RED MAPLE 2,037 
RED MAPLE 1,434 
RED MAPLE BBB 
RED MAPLE 639 
RED MAPLE 1,362 
RED MAPLE 2,427 
RED MAPLE 1,B1B 
~ ABc COLLABORAT IVE 
l.._.,I'Uil~t • U'tltl"'lTrtlC • I'LI..\"\JV. • LA..,..<('ort Alt\!llttm.T 
CONOITION SPACINC ~ OPEN SOIL VOLUME 
8&8 ~SHOWN 
[ill COVERED SOIL VOLUME . 
COVERED SOIL VOLUME TOTAL SOIL VOLUME REQUIRED SOIL VOLUME 
(C. F.) (C.F) FOR 1B' RIGHT OF WAY 
NA 1,B60 
NA 2.637 
NA 2.637 
NA 2.637 
507 2,544 
B04 2,23B 
1,62B 2,516 
1,707 2,346 
1,173 2,535 
19B 2,625 
NA 1,B1B 
REMOVAL STORING, AND AMENDED SOILS FOR PLANTER 
AREAS: 
CONTRACTOR SHALL REMOVAL ALL DEBRIS FROM PLANTER 
AREAS AND EXCAVATE TO A DEPTH OF 36INCHES. SLOPE 
SIDES OF EXCAVATIONS AT 1:1 SLOPE OR SHORE EDGES TO 
PREVENT UNDERMINING OF VEHICLE LOAD AREAS AND TO 
PROVIDE A SLOPED PROFILE TRANSITION BElWEEN SOIL TYPES 
AND STRUCTURAL FILL. DISPOSE OF DEBRIS AND SUBSOIL. 
STOCKPILE EXCAVATED TOPSOIL IN APPROVED AREA OFF SITE. 
EXISTING AND IMPORTED TOPSOIL AMENDMENTS SHAll BE 
DETERMINED BY THE LANDSCAPE ARCHITECT AND APPROVED 
BY THE CITY ARBORIST. SOIL MIXING SHALL BE DONE IN 
DESIGNATED AREAS OR IN THE SUPPLIERS YARD. MIX 
AMENDMENTS WITH TOPSOIL WHEN SOIL IS IN A FRIABLE 
CONDITION ONLY: DAMP AND NOT MUDDY WITH ADEQUATE 
MOISTURE TO BREAK INTO CLODS W HEN TURNED AND Will 
NOT LEAVE A MUD STAIN ON THE HAND WHEN SQUEEZED. 
CONTRACTOR TO PROVIDE CERTIFICATE OF CONTENT AND 
PERCENT OF SOIL MIXES WITH ALL AMENDED SOIL TO THE CITY 
PRIOR TO INSTALLATION. 
BLENDED SOIL PLACEMENT AND COMPACTION: 
SOIL SHALL BE FRIABLE WHEN PLACED AND COMPACTED. 
PLACE SOIL IN LAYERS OF NOT MORE THAN 12" IN DEPTH. 
PROVIDE 3 PASSES WITH AT COMPACT PLATE VIBRATING 
COMPACTOR. COMPACT TO 80-85% MAXIMUM DRY DENSITY AS 
MEASURED BY THE PROCTOR TEST OR AS APPROVED FOR 
SPECIFIC BLENDED SOIL MIXES. 
CJ. 
(CF.) 
BOO 
BOO 
BOO 
BOO 
BOO 
BOO 
BOO 
BOO 
BOO 
BOO 
BOO 
STREET TREE WITH COVERED SOIL DETAIL 
I NOT TO SCALE 
STANDARD COVERED SOIL VOLUME SPECIFICATIONS: 
PART 1. COVERED SOIL MATERIALS 
A. COVERED SOIL SHALL CONSIST OF THE FOLLOWING MIXTURE OF GRAVEL. SOIL AND ADMIXTURES: 
I. CRUSHED ROCK, GRADATION OF 100% PASSING 1.25 1NCH, MAX. 30% PASSING 0.75 1NCH: 
II. LOAM/ORGANIC TOPSOIL: 
Ill. SOIL BINDER SUCH AS , ST ABillZER. : AND 
IV. WATER. 
PART 2. PROPORTIONS OF COVERED SOIL MATERIALS 
A THE PROPORTIONS OF COVERED SOIL MATERIALS SHALL BE AS FOLLOWS: 
AMOUNT FOR 1 CY AMOUNT FOR 4.6 CY 
MATERlAl OF COVERED SOIL OF COVERED SOIL 
CRUSHED ROCK 23.2 CUBIC FEET 4 CUBIC YARDS 
TOPSOIL 5.9 CUBIC FEET 1 CUBIC YARD 
SOIL BINDER 13.70Z 4 LBS 
WATER 1.6 GALLON 46 GALLONS 
B. THE TARGET MOISTURE CONTENT IS 20% BY WEIGHT OF THE TOPSOil WEIGHT. THE ABOVE WATER CONTENTS ASSUME THE TOP lS DRY. THE AMOUNT 
OF WATER THAT WILL NEED TO BE ADDED WILL BE DEPENDENT ON THE MOISTURE CONTENT OF THE RAW MATERIALS. ACTUAL AMOUNTS OF WATER 
USED SHALL BE DETERMINED DURING MIXING. 
PART 3. COVERED SOIL MIXING PROCEDURES 
A. MIX COVERED SOIL IN BATCHES OF AN APPROPRIATE SIZE FOR THE EQUIPMENT BEING USED. THE END RESULT IS TO BE A MATERlAL THAT IS 
UNIFORMLY BLENDED TOGETHER. DO NOT BATCH IN QUANTITIES THAT WILL NOT AllOW THE EQUIPMENT TO COMPLETELY MIX THE MATERIAL 
DETERMINE BATCH SlZE AND QUANTITIES OF EACH MATERIAL NEEDED FOR THE BATCH. 
B. START WJTH HALF O F THE CRUSHED ROCK MATERIAL. 
C. ADO All OF THE TOPSOIL MATERIAL. 
D. ADO THE SOIL BINDER. 
E. ADO HALF OF THE ESTIMATED WATER. 
F. ADO THE OTHER HALF OF THE CRUSHED ROCK MATERIAL 
G. MIX THE MATERIAL TOGETHER. 
H. SLOWLY ADD WATER TO THE MIXTURE AND CONTINUE TO MIX. THE FINAL AMOUNT OF WATER WILL VARY WITH MOISTURE CONTENT OF THE CRUSHED 
ROCK AND TOPSOIL. ADO WATER IN INCREMENTAl AMOUNTS AND MIX THE MATERIAl BETWEEN THE ADDITIONS OF WATER. 
I. STOP ADDING WATER AND MIXING WHEN THERE IS A MINUTE AMOUNT OF FREE TOPSOIL REMAJNING. THE TOPSOIL WILL COAT THE CRUSHED ROCK 
AND NOT FALL OUT OF THE MATERIAl. All OF THE CRUSHED ROCK SHALL BE UNIFORMLY COATED WITH TOPSOIL. THERE SHALL BE NO CLUMPS OF 
TOPSOIL OR UNCOVERED CRUSHED ROCK IN THE MIXTURE. 
J. IF TOO MUCH WATER IS ADDEO TO THE MIXTURE, WATER WILL DRAIN OUT OF THE MATERIAl AND THE TOPSOIL Will WASH OFF OF THE CRUSHED ROCK. 
IF THIS OCCURS THE BATCH OF MATERIAL SHALL BE DISCARDED AND SHALL NOT BE INCORPORATED INTO THE COMPLETED WORK. 
PART 4. PLACEMENT OF COVERED SOIL 
A PROTECT SOILS AND MIXES FROM ABSORBING EXCESS WATER AND FROM EROSION AT All TIMES. DO NOT STORE MATERIALS UNPROTECTED FROM 
RAINFALL EVENTS. DO NOT ALLOW EXCESS WATER TO ENTER SITE PRIOR TO COMPACTION. IF WATER IS INTRODUCED INTO THE MATERIAL AFTER 
GRADING, ALLOW MATERIAL TO DRAIN OR AERATE TO OPTIMUM COMPACTION MOISTURE CONTENT. 
B. All AREAS TO RECEIVE COVERED SOIL MIXTURE SHALL BE INSPECTED BY THE PROJECT LANDSCAPE ARCHITECT AND/OR PROJECT ENGINEER BEFORE 
STARTING PLACEMENT OF MIXTURE. All DEFECTS SUCH AS INCORRECT GRADING. COMPACTION AND INADEQUATE DRAINAGE. ETC .• SHAll BE 
CORRECTED PRIOR TO BEGINNING PLACEMENT OF COVERED SOIL 
C . CONFIRM THAT THE SUB-GRADE IS AT THE PROPER ELEVATION AND COMPACTED AS REQUIRED. SUB-GRADE ELEVATtONS SHAll SLOPE PARALLEL TO 
THE FINISHED GRADE. CLEAR THE EXCAVATION OF All CONSTRUCTION DEBRIS , TRASH, RUBBLE AND FOREIGN MATERIAL FILL ANY OVER EXCAVATION 
WJTH APPROVED FILL AND COMPACT TO THE REQUIRED SUB-GRADE COMPACTION. 
D. INSTAll COVERED SOIL IN 6-INCH LIFTS AND SPREAD UNIFORMLY OVER THE AREA. COMPACT EACH LIFT TO THE REQUIRED PERCENT OF MAXIMUM 
DENSITY. DELAY PLACEMENT 24 HOURS IF MOISTURE CONTENT EXCEEDS MAXIMUM AllOWABLE. PROTECT COVERED SOIL WITH PLASTIC OR PlYWOOD 
DURING DELAY. TAKE PARTICULAR CARE NOT TO DAMAGE UTILITIES WHEN INSTALLING COVERED SOIL COVERED SOIL THAT WILL BE THE BEOOING 
FOR UTILITY LINES SHALL BE COMPACTED TO CONFORM TO THE REQUIRED GRADE OF THE UTILITY LINE. DO NOT COMPACT THE IMMEDIATE VICINITY 
ABOVE A UTILITY LINE UNTil A FILL DEPTH OF AT LEAST 12~NCHES ABOVE THE UTILITY LINE IS REACHED. 
E. BRING COVERED SOILS TO FINISHED GRADES AS SHOWN IN THE APPROVED DRAWINGS. IMMEDIATELY PROTECT THE COVERED SOIL MATERIAL FROM 
CONTAMINATION BY WATER BY COVERING WITH PLASTIC OR Pl YWOOO. 
LOOP ROAD IMPROVEMENTS 
1011 SW LOOP ROAD 
. 07-11-2011 
JOe NU~BER 
1000 
HANCOCK ASSOCIATES 
1500 SW LOOP ROAD 
TIGARD. ell 9722J TIGARD OREGON 
~' \~P 4PE# SHEET APPENDIX 12 TAX LOT 1000 TAX WAP: 2S I 09.18 
City of Tigan.l Urban Forestry Code Rc,·isions I Volume 1\' I 95 
- - ~--
- - .... _-- T /,' ======--= .... -- - -_~-;?J;-~,:_:_1= 
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SCALE t " 
SCALE SHOWN IS FOR FUll 
SIZE SHEET ( 24"X361 ONLY 
EVISIONS: 
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'· 
W.OT--
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5,705 SF 
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w ?i • ' r -;---~ ----j i !--: 
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rYJ(:t)W: torr MIDI IN~ ____ ...,.. 
Cl.l~¢-
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8,173 SF 
EXAMPLE 
SOIL VOLUME PLAN 
FOR SINGLE LOT 
OIT ICE LOC\TEII J\T: 
1000 1ST STREEl . SLITE I 
TI GARH. OREr.ol'. 9 j22.1 
PH: (S0.1 J sss-xn x 
f AX: (50.'\l 5.'15--.:\X'( 
~ \f ~l l : 1'>1-l)j'.ARf_('()J I .\1\0RH I\ F.Cr-"t 
LI CE~SED I\ OR, U . & Ill 
DCV FOR IRRICAIDN 
LOT2 
5,056 SF 
~ 
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. 
t_i\SI~G, DRI'J(tl ~'l 
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IO'SEl!IICI< t--- -J 
-- _j 
I 
[_Y', t'!Dit~(. • \IOit-rcnr • f'l ,IS\JY', • L ... ,')-.(~ U<.11tm1toc 
SOIL LEGEND SOIL VOLUME CALCULATION FOR STREET TREES ADJACENT TO LOT 1 
~ 
r:7l 
LJ 
OPEN SOIL VOLUME 
TREE NUMBER 
COVERED SOIL VOLUME 
10023 
10024 
STREET TREE LEGEND 
SYMI30L 130TANICAL NAME 
SPECIES 
ARMSTRONG MAPLE 
ARf.lSTRONG MAPLE 
COMMON NAME 
OPEN SOIL COVERED SOIL TOTAl SOIL REQUIRED SOIL VOLME FOR 11' 
VOLUf.lE (C.F.) VOLUME (CF) VOLUf.lE (C.F.) RIGHT OF WAY (C.F.) 
6,453 45 6,498 500 
OVER 1,000 0 OVER 1,000 500 
CONDITION SIZE SPACING 
0 ACER RUBRUM 'ARMSTRONG' ARMSTRONG MAPLE B&B 2" CAL AS SHOWN 
COVERED SOl. VOlUME ROOT P'-TH 
PER SPECIFICATIOMS 
LRIOtfiOIFWAYWIOTH'-S~_j 
STREET TREE WITH COVERED SOIL DETAIL 
NOT TO SCALE 
ENCROACHMENT INTO THE ROOT PROTECTION ZONE IS ALLOWED WITH PROJECT ARBORIST 
APPROVAL AS DESCRIBED IN THE FOLLOWING NOTES: 
1. EXCAVATION IN THE TOP 24" OF THE SOIL IN THE CRITICAL ROOT ZONE AREA SHOULD BEGIN 
AT THE EXCAVATION LINE THAT IS CLOSEST TO THE TREE. 
2. THE EXCAVATION SHOULD BE DONE BY HAND/SHOVEL OR WITH A BACKHOE AND A MAN 
WITH A SHOVEL. PRUNING SHEARS. AND A PRUNING SAW. 
3. IF DONE BY HAND, All ROOTS 1" OR LARGER SHOULD BY PRUNED AT THE EXCAVATION LINE. 
4. 1F DONE WITH A BACKHOE (MOST LIKELY SCENARIO) , THEN THE OPERATOR SHALL START 
THE CUT AT THE EXCAVATION LINE AND CAREFULLY "FEEL" FOR ROOTS/RESISTANCE. WHEN 
THERE IS RESISTANCE, THE MAN WITH THE SHOVEL HAND DIGS AROUND THE ROOTS AND 
PRUNES THE ROOTS LARGER THAN 1" DIAMETER. 
IRRIGATION: 
IRRIGATION TO BE 'DESIGN-BUILD' BY THE LANDSCAPE CONTRACTOR. PROVIDE PLANS TO THE 
CITY FOR APPROVAL PRIOR TO BEGINNING INSTALLATION. 
REMOVAL, STORING, AND AMENDED SOILS FOR PLANTER AREAS: 
CONTRACTOR SHALL REMOVAL All DEBRIS FROM PLANTER AREAS AND EXCAVATE TO A 
DEPTH OF 36 1NCHES. SLOPE SIDES OF EXCAVATIONS AT 1:1 SLOPE OR SHORE EDGES TO 
PREVENT UNDERMINING OF VEHICLE LOAD AREAS AND TO PROVIDE A SLOPED PROFILE 
TRANSITION BETWEEN SOIL TYPES AND STRUCTURAL FILL. DISPOSE OF DEBRIS AND SUBSOIL. 
STOCKPILE EXCAVATED TOPSOIL IN APPROVED AREA OFF SITE. 
EXISTING AND IMPORTED TOPSOIL AMENDMENTS SHALL BE DETERMINED BY THE LANDSCAPE 
ARCHITECT AND APPROVED BY THE CITY ARBORIST. SOIL MIXING SHALL BE DONE IN 
DESIGNATED AREAS OR IN THE SUPPLIERS YARD. MIX AMENDMENTS WITH TOPSOIL WHEN 
SOIL IS IN A FRIABLE CONDITION ONLY ( DAMP AND NOT MUDDY WITH ADEQUATE MOISTURE 
TO BREAK INTO CLODS WHEN TURNED AND WILL NOT LEAVE A MUD STAIN ON THE HAND WHEN 
SQUEEZED) . CONTRACTOR TO PROVIDE CERTIFICATE OF CONTENT AND PERCENT OF SOIL 
MIXES WITH All AMENDED SOIL TO THE CITY PRIOR TO INSTALLATION. 
BLENDED SOIL PLACEMENT AND COMPACTION: 
SOIL SHALL BE FRIABLE WHEN PLACED AND COMPACTED. PLACE SOIL IN LAYERS OF NOT 
MORE THAN 12" 1N DEPTH. PROVIDE 3 PASSES WITH A 2" COMPACT PLATE VIBRATING 
COMPACTOR. COMPACT TO 80-85% MAXIMUM DRY DENSITY AS MEASURED BY THE PROCTOR 
TEST OR AS APPROVED FOR SPECIFIC BLENDED SOIL MIXES. 
STANDARD COVERED SOIL VOLUME SPECIFICATIONS: 
PART 1. COVERED SOIL MATERIALS 
A. COVERED SOIL SHALL CONSIST OF THE FOLLOWING MIXTURE OF GRAVEL. SOIL AND ADMIXTURES: 
I. CRUSHED ROCK, GRADATION OF 100% PASSING 1.25 INCH, MAX. 30% PASSING 0.751NCH: 
II. LOAM/ORGANIC TOPSOIL: 
Ill. SOIL BINDER SUCH AS , STABILIZER, ; AND 
IV. WATER. 
PART 2. PROPORTIONS OF COVERED SOIL MATERIALS 
A. THE PROPORTIONS OF COVERED SOIL MATERIALS SHALL BE AS FOLLOWS: 
MATERIAL AMOUNT FOR 1 CY OF COVERED SOIL AMOUNT FOR 4 CY OF COVERED SOIL 
CRUSHED ROCK 23.2 CUBIC FEET 4 CUBIC YARDS 
TOPSOIL 5.9 CUBIC FEET 1 CUBIC YARD 
SOIL BINDER 13.7 0 Z 4LBS 
WATER 1.6 GALLON 46GAUONS 
~ -
B. THE TARGET MOISTURE CONTENT IS 20% BY WEIGHT OF THE TOPSOIL WEIGHT. THE ABOVE WATER 
CONTENTS ASSUME THE TOP IS DRY. THE AMOUNT OF WATER THAT WILL NEED TO BE ADDED WILL BE 
DEPENDENT ON THE MOISTURE CONTENT OF THE RAW MATERIALS. ACTUAL AMOUNTS OF WATER 
USED SHALL BE DETERMINED DURING MIXING. 
PART 3. COVERED SOIL MIXING PROCEDURES 
A. MIX COVERED SOIL IN BATCHES OF AN APPROPRIATE SIZE FOR THE EQUIPMENT BEING USED. THE END 
RESULT IS TO BE A MATERIAL THAT IS UNIFORMLY BLENDED TOGETHER. DO NOT BATCH IN QUANTITIES 
THAT WILL NOT ALLOW THE EQUIPMENT TO COMPLETELY MIX THE MATERIAL. DETERMINE BATCH SIZE 
AND QUANTITIES OF EACH MATERIAL NEEDED FOR THE BATCH. 
B. START WITH HALF OF THE CRUSHED ROCK MATERIAL 
C. ADD ALL OF THE TOPSOIL MATERIAL. 
D. ADD THE SOIL BINDER. 
E. ADD HALF OF THE ESTIMATED WATER. 
F. ADD THE OTHER HALF OF THE CRUSHED ROCK MATERIAL. 
G. MIX THE MATERIAL TOGETHER. 
H. SLOWLY ADD WATER TO THE MIXTURE AND CONTINUE TO MIX. THE FINAL AMOUNT OF WATER WILL 
VARY WITH MOISTURE CONTENT OF THE CRUSHED ROCK AND TOPSOIL ADD WATER IN INCREMENTAL 
AMOUNTS AND MIX THE MATERIAL BETWEEN THE ADDITIONS OF WATER. 
STOP ADDING WATER AND MIXING WHEN THERE IS A MINUTE AMOUNT OF FREE TOPSOIL REMAINING. 
THE TOPSOIL WILL COAT THE CRUSHED ROCK AND NOT FALL OUT OF THE MATERIAL. All OF THE 
CRUSHED ROCK SHALL BE UNIFORMLY COATED WITH TOPSOIL. THERE SHALL BE NO CLUMPS OF 
TOPSOIL OR UNCOVERED CRUSHED ROCK IN THE MIXTURE. 
J. IF TOO MUCH WATER IS ADDED TO THE MIXTURE. WATER WILL DRAIN OUT OF THE MATERIAL AND THE 
TOPSOIL WILL WASH OFF OF THE CRUSHED ROCK IF THIS OCCURS THE BATCH OF MATERIAL SHALL BE 
DISCARDED AND SHALL NOT BE INCORPORATED INTO THE COMPLETED WORK. 
PART 4. PLACEMENT OF COVERED SOIL 
A. PROTECT SOILS AND MIXES FROM ABSORBING EXCESS WATER AND FROM EROSION AT ALL TIMES. DO 
NOT STORE MATERIALS UNPROTECTED FROM RAINFALL EVENTS. DO NOT AUOW EXCESS WATER TO 
ENTER SITE PRIOR TO COMPACTION. IF WATER IS INTRODUCED INTO THE MATERIAL AFTER GRADING, 
ALLOW MATERIAL TO DRAIN OR AERATE TO OPTIMUM COMPACTION MOISTURE CONTENT. 
B. ALL AREAS TO RECEIVE COVERED SOIL MIXTURE SHALL BE INSPECTED BY THE PROJECT LANDSCAPE 
ARCHITECTANDIOR PROJECT ENGINEER BEFORE STARTING PLACEMENT OF MIXTURE. ALL DEFECTS 
SUCH AS INCORRECT GRADING, COMPACTION AND INADEQUATE DRAINAGE, ETC .. SHALL BE 
CORRECTED PRIOR TO BEGINNING PLACEMENT OF COVERED SOIL 
C. CONFIRM THAT THE SUB-GRADE IS AT THE PROPER ELEVATION AND COMPACTED AS REQUIRED. 
SUB-GRADE ELEVATIONS SHALL SLOPE PARALLEL TO THE FINISHED GRADE. CLEAR THE EXCAVATION 
OF Al l CONSTRUCTION DEBRIS. TRASH, RUBBLE AND FOREIGN MATERIAl. FILL ANY OVER EXCAVATION 
WITH APPROVED FILL AND COMPACT TO THE REQUIRED SUB-GRADE COMPACTION. 
D. INSTALL COVERED SOIL IN 6-INCH LIFTS AND SPREAD UNIFORMLY OVER THE AREA COMPACT EACH 
LIFT TO THE REQUIRED MAXIMUM DENSITY. DELAY PLACEMENT 24 HOURS IF MOISTURE CONTENT 
EXCEEDS MAXIMUM ALLOWABLE, PROTECT COVERED SOIL WITH PLASTIC OR PLYWOOD DURING DELAY. 
TAKE PARTICULAR CARE NOT TO DAMAGE UTILITIES WHEN INSTAlliNG COVERED SOIL. COVERED SOIL 
THAT WILL BE THE BEDDING FOR UTILITY LINES SHALL BE COMPACTED TO CONFORM TO THE REQUIRED 
GRADE OF THE UTILITY LINE. DO NOT COMPACT THE IMMEDIATE VICINITY ABOVE A UTILITY LINE UNTIL 
A FILL DEPTH OF AT LEAST 12-INCHES ABOVE THE UTILITY LINE IS REACHED. 
E. BRING COVERED SOILS TO FINISHED GRADES AS SHOWN IN THE APPROVED DRAWINGS. IMMEDIATELY 
PROTECT THE COVERED SOIL MATERIAL FROM CONTAMINATION BY WATER BY COVERING WIT PLASTIC 
OR PLYWOOD. 
. 07-11-2011 
JOHNSI.I11H 
PO BOX 111 
AS SHOWN 
TIGARD, mEGOH 9722J 
Pit 503-909-5555 
FU 503-iO!I-5556 
EVERGREEN HEIGHTS PARTITION 
190 SW 147TH ST. ~' ~ JOHN H. DOE t; %OREGON~ 
~ NUUBER 
2001 
SHEET 
APPENDIX 13 TIGARD TAXI.OT 1700 OREGON 4PE# T AXlW' 2 4E 25 
City of Tigard Urban Fore, try Code Rc,·i, iom I \' olumc I\' I 97 
(9 
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0 CD l .,---.+--
0 1) ', , ) , , ,,v b , , .l 
TYPICAL LANDSCAPED FRONT 
YARD (OPEN SOIL VOLUME) 
OPEN SOIL VOLUME 
ROOT BARRIER PER 
:Jio ,"\: MANUFACTURER'S 
SPECIFICATIONS 
STREET 
COVERED SOIL 
VOLUME ROOT PATH 
(MINIMUM WIDTH 3') 
--+--DRIVEWAY 
,.-,---~·'\ 
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--- 1 /1 -- 7 
// 
-.~_ 
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PLAN 
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VOLUME 
~ 
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COVERED SOIL VOLUME ROOT PATH 
PER CITY SPECIFICATIONS 
ROOT BARRIER PER MANUFACTURER'S 
SPECIFICATIONS 
L L COMPACTED SUBGRADE RIGHT OF WAY WIDTH VARIES_j 
PROFILE 
City of Tigard Urban Forestry Code Re,·isions I \'olumc I\' I 99 
EXAMPLE COVERED SOIL VOLUME 
PLAN DRAWING - ROOT PATH 
OPTION FOR STREET TREE 
NO SCALE 
DWG. NO. 
APPENDIX 14 
Example Covered Soil Volume Specifications 
Part 1. Covered Soil Materials 
A. Covered soil shall consist of the following mixture of gravel, soil and admixtures: 
1. Crushed rock, gradation of 100% passing 1.25 inch, max. 30% passing 0.75 inch; 
2. Loam / O rganic Topsoil; 
3. Soil binder such as "Stabilizer"; and 
4. Water. 
Part 2. Proportions of Covered Soil Materials 
A. The proportions of covered soil materials shall be as follows: 
Material Amount for 1 CY Amount for 4.6 CY 
of Covered Soil of Covered Soil 
Crushed Rock 23.2 cubic feet 4 cubic yards 
Topsoil 5.9 cubic feet 1 cubic yard 
Soil Binder 13.7 ounces 4 pounds 
Water 1.6 gallon 46 gallons 
B. The target moisture content is 20% by weight of the topsoil weight. The above water 
contents assume the top is dry. The amount of water that will need to be added will be 
dependent on the moisture content of the raw materials. Actual amounts of water used shall 
be determined during mixing. 
Part 3. Covered Soil Mixing Procedures 
A. Mix covered soil in batches of an appropriate size for the equipment being used. The end 
result is to be a material that is uniformly blended together. D o not batch in quantities that 
will not allow the equipment to completely mix the material. D etermine batch size and 
quantities of each material needed for the batch. 
B. Start with half of the crushed rock material. 
C. Add all o f the topsoil material. 
D . Add the soil binder. 
E. Add half of the estimated water. 
F. Add the other half of the crushed rock material. 
G. Mix the material together. 
H . Slowly add \Vater to the mixture and continue to mix. The flnal amount of water will vary 
with moisture content of the crushed rock and topsoil. Add water in incremental amounts 
and mix the material between the additions of water. 
I. Stop adding water and mixing when there is a minute amount of free topsoil remaining. The 
topsoil will coat the crushed rock and no t fall out of the material. All of the crushed rock 
Appendix 14 
City of Tigard Urban Forestry Code Re\'isions I Volume IV I 101 
shall be uniformly coated with topsoil. There shall be no clumps of topsoil or uncovered 
crushed rock in the mixture. 
]. If too much water is added to the mixture, water will drain out o f the material and the 
topsoil will wash o ff of the crushed rock. If this occurs the batch of material shall be 
discarded and shall no t be incorporated into the completed work. 
Part 4. Placement of Covered Soil 
A. Protect soils and mixes from absorbing excess water and from erosion at all times. D o not 
store materials unprotected from rainfall events. Do not allow excess water to enter site 
prior to compaction. If water is introduced into the material after grading, allow material to 
drain or aerate to optimum compaction moisture content. 
B. All areas to receive covered soil mixture shall be inspected by the project landscape architect 
and/ or project engineer before starting placement of mixture. All defects such as incorrect 
grading, compaction and inadequate drainage, etc. , shall be corrected prior to beginning 
placement o f covered soil. 
C. Conftrm that the sub-grade is at the proper elevation and compacted as required. Sub-grade 
elevations shall slope parallel to the finished grade. Clear the excavation o f all construction 
debris, trash, rubble and foreign material. Fill any over excavation with approved fill and 
compact to the required sub-grade compaction. 
D . Install covered soil in 6-inch lifts and spread uniformly over the area. Compact each lift to 
the required percent of maximum density. Delay placement 24 hours if moisture content 
exceeds maximum allowable, protect covered soil with plastic or plywood during delay. 
Take particular care no t to damage utilities when installing covered soil. Covered soil that 
will be the bedding for utility lines shall be compacted to conform to the required grade of 
the utility line. D o not compact the immediate vicinity above a utili ty line until a fill depth of 
at least 12-inches above the utility line is reached. 
E. Bring covered soils to finished grades as shown in the approved drawings. Immediately 
protect the covered soil material from contamination by water by covering with plastic or 
plywood. 
Appendix 14 
Cit:r of 'l'iganl Urban l'orcstry CoJ c Rc,·isions I \'olumc I \ ' I 102 
OPEN SOIL VOLUME 
TREE 'A' 
34' 
D 
PLAN 
PARKING LOT SURFACING 
COM PACTED SUBGRADE 
PROFILE 
TOTAL SOIL VOLUME CALCULATION FOR TREE 'A': 
OPEN SOIL VOLUME= (ISLAND AREA) X (SOIL DEPTH)= 336 S.F. 
X 3' = 1,008 C.F. 
COVERED SOIL VOLUME = 0 C. F. 
TOTAL SOIL VOLUME = OPEN SOIL VOLUME + COVERED SOIL 
VOLUME = 1,008 C.F. + 0 C. F. = 1,008 C.F. 
1,008 C. F. IS GREATER THAN THE SOIL VOLUME REQUIRED FOR 
A PARKING LOT TREE (1 ,000 C.F.) SO THIS MEETS THE CITY 
REQUIREMENTS. 
EXAMPLE SOIL VOLUME 
CALCULATION - PARKING 
LOT TREE WITH OPEN SOIL 
City of Tigard Urban Forestry Code Re,·isiom I Volume IV I 103 
NO SCALE 
DWG. NO. 
APPENDIX 15 
OPEN SOIL VOLUME 
+ 
3
·---}::l v / /1 ~~3~TREE 'A' 
I 
35' 
+ 
1 
r // / J 
1 
+ 1 COVERED SOIL VOLUME I + + + r UNDER ASPHALT 
;n 
+ + 
+ + 
+ 
+ 
+ 
+ + 
+ 
PLAN 
OPEN SOIL VOLUME 
3'·--+---' PARKING LOT SURFACING 
DRAINAGE 
PROFILE 
TOTAL SOIL VOLUME CALCULATION FOR TREE 'A': 
OPEN SOIL VOLUME= (PLANTER AREA) X (SOIL DEPTH) = 196 S.F. 
X 3' = 588 C.F. 
COVERED SOIL VOLUME= 259 S.F. X 3' = 777 C.F. 
TOTAL SOIL VOLUME= OPEN SOIL VOLUME+ COVERED SOIL 
VOLUME= 588 C. F.+ 777 C.F. = 1,365 C.F. 
1,365 C. F. IS GREATER THAN THE SOIL VOLUME REQUIRED FOR A 
PARKING LOT TREE (1 ,000 C. F.) SO THIS MEETS THE CITY 
REQUIREMENTS. 
EXAMPLE SOIL VOLUME 
CALCULATION - PARKING LOT 
TREE WITH COVERED SOIL 
City oi TiganJ Urban l'orc>try Code Rc,·i>iom I \ 'olumc I\ ' I 104 
NO SCALE 
DWG. NO. 
APPENDIX 15 
TOTAL SOIL VOLUME CALCULATION FOR TREE 'A': 
OPEN SOIL VOLUME= 36 S.F. (TREE CUTOUT AREA)+ 36 S.F (CONNECTED TREE CUTOUT AREA) x 3' (SOIL DEPTH) = 216 C.F. 
COVERED SOIL VOLUME= 330 S.F. (COVERED SOIL AREA) X 3' (COVERED SOIL DEPTH' =990 C.F 
TOTAL SOIL VOLUME= OPEN SOIL VOLUME+ COVERED SOIL VOLUME= 216 C.F. + 990 C.F.=1 ,206 C.F. 
1,206 C. F. IS GREATER THAN THE SOIL VOLUME REQUIRED FOR A PARKING LOT TREE (1000 C. F) SO THIS MEETS THE CITY 
REQUIREMENTS. 
I 
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50' 
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' ... 
---
Rl l'',r ,,, ___ 
6'X6' TREE CUTOUT 
(OPEN SOIL VOLUME) 
--·-- .......... 
... 
TREE 'A' 
6'X6' TREE CUTOUT 
(OPEN SOIL VOLUME) 
... 
... 
-- ~ ~~ r / r · 
' 
., 
' 
' 
" ., 
' 
" 
' 
' 
' \ 
, 
I 
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CONNECTED TREE CUTOUT 
(OPEN SOIL VOLUME) 
EXAMPLE SOIL VOLUME 
CALCULATION - PARKING 
LOT TREE WITH ROOT PATH 
NO SCALE 
DWG. NO. 
APPENDIX 15 
City of Tigard Urban Forestry Code Rc,·isions I Volume 1\' I 105 

I 
I 
I' 
/ 
EVISIONS: 
~ ,_ 
I 
/1 
/ 
W1£El STOPS 
- - -
_, 
...._._ 
...._._ 
...._._ 
~ 
I 
IIAT\IRE CANOPI 
-;:: C(MR 
' 50' IIATURE 
'1-- CAN0P1 SPREAD 
I 
- - -
PLANT LEGEND 
SYWBO\. OTIES. ilQT~ICAl NAil[ COIIt.IOH NAil[ SIZE COiflo'OO!' SPACING 
AVERAG£ IIATUR£ 
CANOPI ~ZE 
...._._ 0 8 0 
BUILDING FOOTPRINT 
ACER RUiflUM 
OUERt\IS RUBRA 
28 ZELJ(QYA S!JlRATA 
REO IIAP1.E 
RED (Ill( 
Z[U(OYA 
" ~, 
" 
" 
" 
" 
2" CAL 
2" CAL 
2" CAL 
~> 
" 
" 
" 
" 
8.1:8 
Bd<B 
B.tB 
~-
" 
" 
" 
1-S SHOWN 40' SPil£AD (1.256 s.r.) 
1-S SHOWN 45' SPil£AD (1.590 s.r.) 
1-SSI«>WN so' SPil£AD (1,96J s.r.) 
SCALE SHOWN IS FOR FULL 
SIZE SHEET ( 24.X36") ONLY 
SCALE 1" - 20 FEET 
---~ ~ '" ~ 
TREE CANOPY TABLE 
TREE II 
001 
002 
003 
004 
005 
006 
007 
008 
000 
010 
011 
0012 
0013 
001 4 
0015 
0010 
0017 
0018 
0010 
0020 
0021 
0022 
0023 
0024 
0025 
0020 
0027 
0028 
0020 
0030 
0031 
0032 
0033 
0034 
0035 
0030 
0037 
0038 
0030 
0040 
0041 
0042 
~ OPEN SOIL VOLUME COVERED SOIL VOLUME TOTAL SOIL VOLUME AVE. MATURE CANOPY % OF CANOPY OVER PARKING LOT AREA OVER PARKING LOT 
Zelko \a 
Red Oak 
Zelko\8 
Zelko loB 
Zelkow 
Zelko\8 
Zelko \a 
Zelkow 
Zelko\8 
Red Oak 
Zelko\8 
Zelko\& 
Zelko\8 
Zelko\8 
Red Oak 
Zelkow 
Zelkow 
Zelko\8 
Zelko ..a 
Red Oak 
Zetkow 
Zelkow 
Zelkow 
Zelko-.e 
Zelkow 
Zelko\8 
Red Oak 
Zelko\8 
Zelko\8 
Zelkow 
Red Oak 
Zelko\8 
Red Oak 
Zelko\8 
Red Maple 
Red Maple 
Red Maple 
Red Maple 
Red Maple 
Red Maple 
Red Maple 
Zelkow 
5.4UCT 
4,53Qc.f. 
3. 102 c. f 
3,oeo c t 
1,818c.f. 
303c .f. 
348c.f. 
570c .f. 
3,081 c.f. 
4.200 c.f 
708c .f 
3.051 c.f 
1,101 c. f. 
1,101 c.f. 
4, 155 c.f. 
4,170 c.f 
4,233c.f. 
4,233c.f. 
3,030c.f. 
4,500 c. f. 
417c .f. 
444c.f. 
4.2Q3c.f. 
4 ,284 c.f 
4,284 c. f. 
5,040 c .l. 
3,702c.f 
2,430c .f. 
1,077c.f. 
1,077 c. f. 
4, 1Q1 c.f. 
3,030c.f. 
4,31'il2c.f 
7,350c .f 
1, 41 0c.f 
1,Q8Qc.f 
2.5e2c.f 
2,52Qc.f. 
1,533c.f 
510c.f. 
510 c .f. 
837c .f. 
Oc .f 
Oc.f. 
o c. f. 
Oc .f. 
Oc.f. 
2.100c.f 
2,1COc.f. 
2. tee c.f. 
Oc.f. 
Oc .f. 
2.070c.f. 
Oc.f. 
Oc.f. 
Oc .f. 
Oc .f. 
Oc.f. 
Oc.f. 
Oc.f. 
Oc.t. 
Oc .t. 
870 c.f. 
870c.f. 
670c.f 
870c.f. 
670c.f. 
Oc.f. 
Oc.f. 
Oc.f. 
Oc.f. 
Oc.f. 
Oc.f. 
Oc.f. 
Oc.f. 
Oc.f. 
Oc .t. 
Oc.f. 
Oc.f. 
Oc.f 
Oc.f 
1,710 c .f. 
1,710c.f. 
441 c .f. 
5,4eec .f. 
4,53Qc.f. 
3,1Q2c.f. 
3,0CQc.f. 
1,818 c.f. 
2.4C3c .f. 
2,508c.f 
2,742c.f. 
3,081 c.f. 
4,200c.f. 
2.784 c. f. 
3,051 c.f. 
1,101 c.f. 
1,101 c. f. 
4,155c.f. 
4,170c.f. 
4,233c.f. 
4,233c.f. 
3.030c.f. 
4,50Cc.f. 
1,287 c.f. 
1.314 c .f. 
5,103c .f. 
5,154 c.f. 
5,154 c.f. 
5,040 c. f. 
3,702c .f. 
2,430c.f. 
1,077c.f. 
1,077c.f. 
4, 1Q1 c.f. 
3,030 c . f. 
4,31'il2c.f 
7,350 c.f 
1,410c.f 
1,Q8Qc.f 
2.5e2c.f 
2.52Q c . f. 
1,533c.f 
2.232c.f. 
2.232 c. f. 
1,278 c.f. 
-·- - ,._ ___ .. 
50' s!)fead (1 ,0«53 s.f) 
45' spread (1 ,5QO s.f. ) 
50' spread (1,QC3 sf) 
50' s!)fead (1,083 s.f ) 
50' spread (1 ,0«53 s. f.) 
50' spread (1 ,QC3 s.f.) 
50' spread (1 ,903 s.f.) 
50' spread (1 ,003 s.f.) 
50' spread (1,083 s.f.) 
45' spread (1.5QO s.f.) 
50' spread (1 ,003 s.f.) 
50' spread (1 ,QC3 s.f.) 
50' spread (1.003 s.l.) 
50' spread (1.QC3 s.t. ) 
45' spread (1 ,5QO s.l.) 
50' spread (1 ,0«53 s.f.) 
50' SPfead (1 ,QC3 s.f. ) 
50' SPfead (1 ,003 s.f.) 
50' spread (1,QC3 s.t. ) 
45' spread (1 ,5QO s.f.) 
50' spread (1,903 s.f.) 
50' spread (1 ,0«53 s.f.) 
50' spread (1,QC3 s. f.) 
50' spread (1,QC3 s.f) 
50' spread (1 ,903 s.f.) 
50' spread (1 ,9C3 s.f.) 
45' spread (1 ,5QO s.f.) 
50' spread (1,QC3 s.f.) 
50' spread (1 ,903 s.f.) 
50' spread (1 ,QC3 s.f.) 
45' spread (1 ,5QO s.f.) 
50' spread (1 ,oe3 s.f ) 
45' spread (1 ,5QO s .f.) 
50' spread (1,903 s .f.) 
40' spread (1,25e s.f.) 
40' spread (1 ,25e s.f.) 
40' spread (1 ,250 s.f.) 
40' spread (1 ,25e s.f.) 
40' spread (1,25e s.f. ) 
40' spread (1 ,250 s.f. ) 
40' spread (1,250 s.f.) 
50' spread (1,003 s.f.) 
"""' 40%
.,... 
..... 
53% 
50% 
80% 
85% 
70% 
35% 
82% 
,. ... 
100% 
100% 
30% 
100% 
100% 
100% 
,. ... 
41% 
100% 
100% 
100% 
100% 
100% 
48% 
37% 
,..,. 
100% 
100% 
40% 
80% 
38% 
45% 
100% 
100% 
100% 
73% 
58% 
81% 
80% 
02% 
757s .f 
C40s .f. 
1,612 s f. 
t ,74Qs f . 
1,040s.f . 
Q84 s .f. 
1,575 s.f 
1,eea sf. 
1,4QS s.f 
55Q sf 
1,013s f 
1,550 s.f. 
Ul03s.f 
t,QC3s.f. 
see s.f. 
1,QC3 s.t. 
1,QC3 sf. 
t ,QC3 s.f. 
1,547s.f 
844 s.f. 
t ,QC3s.f. 
1,QC3 s. f. 
1,QC3 s.f. 
1,QC3s.f. 
1,QC3 s f 
Q3Cs .l. 
581 s .f. 
t ,556 s .f. 
1,QC3s.f. 
t ,QC3s.f. 
C42s .f. 
1.5e3 s.f. 
002 s.f. 
862 s.f. 
1.2se s.f. 
t ,25e s.f. 
1,25Cs.f 
Qt5 s.f. 
720 s.f. 
1,021 s.f. 
1,007 s.f. 
1,604 s.f. 
Total Qualifying Mature Tree Canopy Area: 57,7C3 s.f. 
( S~.n~ of canopy area o-.er panting lot) 
QUAliFYING MATURE CANOPY INCLUDES All AREAS OIRECTL Y OVER THE PARKING LOT SURFACE AND AREAS THAT ARE SURROUNDED ON AT LEAST THREE SIDES BY EITHER CURB OR 
HARD SURFACE PAVlNG. THIS INCLUDES BUT IS NOT LIMITED TO PARKING LOT ISLANDS AND PLANTING AREAS BETWEEN THE PARKING LOT AND SIDEWALK. 
D QUALIFYING MATURE CANOPY COVER 
INDMDUAL TREE MATURE CANOPY OUTLINE 
PARKING LOT AREA: 64,962 S.F. 
TOTAL QUALIFYING MATURE TREE CANOPY AREA•: 57,763 S.F. 
( CANOPY AREA DIRECTLY OVER PARKING LOl) 
% CANOPY COVER: 89% 
MINIMUM % CANOPY COVER: 30% 
89% IS GREATER THAN THE MINIMUM OF 30% TOTAL QUALIFYING 
MATURE CANOPY COVER THEREFORE CITY REQUIREMENTS ARE 
MET. 
REMOVAL, STORING, AND AMENDED SOILS FOR PLANTER AREAS: 
• OPEN SOIL VOLUME 
COVERED SOIL VOLUME 
PARKING LOT TREE SOIL VOLUME REQUIREMENTS 
---·-·- . - - ---~ ~---MIN. SOIL VOLUME REOUiru:M~n • ~~....r. r~" ' "~~ 
1,000 C.F. 
CONTRACTOR St-W..L REMOVAL All DEBRIS FROM PLANTER AREAS AND EXCAVATE TO A DEPTH OF 36 /NCHES. SLOPE SIDES OF EXCAVATIONS AT 1:1 SLOPE OR 
SHORE EDGES TO PREVENT UNDERMINING OF VEHICLE LOAD AREAS AND TO PROVIDE A SLOPED PROFILE TRANSITION BETWEEN SOIL TYPES AND STRUCTURAL 
FILL. DISPOSE OF DEBRIS AND SUBSOIL. STOCKPILE EXCAVATED TOPSOIL IN APPROVED AREA OFF SITE. 
EXISTING AND IMPORTED TOPSOIL AMENDMENTS SHALL BE DETERMINED BY THE LANDSCAPE ARCHITECT AND APPROVED BY THE CITY ARBORIST. SOIL MlXJNG 
SHAll BE DONE IN DESIGNATED AREAS OR IN THE SUPPLIERS YARD. MIX AMENDMENTS WITH TOPSOIL WHEN SOIL IS IN A FRIABLE CONDmoN ONLY ( DAMP AND 
NOT MUDDY WITH ADEQUATE MOISTURE TO BREAK INTO CLODS WHEN TURNED AND WILL NOT LEAVE A MUD STAIN ON THE HAND WHEN SOUEEZEO, . 
CONTRACTOR TO PROV1DE CERTIFICATE OF CONTENT AND PERCENT OF SOIL MIXES WITH All AMENDED SOIL TO THE CfTY PRK>R TO INSTAllATION. 
BLENDED SOIL PLACEMENT AND COMPACTtoN: 
SOIL SHALL BE FRIABLE WHEN PLACED AND COMPACTED. PLACE SOIL IN LAYERS OF NOT MORE THAN 1 2~ IN DEPTH. PROVIDE 3 PASSES WITH A 'Z' COMPACT 
PLATE VIBRATING COMPACTOR. COMPACT TO ~5% MAXIMUM DRY DENSITY AS MEASURED BY THE PROCTOR TEST OR AS APPROVED FOR SPECIFIC BLENDED 
Sotl MIXES. 
~ 
PARKING LOT SURFACING 
, ~ qF-.1 I!~! I~~ I f=;=l 151 I ~J COVERED SOIL VOLUME 
-p""'jj''~,,,___ COMPACTED SUBGRADE 
PARKING TREE WITH COVERED SOIL DETAIL 
NOT TO SCALE 
. 07-11-2011 
EXAMPLE PARKING LOT 
TREE CANOPY PLAN 
OFF I CE LOC-'lEil .n : 
1000 1ST STREET. Sl'ITE I 
TI GAIU>, OREGON 9722:1 
~lj!!!.ll!!n lur ~<.NOTED 1 ABc COLLABORATTVE LOOP ROAD IMPROVEMENTS 1011 SW LOOP ROAD ~' 
JOB NUWBER 
1000 
PH: (!l03l 555-XX\:X 
rA.\: (!lO:ll 555-XX XX 
TIGARD 
Dlo\! L: INJ"(WrAHC_MLL.ABORAT ! VE. f'0\1 
LH'E'lSED l fo. nR, I 'A. l II) f'l'f.I\-R''«i • UIO!ITFl'111f o N~~IIW. • 1 \\l'(';('Af'~ 'IRf'HrTrrff 
TAX LOT 1000 
City of Tigard Urban Forestry Code Rc,·isions I \'olumc I\' I 107 
OREGON 
TAX WAP 25 1 09AB 
. . 
~ JO!IIH.DO£ t % OREGC!'J ~ 
4PE# 
SHEET 
APPENDIX 16 
LANDSCAPE ISLAND (OPEN SOIL VOLUME) 
~ -r--T ~+~ 't- ~ ~ 
4- + + + + + + + + + + I COVERED SOIL VOLUME 
r 
+ + + + + + + + + + yJ UNDER ASPHALT 
+ + + + + + + + +. 
+ + + + + + + + + + 
++++ ++++ 
I + + + + + + ~ 
f+- ++ +++ I 
+ + + + + 
~ + + + + I 
I + + + + -tJ 
+ + + + + 
i. + + + + 1 r- + + + + 
_, v'ARrE~ 't'ARi!EsH-
[ 
+ ~ + + 1 
+ + + + 
+ + + + 
I. + + r- + + 
+ + 
+ + 1 
+ + 
+ + -+' 
+ + 1 + + 
+ + 
r
+ + + + ]+. 
+ + + + 
+ + + + 
+ + + + + + 
I + + + + + ~ 
f+- +++ +++ I 
++++ + + ++ 
~ + + + + + + + + + I 
I + + + + + + + + + + -tJ 
+ + + + + + + + CIJRB + 
1 ++++++++++ -ti 
L--l ~ ·~ ~ · ----1..- ~ ----L....J 
PLAN 
PARKING LOT SURFACING 
PROFILE 
EXAMPLE COVERED SOIL VOLUME 
PLAN DRAWING - UNDER 
PARKING LOT OPTION FOR 
PARKING LOT TREE 
City of Tigard Urban Forestry Code Re,·isions I \' olume I\' I 109 
NO SCALE 
DWG. NO. 
APPENDIX 17 
PLAN 
COVERED SOIL VOLUME 
ROOT PATH (3' MIN IMUM ) 
6'X6' MINIMUM TREE CUTOUT 
(OPEN SOIL VOLUME) 
NNECTED TREE CUTOUT 
t----+;----t- VARI ES t----t-----t 
URB 
6'X6' MIN IMUM TREE CUTOUT 
(OPEN SOIL VOLUME) 
PLAN 
CONNECTED TREE CUTOUT 
(OPEN SOIL VOLUME) 
PROFILE 
COVERED SOIL VOLUME (ROOT PATH) 
PER CITY SPECIFICATIONS 
EXAMPLE COVERED SOIL 
VOLUME DRAWING- ROOT 
PATH OPTION FOR PARKING 
LOT TREE 
CitY of 'l'igard Urban l'orcstry Code Rc,·isions I \'olumc I\ ' I 111l 
NO SCALE 
DWG. NO. 
APPENDIX 17 
Standard Covered Soil Volume Specifications 
Part 1. Covered Soil Materials 
A. Covered soil shall consist of the following mixture of gravel, soil and admixtures: 
1. Crushed rock, gradation of 100% passing 1.25 inch, max. 30% passing 0.75 inch; 
2. Loam / O rganic Topsoil; 
3. Soil binder such as "Stabilizer"; and 
4. Water. 
Part 2. Proportions of Covered Soil Materials 
A. The proportions of covered soil materials shall be as follows: 
Material Amount for 1 CY Amount for 4.6 CY 
of Covered Soil of Covered Soil 
Crushed Rock 23.2 cubic feet 4 cubic yards 
Topsoil 5.9 cubic feet 1 cubic yard 
Soil Binder 13.7 ounces 4 pounds 
Water 1.6 gallon 46 gallons 
B. The target moisture content is 20% by weight of the topsoil weigh t. The above water 
contents assume the top is dry. The amount of water that will need to be added will be 
dependent on the moisture content of the raw materials. Actual amounts of water used shall 
be determined during mixing. 
Part 3. Covered Soil Mixing Procedures 
A. Mix covered soil in batches of an appropriate size for the equipment being used. The end 
result is to be a material that is uniformly blended together. D o not batch in quantities that 
will not allow the equipment to completely mix the material. D etermine batch size and 
quantities of each material needed for the batch . 
B. Start with half of the crushed rock material. 
C. Add all o f the topsoil material. 
D . Add the soil binder. 
E . Add half of the estimated water. 
F. Add the other half of the crushed rock material. 
G . Mix the material together. 
H . Slowly add water to the mixture and continue to mix. The final amount of water will vary 
with moisture content of the crushed rock and topsoil. Add water in incremental amounts 
and mix the material between the additions of water. 
I. Stop adding water and mixing when there is a minute amount of free topsoil remaining. The 
topsoil will coat the crushed rock and not fall out of the material. All of the crushed rock 
Appendix 17 
City of Tigard Urban Forestry Code Rc\'isions I Volume 1\' 1 111 
shall be uniformly coated with topsoil. T here shall be no clumps of topsoil or uncovered 
crushed rock in the mixture. 
J. If too much water is added to the mixture, water will drain out o f the material and the 
topsoil will wash off of the crushed rock. If this occurs the batch o f material shall be 
discarded and shall not be incorporated into the completed work. 
Part 4. Placement of Covered Soil 
A. Pro tect soils and mixes from absorbing excess water and from erosion at all times. D o no t 
store materials unpro tected from rainfall events. D o no t allow excess water to enter site 
prior to compaction. If water is introduced into the material after grading, allow material to 
drain or aerate to optimum compaction moisture content. 
B. All areas to receive covered soil mixture shall be inspected by the project landscape architect 
and/ or pro ject engineer before starting placement o f mL'<ture. All defects such as incorrect 
grading, compaction and inadequate drainage, etc., shall be corrected prior to beginning 
placement o f covered soil. 
C. Conftrm that the sub-grade is at the proper elevation and compacted as required. Sub-grade 
elevations shall slope parallel to the fmished grade. Clear the excavation o f all construction 
debris, trash, rubble and foreign material. Fill any over excavation with approved fill and 
compact to the required sub-grade compaction . 
D . Install covered soil in 6-inch lifts and spread uniformly over the area. Compact each lift to at 
leas t 85 percent o f maximum density. Delay placement 24 hours if moisture content exceeds 
maximum allowable, protect covered soil with plastic or plywood during delay. Take 
particular care not to damage utilities when installing covered soil. Covered soil that will be 
the bedding for utility lines shall be compacted to conform to the required grade o f the 
utility line. D o no t compact the immediate vicinity above a utili ty line until a fill depth of at 
least 12-inches above the utili ty line is reached. 
E. Bring covered soils to ftnished grades as shown in the approved drawings. Immediately 
pro tect the covered soil material from contamination by water by covering with plas tic or 
plywood. 
Appendix 17 
Cin· of Tigard Urban l'orcstn· Code Rc,·isions I \ 'olumc I\ ' I 11 2 
I 
I 
\ 
\ 
SIDEWALK 
PLANTER 
\ 
\ 
' 
' 
-
ARKING AREA BOUNDARY 
-
' 
/ 
WHITE ASH (TYP.) 
\_ 45' DIA. MATURE CANOPY (TYP.) 
1,590 S.F. 
' 
' \ 
I 
I 
I 
123.00' 
RED MAPLE (TYP.) 
40' DIA. MATURE CANOPY (TYP.) 
' I 
f 1,256 S.F. 
' \ 
I 
I 
I 
' . 
/ 
' 
/ 
' 
/ 
- - ' - -
/ 
TOTAL CANOPY AREA OF PARKING LOT TREES* = 11 ,388 S.F. 
TOTAL QUALIFYING MATURE CANOPY COVER= CANOPY COVER DIRECTLY OVER THE PARKING AREA IN SQUARE 
FEET, INCLUDING PLANTING ISLANDS AND AREAS SURROUNDED BY CURB OR HARD SURFACE PAVING ON AT 
LEAST THREE SIDES. 
li2Sl TOTAL QUALIFYING MATURE CANOPY COVER= 8,057 S.F. 
PARKING LOT AREA= 13,590 S.F. 
PERCENT ACTUAL CANOPY COVER= (8,057 S.F.) I (13,590 S.F.)= 59% 
59% IS GREATER THAN THE MINIMUM OF 30% TOTAL QUALIFYING MATURE CANOPY COVER 
THEREFORE CITY REQUIREMENTS ARE MET. 
*CANOPY AREA PER TREE IS DETERMINED FROM THE VALUE GIVEN IN THE CITY OF T IGARD PARKING LOT TREE 
LIST FOR A MATURE TREE OF THAT SPECIES. 
EXAMPLE PARKING LOT 
THAT MEETS 30% MINIMUM 
CANOPY COVER 
REQUIREMENT 
City of Ti!,'<l rd Urban Forestry C:odc Rc,·isions I \'olumc I\ ' I 11 3 
NO SCALE 
DWG. NO. 
APPENDIX 18 
City of Tigard 
COMMUNITY DEVELOPMENT DEPARTMENT 
13125 SW Hall Blvd., Tigard, OR 97223 
www. tigard-or.gov / trees I 
Volume V: Table of Contents 
Organization of the Urban Forestry Code Revisions D ocuments 1 
Planning Comnussion Deliberations .......................... .......... ... .............. .. ..... ............................ ......... .............. 3 
Amendment Requests D ocument for the Planning Comnlission 
Outstanding Issues for the Urban Forestry Code Revisions .... ..... ........ ... ....... ... .. ....... ... .... ........ .. .. .... ....... 73 
Log of Input 
CAC Guiding Principles ..... ..... ..................... .. .. ... .... ..... .... ......... ..... .... ...... ... ....... ..... ............ ... ... ..... .. .. .. ... .... 139 
Tree Values .. ..... ........ ...... ........... .... .. .. ... ..... ....... .......... .. ... ... .... ..... ............... ........ ... ..... ....... .... ...... .... ... .. .. ...... . 149 
Canopy Standards .. ...... .. ............... .................... ..... ..... ... ..... ....... ......... ...... ......... ............. ...... ... .. .............. ..... 159 
Soil Volume .... ................ ....... .............. ........ ......... .... .. .. ....... .... ..... ........ .... ......... ......... .... ..... ...... ... .. .. ... .. .. ...... 167 
Tree Canopy Fee .. ...... ....... ... ..... ... .... .... .... ........... .... ........ ... .. ...... .... .. ... ..... .... .. ...... .... .. ... .. ... .... .... ..... ......... ..... 171 
Regulatory Comparison .. .... ...... ...... ........ .... ......... ... ..... .. ........ ....... .... ..... ..... ..... ....... .... ....... ... ... ......... ... ....... . 175 
Urban Forestry Mas ter Plan ..... ................. ....... ....... ... .. .... ................... ......... ....... ..... .... .... ........................... 207 
Executive Summary ..... ...... .... ... ... ......... .... .... ... .......... .... .... ........ ... ....... ... ..... .. ... ......... .. ....... .... ...... .. 215 
Implementation Matrix ........ ........ ............. .... .. ..... ........ ... .. .. .... ....... ..... ......... .... ........ .. ......... ..... ..... .. 216 
Basis for Decision Making 
Chapter 1: D evelopment Regulations and Mitigation Requirements 
Chapter 2: Landscaping Requirements 
Chapter 3: Tree Grove Protection 
Chapter 4: Hazard Trees 
223 
225 
227 
229 
233 
Chapter 5: Urban Forestry Program Management ... ... ................ ..... .. ...................... ................. . 235 
Chapter 6: Stewardship 
Glossary 
Appendix 
237 
243 
245 
O rganization ofthe U rban Forestry Cod e Revisions D ocuments 
The Urban Forestry Code Revisions project is presented in five volumes. Volume I provides the 
project overview and describes the process used to develop all of the elements. Volume II is the 
land use elements of the code, and Volume III the non land use elements. Volume IV contains the 
Urban Forestry Manual. Volume V contains technical reports and research that contributed to the 
code revisions along with details of the public input and deliberations to date. 
Volume I I Project Overview 
Project Overview includes the following sections: 
• Project Introduction 
• Overview of K ey E lements 
• Key Element Summaries 
o Urban Forestry Standards for D evelopment 
o Tree Grove Preservation Incentives 
o Tree Permit Requirements 
o H azard Trees 
o Urban Forestry Manual 
Appendix A includes additional detail about the information used to shape the Urban 
Forestry Code Revisions Project, and includes the following sections: 
• Process summary 
• Summary of Community Ideas and Concerns 
• Summary of Planning Commission D eliberations 
• Existing Conditions 
Volume II I Land Use Elements 
Community Development Code (Title 18) is the Planning Commission's recommended 
draft of the D evelopment Code. This section includes commentary on the amendments. 
Peer Review demonstrates how the Planning Commission's recommended draft of the 
D evelopment Code and Urban Forestry Manual will work in application. 
Tree Grove ESEE Analysis is a report that addresses Statewide Planning Goal 5 -Natural 
Resources requirements for the preservation of Significant Tree Groves. 
Staff Report and findings includes the staff recommendation for approval of the land use 
elements (Title 18 and the Comprehensive Plan Amendment) and the flndings that 
demonstrate the land use elements meet the necessary approval criteria. 
City of Tigard Urban Forestry Code ReYisions I Volume V I 1 
Volume III I N on L and Use Elem ents 
Tigard Municipal Code is the staff proposed draft of the Municipal Code (Title 8 and 
other Municipal Code titles). This section includes commentary on the amendments. 
Volume IV I U rban F ores try M anual (Administrative Rules) 
Urban Forestry M anual consists of administrative rules that implement the technical 
details of the urban forestry related code provisions in Title 8, Title 18 and other applicable 
titles in the Tigard Municipal Code. 
Volume V I Additional Background M aterials 
Planning Commission D eliberations details Planning Commission discussion and 
decisions during the public hearing process. 
Amendment Reques ts Document fo r the Planning Commission lists code amendment 
reques ts received in response to the first Planning Commission public hearing and staff 
responses. 
Outstanding Issues for the U rban Forestry Code Revisions includes additional 
information on the outstanding issues that were further deliberated by the Planning 
Commission before making their final recommendation to City Council on May 7, 2012. 
L og of Input lists the input received and any code changes from the las t meeting of the 
CAC to the sta ff proposed draft o f the Urban Forestry Code Revisions to Planning 
Commission. 
CAC Guiding Principles includes the consensus view of the Citizens Advisory Committee 
(CAC) developed to help guide the legislative adoption process. 
Tree Values includes information and current research on the environmental, economic, 
social and aes thetic benefits of trees. 
Canopy Standards explains the reasons for adopting tree canopy cover requirements as 
well as the methods used to arrive at the requirements. 
Soil volume details research about the soil volume required to support a mature tree 
canopy. 
Tree Canopy Fee discusses research used to develop a square foot value for tree canopy. 
Regula tory Comparison is an exce1vted report prepared by Metro and the Audubon 
Society that summarizes and compares regional urban forestry programs and regulations. 
U rban F orestry M aster Plan is the City of Tigard's recommended plan for achieving the 
urban forestry goals in the Comprehensive Plan. 
City o f Tigard Urban l;orcstry Code Rn ·isions I \ 'olumc \ ' I 2 
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To: 
From: 
Re : 
D ate: 
Introduction 
City ofTigard 
Memorandum 
City Council 
Todd Prager, Associate Planner/ Arborist 
Planning Commission D eliberations on the Urban Forestry Code Revisions 
May 16,2012 
T he Planning Commission held one workshop and four public hearings on the Staff Proposed 
Draft Urban Forestry Code Revisions from January 2012 through May 2012. Although they 
received a range of public testimony from a variety people during their public hearing process, 
the commission's deliberations focused on the 11 issues listed below. Each issue is listed in the 
form of question that framed the commission's deliberations. Also listed is the background 
information the commission used to inform their deliberations. Finally, the decision made on 
each issue is listed. 
T he comnuss1on decision on these issues, as well as a handful o f other non-substantive 
amendments to clarify code and correct errors, form the Planning Conunission Recommended 
Draft Urban Forestry Code Revisions. The Planning Commission Recommended Draft was 
unanimously approved by the Planning Commission at their May 7, 2012 meeting, and will be 
considered by City Council for adoption. 
Procedural Note 
Because of Oregon land use law, the land use elements of the proposal, such as the Tigard 
D evelopment Code (Title 18), Comprehensive Plan, ESEE Analysis and Significant Tree Grove 
Map are addressed separately from the non-land use elements, such as the Tigard Municipal 
Code (titles other than Title 18) and Urban Forestry Manual. 
In order to provide for a comprehensive approach to the Urban Forestry Code Revisions, the 
Planning Commission review and deliberations have included both the land use elements and 
non-land use elements o f the proposal. However, the Planning Commission's direct 
recommendation to City Council is Wnited to the land use elements o f the proposal. 
\t the same time, there are many aspects of the non-land use elements that are consistent with 
and supportive of the land use elements. The Planning Comtnission's recommendation to City 
City of Tigard Urban l'orcstry Couc Rc,·isions I \' olumc \ ' I 5 
Council states that the non-land elements of the proposal are consistent with and supportive of 
the land use elements. 
Planning Commission Issues and Decisions 
Issue 1, Why was tree canopy selected over tree count (i.e. tree density or number o f trees) as a 
requirement in the draft code? 
Background Information for Issue 1: During the Comprehensive Plan and Urban Forestry 
Master Plan processes, there was general consensus that the existing development code unfairly 
penalizes property owners with existing trees and encourages the overplanting of replacement 
trees. The reasoning was that mitigation requirements apply only to property owners with 
existing trees over 12-inch trunk diameter, and replacement trees or fees are required based on 
the diameter of trees removed. For example, if a 12-inch diameter tree is removed, replacement 
with 6, 2-inch diameter trees or a $1,500 fee in lieu o f replacement ($125/ inch fee) is required. 
Urban Forestry Master Plan Goal 1.2.a, recommends the city address this equity issue as part of 
the development code revisions by developing " . . . canopy cover or tree density requirements 
for all lots to be met by either preserving existing trees or planting new trees". The Urban 
Forestry Code Revisions Citizen Advisory Committee affirmed Urban Forestry Master Plan 
Goal 1.2.a by general consensus through surveys and group discussions, and staff has worked to 
draft corresponding development code revisions in the project record (see November 10, 2010 
pre-meeting survey and meeting minutes). 
When drafting the development code revisions, staff studied a tree density requirement 
(requiring X number of trees per square feet of development area) and compared it with a 
canopy requirement (requiring X square fee t o f canopy per square feet of development area). 
The canopy requirement was selected as the preferred alternative for the following reasons: 
• The canopy requirement allows more flexibility for the project designer to meet code 
requirements due to the wide variation o f canopy shapes by species. A tree density 
requirement presents the project designer with more limited options to meet numerical tree 
planting requirements. 
• The canopy requirement is more consistent with urban forest science and the city's long-
term urban forestry goals. The benefits o f trees (economic, environmental and social) are 
derived primarily from their canopies, rather than number of trees. The canopy requirement 
encourages large stature, appropriately spaced trees, which have the highest benefit/ cost 
ratios. A tree density requirement allows small stature, closely spaced trees to meet 
numerical requirements. 
• The canopy requirement requires the project designer to consider future canopy growth, 
which helps ensure that trees are properly placed within a site to become long-term 
amenities. T he canopy requirement encourages appropriate tree spacing and setbacks from 
Ciry of Tigard Urban l;orc> tn· Code Rc,·i>iom I \ 'olumc \ ' I (, 
buildings by highlighting mature canopy growth, whereas a density requirement focuses on 
planting a certain number o f trees and does not take mature growth into account. 
• The canopy requirement provides more consistency in development outcomes. For 
example, a parking lot planted to meet a numerical tree density requirement can look very 
different after future growth, depending on whether small ornamental trees or large shade 
trees are selected. The canopy requirement helps normalize outcomes. 
• Planting trees to meet either a canopy requirement or a tree density requirement both rely 
upon successful establishment and long-term maintenance by property owners. However, 
the canopy requirement focuses more on long-term growth during the initial design phase so 
that trees are more likely to become long-term site amenities. 
Commission Decision on Issue 1: The comnusston decided to retain the tree canopy 
requirement in the draft code because it is flexible, consistent with sound urban forestry 
practices, encourages thoughtful design and supports the community's long-term urban forestry 
goals. Therefore, no changes to the current proposal were made based on this issue. 
Issue 2, Will the tree canopy requirements result in a reasonable balance between trees, 
development and open space? 
Background Information for Issue 2: The Urban Forestry Code Revisions Citizen Advisory 
Committee reached consensus to draft achievable and balanced canopy requirements for 
development that are tiered, based on zoning district. For example, the development in low 
density residential areas is required to have more trees than in areas o f dense zoning, such as 
D owntown Tigard. 
To implement the consensus of the citizen advisory committee, staff analyzed possible percent 
canopy for each zoning district using the same methodology developed to set canopy goals for 
the Urban Forestry Master Plan and also in an updated methodology using Light D etection and 
Ranging (LiDAR) technology. 
The results o f the analyses were then used in conjunction with the nurumum percent 
landscaping requirements in the Tigard D evelopment Code to place the various zoning districts 
within one of three tiers. The exception is school sites, which were placed in the "dense 
zoning" tier 3 to ensure sufficient room for sports fields: 
Tier 1: 40% effective canopy 1 
Tier 2: 33% effective canopy2 
Tier 3: 25% effective canopy3 
1 R-1, R-2, R-3.5, R-4.5, R-7, and R-12 
2 R-25, R-40, C-N, C-C, C-G, C-P, i\nJE, i\fUE-1, MUE-2, 1IUC, MUR, and 1-P 
3 i\fU-CBD, i\nJC-1, 1-L, 1-H, and schools (18.130.0500)) 
City of Tigard Urban Forestry Code Rc1·isions I Volume V I 7 
It is important to note that if./edive mnopy is very different from actual mnopy within the lot lines of 
a particular development. To meet draft effective canopy requirements, the preservation o f 
existing trees is granted double canopy credit and planting o f street trees is granted full canopy 
credit even though half of their canopies overhang streets, which are no t part of the calculations. 
When considering these fac tors, the actual canopy required for a particular development would 
fa ll into the following ranges: 
Tier 1: 16-40% actual canopy 
Tier 2: 13-33% actual canopy 
Tier 3: 10-25% actual canopy 
The low end o f each range represents sites with many ex1sung trees that are preserved and 
maximization of street tree canopy. T he high end of each range represents sites with no existing 
trees and no street tree canopy (all trees planted so the mature canopy stays within the lot lines). 
T he possible percent canopy for each zoning distric t falls within the actual canopy range for 
their corresponding tiers above. 
T he double canopy credit for presen ration provides a viable option for meeting canopy 
requirements in the draft code while incentivizing preservation. T his is because buildable lands 
have significant existing tree resources from which to draw. Staff performed a GIS analysis o f 
the city's buildable lands inventory and determined that buildable lands have an average o f 41 
percent existing canopy cover (see Urban Forestry Code Revisions Citizen Advisory Committee 
April 13, 2011 meeting packet, pages 45 to 46 in the project record). 
In many cases, development (and tree removal) is restricted on a portion o f a development site 
due to existing sensitive lands protections (for wetlands, streams, floodplains, etc.). Staff 
performed a G IS analysis of existing canopy that is protected on buildable lands due to its 
location in protected sensitive lands. T he analysis demonstrated that an average of 12.29 percent 
o f canopy on buildable lands would be preserved due to its location in sensitive lands. 
T herefore, because of double credit for preservation, development on buildable lands would 
achieve an average of 24.58 percent effective canopy through the presen ration of trees that are 
already required to be presen red (see Urban Forestry Code Revisions Citizen Advisory 
Committee April 13, 2011 meeting packet, pages 45 to 46 in tl1e project record). 
Staff and outside consultants tested the tiered requirements on a wide range o f development 
pro jects to ensure the draft effective canopy requirements are achievable, result in a reasonable 
balance between trees and development, and do no t force payment o f fees in lieu or 
discretionary review for typical projects. 
T he peer review demonstra tes that the requirements are achievable without payment of fees in 
lieu or discretionary reviews. 
CitY of Tiganl Urban l'orcstry Cock Rc,·isions I \ 'o lume \ ' I H 
Staff advised the commission that the draft effective tree canopy requirements would result in a 
reasonable balance between trees, development and open space. However, in the discussion of 
Issue 3 below, staff included an option for the commission to reduce tree canopy to the 
following ranges by granting bonus credits for native trees: 
Tier 1: 16-32% actual canopy 
Tier 2: 13-26% actual canopy 
Tier 3: 10-20% actual canopy 
Staff also provided an option for the commission to reduce tree canopy by reducing and/ or 
eliminating the per lot minimum. The background information for Issue 4 below, describes how 
reducing and/ or eliminating the per lot tree canopy requirement would have the effect of 
reducing the tree canopy requirement for the overall development site. 
Commission Decision on Issue 2: The commission decided that in most cases the tree 
canopy requirements provide a reasonable balance between trees, development and open space. 
However, to be conservative, the commission moved the R-12 district into the Tier 2 category. 
This was because the R -12 district was not tested as part of the peer review phase, and higher 
density residential districts (R-25 and R-40) were able to meet the Tier 2 requirements. 
In addition, as further explained in Issue 3, the commission selected the option to effectively 
lower the tree canopy requirements by 20 percent for projects that use native trees: 
Tree Canopy Requirements Tree Canopy Requirements 
without Native Trees with Native Trees 
Tier 1: 16-40% actual canopy Tier 1: 16-32% actual canopy 
Tier 2: 13-33% actual canopy Tier 2: 13-26% actual canopy 
Tier 3: 10-25% actual canopy Tier 3: 10-20% actual canopy 
Finally, the commission decided to reduce the per lot minimum from 20 percent down to 15 
percent for Tier 1 sites, and to eliminate the per lot minimum for Tier 2 and 3 sites. These 
decisions further reduces the tree canopy requirements for the overall development sites as 
further explained in the background information for Issue 4. 
Issue 3, Will the tree canopy requirements favor lower quality trees (i.e. fast growing, non-
native deciduous)? 
Background Information for Issue 3: The peer review noted that the draft code could result 
in the unintended consequence of shifting Tigard's tree population to broad spreading 
deciduous trees. The rationale is that applicants will naturally plant broad spreading deciduous 
trees, rather than more narrow growing evergreens as the most cost effective method to meet 
tree canopy requirements in the draft code. The rate of growth (i.e. fast growing vs. slow 
growing) has not been noted as a factor in decision-making because the draft code grants tree 
canopy credit based on mature size, regardless o f how long it takes to achieve that size. 
Cit}' o f Tigard Urban 1:orcstry Code Rc,·isions I Volume \' I 9 
Staff does not disagree that overreliance on broad spreading deciduous trees is a po tential 
unintended consequence o f the code. Since there are more non-native trees than native trees on 
the recommended tree lists, there is also the potential for overreliance on non-native trees to 
meet tree canopy requirements. 
It is important to note the draft code requires that collection o f spatial and species-specific 
information on required trees be included in the city's urban forest inventory. T his data will 
allow the city to periodically evaluate whether there is an overreliance on particular species, 
because o f the draft code. 
In addition, Clean Water Services requires preservation and planting o f native trees in vegetated 
corridors, which comprise over 9 percent o f land area citywide. Also, the tree grove preservation 
incentives pertain to large groves of native trees and are intended to facilitate their preservation. 
Native trees that result from Clean Water Services requirements and tree grove preservation 
incentives are eligible for credit towards the draft tree canopy requirements and could help 
balance the ratio between native, non-native, deciduous and evergreen trees. 
When surveyed on the issue, the citizen advisory committee consensus was for city to allow the 
project designer to select a mix o f native and non-native trees, depending on site conditions (see 
November 10, 2010, pre-meeting survey in the project record). A strong preference for native 
trees did not emerge as part o f their discussions. 
H owever, staff understands the planning commission is interested in exploring the potential to 
increase the relative am ount o f native to non-native trees. One option could be granting bonus 
tree canopy credit for the planting o f native trees. Staff suggests consideration be given to 1.25 
times the m aturity canopy spread o f trees on the native tree list. Since the native tree list 
includes several broad spreading evergreens (e.g. grand fir, D ouglas fir, and western hemlock) 
this could also increase the relative amount of evergreen to deciduous trees. 
Finally, staff understands the planning commission is interested in exploring ways to reduce the 
tree canopy requirements to allow for more open space and development. G ranting 1.25 canopy 
credit for native trees would reduce the canopy ranges for development that relies solely on 
native trees as follows: 
Tree Canopy Requirements Tree Canopy Requirements 
without N ative Trees with Native Trees 
Tier 1: 16-40% actual canopy Tier 1: 16-32% actual canopy 
Tier 2: 13-33% actual canopy Tier 2: 13-26% actual canopy 
Tier 3: 10-25% actual canopy Tier 3: 10-20% actual canopy 
Commission D ecision on Issue 3: T he commission decided to grant 1.25 bonus credits to 
encourage the planting o f native trees. As explained in Issue 2, this effectively lowers the tree 
canopy requirements by 20 percent for projects that use native trees. 
Ci tY of T igard Urban l'orc>try Code Rc,·i> iom I \ 'olumc \ ' I ]II 
Issue 4, Should tree canopy be measured across the overall development site only rather than 
on a lot by lot basis? 
Background Information for Issue 4: Early in the process, staff initially proposed the tiered 
tree canopy requirements to be met on a lot by lot basis in addition to the overall development 
site. The Urban Forestry Code Revisions Citizen Advisory Committee recommended allowing 
averaging of canopy across the overall development site while setting a minimum per lot tree 
canopy requirement. Staff proposed a 20 percent minimum per lot requirement at the April 13, 
2011, meeting and the committee approved the proposal by consensus (see minutes in the 
project record). The rationale for having a minimum per lot tree canopy requirement is to 
spread the distribution of trees, and therefore tree benefits and maintenance responsibilities, 
more evenly across a development site. 
Staff advised the commission that reducing or eliminating the per lot tree canopy requirement 
would likely not raise major issues since it was not a major part of the deliberations when 
developing the proposal. Street tree requirements would still apply and support an evening of 
the distribution of trees across the development site, even if the per lot tree canopy 
requirements were reduced or eliminated. Finally, the peer review results show that while the 
tree canopy requirement for the overall development site is met, often small stature additional 
trees are required in residential backyards to meet the per lot minimum tree canopy requirement. 
Therefore, if the per lot tree canopy requirement were reduced or eliminated, the effective tree 
canopy requirement for the overall development site would be reduced. 
Commission Decision on Issue 4: The commission decided to reduce the per lot minimum to 
15 percent for Tier 1 districts Qower density residential development), and to eliminate the per 
lot minimum requirement for the Tier 2 and 3 districts (higher density residential, commercial, 
mixed use, industrial, and school development). 
The decision to reduce the per lot minimum to 15 percent for Tier 1 districts was based on staff 
analysis that for most lots, 15 percent tree canopy could be provided by planting one large 
stature street tree, thereby eliminating the need to plant an additional small stature tree which 
provide limited benefits in residential backyards. 
The decision to eliminate the per lot minimum for Tier 2 and 3 districts was two-fold. First, due 
to the more limited street frontage of higher density residential lots, it is more difficult to place 
street trees for each lot to meet the per lot minimum. Eliminating the per lot minimum for 
higher density residential lots increases flexibility by allowing the project designer to focus on 
meeting tree canopy requirements for the overall development site. Second, their decision to 
eliminate the per lot minimum for commercial, mixed use, industrial and school development 
was because these sites are often a consolidation of unique lots that could present challenges 
when meeting the requirements on a lot by lot basis. 
City o f Tigard Urban Forestry Code Re,·isions I Volume V I 11 
Issue 5, Should there be minimum preservation requirements? 
Background Information for Issue 5: Consistent with the direction o f the Urban Fores try 
Code Revisions Citizen Advisory Committee majority at their November 10, 2010, meeting (see 
minutes in the project record), staff drafted code that did no t require a base level o f 
preservation. At the citizens advisory committee meeting on April 13, 2011 , eight were in favor 
and one was opposed to the draft requirements, which included tiered tree canopy targe ts based 
on zoning, no base level of preservation and bonus credits to incentivize preservation (see 
minutes in the project record). 
T he rationale o f the committee for no t requiring a minimum level o f preservation include no t 
unfairly penalizing property owners with trees, allowing flexibility for removing trees that may 
not be viable or desirable and no t limiting infill development. T he consensus supported 
preservation incentives that actually reward landowners with existing trees (see November 10, 
2010, meeting minutes in the project record). 
It is important to note that the proposed incentive based approach, with no nummum 
preservation requirement, has already led to additional preservation in one high profile scenario. 
In the summer of 2011 , a property owner at Hunziker and Wall Street voluntarily chose to 
preserve six acres o f existing trees to meet the draft code requirements rather than removing 
essentially all trees as originally planned. This property owner was aware of the double credit for 
preservation and made his preservation decision to avoid planting 12 acres o f new trees required 
by the draft code. 
If minimum preserva tion requirements are desired in the draft code, staff would recommend a 
preservation percentage rather than number to limit variability between properties of different 
sizes. Also, staff would recommend investiga tion of a tree removal permit process to limit 
predevelopment clearing, which is a method used to avoid tree preservation requirements in 
development codes. Such a tree removal permit process could be limited to trees on the city's 
buildable lands inventory. H owever, the message to the conununity thus far has been that tree 
removal permits are not proposed to be required in additional situations. Requiring tree removal 
permits in additional situations has the po tential to result in significant concerns in the 
community. 
Commission D ecision on Issue 5: T he comnuss10n decided no t to include nummum 
preservation requirements because it would not be consistent with community expectations o f 
an equitable, flexible and incentive based code. T herefore, no changes to the current proposal 
were made based on this issue. 
Issue 6, H ow will tree / utility conflicts be limited? 
Background Information for Issue 6: The Urban Fores try Plan requirements specify that 
utilities are to be shown on the plan so conflicts with trees can be easily identified and corrected. 
The existing code allows utilities and trees to be shown on separate plan sheets, which makes it 
CitY of T igard Urban l;orcstry Code RLTisions I \ 'olumc \ ' I 12 
difficult to identify conflicts. Staff coordinated with Portland General Electric to include trees in 
the Urban Forestry Manual that are allowed / required for planting under overhead power lines. 
In addition, public works staff on the Technical Advisory Committee identified setback 
requirements for street trees from public utilities to limit conflicts. 
Commission Decision on Issue 6: The commission decided the current proposal will limit 
tree and utility conflicts. Therefore, no changes to the current proposal were made based on this 
Issue. 
Issue 7, How will hazard trees on adjacent properties be addressed? 
Background Information for Issue 7: Chapter 8.08 would prohibit hazard trees in Tigard. If a 
tree on an adjacent property is a hazard, Chapter 8.08 would allow people to file a claim with the 
city. The city would then utilize a third party arborist to evaluate the tree. If the arborist 
determines there is a hazard, abatement would be required. The city could enter a property, 
abate a hazard tree, and recover costs in cases where an owner is uncooperative after obtaining a 
warrant. The city could abate tree hazards without a warrant when there is an imminent threat to 
public health or safety. 
Commission Decision on Issue 7: The commission decided the current proposal adequately 
addresses hazard trees. Therefore, no changes to the current proposal were made based on this 
Issue. 
Issue 8, Will significant tree groves result in reduced property values for properties with groves? 
Background Information for Issue 8: The tree grove preservation incentives are voluntary 
and provide flexible incentives to facilitate preservation. Applicants are not required to utilize 
the flexible incentives and may develop their properties as if there were no significant tree grove. 
Therefore, staff thinks properties with significant tree groves will not have reduced property 
values. 
Commission Decision on Issue 8: The comm1ssion decided that since the tree grove 
preservation incentives are voluntary, the presence of tree groves will not reduce property 
values. Therefore, no changes to the current proposal were made based on this issue. 
Issue 9, Is the tree canopy fee fair and reasonable, and will the tree canopy fee be updated as 
the PNW-ISA updates the wholesale cost of trees in the Willamette Valley? 
Background Information for Issue 9: The methodology for the proposed tree canopy fee was 
developed by converting the wholesale median tree cost in the Willamette Valley, developed by 
the PNWISA, to a unit canopy cost. According to the PNWISA, the median wholesale cost of a 
3-inch diameter deciduous tree is $17 4. The formula developed by Krajicek, et al. for open 
grown, broad spreading trees (maximum crown width (feet) = 3.183+1.829*DBH (inches)) was 
then utilized to convert tree diameter to canopy diameter. According to the Krajicek formula, a 
City o f Tigard Urban Fores try Code Rc,-isions I Volume V I 13 
3-inch diameter tree should have a crown width of 8.67 feet or crown area of 59 square feet. 
T hese dimensions were confirmed as reasonable by staff through several local field samples. 
Using the median cost of a 3-inch deciduous tree ($174) and the crown area of a 3-inch diameter 
tree (59 square feet), the unit canopy cost or tree canopy fee should be $2.95 per square foo t. 
Staff advised the commission that this methodology is a fair and reasonable approach for three 
main reasons. First, tree benefits (aesthetic, storm water management, air quality, etc.) are 
derived primarily from their canopies, so proposing to place a value to tree canopy is 
appropriate. Second, in the proposal, tree canopy is valued using the median wholesale tree cost 
only, whereas requirement tree appraisal is based on the wholesale tree cost, plus the cost o f tree 
installation. Finally, the Krajicek formula and field samples by staff are based on the maximum 
crown width-to-trunk diameter ratio. A typical tree does no t have such a high ratio. If the 
typical ratio were used, the unit canopy cost would increase. 
As explained in the "Comparative Fee-in-Lieu Rates" memo from the February 6, 2012 
Planning Commission meeting (table excerpted below), the proposed tree canopy fee in lieu 
would be low when compared with other fees in the region: 
Cin· o f Tigard Urban l;orcsLry Code Rc,·isions I \ 'olume \ ' I 14 
' 
City Fee Fee Per Context 
Caliper 
Inch* 
City of Tigard $125 per $125 Based on average cost to purchase, 
(existing) caliper inch install, and maintain a two-inch caliper 
replacement tree. 
City ofTigard $2.95 per $87 Based on the median wholesale cost o f a 
(proposed) square foot of three-inch deciduous tree in the 
canopy Willamette Valley ($17 4). 
Beaverton $90 coniferous $45 conifer Costs are based on the purchase and 
$17 5 deciduous $87.50 decid. planting of two-inch caliper trees to 
$200 street tree $100 st. tree mitigate for loss of Significant 
Trees/ Groves on a 1:1 basis. 
Gresham n/a n / a No established fee in lieu program per 
planner on du_ty. 
Hillsboro n / a n/ a No established fee in lieu program per 
planner on du_!y. 
Lake Oswego $328 per $164 Code strongly emphasizes protection 
mitigation tree over miti_gation. 
Oregon City $290 per $145 Fee in-lieu of replacement tree standards 
mitigation tree of two-inch caliper deciduous or six-foot 
high conifers. 
Portland $300 per $300 Applies to all trees regulated under 
caliper inch Portland Code. 
Tualatin n/ a n / a No established fee in lieu program per 
planner on duty. 
West Linn $175 per street $87.50 Mitigation fees not required. Applicants 
tree can pay the City $17 5 to install street 
trees, or $7 5 to inspect developer-
installed trees. 
Wilsonville Market Price Market Price Applications must include the actual cost 
of the required replacement trees 
(generally 1:1), with documented bids 
included with application materials. Per 
planner on duty. 
Vancouver, Market Price Market Price Fee in lieu rates based on estimated 
WA market cost to purchase, install and 
maintain required tree units (based upon 
DBH). Applicant submits documented 
bid with application materials. 
*Fee per caliper im:h column i.r an approximate convenion i?J City if Tigard .rtqff to e.rtabli.rh a common unit for 
mmpari.ron. 
City of Tigard Urban Forestry Code Re\'isions I Volume\ ' I 15 
Also, the tree canopy fee in lieu in the proposed code is lower than the mitigation fee in lieu in 
the existing code: 
Existing Tigard Code Proposed Tigard Code I 
Mitigation Based Canopy Based I 
$125/ caliper inch $2.95 / sq. ft. 
Fee for 12" DBH Tree = $1,500 Fee for 12" DBH Tree = $1,4634 
T he comm1ss1on asked whether the city is interested in po tentially increasing revenue by 
lowering the fee in lieu (so applicants pay the city rather than plant or preserve trees with 
development). Staff advised the commission that the purpose o f the fee is to create an incentive 
to plant and preserve trees on private property, rather than to crea te a revenue source for the 
city. T his is consistent with the direction o f the citizen advisory committee. 
To the second part o f Issue 9 for updating the tree canopy fee, the tree canopy fee is based on 
the "most recent wholesale median tree cost established by the PNW-ISA" T herefore, as the 
PNW-ISA updates their cos ts, the tree canopy fee would be updated as well. 
Commission Decision on Issue 9: T he commission decided the proposed tree canopy fee is 
fair and reasonable because it is a conservative appraisal o f tree canopy, based on industry 
standard methodologies. T he fee is low when compared with o ther fees in the region, and is less 
than the mitigation fee in the existing code. 
T he commission also decided the tree canopy will be updated as the PNW-ISA updates the 
wholesale cost of trees in the Willamette Valley. T herefore, no changes to the current proposal 
were made based on this issue. 
Issue 10, Should the city establish a pro tocol for pro tected tree and tree grove information to 
be filed with the city and/ or county so that information will readily available during title 
research when purchasing a property? 
Background Information for Issue 10: At the November 10, 2010, meeting, the Urban 
Fores try Code Revisions Citizen Advisory Committee consensus was to not require the filing o f 
deed restrictions for preserved and planted trees (see minutes in the pro ject record). T heir 
rationale was that deed restrictions are ineffective methods for noti fying people of protected 
trees and that requiring deed restrictions places excessive burdens on applicants and future 
owners. 
In response to the committee consensus, staff included code language requiring the recording of 
in formation on protected trees in the city's publicly accessible G IS system. T his would allow the 
public to retrieve in formation on pro tected trees from their home computers. T his ability to 
1 DBI-I converted to canopy using the Krajicek formula 
CitY of Tigard Urban For~stry Code R~Y i sions I \'olumc \ ' I ](, 
retrieve information would work in concert with the existing city program of sending mailings to 
new property owners on a quarterly basis to inform them of the city's urban forestry program 
and regulations. 
The commission requested input from the City Attorney regarding the legal requirements for 
property owners to maintain trees that were planted by developers during the two-year 
establishment period. The concern raised by the commission was whether property owners 
could remove trees that were planted by developers. 
Section 6.02.180 (Property Development and Maintenance Requirements, Urban Forestry) 
would prohibit the unauthorized removal of trees during the two-year establishment period. If a 
property owner were to remove a tree, they would be subject to penalties in Chapter 1.16 (Civil 
Infractions). In addition, the City Attorney advised that the developer could contractually 
obligate a property owner to maintain or allow for the maintenance of trees as part of the 
purchase and sale agreement. This would provide added assurance that trees would not be 
removed during the establishment period. 
Commission Decision on Issue 10: The commission decided that existing regulatory and non-
regulatory requirements will help ensure property purchasers are aware of tree requirements for 
a particular property. Therefore, no changes to the current proposal were made based on this 
1ssue. 
Issue 11, Is the cost of developing urban forestry plans for higher density residential 
development excessive since the peer review results show the requirements can be met through 
strategic planting of large stature street trees? Is the cost of developing urban forestry plans for 
Minor Land Partitions (2 and 3 lot residential developments) excessive since there is less profit 
associated with these types of developments? 
Background Information for Issue 11: For part one of Issue 11, the peer review results do 
demonstrate that for high density residential sites, the effective tree canopy requirements can be 
met primarily through strategic planting of large stature street trees. 
The incentive to maximize street tree canopy is deliberate as street trees are scientifically proven 
to have particularly high benefit to cost ratios in urban areas. Street trees are increasingly viewed 
as part of the city's "green infrastructure", as essential as other infrastructure elements, such as 
street lights and storm drains. However, for street trees to achieve their potential canopy 
growth, adequate soil resources and proper planting methods are critical. 
The proposed code places a high value on the role of arborists in designing and implementing 
the conditions for sustainable urban tree canopy, which include providing adequate soil 
volumes. In some cases, a landscape architect is required if alternative techniques are utilized, 
such as structural soil volumes under pavement. For general tree planting on sites, the project 
arborist is required to evaluate soils and recommend amendments if needed to support tree 
growth. The project arborist is also responsible for specifying and monitoring the tree 
City of Tiga rd Urban Forestry Code Re,·isions I Volume V I 17 
protection fencing for trees to be preserved, which include neighboring trees close to the 
property lines. 
Staff acknowledges that requiring arborists adds cost to projects, but it is consistent with the 
direction o f the Urban Forestry Code Revisions: to distribute development costs more equitably 
(rather than only requiring arborists for projects with existing trees) and to focus on establishing 
healthy future canopy (rather than only penalties for tree removal). 
For part two of Issue 11 , plans developed by a certified arborist for the preservation and 
planting of trees is already required for Minor Land Partitions by the existing code. The 
proposed code would continue to require plans developed by a certified arborist for Minor Land 
Partitions. An analysis o f the buildable lands inventory found that the largest share of buildable 
sites in Tigard is between 10,000 sq. ft. and 1 acre. This means that Minor Land Partitions likely 
represent a significant share of future residential development in Tigard. 
The cost estimated by staff to develop and implement an urban forestry plan for a Minor Land 
Partition based on interviews with local arborists is between $4,000 and $5,000 (includes 
inventory field work, site plan, arborist report, revisions based on city review, and 
implementation inspections). H owever, costs associated with the existing code for tree removal 
mitiga tion can reach $30,000 for a Minor Land Partition (this is in addition to the cost of 
developing a tree plan). 
During the background research for Issue 11 , staff did identify an opportunity for creating 
efficiencies when developing urban forestry plans, while ensuring high quality design and 
implementation. The code requires arborists to develop urban forestry plans (which involve 
developing a tree inventory, protection and planting plan). H owever, the code also requires a 
landscape architect when alternative methods such as structural soils are used to meet soil 
volume requirements. This is because landscape architects have more expertise structural soils. 
For pro jects that use structural soils to meet their requirements, it would reduce costs if the 
landscape architect could also complete the Urban Forestry Plan (without requiring a certified 
arborist) since landscape architects also have the skill set needed to inventory, protect and plan 
trees. 
Commission Decision on Issue 11: T he commission decided that the costs for developing 
urban forestry plans were not excessive for higher density residential development and Minor 
Land Partitions. T his is because the existing code requires arborists for these development types 
to create tree plans. In addition, since mitigation is proposed to be eliminated, costs will likely 
decrease, particularly for those projects with existing mature trees. T he commission decided it is 
consistent with the direction of the Urban Forestry Code Revisions: to distribute development 
costs more equitably (rather than only requiring arborists for projects with existing trees) and to 
focus on establishing healthy future canopy (rather than only penalties for tree removal). 
CitY of TigarJ Urban l ;or~str r CoJ e Rn ·isiom I \ 'olumc \ ' I IH 
However, the commission did decide to allow landscape architects, in addition to arborists, to 
develop urban forestry plans to reduce costs by eliminating the need for l1iring two urban 
forestry professionals. 
City of Tiga rd Urban l'orestry Code ReYisions I Volume V I 19 

Urban Forestry Code Revisions 
Amendment Requests Document 
for the Planning Commission 
City of Tigard Urban Fore~ try Code Rc,,i ~ i ons I Volume V I 21 
('] 
('] 
T o: 
From: 
Re: 
D ate: 
City ofTigard 
Memorandum 
City Council 
John Floyd, Associate Planner and Todd Prager, Associate Planner/ Arborist 
Amendment Requests Document for Planning Commission 
June 25, 2012 
The flrst Planning Commission hearing for the Urban Forestry Code Revisions (UFCR) on 
February 6, 2012 generated 85 amendment requests. These amendment requests were 
considered by Planning Commission and were used to help focus their discussion on the 
issues of primary concern. 
Amendment requests are listed in chronological order, by date received. Each request is 
documented with the following: 
~ Number of the request. 
~ Name of the requester(s). 
~ Date(s) of the request. 
~ A generalized statement of the request(s). In cases of short or speciflc requests, staff 
has quoted direcdy from testimony received. In both cases staff drew from the oral 
testimony at the February 6, 2012 public hearing and written testimony presented to 
the Planning Commission. 
~ Staff comment. 
~ Staff recommendation. 
~ Recommended amendment language. 
In cases where the requester made the same request multiple times, or where two or more 
parties commented on the same issue, staff combined them into one entry for purposes of 
efficiency. Thematic variations or opposing requests are noted in each entry. Staff 
responses are proportional to the specificity and complexity of the amendment request. 
Based on the amendment requests received, staff recommended the Planning Commission 
amend to the staff proposed UFCR in six places listed below by amendment number. See 
the full request, response and recommendation for complete information: 
~ Amendment 11: Minor text amendment to the summary heading of section 
18. 790.030.A 
~ Amendment 16: Grant 1.25x bonus credit for planting native trees 
City of Tigard Urban Fores try Code Rc1·isions I Volume \' I 23 
>- Amendment 36: Reduce the per lot effective tree canopy requirement to 15% 
>- Amendment 37: Correct scrivener's error in section 18.790.030.C 
>- Amendment 41: Minor text amendment to remove a repetitive approval criterion for 
tree removal permit requirements in sensitive lands 
>- I\mendment 72: Correct scrivener's error in ESEE and correct boundaries o f 
significant tree groves #38 and #62 to reflect changes due to recent tree removal 
A fter receiving public testimony and comments on the above changes, the Planning 
Commission considered the fo llowing additional amendments: 
>- Move the R-12 Zone into Tier 2 
>- Eliminate the 15% per lot minimum for Tier 2 and 3 districts 
>- Allow landscape architects, in addition to arborists, to develop urban forestry plans 
T he Planning Commission approved the amendments in both o f the lists above at their May 
7, 2012 meeting. T he memo, which immediately follows this memo, titled "Outstanding 
Issues for the Urban Forestry Code Revisions" describes the options that were considered 
by Planning Commission before reaching their final decision. 
Key to Acronyms used in this document: 
>- CAC: Citizen Advisory Committee 
>- COT: City of Tigard 
>- CWS: Clean \Vater Services 
>- DBH: Diameter at Breast H eight 
>- DLCD : D epartment of Land Conservation and D evelopment 
>- ESEE: Economic, Social, E nvironmental and E nergy [elaborate?] 
>- G IS: Geographic Information System 
>- LUBA: Land Use Board of Appeals 
>- ODFW: O regon D epartment of Fish and Wildlife 
>- OAR: Oregon Administrative Rules 
>- O RS: O regon Revised Statue 
>- SD C: Systems D evelopment Charge 
>- TD C: Tigard D evelopment Code 
>- TMC: Tigard Municipal Code 
>- UFCR: Urban Forestry Code Revisions Project 
>- UFM: Urban Forestry Manual 
>- UFP: Urban Forestry Plan 
>- USDA: United States D epartment of Agriculture 
1\ll references to project materials in the fo llowing are to the volumes considered by the 
Planning Commission, not to the volumes under consideration by the City Council. 
City o iTigard Llrban l'o re> try Code RcY i>iom I \ 'olumc \ ' J 14 
1. Steve Martin, January 11, 2012 
Amendment Request: Increase allowed residential density in the MUE zone or remove 
limitations like the MUE-1 zone to make retaining tree groves economically meaningful. 
Staff Response: The state's Transportation Planning Rule requires a city proposing a zone 
change to perform a traffic impact analysis. Allowing additional units is a zone change and 
the city does not have the budget or time to complete a traffic impact analysis as part of the 
UFCR project. 
The MUE zone is located in the Tigard Triangle and it is a goal of the city to increase density 
and spur development in this area. Currently, a high capacity land use study is being 
finalized and a Tigard Triangle plan is in its beginning stage. Both processes are looking at 
potential changes to the Tigard Development Code and zoning that would make the Tigard 
Triangle more attractive to developers and a location for increased density. The high capacity 
land use study and Tigard Triangle plan are more appropriate venues for discussing revising 
MUE regulations to facilitate the preservation of significant tree groves. 
Staff Recommendation: D o not revise proposed code based on this amendment request. 
Amendment: N I A 
2. Steve Martin, January 11, 2012 
Amendment Request: Building height restrictions in the MUE zone need to be increased 
or removed to allow increased density. If a maximum height must be set, then it should be 
at least 85 feet. 
Staff Response: The CAC consensus recommendation was to allow increased building 
height for commercial and industrial developments to facilitate the preservation of 
significant tree groves (see UFCR Volume I, page 17). However, the CAC also 
recommended protecting surrounding development from impacts associated with 
excessively tall buildings. 
The Tigard Building Division advised 20 additional feet of height is needed to accommodate , 
additional floor for commercial and industrial buildings. The CAC supported the staff propos 
of allowing 20 additional feet of building height as a compromise between providing a 
meaningful tree grove preservation incentive while not allowing excessively tall buildings (see 
Section 18.790.050.D.3 and .4, page 323 ofVolume II) 
If additional building height is desired in the MUE zone to allow increased density, staff 
recommends further analysis through the high capacity land use study and Tigard Triangle 
planning processes, for the reasons outlined in the previous staff response. 
Staff Recommendation: Do not revise proposed code based on this amendment request. 
Amendment: N I A 
--- ----- ----
City of Tigard Urban Forestry Code Re,·isions I \' olumc \ ' I 25 
3. Steve Martin, January 11, 2012 
Amendment Request: Increase the reduction in required canopy coverage or give 
administrator greater flexibility to reduce. 
Staff Response: The preservation of significant tree grove canopy would also receive 
double credit for preservation towards the effective tree canopy requirements. In addition, if 
50% of a significant tree grove is preserved the "per lot" effective tree canopy requirement 
would be waived (see Section 18.790.050.D.5, UFCR, Vol. II, p. 325). T he CAC did no t 
recommend further reducing effective tree canopy requirements for the preservation of 
significant tree groves (UFCR, Vol. ,I, p.17). 
Staff Recommendation: D o not revise proposed code based on this amendment request. 
Amendment: N I A 
4. Steve Martin, January 11,2012 
Amendment Request: Allow rooftop tree canopy coverage to count toward required tree 
canopy coverage. 
Staff Response: Trees planted on rooftops would be granted credit toward effective canopy 
requirements provided the project arborist determines the planting design is viable in the 
supplemental arborist report (see UFCR, Volume II, page. 390). 
Staff Recommendation: D o not revise proposed code based on this amendment request. 
Amendment: N I A 
5. Steve Martin, January 11, 2012 
Amendment Request: Remove as much uncertainty as to density, height restrictions, 
setbacks and required canopy as possible. 
Staff Response: The flexible standards and incentives for the preservation o f significant tree 
groves in Section 18.790.050.D are clear and objective standards that provide certain ty for 
applicants. A significant tree grove map will be maintained by the director to identify the 
location and size of significant tree groves. T he eligibility requirements for the flexible 
standards and incentives are based on square footage and percent preservation of significant 
tree groves. Flexibility on density, height setbacks, and required canopy are also based on 
numerical standards that can be calculated during land use review. 
Staff Recommendation: D o not revise proposed code based on this amendment request. 
Amendment: N I A 
City of 'J'igarJ Urban l•'orcstry Code Rc,·isions I \ 'o lun1e \ ' I 2() 
6. John Frewing, January 12, 2012 
Amendment Request: The canopy target approach should not be used because it is novel 
to the United States. 
Staff Response: The canopy target approach in the draft code is not novel in the United 
States. Many cities and counties throughout the country, particularly in the southeastern 
United States, have adopted tree canopy ordinances. The list includes, but is not limited to: 
~ Louisville, Kentucky. 
~ Chapel Hill, North Carolina. 
~ Athens-Clark County, Georgia. 
~ San Antonio, Texas. 
~ Many cities/ counties in Virginia as result of state enabling legislation adopted in 
1989. 
~ Sherwood, Oregon [In the process of adoption, public hearing before City Council 
scheduled for March 20]. 
In 2003 the USDA Forest Service completed a white paper1 describing and comparing 
ordinances based on the mature canopy growth of trees from sample cities in the 
southeastern United States. 
While tree canopy ordinances are well established in the United States, it is recommended to 
tailor ordinance provisions to the local community to ensure broad based support during 
implementation. This has been a priority during the UFCR, as evidenced through the 
enhanced public engagement efforts throughout the project (see Process Summary, UFCR 
Volume I, page 17). 
Staff Recommendation: Do not revise proposed code based on this amendment request. 
Amendment: N /A 
1 Hartel, Dudley R. 2003. Tree Canopy Ordin ances. Athens, GA: Southern Center for Urban Forestry Research and 
Information, USD.-\ Forest Service. ,-\ccessed via the World Wide Web 
< http: //www.urbanforestr.ysouth.org / resources / library / tree-canopy-ordinances / ft!e > on January 17, 2012. 
City of Tigard Urban l'orcstry Code Rc,·isions I \'olumc V I 27 
?.John Frewing,January 12,2012 (written), February 6, 2012 (oral), and February 17,2012 
(written); O pposed by Ken Gertz, February 17, 2012 
Amendment Request: Frewing: "require a calculated percentage o f existing trees on the 
development impact area o f a site to remain as a condition of approval." 
Gertz: " It is counterproductive and causes more trees to be cut than saved." 
Staff Response: Consistent with the direction o f the CAC majority, staff drafted code that 
did no t require a base level o f preserva tion but instead gave bonus credits toward meeting 
canopy targets to incentivize preservation. T he rationale o f the committee for not requiring a 
minimum level of preservation included no t un fairly penalizing property owners with trees, 
allowing flexibility for removing trees that may not be viable or desirable and no t limiting 
infill development (see November 10, 2010 meeting minutes in the project record). 
A t the April 13, 2011 meeting, the eight o f nine CAC members present voted to approve the 
draft standards, which did not require a base level o f preservation. 
In response to public tes timony received on the issue, planning commission further 
discussed whether to require a base level o f preservation at their March 5, 2012, meeting. 
T he commission indicated their support for the CAC recommendation and did no t direct 
staff to include a base level of preservation in the draft code. 
Staff Recommendation: D o not revise proposed code based on this amendment request. 
Amendment: N I A 
Cin· or Tigard Urban J'orc,try Code RLTi,iom I \ 'olumc \ ' I 2H 
8. John Frewing,January 12,2012 
Amendment Request: The canopy target approach should not be used because the CAC 
was not provided any alternatives. "I urge you to start from the survey finding that not all 
trees should be allowed to be removed, subject to mitigation, and then ask staff to develop 
alternatives, which are in actual practice around the country." 
Staff Response: Alternatives to the proposed code were considered, but the CAC selected 
the canopy target approach as the preferred alternative. 
In working with the CAC, staff developed pre-meeting surveys on each of the code topics to 
differentiate between items where there was general agreement and general disagreement. 
When there was general agreement on an item, staff drafted code language consistent with 
the CAC's consensus. When there was general disagreement on an item, it was pulled for 
further discussion at a CAC meeting. After discussion at a CAC meeting, staff drafted code 
based on the direction of a majority of the CAC members. Staff then returned with draft 
code language for a consensus decision by the CAC as to whether the draft language was 
consistent with a majority of the viewpoints of the CAC members. 
The question of whether to require a base level of tree preservation was asked as part of the 
pre-meeting survey for the November 10, 2010, meeting of the CAC. The responses varied 
from the CAC members, so the question was pulled for further discussion at the CAC 
meeting. 
At their November 10, 2010, meeting, the CAC formed three small groups to discuss the 
issue in more detail. When reporting back on their discussion results, two of the groups 
were opposed to requiring a base level of preservation and one of the groups was in favor. 
Consistent with the direction of the CAC majority, staff drafted code that did not require a 
base level of preservation, but instead gave bonus credits toward meeting canopy targets to 
incentivize preservation. The CAC further discussed and refined the draft code at 
subsequent meetings. At the meeting on April 13, 2011, the CAC voted on the refined draft 
standards, which included tiered canopy targets based on zoning, no base level of 
preservation and bonus credits to incentivize preservation. Of the nine CAC members 
present, eight supported the draft standards and one did not support the draft standards. 
Mr. Frewing was the dissenting vote, citing the lack of a base preservation requirement as 
one of his reasons for dissention. 
Staff believes the CAC had ample opportunity to discuss alternatives to the proposed code 
which could have included a base requirement for preservation. However, the consensus of 
the CAC was to not require a base level of preservation and the proposed code reflects that 
consensus. 
Staff Recommendation: Do not revise proposedc::ode based on this amendment request. 
Amendment: N / A 
City of Tigard Urban Forestry Code Re,·isions I Volume V I 29 
9. John Frewing, January 12, 2012 
Amendment Request: T he draft code ignores smaller sites, which predominate in Tigard . 
Revise so that code applies to infill development and redevelopment. "The City of Portland 
has set a good example, requiring compliance with the new urban forest code when a 
specified major change occurs on an existing site- e.g., a specified change in square foot o f 
the development or a specified monetary addition to a development. Such provisions should 
be included in the Tigard Code." 
Staff Response: T he draft code does no t ignore smaller sites and redevelopment sites in 
Tigard . 
T he draft code standards are applicable to Minor Land Partitions (see Section 18.790.020, 
page 295 of UFCR Volume II) when lo ts are divided to create two or three lots. T hese infill 
sites represent a significant portion o f potential future development and applying the draft 
canopy standards to Minor Land Partitions support Tigard 's long-term urban forestry goals. 
T he draft code standards are also applicable to larger pro jects such as Subdivisions and 
Planned D evelopments, redevelopment pro jects that require Conditional Use Permits, 
D owntown D esign Reviews and Site D evelopment Reviews (see Section 18.790.020, page 
295 of UFCR Volume II). Redevelopment pro jects are triggered by activities that exceed 
specified thresholds and represent significant opportunities to increase canopy by applying 
the draft code standards in commercial, industrial and institutional areas o f Tigard. 
Staff Recommendation: D o not revise proposed code based on this amendment request. 
Amendment: N I A 
CitY of TiganJ L:rban l:orL">lrr C:mk lh ·,·i>iom I \ 'oluml' \ ' 1 10 
lO. John Frewing,January 12,2012 
Amendment Request: The draft code should be revised to allow public input on future 
changes. 
Staff Response: The public would have input opportunities for changes to the code and 
administrative rules in the UFM. 
Changes to the development code (fitle 18) require public notice and opportunity for appeal 
as governed by Section 18.390.060 of the Tigard Development Code. 
Changes to the municipal code (non-Title 18) are required by ordinance, which is noticed 
publicly through the City Council agenda and packet and governed by Chapter VIII of The 
City of Tigard Charter. Council practice is to adopt potentially contentious municipal code 
ordinances (e.g. urban forestry), following a public hearing, to consider any public input 
prior to voting. 
Changes to administrative rules in the UFM require public notice and opportunity for appeal 
as governed by Section 2.04.070 of the Tigard Municipal Code. 
Staff Recommendation: D o not revise proposed code based on this amendment request. 
Amendment: N / A 
City of Tigard Urban Forestry Code RcYisions I Volume\' I 31 
11. John Frewing,January 12,2012 and February 17, 2012; Opposed by Ken Gertz, 
February 17, 2012 
Amendment Request: Frewing: The construction of the draft code results in the canopy 
approach no t being enforceable. Code relies upon submittal requirements, not approval 
criteria. Canopy cover provisions lack certainty as required by Oregon Revised Statutes and 
LUBA opinions. Include more specific approval criteria and move definiti ons from Title 8 
to Title 18. 0 anuary 12) 
" I ask that staff prepare appropriate changes to include approval criteria in the development 
code . . .. [approval criteria] must be clear and obj ective ... bo th the code and UFM include 
standards which are not clear and objective, for example (y ol II): 
p. 301 "applicable approval criteria" 
p. 303 "any conflicting requirements" 
p. 307 "unreasonable risk", "adequate emergency access" 
p. 309 "minimum required to achieve the desired effect", "preference" 
p. 319 "balancing the considerations" 
p. 387 "unless otherwise approved by the city manager or designee" (February 17) 
Gertz: "Be sure the tree plan is a submission requirement and !1Q1 an approval criteria." 
Staff Response: Staff, in conjunction with the City Attorney, has developed code language 
to ensure the tree canopy cover requirements in the draft code are enforceable for applicable 
land use permits. 
Chapter 18.790 of the code, and Section 10 of the UFM, require tree canopy cover 
requirements to be met for certain Type II and III land use permits (CUP, DDR, MLP, PD, 
SLR, SDR, and SUB). This is clearly stated in code Sections 18.790.020 and 18.790.030 (see 
UFCR Volume II, pages 301 and 303 respectively). T he approval criteria in the chapters, for 
each of these land use permits, references compliance with all applicable development 
requirements, which include the tree canopy cover requirements in Chap ter 18.790 and 
Section 10 of the UFM. T his continues current administration o f the code regarding the 
applicability of the requirements in Chapter 18.790. 
However, staff realizes the summary heading in Section 18.790.030 . .A may be confusing 
because it uses the term "submittal requirements." Staff recommends removal o f the word 
"submittal" from the summary heading for clarification purposes. 
Staff Recommendation: Revise proposed code based on this amendment request. 
Amendment: (Section 18. 790.030 . .A) 
"A. Urban Forestry Plan Subntittal Requirements. i\n urban fores try plan shall:" 
City of Ti1'ard Urban l'orc" rr Code RcTisions I \ 'olumc \ ' I ."12 
12. ODFW,January 20, 2012 
Amendment Request: Add intact forest stands along Fanno Creek in the Hall 
Sti Burnhami Hunziker area. Supply ODFW with process for selection of tree groves and 
allow for public review. 
Staff Response: Staff met with the Planning Commission, City Council and Winter brook 
Planning to develop the criteria for initial review and selection of significant tree groves. 
Based on those meetings, which included consideration of available budget, the initial review 
and selection criteria included contiguous groves of native trees over two acres in canopy 
area. Metro tree canopy maps, GIS technology and field visits were used to identify groves 
that fit the criteria (see Tigard Tree Grove Assessment Report, UFCR Volume II, page 113). 
Specific groves that are not included in the inventory likely did not meet the two-acre size 
threshold. 
The ESEE, which was not yet completed at the time the request for comments, was sent to 
affected agencies. As requested, staff has provided ODFW the ESEE. The ESEE is available 
for public review as well in UFCR Volume III, page 17. 
Staff Recommendation: Do not revise proposed code based on this amendment request. 
Amendment: N I A 
13. ODFW, January 20,2012 I 
Amendment Request: Strike that 'existing' trees may be used as replacement trees 
throughout the code and UFM. 
Staff Response: Section 10, Part 3 of the UFM, specifies that the effective tree canopy 
requirements for development can be met through any combination of planting new trees 
(based on their mature canopy sizes) or preserving healthy existing trees over 6-inch D BH 
(which receive double credit for their existing canopy sizes). However, there may be healthy 
existing trees on a development site that are less than 6-inch DBH that could provide viable 
future canopy growth. 
If existing trees less than 6-inch DBH were not eligible for credit based on their mature 
canopy sizes, there could be an incentive to remove them and replant with new trees. 
Usually, existing trees have established root systems and higher chances of survival than 
newly planted trees. 
Staff Recommendation: Do not revise pro__posed code based on this amendment request. 
Amendment: N I A 
- - --- - ------ -- -----
City of Tiganl Urban Forestry Code Rc,·isions I \' olumc V I 33 
14. ODFW,January 20, 2012; and Sue Beilke, February 6, 2012 
Amendment Request: Add language in the code and UFM to support preservation of 
Oregon white oak and appropriate replacement o f oak with oak, if removal is necessary. 
Staff Response: The CAC consensus was for flexible standards and incentives to preserve 
trees rather than requiring preservation (see G uiding Principles, UFCR Volume I, page 16). 
The flexible standards and incentives for preservation include lot size averaging, setback 
adjustments, sidewalk adjustments, parking adjustments and landscaping adjustments (see 
Section 18. 790.050.C). In addition, double credit towards effective tree canopy requirements 
in Section 10, Part 3 of the UFM, is intended to incentivize the preservation of existing trees. 
T he CAC consensus was also to allow a mix of native and non-native trees to meet effective 
tree canopy requirements (see November 10, 2010, pre-meeting survey in the project 
record). This allows applicants to select the most appropriate trees for preservation and 
planting, based on site conditions. The specific requirement of replacing oak with oak was 
not discussed by the CAC. 
Staff Recommendation: D o not revise proposed code based on this amendment request. 
Amendment: N I A 
15. ODFW, January 20,2012 
Amendment Request: "Add language in the UFM and Code to support leaving 5-20 feet 
of the trunk of a hazard tree located in designated sensitive land s, natural areas, or a 
significant tree grove if hazard tree abatement requires much of the tree to be removed." 
Staff Response: T he CAC discussed this concept but the consensus recommendation was 
to allow the removal of wildlife snags through the same process as for hazard trees, trees 
causing damage, etc. (see Ja nuary 8, 2011, meeting minutes in the project record). Their 
reasoning was that people would generally not go out of their way to remove wildlife snags 
from natural areas, unless there is good reason to do so. The existing code actually requires 
the removal of wildlife snags. The proposed code would allow the removal of wildlife snags, 
but not require their removal if they are not hazards to people or property. The CAC felt 
this moves the city in right direction. 
Staff Recommendation: D o not revise proposed code based on this amendment request. 
Amendment: N I A 
City o iTigard Urban l;orc>try Code Rc,·i>iom I \'olumc \ ' I ."\4 
16. ODFW,January 20,2012 and December 2L2010 (resubmitte9_on January 20, 2012) 
Amendment Request: Add language in the code and UFM that requires 50 percent of 
newly planted trees to be native in a development/ landscape plan. Qanuary 20, 2012) 
Consider requiring only native species be planted in developments. Require street trees be 
native species. (December 21, 2010 and resubmitted on January 20, 2012) 
Staff Response: When surveyed on the issue, the CAC consensus supported the city 
allowing the project designer to select a mix of native and non-native trees, depending on 
site conditions (see November 10, 2010, pre-meeting survey in the project record). 
However, in response to public testimony received on the issue, the Planning Commission 
further discussed whether to increase the relative amount of native tree planting at their 
March 5, 2012, meeting. The commission indicated support for providing bonus credits 
towards effective tree canopy cover requirements for the planting of native trees. They did 
not indicate support for requiring planting of a certain percentage of native trees. Bonus 
credits for native tree planting would encourage the planting of natives, while allowing the 
project designer to select the most appropriate trees depending on site conditions. 
Staff Recommendation: Revise proposed UFM based on this amendment request. 
Amendment: (Section 10, Part 3.M.2) 
" 
c. The mature canopy area (in square feet) of all open grown trees in the tree canopy 
site plan, except for those from the native tree list in the I Jrban Forestry Manual, 
to be planted and maintained within the overall development site and each lot or 
tract (or associated right of way, excluding median trees). 
d. 1.25 times the mature canopy area Qn square feet) of all open grown trees from 
the native tree list in the urban forestry manual in the tree canopy site plan to be 
planted and maintained within the overall development site and each lot or tract 
(or associated right of way excluding median trees). 
e. 1.25 times +the mature canopy area (in square feet) of each stand in the tree 
canopy site plan to be planted and maintained within the overall development site 
and each lot or tract (or associated right of way, excluding median trees). The 
eligible mature tree canopy area shall be the portion directly above the overall 
development site and each lot or tract (or associated right of way). 
f. Divide the tree canopy area (calculated per part 3.M.2.a-tl~ above) for the overall 
development site and each lot or tract by the total area of the overall development 
site and each lot or tract respectively to determine the effective tree canopy cover 
for the overall development site and each lot or tract." ... 
(no te: above lettering is revised due to the insertion of item d) 
(no te: for consistency the Example Supplemental Arborist Report Template 
in Ap_p_endix 9 of the UFM is recommended for amendment per the attached) 
City of Tigard Urban Forestry Code ReYisions I Volume V I 35 
17. ODFW, January 20,2012 and D ecember 21,2010 (resubmitted on J anuary 20, 2012) 
Amendment Request: Add language in the code and UFM that requires native trees 
removed to be replaced with native trees. 
Staff Response: T he CAC consensus recommendation was to allow a mix of native and 
non-native trees to meet effective tree canopy cover requirements (see November 10, 2010, 
pre-meeting survey in the project record). A replacement requirement for native trees was 
not discussed by the CAC. However, Clean Water Service has requirements for native tree 
planting and replacement within vegetated corridors, which would not be precluded by the 
proposed code requirements. 
Staff Recommendation: D o not revise proposed code based on this amendment request. 
Amendment: N I A 
18. ODFW,January 20, 2012 and D ecember 21, 2010 (resubmitted on j anuary 20 2012} I 
Amendment Request: Strike criterion B.2 from Section 6, Part 1 o f the UFM, which allows 
the removal of dead trees from sensitive lands. 
Consider implementing a snag removal permitting process, similar to the tree removal 
permitting process, encouraging avoidance first, trimming second and requiring removal 
mitigation third . 
Staff Response: Criterion B.2 in Section 6, Part 1 allows the removal o f dead trees from 
sensitive lands. 
T he CAC recognized the importance of dead trees and wildlife snags but recommended to 
allow their removal through the same process as hazard trees, trees causing damage, etc. (see 
January 8, 2011 , meeting minutes in the project record). T heir reasoning was that people 
would generally not go out of their way to remove wildlife snags from natural areas unless 
there is a good reason to do so. The existing code actually requires the removal of wildlife 
snags. The draft code would allow the removal of wildlife snags, but not require their 
removal if they are not hazards to people or property. The CAC felt this moves the city in 
right direction. 
Staff Recommendation: D o not revise proposed code based on this amendment request. 
Amendment: N I A 
Cit' of Tigard Urban l'o rcstry Code Rc,·isions I \'olumc \ ' I :16 
19. ODFW, January 20, 2012 
Amendment Request: Strike "In addition to newly planted trees, existing trees less than 6" 
DBH can be used as replacement trees .... " in the UFM Section 6. 
Staff Response: Chapter 8.12 of the proposed code requires tree removal permits for native 
trees in sensitive lands that are 6-inch DBH or greater. Permit approval would be contingent 
on replacement with native trees on a 1:1 basis by Section 6 of the UFM. If existing trees less 
than 6-inch DBH were not eligible for credit, there could be an incentive to remove them 
and replant with new trees. Usually, existing trees have established root systems and a higher 
chance of survival than newly planted trees. 
Staff Recommendation: Do not revise proposed code based on this amendment request. 
Amendment: N I A 
-- --------------
20. ODFW, January 20, 2012; and Sue Beilke, February 6, 2012 
Amendment Request: Provide language in the UFM specifically for Oregon white oaks 
impacted in Sensitive Lands. 
Staff Response: The consensus recommendation of the CAC was to develop consistent 
standards for tree removal permits outside the development process, without regulating 
additional tree situations (see Guiding Principles, UFCR Volume I, page 18). Native trees 6-
inch DBH or greater in sensitive lands would be permitted for removal administratively by 
Section 6 of the UFM, if they are hazardous, dead, in advanced decline, causing property 
damage, approved for removal with development, a fire hazard or thinned for forest health 
under arborist or forester supervision. Replacement with native trees would be required on a 
1:1 basis by Section 6 of the UFM. Otherwise, following a public review process and 
approval through a discretionary process by a city board or committee, removal may be 
permitted (see Section 8.12.040.B, UFCR Volume II, page 91). The board or commission 
could use their discretion in conditioning replacement. Elevated preservation and 
replacement requirements for Oregon white oak trees were not specifically discussed by the 
CAC. 
Staff Recommendation: D o not revise proposed code based on this amendment request. 
Amendment: N I A 
------ --
21. ODFW,January 20, 2012; and Sue Beilke, February 6, 2012 I 
Amendment Request: Include code specifically supporting Oregon white oak conservation 
within the city. Enroll all Oregon white oaks 80 years or older on city property as Heritage 
Trees, to raise oak conservation awareness. Identify mature oaks on private land throughout 
the city, and notify landowners of the resource they have on their property and the support 
services offered from the city if enrolled as a Heritage Tree. 
Staff Response: The CAC consensus recommendation was for voluntary Heritage and 
Significant Tree programs, rather than enrolling trees in these programs without landowner 
consent (see Chapter 8.18, UFCR Volume II, page 101). 
Staff Recommendation: Do not revise proposed code based on this amendment request. 
Amendment: N I A 
------ - - --- -- --
City of Tigard Urban Forestry Code RcYisions I Volume V I 37 
22. ODFW, January 20, 2012 
Amendment Request: Require a rninimum o f 1 replacement tree if a Heritage tree is 
removed in Section 9 o f the UFM. 
Staff Response: Section 9 of the UFM does no t require replacements because H eritage 
trees are uniquely designated and highly protected due to their age, size, species, horticultural 
quali ty or historic importance. Replacement trees would not necessarily replace the unique 
values for which the original Heritage trees were designated. T herefore, recognizing and 
pro tecting replacement trees as if they were H eritage trees would not be appropriate. 
Staff Recommendation: D o not revise proposed code based on this amendment request. 
Amendment: N I A 
23. ODFW, January 20, 2012 
Amendment Request: Section 18.790.050.D references Section 10, Part 5, o f the UFM, 
Significant Tree G rove Preservation Considerations o ften. Part 5 should be modified so that 
dead or dying trees that provide wildlife value, and that do not pose a threat to humans or 
structures, do not indirectly affect the rating of the Significant Tree Grove by the arborist. 
Staff Response: T he CAC consensus was for the list o f considerations to act as general 
guide for preserving viable tree groves. Their preference was for flexibility in the 
considerations to allow preservation decisions to be made on a case-by-case basis (see 
J anuary 8, 2011, meeting minutes in the project record). T he considerations do no t preclude 
dead or dying trees that provide wildlife value, as long as they are not hazards to people or 
pro_pe r!J1. 
Staff Recommendation: D o not revise proposed code based on this amendment request. 
Amendment: N / A 
24. ODFW, January 20, 2012 
Amendment Request: Include number of dead/ dying trees in tree preservation and 
removal site plan in Section 10, Part 1 or Part 3, o f the UFM. 
Staff Response: Section 10 of the UFM would require all trees within or near the 
development impact area to be inventoried and numbered on the tree preservation and 
removal site plan. This includes dead and dying trees. 
Staff Recommendation: D o not revise proposed code based on this amendment request. 
Amendment: N I A 
Ciry of Tigard Urban J.'ornary Code lh :,·isions I \ 'olutnc \' I .)X 
25. ODFW,January 20,2012 
Amendment Request: Strike the base requirement for 10,000 square feet of significant tree 
grove canopy not already protected by floodplain, stream corridor and/ or wetland 
regulations, to qualify for significant tree grove preservation incentives and replace with 
more appropriate language or leave out. 
Staff Response: The CAC consensus recommendation was to require a base preservation 
requirement to utilize the tree grove preservation incentives (see Guiding Principles, UFCR 
Volume I, page 17) . Their reasoning was, for applicants to benefit from the tree grove 
preservation incentives in Section 18. 790.050.D (minimum density reduction, density 
transfer, additional building height, etc.), there should be corresponding community benefit. 
For example, 20 feet additional building height should not be allowed for preserving one tree 
that happened to be part of a significant tree grove. The proposed base preservation 
requirement is 10,000 square feet, or roughly 1/ 4 acre of tree grove canopy, to be eligible for 
the tree grove preservation incentives. 
In many cases, development is already limited or prohibited in floodplains, stream corridors 
and wetlands by other regulations. Therefore, the proposal is not to provide incentives for 
preserving tree groves in areas already protected by other regulations. Instead, the proposal 
is to provide incentives for preserving at least 10,000 square feet of at-risk tree groves, not 
already protected by other regulations. 
Staff Recommendation: Do not revise proposed code based on this amendment request. 
Amendment: N /A 
26. ODFW, D ecember 12, 2010 and resubmitted onJanuary 20, 2012 
Amendment Request: Require planting plans from developers that consider spatial 
arrangement and vertical structure, as well as species and quantity of trees. 
Staff Response: The Urban Forestry Plan requirements in Section 10 of the UFM address 
tree planting and preservation requirements. There are standards for spatial arrangement, 
species, and quantity of trees based on tree care industry standards. Vertical structure 
standards such as requiring shrubs, herbs, and other understory plants are out of scope for 
the UFCR. It is important to note that other standards such as landscaping and screening 
requirements in Chapter 18.745 and native planting required by Clean Water Services' 
Design and Construction Standards would continue to apply and result in vertical structure. 
Staff Recommendation: Do not revise proposed code based on this amendment request. 
Amendment: N /A 
City of Tigard Urban I 'orcs try Code Rc,·isions I Volume V I 39 
27. ODFW, December 12, 2010 and resubmitted onJanuary 20, 2012 
Amendment Request: Implement a tree removal season: September 1 >r to February 1 >r, 
with special consideration given to the months o f August and March. T his is for purpose of 
pro tecting nesting birds Qrotected by the Migratory Bird Treaty Act. 
Staff Response: T he Migratory Bird Treaty Act is a federal law, administered by the US 
Fish and Wildlife Service, that protects specifically listed species of birds. T he UFCR 
addresses the preservation, planting and maintenance o f trees. It would be out of scope o f 
the UFCR to implement these federal regulations, through such restrictions as a tree removal 
season, aimed at protecting listed species o f birds. 
When removing trees, it is the sole responsibility o f applicants to comply with all applicable 
state and federal regulations, such as the Migratory Bird Treaty Act. It is the city's practice 
however to highlight the applicants' responsibilities to comply with applicable regulations 
when issuing tree removal permits. 
Staff Recommendation: D o not revise proposed code based on this amendment request. 
Amendment: N I J\ 
28. ODFW, December 12,2010 and resubmitted on January 20,2012 
Amendment Request: Require that tree habitat potential be included in tree inventories. 
Staff Response: As further explained in the Tree Grove E SEE Analysis beginning on 
UFCR Volume III, page 27, wildlife habitat value and connectivity were key evaluation 
criteria in the inventory and selection o f significant tree groves. T he proposed 
Comprehensive Plan Amendment would es tablish an overlay district for significant tree 
groves, making them eligible for regulatory incentives and flexible standards for preservation 
in Section 18.790.050.D . 
T he Statewide Goal 5 rule requirements require adoption of the inventory and protection 
program prior to implementing regulations that pro tect wildlife habitat during the 
development process. T he city canno t require additional discovery and protection o f wildlife 
habitat during the development process without adhering to G oal 5 rule requirements. 
Staff Recommendation: D o no t revise proposed code based on this amendment request. 
Amendment: N I A 
Cin· of Tigard L'rban l'orc>try Code Rc,·i>iom I \ 'olumc \ ' I -l() 
Amendment Request: Concerned about the methodology used to estimate potential tree 
canopy cover and implications for the draft code, as "the [November 7, 2011] memo is not 
understandable to me or the general public ... could you have the consultant try again (maybe 
with graphics) how they came up with the ultimate potential for canopy cover in Tigard (i.e. 
the 100% of cano covera e which is the start for the UFP oal of 40% cano co vera e)?" 
Staff Response: The canopy standards memo in the UFCR ry ol. III, page 7), demonstrates 
why staff believes the effective tree canopy standards in the draft code are achievable. The 
approach and results for estimating possible tree canopy are attached to the canopy 
standards memo. 
To simplify, the assumptions are that tree canopy is possible on typical lots, except within 
building footprints and 50% of lot area not already occupied by tree canopy (to account for 
open space preference and poor growing conditions). 
Based on these assumptions, tree canopy for each zoning district exceed the minimum that is 
required in the draft code. More importantly, the requirements in the draft code have been 
tested through the peer review phase, and are shown to be achievable on a range of actual 
develo ment ro·ects see Peer Review, UFCR, Vol. II, . 463 . 
Staff Recommendation: Do not revise osed code based on this amendment re uest. 
Amendment: N I A 
------ --- - -- ----------
30.John Frewing,January 23,2012 
Amendment Request: Include a provision to the effect that the same root volume should 
not be counted for more than one tree. 
Staff Response: The Soil Volume Memo (UFCR, Vol. III, p. 13) explains that the soil 
volumes standards in the draft code are based on current tree care industry research. In 
reviewing this research, staff could not find any provisions for discounting soil volume to 
account for situations when multiple trees share rooting space. In the proposed code, the 
soil volume standards are for street and parking lot trees. These tree types are required to be 
spaced at distances to minimize canopy and root competition. Therefore, staff does not 
believe shared soil volumes calculations should be discounted. 
Staff Recommendation: Do not revise proposed code based on this amendment request. 
Amendment: N I A 
- ---- ------- -- ---
City of Tigard Urban Forestry Code Rc,·isions I Volume V I 41 
31.j()hn Frewing,January 23, 2012 
Amendment Request: The Goal 5 rule requirements should apply to tree canopy cover 
regulations, soil volume regulations, etc. , in addition to the tree grove preservation 
incentives. 
Staff Response: T he Goal 5 rule requirements are no t applicable to canopy cover 
regulations, soil volume regulations or o ther development code regulations o ther than the 
tree grove preservation incentives in Section 18. 790.050.D. T he D epartment of Land 
Conservation and D evelopment (DLCD) staff addressed this question directly, in response 
to the city's request for clarification on thi s issue, during the Comprehensive Plan 
Amendments incorpora ting urban fores try goals and policies (see D LCD correspondence in 
the project record). DLCD explained that: 
"With regard to establishing policies to protect and encourage the growth of trees within the 
city, although there may be some shared objectives, there is not necessarily a direct link 
between such a policy and Goal 5 . .. the applicability requirement for O AR 660-023-0250 is 
very specific ... [in relevant part, to actions] that create or amend a resource list or a portion o f 
an acknowledged plan or land use regulation adopted in order to pro tect a significant Goal 5 
resource." 
T he proposed tree canopy cover and soil volume requirements do not create or amend a 
resource list or land use regulation adopted in order to protect a Goal 5 resource (see 
summary of the city's Goal 5 program in the pro ject record). 
Staff Recommendation: D o not revise the proposed code or E SEE analysis based on this 
amendment request. 
Amendment: N I A 
32. Cleon Cox, February 6, 2012 
Amendment Request: Fees and taxes associated with these code amendments should not 
negatively impact property owners. 
Staff Response: T he proposed code has been designed so it is achievable on the typical 
range of development scenarios in Tigard (see Peer Review, UFCR, Vol. II, p. 463). The 
proposed tree canopy fee is an option for not providing trees and is a conservative estimate 
for the value o f tree canopy (UFCR, Vol. III, p. 15). 
Specific permit costs are established by the City Council through the Master Fees and 
Charges Schedule and allow for partial or full administrative cost recovery. However, one o f 
the CAC's G uiding Principles is to provide a low- or no-fee administrative review process 
for the most common tree permits (UFCR, Vol. I, p. 19). 
Staff Recommendation: D o not revise proposed code based on this amendment request. 
Amendment: N I 1\ 
City o f Tigard L1rban h>rcs lry Colle RcYisions I \'olUinc \ ' I 42 
33. Brian Lewis, February 6, 2012 
Amendment Request: Agrees with Mr. Frewing that tree count is better than tree canopy 
reg_uirements. There should be a minimum tree count. 
Staff Response: When drafting the Development Code revisions, staff studied a tree density 
requirements (requiring X number of trees per square feet of development area, sometimes 
referred to as "tree count") and compared it with a tree canopy requirements (requiring X 
square feet of canopy per square feet of development area). The tree canopy requirements 
was selected as the preferred alternative for the following reasons: 
• The tree canopy requirement allows more flexibility for the project designer to meet code 
requirements due to the wide variation of canopy shapes by species. A tree density 
requirement presents the project designer with more limited options to meet numerical 
tree planting requirements. 
• The tree canopy requirement is more consistent with urban forest science and the city's 
long-term urban forestry goals. The benefits of trees (economic, environmental and 
social) are derived primarily from their canopies, rather than number of trees. The tree 
canopy requirement encourages large stature, appropriately spaced trees, which have the 
highest benefit/ cost ratios. A tree density requirement allows small stature, closely 
spaced trees to meet numerical requirements. 
• The tree canopy requirements requires the project designer to consider future canopy 
growth, which helps ensure that trees are properly placed within a site to become long-
term amenities. The tree canopy requirement encourages appropriate tree spacing and 
setbacks from buildings by highlighting mature canopy growth, whereas a tree density 
requirement focuses on planting a certain number of trees and does not take mature 
growth into account. 
• The tree canopy requirement provides more consistency in development outcomes. For 
example, a parking lot planted to meet a numerical tree density requirement can look very 
different after future growth, depending on whether small ornamental trees or large 
shade trees are selected. The tree canopy requirement helps normalize outcomes. 
• Planting trees to meet either a tree canopy requirement or a tree density requirement 
both rely upon successful establishment and long-term maintenance by property owners. 
However, the tree canopy requirement focuses more on long-term growth during the 
initial design phase, so that trees are more likely to become long-term site amenities. 
In response to public testimony received on the issue, the Planning Commission further 
discussed their preference for a tree density versus a tree canopy requirement at their March 
5, 2012, meeting. The commission indicated support for continuing with a tree canopy 
requirement. 
Staff Recommendation: Do not revise proposed code based on this amendment request. 
Amendment: N I A 
City o f Tigard Urban Forestry Code ReYisions I Volume V I 43 
34. Ken Gertz, February 6, 2012 
Amendment Request: 18.360.090 - The wording "where possible" is vague and opens the 
tree plan to appeal. Change to a clear and objective requirement and word to allow 
development to maximum allowed. 
Staff Response: This phrase "where possible" in Section 18.360.090 is existing language 
addressing the relationship of buildings to the natural and physical environment. Because of 
its broad application, revising this phrase is out of scope for the UFCR. 
Staff Recommendation: D o not revise proposed code based on this amendment request. 
Amendment: N I A 
35. Ken Gertz, February 6, 2012; Stonebridge Homes, February 14, 2012; and JT Smith 
Companies, February 15, 2012 
Amendment Request: 18.530.050.B - Change requirement for stree t trees from 3" 
minimum caliper to 2" minimum caliper. 
Staff Response: T he requirement for three-inch caliper trees in Section 18.530.050.B is an 
existing code provision when increasing lot coverage from 7 5% to 80% in Industrial Zoning 
Districts. Because this existing provision was likely a compromise as part of a past code 
revision project, staff recommends retaining the _provision. 
Staff Recommendation: D o not revise proposed code based on this amendment request. 
Amendment: N I A 
Ciry ofTiganl Urban l'orc,tn· Code· Rc,·i,ion' I \ 'olumc \ ' I +l 
36. Ken Gertz, February 6, 2012; Opposed by John Frewing, February 17, 2012 
Amendment Request: Gertz: 18.790.030.B- Remove 20% minimum canopy requirement, 
canopy coverage should be averaged out across the site. 
Frewing: "I support this idea, with the provision that if a lot has even a single tree > 6 inches 
in diameter dbh, one such tree must be saved on each lot." 
Staff Response: Early in the process, staff initially proposed the tiered tree canopy 
requirements to be met on a lot-by-lot basis, in addition to the overall development. The 
CAC recommended allowing averaging of canopy across the overall development site, while 
setting a minimwn per lot tree canopy requirement. Staff proposed a 20% per lot minimum 
requirement at the April13, 2011, meeting and the committee approved the proposal by 
consensus (see minutes in the project record). The rationale for having a minimum per lot 
tree canopy requirement is to spread the distribution of trees, and therefore tree benefits and 
maintenance responsibilities, more evenly across a development site. 
In response to public testimony received, the Planning Commission expressed interested at 
their March 5, 2012, meeting regarding potentially providing more flexibility on this issue. 
The Planning Commission considered that reducing the per lot tree canopy requirement 
would likely not raise major issues since it was not a major part of the deliberations when 
developing the proposal (see summary of community ideas and concerns, UFCR Volwne I, 
page 36). Also, street tree requirements in Section 18.745.040 would still apply and support 
an evening of the distribution of trees across the development site. Finally, if the per lot tree 
canopy requirement were reduced, the effective tree canopy requirement for the overall 
development site would be reduced, which may be a desired side effect for the commission. 
In reviewing past development projects that were peer reviewed by AKS Engineering and 
Forestry, staff found only four residential lots that had to plant additional trees in backyards 
to meet the 20% per lot minimum requirement (UFCR, Volume II, p. 463 and the additional 
peer review provided in the March 5, 2012, Planning Commission meeting packet). While 
the sample size is small, staff found that if the per lot minimum were reduced to 15% it 
could be met by planting one medium stature street tree in two of the lots, thus eliminating 
trees in the backyards. The unique configurations of the other two lots require one backyard 
tree to meet the 15% per lot minimum requirement. Therefore, staff recommends the 
commission consider reducing the per lot minimwn to 15%. 
Staff Recommendation: Revise proposed code and UFM based on this amendment 
request. 
Amendment: (Section 18. 790.030.B) 
"B. Tree Canopy Fee. If the supplemental arborist report demonstrates that the 
applicable standard percent effective tree canopy cover in Section 10, part 3, item N. will not 
be provided through any combination of tree planting or preservation for the overall 
development site (excluding streets), or that the ~ 1.5 percent effective tree canopy cover 
will not be provided through any combination of tree planting or preservation for any 
individual lot or tract (when the overall development site meets or exceeds the standard 
percent effective tree canopy cover), then the applicant shall provide the city a tree canopy 
City of 'l'it,>ard Urban Forestry Code Revisions I Volume V I 45 
fee according to the methodology outlined in Section 10, part 4 o f the UFM. 
(Section 18.790.050.D.5) 
1. Adjustment to Minimum E ffective Canopy Requirement. T he 
requirement for~ 1.5 percent effective tree canopy cover per lo t is not required 
when: 
(Section 18.790.050.D.5, Commentary) 
T he fifth flexible and incentive based standard is an adjustment to the minimum effective 
canopy requirement. A standard Urban Forestry Plan requires ~ 15_ percent effective tree 
canopy per lot in addition to the overall development site effective canopy requirement 
which is based on zoning (25, 33 or 40 percent). 
(UFM Section 10, Part 3.0 ) 
0 . If the percent of effective tree canopy cover is less than the applicable standard 
percent in item n above for the overall development or less than~ 15_ percent for any lot or 
tract (when the overall development site meets or exceeds the standard percent effective tree 
canopy cover in item n), calculate the tree canopy fee required to meet the applicable 
standard percent effective tree canopy cover in item n above for the overall development site 
or~ 15_ percent effective tree canopy cover for each lot or tract (only if the overall 
development site meets or exceeds the standard percent effective tree canopy cover in item n 
but individual lots or tracts do provide ~ 15_ percent effective tree canopy cover) according 
to the methodology in Section 10, part 4 o f the Urban Forestry Manual. 
(UFM Section 10, Part 4.A.2) 
2. In cases where the overall development site meets the standard percentage in 
part 3.N above yet the percentage o f effective tree canopy cover is less than~ 
15_ percent for any individual lot or tract, find the difference (in square feet) 
between the proposed effective tree canopy cover and~ 15_ percent effective 
tree canopy cover for each deficient lo t or tract and multiply the difference (in 
square fee t) by:" . .. 
37. Ken Gertz, February 6, 2012 
Amendment Request: 18. 790.030.C - "you skipped C and went directly to D" 
Staff Response: This scrivener's error should be corrected. It is important to no te the city 
recorder is authorized to correct such errors by Section 1.01.080 o f the Tigard Municipal 
Code. 
Staff Recommendation: Revise proposed code based on this amendment request. 
Amendment: (18.790.030.C) 
~.c_ Tree Canopy Fee Use. Tree canopy fees provided to the city shall ... " 
City of TigarJ Llrban l;orL·stry CoJc Rc,·isions I \ 'olumc \ ' I -l(> 
38. Ken Gertz, February 6, 2012 and February 17, 2012; O pposed by John Frewing, 
February 17, 2012 
Amendment Request: Gertz: 18.790.050.C.3- Add language allowing sidewalks in 
easements with reduced setbacks for preservation and planting. 
Frewing: "I oppose such a change. Such a change is simply a ruse to increase density by 
about 10 percent on a given project, allowing 11 lots on a typical site rather than 10 lots. 
This translates to about a 10 percent increase in profit for the land developer without any 
corresponding public benefits, since the already required planter strip will contain trees." 
Staff Response: The city's development engineer is already authorized to approve sidewalks 
in easements. It is not necessary to restate the requirement in Section 18.790.050.C.3. 
Staff Recommendation: Do not revise proposed code based on this amendment request. 
Amendment: N I A 
---- --- - -- -
39. Ken Gertz, February 6, 2012 
Amendment Request: 18. 790.070.A&B is confusing and ambiguous. Change language to 
add more clarity. 
Staff Response: The proposed language in Section 18.790.070 is clear. Modifications to the 
Urban Forestry Plan component of an approved land use permit are allowed through a Type 
I process. This is documented in the guiding principles for the urban forestry standards for 
development (see UFCR Volume I, page 16) and in the commentary for the proposed code 
amendments (see UFCR Volume II, page 332). Certain minor modification such as 
removing hazard trees, changing tree planting plans, and modifying tree protection fencing, 
when approved by the project arborist, would be allowed outright without a permit by 
Section 18. 790.070.B. 
Staff Recommendation: Do not revise proposed code based on this amendment request. 
Amendment: N I A 
--- -----
40. Ken Gertz, February 6, 2012 and February 17, 2012 
Amendment Request: 18.790.070.b- Modification process should allow payment of fee in 
lieu as an allowed change to an approved canopy plan. 
Staff Response: The proposed modification process in Section 18.790.070 provides 
significant flexibility for applicants to modify their approved urban forestry plans after land 
use approval. While the modification process is intended to allow applicants to adapt their 
plans in response to unforeseen circumstances during the course of development, staff 
believes this should be balanced with community expectation of a certain amount of trees 
post development. For example, if an applicant's approved plans are to plant 25% effective 
tree canopy cover for a development, and they then modify those plans by paying a fee in 
lieu o f providing any tree canopy, community expectations may not be met. 
Staff Recommendation: Do not revise proposed code based on this amendment request. 
Amendment: N I A 
Ci ty of Tigard Urban Forestry Code Rc,·isions I \' olumc V I 47 
41. Ken Gertz, February 6, 2012 and February 17, 2012 
Amendment Request: 6-1 .A.6 [section not found, possibly referencing B.6) - Change 
approval criterion to trees not listed in the native tree list for clarity. 
"Section 6 part 1 C" Don't include weed trees for replacement/ permits 
Staff Response: Chapter 8.12 of the proposed code requires permits for the removal of 
native trees over 6 -inch trunk diameter in sensitive lands. This would be a revision from 
current existing code that requires permits for the removal for all trees over 6-inch trunk 
diameter in sensitive lands. 
The approval criteria for removal are listed in Section 6, Part 1 of the UFM. Criterion B.6, in 
Section 6, Part 1, says "the tree is listed on the nuisance tree list." This criterion is 
unnecessary because trees on the nuisance tree list are not native, and therefore not subject 
to permit requirements by Chapter 8.12. This criterion could be struck. 
The replacement criteria in Section 6, Part 2 of the UFM specify that "replacement trees 
shall be selected from the native tree list in the UFM." Therefore, nuisance (weed) trees 
would not be allowed as replacements. 
Staff Recommendation: Revise proposed UFM based on part one of this amendment 
request. 
Amendment: (Section 6, Part 1.B.6) 
6:- "The tree is listed on the nuisance tree list. 
(note: numbering of the section is revised and cross reference to the 
Nuisance Tree List in the sidebar is struck due to the deletion of item 6) 
(Section 6, Part 1.C) 
C. Unless removed for thinning purposes (part 1.B.++ 1Q above) the city manager or 
designee shall condition the removal of each tree in sensitive lands upon the 
planting of a replacement tree in accordance with the Sensitive Lands Tree 
Replacement Standards in Section 6, part 2 of the UFM." 
City of TiganJ Urban l;orcstn· CoJc Rc,·isions I \ 'olumc \ ' I 4X 
42. Ken Gertz, February 6, 2012 
Amendment Request: Section 10, Part 2 of the UFM - Requests Tree Canopy Site Plan 
requirements be amended to allow a more general delineation of trees to be planted to allow 
an applicant to not locate every tree on the tree plan, and allow movement of trees during 
building permit review. 
Staff Response: Section 18. 790.070.B.2 allows modification of the quantity, location, or 
species of trees to be planted in the tree canopy site plan after land use approval 
administratively without an additional permit. This provides flexibility for necessary changes 
during the building permit approval process. 
Staff Recommendation: Do not revise proposed code based on this amendment request. 
Amendment: N I A 
43. Ken Gertz, February 6, 2012 and February 17, 2012 
Amendment Request: Section 10, Part 2 - Medium size street trees should be allowed in a 
standardplanter strip to allow more canopy over streets. 
Staff Response: Table 18.810.1 in the Tigard Development Code lists the minimum 
landscape width for standard street cross sections as five feet (excluding curbs). Section 10, 
Part 2.L.6, of the UFM specifies that medium stature street trees shall not be planted with 
the center of their trunks closer than 21/z feet from any hard surface paving. The 
specifications in the UFM were designed to allow medium stature street trees to be planted 
in standard landscape strips. 
Staff Recommendation: Do not revise proposed UFM based on this amendment request. 
Amendment: N IA 
44. Ken Gertz, February 6, 2012 
Amendment Request: Page 393, ].6, - Correct typo " ; and" at the end of the sentence. 
Staff Response: Scrivener's errors should be corrected. The proposed code and UFM will 
be further reviewed to ensure the format of lists conform to AP standards. It is important to 
note the city recorder is authorized to correct such errors by Section 1.01.080 of the Tigard 
Municipal Code. 
Staff Recommendation: Do not revise proposed UFM at this time based on this 
amendment request. Consult AP standards to ensure standardized format for lists. 
Amendment: N I A 
- ·--· - --
City o f Tigard Urban Forestry Code Rc,·isions I Volume \' I 49 
45. Ken Gertz, February 6, 2012 and February 17, 2012 
Amendment Request: Section 10, Part 3.M. 1 - Subtract "problematic terrain" from area 
calculations from each lo t and tract, including: wetlands, water quality areas, rock outcrop 
areas, steep slopes, walkways, private drives, flags o f flag lo ts, soil conditions and other 
situations where the planting of trees would no t be viable as represented by the project 
arborist. 
Staff Response: The UFCR CAC reached consensus to draft achievable effective canopy 
standards for development that are tiered based on zoning district (see G uiding Principles, 
UFCR Volume I, page 15). 
Staff and outside consultants tested the tiered standards on a wide range of development 
projects to ensure the draft effective canopy standards are achievable, result in a reasonable 
balance between trees and development and do no t force payment of fees in lieu or 
discretionary review for typical projects . T he test projects included "problematic terrain" 
such as wetlands, water quality areas, steep slopes, walk·ways, priva te drives, flags of flag lo ts, 
poor soil conditions and o ther challenges. T he peer review results demonstrate that the 
standards are achievable without payment o f fees in lieu or discretionary reviews even with 
these challenges (see UFCR Volume II, page 463). 
Staff Recommendation: D o not revise proposed code based on this amendment request. 
Amendment: N I J\ 
------- --
46. Ken Gertz, February 6, 2012; Stone Bridge Homes NW, February 14, 2012; JT Smith 
Companies, February 15, 2012 
Amendment Request: Reduce minimum canopy cover standards for residential pro jects. 
Gertz [verbal comments o f February 6]: T he canopy requirements are too high for an urban 
area and should be reduced to: 
No minimum requirement < 5,000 square feet Oot size) 
20% requirement= 5,000 square feet 
25% requirement > 5,000 square feet 
Special category: single story residence 
Gertz [written comments o f February 6]: Section 10, Part 3 N.- HBA believes that 40% is 
too high, the majority o f developable land has no trees, and find 40% unachievable without 
mitiga tion. "We find a more reasonable number would be 25-30% for R4.5 and above and 
20% on R-7 and No requirement o ther than street trees for smaller than R 7 lots, because the 
street trees are the only option." 
Stone Bridge H omes N \'\1 & JT Smith Companies: Reduce minimum canopy requirements 
for low and medium density residential projects down to 25% coverage, and medium-high 
and high density residential projects down to 20% coverage. 
Cit::r of TigarJ Urban l 'or~'try CoJ~ R ~,· isions I \ 'olumc \ ' I 511 
I 
Staff Response: While staff does not recommend revising the proposing code per this 
amendment request, other recommended revisions would have the effect of reducing the 
effective tree canopy requirements towards the requested amounts. 
The UFCR CAC reached consensus to draft achievable and balanced canopy requirements 
for development that are tiered based on zoning district. For example, the requirements 
require development in low density residential areas to have more trees than are required in 
areas of dense zoning, such as Downtown Tigard (see Guiding Principles, UFCR Volume I, 
page 15). 
To implement the consensus of the CAC, staff analyzed possible percent canopy for each 
zoning district using the same methodology developed to set canopy goals for the Urban 
Forestry Master Plan and also in an updated methodology using Light Detection and 
Ranging (LiDAR) technology (see UFCR Volume III, page 9). 
The results of the analyses were then used in conjunction with the minimum percent 
landscaping requirements in the Tigard Development Code to place the various zoning 
districts within one of three tiers. The exception is school sites, which were placed in the 
"dense zoning" tier 3 to ensure sufficient room for sports fields (see UFCR Volume III, 
page 11): 
Tier 1: 40% effective canopy 2 
Tier 2: 33% effective canopy3 
Tier 3: 25% effective canopy4 
It is important to note that effective canopy is very different from actual canopy within the 
lot lines of a particular development. To meet draft effective canopy requirements, the 
preservation of existing trees is granted double canopy credit, and planting of street trees is 
granted full canopy credit, even though half of their canopies overhang streets, which are not 
part of the calculations. 
When considering these factors, the actual canopy required for a particular development 
would fall into the following ranges: 
Tier 1: 16-40% actual canopy 
Tier 2: 13-33% actual canopy 
Tier 3: 10-25% actual canopy 
The low end of each range represents sites with many existing trees that are preserved and 
maximization of street tree canopy. The high end of each range represents sites with no 
2 R-1, R-2, R-3 .5, R-4.5, R-7, and R-12 
3 R-25, R-40, C-N, C-C, C-G, C-P, MUE, J\fUE-1, J\fUE-2, 1\IUC, 1\fUR, and I-P 
4 1\fU-CBD, J\fUC-1, I-L, I-H, and schools (18.130.0500)) 
City of Tigard Urban Forestry Code Rn isions I Volume V I 51 
existing trees and no street tree canopy (all trees planted so the mature canopy stays within 
the lo t lines). T he staff analysis found that the possible percent canopy for each zoning 
district falls within the actual canopy range for their corresponding tiers above (see UFCR 
Volume III, page 11 ). 
T he double canopy credit for preserva tion provides a viable option for meeting canopy 
requirements in the draft code, while incentivizing preservation. T his is because buildable 
lands have significant existing tree resources from which to draw. Staff performed a G IS 
analysis of the city 's buildable lands inventory and determined that buildable lands have an 
average of 41 % existing canopy cover (see April1 3, 2011 CAC meeting packet, pages 45 to 
46 in the project record). 
In many cases, development (and tree removal) is restricted on a portion o f a development 
site due to existing sensitive lands pro tections (for wetlands, streams, floodplains, etc.). Staff 
performed a G IS analysis of existing canopy that is pro tected on buildable lands due to its 
location in protected sensitive lands. The analysis demonstrated that an average o f 12.29% of 
canopy on buildable lands would be preserved due to its location in sensitive lands. 
T herefore, because of double credit for preservation, development on buildable lands would 
achieve an average of 24.58% effective canopy through the preservation o f trees that are 
already required to be preserved (see April 13, 2011 CAC meeting packet, pages 45 to 46 in 
the project record). 
Staff and outside consultants tested the tiered requirements on a wide range of development 
pro jects to ensure the dra ft effective canopy requirements are achievable, result in a 
reasonable balance between trees and development, and do not force payment o f fees in lieu 
or discretionary review for typical projects. 
T he peer review demonstrates that the requirements are achievable without payment of fees 
in lieu or discretionary reviews (see UFCR Volume II, page 463). 
Based on these analyses, staff is confident that the draft effective tree canopy requirements 
would result in a reasonable balance between trees, development and open space. 
In response to public testimony received on the issue, the Planning Commission further 
discussed whether to modify the draft effective canopy requirements at their March 5, 2012, 
meeting. While the commission indicated their support for retaining the draft requirements, 
they also indicated support for granting bonus credits for planting native trees. If the staff 
recommendation of 1.25x credit for plan ting natives is approved the canopy ranges would be 
reduced to the following amounts for projects that rely on native trees to meet the 
reqwrements: 
Tier 1: 16-32% actual canopy 
Tier 2: 13-26% actual canopy 
Tier 3: 10-20% actual canopy 
CitY o f Tigard Urban l'or~> trr Code Rc,-isions I \ 'olumc \ ' I 52 
In addition, if the staff recommendation of reducing the per lot effective canopy 
requirement from 20 percent down to 15 percent is approved, that would further reduce the 
amount of trees as explained in the staff response to amendment reguest 36 above. 
Staff Recommendation: Do not revise proposed code based on this amendment request. 
Amendment: N / A 
City of Tigard Urban Forc~tr)' Code Rc1·isions I Volume \ ' I 53 
47. Ken Gertz, February 6, 2012 
Amendment Request: Section 10, Part 4A.1 & 2 - Fee in lieu for no t meeting minimum 
requirements is too high. It should be based upon actual cost to plant those trees right now, 
rather than on the future canopy of the tree. Viewed as a "back door way to legally replace 
the current tree fund with what we feel is an SD C." 
Staff Response: (much o f this staff response is from the Tree Canopy Fee memo, UFCR 
Volume III, page 15) T he draft code includes canopy standards for development based on 
zoning. For example, development in low density residential areas will be required to have 
more trees than in areas of dense zoning, such as D owntown Tigard. 
The draft canopy standards have been carefully crafted and have undergone a peer review to 
ensure that they are achievable on the typical range of development scenarios in Tigard. For 
added flexibility, a discretionary review option is proposed to allow other green building or 
development methods (e.g. solar panels, green roofs, rain gardens, etc.) in place of planting 
or preserving the required amount o f trees. Finally, a fee-in-lieu option is proposed to allow 
applicants to pay a " tree canopy fee" to replace the value of canopy not provided through 
tree planting or preservation. 
The tree canopy fee was developed by converting the wholesale median tree cost in the 
Willamette Valley developed by the PNWISA 5 to a unit canopy cost. According to the 
PNWISA, the median wholesale cost of a 3-inch diameter deciduous tree is $174. T he 
formula developed by Krajicek, et al6 for open grown, broad spreading trees (maximum 
crown width (feet) = 3.183+1.829*DBH (inches)) was then utilized to convert tree diameter 
to canopy diameter. According to the Krajicek formula, a 3-inch diameter tree should have a 
crown width of 8.67 feet or crown area of 59 square feet. These dimensions were confirmed 
as reasonable by staff through several local field samples. Using the median cost o f a 3-inch 
deciduous tree ($17 4) and the crown area of a 3-inch diameter tree (59 square feet), the unit 
canopy cost or tree canopy fee should be $2.95 per square foot. 
This methodology is a reasonable approach for three main reasons. First, tree benefits 
(aesthetic, stormwater management, air quality, etc.) are derived primarily from their 
canopies, so proposing to place a value to tree canopy is appropriate. Second, in the 
proposal, tree canopy is valued using the median wholesale tree cos t only, whereas standard 
tree appraisal is based on the wholesale tree cost plus the cost of tree installation. Finally, 
the Krajicek formula and field samples by staff are based on the maximum crown width-to-
trunk diameter ratio . A typical tree does not have such a high ratio. If the typical ra tio were 
used, the unit canopy cost would increase. 
In addition, staff provided the planning commission a regional comparison of fees in a 
Compara tive Fee-In-Lieu Rates memo for their Februa1y 6, 2012 hearing demonstrating the 
5 Pacific Northwest Chapter of the International Society of ~-\rboricul ture . 2007. Species Ratings for Landscape Tree 
Appraisal. 2"'1 Edition, Silverton, OR: Pacific N orthwest IS~-\ . 
6 Krajicek, ]. E ., K. E. Brinkman, S. F. Gingrich. 1961. Crown Competition- A Measure of Density. Forest Science 
7:35-42. 
Ci ty o f Tigard Urban J <'orc~ Lry Code: RcY i :-\ i on~ I Voh.unc \' I 54 
proposed tree canopy fee is on the low end of the range. 
Finally, the proposed tree canopy fee is not an SDC because it does not meet the definition 
of an SDC in ORS 223.299(4)(a), which states that an SDC "means a reimbursement fee, an 
improvement fee or a combination thereof assessed or collected at the time of increased 
usage of a capital improvement or issuance of a development permit, building permit or 
connection to the capital improvement." 
The tree canopy fee is not an "improvement fee," which is defined in ORS 223.299(2) as a 
"fee for costs associated with capital improvements to be constructed". The tree canopy fee 
is a fee for choosing not to preserve and/ or plant trees to meet established tree canopy 
requirements. 
Staff Recommendation: Do not revise proposed code based on this amendment reguest. 
Amendment: N / A 
48. Ken Gertz, February 6, 2012 
Amendment Request: Appendix 9, page 4-5 UFP - Confused by headings, please clarify. 
Staff Response: Appendix 9 is a Supplemental Arborist Report Template that may be used 
by project arborists when creating urban forestry plans. It converts the text from the Section 
10 of the UFM into a more user friendly summary form. The consultants used the template 
during the peer review phase of the project and found it easy to use. The consultants did not 
raise any issues regarding its clarity nor did they recommend any changes to it in their peer 
review r~_ort (see peer review, UFCR Volume II, page 463). 
Staff Recommendation: Do not revise proposed UFM based on this amendment request. 
Amendment: N /A I 
49. Eric Schultheis, February 6, 2012 
Amendment Request: The code should require that trees planted are the right species for 
the area and spacing is adequate to ensure the future health of planted and preserved trees. 
Staff Response: Section 10 of the UFM contains tree preservation and planting 
specifications to ensure healthy and sustainable trees after the development process is 
complete. Appendices 2 through 5 of the UFM include recommended tree lists to ensure 
appropriate species for a variety of planting situations. 
Staff Recommendation: Do not revise proposed UFM based on this amendment request. 
Amendment: N I A 
--·--------~ 
-
City of Tigard Urban Forestry Code Rc,·isions I Volume V I 55 
50. Dennis Wilson, February 6, 2012 
Amendment Request: T he code should not inhibit future development of a property, nor 
prohibit property owners from removing trees due to personal choice or necessity. 
Staff Response: (the first paragraph of this staff response is from the Tree Canopy Fee ' 
memo, UFCR Volume III, page 15) T he draft canopy requirements have been carefully 
crafted and have undergone a peer review to ensure that they are achievable on the typical 
range of development scenarios in Tigard. For added flexibility, a discretionary review 
option is proposed to allow other green building or development methods (e.g. solar panels, 
green roofs, rain gardens, etc.) in place of planting or preserving the required amount of 
trees. Finally, a fee-in-lieu option is proposed to allow applicants to pay a "tree canopy fee" 
to replace the value of canopy not provided through tree planting or preservation. 
While not part of the proposed development code amendments, it is important to note that 
proposed Chapter 8.14 (Trees that were Required with D evelopment) of the Tigard 
Municipal Code would create a separate process for removing trees after the development 
process is complete. T he existing code requires future owners to amend the original land use 
permit for removing trees that were required with development. Chapter 8.14 would create a 
less costly and less time-consuming process for fu ture owners to remove trees due to 
personal choice or necessity. 
Staff Recommendation: D o not revise proposed code based on this amendment request. 
Amendment: N I A 
51. Sue Beilke, February 6, 2012 
Amendment Request: Require all land use modifications affecting trees to be processed as 
a Type II procedure in order to provide public notice and input. 
Staff Response: O ne of the core G uiding Principles o f the CAC was to allow modifications 
of an Urban Forestry Plan during the course of development through a Type I process so 
that preservation and planting strategies can be easily adapted (see UFCR Volume I, page 
16). Staff committed to the CAC to preserve their G uiding Principles through the legislative 
adoption process unless otherwise directed by the commission or the council. T he 
commission has not directed staff to remove language allowing modifications through a 
Type I process. 
Staff Recommendation: D o not revise proposed code based on this amendment request. 
Amendment: N I A 
Citr of Tiga rd Urban l;orc> tn· Code Rc.,- i>ion> I \ 'olumc \ ' I 5(, 
52. Sue Beilke, February 6, 2012 
Amendment Request: Remove language allowing alternative technologies such as green 
roofs in lieu of tree canopy. 
Staff Response: One of the core Guiding Principles of the CAC was to provide flexibility 
by allowing alternate development proposals such as green roofs or solar instead of 
providing trees (see UFCR Volume I, page 16). Staff committed to the CAC to preserve 
their Guiding Principles through the legislative adoption process unless otherwise directed 
by the Planning Commission or the council. The Planning Commission had not directed 
staff to remove language allowing alternate development proposals. 
Staff Recommendation: Do not revise proposed code based on this amendment request. 
Amendment: N / A 
53. Sue Beilke, February 6, 2012 
Amendment Request: Create special status protections for all native trees, tree groves and 
areas considered to be declining or rare; require permits for their removal. 
Staff Response: The proposed Comprehensive Plan Amendment would establish an 
overlay district for 70 significant tree groves covering 544 acres. The significant tree groves 
are comprised primarily of trees native to the Tigard area. As further explained in the Tree 
Grove ESEE Analysis beginning on UFCR Volume III, page 27, key evaluation criteria in 
the inventory and selection of significant tree groves were grove maturity/ tree size, grove 
size, health/ viability, visibility, screening and buffering, accessibility, rarity, 
educational/ recreational potential, wildlife habitat value and connectivity and the amount of 
existing disturbance. 
The proposed Development Code Amendments in Section 18.790.050.D include regulatory 
incentives and flexible standards for the optional preservation of significant tree groves. 
Optional preservation is consistent with the CAC's Guiding Principles for tree grove 
preservation incentives (see UFCR Volume I, page 17). Staff committed to the CAC to 
preserve their Guiding Principles through the legislative adoption process unless otherwise 
directed by the Planning Commission or City Council. The Planning Commission had not 
directed staff to create additional special status protections for significant tree groves. 
Staff Recommendation: Do not revise proposed code based on this amendment request. 
Amendment: N /A 
-- ---- --------- ------ - - - ----- --- --
54. Sue Beilke, February 6, 2012 
Amendment Request: Amend UFCR to comply with and implement Goal 5 and the 
Tigard Comprehensive Plan Natural Resources chapter. 
Staff Response: As further explained in the staff report for CPA 2011-00004 / DCA 2011-
00002, the proposed UFCR comply with Statewide Planning Goal 5 and the Tigard 
Comprehensive Plan. 
Staff Recommendation: D o not revise proposed code based on this amendment request. 
L__.t\.mef}Qfllent: N I A 
City of Tigard Urban Forestry Code Re,·isions I Volume V I 57 
55. Sue Beilke, February 6, 2012 
Amendment Request: Resubmittal o f comments provided on March 16, 2009, for 
D CA2009-00001 . 
Staff Response: Since these comments are directed at previous Development Code 
Amendments (DCA2009-00001) staff will not respond to them as part o f the proposed 
UFCR. 
Staff Recommendation: D o no t revise proposed code based on this amendment request. 
Amendment: N I A 
56. Robert Ruedy, February 6, 2012 
Amendment Request: Publish public hearing notices in "Cityscape". 
Staff Response: Public hearing dates, times, and locations will be published in the Cityscape 
newsletter as permitted by the Cityscape editor. 
Staff Recommendation: D o not revise proposed code based on this amendment request. 
Amendment: N I A 
57. Robert Ruedy, February 6, 2012 (oral) and February 9, 2012 (written); Ken Gertz, 
February 17, 2012 
Amendment Request: Ruedy: Include standards for "adjacent proper ty line tree 
presen ra tion, hazard mitigation, [and] canopy/ drip-line/ root -infringements." 
Gertz: "How do you propose to deal with tree canopy overlapping lot lines?" 
Staff Response: Section 10, Part 1.] of the UFM, requires trees within 25 feet of the 
development impact area to be included on tree presenration and removal site plan. If 
development impacts occur near the property line, impacted trees on adjacent property 
would be required to be protected by Section 10, Part 1.M and N . 
Section 10, Part 3.M.2, assigns canopy credit for open grown and stand grown trees 
differently. Open grown trees are considered distinct feature s, and the lot with the trunk is 
assigned full credit for the tree canopy area. Stands grown trees are considered cohesive 
units (stands) and the canopy is apportioned based on the tree canopy area directly above the 
corresponding lot. The main purpose for treating open grown and stand grown trees i 
differently is for ease of calculation. Open grown tree canopy can be calculated without 
overreliance on computer software, while stand grown tree canopy can be calculated without 
requiring pro ject arborists to measure the canopies of individual trees within stands. 
Staff Recommendation: D o not revise proposed code based on this amendment request. 
Amendment: N / A 
CitY of 'J'igarJ Urban J.'orcstry Code lh·,·isions I \'olumc \ ' I 5H 
58. Robert Ruedy, February 6, 2012 (oral) and February 9, 2012 (written) 
Amendment Request: Include solar access standards by establishing height and setback 
standards for trees, similar to buildings. 
Staff Response: As detailed in the Urban Forestry Code Revisions and Solar Access memo 
provided to the Planning Commission at their February 6, 2012 meeting, the UFCR is not 
intended to prioritize tree canopy over solar access, nor does it change the existing rights of 
neighboring landowners if a tree is shading an adjoining property. The UFCR does provide 
flexible and incentive-based development standards to allow long-term solar access on a 
project site. This flexibility is provided in an applicant's choice of tree species and planting 
locations, preservation bonuses, a discretionary path and a fee in lieu option. 
Staff Recommendation: Do not revise proposed code based on this amendment request. 
Amendment: N/A 
59. Robert Ruedy, February 9, 2012 
Amendment Request: All property owners should share the costs of citywide tree 
enhancement regulation by adding an additional fee to existing road and sanitary sewer and 
surface water management fee structures and billing processes. 
Staff Response: Urban Forestry Program Funding is part of the Tigard Tree Board's 
ongoing work program and not part of the UFCR project. 
Staff Recommendation: Do not revise proposed code based on this amendment request. 
Amendment: N I A 
60. Robert Ruedy, February 6, 2012 (oral) and February 9, 2012 (written) 
Amendment Request: Add clarifying language regarding how Measure 49 waivers will be 
negated or impacted by the new development code and how compensation will be 
accomplished and measured. 
Staff Response: Measure 49 is not applicable within the Urban Growth Boundary and, 
more specifically, not within the incorporated boundaries of the City of Tigard. 
Staff Recommendation: D o not revise proposed code based on this amendment request. 
L_A.m~~<!f!l.ent: N I A 
-------- --· -- ---- -- ----------- --- ------ ---
61. Robert Ruedy, February 6, 2012 (oral) and February 9, 2012 (written) 
Amendment Request: Add language specifying maintenance responsibilities that will be 
"equitably distributed among ALL COT property owners both public and private." 
Staff Response: Urban Forestry Program Funding is part of the Tigard Tree Board's 
ongoin_g_ work program and not part of the UFCR project. 
Staff Recommendation: Do not revise proposed code based on this amendment request. 
Amendment: N I A 
City o f Tigard Urban Forestry Code RcYisions I Volume V I 59 
62. Robert Ruedy, February 9, 2012 I 
Amendment Request: Please hold the record open for an additional two weeks. ! 
Staff Response: The Planning Commission held the record open after the February 6, 2012, ' 
meeting until February 17, 2012, at 5pm. 
Staff Recommendation: D o not revise proposed code based on this amendment request. 
Amendment: N I A 
63. Robert Ruedy, February 9, 2012 
Amendment Request: Supports other testimony that limits enactment of the UFCR to 
low density, single-family properties and discretionary "case-by-case" implementation for all 
other development. 
Staff Response: The UFCR CAC reached consensus to draft the following achievable 
canopy standards for development that are tiered based on zoning district: 
Tier 1: 40% effective canopy 7 
Tier 2: 33% effective canopyB 
Tier 3: 25% effective canopy9 
For added flexibility, a discretionary review option allows other green building or 
development methods (e.g. solar panels, green roo fs, rain gardens, etc.) in place o f planting 
or preserving the required amount o f trees. Finally, a fee in lieu option allows applicants to 
pay a " tree canopy fee" to replace the value of canopy not provided through tree planting or 
preserva tion (see G uiding Principles, UFCR Volume I, page 15). 
The peer review demonstrates that the standards are achievable without payment of fees in 
lieu or discretionary reviews (see UFCR Volume II, page 463). However, applicants would 
have the option of paying fees or di scretionary review in lieu of providing trees. 
Staff committed to the CAC to preserve their G uiding Principles through the legislative 
adoption process unless otherwise directed by the Planning Commission or the City Council. 
Neither the CAC nor the Planning Commission has recommended limiting the UFCR to low 
density residential di stricts. 
Staff Recommendation: D o no t revise __2!QQ_Osed code based on this amendment request. 
Amendment: N I A 
- R-1, R-2, R-3.5, R-4.5, R-7, and R-12 
R R-25, R-40, C-1", C-C, C-G, C-P, MUE, ~fUE- 1 , ~fUE-2, ~ I UC, ~fUR, and I-P 
~ ?\fU-CBD, J\fUC-1, 1-L, 1-H, and schools (18.130.0500)) 
City oi"TigarJ Urban l 'o rc>~rr CoJc: R,.,-isions I \ 'olumc \ ' I (,() 
64. Robert Ruedy, February 9, 2012 
Amendment Request: "Green Roof' options should be accepted in lieu of trees. 
Staff Response: The proposed Discretionary Urban Forestry Plan Review option in Section 
18.790.040 would allow applicants to propose the use of green roofs in lieu of trees through 
a Type III approval process. 
Staff Recommendation: Do not revise proposed code based on this amendment request. 
Amendment: N I A 
65. Gretchen Fehrenbacher, February 10, 2012 
Amendment Request: Requests no preservation requirement and no canopy requirement 
as her property is served with nearby open space (within Vz mile). 
Staff Response: Preservation is not required by the proposed code. Tiered canopy 
standards are proposed that can be met through any combination of planting new trees or 
preserving existing trees. 
If trees are not feasible or desirable, a discretionary review option is proposed to allow other 
green building or development methods (e.g. solar panels, green roofs, rain gardens, etc.) in 
place of providing the required amount of trees. Also, a fee in lieu option is proposed to 
allow applicants to pay a " tree canopy fee" to replace the value of canopy not provided (see 
Guiding Principles, UFCR Volume I, page 1 5). 
Staff committed to the CAC to preserve their Guiding Principles through the legislative 
adoption process unless otherwise directed by Planning Commission or the City Council. 
Neither the CAC nor the Planning Commission has recommended waiving the UFCR when 
property is served by nearby open space. 
Staff Recommendation: Do not revise proposed code based on this amendment request. 
Amendment: N I A 
City o f Tigard Urban l'orcm y Code R(;,·isions I Volume \' I (,1 
66. Stone Bridge Homes NW, February 14, 2012 
Amendment Request: Revise the code to provide more simplicity and brevity, and allow 
homeowners and landscape architects to perform more work rather than arborists. 
Staff Response: The core code sections o f the UFCR in title 8 and Chapter 18.790 are 
relatively simple and brief. Much o f the length in UFCR Volume II comes from the 
commentary pages, ensuring consistency between related code chapters and strike- through 
of existing tex t. 
Title 8 does not require arborists except for the technical tasks of tree risk assessment and 
thinning stands of trees to improve stand health. 
Chapter 18.790 continues the current code requirement for arborists to prepare Urban 
Forestry Plans for development. 
T he UFM includes more detailed specifications for implementing the code. H owever, the 
specifications largely document the city's current operating procedures and are intended to 
provide more certainly regarding city requirements. If the city were to provide less detail, 
disputes over interpretation would likely result after implementation. Lack o f certainty and 
clear expectations are common complaints with the existing code, and the UFM is intended 
to address these issues. 
Staff Recommendation: D o no t revise proposed code based on this amendment request. 
Amendment: N / A 
67. Harris McMonagle Associates, February 15, 2012 
Amendment Request: "The mention o f the director having veto power if he/ she does not 
like what they see in the development pattern, this is way too much subjective power to be 
placed in anyone." 
Staff Response: Section 18.790.020.1\ requires urban forestry plans for certain Type II and I 
Type III land use reviews. Section 18.390.020.B says that Type II reviews contain some 
discretionary criteria and Type III reviews contain predominantly discretionary criteria. 
Section 18.790.050 (Flexible Standards for Tree Planting and Preservation) grants the 
director authority to deviate from standard code requirements such as lot size, setbacks, 
sidewalk location, parking, etc., to facilitate the planting and preservation of trees. H owever, 
if the director makes a finding that deviating from the standard application of the code 
presents an unreasonable risk to public health, safety or welfare the director may deny the 
request. As stated above, the director has the authority to exercise such discretion as part of 
Type II and III land use reviews. 
Staff Recommendation: D o not revise proposed code based on this amendment request. 
Amendment: N /A 
City ofTigarJ Llrban J.'ore,try CoJc Rc,- i, ion' I \ 'olumc \ ' I 62 
68. Harris McMonagle Associates, February 15, 2012 
Amendment Request: Revise the canopy calculation formula to one based on front and 
back yard area, rather than the entire lot. 
Staff Response: The formula for calculating effective tree canopy in Section 10, Part 3.M of 
the UFM, is designed for the overall development site with a separate minimum per lot 
requirement. The calculations were tested during the peer review phase of the project and 
were found to be achievable resulting in a reasonable balance between trees and open space 
(see UFCR Volume II, page 463). 
If the formula for calculating effective canopy were revised, the revised formula should be 
peer reviewed as well. However, since the proposed formula has already been supported 
through the peer reviewed, staff does not recommending expending additional time and 
resources testing a new methodology. 
Staff Recommendation: Do not revise proposed code based on this amendment request. 
Amendment: N I A 
69. Harris McMona~le Associates, February 15, 2012 
Amendment Request: Allow adjustments to standards to allow the preservation of 
existing trees. 
Staff Response: Section 18.790.050 of the proposed code allows adjustments to standards 
for the preservation of existing trees. 
Staff Recommendation: Do not revise proposed code based on this amendment request. 
Amendment: N I A 
70. JT Smith Companies, February 15, 2012 
Amendment Request: Develop a case study and in-depth review of the feasibility of 
proposed canopy goals. 
Staff Response: A case study and in-depth review of the feasibility of the proposed tree 
canopy requirements was completed through the peer review phase of the project (see 
UFCR Volume II, page 463). 
Staff Recommendation: Do not revise proposed code based on this amendment request. 
Amendment: N I A 
City o f Tigard Urban Forestry Code RcY isions I Volume \' I 63 
71. John Frewing, February 17, 2012 
Amendment Request: "The tree values memo (Urban Forestry Annotated Bibliography) 
at page 1 o f Volume 3 is significantly deficient in not containing any papers which show the 
vital relationship between trees and wildlife ... I ask that you request staff to prepare an 
amendment to the present proposal which would add appropriate bibliography to the 
legislative basis for Tigard 's ~osal. " 
Staff Response: T he tree values memo is based on the annotated bibliography for the 
findings for adoption of the Urban Forest section o f the Comprehensive Plan (CP A2008-
00002). As reflected in the tree values memo, the primary reasons for adopting the Urban 
Forest section o f the Comprehensive Plan and the resulting Urban Foresu-y Standards for 
D evelopment (see UFCR Volume II, pages 135 to 341) are stormwater, shading, property 
value, public health and sa fety, air quality, carbon sequestration, social and other non-wildlife 
benefits of trees. 
T he exception are the Tree Grove Preservation Incentives in Section 18.790.050.D (see 
UFCR Volume II, page 317), which are being adopted specifically because of the wildlife 
benefits provided by trees. T he Tree Grove ESEE Analysis (see UFCR Volume III, page 
17) details the reasons for adopting flexible standards and incentives and highlights wildlife 
benefits. 
It is not necessary to include wildlife benefits of trees in the tree values memo because the 
UFCR is being adopted primarily for o ther reasons. The ESEE analysis highlights the 
wildlife benefits provided by trees for that portion of the UFCR that is being adopted 
specifically for that purpose. 
Staff Recommendation: D o not revise the tree values memo based on this amendment 
request. 
Amendment: N I A 
City of Tigard Urban I ;orcs trr Code Rc,·isions I \" olumc \ ' I (,.j 
72. John Frewing, February 17, 2012 
Amendment Request: The ESEE analysis needs editorial corrections to incorporate 
correct references to the Tigard Development Code, and substantive updating to Site #62 
and Grove # 71. 
Staff Response: In reviewing the ESEE analysis, staff recommends correcting some 
scrivener's errors to ensure accurate references to code chapters. 
Staff also recommends revising the boundaries of inventoried Tree Groves #38 and #62 in 
the Significant Tree Grove Map since portions o f these groves have been removed since the 
original inventory was completed in summer 2010. The Significant Tree Grove Map may be 
adjusted because the legislative adoption process is not yet completed. 
Staff will not be revising the boundaries of Tree Grove # 71 in the Significant Tree Grove 
Map because no trees have been removed since the original inventory was completed in 
summer 2010. 
Finally, staff will not be revising the descriptions for Tree Groves #62 and # 71 because they 
are derived from field notes provided by the consultant at the time of the inventory and do 
not affect the boundaries or preservation incentives for these groves (see UFCR Volume III, 
pages 125, 170 and 177). 
Staff Recommendation: Revise the proposed ESEE analysis and Significant Tree Grove 
Map based on this amendment request. 
Amendment: (note: the full text from the ESEE analysis associated with these corrected 
scrivener's errors is not provided) 
Change "18. 70" to "18. 790" 
Change "18. 770" to "18. 790" 
Change "18. 7 50" to "18. 790" 
Change "18. 7 55" to "18. 77 5" 
(see UFCR Volume III, page 22) 
(see UFCR Volume III, pages 33 and 83) 
(see UFCR Volume III, page 47) 
(see UFCR Volume III, pages 34 (4 times), 47 and 64) 
(note: the amended Significant Tree Grove Map is attached and provided 
with the staff report for the April 16, 2012 Planning Commission meeting) 
Adjust boundaries of inventoried Tree Groves #38 and #62 as shown on the attached 
Significant Tree Grove Map. 
City o f Tigard Urban l'orestry Code Re,·isions I Volume \ ' I 65 
73. John Frewing, February 17, 2012 
Amendment Request: "The ESEE introduction (page 17, Vol III) doesn't reflect reality in 
saying that the tree grove preservation program was identified as a " top priority" o f the 
community . . . .in the statistically valid survey (beginning page 285, Vol III), among the open 
ended input by the community, there was not O NE suggestion that a tree grove program 
was needed, whereas there were many statements that the major interest was in preserving 
existing trees generally ... I ask that you reques t staff to include text recognizing the greater 
importance given to tree preservation over tree groves by Tigard citizens in the legislative 
basis for this proposal. " 
Staff Response: The ESEE introduction is an accurate summary o f community input (see 
UFCR Volume III, page 17). T he Urban Forestry Master Plan identified the development of 
a tree grove protection program as one of six implementation goals for the city (see UFCR 
Volume III, pages 253, 257 and 267-268). An extensive public process gleaned information 
from the community that was used to create these implementation goals, including a 
statistically valid survey. Survey question REG6 directly asked respondents their preferred 
focus of po tential new tree protection measures. Focusing on large groves received a 55.25% 
response rate, while focusing on individual trees received 28.25% (see UFCR Volume III, 
page 298). 
The ESEE analysis is specific to significant tree groves subject to Statewide Planning Goal 5 
rule requirements. Individual trees are not addressed in the ESEE because individual trees 
are not considered goal 5 resources. 
Staff Recommendation: D o not revise the proposed ESEE analysis based on this 
amendment request. 
Amendment: N I A 
74. John Frewing, February 17, 2012 
Amendment Request: "The staff report should [be amended and] explicitly state that the 
UFM is no t a code amendment and that as I noted in an earlier comment, the city has 
"unfettered discretion" in modifying the UFM. H ence, it cannot be relied on by citizens as 
enforceable regulation for tree protection and urban forest enhancement." 
Staff Response: T he staff report explicitly describes the UFM in Section III, Background 
Information of the staff report for CPA 2011 -00004I D CA 2011 -00002. 
Changes to administrative rules in the UFM require public no tice and opportunity for 
appeal, as governed by Section 2.04.070 of the Tigard Municipal Code. Therefore, the city 
does no t have unfettered discretion with regards to the administrative rules in the UFM. 
Staff Recommendation: D o not revise the staff report based on this amendment request. 
Amendment: N I A 
City of'J'iganl Urban l'orcstry Code Rc,-isions I \ 'olumc \ ' I (,(, 
I 
I 
! 
75. John Frewing, February 17, 2012 
Amendment Request: " [have] the code provide a threshold-based rule applying the urban 
forest regulations to maj or redevelopments." 
Staff Response: The proposed code applies the Urban Forestry Plan requirements to major 
development projects that reach the thresholds requiring Type II and III land use permits 
listed in Section 18. 790.020.A. 
Staff Recommendation: Do not revise proposed code based on this amendment request. 
Amendment: N I A 
76. John Frewing, February 17, 2012 
Amendment Request: E ffective canopy area should be calculated for the Development 
Impact Area, and not the overall site. 
Staff Response: The formula for calculating effective tree canopy in Section 10, Part 3.M of 
the UFM, are designed for the overall development site with a separate minimum per lot 
requirement. The calculations were tested during the peer review phase of the project and 
were found to be achievable, resulting in a reasonable balance between trees and open space 
(see UFCR Volume II, page 463). 
If the formula for calculating effective canopy were revised, the revised formula should be 
peer reviewed as well. However, since the proposed formula has already been supported 
through the peer reviewed, staff does not recommending expending additional time and 
resources testing a new methodology. 
Staff Recommendation: Do not revise proposed code based on this amendment request. 
Amendment: N I A 
City of Tigard Urban Forestry Code Rc,·isions I Volume\' I 67 
77.John Frewing, February 17,2012 
Amendment Request: "at 18.790.070.B.1.b, B.2.c, and B.3.b ... the requirement regarding 
urban forest modification is worded such that it is only required that a modified plan and 
justification be submitted before changing the site plantings - review and approval comes 
later, perhaps too late. I believe better wording would be "Submitted for review and 
approval prior to (removal, planting, modification)" . 
Staff Response: In reviewing the code sections referenced above, staff agrees that revising 
the sentence structure for clarification would be beneficial. 
Staff Recommendation: Revise proposed code based on this amendment request. 
Amendment: (18. 790.070.B.1) 
"b. A revised tree canopy site plan and supplemental arborist report 
are submitted for review and approval prior to removal fof feview and appwval that reflect 
the proposed changes to the previously approved Urban Forestry Plan= -aftcl T he revised tree 
canopy site plan and Sllpplemental arborist report shall demonstrate how eid'ief the effective 
tree canopy cover requirements in Section 10, part 3 o f the UFM will be provided by the 
pt"epesed eemeiftat:ieft ef tree planting, -aftcl preservation~ and/ or; payment o f a tree canopy 
fee in lieu o f planting or preservation. Vv'ill ee pt"O'V~ided te make up the diffefeftee eet\.veeft 
the pt"epesed effeet:ive tt:ee eaftepy eevef aftd the effeet:it"e tt:ee eaftepy eevef fequi:femeftts 
ift Seet:ieft 10, pan 3, ef the UFM fof the let ef tt:aet whefe the medifieat:ieft is prepesed." 
(18. 790.070.B.2) 
" c. A revised tree canopy site plan and supplemental arborist report 
are submitted for review and approval prior to planting fof fevievv· and appre val that reflect 
the proposed changes to the previously approved Urban Forestry Plan." 
(18. 790.070.B.3) 
"b. A revised tree preservation and removal site plan, tree canopy 
site plan and supplemental arborist report are submitted for review and approval prior to 
modification o f the tree pro tection fencing fof feviev;; aftd appwval that reflect the proposed 
modifications to the previously approved Urban Forestry Plan." 
City ol Tigard Urban J.'orc, trr Code RtTi,iom I \ 'olumc \ ' I (,H 
78. John Frewing, February 17, 2012 
Amendment Request: Change the structure of the code to comply with Oregon land use 
law. "I believe, the proposed structure of Tigard's proposal (substantive material displaced 
to an administrative rule) violates Oregon's land use law. ORS 197.17 5(2)(b) regarding city 
planning responsibilities requires Tigard to "enact land use regulations to implement their 
comprehensive plans" ... the law refers to regulations, not administrative rules. ORS 227.173 
regarding the basis for land use decisions states that "approval or denial" of a discretionary 
permit application shall be based on standards and criteria set forth in development 
ordinances." ORS 197.805 states that the Land Use Board of Appeals shall have exclusive 
jurisdiction to review any land use decision. By structuring its material as proposed, Tigard 
prejudices/ eliminates my substantial rights to a land use decision under Oregon land use 
law." 
Staff Response: Section 18.790.030 (Urban Forestry Plan Requirements) requires applicants 
to demonstrate technical standards in the UFM are met. If someone believes an Urban 
Forestry Plan does not meet the technical standards in the UFM, they may appeal the 
decision to the Land Use Board of Appeals. Referencing technical standards in development 
codes is a common practice such as when performing wetland delineations, traffic studies, 
road and utility construction, etc. The proposed code complies with Oregon land use laws. 
Staff Recommendation: Do not revise _proposed code based on this amendment request. 
Amendment: N /A 
- - ----------- - - - - - ·-------
79. John Frewing, February 17, 2012; Mike McElevey, February 21, 2012 
Amendment Request: Frewing: Raise the equivalent Tigard fee from $87 per caliper inch 
to $150 per caliper inch for mitigation and fee-in-lieu trees. 
McElevey: Request the fee-in-lieu be maximized "to a point where developers actually make 
a few decisions in favor of saving large trees." 
Staff Response: The proposed methodology for the tree canopy fee is based on the 
wholesale median tree cost in the Willamette Valley developed by the PNWISA (see UFCR 
Volume III, page 15). The requested increased in the fee would not be based on the 
proposed methodology. 
Staff Recommendation: Do not revise proposed code based on this amendment request. 
Amendment: N /A 
City of Tigard Urban Forestry Code RcYisions I Volume V I 69 
80. Ken Gertz, February 17, 2012 
Amendment Request: Add a language at the beginning of the code stating "that regardless 
of a tree plan requirement, Private Property should be allowed to develop to its stated 
potential". 
Staff Response: The proposed Urban Forestry Plan requirements can be met through any 
combination of planting new trees or preserving existing trees. 
If trees are not feasible or desirable, a discretionary review option is proposed to allow o ther 
green building or development methods (e.g. solar panels, green roofs, rain gardens, etc.) in 
place of providing the required amount of trees. Also, a fee in lieu option is proposed to 
allow applicants to pay a "tree canopy fee" to replace the value of canopy not provided (see 
Guiding Principles, UFCR Volume I, page 15). 
The Urban Forestry Plan requirements have been designed to provide maximum flexibility 
so that property can be developed as otherwise allowed by code. It is not necessary to add 
the language recommended in this amendment request. 
Staff Recommendation: Do not revise proposed code based on this amendment request. 
Amendment: N I A 
81. Ken Gertz, February 17, 2012 
Amendment Request: State in the code that canopy area is to be based on mature canopy. 
Staff Response: Section 10, Part 3.M.c and d specify that planted trees receive credit based 
on their mature canopy area when calculating effective tree canopy. 
Staff Recommendation: Do not revise proposed code based on this amendment request. 
Amendment: N I A 
82. Ken Gertz, February 17, 2012 
Amendment Request: Revisit "tree boxes" to "determine when exactly they should be 
required." 
Staff Response: Soil volume requirements apply to street trees and parking lot trees per 
Sections 18.745.040.A.4 and 18.745.050.E .a.4 respectively. The Guiding Principles states that 
these tree types should be required to meet soil volume requirements because they often 
have limited access to sufficient soil to support their function of providing canopy over 
impervious surfaces (see Guiding Principles, UFCR Volume I, page 15). 
Staff committed to the CAC to preserve their Guiding Principles through the legislative 
adoption process unless otherwise directed by the Planning Commission or the C. Planning 
Commission had not directed staff to revisit soil volume requirements. 
Staff Recommendation: Do no t revise proposed code based on this amendment request. 
Amendment: N I A 
CitY of Tigard Urban l'orc,try Code Rc,-i,iom I \'olumc \ ' I 70 
83. Ken Gertz, February 17, 2012 
Amendment Request: Include language specifying that mitigation funds be returned on a 
lot/ tract by lot/ tract basis, rather than a lump sum. 
Staff Response: Section 11 Part 2.D of the UFM specifies that the tree establishment bond 
amount will be correspondingly reduced on a lot/ tract by lot/ tract basis. 
Staff Recommendation: Do not revise proposed code based on this amendment request. 
Amendment: N /A 
84. Mike McElevey, February 21, 2012 
Amendment Request: Provide leeway for homeowners to maintain and remove trees 
where unsafe conditions exist. 
Staff Response: Chapter 8.04 (Tree Permit Procedures) of the proposed code would 
establish a permit process that is separate from the land use process for future owners to 
remove trees where unsafe conditions exist. The existing code requires future owners to 
revise the original land use permit to remove trees that were required with development, 
while the proposed code would create a more cost and time efficient process for removing 
trees after the land use process is complete. 
Staff Recommendation: Do not revise proposed code based on this amendment request. 
Amendment: N /A 
85. Mike McElevey, February 21, 2012 
Amendment Request: " If property owners are expected to undergo expense and 
inconvenience for the enjoyment of the general public, they should be compensated." 
Staff Response: Urban Forestry Program Funding is part of the Tigard Tree Board's 
ongoing work program and not part of the UFCR project. 
Staff Recommendation: Do not revise proposed code based on this amendment request. 
Am~ndment: N /A 
City of Tigard Urban Forestry Code Rc,·isions I Volume\' I 71 

Urban Forestry Code Revisions 
Outstanding Issues for the Urban 
Forestry Code Revisions 
l.ity of Tigard Urban Forestry Code RcYisions I Volume V I 73 
.
.,. 
r-
To: 
From: 
Re: 
D ate: 
City ofTigard 
Memorandum 
City Council 
Todd Prager, Associate Planner / Arborist 
Outstanding Issues for the Urban Forestry Code Revisions 
June 25, 2012 
At the April 16, 2011 , Planning Commission meeting, the commission reviewed and received 
additional testimony on the Urban Forestry Code Revisions amendment requests, 
considered staffs recommended amendments and further deliberated on the amendment 
requests and staffs recommendations. The commission decided to continue the hearing until 
May 7, 2012, for additional tes timony and deliberation on the following three outstanding 
tssues: 
1. Application o f the proposed code on small residential lots Qess than 5000 sq. ft.) and 
small residential developments (Minor Land Partitions). 
2. Legal requirements for property owners to maintain trees that were planted by 
developers during the two year establishment period. 
3. Information on the tree canopy fee in lieu option. 
Staff provided for the commission below additional background for each issue, optional 
amendments to address each issue and staff s recommended amendment option. Also 
included are the additional amendments from the April16, 2012, meeting that the 
commission indicated comfort with, which include bonus credits for native trees, and minor 
text and map amendments for clarification purposes. 
T he text amendments for the outstanding issues are in the "Optional Amendments for the 
Outstanding Issues" section of this document. T he text amendment for the additional 
amendments are in the "Additional Amendments from the April 16, 2012, Planning 
Commission Meeting" section. Staff determined the exact text that was forwarded to City 
Council, based on the policy choices made by the Planning Commission. 
T he Planning Commission selected the staff recommended options as their preferred option 
for each o f the outstanding issues below and forwarded their recommendation to City 
Council on the Urban Foresu-y Code Revisions at their May 7, 2012, meeting. Also included 
in their recommendation to City Council were all of the amendments from the "Additional 
City of Ti~-,'ll ru Urban Jo'orcm y Code Re,·isions I Volume V I 75 
Amendments from the April 16, 2012 Planning Commission Meeting" section o f this 
document. 
All references to project materials in the following are to the volumes considered by the 
Planning Commission, not to the volumes under consideration by the City Council. 
City of Tigard Urban l'orcstry Code Rc,·isions I \'olumc \ ' I 7(, 
Issue 1: Application of the proposed code on small residential lots (less than 5000 sq. 
ft.) and small residential developments (Minor Land Partitions). 
The peer review results demonstrate that the proposed effective tree canopy requirements 
are achievable on the range of sites that were tested (see UFCR Volume II, page 463). Two 
of the residential sites tested have R-4.5 and R-7 zoning, with minimum lot sizes of 7,500 sq. 
ft. and 5,000 sq. ft. respectively, and met the Tier 1 (40%) effective tree canopy 
requirements. The other residential site tested has R-25 equivalent zoning, with lot sizes less 
than 3,000 sq. ft., and met the Tier 2 (33%) effective tree canopy requirement. 
The proposed code places the R-12 district, which has a minimum lot size requirement of 
3,050 sq. ft., in Tier 1. Since an R-12 site was not tested through the peer review, the 
commission could move the R-12 district to Tier 2 to be conservative, since the R-25 site 
(which has smaller lots) was able to meet the requirements. 
1.A. Options for the R -12 Zone Tier: 
1. Move the R-12 district into Tier 2 (staff recommended option). 
2. Keep the R -12 district in Tier 1. 
In addition, there has been discussion of the challenges of the 15% per lot minimum 
effective tree canopy requirement on small residential lots 0ess than 5000 sq. ft.). Due to the 
more limited street frontage of small residential lots, it is more difficult to place street trees 
for each lot to meet the per lot minimum. Eliminating the per lot minimum for small 
residential lots would increase flexibility. There would still likely be an incentive to plant 
larger stature street trees (which is the commission's preference) because selecting larger 
growing species to meet the requirements would be less expensive than planting additional 
trees on the lots. If the per lot minimum is eliminated for small residential lots, staff 
recommends eliminating it for commercial, mixed use, and industrial development as well, 
since these sites are often comprised of unique lots that could present challenges when 
meeting the requirements with limited resulting benefits. This could be accomplished by 
eliminating the 15% per lot minimum for Tier 2 and 3. 
Alternatively, the commission could consider eliminating the per lot minimum in all districts. 
This would address testimony received regarding the unique challenges presented by some lots 
or tracts, even in the low density residential districts. However, this could result in unintended 
consequences, such as smaller stature and/ or inconsistent street tree planting when meeting the 
minimum tree canopy requirement for the overall development site. 
1.B. Options for the Per Lot Minimum Effective Tree Canopy Requirement: 
1. Eliminate the 15% per lot minimum for Tier 2 and 3 districts only (staff 
recommended option). 
2. Eliminate the 15% per lot minimum for all districts. 
3. Keep the 15% per lot minimum for all districts. 
City of Tigard Urban Forestry Code Re,·isions I Volume V I 77 
T he peer review results do demonstrate that for residential sites, the effective tree canopy 
requirements can be met primarily through the strategic use of larger stature street trees (see 
UFCR Volume II, page 463). 
T he incentive to maximize street tree canopy is deliberate as street trees are scientifically proven 
to have particularly high benefit to cost ratios in urban areas (see UFCR Volume III, page 1 ). 
Street trees are increasingly viewed as part o f the city's "green infras tructure", as essential as 
o ther infras tructure elements such as street lights and storm drains. However, for street trees to 
achieve their po tential canopy growth (and trees in general), adequate soil resources and proper 
planting methods are critical. 
T he proposed code places a high value on the role of arborists in designing and implementing 
the conditions for sustainable urban tree canopy, which include providing adequate soil 
volumes. In some cases, a landscape architect is required if alternative techniques are utilized, 
such as structural soil volumes under pavement. For general tree planting on sites, the project 
arborist is required to evaluate soils and recommend amendments if needed to support tree 
growth. The project arborist is also responsible for specifying and monitoring the tree 
protection fencing for trees to be preserved, which include neighboring trees close to the 
property lines. 
Staff acknowledges that requiring arborists adds cost to projects, but it is consistent with the 
direction o f the urban foresu-y code revisions: to distribute development costs more equitably 
(rather than only requiring arborist for pro jects with existing trees) and to focus on es tablishing 
healthy future canopy (rather than only penalties for tree removal). As expressed by some 
members o f the commission, there is value in consistent application of the urban forestry code 
revisions across residential zones in order to support the goals of the Urban Forestry Master 
Plan. That being said, the following options are available to the commission. 
l.C. Options for Addressing Urban Forestry Plan Requirements for Residential Zones: 
1. Continue to require urban forestry plans for all residential districts (staff recommended 
option). 
2. D o not require urban forestry plans for residential districts that allow small lots Qess than 
5,000 sq. ft. lot size allowed) which are the R-12 and R-25 districts. 
Plans developed by a certified arborist for the preservation and planting o f trees are currently 
required for small residential developments (Minor Land Partitions) . T he proposed code would 
continue to require plans developed by a certified arborist for small residential developments. 
Staff analysis of the buildable lands inventory found that the largest share o f buildable sites in 
Tigard is between 10,000 sq. ft. and 1 acre. T his means that Minor Land Partitions likely 
represent a significant share o f future residential development in Tigard . 
T he commission expressed some concern regarding the cost of developing urban foresu-y plans. 
T he cost estimated by sta ff to develop and implement an urban forestry plan for a Minor Land 
Cit\· of T igard Urban Fo rcs rrr Code RcY isions I \ 'o lumc \ ' I 7H 
Partition based on interviews with local arborists is between $4,000 and $5,000 (includes 
inventory field work, site plan, arborist report, revisions based on city review, and 
implementation inspections). However, costs associated with the existing code for tree removal 
mitigation can reach $30,000 for a Minor Land Partition (this does not include the cost to 
develop a tree plan). 
Since project arborists are already required to develop urban forestry plans for Minor Land 
Partitions, Minor Land Partitions are likely to represent a significant share of future residential 
development. The costs associated with urban forestry plans will be less in many circumstances 
than existing costs, due to the elimination of mitigation. Staff recommends continuing to require 
urban forestry plans for Minor Land Partitions. However, the commission does have the option 
of not requiring urban forestry plans for Minor Land Partitions. 
l .D. Options for Addressing Urban Forestry Plan Requirements for Minor Land Partitions: 
1. Continue to require urban forestry plans for Minor Land Partitions (staff recommended 
option). 
2. D o not require urban forestry plans for Minor Land Partitions. 
Staff has identified an opportunity for creating efficiencies when developing urban forestry 
plans, while ensuring high quality design and implementation. Arborists and landscape architects 
have different skill sets. While arborists have expertise with regards to tree biology and growth, 
landscape architects have expertise with design, soil amendments and creating construction 
drawings. For projects that rely on street trees with structural soils to meet their requirements, it 
would reduce costs if the landscape architect could also complete the urban forestry plan 
(without requiring a certified arborist). Consideration should be given to allowing either 
landscape architects or arborists to develop urban forestry plans, to allow these efficiencies to 
occur. 
l.E. Options for Developing Urban Forestry Plans: 
1. Allow landscape architects, in addition to arborists, to develop urban forestry plans (staff 
recommended option). 
2. Continue to allow only arborists to develop urban forestry plans. 
Issue 2: Legal requirements for property owners to maintain trees that were planted 
by developers during the two year establishment period. 
The Planning Commission asked for input from the City Attorney regarding the legal 
requirements for property owners to maintain trees that were planted by developers during the 
two year establishment period. The concern raised by the commission was whether property 
owners could remove trees that were planted by developers. 
\s suggested by the commission, the City Attorney agreed the developer could contractually 
obligate a property owner to maintain or allow for the maintenance of trees as part of the 
purchase and sale agreement. In addition, section 6.02.180 (Property Development and 
City of Tigard Urban Forestry Code Rc\'isions I \' olume \' I 79 
Maintenance Requirements, Urban Forestry) would prohibit the unauthorized removal of trees 
during the establishment period. If a property owner were to remove a tree, they would be 
subject to penalties in Chapter 1.16 (Civil Infractions). 
Because adequate safeguards are in place, staff is not proposing changes regarding the two year 
establishment period. 
Issue 3: Information on the tree canopy fee in lieu option. 
T he Planning Commission requested additional information on the proposed tree canopy 
fee in lieu methodology. Much of this information is from the Tree Canopy Fee Memo (see 
UFCR, Volume III, page 15). 
The methodology for the proposed tree canopy fee was developed by converting the 
wholesale median tree cost in the Willamette Valley, developed by the PNWISA to a unit 
canopy cost. According to the PNWISA, the median wholesale cost of a 3-inch diameter 
deciduous tree is $174. T he formula developed by Krajicek, et al. for open grown, broad 
spreading trees (maximum crown width (feet) = 3.1 83+1.829*DBH (inches)) was then 
utilized to convert tree diameter to canopy diameter. According to the Krajicek formula, a 
3-inch diameter tree should have a crown width of 8.67 feet or crown area o f 59 square feet. 
These dimensions were confirmed as reasonable by staff through several local fteld samples. 
Using the median cost o f a 3-inch deciduous tree ($174) and the crown area of a 3-inch 
diameter tree (59 square feet), the unit canopy cost or tree canopy fee should be $2.95 per 
square foot. 
T his methodology is a reasonable approach for three main reasons. First, tree benefits 
(aesthetic, stormwater management, air quality, etc.) are derived primarily from their 
canopies, so proposing to place a value to tree canopy is appropriate. Second, in the 
proposal, tree canopy is valued using the median wholesale tree cost only, whereas standard 
tree appraisal is based on the wholesale tree cost, plus the cost o f tree installation. Finally, 
the Krajicek formula and field samples by staff are based on the maximum crown width-to-
trunk diameter ratio . A typical tree does not have such a high ratio. If the typical ratio were 
used, the unit canopy cost would increase. 
As shown in the "Comparative Fee-in-Lieu Rates" memo from the February 6, 2012 
Planning Commission meeting, the proposed tree canopy fee in lieu would be low when 
compared with other fees in the region. Also, the tree canopy fee in lieu in the proposed 
code is lower than the mitigation fee in lieu in the existing code. Consider the following: 
Ci ty of Tigard Urban l;orcstry Code RcYisions I \ 'olumc \ ' I 80 
Existing Code Proposed Code 
Mitigation Based Canopy Based 
$12S/ caliper inch $2.9S/ sq. ft. 
Fee for 12" DBH Tree = $1,SOO Fee for 12" DBH Tree = $1,463 1 
While staff is unclear on the specific methodology of the alternate fee in lieu proposed in 
public testimony, significantly reducing the fee would significantly undervalue tree canopy. 
This would likely reduce the incentive for applicants to plant or preserve trees, resulting in 
increased payments to the city who would then be obligated to utilize the funds. 
The issue raised by the commission is whether the city is interested in potentially increasing 
revenue by lowering the fee in lieu (so applicants pay the city rather than plant or preserve 
trees with development). Staffs perspective is that the purpose of the fee is to create an 
incentive to plant and preserve trees on private property, rather than to create a revenue 
source for the city. However, if applicants choose to pay a fee in lieu, the fee should be 
designed to capture the full value of canopy that will not be provided for the community. 
This is consistent with the direction of the Citizen Advisory Committee. 
However, if the Planning Commission would like to encourage payment of fees in lieu of 
tree planting or preservation, the cost of the tree canopy fee could be reduced. If the tree 
canopy fee were reduced by half, then SO% of the canopy value would be borne by the 
applicant with the other SO% borne by the community. 
3.A. Options for the Tree Canopy Fee In Lieu: 
1. Continue to use the tree canopy fee in lieu methodology that captures the full value of 
tree canopy (currently $2.9S per sq. ft. of tree canopy which is equivalent to $174 for a 3-
inch caliper tree, this is the staff recommended option). 
2. Revise the tree canopy fee in lieu methodology to capture one half the value of tree 
canopy (currently $1.47 per sq. ft. of tree canopy which is equivalent to $87 for a 3-inch 
caliper tree). 
Amendments from the April16, 2012, Planning Commission Meeting 
The Planning Commission indicated support for the following additional amendments at the 
April16, 2012, meeting: 
1. Minor text amendment to the summary heading of section 18.790.030.A. 
2. Reduce the per lot effective tree canopy cover requirement to 1 S% in Chapter 18.790 
and the Urban Forestry Manual. 
1 DBH converted to canopy using tl1e Krajicek formula 
City of Tigard Urban l'orcstry Code Rc,·isions I Volume \' I 81 
3. Correct scrivener's errors in section 18.790.030.C. 
4. Correct scrivener's errors in ESEE and boundaries of significant tree groves #38 and 
#62 to reflect changes due to recent tree removal. 
5. Minor text amendment to clarify the review and approval process in sections 
18.790.070.B.1-3. 
6. Grant 1.25x bonus credit for planting native trees. 
7. Minor text amendment to remove a repetitive approval criterion for tree removal permit 
requirements in sensitive lands. 
Staff has included the amendments towards the end of this document in the "Additional 
Amendments from the April 16, 2012, Planning Commission Meeting" section. 
CitY of Tigard Urban l;orcstn· Code RcYisions I \ 'olumc \ ' I S2 
Optional Amendments for the Outstanding Issues 
Issue l.A: Options for the R-12 Zone Tier 
Option 1: Move the R-12 Zone into T ier 2 (staff recommended optio n). 
Non Land Use Amendments: (Urban Fom·try Manual Sedion 10, Part 3.N (Urban Fom·try 
Plan- Supplemental A rboriJt Report RequirementJ)) 
N. T he standard percentage of effective tree canopy cover for the overall development site shall 
be at least: 
1. 40 percent for Lo<v Density Residential snd Medit:tffl Den:siry Residential (R-1, R-2, 
R-3.5, R-4.5, and R-7, snd R 12) districts, except for schools (18.130.0500)); 
2. 33 percent for Medittm High Densiey Residential snd I Iigh Densiry Residential E& 
12. R-25~ ftfttl R-40), :t>Jeighborhood Gommereisl, Gommttn:ity Gommet·eisl, Genersl 
Gommereisl snd Professions}lAdminisff'ative Gommereisl ~C-N, C-C, C-G, ftfttl C-
P), M~ed ldse Employmen~, M~ed Yse Employmen~ 1, M~<ed Yse Employmen~ 2, 
:Mixed Yse Gommereisl and Mixed Ysed Residential (MUE, MUE-1, MUE-2, MUC, 1 
ftfttl MUR};-and In:dtisff'isl Pstk ~I -P7-districts, except for schools (18.130.0500)); and 
3. 25 percent for ~he M~<ed Yse Genffal Bttsiness Disffie~ (MU-CBD), Moe<ed Yse 
Gommereial1 (MUC-1) snd Ligh~ In:dm~risl snd Hea'\ry Indmff'ial ~I-L and I-H)-
districts, and for schools (18.130.0500)) in all districts. 
[Changes will be made by staff to all other relevant references in the Urban Forestry Manual to 
specify the R-12 district is in Tier 2.] 
Option 2: Keep the R -12 district in Tier 1. 
No Amendments Required 
City of Tigard Urban Forestry Code Re,·isions I Volume V I 83 
Issue l .B: Optio~1s for the Per Lot Minimum E ffective Tree Canopy Requirement 
Option 1: Eliminate the 15% per lot minimum for Tier 2 and 3 districts only (staff 
recommended option). 
Land Use Amendments: (Section 18.790.030.8 (Urban Fore.rtry Plan RequirementJ)) 
B. T ree Canopy Fee. If the supplemental arborist report demonstrates that the 
applicable standard percent effective tree canopy cover in Section 10, part 3, item N will not be 
provided through any combination o f tree planting or preserva tion for the overall development site 
(excluding streets) or that the 20 percent effective tree canopy cover will not be provided through 
any combination o f tree planting or preserva tion for any individual lo t or tract in the R-1 R-2 R-3.5 
R-4.5 R-7 and R-12 districts (when the overall development site meets or exceeds the standard 
percent effective tree canopy cover), then the applicant shall provide the city a tree canopy fee 
according to the methodology outlined in Section 10, part 4 o f the Urban Forestry Manual. ... 
[Changes will be made by staff to all o ther relevant references in the code and commentary for 
Chapter 18.790 to specify that the per lo t minimum is applicable to the R-1, R-2, R-3.5, R4.5, R-7, 
and R-12 districts only. If the R-12 district is moved into Tier 2 (33%), then the per lo t minimum 
will not apply to the R-12 district. If the per lo t minimum is reduced to 15%, then the text will 
reflect the change.) 
Non Land Use Amendments: (Urban "t<ore.rtry Manual Section 10, Part 3 (Urban Fore.rtry Plan-
Supplemental Arbori.rt Report Requirement.!)) 
M. A summary in table or o ther such organized format clearly demonstrating the effective tree 
canopy cover that will be provided for the overall development site (excluding streets) and 
for each lo t or tract in the R-1 R-2 R-3.5 R-4.5 R-7 and R-12 districts (excluding streets) 
as follows: .. . 
[Changes will be made by staff to all o ther relevant references in the Urban Fores try Manual to 
specify that the per lo t minimum is applicable to the R-1, R-2, R-3.5, R4.5, R-7, and R-12 districts 
only. If the R-12 district is moved into Tier 2 (33%), then the per lo t minimum will not apply to the 
R-12 district.) 
Cit:r of Tigard Urban l.'orcstry Code Rc,·isions I \ 'olumc \ ' I 84 
Option 2: Eliminate the 15% per lot minimum for all districts. 
Land Use Amendments: 
B. Tree Canopy Fee. If the supplemental arborist report demonstrates that the 
applicable standard percent effective tree canopy cover in Section 10, part 3, item N will not be 
provided through any combination of tree planting or preservation for the overall development site 
(excluding streets) or that the 20 percent effective tree canopy cover v.':ill not be provided through 
any combination of tree planting or preseNation fOf any individual lot or tract (when the overall 
development site meets ot· exceeds the standard percent effective tree canopy cover), then the 
applicant shall provide the city a tree canopy fee according to the methodology outlined in Section 
10, part 4 of the Urban Forestry Manual. 
[Changes will be made by staff to remove all references in the code and commentary to the per lo t 
minimum for Chapter 18. 790.) 
Non Land Use Amendments: (Urban ForeJtry Manual Sedion 10, Part 3 (Urban roreJtry Plan-
Supplemental ArboriJt Report RequirementJ)) 
M. A summary in table or o ther such organized format clearly demonstrating the effective tree 
canopy cover that will be provided for the overall development site (excluding su·eets) anti 
each lot or tract (excltldffi:f!' streets) as follows: 
[Changes will be made by staff to rem ove all references in the Urban Forestry Manual to the per lot 
minimum.] 
Option 3: K eep the 15% per lot minimum for all districts. 
No Amendments Required 
Cit)' of Tigard Urban Forestry Code Re,-isions I Volume V I 85 
Issue l.C: O ptions for Addressing Urban Forestry Plan Requirements for Residential Zones 
Option 1: Continue to require urban forestry plans for all residential districts (s taff 
recommended option). 
No Amendments Required 
Option 2: D o not require urban forestry plans for residential districts that allow small lo ts 
0ess than 5,000 sq. ft. lo t size allowed) which are the R-12 and R-25 districts. 
Land Use Amendments: (Section 18.790.020 (Applicabili!Y)) 
18.790.020 Definitions Applicability 
The requirements of this chapter apply to the following situations: 
A. The following land use reviews: 
1. Conditional Use (Type III); 
2. D owntown D esign Review (Type II and II I); 
3. Minor Land Partition (Type II) except in the R-12 and R-25 dis tricts: 
4. Planned D evelopment (Type III) except in the R-12 and R-25 dis tricts: 
5. Sensitive Linds Review (Type II and III); 
6. Site D evelopment Review (Type II); and 
7. Subdivision (Type II and III) except in the R-12 and R-25 districts. 
(Changes will be made by staff to all relevant references in the commentary for Chapter 18.790 to 
explain that the urban forestry plan requirements are not applicable to residential development in the 
R-12 and R-25 districts.] 
City of Tigard Urban l'orc, try Code Rc,·i,ion' I \ 'olumc \ ' I H6 
Issue l.D: Options for Addressing Urban Forestry Plan Requirements for Minor Land 
Partitions 
Option 1: Continue to require urban forestry plans for Minor Land Partitions (s taff 
recommended option). 
No Amendments Required 
Option 2: D o not require urban forestry plans for Minor Land Partitions. 
Land U se Amendments: (Section 18.790.020 (Applicabili!J)) 
18.790.020 Defiaitioas Applicability 
The requirements of this chapter apply to the following situations: 
A. The following land use reviews: 
1. Conditional Use (Type III); 
2. D owntown D esign Review (Type II and III); 
3. Minor Land Partition (Type II);. 
43. Planned D evelopment (Type III); 
.§.4. Sensitive Lands Review (Type II and III); 
65. Site D evelopment Review (Type II); and 
-:t6. Subdivision (Type II and III). 
[Changes will be made by staff to all relevant references in the commentary for Chapter 18.790 to 
explain that the urban forestry plan requirements are not applicable to Minor Land Partitions.] 
City of Tigard Urban l'orcstry Code Rc,·isions I Volume V I 87 
Issue l.E: Options for D eveloping Urban Forestry Plan 
Option 1: Allow landscape architects, in addition to arborists, to develop urban forestry 
plans (s taff recommended option). 
Land Use Amendments: (Chapter 18.115 (Li.rt qfTerm.~)J 
Landscape Architect 
[Adds the term "Landscape Architect" to chapter 18.115, no further changes to chapter 
required.] 
(Section 18.120.030 .. /l (Meaning if Spetijit Word.r and Tenm)) 
104. Landscape Architect" - An individual registered with the Oregon State Landscape Architect 
Board as a regis tered landscape architect. 
[Changes will be made by staff to all other relevant references in the code and commentary for 
Chapter 18.120 to add the term "landscape architect" where the term "arborist", " certified arborist" 
or "project arborist" is used.] 
(Section 18.745.040 .. /1.6 (Street TreeJ)) 
6. An existing tree may be used to meet the street tree standards provided that: 
a. The largest percentage of the tree trunk immediately above the trunk flare or root 
buttresses is either within the subject site or within the right of way immediately adjacent 
to the subj ect site; 
b . The tree would be permitted as a street tree according to the standards in Sections 2 and 
12 of the Urban Forestry Manual if it were newly planted; and 
c. The tree is shown as preserved in the Tree Preservation and Removal site plan (per 
18. 790.030.A.2), Tree Canopy Cover site plan (per 18. 790.030.A.3) and Supplemental 
)'rfbot"ist Report (per 18.790.030.1\.4) of a concurrent urban fores try plan and is eligible 
for credit towards the effective tree canopy cover of the site. 
[No further changes to chapter required.] 
(Section 18.790.030 .. A (Urban l'ore.rtry Plan RequirementJ) 
A. Urban Forestry Plan Requirements. An urban fores try plan shall: 
1. Be coordinated and approved by a landscape architect (the project landscape 
architect) or a person possessing dual certifications as a certified arborist and certified tree risk 
assessor (the project arborist); 
2. Meet the tree preserva tion and removal site plan standards in Section 10, part 
1 o f the Urban Fores try Manual; 
3. Meet the tree canopy site plan standards in Section 10, part 2 of the Urban 
Forestry Manual; and 
4. Meet the supplemental arbot"ist report standards in Section 10, part 3 o f the 
Cit\· o( Tigard Urban Fore> try Code RcYisiom I \ 'o lumc \ ' I 88 
Urban Forestry Manual. 
[Changes will be made by staff to all o ther relevant references in the code and commentary for 
Chapter 18.790 to add the term "landscape architect" where the term "arborist", "certified arborist" 
or "project arborist" is used, in addition changes will be made by staff to all o ther relevant 
references in the code and commentary for Chapter 18.790 to remove the word "arborist" where the 
term "supplemental arborist report" is used.] 
Non Land Use Amendments: (Urban 1:-'ore.rtry Manual Sedion 10, Part 1 (Urban P'ore.rtry Plan-
Tree Pre.rervation and Removal Site Plan Requirement.r)) 
N. A ny supplemental tree preserva tion specifications consistent with tree care industry 
standards that the project arborist o r landscape architect has determined are necessary for the 
continued viability of trees identified for preservation. 
[Changes will be made by staff to all o ther relevant references in the urban forestry manual to add 
the term " landscape architect" where the term "arborist", " certified arborist" or "project arborist" is 
used, in addition changes will be made by staff to all o ther relevant references in the urban fores try 
manual to rem ove the word "arborist" where the term "supplemental arborist report" is used.] 
Option 2: Co ntinue to allow o nly arbo rists to d evelo p urban forestry plan s. 
No Amendments Required 
City of Tigard Urban Forestry Code Rc,-isions I Volume\' I 89 
Issue 3.A: Opti~ns for the Tree Canopy Fee In Lieu 
Option 1: Continue to use the tree canopy fee in lieu methodology that captures the full 
value o f tree canopy (staff recommended option). 
No Amendments Required 
Option 2: Revise the tree canopy fee in lieu methodology to capture one-half the value o f 
tree canopy. 
Non Land Use Amendments: (Urban f-'oreJtry Manual Section 10, Part 5 ( f ree Canopy Fee 
Calculation Requirement.!)) 
A. T he tree canopy fee shall be calculated as follows: 
1. If the percentage o f effective tree canopy cover is less than the applicable standard 
percentage in part 3, item n above for the overall development site find the difference 
(in square feet) between the proposed effective tree canopy cover and the applicable 
standard effective tree canopy cover for the overall development site and multiply the 
difference (in square feet) by: 
a. One-half ~the most recent wholesale m edian tree cos t es tablished by the PNW-
ISA for a 3 inch diameter deciduous tree in the Willamette Valley, OR divided by 
59 square feet. 
2. In cases where the overall development site meets the standard percentage in part 3.N 
above yet the percentage o f effective tree canopy cover is less than 20 percent for any 
individual lo t or tract, find the difference (in square feet) between the proposed 
effective tree canopy cover and 20 percent effective tree canopy cover for each deficient 
lo t or tract and multiply the difference (in square feet) by: 
a. One-half ~the mos t recent wholesale m edian tree cost es tablished by the PNW-
ISA for a 3 inch diameter deciduous tree in the Willamette Valley, OR divided by 
59 square feet. 
[Changes will be made by staff to all relevant references in the commentary for Chapter 18.790 to 
explain why the tree canopy fee in lieu in the Urban Forestry Manual is one-half the value o f tree 
canopy.] 
City of Tigard Urban l:ore>try Code Rc,·i>ion> I \'olumc \ ' I 911 
Additional Amendments from the April16, 2012 Planning Commission Meeting 
Additional Amendments 1: Minor text amendment to the summary heading of 
section 18.790.030.A. 
Land Use Amendments: (Section 18.790.030.A (Urban Forestry Plan Requirement.~) 
A. Urban Forestry Plan Submittal Requirements. An urban forestry plan shall: 
[No further changes.] 
City of Tigard Urban Fore~ try Code Rc,·isions I Volume V I 91 
Additional Amendments 2: Reduce the per lot effective tree canopy cover 
requirement to 15% in Chapter 18.790 and the Urban Forestry Manual. 
Land Use Amendments: (Sedion 18.790.030.B (Urban i'ore.rtry Plan RequirementJ)) 
B. Tree Canopy Fee. If the supplemental arborist report demonstrates that the 
applicable standard percent effective tree canopy cover in Section 10, part 3, item N . will not 
be provided through any combination of tree planting or preservation for the overall 
development site (excluding streets), or that the ~ 1.5 percent effective tree canopy cover 
will not be provided through any combination o f tree planting or preservation for any 
individual lo t or tract (when the overall development site meets or exceeds the standard 
percent effective tree canopy cover), then the applicant shall provide the city a tree canopy 
fee according to the methodology outlined in Section 10, part 4 o f the Urban Forestry 
Manual. 
[No further changes.] 
(Section 18. 790.050.D.5 (l:::lexible Incentive.r and Standard.rfor the 
Pre.rervation rif Signijicant Tree GroveJ)) 
1. Adjustment to Minimum E ffective Canopy Requirement. The 
requirement for~ 1.5 percent effective tree canopy cover per lo t is not required 
when: 
[No further changes.] 
(Sedion 18.790.050.D.5, Commentary) 
The fifth flexible and incentive based standard is an adjustment to the minimum effective 
canopy requirement. A standard Urban Forestry Plan requires ~ 1.5 percent effective tree 
canopy per lot in addition to the overall development site effective canopy requirement 
which is based on zoning (25, 33 or 40 percent). 
[No further changes.] 
Non Land Use Amendments: (Urban f'om'try Manual Sedion 10, Part 3.0 (Urban l:::are.rtry 
Plan - Supplementai Arbori.rt Report RequirementJ)) 
0 . If the percent o f effective tree canopy cover is less than the applicable standard 
percent in item n above for the overall development or less than~ 1.5 percent for any lot or 
tract (when the overall development site meets or exceeds the standard percent effective tree 
canopy cover in item n), calculate the tree canopy fee required to mee t the applicable 
standard percent effective tree canopy cover in item n above for the overall development site 
or~ 1.5 percent effective tree canopy cover for each lot or tract (only if the overall 
development site meets or exceeds the standard percent effective tree canopy cover in item n 
but individual lo ts or tracts do provide ~ 1.5 percent effective tree canopy cover) according 
to the methodology in Section 10, part 4 o f the Urban Foresu·y Manual. 
(Urban Fore.rtry Manual S ection 10, Part 4.A .2 (Urban f'o re.rtry 
Plan - Tree Canopy Fee Calculation Requirement:1)) 
2. In cases where the overall development site meets the standard percentage in 
part 3.N above yet the percentage of effective tree canopy cover is less than~ 
CitY of Tigard Urban l:orcstry Code Rc,·isions I \ 'olumc \' I '>2 
15. percent for any individual lot or tract, find the difference (in square feet) 
between the proposed effective tree canopy cover and ~ 15. percent effective 
tree canopy cover for each deficient lot or tract and multiply the difference (in 
square feet) by: 
[No further changes.] 
Additional Amendments 3: Correct scrivener's errors in section 18.790.030.C. 
Land Use Amendments: (18.790.030.C (Urban Forestry Plan Requirements)) 
&.C Tree Canopy Fee Use. Tree canopy fees provided to the city shall 
[No further changes.] 
Additional Amendments 4: Correct scrivener's errors in ESEE and correct 
boundaries of significant tree groves #38 and #62. 
Land Use Amendments: (note: the full text from the ESEE ana!Jsis aJJociated with these t:orreded 
J(rivener's errors is not provided) 
Change "18. 70" to "18. 790" 
Change "18. 770" to "18. 790" 
Change "18. 7 50" to "18. 790" 
Change "18. 7 55" to "18. 77 5" 
(see UFCR Volume III, page 22) 
(see UFCR Volume III, pages 33 and 83) 
(see UFCR Volume III, page 4 7) 
(see UFCR Volume III, pages 34 (4 times), 47 and 64) 
Land Use Amendments: Adjust boundaries of inventoried Tree Groves #38 and #62 on 
the Significant Tree Grove Map (note: the amended Significant Tree Grove Map is on page 
76 of the packet and provided with the staff report for the April 16, 2012 Planning 
Commission meeting). 
City of Tigard Urban Forestry Code Rc,·isions I Volume V I 93 
Additional Amendments 5: Minor text amendment to clarify the review and approval 
_Qrocess in sections 18.790.070.B.1-3. 
Land Use Amendments: (18.790.070.8.1 (Exemptiom [from the Type I Modijimtion to the Urban 
F'oreJtry Plan Component ~fan Approved Land U.re Permit])) 
b. A revised tree canopy site plan and supplemental arborist report 
are submitted for review and approval prior to removal for review and approval that reflect 
the proposed changes to the previously approved Urban Forestry Plan~ ftfld. The revised tree 
canopy site plan and supplemental arborist report shall demonstrate how either the effective 
tree canopy cover requirements in Section 10, part 3 of the Urban Forestry Manual will be 
provided by the pmposed combination of tree planting, ftfld. preserva tion; and/ or,- payment 
o f a tree canopy fee in lieu of planting or presen ration. will be provided to make up the 
difference between the proposed effective tree canopy cover and the effective tree canopy 
cover requirements in Section 10, part 3, of the Urban Forestry Manual for the lot or tract 
where the modification is proposed. 
[No further changes.] 
(18.790.070.8.2) 
c. A revised tree canopy site plan and supplemental arborist report 
are submitted for review and approval prior to planting for review and aooroval that reflect 
the proposed changes to the previously approved Urban Forestry Plan. 
[No further changes.] 
(18.790.070.8. 3) 
b. A revised tree preserva tion and removal site plan, tree canopy 
site plan and supplem ental arborist report are submitted for review and approval prior to 
modification of the tree pro tection fencing for review an:d approval that reflect the proposed 
modifications to the previously approved Urban Forestry Plan. 
[No further changes.] 
City of TiganJ Urban l:o rc>try C:oJc Rc,·i>iom I \ 'o lumc \ ' I '!4 
Additional Amendments 6: Grant 1.25x bonus credit for planting native trees. 
Non Land Use Amendments: (Section 10, Part 3.M.2 (Urban Forestry Plan- Supplemental 
Arborist Report RequirementJ)) 
c. The mature canopy area (in square feet) of all open grown trees in the tree canopy 
site plan, except for those from the native tree list in the Urban Forestcy Manual, 
to be planted and maintained within the overall development site and each lot or 
tract (or associated right of way, excluding median trees). 
d. 1.25 times the mature canopy area (in square feet) of all open grown trees from 
site plan to be . h tree canopy 
Manualm t e h lot or tract . . in the Urban Forestry elo ment site and eac the nauye tree ~st . within the overall dey P d d mamtamed plante an 
(or associated right of way excluding median trees). 
e. 1.25 times :fthe mature canopy area (in square feet) of each stand in the tree 
canopy site plan to be planted and maintained within the overall development site 
and each lot or tract (or associated right of way, excluding median trees). The 
eligible mature tree canopy area shall be the portion directly above the overall 
development site and each lot or tract (or associated right of way). 
f. Divide the tree canopy area (calculated per part 3 .M.2.a-~ above) for the overall 
development site and each lot or tract by the total area of the overall development 
site and each lot or tract respectively to determine the effective tree canopy cover 
for the overall development site and each lot or tract. 
[No further changes.] 
(note: above lettering is revised due to the insertion of item d) 
(note: for consistency the Example Supplemental Report Template in 
Appendix 9 of the Urban Forestry Manual is recommended for amendment 
as shown on page 77 of the April 16, 2012 Planning Commission Packet) 
City of Tigard Urban Forestry Code Rc,·isions I Volume V I 95 
Additional Amendments 7: Minor text amendment to remove a repetitive approval 
criterion for tree removal_I>~~lllit requirements in sensitive lands. 
Non Land Use Amendments: (Section 6, Part 1.B.6 (Semitive LandJ Tree Removal Standard!)) 
6:- "The tree i ~ l i~ ted o n th e nni~~ nee tree li ~ t . 
[No further changes.] 
(note: numbering of the section is revised and the cross reference to the 
N uisance Tree List in the sidebar is struck due to the deletion o f item 6) 
(Section 6, Part 1. C (Semitive Landr Tree Removal Standard!)) 
C. Unless removed for thinning purposes (part 1.B.H .10. above) the city manager or 
designee shall condition the removal of each tree in sensitive lands upon the 
planting of a replacement tree in accordance with the Sensitive Lands Tree 
Replacement Standards in Section 6, part 2 of the Urban Forestry Manual. 
[No further changes.] 
C:iry of Tigard Urban l'orc<Ln· Code Rc,·i<ions I \'olumc \ ' I % 
<
 
0 c il < 

To: 
From: 
Re: 
Date: 
City of Tigard 
Memorandum 
City Council, Planning Commission, Members of the Public 
Todd Prager, Asso<;iate Planner/ Arborist 
Log of Input on the Draft Urban Forestry Code Revisions 
December 13, 2011 
The Urban Forestry Code Revisions Citizen Advisory Committee advised staff throughout the 
development of the draft code to ensure its consistency with community goals and policies. Staff 
logged updates to the draft Urban Forestry Code Revisions for the citizen advisory committee 
throughout the process to allow them to track changes between drafts. 
The last meeting of the citizen advisory committee was September 14, 2011, in which they finalized 
their set of guiding principles for each topic area of the draft code. The guiding principles represent 
the consensus view of the citizen advisory committee and serve staff during the technical and public 
review phase to ensure any code edits remain consistent with their consensus view. 
As part of the technical and public review phase of the project (September 14, 2011 to December 
12, 2011), staff kept a log of input from the technical advisory committee and public, and staffs 
response to that input. This allows for tracking of additional changes to the draft Urban Forestry 
Code Revisions for evaluation of consistency with the citizen advisory committee's guiding 
principles. It also provides decision-makers understanding of how community input is being 
addressed by staff through the draft code. 
City of Tigard Urban Forestry Code Re,-isions I Volume V I 99 

Technical Advisory Committee Input 
# COMMENTER SUMMARIZED COMMENT STAFF U PDATE/RESPONSE CODE 
(DATE) SECTION 
1. Todd Prager Remove reference to numerical This has been incorporated into the draft Urban 
(9-15-2011) risk rating in the Tree Risk Urban Forestry Manual. The code required Forestry 
Assessment Form under threshold for abatement is tiered based on the Manual 
"Recommended Hazard Tree size of the tree or tree part, and is not simply Appendix 1 
Abatement Procedures" line. "9" (see definition of hazard tree in chapter 
8.02). The code, and not the Tree Risk 
Assessment Form, will be used as the reference 
to determine when abatement is required 
2. Todd Prager Revise commentary for 18.790.030 This has been incorporated into the 18.790.030 
(9-15-2011) (Urban Forestry Plan) for commentary for the draft Urban Forestry Code Commentary 
consistency with code provisions. Revisions. Urban forestry plans require trees 
over 6-inch diameter and those trees less than 
6-inch diameter that are pro tected by the 
provisions of Title 8 (e.g. street trees, heritage 
trees, etc .) to be inventoried prior to 
development. The commentary for 18.790.030 
has been revised to clarify the inventory 
requirements for trees less than 6-inch 
diameter. 
3. Todd Prager As recommended by a Citizen This has been incorporated into the draft 18.790.060 
(9-16-2011) Advisory Committee member, use Urban Forestry Code Revisions and Code & 
the term "in effect" rather than commentary. The term "in effect" replaces the Commentary 
"active" in section 18.790.060 to term "active" to describe the validity period of 
describe the validity period for an an urban forestry plan in section 18.790.060 
urban forestry plan since the term 
"in effect" is more commonly used 
in the development code when 
describing validity periods. 
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U r b a n  F o r e s t r y  M a n u a l  i s  p a r t  o f  
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S T A F F  U P D A T E / R E S P O N S E  C O D E  
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t e r m  " p r e l i m i n a r y  d r a f t "  h a v e  b e e n  r e m o v e d  M a n u a l  
f r o m  t h e  U r b a n  F o r e s t r y  M a n u a l .  
# COMMEN TER SUMMARIZED COMMEN T STAFF U PDATE/RESPONSE CODE 
(DATE) SECTION 
7. Todd Prager In chapter 8.06, provide a cross This has been incorporated into the draft 8.06.020 
(9-19-2011) reference to chapter 2.04 which Urban Forestry Code Revisions. Previously, 8.02.020 
establishes the authority to adopt the process for adopting and amending Code 
and amend administrative rules. administrative rules in the Urban Forestry 
Manual was outlined in chapter 8.06. However, 
council recently adopted a process for adopting 
and amending administrative rules in chapter 
2.04. Administrative rulemaking procedures 
are housed within one chapter of the code to 
allow cross referencing when various chapters 
include administrative rules. This makes the 
process for administrative rulemaking more 
consistent than if each chapter had a separate 
process. 
8. Todd Prager Re-letter and re-number within the This has been incorporated into the dra ft Urban 
(10-7-2011) Urban Forestry Manual sections so Urban Forestry Manual. Re-lettered and re- Forestry 
the hierarchy is more consistent numbered within the Urban Forestry Manual Manual 
with the Tigard Municipal Code sections so the hierarchy is more consistent 
style guide. E nsure any cross with the Tigard Municipal Code style guide. 
references in the manual are E nsured any cross references in the manual are 
correspondingly changed in the correspondingly changed in the code. 
code. 
9. Tom McG uire Shorten section 18.745.040.A.6 for This has been incorporated into the draft 18.745.040 
(10-11 -2011) readability by citing the Urban Urban Forestry Code Revisions. Revised 
Forestry Manual standards only section 18.745.040.A.6 accordingly by citing the 
once. Urban Forestry Manual standards only once. 
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I f  t h e r e  i s  a  c o n c u r r e n t  T y p e  I I I  
P l a n n i n g  C o m m i s s i o n  r e v i e w  
( T y p e  I l i A ) ,  a l l o w  t h e  r e v i e w  b o d y  
t o  b e  P l a n n i n g  C o m m i s s i o n  f o r  
e f f i c i e n c y  p u r p o s e s .  O t h e r w i s e ,  
r e q u i r e  t h e  r e v i e w  b o d y  t o  b e  t h e  
h e a r i n g s  o f f i c e r  ( T y p e  I I I B )  f o r  
d i s c r e t i o n a r y  u r b a n  f o r e s t r y  p l a n  
r e v 1e w s .  
I n  t h e  n a t i v e  t r e e  l i s t ,  c h a n g e  
" G a r r y  O a k "  t o  " O r e g o n  W h i t e  
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c o m m o n  n a m e  o f  t h e  t r e e  u s e d  i n  
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b o d y  ( P l a n n i n g  C o m m i s s i o n  o r  h e a r i n g s  
C o m m e n t a r y  
o f f i c e r )  w i l l  d e p e n d  o n  w h e t h e r  t h e r e  i s  a  
c o n c u r r e n t  T y p e  I I I  r e v i e w .  F o r  e x a m p l e ,  i f  a n  
a p p l i c a n t  f o r  a  P l a n n e d  D e v e l o p m e n t  ( T y p e  I I I  
P l a n n i n g  C o m m i s s i o n  r e v i e w )  c h o o s e s  t o  
r e c e i v e  a  d i s c r e t i o n a r y  u r b a n  f o r e s t r y  p l a n  
r e v i e w ,  t h e  r e v i e w  b o d y  w i l l  b e  t h e  P l a n n i n g  
C o m m i s s i o n .  H o w e v e r ,  i f  a n  a p p l i c a n t  f o r  a  
C o n d i t i o n a l  U s e  P e r m i t  ( T y p e  I I I  h e a r i n g s  
o f f i c e r  r e v i e w )  c h o o s e s  t o  r e c e i v e  a  
d i s c r e t i o n a r y  u r b a n  f o r e s t r y  p l a n  r e v i e w ,  t h e  
r e v i e w  b o d y  w i l l  b e  t h e  h e a r i n g s  o f f i c e r .  
F i n a l l y ,  i f  a n  a p p l i c a n t  d o e s  n o t  h a v e  a  
c o n c u r r e n t  T y p e  I I I  r e v i e w  ( e . g .  S u b d i v i s i o n ,  
M i n o r  L a n d  P a r t i t i o n ,  e t c . ) ,  y e t  c h o o s e s  t o  
r e c e i v e  a  d i s c r e t i o n a r y  u r b a n  f o r e s t r y  p l a n  
r e v i e w ,  t h e  r e v i e w  b o d y  w i l l  b e  t h e  h e a r i n g s  
o f f i c e r .  
T h i s  h a s  b e e n  i n c o r p o r a t e d  i n t o  t h e  d r a f t  U r b a n  
.  
U r b a n  F o r e s t r y  M a n u a l .  R e v i s e d  t h e  n a t i v e  t r e e  
F o r e s t r y  
l i s t  i n  t h e  U r b a n  F o r e s t r y  M a n u a l  a c c o r d i n g l y  M a n u a l  
b y  c h a n g i n g  " G a r r y  O a k "  t o  " O r e g o n  W h i t e  A p p e n d L' I :  5  
O a k "  f o r  c o n s i s t e n c y  w i t h  t h e  c o m m o n  n a m e  
o f  t h e  t r e e  u s e d  i n  t h e  o t h e r  t r e e  l i s t s .  
T h i s  h a s  b e e n  i n c o r p o r a t e d  i n t o  t h e  d r a f t  U r b a n  
U r b a n  F o r e s t r y  M a n u a l .  R e v i s e d  t h e  e x a m p l e  
F o r e s t r y  
d r a w i n g s  s o  t h a t  t h e  5 0 - f o o t  s t r e a m  b u f f e r  i s  
M a n u a l  
t a k e n  f r o m  t h e  e x i s t i n g  w e t l a n d  e d g e .  A p p e n d i c e s  
7 , 8 ,  1 0 , a n d  
1 3  
# COMMEN TER SUMMARIZED COMMEN T STAFF U PDATE/RESPONSE CODE 
(DATE) SECTION 
13. Damon Reische, CWS Coordinate on drawings and No revisions were made based on dus Urban 
(10-18-2011) specifications in the Urban comment. Todd Prager and Damon Reische Forestry 
Forestry Manual to ensure they do met on 10-21-2011 to coordinate on the Manual 
not conflict with CWS LIDA drawings and specifications for both 
Handbook. documents . o conflicts were identified due to 
the fact that both documents contain examples 
that can be modified on a project specific basis. 
There is enough flexibility in design to allow 
trees to be planted within the CWS example 
LIDA facilities. 
14. Brian Rager Do not label drawings as Tills has been incorporated into the draft Urban 
Susan Hartnett "standard" drawings since the city Urban Forestry Manual. Revised the first word Forestry 
(10-18-2011) will allow equivalent alternatives to from "standard" to "example" in the names of Manual 
meet covered soil volume appendices 14 and 17. Revised names Sections 12 
requirements. Consider calling accordingly in Sections 12 and 13 of the Urban and 13 
them "example" drawings that Forestry Manual. Appendices 
applicants could use unless they 14 and 17 
propose an equivalent alternative. 
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c a n o p y  s t a n d a r d s  s o  t h a t  a  b u f f e r  
a t  t h e  p e r i m e t e r  o f  a  p a r k i n g  l o t  i s  
i n c l u d e d  i n  t h e  c a l c u l a t i o n  o f  
p a r k i n g  a r e a  a n d  c a n o p y  c o v e r .  I f  
t h e r e  a r e  e x i s t i n g  m a t u r e  t r e e s  n e a r  
t h e  p a r k i n g  p e r i m e t e r ,  t h e r e  c o u l d  
b e  a n  i n c e n t i v e  t o  p a v e  t o  c a p t u r e  
t h e  c a n o p y  o f  t h e  m a t u r e  t r e e s .  B y  
a d d i n g  a  b u f f e r  a t  t h e  p e r i m e t e r ,  
t h e  i n c e n t i v e  t o  p a v e  a d d i t i o n a l  
a r e a  c o u l d  b e  r e d u c e d .  
T h e  d r a w i n g s ,  s p e c i f i c a t i o n s ,  a n d  
a t t a c h m e n t s  i n  t h e  U r b a n  F o r e s t r y  
M a n u a l  s h o u l d  b e  c a l l e d  
" a p p e n d i c e s " .  
S T A F F  U P D A T E / R E S P O N S E  
C O D E  
S E C T I O N  
N o  r e v i s i o n s  w e r e  m a d e  b a s e d  o n  t h i s  
1 8 . 7 4 5 . 0 5 0  
c o m m e n t .  S t a f f  s t u d i e d  t h i s  i s s u e  i n  m o r e  d e t a i l  
U r b a n  
a n d  d i s c u s s e d  o p t i o n s  w i t h  t h e  c o n s u l t a n t .  T h e  
F o r e s t t y  
i s s u e  w i t h  c r e a t i n g  a  s t a n d a r d  b u f f e r  a r o u n d  t h e  
M a n u a l  
p a r k i n g  a r e a  i s  t h a t  i t  m a k e s  t h e  p a r k i n g  l o t  
S e c t i o n  1 3  
c a n o p y  s t a n d a r d s  m o r e  d i f f i c u l t  t o  a c h i e v e  i n  
s i t u a t i o n s  w h e r e  t h e r e  a r e  n o  e x i s t i n g  m a t u r e  
t r e e s .  T h i s  i s  b e c a u s e  t h e  b u f f e r  w o u l d  a d d  t o  
t h e  p a r k i n g  a r e a  a n d  r e q u i r e d  a d d i t i o n a l  c a n o p y  
t o  c o v e r  i t .  A f t e r  a p p l y i n g  t h e  p a r k i n g  l o t  
c a n o p y  s t a n d a r d s  t o  t h e  p e e r  r e v i e w  p r o j e c t  
s i t e s ,  s t a f f  a n d  t h e  c o n s u l t a n t  a r e  c o n f i d e n t  t h a t  
t h e  c a n o p y  s t a n d a r d s  a r e  r e a d i l y  a c h i e v a b l e  
a c r o s s  a  r a n g e  o f  d e v e l o p m e n t  s c e n a r i o s  .  . A  
s c e n a r i o  w h e r e  a n  a p p l i c a n t  w o u l d  p a v e  
a d d i t i o n a l  a r e a  t o  c a p t u r e  t h e  d r i p l i n e  o f  a  
m a t u r e  t r e e  r e p r e s e n t s  a n  o u t l y i n g  e x c e p t i o n .  
H o w e v e r ,  i n  o r d e r  t o  a d d r e s s  t h e s e  t y p e s  o f  
o u t l y i n g  e x c e p t i o n s ,  t h e  d r a f t  c o d e  a l l o w s  t h e  
d i r e c t o r  t o  a p p r o v e  a n  e q u i v a l e n t  a l t e r n a t i v e  
p a r k i n g  l o t  c a n o p y  p r o p o s a l  b y  a  l a n d s c a p e  
a r c h i t e c t .  
'  
T h i s  h a s  b e e n  i n c o r p o r a t e d  i n t o  t h e  d r a f t  U r b a n  
U r b a n  F o r e s t r y  M a n u a l .  T h e  d r a w i n g s ,  F o r e s t r y  
s p e c i f i c a t i o n s ,  a n d  a t t a c h m e n t s  i n  t h e  U r b a n  M a n u a l  
F o r e s t ! ) '  M a n u a l  a r e  n o w  c a l l e d  " a p p e n d i c e s "  A p p e n d i c e s  
a n d  h a v e  e a c h  b e e n  a s s i g n e d  a n  a p p e n d i x  
n u m b e r .  
# COMMEN TER SUMMARIZED COMMEN T STAFF UPDATE/RESPONSE CODE 
(DATE) SECTION 
17. Todd Prager For scaled drawings, indicate the This has been incorporated into the draft Urban 
(10-19-2011) sheet size so people know how Urban Forestry Manual. Indicated sheet size for Forestry 
large to print the sheet for the all scaled drawings. Manual 
correct scale. Appendices 
7, 8, 10, 12, 
13, and 16 
18. Todd Prager D o not specify a compaction This has been incorporated into the draft Urban 
(10-19-2011) density in the covered soil volume Urban Forestry Manual. Revised first sentence Forestry 
specifications. This will allow of Part 4.D of the covered soil volume Manual 
flexibility to meet the compaction specifications as follows " ... compact each lift to Appendix 14 
requirements for specific !tt le~tst 85 the required percent o f maximum 
applications. density." 
19. D amon Reische, CWS E nsure that thinning standards in N o revisions were made based on this Urban 
(10-21-201 1) the Urban Forestry Manual do no t comment. The thinning standards require a Forestry 
conflict with CWS standards. certified arborist or certified fores ter approval Manual 
that the thinning of interior trees within a stand Section 3, 5, 
of trees is necessary for overall stand health, the 6, 7, 8, and 9 
thinning will result in no less than 80% canopy 
cover at maturity for the area to be thinned, 
and that thinning of non-native trees is 
maximized prior to the thinning of native trees. 
In addition, CWS will be required to issue a 
service provider letter before final approval. 
The combination of a thinning 
recommendation by a certified professional and 
final approval by CWS will minimize future 
conflicts. 
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( 1 1 - 3 - 2 0 1 1 )  
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( 1 1 - 1 7 - 2 0 1 1 )  
S U M M A R I Z E D  C O M M E N T  
I n  c h a p t e r  1 8 . 1 1 5  ( L i s t  o f  T e r m s ) ,  
d e l e t e  t e r m s  t h a t  h a v e  b e e n  d e l e t e d  
f r o m  c h a p t e r  1 8 . 7 9 0 .  
C o r r e c t  s p e l l i n g ,  g r a m m a r ,  a n d  
p u n c t u a t i o n ,  a n d  c o n f o r m  t o  A P  
s t a n d a r d s  t h r o u g h o u t  t h e  c o d e  a n d  
c o n u n e n t a r y .  
W h e n  d e t e r m i n i n g  t h e  r e g u i r e d  
n u m b e r  o f  s t r e e t  t r e e s  ( s t r e e t  
f r o n t a g e /  4 0 ) ,  c l a r i f y  t h e  r e g u i r e d  
n u m b e r  o f  s t r e e t  t r e e s  w h e n  t h e  
r e s u l t  i s  a  f r a c t i o n  
A d d  a  d i a g r a m  t o  v i s u a l l y  d e s c r i b e  
t h e  d e f i n i t i o n  o f  " c a l i p e r " .  
S T A F F  U P D A T E / R E S P O N S E  
C O D E  
S E C T I O N  
T h i s  h a s  b e e n  i n c o r p o r a t e d  i n t o  t h e  d r a f t  
1 8 . 1 1 5  
U r b a n  F o r e s t r y  C o d e  R e v i s i o n s .  D e l e t e d  
C o d e  
t e r m s :  
- C o m m e r c i a l  F o r e s t r y  
- P r u n i n g  
- R e m o v a l  
- S e n s i t i v e  L a n d s  ( c h a p t e r  1 8 . 7 9 0  s p e c i f i c  
d e f i n i t i o n )  
- T r e e  ( c h a p t e r  1 8 . 7 9 0  s p e c i f i c  d e f i n i t i o n )  
T h i s  h a s  b e e n  i n c o r p o r a t e d  i n t o  t h e  d r a f t  
T h r o u g h o u t  
U r b a n  F o r e s t r y  C o d e  R e v i s i o n s .  
C o d e &  
C o m m e n t a r y  
T h i s  h a s  b e e n  i n c o r p o r a t e d  i n t o  t h e  d r a f t  
1 8 . 7 4 5 . 0 4 0  
U r b a n  F o r e s t r y  C o d e  R e v i s i o n s .  C l a r i f i e d  t h a t  
C o d e  
w h e n  t h e  r e s u l t  i s  a  f r a c t i o n ,  t h e  m i n i m u m  
n u m b e r  o f  r e g u i r e d  s t r e e t  t r e e s  s h a l l  b e  
d e t e r m i n e d  b y  r o u n d i n g  t o  t h e  n e a r e s t  w h o l e  
n u m b e r  .  
T h i s  h a s  b e e n  i n c o r p o r a t e d  i n t o  t h e  d r a f t  8 . 0 2  
U r b a n  F o r e s t r y  C o d e  R e v i s i o n s .  A  d i a g r a m  o f  1 8 . 1 2 0  
c a l i p e r  f r o m  t h e  C i t y  o f  L a w r e n c e ,  K a n s a s  h a s  
C o d e  
b e e n  a d d e d  a n d  l a b e l e d  a s  f i g u r e  8 . 0 2 . 1  t o  T i t l e  
8  a n d  f i g u r e  1 8 . 1 2 0 . 3  t o  T i t l e  1 8 .  
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24. 
25. 
26. 
COMMENTER 
(DATE) 
Cheryl Caines 
Tom McGuire 
(11 -17-2011) 
Cheryl Caines 
Tom McGuire 
(11 -17-2011) 
Cheryl Caines 
Tom McGuire 
(11 -17-2011) 
SUMMARIZED COMMEN T 
Add a diagram to visually describe 
the definition of "diameter at 
breast height (DBH)". 
Revise the definition of "open soil 
volume" by removing the second 
sentence. There should not be a 
standard in a definition. 
Revise the submittal requirement 
in section 18.330.040.A.4 back to 
"a landscape plan" for consistency 
with the submittal requirements in 
other sections of the code. The 
elements to be included in a 
landscape plan will be clarified as 
part o f the upcoming regulatory 
improvement initiative. Clarifying 
landscape plan submittal 
requirements is out of scope for 
the urban forestry code revisions 
project. 
STAFF UPDATE/RESPONSE CODE 
SECTION 
This has been incorporated into the draft 8.02 
Urban Forestry Code Revisions. Diagrams 18.1 20 
from the City of Portland have been added for Code& 
the definition of DBH in Title 8 and Title 18. Commentary 
Figures 8.02.2 and 18.120.4 illustrate DBH for 
a single trunk tree, figures 8.02.3 and 18.120.5 
illustrate DBH for a tree with a split trunk 
above the ground, and figures 8.02.4 and 
18.1 20.6 illustrate DBH for a tree with multiple 
trunks at or below ground. Commentary has 
been added to Chapter 18.120 to explain the 
figures. 
This has been incorporated into the draft 8.02 
Urban Forestry Code Revisions. The standard 18.120 
has been removed from the defmition of open Code 
soil volume. 
This has been incorporated into the draft 18.330.040 
Urban Forestry Code Revisions. The elements Code & 
to be included in a landscape plan will be Commentary 
clarified as part of the upcoming regulatory 
improvement initiative. 
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( D A T E )  
C h e r y l  C a i n e s  
T o m  M c G u i r e  
( 1 1 - 1 7 - 2 0 1 1 )  
C h e r y l  C a i n e s  
T o m  M c G u i r e  
( 1 1 - 1 7 - 2 0 1 1 )  
C h e r y l  C a i n e s  
T o m  M c G u i r e  
( 1 1 - 1 7 - 2 0 1 1 )  
S U M M A R I Z E D  C O M M E N T  
R e m o v e  t h e  t e r m  " c o n c e p t "  a n d  
s p e c i f y  t h a t  t h e  u r b a n  f o r e s t r y  p l a n  
n e e d s  t o  m e e t  t h e  r e q u i r e m e n t s  o f  
c h a p t e r  1 8 . 7 9 0 .  
R e m o v e  t h e  w o r d  " s i g n i f i c a n t "  
f r o m  s e c t i o n  1 8 . 3 5 0 . 0 5 0 . A . 2  
b e c a u s e  t h e  w o r d  i s  u n d e f i n e d ,  a n d  
c o u l d  b e  m i s c o n s t r u e d  a s  a p p l y i n g  
o n l y  t o  " s i g n i f i c a n t  t r e e  g r o v e s " .  
T h e  i n t e n t  o f  t h e  a p p r o v a l  
c r i t e r i o n  i s  t o  c o n s i d e r  t h e  
p r e s e t v a t i o n  o f  a n y  t r e e  o r  n a t u r a l  
r e s o u r c e  a s  p a r t  o f  p l a n n e d  
d e v e l o p m e n t s .  
S p e c i f y  t h a t  t h e  d i r e c t o r  h a s  t h e  
a u t h o r i t y  t o  a p p r o v e  a l t e r n a t e  
g r a d i n g  c o n t o u r  i n t e t v a l s  f o r  a  
d e t a i l e d  d e v e l o p m e n t  p l a n  f o r  a  
p l a n n e d  d e v e l o p m e n t .  
S T A F F  U P D A T E / R E S P O N S E  
C O D E  
S E C T I O N  
T h i s  h a s  b e e n  i n c o r p o r a t e d  i n t o  t h e  d r a f t  
1 8 . 3 5 0 . 0 4 0  
U r b a n  F o r e s t r y  C o d e  R e v i s i o n s .  S i n c e  t h e  t e r m  
C o d e &  
" c o n c e p t "  i s  n o t  d e f i n e d ,  i t  i s  m o r e  e x p l i c i t  t o  
C o m m e n t a r y  
s i m p l y  r e q u i r e  a n  u r b a n  f o r e s t r y  p l a n  t h a t  m e e t s  
t h e  c o d e  r e q u i r e m e n t s .  P l a n n i n g  c o m m i s s i o n  
w o u l d  s t i l l  r e s e t v e  t h e  r i g h t  t o  r e q u i r e  
m o d i f i c a t i o n s  t o  t h e  u r b a n  f o r e s t r y  p l a n  d u r i n g  
t h e  d e t a i l e d  d e v e l o p m e n t  p l a n  a p p r o v a l  
p r o c e s s .  
T h i s  h a s  b e e n  i n c o r p o r a t e d  i n t o  t h e  d r a f t  
1 8 . 3 5 0 . 0 5 0  
U r b a n  F o r e s t r y  C o d e  R e v i s i o n s .  T h e  w o r d  
C o d e &  
" s i g n i f i c a n t "  h a s  b e e n  r e m o v e d ,  a n d  t h e  
C o m m e n t a r y  
r a t i o n a l e  f o r  r e m o v i n g  t h e  w o r d  h a s  b e e n  
i n c l u d e d  i n  t h e  c o m m e n t a r y  .  
T h i s  h a s  b e e n  i n c o r p o r a t e d  i n t o  t h e  d r a f t  1 8 . 3 5 0 . 0 6 0  
U r b a n  F o r e s t r y  C o d e  R e v i s i o n s .  T h e  d i r e c t o r  C o d e  
i s  s p e c i f i e d  a s  t h e  a u t h o r i t y  t o  a p p r o v e  a l t e r n a t e  
g r a d i n g  c o n t o u r  i n t e t v a l s .  
# COMMENTER SUMMARIZED COMMEN T STAFF U PDATE/RESPONSE CODE 
(DATE) SECTION 
30. Cheryl Caines D o not specify that the This has been incorporated into the draft 18.350.070 
Tom McGuire commission may require alternate Urban Forestry Code Revisions. T here are no Code& 
(11 -17-2011) urban forestry plans to ensure tree changes to the detailed development plan Commentary 
preservation. The existing approval criteria. 
language allows the commission to 
require alternate site plans, which 
encompasses grading plans, urban 
fores try plans, etc. Specifying that 
the commission may require 
alternate urban forestry plans is 
duplicative. 
31. Cheryl Caines In the site development review This has been incorporated into the draft 18.360.070 
Tom McG uire submittal requirem ents, include a Urban Forestry Code Revisions. Chapter Code & 
(11 -17-2011) cross reference to chapter 18.790. 18.790 is explicitly cross referenced in the site Commentary 
development review submittal requirements. 
32. Cheryl Caines In the Tigard D owntown District This has been incorporated into the draft 18.610.010 
Tom McGuire D evelopment and D esign Urban Forestry Code Revisions. A cross Code & 
(11 -17-2011) Standards submittal requirements, reference to chapter 18.790 has been added to Commentary 
include a cross reference to section 18.610.010. Corresponding 
chapter 18.790. commentaty has been added to explain the 
-::: reason for the cross reference. 
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C h e r y l  C a i n e s  
T o m  M c G u i r e  
( 1 1 - 1 7 - 2 0 1 1 )  
C h e r y l  C a i n e s  
T o m  M c G u i r e  
( 1 1 - 1 7 - 2 0 1 1 )  
C h e r y l  C a i n e s  
T o m  M c G u i r e  
( 1 1 - 1 7 - 2 0 1 1 )  
S U M M A R I Z E D  C O M M E N T  
A d d  t o  t h e  a p p l i c a b i l i t y  s e c t i o n  o f  
t h e  c h a p t e r  1 8 . 7 4 5 ,  T y p e  I  M i n o r  
M o d i f i c a t i o n s  t o  c o n f o r m  t o  
c u r r e n t  p r a c t i c e .  F o r  e x a m p l e ,  
w h e n  r o o f t o p  m e c h a n i c a l  
e q u i p m e n t  i s  i n s t a l l e d  t h r o u g h  a  
T y p e  I  M i n o r  M o d i f i c a t i o n ,  s t a f f  
r e q u i r e s  s c r e e n i n g  o f  t h a t  
e q u i p m e n t  c o n s i s t e n t  w i t h  t h e  
s t a n d a r d s  i n  c h a p t e r  1 8 . 7 4 5 .  T h e  
a u t h o r i t y  t o  a p p l y  t h e s e  t y p e s  o f  
s t a n d a r d s  s h o u l d  c o n t i n u e .  
R e a r r a n g e  t h e  s t r e e t  t r e e  s t a n d a r d s  
s o  t h a t  t h e  f i r s t  s t a n d a r d  i n c l u d e s  
t h e  t y p e s  o f  p r o j e c t s  t h a t  a r e  
r e q u i r e d  t o  p l a n t  s t r e e t  t r e e s .  T h i s  
m a k e s  t h e  c o d e  m o r e  r e a d a b l e .  
R e v i s e  f o o t n o t e  [ 1 ]  o f  t a b l e  
1 8 . 7 4 5 . 2  b a c k  t o  i t s  o r i g i n a l  f o r m a t  
s o  t h a t  i t  i s  c o n s i s t e n t  w i t h  t h e  
c o d e  l a n g u a g e  i n  s e c t i o n  
1 8 . 7  4 5 . 0 5 0 . A . 2 .  
S T A F F  U P D A T E / R E S P O N S E  C O D E  
S E C T I O N  
T h i s  h a s  b e e n  i n c o r p o r a t e d  i n t o  t h e  d r a f t  1 8 . 7 4 5 . 0 2 0  
U r b a n  F o r e s t r y  C o d e  R e v i s i o n s .  T h e  p r o p o s e d  C o d e &  
a p p l i c a b i l i t y  g e n e r a l l y  c o n f o r m s  t o  c u r r e n t  
C o m m e n t a r y  
p r a c t i c e  b y  a p p l y i n g  t h e  s t a n d a r d s  t o  T y p e  I  
C o n d i t i o n a l  U s e  a n d  S i t e  D e v e l o p m e n t  R e v i e w  
M i n o r  M o d i f i c a t i o n s ,  a n d  T y p e  I I  a n d  I I I  l a n d  
u s e  r e v 1e w s .  
T h i s  h a s  b e e n  i n c o r p o r a t e d  i n t o  t h e  d r a f t  1 8 . 7 4 5 . 0 4 0  
U r b a n  F o r e s t r y  C o d e  R e v i s i o n s .  T h e  p r o j e c t  C o d e &  
t y p e s  t h a t  a r e  r e q u i r e d  t o  p l a n t  s t r e e t  t r e e s  a r e  C o m m e n t a r y  
l i s t e d  f i r s t  f o r  c o d e  r e a d a b i l i t y .  T h e  
c o m m e n t a r y  h a s  b e e n  m o d i f i e d  
c o r r e s p o n d i n g l y  t o  r e f l e c t  t h e  o r d e r  o f  t h e  
c o d e .  
T h i s  h a s  b e e n  i n c o r p o r a t e d  i n t o  t h e  d r a f t  
T a b l e  
U r b a n  F o r e s t r y  C o d e  R e v i s i o n s .  F o o t n o t e  [ 1 ]  
1 8 . 7 4 5 . 2  &  
h a s  b e e n  r e v i s e d  b a c k  t o  i t s  o r i g i n a l  f o r m a t  s o  C o m m e n t a r y  
t h a t  i t  i s  c o n s i s t e n t  w i t h  t h e  c o d e  l a n g u a g e  i n  
s e c t i o n  1 8 . 7 4 5 . 0 5 0 . A . 2 .  T h e  c o m m e n t a r y  h a s  
\)~en c o r r e s r > O n d i n g l y  r e v i s e d .  
i  
# COMMENTER SUMMARIZED COMMEN T STAFF UPDATE/RESPONSE CODE 
(DATE) SECTION 
36. Cheryl Caines Move the details of the use of the Tllis has been incorporated into the draft 18.790.030 
Tom McGuire tree canopy fee into a council Urban Forestry Code Revisions. T he activities Code& 
(11 -17-2011) resolution. D etailed specifications that the citizen advisory committee agreed the Commentary 
on the use of fees are more tree canopy fee should be used for have been 
appropriate in council resolutions removed from the code and replaced with a 
rather than code. cross reference to a council resolution (to be 
adopted concurrently with the urban forestry 
code revisions). T he commentary describing 
the activities the tree canopy should be used for 
has been left intact. Tills commentary will 
inform decision-makers of the citizen advisory 
committee's recommendations and be used by 
staff in drafting the resolution for council 
adoption. 
37. Cheryl Caines Allow setback adjustments for Tills has been incorporated into the draft 18.790.050 
Tom McGuire street side setbacks as well to Urban Forestry Code Revisions. Adjustments Code 
(11 -17-2011) preserve trees. Tills should be in are proposed for street side yard setbacks in 
addition to side and rear yard addition to side and rear setbacks to preserve 
setback adjustments. trees. The previous onlission of street side yard 
setback adjustments was an oversight. Adding it 
is not inconsistent \vith the recommendations 
of the citizen advisory committee to provide 
flexible standards for tree preservation. 
38. Cheryl Caines Move the details of the urban Tills has been incorporated into the draft 18.790.060 
Tom McGuire fores t inventory requirements into Urban Forestry Code Revisions. T he details of Code& 
(11 -17-2011) the urban forestry manual. the urban forest inventory requirements have Commentary 
been moved into Section 11 of the Urban Urban 
Forestry Manual \vith a cross reference Forestry 
provided in the code. The commentary has Manual 
been correspondingly revised to reflect the Section 11 
changes, and to illghlight the proposed fee for 
collecting the inventory data. 
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( D A T E )  
3 9 .  T o d d  P r a g e r  
( 1 1 - 1 8 - 2 0 1 1 )  
4 0 .  
T o d d  P r a g e r  
( 1 1 - 3 0 - 2 0 1 1 )  
S U M M A R I Z E D  C O M M E N T  S T A F F  U P D A T E / R E S P O N S E  C O D E  
S E C T I O N  
I n s e r t  C h a p t e r  1 8 . 3 1 0  ( S u m m a r y  T h i s  h a s  b e e n  i n c o r p o r a t e d  i n t o  t h e  d r a f t  1 8 . 3 1 0  
o f  L a n d  U s e  P e r m i t s )  i n t o  t h e  
U r b a n  F o r e s t r y  C o d e  R e v i s i o n s .  T h e  c h a p t e r  
C o d e &  
d r a f t  U r b a n  F o r e s u y  C o d e  
h a s  b e e n  i n s e r t e d  a n d  n o w  r e f l e c t s  t h e  u r b a n  C o m m e n t a r y  
R e v i s i o n s .  R e f l e c t  c h a n g e s  t o  t h e  f o r e s t r y  p e r m i t s  t h a t  h a v e  b e e n  a d d e d  a n d  
l a n d  u s e  p e r m i t s  f r o m  t h e  d r a f t  
d e l e t e d  i n  T i t l e  1 8 .  
U r b a n  F o r e s u y  C o d e  R e v i s i o n s .  
S t r i k e  t r e e  r e m o v a l  a d j u s t m e n t s  T h i s  h a s  b e e n  i n c o r p o r a t e d  i n t o  t h e  d r a f t  
1 8 . 3 7 0 . 0 2 0  
f r o m  s e c t i o n  1 8 . 3 7 0 . 0 2 0 . C . 9 .  
U r b a n  F o r e s t r y  C o d e  R e v i s i o n s  t o  c o r r e c t  t h e  C o d e &  
A d j u s t m e n t s  t o  d e v e l o p m e n t  
o v e r s i g h t .  C o r r e s p o n d i n g  c o m m e n t a r y  h a s  C o m m e n t a r y  
s t a n d a r d s  f o r  t r e e  p r e s e r v a t i o n  w i l l  
b e e n  a d d e d  t o  e x p l a i n  t h e  r e v i s i o n s .  
b e  a p p r o v e d  t h r o u g h  t h e  u r b a n  
f o r e s t r y  p l a n  c o m p o n e n t  o f  a  l a n d  
u s e  p e r m i t  a s  o u t l i n e d  i n  s e c t i o n  
1 8 . 7 9 0 . 0 5 0  ( F l e x i b l e  S t a n d a r d s  f o r  
P l a n t i n g  a n d  P r e s e r v a t i o n ) .  T h i s  i s  
c o n s i s t e n t  w i t h  t h e  c i t i z e n  a d v i s o r y  
c o m m i t t e e  c o n s e n s u s  
r e c o m m e n d a t i o n ,  a n d  t h e  s t r i k e o u t  
w a s  m i s s e d  d u r i n g  t h e  p r e v i o u s  
c o d e  r e v i s i o n s .  
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41. 
COMMENTER 
(DATE) 
Tom McGuire 
(12-1-2011) 
SUMMARIZED COMMENT 
The city has begun work on a 
project called the Regulatory 
Improvement Initiative. The 
purpose of the project is to revise, 
reorganize and reformat the Tigard 
D evelopment Code to limit 
internal conflicts, clarify 
provisions, and generally make the 
code easier to use. Chapter 18.790 
is the first chapter to be 
completely revised since the city 
began work on the Regulatory 
Improvement Initiative. Various 
edits to Chapter 18.790 are 
required for consistency with the 
Regulatory Improvement 
Initiative. These edits do no t 
change the substance of the 
chapter provisions. 
STAFF UPDATE/RESPONSE CODE 
SECTION 
This has been incorporated into the draft 18.790 
Urban Forestry Code Revisions. Requested Code& 
edits have been made including reordering Commentary 
provisions, shortening sentence length for Urban 
readability, and ensuring consistent use of Forestry 
terminology. Corresponding commentary has Manual 
been added to reflect the edits. Cross 
references in the Urban Forestry Manual have 
been updated consistent with the reordering of 
code provisions. 
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C O M M E N T E R  S U M M A R I Z E D  C O M M E N T  
( D A T E )  
C h e r y l  C a i n e s  V e r i f y  w i t h  t h e  C i t y  A t t o r n e y  t h a t  
( 1 2 - 8 - 2 0 1 1 )  
t h e  r e m o v a l  p e r m i t  p r o c e s s  f o r  
t r e e s  t h a t  w e r e  r e q u i r e d  w i t h  
d e v e l o p m e n t  ( C h a p t e r  8 .  1 4 )  
s u p e r s e d e s  t h e  p r e s e r v a t i o n  
r e q u i r e m e n t s  f o r  t r e e s  t h a t  w e r e  
r e c o r d e d  a s  p r e s e t v e d  o n  p r o p e r t y  
d e e d s  a s  r e q u i r e d  b y  p r i o r  l a n d  u s e  
d e c i s i o n s .  
S T A F F  U P D A T E / R E S P O N S E  
C O D E  
S E C T I O N  
T h i s  h a s  b e e n  i n c o r p o r a t e d  i n t o  t h e  8 . 1 4  
c o m m e n t a r y  f o r  t h e  d r a f t  U r b a n  F o r e s t r y  C o d e  
C o t n m e n t a r y  
R e v i s i o n s .  T h e  C i t y  A t t o r n e y  h a s  c o n f t r m e d  
t h a t  t h e  l e g i s l a t i v e  a m e n d m e n t s  i n  C h a p t e r  8 . 1 4  
s u p e r s e d e  t h e  p r e s e t v a t i o n  r e q u i r e m e n t s  f o r  
t r e e s  t h a t  w e r e  r e q u i r e d  b y  p r i o r  l a n d  u s e  
d e c i s i o n s .  T h i s  i n c l u d e s  t r e e s  t h a t  a r e  r e c o r d e d  
a s  p r e s e t v e d  o n  p r o p e r t y  d e e d s  a s  a  r e s u l t  o f  
p a s t  l a n d  u s e  d e c i s i o n s .  H o w e v e r ,  t h e  C i t y  
A t t o r n e y  r e c o m m e n d s  i n c l u d i n g  b o i l e r  p l a t e  
l a n g u a g e  w h e n  i s s u i n g  f u t u r e  t r e e  r e m o v a l  
p e r m i t s  t o  t h e  e f f e c t  t h a t :  " T h e r e  m a y  b e  a  
d e e d  r e s t r i c t i o n  o n  t h e  t r e e  a p p r o v e d  f o r  
r e m o v a l  b y  t h i s  d e c i s i o n .  W h i l e  t h e  a p p l i c a n t  i s  
s o l e l y  r e s p o n s i b l e  f o r  i d e n t i f y i n g  a n d  r e m o v i n g  
a n y  a p p l i c a b l e  d e e d  r e s t r i c t i o n s ,  t h e  c i t y  w i l l  
p r o v i d e  a n y  s i g n a t u r e s  n e c e s s a r y  t o  f a c i l i t a t e  
t h e  r e m o v a l  o f  d e e d  r e s t r i c t i o n s  f o r  t r e e s  
p e r m i t t e d  f o r  r e m o v a l  b y  t h i s  d e c i s i o n . "  
T h e  C i t y  A t t o r n e y  r e c o m m e n d s  a d d i n g  
l a n g u a g e  t o  t h e  c o m m e n t a r y  t h a t  a c k n o w l e d g e s  
t h e  l e g i s l a t i v e  i n t e n t  o f  C h a p t e r  8 . 1 4  i n  c r e a t i n g  
a  p r o c e s s  t h a t  s u p e r s e d e s  p r e s e t v a t i o n  
r e q u i r e m e n t s  o f  p a s t  l a n d  u s e  d e c i s i o n s ,  
i n c l u d i n g  t h o s e  f o r  t r e e s  w i t h  d e e d  r e s t r i c t i o n s .  
# COMMEN TER SUMMARIZED COMMEN T STAFF U PDATE/RESPONSE CODE 
(DATE) SECTION 
43. Keith J ehnke Need explanation that existing This has been incorporated into the draft Urban 
Peer Review Consultant trees under 6-inch DBH can be Urban Forestry Manual. The city may consider Forestry 
(12-8-2011) given "planted tree mature crown trees less than 6-inch DBH as equivalent to Manual 
area" if the tree is located with newly planted trees if they meet all applicable Section 10 
adequate rooting soil and is located species, size, condition and location 
within the specified distances from requirements as newly planted trees. 
other trees, existing buildings, etc. 
44. Keith J ehnke Are wetland areas included or No revisions were made based on this 18.120 
Peer Review Consultant excluded in to tal development site comment. Code 
(12-8-201 1) area calculations for requil:ed Urban 
canopy? The definition o f "development site" in Forestry 
Chapter 18.1 20 (Defmitions) is as follows: Manual 
Section 10 
"D evelopment site"- A lo t or combination of 
lots upon which one or more buildings and/ or 
other improvements are constructed. 
If a wetland area is part of the lot being 
developed, it is included in the development 
site area used to calculate effective canopy 
cover. 
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C O M M E N T E R  S U M M A R I Z E D  C O M M E N T  
( D A T E )  
K e i t h  J e h n k e  F o r  c a n o p y  c a l c u l a t i o n s ,  d o e s  a  
P e e r  R e v i e w  C o n s u l t a n t  t r e e  i n  t h e  c e n t e r  m e d i a n  a r e a  
( 1 2 - 8 - 2 0 1 1 )  
c o u n t  t o w a r d  t h e  t r e e  c a n o p y  a r e a ?  
S T A F F  U P D A T E / R E S P O N S E  
C O D E  
S E C T I O N  
C l a r i f y i n g  l a n g u a g e  b a s e d  o n  t h i s  c o m m e n t  h a s  U r b a n  
b e e n  i n c o r p o r a t e d  i n t o  t h e  d r a f t  U r b a n  
F o r e s t r y  
F o r e s t r y  M a n u a l .  
M a n u a l  
S e c t i o n  1 0  
T h e  i n t e n t  o f  t h e  d r a f t  U r b a n  F o r e s t r y  M a n u a l  
i s  t o  n o t  g r a n t  c a n o p y  c r e d i t  f o r  m e d i a n  t r e e s  
b e c a u s e  t h e y  a r e  t h e  m a i n t e n a n c e  r e s p o n s i b i l i t y  
o f  t h e  c i t y ,  a n d  i t  w o u l d  b e  d i f f i c u l t  t o  
d e t e r m i n e  w h i c h  p a r c e l  o n  w h i c h  s i d e  o f  a  
s t r e e t  w o u l d  r e c e i v e  c r e d i t  f o r  a  m e d i a n  t r e e  
( p a r t i c u l a r l y  w h e n  t h e  p a r c e l s  a r e  u n d e r  
s e p a r a t e  o w n e r s h i p ) .  
# COMMEN TER SUMMARIZED COMMEN T STAFF U PDATE/RESPONSE CODE 
(DATE) SECTION 
46. Keith J ehnke D efine method for exis ting canopy No revisions were made based on this Urban 
Peer Review Consultant area calculations. Po tential options comment. T he methods for calculating existing Forestry 
(12-8-2011) would include by formula using canopy area are detailed in the Urban Forestry Manual 
DBH, by aerial pho to Manual. Section 10 
interpretation, or by survey. 
For open grown trees, the method for 
calculating existing canopy is: 
Average tree canopy area= (average tree 
canopy spread / 2/ x n 
For stands o f trees, the method for calculating 
exis ting canopy is: 
The total on site tree canopy area (in square 
feet) o f the stand 
The project arborist would be required to 
determine the stand canopy area (measured at 
the dripline o f the stand). The most efficient 
method would likely be aerial photo 
interpretation. However, any method that 
accurately captures the stand canopy dripline 
area would be accepted. 
47. Keith J ehnke The list of acceptable trees seems No revisions were made based on this Urban 
Peer Review Consultant limiting in som e situations. Is comment. T he various tree lists (except the Forestry 
(12-8-2011) there a procedure for accepting Nuisance T ree List) include trees that are Manual 
trees not on the list? known to perform well in the Portland area. Sections 2, 
However, the Urban Forestry Manual states 4, 7, 8, 10, 
that the City Manager or designee may review and 13 
and approve alternate trees not on any of the 
lists on a case by case basis. 
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4 8 .  
4 9 .  
C O M M E N T E R  
( D A T E )  
K e i t h  . J  e h n k e  
P e e r  R e v i e w  C o n s u l t a n t  
( 1 2 - 8 - 2 0 1 1 )  
K e i t h  . J  e h n k e  
P e e r  R e v i e w  C o n s u l t a n t  
( 1 2 - 8 - 2 0 1 1 )  
S U M M A R I Z E D  C O M M E N T  
W i t h i n  p a r k i n g  l o t s ,  i s  i t  n e c e s s a r y  
t o  c a l c u l a t e  t h e  p e r c e n t  c a n o p y  
c o v e r  o v e r  t h e  p a r k i n g  l o t  f o r  e a c h  
i n d i v i d u a l  t r e e  ( a s  o p p o s e d  t o  
c a l c u l a t i n g  t h e  t o t a l  c a n o p y  c o v e r  
o v e r  t h e  p a r k i n g  l o t ) ?  T h i s  a d d s  
a n  a d d i t i o n a l  s t e p  a n d  i s  t i m e  
c o n s u r r u n g .  
S h o w i n g  s o i l  v o l u m e s  o n  t h e  s a m e  
p l a n  a s  t h e  T r e e  C a n o p y  S i t e  P l a n  
m a k e s  t h e  s h e e t  c r o w d e d  a n d  h a r d  
t o  r e a d .  O n  a  v e r y  l a r g e  s i t e ,  i t  
s e e m s  t h a t  t h i s  m i g h t  b e  b e t t e r  a s  a  
s e p a r a t e  s h e e t .  A l s o ,  w e  d i d n ' t  d o  
t h i s  o n  a l l  s i x  s i t e s  p e r  y o u r  
i n s t r u c t i o n .  I s  t h e r e  a  
s t a n d a r d /  g u i d e l i n e  f o r  w h e n  i t  
s h o u l d  b e  s h o w n ?  
S T A F F  U P D A T E / R E S P O N S E  
C O D E  
S E C T I O N  
T h i s  h a s  b e e n  i n c o r p o r a t e d  i n t o  t h e  d r a f t  
U r b a n  
U r b a n  F o r e s t r y  M a n u a l .  T h e  p a r k i n g  l o t  
F o r e s t r y  
c a n o p y  s t a n d a r d  i s  b a s e d  o n  t h e  c u m u l a t i v e  
M a n u a l  
p e r c e n t  c a n o p y  c o v e r  f o r  a l l  t r e e s  o v e r  t h e  
S e c t i o n  1 3  
e n t i r e  p a r k i n g  a r e a .  T h e  r e q u i r e m e n t  t o  
c a l c u l a t e  t h e  p e r c e n t  c a n o p y  c o v e r  o v e r  t h e  
p a r k i n g  a r e a  f o r  e a c h  i n d i v i d u a l  t r e e  i s  n o t  
n e c e s s a r y ,  a n d  h a s  b e e n  s t r u c k  f r o m  t h e  
m a n u a l .  
N o  r e v i s i o n s  w e r e  m a d e  b a s e d  o n  t h i s  
U r b a n  
c o m m e n t .  S o i l  v o l u m e s  a r e  o n l y  r e q u i r e d  t o  b e  
F o r e s t r y  
d i s p l a y e d  f o r  s t r e e t  t r e e s  a n d  p a r k i n g  l o t  t r e e s  M a n u a l  
o n  t h e  S o i l  V o l u m e  P l a n  a n d  P a r k i n g  L o t  T r e e  
S e c t i o n s  1 2  
C a n o p y  P l a n ,  r e s p e c t i v e l y .  S o i l  v o l u m e s  m a y  a n d  1 3  
b e  d i s p l a y e d  o n  s e p a r a t e  p l a n  s h e e t s  f o r  c l a r i t y .  
# COMMENTER SUMMARIZED COMMENT STAFF UPDATE/RESPONSE CODE 
(DATE) SECTION 
50. Tom McGuire Reword the language allowing a This has been incorporated into the draft 18.790.050 
Susan Hartnett reduction in minimum density for Urban Forestry Code Revisions. The term Code 
(12-12-2011) the preservation of significant tree "number o f units" has been changed to 
groves in section 18. 790.050.C.1. " density" for accuracy and consistency with the 
T he current language allows a language in Chapter 18.510. 
reduction in the "number of 
units", but it would be more More specific cross references have been made 
accurate to allow a reduction in to section 18.51 0.040.B and Chapter 18.715 to 
" density". make the code easier to navigate. 
Also, cross reference the specific 
code section in Chapter 18.510 to 
make it easier to find information 
on density calculations (section 
18.51 0.040.B). 
Finally cross reference Chapter 
18.715 (Density Computations) 
because it contains additional 
information on density 
calculations. 
51. Tom McGuire Section 18.790.050.D .1 allows a T his has been incorporated into the draft 18.715.020 
Susan Hartnett reduction in minimum density for Urban Forestry Code Revisions. Section Code& 
(12-12-2011) the preservation of a significant 18. 715.020.A.1 has been revised to reflect the Commentary 
tree grove. This allowed reduction allowed reduction in minimum density for the 
in minimum density should be preservation of a significant tree grove. 
reflected in Chapter 18.715 Commentary has been added to explain the 
(Density Computations). . . rev1s1ons. 
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#  I  C O M M E N T E R  
( D A T E )  
5 2 .  I  T o m  M c G u i r e  
S u s a n  H a r t n e t t  
( 1 2 - 1 2 - 2 0 1 1 )  
5 3 .  I  T o m  M c G u i r e  
S u s a n  H a r t n e t t  
( 1 2 - 1 2 - 2 0 1 1 )  
S U M M A R I Z E D  C O M M E N T  
I n c o r p o r a t e  t h e  e n f o r c e m e n t  
p r o v i s i o n s  a n d  p e n a l t i e s  i n  T i t l e  8  
a n d  C h a p t e r  1 8 . 7 9 0  i n t o  T i t l e  6  
a n d  C h a p t e r  1 . 1 6  r e s p e c t i v e l y .  
T i t l e  6  a n d  C h a p t e r  1 . 1 6  a r e  w h e r e  
e n f o r c e m e n t  p r o v i s i o n s  a n d  
p e n a l t i e s  t h r o u g h o u t  t h e  c o d e  a r e  
c o n s o l i d a t e d .  T h i s  i s  w h e r e  
e n f o r c e m e n t  p r o v i s i o n s  a n d  
p e n a l t i e s  f o r  u r b a n  f o r e s t r y  
v i o l a t i o n s  s h o u l d  b e  c o n s o l i d a t e d .  
C r o s s  r e f e r e n c e  T i t l e  6  a n d  
C h a p t e r  1 . 1 6  i n  C h a p t e r  8 . 2 0  
( E n f o r c e m e n t ) .  R e t a i n  t h e  a b i l i t y  
t o  p l a c e  s t o p  w o r k  o r d e r s  a n d  
r e q u i r e  r e t r o a c t i v e  t r e e  r e m o v a l  
p e r m i t s  i n  C h a p t e r  8 . 2 0  s i n c e  
t h o s e  p r o v i s i o n s  a r e  n o t  i n  T i t l e  6  
o r  C h a p t e r  1 . 1 6 .  
R e m o v e  t h e  p r o v i s i o n  i n  s e c t i o n  
1 8 . 7 9 0 . 0 8 0  ( E n f o r c e m e n t )  
r e q u i r i n g  t h e  c i t y  t o  f l l e  a n  e t h i c s  
c h a r g e  s t a t e m e n t  i f  a  c e r t i f i e d  
a r b o r i s t  s u b m i t s  f a l s e  o r  
m i s l e a d i n g  i n f o r m a t i o n .  T h e  c i t y  
c o u l d  s t i l l  r e s e r v e  t h e  r i g h t  t o  f l l e  
a n  e t h i c s  c h a r g e  s t a t e m e n t ,  b u t  f o r  
l i a b i l i t y  r e a s o n s ,  t h e  c i t y  s h o u l d  n o t  
b e  o b l i g a t e d  t o  d o  s o .  
S T A F F  U P D A T E / R E S P O N S E  
T h i s  h a s  b e e n  i n c o r p o r a t e d  i n t o  t h e  d r a f t  
U r b a n  F o r e s t r y  C o d e  R e v i s i o n s .  T h e  
e n f o r c e m e n t  p r o v i s i o n s  a n d  p e n a l t i e s  ( a n d  
c o r r e s p o n d i n g  c o m m e n t a r y )  t h a t  w e r e  
p r e v i o u s l y  i n  C h a p t e r  8 . 2 0  a n d  S e c t i o n  
1 8 . 7 9 0 . 0 8 0  h a v e  b e e n  i n c o r p o r a t e d  i n t o  T i t l e  6  
a n d  C h a p t e r  1 . 1 6 .  S e c t i o n  6 . 0 2 . 1 8 0  n o w  
d e s c r i b e s  w h a t  c o n s t i t u t e s  v i o l a t i o n s  o f  T i t l e  8  
a n d  C h a p t e r  1 8 . 7 9 0 .  S e c t i o n  1 . 1 6 . 6 4 0  n o w  
d e s c r i b e s  t h e  p e n a l t i e s  f o r  v i o l a t i o n s  o f  T i t l e  8  
a n d  C h a p t e r  1 8 . 7 9 0 .  C h a p t e r  8 . 2 0  n o w  c r o s s  
r e f e r e n c e s  T i t l e  6  a n d  C h a p t e r  1 . 1 6 .  C h a p t e r  
8 . 2 0  s t i l l  r e t a i n s  t h e  a b i l i t y  t o  p l a c e  s t o p  w o r k  
o r d e r s  a n d  r e q u i r e  r e t r o a c t i v e  t r e e  r e m o v a l  
p e r m i t s .  C o m m e n t a r y  f o r  C h a p t e r  8 . 2 0  h a s  
b e e n  r e v i s e d  t o  r e f l e c t  t h e  c h a n g e s .  P r e v i o u s  
c r o s s  r e f e r e n c e s  t h r o u g h o u t  t h e  c o d e  t o  
e n f o r c e m e n t  p r o v i s i o n s  a n d  p e n a l t i e s  i n  
C h a p t e r  8 . 2 0  a n d  S e c t i o n  1 8 . 7 9 0 . 0 8 0  h a v e  b e e n  
c o r r e c t e d .  
T h i s  h a s  b e e n  i n c o r p o r a t e d  i n t o  t h e  d r a f t  
U r b a n  F o r e s u - y  C o d e  R e v i s i o n s .  T h e  p r o v i s i o n  
r e q u i r i n g  t h e  c i t y  t o  f t l e  a n  e t h i c s  c h a r g e  
s t a t e m e n t  h a s  b e e n  r e m o v e d .  C o r r e s p o n d i n g  
c o m m e n t a r y  h a s  a l s o  b e e n  r e m o v e d .  
C O D E  
S E C T I O N  
1 . 1 6 . 1 8 0  
6 . 0 2 . 1 8 0  
8 . 2 0  
C o d e &  
C o m m e n t a r y  
1 8 . 7 9 0 . 0 8 0  
C o d e &  
C o m m e n t a r y  
# COMMENTER SUMMARIZED COMMENT STAFF UPDATE/RESPONSE CODE 
(DATE) SECTION 
54. Todd Prager T itle 6 (Nuisance Violations) is a This has been incorporated into the draft 6.01.020 
(12-15-2011) new title in draft phase that has Urban Forestry Code Revisions. H azard trees 6.02.030 
not yet been adopted as of the are addressed in a comprehensive way through 6.04.040 
writing of this comment Chapter 8.08 and replace the existing Code& 
(December 15, 2011). However, provisions in Sections 6.01.020, 6.02.030, and Commentary 
in anticipation of its adoption in 6.04.040 that lack sufficient clarity for hazard 
advance of the adoption of the tree evaluation and abatement. T hese are the 
Urban Forestry Code Revisions, it same revisions that were made to Sections 
is included as part of this package 7.40.050, 7.40.060, and 7.40.090. 
of amendments. Corresponding commentary for the revisions to 
Title 7 have been incorporated into Title 6. 
Exis ting code language referencing 
hazard trees that was revised in 
Sections 7.40.050, 7.40.060, and 
7.40.090 has been duplicated and 
moved to Title 6. The same 
revisions to the hazard tree 
language in T itle 7 are required in 
Title 6. 
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C O M M E N T E R  
( D A T E )  
D a r r e n  W y s s  
C h e r y l  C a i n e s  
T o d d  P r a g e r  
( 1 2 - 1 9 - 2 0 1 1 )  
S U M M A R I Z E D  C O M M E N T  S T A F F  U P D A T E / R E S P O N S E  
C O D E  
S E C T I O N  
S e c t i o n  1 8 . 5 2 0 . 0 5 0 . C  1  l i m i t s  t h e  T h i s  h a s  b e e n  i n c o r p o r a t e d  i n t o  t h e  d r a f t  
1 8 . 7 9 0 . 0 5 0  
m a x i m u m  f l o o r  a r e a  r a t i o  ( F A R )  i n  U r b a n  F o r e s t r y  C o d e  R e v i s i o n s .  S e c t i o n  
C o d e &  
t h e  M U E  z o n e  t o  . 4 .  T h e  p u r p o s e  1 8 . 7 9 0 . 0 5 0 . 0 . 3  n o w  s p e c i f i e s  t h a t  2 0  f e e t  
C o m m e n t a r y  
i s  t o  l i m i t  i m p a c t s  o n  s t a t e  h i g h w a y  a d d i t i o n a l  b u i l d i n g  h e i g h t  i s  a l l o w e d  p r o v i d e d  
f a c i l i t i e s .  t h a t  m a x i m u m  F A R  i n  t h e  M U E  z o n e  i s  n o t  
e x c e e d e d .  C o m m e n t a r y  h a s  b e e n  a d d e d  t o  
I t  i s  u n c l e a r  w h e t h e r  t h e  a l l o w e d  e x p l a i n  t h e  p r o v i s i o n .  
i n c r e a s e  i n  c o m m e r c i a l  b u i l d i n g  
h e i g h t  f o r  t r e e  g r o v e  p r e s e r v a t i o n  
( S e c t i o n  1 8 . 7 9 0 . 0 5 0 . 0 . 3 )  w o u l d  
s u p e r s e d e  t h e  m a x i m u m  F A R  i n  
t h e  M U E  z o n e .  I t  s h o u l d  b e  
c l a r i f i e d  t h a t  w h i l e  i n c r e a s i n g  
b u i l d i n g  h e i g h t  i n  t h e  M U E  z o n e  
i s  a l l o w e d  f o r  t r e e  g r o v e  
p r e s e r v a t i o n ,  e x c e e d i n g  t h e  F A R  
l i n u t  i s  n o t .  T h i s  w i l l  c o n t i n u e  
e x i s t i n g  p o l i c y  t o  l i m i t  i m p a c t s  o n  
s t a t e  h i g h w a y  f a c i l i t i e s .  
# COMMENTER SUMMARIZED COMMENT STAFF UPDATE/RESPONSE CODE 
(DATE) SECTION 
56. Darren Wyss Remove from the commentary for This has been incorporated into the 18.790.050 
(12-19-2011) the commercial and industrial tree commentary for the draft Urban Forestry Code Commentary 
grove preservation incentives Revisions. Reference to 20 feet of additional 
(Sections 18.790.050.3 and 4) building height being equal to "1 story" has 
reference to 20 feet of additional been removed from the commentary for 
building height being equal to " 1 Sections 18.790.050.3 and 4. 
story". T he incentive is to simply 
allow 20 feet additional building 
height for tree grove preservation. 
The incentive does not necess,arily 
guarantee an additional story. 
Whether an additional story is 
possible from an additional 20 feet 
of building height depends on the 
circumstances and constraints of a 
particular site. 
57. Susan H artnett In the commentary, reference the This has been incorporated into the 8.04 
(12-20-2011) "guiding principles" for each code commentary for the draft Urban Forestry Code 8.08 
topic area. This will allow people Revisions. The "guiding principles" are cross 18.790 
reviewing the code to cross referenced at the beginning of each code topic 18.790.050 
reference the guiding principles area. Commentary 
that relate to each code topic area. 
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1 .  J o h n  F r e w i n g  
( 1 2 - 8 - 2 0 1 1 )  
P u b l i c  I n p u t  
S U M M A R I Z E D  C O M M E N T  
S T A F F  U P D A T E / R E S P O N S E  
C O D E  
S E C T I O N  
A r e  t r e e  p e r m i t  s t a n d a r d s  c l e a r  a n d  N o  r e v i s i o n s  w e r e  m a d e  b a s e d  o n  t h i s  
8 . 0 4  
o b j e c t i v e ?  
c o m m e n t .  T h e r e  a r e  t w o  t r a c k s  o f  d e c i s i o n  
C o d e  
m a k i n g  f o r  t r e e  p e r m i t s :  
1 .  T h e  a d m i n i s t r a t i v e  r e v i e w  p r o c e s s  b y  
c i t y  s t a f f  i s  f o r  s i m p l e  s i t u a t i o n s  s u c h  a s  
t r e e s  t h a t  a r e  i n  p o o r  o r  h a z a r d o u s  
c o n d i t i o n ,  n u i s a n c e  t r e e s ,  c a u s i n g  
d a m a g e ,  f l r e  d a n g e r s  o r  p r e v e n t i n g  
a l l o w e d  d e v e l o p m e n t  t o  o c c u r  ( e x c e p t  
h e r i t a g e  t r e e s ) .  T h e  p e r m i t  c r i t e r i a  f o r  
t h i s  p r o c e s s  a r e  c l e a r  a n d  o b j e c t i v e .  
2 .  
T h e  p u b l i c  r e v i e w  p r o c e s s  b y  a  
d e s i g n a t e d  b o a r d  o r  c o m m i s s i o n  i s  f o r  
m o r e  c o m p l e x  s i t u a t i o n s  w h e r e  t h e  
I  
r e a s o n s  f o r  r e m o v a l  a r e  l e s s  c l e a r .  T h e  
d e s i g n a t e d  b o a r d  o r  c o m m i s s i o n  i s  
a u t h o r i z e d  t o  u s e  t h e i r  d i s c r e t i o n  t o  
w e i g h  t h e  t r e e  b e n e f i t s  a n d  r e a s o n s  f o r  
r e m o v a l  w h e n  m a k i n g  t h e i r  d e c i s i o n .  
T h e  p e r m i t  c r i t e r i a  f o r  t h i s  p r o c e s s  a r e  
d i s c r e t i o n a r y .  
T h e  c i t y  a t t o r n e y  h a s  r e v i e w e d  a n d  a p p r o v e d  
t h e  p r o c e s s  a n d  s t a n d a r d s  f o r  b o t h  o f  t h e s e  
p e r m i t  t y p e s .  
# COMMENTER SUMMARIZED COMMENT STAFF UPDATE/RESPONSE CODE 
(DATE) SECTION 
2. John Frewing Have all tree permit definitions in No revisions were made based on this 8.02.030 
(12-8-2011) one place. Cross reference if comment. A new Chapter 8.02 (Definitions Code 
necessary. and Rules) contains all tree related definitions 
that can be cross referenced during the tree 
permitting process. Previously, tree related 
definitions were in various parts of the code 
and now they are consolidated. 
3. John Frewing Calculate canopy cover as: No revisions were made based on this Urban 
(12-8-2011) comment. Throughout the Urban Forestry Forestry 
Sum of effective canopy area in Code Revisions process, the canopy cover Manual 
site development area + total site standards were applied based on the overall Section 10 
development area development site area and not limited to just 
the disturbed portion of the development site. 
For commercial and industrial Staff and outside consultants tested the canopy 
zoned areas, allow as an cover standards based on the overall 
alternative: development site and determined they result in 
a reasonable amount of planting and 
Sum of canopy area on whole site preservation. The Citizen and Technical 
+ total site area Advisory Committees also reviewed the results 
of applying the canopy cover standards based 
on the overall development site and the general 
consensus was the results were reasonable. 
Staff does not recommend modifying the 
canopy cover calculations without significant 
technical and public review of the implications. 
4. John Frewing Clarify the defmitions of 'open No revisions were made based on this 18.1 20 
(12-8-201 1) space', 'green space', 'natural area', comment. Clarification of these defmitions is Code 
etc. out of scope for the Urban Forestry Code 
Revisions process because it would extend 
beyond trees. 
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5 .  
J o h n  F r e w i n g  
( 1 2 - 8 - 2 0 1 1 )  
6 .  J o h n  F r e w i n g  
( 1 2 - 8 - 2 0 1 1 )  
7 .  
K e n  G e r t z  
( 1 2 - 8 - 2 0 1 1 )  
S U M M A R I Z E D  C O M M E N T  
M a t u r e  t r e e  c a n o p y  a r e a  s h o u l d  b e  
r e d u c e d  f o r :  
1 .  I n t e r f e r e n c e  w i t h  b u i l d i n g  
f o o t p r i n t ,  a n d ;  
2 .  
L o c a t i o n  u n d e r  p o w e r  o r  
c o m m u n i c a t i o n s  c a b l e s .  
M a k e  t e r m i n o l o g y  c o n s i s t e n t  
b e t w e e n  ' r e q u i r e m e n t s '  
( 1 8 . 3 6 0 . 0 9 0 . A . 1 )  a n d  ' s t a n d a r d s '  
( U r b a n  F o r e s t r y  M a n u a l  S e c t i o n  1 0  
P a r t  3 . N )  
D o e s  t h e  c o d e  g i v e  c r e d i t  f o r  
o v e r l a p p i n g  t r e e  c a n o p y ?  
S T A F F  U P D A T E / R E S P O N S E  
C O D E  
S E C T I O N  
N o  r e v i s i o n s  w e r e  m a d e  b a s e d  o n  t h i s  
U r b a n  
c o m m e n t .  T h e  t r e e  p l a c e m e n t  r e q u i r e m e n t s  
F o r e s t r y  
a c c o u n t  f o r  t h e s e  c o n f l i c t s  b y :  M a n u a l  
1 .  
R e q u i r i n g  s e t b a c k s  f r o m  b u i l d i n g  S e c t i o n  1 0  
f o o t p r i n t s  b a s e d  o n  m a t u r e  c a n o p y  
s p r e a d ,  a n d ;  
2 .  R e q u i r i n g  t r e e s  t h a t  w i l l  n o t  i n t e r f e r e  
w i t h  o v e r h e a d  u t i l i t y  l i n e s  a t  f u l l  
m a t u r i t y .  
N o  r e v i s i o n s  w e r e  m a d e  b a s e d  o n  t h i s  1 8 . 7 9 0 . 0 3 0  
c o m m e n t .  T h e  t e r m  ' r e q u i r e m e n t '  i s  a  b r o a d  
C o d e  
t e r m  t h a t  e n c o m p a s s e s  t h e  t e r m  ' s t a n d a r d ' .  U r b a n  
T h e  ' s t a n d a r d s '  i n  t h e  u r b a n  f o r e s t r y  m a n u a l  a r e  
F o r e s t r y  
a p p l i c a b l e  t o  t h e  l a n d  u s e  r e v i e w s  l i s t e d  i n  M a n u a l  
s e c t i o n  1 8 . 7 9 0 . 0 2 0 .  
N o  r e v i s i o n s  w e r e  m a d e  b a s e d  o n  t h i s  
U r b a n  
c o m m e n t .  T h e  t r e e  p l a c e m e n t  r e q u i r e m e n t s  F o r e s t r y  
l i m i t  c a n o p y  o v e r l a p  b y  r e q u i r i n g  s p a c i n g  
M a n u a l  
b e t w e e n  t r e e s  b a s e d  o n  m a t u r e  c a n o p y  s p r e a d .  
S e c t i o n  1 0  
H o w e v e r ,  i n  s o m e  c a s e s  t h e r e  w o u l d  s t i l l  b e  
s o m e  c a n o p y  o v e r l a p  t h a t  w o u l d  r e c e i v e  c r e d i t .  
P a r t  o f  t h e  r e a s o n  f o r  g r a n t i n g  c r e d i t  f o r  s o m e  
o v e r l a p p i n g  t r e e  c a n o p y  i s  t o  n o t  o v e r l y  
c o m p l i c a t e  t h e  c a l c u l a t i o n  m e t h o d s .  A l s o ,  i n  
r e a l i t y ,  t r e e  c a n o p y  d o e s  n o t  n e c e s s a r i l y  o v e r l a p .  
I n s t e a d ,  t r e e  c a n o p y  g r o w s  t o w a r d s  e m p t y  
s p a c e s  r e s u l t i n g  i n  s i m i l a r  c a n o p y  a r e a  b u t  w i t h  
a s y m m e t r i c a l  s h a p e s .  T h e  e x c e p t i o n  t o  t h i s  i s  
u n d e r s t o r y  t r e e s ,  b u t  t h e  d r a f t  s t a n d a r d s  r e q u i r e  
e x h a u s t i n g  t h e  p l a n t i n g  o f  o v e r s t o r y  t r e e s  
b e f o r e  p l a n t i n g  u n d e r s t o r y  t r e e s .  
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8. 
9. 
COMMENTER 
(DATE) 
Ken Gertz 
(12-8-201 1) 
Anonymous 
(12-8-2011) 
SUMMARIZED COMMENT 
Please provide the same drawings 
for the same sites if there were no 
exis ting trees. 
Overall, the code seems flexible. 
However, there should be more 
screening required between 
developments . 
STAFF UPDATE/RESPONSE CODE 
SECTION 
N o revisions were made based on this Urban 
comment. The peer review project sites were Fores try 
selected because they represent the typical Manual 
range of development projects in Tigard. O nly Section 10 
one project (Master's Partition) has a significant 
number of existing trees. Otherwise, the 
project sites had very few exis ting trees and one 
site had no exis ting trees (Sequoia Landing). 
The objective o f the peer review was to test the 
draft code for workability on actual projects. 
Modifying site conditions by removing (or 
adding) trees was not part of the scope of work 
and not within the current budget for the peer 
review. H owever, if the existing trees were 
removed from the project sites, the tree canopy 
standards would likely be met through some 
additional planting. 
No revisions were made based on this 18.745.050 
comment. Screening between incompatible Code 
developments is required by section 18.745.050 
(Buffering and Screening). No screening is 
required between similar developments and the 
Citizen Advisory Committee did not 
recommend it. 
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R e s i d e n t s  s h o u l d  n o t  h a v e  t o  p a y  
( 1 2 - 9 - 2 0 1 1 )  
f o r  a  h a z a r d  t r e e  e v a l u a t i o n  b y  t h e  
c i t y .  
S T A F F  U P D A T E / R E S P O N S E  
C O D E  
S E C T I O N  
N o  r e v i s i o n s  w e r e  m a d e  b a s e d  o n  t h i s  
U r b a n  
c o m m e n t .  T h e  C i t i z e n  A d v i s o r y  C o m m i t t e e  
F o r e s t r y  
s p e c i f i c a l l y  a d d r e s s e d  t h e  c o s t  r e c o v e r y  i s s u e  i n  M a n u a l  
t h e i r  g u i d i n g  p r i n c i p l e s .  G u i d i n g  p r i n c i p l e  7  f o r  S e c t i o n  1  
h a z a r d  t r e e s  s t a t e s :  
" R e c o v e r  c o s t s  i n c u r r e d  b y  t h e  c i t y  w h e n  
p a r t i e s  r e l y  o n  t h e  f o r m a l  c i t y  p r o c e s s  f o r  
r e s o l v i n g  h a z a r d  t r e e  i s s u e s .  T h e  p u b l i c  s h o u l d  
n o t  h a v e  t o  b e a r  t h e  f u l l  c o s t  f o r  i s s u e s  t h a t  
s h o u l d  b e  r e s o l v e d  w i t h o u t  c i t y  i n v o l v e m e n t . "  
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# COMMENTER SUMMARIZED COMMENT STAFF UPDATE/RESPONSE CODE 
(DATE) SECTION 
11. Fanny Bookout Trees should not be required in No revisions were made based on this 18.745.050 
(12-9-2011) parking lots because of leaf clean comment. The Citizen Advisory Committee Code 
up and safety issues. consensus was to implem ent the Urban 
recommendations o f the Urban Forestry Forestry 
Master P lan to increase tree canopy over Manual 
parking lo ts. Section 13 
Parking lo ts represent opportunity areas to 
significant increase tree canopy citywide and 
m eet the city's long term canopy goals. Trees 
in parking lots also provide benefits such as 
shading, stormwater interception, air quality 
improvement, and carbon sequestration. 
Studies in the Pacific orthwest that compare 
these benefits to costs (leaf clean up, pruning, 
watering, etc.) have found large canopy trees 
provide an annual net benefit ranging from 
$46.81 to $51.46. 1 
Also, recent studies in Portland show that trees 
with high canopies (such as those on the 
parking lot tree list) are actually associated with 
reduced crime levels.2 
1 McPherson, E.G., S.E. Maco,J.R. Simpson, P.J. Peper, Q. Xiao, A. VanDerZanden, and N. Bell. 2002. Western Washington and Oregon 
Community Tree Guide: Benefits, Costs, and Strategic Planting. International Society of Arboriculture, Pacific Northwest Chapter, 
Silverton, O R. 
2 Donovan, G .H. and J. Prestenmon. 2010. The Effect of Trees on Crime in Portland, Oregon. Environment and Behavior: Published online before 
print, 1-28. 
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1 2 .  I  J  o l m  r  r e w i n g  
( 1 2 - 1 2 - 2 0 1 1 )  
S U M M A R I Z E D  C O M M E N T  
I  d o n ' t  s e e  h o w  t h e r e  a r e  ' a p p r o v a l  
c r i t e r i a '  r e g a r d i n g  t r e e  c a n o p y  
c o v e r  f o r  m o s t  d e v e l o p m e n t  
s i t u a t i o n s .  ' A p p r o v a l  C r i t e r i a '  a r e  
i n  t h e r e  f o r  t h e  o p t i o n a l  s u b j e c t i v e  
o p t i o n  f o r  a n  u r b a n  f o r e s t  p l a n ,  
b u t  j u s t  t r y  t o  f o l l o w  t h e  t r a i l  f o r  
t h i n g s  l i k e  a  C U P  o r  S D R  t o  f i n d  
w h a t  ' a p p r o v a l  c r i t e r i a '  a p p l y .  I  
t h i n k  s t a t e  l a w / r e g u l a t i o n s  c a l l  f o r  
' c l e a r  a n d  o b j e c t i v e '  s t a n d a r d s  - -
n o t  f o u n d  h e r e  - - i t  i s  l e f t  u p  t o  t h e  
c i t y  t o  d e c i d e  w h a t e v e r  i t  w a n t s  a s  
' a p p l i c a b l e '  s e c t i o n s  o f  t h e  c o d e .  
S e e  O R S  2 2 7 . 1 7 3 ( 1 ) .  P l e a s e  
a d d r e s s  c l e a r l y  i n  c o m m e n t a r y  o r  
Q /  A  t o  t h e  p u b l i c  g o i n g  f o r w a r d .  
T h e  c a n o p y  ' s t a n d a r d s '  a r e  
c o n t a i n e d  i n  s u b m i t t a l  
' r e q u i r e m e n t s '  w h i c h  m a y  b e  
' a p p l i c a b l e '  i n  t h e  c o d e  ' a p p r o v a l  
c r i t e r i a '  f o r  C U P  a n d  S D R  
s e c t i o n s .  T h e  t a b l e  o f  ' a p p r o v a l  
c r i t e r i a '  i n  1 8 . 3 1 0  m e r e l y  p o i n t  t o  
1 8 . 3 3 0 . 0 3 0  a n d  1 8 . 3 6 0 . 0 9 0 .  L U B r \  
h a s  r u l e d  i n  M c C o n n e l l  v .  C i t y  o f  
W e s t  L i n n  1 7  O r L U B A  5 0 2  ( 1 9 8 9 )  
t h a t  f a i l u r e  t o  m e e t  s u b m i t t a l  
r e q u i r e m e n t s  i s  n o t  i n  i t s e l f  a  b a s i s  
f o r  r e m a n d  o r  d i s a p p r o v a l  o f  c i t y  
a c t i o n s .  I n  t h e  r e c e n t  F i e l d s  
a p p l i c a t i o n  f o r  e x t e n s i o n  o f  W a l l  
S T A F F  U P D A T E / R E S P O N S E  
N o  r e v i s i o n s  w e r e  m a d e  b a s e d  o n  t h i s  
c o m m e n t .  C h a p t e r  1 8 . 7 9 0  ( a n d  t h e  m o r e  
d e t a i l e d  U r b a n  F o r e s t r y  M a n u a l )  c o n t a i n s  t r e e  
c a n o p y  c o v e r  s t a n d a r d s  t h a t  a r e  r e q u i r e d  t o  b e  
m e t  f o r  a  l i s t  o f  T y p e  I I  a n d  I I I  l a n d  u s e  
p e r m i t s  ( C U P ,  D D R ,  M L P ,  P D ,  S L R ,  S D R ,  
a n d  S U B ) .  T h i s  i s  c l e a r l y  s t a t e d  i n  s e c t i o n  
1 8 . 7 9 0 . 0 2 0 . A .  T h e  a p p r o v a l  c r i t e r i a  i n  t h e  
c h a p t e r s  f o r  e a c h  o f  t h e s e  l a n d  u s e  p e r m i t s  
r e f e r e n c e s  c o m p l i a n c e  w i t h  a l l  a p p l i c a b l e  
d e v e l o p m e n t  s t a n d a r d s ,  w h i c h  i n c l u d e s  t h e  t r e e  
c a n o p y  c o v e r  s t a n d a r d s  i n  C h a p t e r  1 8 . 7 9 0 .  
T h i s  c o n t i n u e s  c u r r e n t  a d m i n i s t r a t i o n  r e g a r d i n g  
t h e  a p p l i c a b i l i t y  o f  t h e  s t a n d a r d s  i n  C h a p t e r  
1 8 . 7 9 0 .  A s  r e q u e s t e d  p r e v i o u s l y  b y  t h e  C i t i z e n  
A d v i s o r y  C o m m i t t e e ,  t h e  C i t y  A t t o r n e y  h a s  
r e v i e w e d  a n d  a p p r o v e d  t h i s  r e s p o n s e .  
C O D E  
S E C T I O N  
1 8 . 7 9 0 . 0 2 0  
C o d e  
# COMMENTER SUMMARIZED COMMENT STAFF UPDATE/RESPONSE CODE 
(DATE) SECTION 
St across Fanno Creek, the 
hearings o fficer ruled that an 
owner's signature, required on the 
Land Use Application (an 
applicable and required city form) 
was an 'application standard' , not 
an approval criterion, therefore 
didn't need to be met. 
13. J ohn Frewing The definition of 'drip line' should N o revisions were made based on this 8.02.030 and 
(12-12-2011) make clear that we are talking comment. The definition of dripline addresses 18.120.030 
about a vertical drop from the the comment: Code 
outside of the crown; it elsewhere 
in the code talks about an area "Dripline" - The outer limit o f a tree canopy 
'covered' by the crown. See projected to the ground. 
8.02.030Y. 
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J o h n  F r e w i n g  
T h e  c i t y  s h o u l d  r e q u i r e  a  T y p e  I I  
( 1 2 - 1 2 - 2 0 1 1 )  a p p r o v a l  p r o c e s s  f o r  s i g n i f i c a n t  
c h a n g e s  t o  a n  U r b a n  F o r e s t  P l a n  
o n c e  i t  i s  a p p r o v e d .  " S i g n i f i c a n t "  
c h a n g e s  w o u l d  i n c l u d e  m o d i f y i n g  
m o r e  t h a n  2 5 %  o f  t h e  r e q u i r e d  
t r e e s  t o  b e  p l a n t e d  o r  p r e s e r v e d  o n  
a  l o t  .  
S T A F F  U P D A T E / R E S P O N S E  C O D E  
S E C T I O N  
N o  r e v i s i o n s  w e r e  m a d e  b a s e d  o n  t h i s  1 8 . 7 9 0 . 0 7 0  
c o m m e n t .  T h e  C i t i z e n  A d v i s o r y  C o m m i t t e e  C o d e  
s p e c i f i c a l l y  a d d r e s s e d  t h e  U r b a n  F o r e s t r y  P l a n  
m o d i f i c a t i o n  i s s u e  i n  i t s  g u i d i n g  p r i n c i p l e s .  
G u i d i n g  p r i n c i p l e  1 0  f o r  t h e  u r b a n  f o r e s t r y  
s t a n d a r d s  f o r  d e v e l o p m e n t  s t a t e s :  
" A l l o w  m o d i f i c a t i o n s  o f  a n  u r b a n  f o r e s t r y  p l a n  
d u r i n g  t h e  c o u r s e  o f  d e v e l o p m e n t  t h r o u g h  a  
T y p e  I  r e v i e w  p r o c e s s  s o  t h a t  p l a n t i n g  a n d  
p r e s e r v a t i o n  s t r a t e g i e s  c a n  b e  e a s i l y  a d a p t e d . "  
T h e  C i t i z e n  A d v i s o r y  C o m m i t t e e  i n i t i a l l y  
c o n s i d e r e d  a  T y p e  I I  p r o c e s s  f o r  s i g n i f i c a n t  
m o d i f i c a t i o n s  t o  a n  U r b a n  F o r e s t r y  P l a n ,  b u t  
r e a c h e d  c o n s e n s u s  o n  a  T y p e  I  p r o c e s s .  T h e  
r a t i o n a l e  o f  t h e  C i t i z e n  A d v i s o r y  C o m m i t t e e  
w a s  t h a t  i f  t h e  m o d i f i c a t i o n  p r o c e s s  i s  l e s s  
b u r d e n s o m e ,  p e o p l e  w o u l d  b e  m o r e  w i l l i n g  t o  
" t a k e  a  c h a n c e "  o n  p r e s e r v a t i o n  k n o w i n g  t h e y  
w o u l d  h a v e  t h e  f l e x i b i l i t y  f o r  r e m o v a l  a s  t h e  
d e v e l o p m e n t  p r o c e s s  p r o g r e s s e s .  T h i s  c o u l d  
r e s u l t  i n  a d d i t i o n a l  pres~rva tion .  
# COMMENTER SUMMARIZED COMMEN T STAFF U PDATE/RESPONSE CODE 
(DATE) SECTION 
15. John Frewing TDC 18.790.060 makes reference This has been incorporated into the draft 18.790.060 
(12-12-2011) to 'final acceptance by the Urban Forestry Code Revisions. For Code 
Director'. Under what process or clarification as to when an urban forestry plan 
inspection does the Director make is no longer in effect, the term " final 
such 'final acceptance' and how is acceptance" has been replaced with " the 
it documented? director determines all applicable urban forestry 
plan conditions of approval and code 
requirements have been met" in section 
18.790.060.A. This is determined following a 
city inspection and will be documented in the 
city's permit tracking system (as is current 
practice). 
16. John F rewing The UFM calculation of effective No revisions were made based on this Urban 
(12-12-2011) canopy has some problems with it: comment. Forestry 
1. No coverage of the public 1. Throughout the Urban Forestry Code Manual 
right of way (sidewalk, Revisions process, the canopy cover Section 10 
planter strip, street) is standards were applied based on the 
required, yet credit is given overall development site area, excluding 
to the lot for canopy cover streets . Staff and outside consultants 
over these areas. If canopy tes ted the canopy cover standards based 
over paved areas is desired, on this method and determined they 
it should be required in result in a reasonable amount of 
some amount; I suggest planting and preservation. The Citizen 
that at maturity, 20 percent and Technical Advisory Committees 
of the right of way should also reviewed the results of applying the 
be under a tree canopy. canopy cover standards based on this 
This distortion of the method and the general consensus was 
standards is shown most the results were reasonable. Staff does 
clearly on the E dgewood not recommend modifying the canopy 
example, where I think cover calculations without significant 
NO trees are required in technical and public review of the 
the back yards on the west implications. 
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s i d e  o f  t h e  d e v e l o p m e n t  - -
i t  i s  e x a c t l y  t h i s  l o c a t i o n  
w h e r e  t r e e s  w o u l d  
c o n t r i b u t e  t o  b u f f e r i n g  a n d  
s h a d i n g  d u r i n g  t h e  
s u m m e r .  
2 .  C r e d i t  f o r  c a n o p y  c o v e r  
s e e m s  t o  b e  g r a n t e d  f o r  
s i t u a t i o n s  w h e r e  t r e e  
g r o w t h  i s  l i m i t e d  b y  p o w e r  
l i n e s  o r  b y  i n t e r f e r e n c e  
w i t h  b u i l d i n g  s t r u c t u r e  - -
s e e  t h e  e x a m p l e  o f  h o u s i n g  
a t  I - : I a l l / I - : I u n z i k e r  S t .  
P l e a s e  e x p l a i n  h o w  t h e s e  
s i t u a t i o n s  c o u l d  b e  f i x e d .  
S T A F F  U P D A T E / R E S P O N S E  
C O D E  
S E C T I O N  
T h e  d r a f t  c o d e  w i l l  l i k e l y  r e s u l t  i n  
s i g n i f i c a n t  t r e e  c a n o p y  o v e r  s t r e e t s .  
S t r e e t  t r e e s  a r e  r e q u i r e d  b a s e d  o n  t h e  
a m o u n t  o f  s t r e e t  f r o n t a g e  f o r  t h e  
d e v e l o p m e n t  T h e r e  i s  a n  i n c e n t i v e  t o  
m a x i m i z e  s t r e e t  t r e e  c a n o p y  b e c a u s e  
f u l l  c r e d i t  i s  g r a n t e d  e v e n  t h o u g h  h a l f  
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o n  s t a f f  a n d  o u t s i d e  c o n s u l t a n t  t e s t i n g ,  
t h e s e  i n c e n t i v e s  r e s u l t  i n  a  s h i f t  o f  
c a n o p y  o v e r  s t r e e t s .  
T h e  C i t i z e n  A d v i s o r y  C o m m i t t e e  w a s  
g e n e r a l l y  s u p p o r t i v e  o f  s h i f t i n g  c a n o p y  
f r o m  b a c k y a r d s  t o  s t r e e t s  s i n c e  s t r e e t  
t r e e s  h a v e  h i g h  b e n e f i t  t o  c o s t  r a t i o s ,  
s t r e e t  t r e e s  a r e  e a s i e r  f o r  t h e  c i t y  t o  
m o n i t o r  i n  t h e  y e a r s  a f t e r  d e v e l o p m e n t ,  
a n d  m o r e  f l e x i b i l i t y  i n  b a c k y a r d  
l a n d s c a p i n g  ( a s  o p p o s e d  t o  p r o t e c t e d  
t r e e s )  w a s  v i e w e d  a s  p o s i t i v e .  
A l s o ,  t h e r e  a r e  e q u i t y  i s s u e s  w i t h  
r e q u i r i n g  c e r t a i n  p e r c e n t a g e s  o f  t r e e  
c a n o p y  o v e r  t h e  r i g h t  o f  w a y .  T h i s  i s  
b e c a u s e  o f  t h e  v a r i o u s  w i d t h s  o f  s t r e e t s .  
F o r  e x a m p l e ,  i t  w o u l d  b e  e a s i e r  m e e t  
p e r c e n t  c a n o p y  r e q u i r e m e n t s  f o r  
d e v e l o p m e n t s  f r o n t i n g  l o c a l  s t r e e t s  t h a n  
d e v e l o p m e n t s  f r o n t i n g  a r t e r i a l s .  
2 .  
( T h i s  i s  a d d r e s s e d  i n  r e s p o n s e  t o  p u b l i c  
c o m m e n t  5 )  
# COMMENTER SUMMARIZED COMMEN T STAFF UPDATE/RESPONSE CODE 
{DATE) SECTION 
17. John Frewing How does the proposed code deal No revisions were made based on this Urban 
(12-12-2011) with the situation where an comment. For exis ting open grown trees, Forestry 
exis ting tree is somewhat skewed, Section 10, Part 3 o f the Urban Forestry Manual 
so that its canopy is no t a perfect Manual grants credit as follows: Section 10 
circle? When discussing trees to 
be planted and mature later, a (average tree canopy spread / 2)2 x n 
perfect circle of canopy is 
assumed. How will canopy be Averaging the canopy spread accounts for 
evaluated if such a circle does not asymmetrical canopy growth of exis ting trees. 
grow? For an existing tree, is 
canopy measured with the exis ting 
shape of crown or is some other 
method of measurement used? 
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T h e  r a i s e d  c o d e  s h o u l d  a d d r e s s  
( 1 2 - 1 2 - 2 0 1 1 )  ' r e d e v e l o p m e n t '  o n  a  l o t .  P o r t l a n d  
r e q u i r e s  t h a t  i f  a  r e d e v e l o p m e n t  
e x c e e d s  a  c e r t a i n  c o s t ,  s t r e e t  t r e e s  
a r e  r e q u i r e d ,  a n d  i f  r e d e v e l o p m e n t  
a d d s  a  c e r t a i n  a r e a  t o  a  b u i l d i n g ,  a  
t r e e  p l a n  i s  r e q u i r e d .  T i g a r d  
s h o u l d  i n c l u d e  s u c h  p r o v i s i o n s .  
S T A F F  U P D A T E / R E S P O N S E  
C O D E  
S E C T I O N  
N o  r e v i s i o n s  w e r e  m a d e  b a s e d  o n  t h i s  1 8 . 3 3 0  
c o m m e n t .  T h e  d r a f t  c o d e  a d d r e s s e s  t h e  1 8 . 3 5 0  
r e d e v e l o p m e n t  o f  c o m m e r c i a l ,  i n d u s t r i a l  a n d  
1 8 . 3 6 0  
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1 8 . 4 2 0  
t h a n  h a l f  t h e  t r e e  c a n o p y  o f  r e s i d e n t i a l  z o n e s .  1 8 . 4 3 0  
T h e  g e n e r a l  c o n s e n s u s  o f  t h e  C i t i z e n  A d v i s o r y  1 8 . 6 1 0  
C o m m i t t e e  w a s  t o  n o t  r e q u i r e  a d d i t i o n a l  t r e e s  i n  1 8 . 7 7 5  
r e s i d e n t i a l  z o n e s  f o r  r e d e v e l o p m e n t  ( e . g .  b u i l d i n g  C o d e  
a d d i t i o n s ,  r e m o d e l i n g ,  e t c . )  b e c a u s e  p e o p l e  w i l l  
p l a n t  t r e e s  t h e r e  v o l u n t a r i l y  w i t h o u t  r e g u l a t i o n s .  
T h e  t h r e s h o l d  f o r  a p p l i c a t i o n  o f  t h e  u r b a n  
f o r e s t r y  s t a n d a r d s  a r e  d e t a i l e d  i n  t h e  
c o r r e s p o n d i n g  c h a p t e r s  f o r  t h e  T y p e  I I  a n d  I I I  
l a n d  u s e  p e r m i t s  t h a t  a r e  r e q u i r e d  t o  p r o v i d e  
U r b a n  F o r e s t r y  P l a n s  ( C U P ,  D D R ,  M L P ,  P D ,  
S L R ,  S D R ,  a n d  S U B ) .  T h e  r e d e v e l o p m e n t  
t h r e s h o l d s  a r e  b a s e d  o n  t h e  a m o u n t  o f  
m o d i f i c a t i o n  t o  b u i l d i n g s  o r  s i t e s ,  r a t h e r  t h a n  
c o s t .  
Urban Forestry Code Revisions 
CAC Guiding Principles 
City of Tigard Urban l;orcst:ry Code ReYisions I Volume \' I 139 

Guiding Principles 
BACKGROUND 
D eveloped over two years from February 2010 to the spring o f 2012, the Urban Forestry Code 
Revisions project reflects Tigard City Council's direction for a comprehensive urban forestry code 
update with enhanced public involvement. Recognizing from previous efforts that issues pertaining 
to trees can be particularly polarizing, council chose this direction to maximize the potential for 
reaching consensus. 
In September 2011 , the Citizens Advis01y Committee (CAC) completed their work by reaching 
consensus on the outcom es reflected in the proposed code. T he CAC reached a consensus vote on 
each topic area through a set o f "guiding principles." T he intent o f the principles is to summarize the 
committee's discussions on each topic and serve as a guide during the adoption process. T he 
principles concisely convey the main elements o f each topic area and represent a compromise 
between the diverse interes ts and viewpoints of the CAC members. T hese principles were voted on 
by topic during a comprehensive review o f the code held in August and September 2011 . 
Urban Forestry Standards for Development 
D evelopment projects build, improve and maintain public and private infras tructure including 
streets and utilities in accordance with city standards. D evelopment projects shall also contribute to 
the urban fores t component o f the city's green infras tructure regardless of existing site conditions as 
follows: 
Application 
1. Provide an urban foresuy plan by a certified arborist outlining m ethods for preserving, 
planting and maintaining trees in accordance with industry accepted standards. 
2. Meet tiered "effective canopy" targets (25 - 40 percent) tailored by zone with: 
• N ew trees that have adequate soil resources, appropriate species, a diverse mix and 
are well placed; or 
• Existing trees in good condition, suitable for preservation, appropriate species and 
are well protected during development. 
3. Require street trees and parking lo t trees to meet detailed soil volume standards. These trees 
o ften have limited access to soil needed to support their function of providing canopy over 
impervious surfaces. 
4. E ncourage planting of new trees that will be large stature at maturity to meet tiered canopy 
targets. Well placed, large stature trees are proven to have high benefit to cost ratios. 
City of Tigard Urban Forestry Code Rc,·isions I Volume V I 141 
Implementation 
5. Require regular monitoring and reporting of an urban fores try plan during the course o f 
development by a certified arborist to ensure successful implementation . 
6. Record spatial and species specific data for inclusion in a publicly accessible inventory o f 
trees. Readily accessible information on protected trees benefits citizens and the city when 
malting future decisions in the years following development. 
Preservation Incentives and Flexible Standards 
7. Grant bonus credits toward tiered canopy targets as an incentive for tree preservation. 
8. Allow a fee in lieu of meeting tiered canopy requirements to be used for a designated range 
of activities that support the Urban Fores try Master Plan. 
9. To provide greater flexibility in meeting canopy requirements, allow a discretionary review 
track. T his is in lieu of meeting tiered canopy requirements or fees for incorporating 
innovative, alternate development proposals that provide equivalent environmental benefits 
as trees (energy, hydrology, solar, wildlife, etc .). 
10. Allow modifications of an urban fores try plan during the course of development through a 
Type I review process so that planting and preservation strategies can be easily adapted. 
11 . Provide flexibility in sidewalk, parking, landscape and lot standards to facilitate preservation 
and planting. 
U rban Forestry Standards for Development Guiding Principles 
'1 mppori these principks bo.std upon thet,roup i ermmum at the .Anl!'st 10, 2011 mtdilt,. u 
Too-r T-rcn 
Scott Berohud 
Dand Walsh 
Donald Schmidt 
BtttLetWleo 
Ken~= 
BriaoW~., 
ohn \\>land 
Ci ty o f Tigard Urban l'orc•stry Code Rc,-isions I \ 'olumc \ ' I 142 
Tree Grove Preservation Incentives 
Within the city limits, 70 native tree groves covering 544 acres have been identified as significant 
through the state Goal S rule requirements. D evelopment projects with a mapped significant tree 
grove shall be eligible for flexible standards and incentives to aid in preserving the grove. To be 
eligible, groves shall be a minimum size with a significant percentage preserved. 
Allowed D ensity 
1. Allow reduction of minimum residential density requirements based on the amount of grove 
preserved. As more grove is preserved, require fewer units. 
2. Allow transfer of residential density from the grove to the non-grove portion of a site. As 
more grove is preserved, allow a reduction in required setbacks, lot and unit dimensions. 
3. Allow additional building height and reduced setbacks for commercial and industrial 
development that preserves a grove. 
N eighborhood Compatibility 
4. E nsure compatibility with the surrounding neighborhood when transferring density for 
grove preservation. 
5. Maintain adequate buffering and screening from surrounding development when adding 
height and reducing setbacks for commercial and industrial development that preserves a 
grove. 
T ree Grove Health 
6. Waive any lot-by-lot canopy standard in favor of preserving cohesive canopy from a grove. 
7. Establish authority to adjust street, sidewalk, parking and utility standards in favor of 
preserving a grove as long as it does not create an unreasonable risk to the public. 
8. Require the applicant to work with a certified arborist to maximize the connectivity and 
viability of the preserved portion of a grove in accordance with industry accepted standards. 
9. Require permanent protection of a grove within a development that utilizes any of the 
flexible standards and incentives for grove preservation. 
City of Tigard Urban Forestry Code Re,-isions I Volume V I 143 
Tree Grove Preservation Incentives Guiding Principles 
'1 mpporl then priMipks bomi upon lbt ur>"P s mnJtlf.rus allbt hSJISI 10, 2011 mttlin.g. " 
Signed bv -
Ton\ TT'Cer 
Scon ~mhard 
Dand \\alsh 
Donald Schmidt 
B<etL.,WJeo 
John F<· 
Kn1 G~ttt 
Brim\\~gme~e 
ohn \\ylaod 
Tree Permit Requirements 
Tree permit requirements shall es tablish clear and consistent standards for permitting the planting, 
removal and replacement o f trees to ensure a healthy and sustainable urban fores t. 
T he tree permit requirements shall not regulate any more tree situations than the city currently does, 
but rather improve the consistency, clarity and scientific basis for decision-making. 
Code Structure 
1. Consolidate tree permit requirements into a single title for ease o f use by citizens and 
decision-makers. 
2. Continue to require tree permits for the following categories of trees: 
• Street and median trees; 
• T rees in sensitive lands; 
• T rees that were required with development; 
• Trees that were planted using the Urban Fores try Fund; and 
• Heritage Trees. 
Cit-y o fTiganJ Urban l'orc>try Code RtYi>iom I \'olumc \ ' I 144 
D ecision-Making 
3. Provide two tracks of decision-making for tree permits: 
• A low- or no-fee administrative review process by city staff for simple situations 
such as trees that are in poor or hazardous condition, nuisance trees, causing 
damage, fire dangers or preventing allowed development to occur (except H eritage 
Trees) . D o not allow removal of H eritage Trees for development through an 
administrative process since H eritage Trees are designated through a public process. 
• A public review process by a designated board or commission for more complex 
situations where the reasons for removal are less clear. T he designated board or 
commission shall be authorized to use their discretion to weigh the tree benefits and 
reasons for rem oval when making their decision. 
Publicly Recognizing Trees 
4. Provide two tracks for publicly recognizing unique trees in the community: 
• H eritage trees shall be o f landmark importance, afforded regulatory protection from 
rem oval and eligible for city funding for maintenance. 
• Significant trees shall also be o f landmark importance, but not afforded regulatory 
protection from rem oval, and not eligible for city funding for maintenance. The 
significant tree track allows property owners to publicly recognize their trees without 
losing flexibility for tree rem oval on their property. 
E nforcem ent 
5. Establish enforcement provisions that deter violations while protecting citizens from 
disproportionate penalties for tree rem oval violations. 
City of Tigard Urban Forestry Code Re,·isions I Volume V I 145 
Tree Permit Requirements Guiding Principles 
'1 .mpport thest printipks based upon thelf'Oup'.u:on.rensu.r at the Septtmber 14, 201 1 meeting." 
SIJ~r·i t,·· 
l\Iorl!"all Holen 
Donald Schmrot 
Ken_l:;ea:z 
Brian \\ e~Z"enl"l: 
Scott Bemhud 
D a't'id Walsh 
lohn Wriand 
]i>lul Fre~ -- · ~~~--r-------
~ Bret L euallen "'Tony Tycer mo"t"ecl 
H azard Trees 
While the urban fores t provides economic and environmental benefits for the conununity, proper 
management is essential for maximizing these benefits. When managing the urban fores t, safety shall 
be of primary importance, and clear code standards and procedures for addressing hazard trees 
creates the regulatory framework for minimizing tree risk. 
Purpose 
1. Clearly define what constitutes a hazard tree using the standardized tree risk assessm ent 
methodology developed by the International Society o f Arboriculture. T his methodology 
factors in the probability o f failure, the target area and the size o f defective part when 
evaluating risk. 
2. Requite hazard tree abatement when the risk rating exceeds a defined threshold. Abatem ent 
may be achieved through pruning, tree removal or o ther means in accordance with 
applicable rules and regulations. 
Process 
3. Establish a process fo r people (including groups) to resolve hazard tree issues in an 
objective, equitable and efficient manner. T he process shall be structured to limit false or 
frivolous claims and incentivize people to work out issues informally without formal city 
involvement. 
City or T iganJ Urban l'orc"n· Code Rc,·isiom I \ 'olume \ ' I 1-16 
4. Require people to demonstrate they have standing before filing a formal hazard tree claim. A 
person shall have standing if they can demonstrate their life, limb or property has the 
po tential to be impacted by the alleged hazard tree, and they have tried unsuccessfully to 
work the issue out informally. 
5. Utilize third-par ty tree risk assessors when independent hazard tree decisions through the 
formal city process are warranted. Use o f third-party tree risk assessors will help limit the 
city's liability. 
6. G rant the city authority to gain access to proper ty for hazard tree abatement to enforce code 
provisions or in case of emergency. 
Cost Recovery 
7. Recover costs incurred by the city when parties rely on the formal city process for resolving 
hazard tree issues. T he public should no t have to bear the full cost for issues that should be 
resolved without city involvem ent. 
Hazard Trees Guiding Principles 
'1 mppotf thue principles bam/ 1ljX»t thetpmp's l'flllmiSIIS aJ lhtSeptemlxr 14, 2011 medin.g. " 
SiJ.,..b< 
(/ '-'f / ()- Moqzan Holen . 'Yt' """>~ {·~ ...... 
__Donald Sclunidt 
'= - :;;:::, Ken Gatz 
Brian Wel!e!leL 
Scott Bemhud 
John Ft~--
David Walsh 
BLetLieuallen 
*Tony Tycet: moved 
City of 'J'igard Urban Forestry Code Re,·isions I Volume V I 147 

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To: 
From: 
Re: 
D ate: 
City of Tigard 
Memorandum 
City Council 
John Floyd 
Urban Forestry Annotated Bibliography 
November 16, 2011 
Community D evelopment staff has assembled the attached bibliography to document the diverse range 
of benefits and services provided by a healthy urban fores t. These benefits and services include 
environmental, economic, social, and aesthetic contributions. Where the authors have made abstracts of 
their works available, these existing abstracts are included and are denoted by an as terisk (*). For each 
of the other works, staff has composed an abstract. 
A ttachment: 
.Annotated Bibliography 
City of Tigard Urban Fores try Code Re,·isions I Volume \' I 151 

Annotated Bibliography 
Center for Urban Forest Research. (2003). Is All Your Rain Going Down the Drain? USDA Forest 
Service, Pacific Southwest Research Station. 4 p. 
Urban trees mn be a signijicant asset for the reduction of stormwater t7tno.ff ry retaining rainwater and slowing 
soil erosion. An urban forest of 10,000 trees will reduce runoff ry 10 million gallons or more of water each year. 
Large-crmvned trees which are in-/eqf coim"iding with the most prec-ipitous season, or are evergreens, provide the 
greatest benr:fit. 
Center for Urban Forest Research. (2006) . W0t Shade Streets? The Unexpected Benr:fit. USDA Forest 
Service, Pacific Southwest Research Station. 4 p. 
This report presents research on the benr:fits of street trees for road maintenance in California's Centra/ Vallry. 
EtJaporation at high temperatures of the binder in asphalt increases the instance of /m;ge cracks in pmJement otJer 
time. Streets that are shaded ry trees are less susceptible to this effect and require less frequent maintenance. 
Shading streets can satJe be!Jveen 17% (1vhen small trees are used) and 58% (when large trees are used) on 
resuifaang and repair costs versus un-shaded streets. EffectitJeneJS is highest when large, deep-rooted trees are 
se/eded, adequate soil volume is maintained, and trees are placed at /east three feet from arry pavement. 
Donovan, G.H., & Butry, D . (2010). "Trees in the City: Valuing Street Trees in Portland, Oregon." 
Landscape and Urban Planning 94(2), 77-83. 
*Donovan and Butry use a hedonic price mode/ to simu/taneous!J estimate the effects of street trees on the sales 
price and the time-on-market (TOM) of houses in Port/and, Oregon. On average, street trees add $8,870 to sales 
price and reduce TOM ry 1. 7 days. In addition, the authors found that the benr:fits of street trees spill over to 
neighboring houses. Because the provision and maintenance of street trees in Port/and is the responsibility of 
acfjacent property owners, their results suggest that if the provision of street trees is lift sole!J to homeowners, then 
there will be too jew street trees from a soaeta/ pmpective. 
D onovan, G.H., Michael, Y.L., Butry, D .T., Sullivan, A.D., & Chase,J.M. (2010) . "Urban Trees and 
the risk of poor birth outcomes." Health and Place. 17:390-393. 4p. 
*This paper investigated whether greater tree-canopy cover is assoc-iated with reduced risk of poor birth outcomes in 
Port/and, Oregon. Residential addresses were geocoded and /inked to dassijied-aeria/ imagery to calculate tree-
canopy cotJer in 50, 100, and 200 m btiffers around each home in the sample (n=5696). Detailed data on 
materna/ characteristics and additional neighborhood variables were obtained from birth certijicates and tax 
records. The stutjy found that a 10% increase in tree-canopy cover within 50 m of a house reduced the number of 
sma/1 for gestational age births ry 1.42 per 1000 births (95% CI-0. 11 -2.72). Results suggest that the natura/ 
environment may ciflect pregnanry outcomes and should be evaluated in future research. 
White, Rachel E., Geoffrey H . D onovan, Jeffrey P. Prestemon. 201 1. Trees thwart shady behavior. 
Nursery Management and Production. February: 30-33. 4p. 
This stutfy measured trees at 2,813 sing/efamzjy homes in Port/and, Oregon and compared this information 1vith 
data on crime occurrences. Controls 1vere used for variable sudJ as market value, OTJerall appearance, and TJisua/ 
barriers such as Jvalls and fem-es, crime preTJention measures, and proximity to commerc-ia/ areas and bu.ry streets. 
3 
City o f Tigard Urban Forestry Code Re,·isions I Volume V I 153 
Tbe .rtuqy found tbat bou.re.rji·on!ed 1vitb more .rtreet tree.r and larger yard tree.r bad lower crime rate.r. Tbi.r 
included both total crime rate.r and .specijicproperty crime.r JlldJ a.r tJanda!iJm and burglary. 
D onovan, Geoffrey H., D avid Butry. 2011 . The effect of urban trees on the rental price of single-
family homes in Portland, O regon. Urban Fomtry and Urban Greening. 1 0(3):163-168. 6p. 
*Fe1v .rtudie.r bave e.rlimated the ifled of environmental amenitie.r on tbe rental price of bou.re.r. Tbe .rtuqy trie.r to 
addrm tbi.r gap in tbe literature I?J quantijjing tbe ifled of urban tree.r on tbe rental price of JingleJamzjy home.r 
in Portland, Oregon. Tbe .rtuqy found that an additional tree on a bou.re '.r lot increaJed montb!J rent I?J $5.62, 
and a tree in tbe public rigbt of1vqy increa.red rent I?J $2 1.00. Tbe.re remlt.r are comi.rtent 1vith a previou.r 
hedonic ana!J.ri.r of tbe iffect.r of lree.r on the .rale price.r of bome.r in Portland, which .rugge.rt.r that home01vner.r and 
renter.r place .rimilar tJalue.r on urban tree.r. 
Geiger, Jim. (2004). The Large Tree Argument: Tbe Ca.re for L m:ge Tree.r v.r. Small Tree.r. Center for Urban 
Forest Research, USDA Forest Service, Southern Center for Urban Forestry Research & 
Information. 8p. 
Planting and maintaining a.r mmry lm:ge-.rtature tree.r a.r po.r.rible i.r economicai!J and em;ironmentai!J preferable 
over the long run to planting and maintaining .rmall-.rtature tree.r. The article cite.r a compari.ron .rtuqy of co.rt.r and 
beneftt.r for d!iferentplan.r for mtmi{ipal tree planting and maintenance and provide.r .rugge.rtiomfor marketing 
lm:ge-.rtature tree.r to (YJmmunitie.r. 
McPherson, E .G ., Maca, S.E., Simpson, JR. , Peper, P.J., Xiao, Q., VanDerZanden, A.M., & Bell, N. 
(2002). IVe.rtern J,f/a.rhington and Oregon Community Tree Guide: Beneftt.r, Co.rtJ and Strategic Planting. 
Center for Urban Forest Research, USDA Forest Service, Pacific Southwest Research Station, 
pp. 5-12, 17-22. 
*Deti.rion.r about im;e.rtment.r in commtmity tree.r depend on correct!J calculating the co.rt.r and ben~jit.r of planting 
and maintaining tree.r in commum!J .space.r:yardJ~ park.r, and .rtreet location.r, The Tree Guide de.rcribe.r .rtudie.r 
calmlating tbe e('()nomic beneftt.r qf tree.r to energy con.ren;ation, air cooling, pollutant and nmoffreduction, .rtreet 
.rbading, and land tJalue, a.r well a.r .rtudie.r calculating the co.rt.r of planting, pnming, and removing tree.r, 
irrigation, pe.rt and di.rea.re (YJntrol, i1ifra.rtmcture repair, cleanup, liability, and admini.rtration. Net beneftt.r or 
(YJJt.r are calculated I?J Jveighing the beneftt.r verm.r ('()Jt.r at four different .rcale.r-parcel, neigbborhood, community, 
and globat-then .rumming the re.rult.r. The .rummed re.rult.r rel!ealnet beneftt.r exceeding net co.rt.rfor all large 
tree.r, all medium re.ridential tree.r, and all .rmall tree.r oppo.rite we.rtJacing wall.r. 
McPherson, E . G., & Muchnick, ]. (2005). "Effects of Street Tree Shade on Asphalt Concrete 
Pavement Performance." Arboriculture & Urban f<omtry 3 1 (6), 303-310. 
*F'orty-eigbt .rtreel .regment.r 1vere paired into 24 high and low-.rbade pair.r in Mode.rto, California. Field data were 
('()/leded to calm/ate a Pm;ement Condition Index (PC!) and Tree Shade Index (JSJ) for eacb .regment. 
S tati.rtical ana!Jm·found that greater PC! JvaJ a.r.rociated with greater TSI, indicating tbat tree .rbade JVaJ 
partiai!J mpon.rible for reduced pm;ement fatigue cracking, rutting, .rbol!ing, and other diJtre.r.r. UJing ob.ren;ed 
relation.r between PCJ and TSJ, an 1111-Jhaded .rtreel .regment required 6 .rlurry .real.r ol!er 30 yean, Jvhile an 
identical one planted 1vz'tb 12 {Tape nryrtle.r {L.Llger.rtroemia indica, 4.4 m [14 ft.] cr01vn diameter) required 5 
.rlurry .real.r, and one 1vitb 6 Cbine.re hackberry (Celti.r .rinemi.r, 13.7 m [45ft.] {TOJvn diameter) required 2.5 
4 
City of' Tigard Urban Jiorc,try Code Rc,,i,iom I \ 'olumc \ ' I 154 
slurry seals. Shade from the large hade berries 1vas prqjected to save $7. 13 I m2 ($0.66 I ft2) over the 30-year 
period compared to the un-shaded street. 
McPherson, E .G ., Simpson, J R., Peper, P.J ., Maco, S.E., & Xiao, Q .(2005). "Municipal Forest 
Benefits and Costs in Five US Cities." Journal ofForestry, 103(8), 411 -41 6. 
*Increasingly, ci!J trees are viewed as a best management practice to control stormwater, an urban-heat-island 
mitigation measure for deaner air, a C02-reduction option to offset emissions, and an alternative to cost!J new 
elutric power plants. Measuring benljits that accrue from the communi!J forest is the first step to alteringforest 
strudure in wqys that will enhance future benljits. This artide descn"bes the structure, function, and value of street 
and park tree populations in rort Collins, Colorado; Chryenne, l~oming; Bisman·k, North Dakota; Berkelry, 
California; and Glendale, Arizona. Although these cities spent $ 13-$65 annuai!J per tree, benljits ranged from 
$3 1 to $89 per tree. For every dollar invested in management, benljits returned annuai!J ranged from $ 1.3 7 to 
$3.09. Strategies each ci!J can take to increase net benljits are presented. 
Nowak, David J. The Effects of Urban Trees on Air Quali!J. USDA Forest Service, Northeastern 
Research Station. 4p. 
Urban vegetation direct!J and indirect!J alters local and regional air quali!J in Jour principal wqys. Urban 
tJegetation can reduce air temperature and ifled other changes in local meteorology. Trees remove pollutants from 
the atmosphere both temporari!J ry intercepting airborne particles and permanent!J through leaf uptake. Trees 
emit tJolatile organic compounds (VOCs) and mqy result in the emission of additional VOCs from tree 
maintenance, yet can reduce overall VOC emissions ry lowering air temperatures and absorbing evaporative 
emissions. Appropriate!J placed, mature trees reduce building energy use, while improper!J sited trees mqy increase 
building energy use. The combined iflects suggest that urban forest management strategies should promote planting 
and sustaining large, long-lived, and low-maintenance trees in energy-conserving and pollution-reducing locations. 
Sullivan, W.C., Kuo, F.E., & D ePooter, S.F. (2004). "The Fruit of Urban Nature: Vital 
Neighborhood Spaces." Environment and Behavior 36(5) 678-700. 
*What makes a neighborhood space vital? This artide e:>..plores the possibiliry that the presence of trees and grass 
mqy be one of the kry components of vita/neighborhood spaces. The authors report on 7 58 observations of 
individuals in 59 outdoor common spam in a residential development. Twenry-seven of the neighborhood common 
spaces were relative!J green, whereas 32 1vere relative!J barren. Results indicate that the presence of trees and grass 
is related to the use of outdoor spaces, the amount of social activi!J that takes place within them, and the 
proportion of social to nonsocial activities thry support. The findings improve and broaden our understanding of 
the pf?Jsical characteristics that influence social contact among neighbors and provide evidente that nature plqys an 
important role in creating vita/neighborhood spaces. 
Wolf, Kathleen L. (2007). "City Trees and Property Values." Arborist Ne1vs 16(4), 34-36. 
All forms of urban nature-parks, greenbelts, open space, street trees, ett.- are pub/it goods whith provide a 
range of benljits and ser!Jites to socie!J. For poliry and investment decisions, whether pub lit or priwte, mmomit 
valuation is paramount. Etonomic decision-making tentered on produttive use and hard tost can obsture incentitJes 
to invest in urban nature. The benljits of urban nature tan be represented economicai!J using hedonit pricing and 
nonmarket valuation. U tilii}1tg these methods can yield evidente in favor of im;estment in urban nature ry 
reveali1tg non-excludable benljits for all members 1vitbin a tammuni!J and added value to properties with trees. 
5 
City o f Tigard Urban Forestry Code Re,·isions I Volume V I 155 
Wolf, Kathleen L. (2005). "Civic Nature Valuation: Assessments of H uman Functioning and Well-
Being in Cities." ForgingS olutiom: App!Jing Ecological Emnomic.r to Curren/ Problem.r, Proceeding.r qftbe 
3"1 Biennial Conference of !be U.S. Society for Ecological Economic.r. Tacoma, W A: Earth Economics . 6p. 
*Ci1Jic nature i.r !be mllec!it;e "con.rtmcted nature" if citie.r and can include park.r, open .rpace.r and urban fomi.r, 
on public or prit;a/e land.r. The exi.rlence and qualiry if r:it;ic nature i.r dependent 011 compreiJen.rit;e planning and 
management. Ci1Jic nature adt;ocate.r are called upon to jliJt~(y !be public co.rl.r of amem/ie.r !IJa! are often perceit;ed 
a.r baiJing on!J ae.r!betic tJa!ue. Urban nature protJide.r multiple valuable .ren;ice.r, and economic 1Jaluation qf.mcb 
.reriJice.r ba.r been initiated. Valuation of the buman .ren;ice.r prot;ided ~urban tree.r and open .rpace - pby.rical 
beal!b, mental health and flmctioning, community bealtb and .rafery - i.r another opportunity for re.rearcb and 
dialog about natttre-ba.red public good.r. 
Wolf, Kathleen L. (1998). /-Iuman Dimemion.r qf tbe Urban Fore.rl, Fad Sheet 1 - Urban Nature Benifit.r: 
P-!Jcbo-Sodal Dimemiom oj"People and Plant.r. Center for Urban Horticulture, University of 
Washington, College of Fores t Resources . 2p. 
Urban tree.r are aJJor:ialed Jvilb vmiou.r po.ritit;e if!ect.r on e11eryday mood.r, acti11itie.r, and emotional bealtb. 
E>..po.rure lo nature belp.r lt.f mm;erfl'om cognitit;e fatigue. Vie1v.r if and proximity to nature in !IJe 1vorkplace are 
con-elated JJJitb greater entbu.ria.rm and patience for umrk and increa.red .rati~faction. Green tJieJv.r fl'om tbe bome 
may be a.r.rociated wilb reduced dome.rtic conflict. Well-tended land.rcape.r reduce .rtre.r.r and fear of violence in 
neigbborboodJ~ on the road, and at .rcbool. TheJe and otber example.r add to the li.rt oj"enviromnental rea.rom to 
gr01v more urban plant.r. 
Wolf, Kathleen L. (1998). /-Iuman Dimemion.r of !be Urban Fore.rt, fad Sheet 2- Gr01ving 1vitb Green: 
BmineJJ Di.rtrid.r and tbe Urban Fore.rl. Center for Urban Horticulture, University of Washington, 
College of Fores t Resources . 2p . 
T!Je fact .rbeet pre.renl.r a JltrJ)f.y of perception.r of urban treeJ among buJineJJ intere.rt.r including ownerJ, con/racton, 
rea/ton~ and bu.rineJJ aJJocialion .rtaff TreeJ pre.rent opportunitie.r to maximi::;_e profz!.r 1vben tbry create a po.ritit;e 
mood and di.rtinct tJiJua/ identity for patron.r lo a bliJineJJ. Tree.r indicate attention to m.rtomer .rervice out.ride the 
1val/.r if the bu.rineJJ. Concerm about urban treeJ out.ride of bu.rineJJe.r include reduced tJiJibiliry for .rqftry and 
.reatriry, engineering and debri.r impact.r, and loJJ ofjimctional .rpace. Ackn01vledging tbm co.rtJ belpJ inform 
deci.riom on planting and maintaining tbe rigbt tree.r in the rigbtplace.r. 
Wolf, Kathleen L. (1998). 1-IHman Dimen.rion.r of tbe Urban Foml, fact Sheet 3 - Urban f-'oml Val!m: 
Economic Benifi!.r ofTreeJ in CitieJ. Center for Urban Horticulture, University of Washington, 
College of Forest Resources. 2p . 
Tbe f ad JIJeet inlroduce.r a .reledion of economic ben~fit.r qfurban tree.r. S trategicplanli11g and wre enhance.r t!Je 
urban itifra.rtmcture ~ reducing beating and cooling m.rl.r, deaming the ai1~ and improving 1vater qualiry. Tree.r 
and /and.rcaping altrad m.rlomer.r to retail and mmmenia/ eli?Jironment.r and are a.r.rocia!ed JJJitb higher 
commercial/and wlue.r and higher commercial ocatpam:J' rale.r. Re.ridential property t;a/ue.r, too, are increa.red ry 
planting and retaining lree.r. 
Wolf, Kathleen L. (2003). "Social Aspects of Urban Forestry: Public Response to the Urban Forest 
in Inner-City Business Districts." journal of Arbmiad!m-e, 29(3), 11 7-126. 
6 
CitY o f Tigard Urban l'ore, try Codl' RcTi, ion' I \ 'olumc \ ' I 15(, 
*Revitalization programs are undenvqy in many inner-city business districts. An urban forestry program can be 
an important element in creating an appealing consumer environment, yet it mqy not be comidered a priority given 
that there are often mmry pl:ysical improvements needs. This research evaluated the role if trees in 
consumer/ environment interactions, focusing on the district-wide public goods protJided I?J the community forest. A 
national survry evaluated public perceptions, patronage behavior intentions, and product willingness to pqy in 
relationship to varied presence if trees in retail streetscapes. Results suggest that consumer behavior is posititJe!J 
correlated with streetscape greening on all if these cognititJe and behavioral dimensions. Research outcomes also 
establish a basis for partnerships 1vith business communities regarding urban forest planning and management. 
Wolf, Kathleen L. (2005). Trees Are Good for Business: Urban J:<orest Planning Guidelines for Business 
Assodations. Presentation, Pacific Northwest Chapter of the International Society of 
Arboriculture. 12 p. 
This presentation summarizes the results if sumrys if business patrons and research in marketing and consumer 
behavior recommending that trees be utilized to create posititJe customer e>..periences. Trees are cues if caring and 
quality and are correlated with more frequent and longer visits to businesses, greater willingness to tratJel farther 
and pqy for parking, and increased spending. Respondents to survrys preferred visiting sites with trees to those 
without trees, and positive reaction increased with tree size. 
Wolf, Kathleen L. (2005). "Trees in the Small City Retail Business District: Comparing Resident and 
Visitor Perceptions." Journal ifForestry 103(8), 390-395. 
*Many small cities and tOJvns are located near resource lands, and their central business districts seme both 
residents and visitors. Such quasi-rural retail centers face competitive challenges from regional shopping malls, 
online purchasing, and big box discount retailers. District merchants must strategicai!J enhance their market 
position to prevent out-shopping. S treetscape trees are a pf:ysil'(ll improvement that can be used to attract and 
wekome consumers. A national survry evaluated public perceptions, patronage behavior intentions, and product 
willingness-to-pqy in relationship to depictiom if trees in retail settings. Results suggest that consumer behatJior is 
positive!J associated witiJ the urban forest on multiple cognitive and behavioral dimensions. Forest amenities if 
both wild land and built environments can be used to strengthen local economies. 
Wolf, Kathleen L. (2004). Trees, Parking, and Green Law: Strategies for Sustainability. Stone Mountain, 
GA: Georgia Forestry Commission, Urban and Community Forestry, pp. 8-14. 
A critical and frequent!J OtJerlooked aspect if working tOJvard sustainability goals in communities is responding to 
the impact if paved areas, espedai!J parking lots, on the natural environment. This report describes sdentijic 
research on the iffects if parking lots and riflers strategies for improving a community's environmental performance 
with respect to automobile parking. Such strategies will address heat island iffects, air quality, stormwater runoff, 
and economic impacts. A multifaceted approadJ to mitigating the impact if paved parking areas will emplqy 
creative poliry statements and innotJative code language to promote tJegetation planting, retention, and maintenance, 
restrict parking lot geometry, and emphasize smart design. 
7 
City of Tigard Urban Forestry Code Rc,-isions I Volume V I 157 
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To: 
From: 
Re: 
Date: 
City of Tigard 
Memorandum 
Urban Forestry Code Revisions Technical Advisory Committee 
Todd Prager, Associate Planner/ Arborist 
Canopy Standards 
November 7, 2011 
During the Comprehensive Plan and Urban Forestry Master Plan processes, there was general 
consensus that the mitigation standards in the existing development code unfairly penalize property 
owners with existing trees and encourage the overplanting of replacement trees. 
Urban Forestry Master Plan goal 1.2.a recommends the city address this equity issue as part of the 
Urban Forestry Code Revisions by "(d)evelop(ing) canopy cover or tree density standards for all 
lots to be met by either preserving existing trees or planting new trees". 
The Urban Forestry Code Revisions Citizen Advisory Committee reached consensus to draft 
achievable canopy standards for development that are tiered based on zoning district. For example, 
require development in low density residential areas to have more trees than in areas of dense 
zoning, such as Downtown Tigard. 
To implement the consensus of the Citizen Advisory Committee, staff analyzed possible percent 
canopy for each zoning district using the same methodology developed to set canopy goals for the 
Urban Forestry Master Plan and an updated methodology using Light Detection and Ranging 
(LiDAR) technology (Attachment 1). 
The results of the analysis (Attachment 2) were then used in conjunction with the minimum percent 
landscaping requirements in the Tigard Development Code to place the various zoning districts 
within one of three tiers. The exception is school sites which were placed in the "dense zoning" tier 
3 to ensure sufficient room for sports fields: 
Tier 1: 40% effective canopy1 
Tier 2: 33% effective canopy2 
Tier 3: 25% effective canopy3 
1 R-1 , R-2, R-3.5, R-4.5, R-7, and R-12 
2 R-25, R-40, C-N, C-C, C-G, C-P, MUE, MUE-1, l\fUE-2, l\fUC, l\fUR, and I-P 
31\fU-CBD, l\fUC-1, 1-L, 1-H, and schools (18.130.0500)) 
City of Tiganl Urban Fore~ try Code Revi~ i ons I Volume V I 161 
Staff and outside consultants then tested the tiered standards on a wide range of development 
projects to ensure the draft effective canopy standards are achievable, result in a reasonable balance 
between trees and development, and do not force payment of fees in lieu or discretionary review for 
typical projects. 
It is important to note that effective canopy is very different from actual canopy within the lot lines 
o f a particular development. To meet draft effective canopy standards, the preservation of existing 
trees is granted double canopy credit, and planting of street trees is granted full canopy credit even 
though half o f their canopies overhang streets which are not part of the calculations. When taking 
these factors into account, the actual canopy required for a particular development will fall into the 
following ranges: 
Tier 1: 16-40% actual canopy 
Tier 2: 13-33% actual canopy 
Tier 3: 10-25% actual canopy 
The low end of each range represents sites with many ex1stmg trees that are preserved, and 
maximization of street tree canopy. The high end of each range represents sites with no existing 
trees, and no street tree canopy (all trees planted so the mature canopy stays within the lot lines). 
The possible percent canopy for each zoning district (Attachment 2) falls within the actual canopy 
range for their corresponding tiers above. Application of the tiered effective canopy standards by 
staff and outside consultants demonstrate the standards are achievable without payment of fees in 
lieu or discretionary review. Based on these analyses, staff is confident that the draft effective 
canopy standards will be achievable across the typical range of development sites in Tigard. 
ATTACHMENTS: 
ATTACHMENT 1: 
ATTACHMENT 2: 
APPROACH FOR ESTIMATING POSSIBLE PERCENT CANOPY 
POSSIBLE PERCENT CANOPY BY ZONING DISTRICT 
2 
Ciry or TigarJ Urban , .. orcstry Code RcYisions I \'olumc \ ' I /(,2 
To: 
From: 
Re: 
Date: 
City of Tigard 
Memorandum 
Todd Prager, Associate Planner/ Arborist 
Nad1an Shaub, GIS Programmer/ Analyst 
Approach for Estimating Possible Percent Canopy 
November 7, 2011 
Attachment 1 
For this analysis, "Possible Canopy Area" was calculated as the sum of the existing canopy area 
(identified in Metro's 2007 existing canopy analysis) and an estimated "Potential Canopy Area". 
The "Possible Percent Canopy" was then calculated as the Possible Canopy Area divided by the 
total taxlot area in Tigard. The approach used to arrive at a realistic estimate of Tigard's Potential 
Canopy Area and then break this estimate down by zone is oudined in the following paragraphs. 
Starting with our Tigard taxlot GIS layer, the first step in estimating Potential Canopy Area was to 
clip out all larger streams and lakes where canopy coverage may not be possible. Next, the taxlots 
were divided by residential and non-residential zoning due to the fact that there was an existing GIS 
layer that defined building footprints within the non-residential areas of town, but no such layer 
existed for residential areas. Creation of such a GIS layer from scratch would have been very time 
consuming, and there was promise of such a layer being generated by Metro using Light Detection 
and Ranging (LiDAR) by the end of the year (2009). 
Once the taxlots were divided by residential and non-residential zoning, two different approaches 
were used to calculate potential canopy area. For non-residential taxlots, the approach was quite 
simple. First, the area within fifteen feet of a building was clipped from the layer; then the existing 
canopy area was removed. The resulting shapes were considered to be candidate areas for canopy 
coverage; however, following d1e approach used in a similar canopy analysis done in Los Angeles, 
d1eir area was reduced by 50% to account for residents' desire for no additional trees and conflicts 
with higher priority uses [e.g. baseball diamonds, cemeteries]. The halved area was then used as the 
potential canopy area for the non-residential taxlots. 
For the residential taxlots, the approach was slighdy more complex. First, setbacks and minimum 
landscaping requirements in city code were compared to set an "Estimated Landscaping 
Requirement Area" of 20%. Next d1e amount of park and sensitive land area within each taxlot was 
calculated. Finally, d1e existing canopy area was calculated for each taxlot. Once these three values 
3 
Ci[y of Tigard Urban Forestry Code Rc,·isions I Volume V I 163 
Attachment 1 
were determined, it was first assumed that any ex1stmg canopy area would be in d1e park and 
sensitive land area, and that any park/ sensitive land area above the existing canopy area would be a 
candidate for canopy coverage (i.e. would be part o f the po tential). T his canopy coverage could 
exceed the estimated landscaping requirement area. However, if the park or sensitive land area 
coupled with the existing canopy area did not meet the estimated landscaping requirement area, the 
potential was increased to meet the requirement. If the existing canopy and park/ sensitive land 
canopy exceeded the es timated landscaping requirement area on buildable lands, it was assumed 
that the existing non-park / sensitive land canopy could be reduced (developed) to the estimated 
landscaping requirement area. 
T here are a couple of additional considerations to keep in mind regarding the original possible 
percent canopy analysis: 
1. T he non-residential building footprint G IS layer was drawn in 2005, so it was possible for 
some potential canopy area identified to now be occupied by a building. 
2. Parking lots are included in the potential canopy area 
3. Right of way is not included in the potential canopy area 
In 2010, Metro delivered the anticipated building footprint layer derived from LiDAR data. T his 
G IS layer included all residential and non-residential building footprints and thus could be used to 
reassess the original analysis from 2009. In November 201 0, the Possible Percent Canopy was 
recalculated using the new building footprint layer. The approach used for the non-residential 
taxlots in the original analysis was now used for bo th residential and non-residential taxlots. 
T he new LiDAR-based analysis resulted in a sizable Possible Percent Canopy increase in the 
residential zones and a slight decrease in the non-residential zones. An explanation for the increase 
in the residential zones is that the assumptions in d1e original analysis were very conservative and 
used a 20% landscaping requirement for all taxlots. The LiDAR analysis could relax these 
assumptions somewhat since the building locations were now known. T he decrease in the non-
residential zones can be explained by the fact that the building footprint layer was drawn in 2005 
and didn't include all of d1e building footprints that showed up in the LiDAR-derived layer. Since 
the new analysis still yielded Possible Percent Canopy values that were nearly d1e same or quite a bit 
greater than the original analysis, d1e new analysis introduced no concerns. 
T he final step of the Possible Percent Canopy analysis was to break down the percentages by zone. 
T his step was quite easy: when the taxlots were divided by residential and non-residential zone in 
the original analysis, they were stamped with their zoning classification. Microsoft Excel functions 
were then used to sum taxlot areas according to their zoning. 
4 
City of T igard Urban l'orcstry Code Rc,·isions I \ 'o lumc \ ' I 1(>4 
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Residential 
R-1 
R-2 
R-3.5 
R-4.5 
R-7 
R-12 
R-25 
R-40 
Sub Total 
Non-Residential 
C-C 
C-G 
C-N 
C-P 
1-H 
1-L 
1-P 
MUC 
MUC-1 
MU-CBD 
MUE 
MUE-1 
MUE-2 
MUR-1 
MUR-2 
Sub Tota 
TOTALS 
SUMMARY 
Existing Conditions (o~nal analysis) Original Analysis 
Total 
Total T axlot Total Existing Possible 
Area Canopy Area Potential o/o 
(sq ft) (sq ft) UTC (sq ft) Canopy 
1,231,814.71 358,463.73 4 1,756.41 32°/o 
2,155,715.61 860,27 1.02 50,126.42 42°;o 
12,287,992.43 4,234,914.94 129,957.86 36°/o 
99,089,225.31 34,634,276.95 6,793,158.96 42°; o 
38,756,959.73 13,597,075.70 1,707,042.98 39°/o 
26,138,548.99 6,895,256.30 2,162,582.51 35% 
12,193,061.62 3,289,036.76 9 17,610.18 35°/o 
184,179.61 34,879.56 18,417.96 29% 
192,03 7,498.00 63,904,174.94 11 ,820,653.29 39% 
367,919.39 19,467.21 127,282.38 40% 
I 5,872,021 .56 1,642,552.05 4,892,886.93 41°;o 
90,585.46 14,128.38 22,160.84 40°; o 
2,803,136.68 523,139.13 764,775.1 7 46°; o 
2,189,567.07 66,501.36 525,205.29 27°/o 
12,444,052.20 1,493,225.80 3,281,440.70 38°;o 
16,517,253.52 3,216,827.06 4,658,638.43 48°/o 
8,892,595.49 429,623.26 2,727,469.24 36% 
299,086.53 12,487.62 63,982.30 26% 
7,220,050.03 788,070.54 2,052,159.98 39°; o 
7,273,321.64 1,779,609.92 2,125,760.67 54°; o 
3,1 24,334.02 501,577.34 1,050,028.85 50°;o 
2,546,892.59 561,671.39 730,069.31 51% 
1,729,685.98 530,588.45 526,063.81 61°/o 
443,813.97 142,798.33 96,849.65 54% 
81 ,814,316.13 11 ,722,267.82 23,644,773.55 43% 
273,851,814.13 75,626,442.76 35,465,426.84 41% 
Attachment 2 
Analysis w I LiDAR building footprints 
Total 
Possible 
Potential o/o 
UTC (sq ft) Canopy 
324,922.10 55% 
369,189.74 57% 
2,151,530.55 52% 
16,878,284.34 52% 
5,576,380.35 49% 
5,146,965.53 46% 
1,9 30,690.20 43% 
15,380.1 1 27% 
32,393,342.92 50% 
127,540.80 40% 
4,774,359.02 40% 
20,588.01 38% 
727,581.12 45% 
5 13,127.87 26% 
3,277,035.02 38% 
4,628,209.32 47% 
2,557,592.36 34% 
62,953.78 25% 
1,919,575.02 38% 
1,869,000.94 50% 
889,825.36 45% 
729,597.04 51% 
451 ,245.57 57% 
75,892.79 49% 
22,624,124.02 42% 
55,017,466.95 48% 

0 ...,
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To: 
From: 
Re: 
D ate: 
City of Tigard 
Memorandum 
Urban Forestry Code Revisions Technical Advisory Committee 
Todd Prager, Associate Planner/ Arborist 
Draft Soil Volume Standards 
October 25, 2011 
The draft urban forestry code revisions include canopy standards for development based on the 
full mature growth of various tree species. A tree requires access to an adequate volume of soil 
that has not been heavily compacted in order to reach its full mature growth potential. The 
draft urban forestry code revisions includes minimum soil volume standards for street trees and 
parking lot trees because these tree types are not typically provided adequate soil volumes and 
the community has prioritized increasing canopy over streets and parking lots 1. 
The draft soil volume standards are derived from research by James Urban2 that combined data 
from several sources to graph the relationship between soil volume and tree size. 
Ultimate Tree Size 
Crown Diameter 
Projection Breast 
(sq. ft.) Height 
(inches) 
I 1200 24" 
I 
!- 900 20" 
f- 640 16" 
~ :: t 12" a· 
140 ........ 4" I 
Adequate soil volume nl!eded for 
roots can be approximated from the 
size the tree will be at maturity. 
C) 
I I I F- o ,., .==r= r • ~ ol::
.:a.. 1 : I ::t 
I I 1- 1 « I ~ 
. ~ I L l o 
I -.... 
I 1 ' 1 ~ ,_,I I I ~ 
!! 
~ 
I r,..r= I I ' c::7" I I "' I ,g
200 400 600 800 1000 1200 1400 1600 cu.ft. 
SOIL VOLUME REQUIRED 
1 City of Tigard. 2009. Urban Forestry Master Plan . City of Tigard, OR, Community Development Department, 
Conununity Planning Division. 101 p. 
2 Urban, James. 1992. Bringing Order to the Technical Dysfunction within the Urban Forest. Journal of 
.-\rboriculture, 18(2), 85-90. 
Page 1 of 2 
City of Tigard Urban Forestry Code Rc,·isions I Volume V I 169 
Mr. Urban's research represents the industry accepted standard for soil volume reguirements for 
trees·'-4•5/' . 
In developing the draft soil volume standards for street trees, staff adapted a recommended soil volume 
standard based on right o f way width (curb to property linef developed by an advisory group o f experts 
that included Mr. Urban . 
T he draft parking lot tree soil volume standard is at the upper end (1 ,000 cu. ft. per tree) of the 
aforementioned street tree soil volume standard due to relative flexibility in parking lo t design to 
maximize soil volume. 
3 Hall, Dennis J . 2007. Architectural Graphic Standards, 11th Edition. John Wiley and Sons, Hoboken, NJ. 1096 pp. 
4 Hopper, Leonard J. 2007. Landscape Architectural Graphic Standards. John Wiley and Sons, Hoboken, NJ. 11 20 
pp. 
5 Costello, Laurence R. and Katherine S. Jones. 2003. Reducing Infrastructure Damage by Tree Roots: A 
Compendium of Strategies. Western Chapter of the International Society of ,-\rboriculture, Cohasset, C.-\. 119 pp. 
6 Urban,J. 2008. Up By Roots : Healthy Soils and Trees in the Built Environment. Champaign, IL: International 
Society of ~-\rboricul ture . 479p. 
7 Casey Trees . 2008. Tree Space Design: Growing the Tree Out of the Box. Washington D.C. _-\ccessed via the 
World Wide \\feb <w\V\v.caseytrees.org/planning/design~resources / for~designers / tree~ 
space / documcnts / TrecSpaceDesignRcport.pdf> on October 24, 201 1. 
Page 2 of 2 
City of Tigard Urban l:orcstry Code Rc,·isions I \'olumc \' I 17U 
Urban Forestry Code Revisions 
Tree Canopy Fee 
City of Tigard Urban Forc~try Code Rc,-isions I Volume V I 171 
c 
To: 
From: 
Re: 
Date: 
City of Tigard 
Memorandum 
Urban Forestry Code Revisions Technical Advisory Committee 
Todd Prager, Associate Planner/ Arborist 
Draft Tree Canopy Fee 
October 27, 2011 
The draft urban forestry code revisions include canopy standards for development based on 
zoning. For example, development in low density residential areas will be required to have more 
trees than in areas of dense zoning, such as Downtown Tigard. 
The draft canopy standards have been carefully crafted and have undergone a peer review to 
ensure that they are achievable on the typical range of development scenarios in Tigard. For 
added flexibility, a discretionary review option is proposed to allow other green building or 
development methods (e.g. solar panels, green roofs, rain gardens, etc.) in place of planting or 
preserving the required amount of trees. Finally, a fee-in-lieu option is proposed to allow 
applicants to pay a "tree canopy fee" to replace the value of canopy not provided through tree 
planting or preservation. 
The tree canopy fee was developed by converting the wholesale median tree cost in the 
Willamette Valley developed by the PNWISA 1 to a unit canopy cost. According to the 
PNWISA, the median wholesale cost of a 3-inch diameter deciduous tree is $1 74. The formula 
developed by Krajicek, et al2 for open grown, broad spreading trees (maximum crown width 
(feet)= 3.183+1.829*DBH (inches)) was then utilized to convert tree diameter to canopy 
diameter. According to the Krajicek formula, a 3-inch diameter tree should have a crown width 
of 8.67 feet or crown area of 59 square feet. These dimensions were confirmed as reasonable by 
staff through several local field samples. Using the median cost of a 3-inch deciduous tree 
($17 4) and the crown area of a 3-inch diameter tree (59 square feet), the unit canopy cost or tree 
canopy fee should be $2.95 per square foot. 
1 Pacific Northwest Chapter of the International Society of Arboriculture. 2007. Species Ratings for Landscape Tree 
Appraisal. 2"d Edition, Silverton, OR: Pacific Northwest IS"-\ . 
2 Krajicek,]. E., K. E. Brinkman, S. F. Gingrich. 1961. Crown Competition- A Measure of Density. Forest Science 
7:35-42. 
Page 1 of 2 
City of Tigard Urban Fore~try Code RcY i~ions I Volume V I 173 
T his methodology is a reasonable approach for three main reasons. First, tree benefits 
(aesthetic, stormwater management, air quality, etc.) are derived primarily from their canopies, 
so proposing to place a value to tree canopy is appropriate. Second, in the proposal, tree canopy 
is valued using the median wholesale tree cost only, whereas standard tree appraisal is based on 
the wholesale tree cost plus the cost of tree installation. Finally, the Krajicek formula and field 
samples by staff are based on the maximum crown width-to-trunk diameter ratio. A typical tree 
does no t have such a high ratio. If the typical ratio were used, the unit canopy cost would 
1ncrease. 
Page 2 of 2 
City of Tigard Urban l'ore>try Code RcYi>ion > I \'olume \ ' I 174 
<
 
0 c ~ < 
:-
·-
c;ocietyo/ 0~ ~ ~~, ~ - ~ ~ + Portland State UNIVERSITY 
Regional Urban Forestry Assessment and 
Evaluation for the Portland-Vancouver Metro Area 
Prepared by Audubon Society of Portland and 
Portland State University's Department of Environmental 
Science and Management with funding from Metro 
June 2009 
(Revised june 2010) 
City of Tigard Urban l'orc, try Code Revisions I Volume V 1 177 
;.... E " 
0 ;.... 
TABLE OF CONTENTS 
Key findings ......................................................................................................................................................... 1 
Introduction ........................................................................................................................................................ 4 
Scope of work and methods ...................................................................................................................... 6 
Results and findings ....................................................................................................................................... 9 
Urban forestry policies and program narrative summaries ................................................. 14 
Regional gaps, future research and next steps .............................................................................. 29 
Appendices 
A Survey questions (Phase I) 
B Survey questions (Phase II) 
C Jurisdiction contacts 
D Researcher biographies 
E Urban forest cover protected by jurisdiction in 2007 (GIS analysis results) 
F Demographic and tree canopy data 
G Survey results (Phase I) 
H Survey results (Phase II) (Revised june 2010) 
Comparative analysis of local tree preservation regulations for private land 
Comparative analysis of local tree preservation and mitigation standards on private 
land 
K Comparative analysis of local street tree policies 
L Comparative analysis of urban forestry management 
City o f Tigard Urban Forestry Code ReYisions I Volume V I 179 

KEY FINDINGS 
Policies relating to tree removal and preservation on private land outside regulated natural 
resource areas 1 
1. There is considerable variation in local urban forestry policies and programs in the region. 
Policies and programs vary with respect to the applicability, strength and enforcement of 
regulatory elements, in the level of public investment and extent ofincentivejvoluntary 
programs for tree preservation and planting and in the level of citizen involvement and 
public/private partnerships. 
2. Twenty-five out of 30 jurisdictions have some sort of ordinance regulating tree removal or 
preservation on private land outside of riparian areas subject to water quality and habitat 
protections. 
3. The applicability of these tree removal and preservation regulations vary dramatically. The size 
of regulated trees, whether development is proposed, zoning and permit exemptions can all 
determine whether a given tree is subject to preservation, protection and mitigation standards. 
4. Seven of those 25 jurisdictions do not apply regulations consistently across all land-uses 
categories. Thirteen jurisdictions have significant regulatory exemptions that allow the removal 
of urban trees without a permit or any permit review. Eleven jurisdictions require tree removal 
permit whether development is proposed or not. Four jurisdictions have Goal 5 programs that 
regulate removal of upland tree groves. Several others regulate tree removal associated with 
hillside development. 
5. Exemptions, the limited spatial extent of regulations, and/or the absence of protection outside 
the development review process reduce the applicability and therefore the effectiveness of tree 
preservation and mitigation standards in several municipal or development codes. 
6. Where tree removal or preservations regulations do apply, the authority of local governments 
to require preservation and mitigation also vary considerably. Jurisdictions tend to fall into four 
categories with respect to the types of regulations they apply: those that emphasize 
preservation, those that emphasize mitigation, those with limited regulations, and those with 
no regulations. 
7. Few jurisdictions have clear and objective preservation and mitigation standards. Most have 
discretionary standards that are reviewed by public officials or staff. Some rely only on the 
broad policy goals and staff discretion. Six jurisdictions have the authority to require new 
development to demonstrate proposed designs will remove the least number of trees or basal 
area. 
8. Mitigation standards vary among jurisdictions that require little or no mitigation, to those that 
require 1 to 1 replacement of trees, and to those that require 1 to 1 replacement of tree 
diameter. 
9. It is difficult to assess the efficacy of compliance and enforcement of local tree regulations, but 
there appears to be a clear link to level and quality of staffing and citizen involvement. Ten of 
the 25 jurisdictions with tree regulations reported taking some sort of enforcement of 
compliance action within the last year. 
1 Th is excludes regulations involving permits or design standards related to for heritage tree programs or tree removal on 
environmentally sensit ive lands or natu ral hazard areas. This section includes regulations applying to publically-owned land 
regulated by a jurisd ict ion the same as private land. 
City of Tigard Urban Forestry Code Re,·isions I Volume V I 181 
1 
Policies relating to trees in the public right-of-way 
1. There is greater consistency in policies relating to street trees relative to those regulating trees 
on private land. 
2. Twenty-two out of 30 jurisdictions regulate street tree removal and 19 require a permit for 
removal in all cases. 
3. Twenty-two jurisdictions require street trees to be planted as a condition for approving 
development. Most jurisdictions that regulate street trees require replacement of street trees 
when they are removed and have tree planting standards relating to size, species and location. 
4. Landowners are responsible for maintaining street trees and the condition of sidewalks and 
planter strips in most jurisdictions. With few exceptions, local governments provide little or no 
funding for street tree maintenance and management. Only West Linn, Beaverton, and Tualatin 
have routine street tree maintenance programs. 
5. One of the biggest gaps in street tree policies and programs appears to exist in county urban 
service areas where permits are not required for street tree removal, policies are weak, patchy, 
or non-existent and there is less staffing and funding for urban forestry-related activities. 
Urban forestry management 
1. While most jurisdictions have some local funding sources for urban forestry related-activities, 
results indicate that the levels and sources of fund ing vary considerably. 
2. Five jurisdictions (Durham, Portland, Lake Oswego, Tualat in, and Vancouver) have an adopted 
urban forestry management plan. Gresham and Tigard have one in the works. 
3. Half of local governments have an established urban tree committee, board or urban forestry 
commission. 
4. Four jurisdictions have an inventory of urban forestry canopy (Vancouver, Tigard, Tualatin, and 
Lake Oswego) and two have established targets for urban forest cover (Vancouver and 
Portland). 
5. Eleven local governments have heritage tree programs that protect trees at landowner's 
request. 
Regional gaps and future research 
1. There are a number of areas where greater regional coordination and consistency would help 
address gaps and support local urban forestry efforts: 
• Support local governments with little or no tree removal regulations in developing policies 
for tree preservation, planting and mitigation. 
• Assist in monitoring canopy cover and setting targets for expanding the urban forest. 
• Research and disseminate best management practices for tree protection during 
construction. 
• Research and disseminate best management practices for tree mitigation. 
• Identify and eliminate barriers to protecting, managing and expanding the urban forest in 
public right-of-ways, particularly in denser urban neighborhoods. 
• Identify new funding sources for protecting, managing and expanding the urban forest. 
Cit\· ol Tiga rd Urban For~stry Cock RcYisions I \'olum~ \ ' I IR2 
2 
• Quantify ecosystem service values of urban trees at a local level. 
• Develop strategies for improving enforcement of tree preservation and protection 
regulations. 
2. Future research and assessment of local urban forestry programs should look more closely at: 
• Urban forest management in public parks and greenspaces. 
• Different levels and mechanisms for funding urban forestry related activities. 
• Compliance with tree preservation, planting and mitigation regulations and efficacy of 
enforcement activities. 
City of Tigard Urban Forestry Code Revisions I Volume V 1 183 
3 
INTRODUCTION 
In 2005 the Portland Metro region adopted the Nature in Neighborhoods program (Title 13 of the 
Regional Functional Plan) to protect and restore regionally significant fish and wildlife habitat in 
the Portland metro region. This program established land-use protections for the highest value 
riparian habitats in Metro's inventory of regionally significant fish and wildlife habitat. In adopting 
Nature in Neighborhoods, the Metro Council chose to rely on a combination of voluntary measures 
and other local programs to protect the region's upland wildlife habitat including much of the 
region's urban forest. Nature in Neighborhoods established regional performance indicators and 
targets to assess and evaluate progress toward protecting and restoring all 80,000 acres of 
regionally significant fish and wildlife habitat in the region. These measures and targets came to 
include a region-wide measure of urban forest canopy (although no target) to assess future trends. 
This regional indicator will provide a means to evaluate the efficacy of voluntary protection efforts 
and local programs to protect, enhance and manage the regional urban forest over time for its 
habitat, water quality and other environmental values. 
In order to successfully implement the Nature in Neighborhoods program and achieve regional 
performance targets, the region needs to strengthen and better coordinate local programs while 
fostering greater citizen understanding and ownership of regional performance targets. There is 
great potential in making local urban forestry programs and policies a strategic focus in engaging 
citizens and successfully implementing Nature in Neighborhoods. Despite a growing interest in 
urban forestry at a local level, a preliminary examination of local urban forestry programs suggests 
that they vary substantially across the Portland-Vancouver region. Portland State University 
planning student Clint Wertz conducted a description and analysis of municipal urban forestry 
programs in 1998 (Wertz 2000). 2 However, the region lacked an up-to-date assessment of urban 
forestry programs and policies to understand which jurisdictions are doing what and where. 
The Regional Urban Forestry Assessment and Evaluation project begins to fill this gap by 
generating and sharing a consistent body of information on local urban forestry programs in the 
Portland-Vancouver region. The project aims to provide information to support the efforts of 
citizens, planners and elected officials to improve local and regional policies and programs over 
time. Many jurisdictions are in the process of updating their urban forestry programs. Even the 
process of conducting interviews as part of this study resulted in numerous opportunities to share 
and exchange information. The project sought to assess policies and programs as comprehensively 
as possible, but additional research is needed to assess the relative success of policies and 
programs and the amount and precise mechanisms for funding urban forestry-related activities at 
the local level. The results of this project and other research combined with information on changes 
in population and forest canopy cover in the region could provide the basis for evaluating the 
success of policies and programs over time. 
Audubon Society of Portland completed the project from July 2008 to June 2009 under a contract 
with Metro. Audubon Society of Portland subcontracted with Portland State University Department 
of Environmental Science and Management to assist with research. The researchers were Jim 
Labbe, Urban Conservationist, Audubon Society of Portland, and Denisse Fisher, Ph.D. candidate at 
Portland State University Department of Environmental Science and Management (See Appendix 
D). Shayna Denny with WEST Consultants, Inc. volunteered her time to complete the GIS analysis. 
2 Clinton Everette Wertz. Municipal Urban Forestry Programs in the Portland/Vancouver Metropolitan Region. A description 
and analysis of urban forestry best management practices . Submitted in partial fulfillment of Master' s Degree in Urban and 
Regional Planning. Portland State University. March 2000. Pp. 79. 
City ofTiga rJ Urban l'orc>try CoJc Rc,·ision> I \ 'olumc \ ' I 184 
4 
Dr. Alan Yeakley also provided feedback and guidance throughout the project. Over 30 local 
government staff from jurisdictions across the region also helped complete this project. Local staff 
and a number of other citizens actively involved in urban forestry issues in the Portland-Vancouver 
region lent their time and knowledge in helping complete survey questions and participate face-to-
face interviews. 
5 
City of Tigard Urban Forestry Code Rc,-isions I Volume V I 185 
RESULTS AND FINDINGS 
Table 1 (Appendix F) provides summary data on year of incorporation (or year founded for 
counties), acreage, population, median income and urban tree canopy cover within the 30 
jurisdictions that completed Phase I surveys. Considerable variation in the age, size, median income 
and canopy cover reflect the unique histories of settlement and development over the last 200 
years and provides an important context for assessing local urban forestry programs. 
Table 1- Demographic and tree canopy data by jurisdiction 
Estimated 
Year Estimated median Acres of Percent 
incorporated population income tree canopy tree canopy 
Incorporated city/urban area or founded Acres (2008) (1999) cover (2007) cover (2007) 
Beaverton 1893 11840 86,205 47,863 3,020 25.4% 
Cornelius 1893 1293 10,955 45,959 235 18.4% 
Damascus 2004 10333 9,975 n/a 3,711 37.4% 
Durham 1966 265 1,395 51,806 144 54.3% 
Fairview 1908 2275 9,735 40,931 429 18.8% 
Forest Grove 1872 3192 21,465 40,135 858 23 .2% 
Gladstone 1911 1586 12,215 46,368 441 27.7% 
Gresham 1905 14288 100,655 43,442 4,064 27.1% 
Happy Valley 1965 3868 11,455 93,131 1,531 34.0% 
Hillsboro 1876 14665 89,285 51,737 3,384 22.9% 
Johnson City 1970 43 675 35,517 7 15.1% 
King City 1966 392 2,775 28,617 60 13.5% 
Lake Oswego 1910 7134 36,590 71,597 3,405 47.1% 
Maywood Park 1967 107 750 56,250 47 44.0% 
Milwaukie 1903 3166 20,915 43,635 757 23.9% 
Oregon City 1844 5947 30,405 45,531 1,697 27.0% 
Portland 1851 95260 575,930 40,146 27,231 29.4% 
Rivergrove 1971 114 350 85,000 57 48.3% 
Sherwood 1924 2644 16,420 62,518 541 19.8% 
Tigard 1961 7416 47,150 51,581 1,920 25.4% 
Troutdale 1907 3278 15,465 56,593 773 20.0% 
Tualatin 1913 5088 26,040 55,762 1,028 19.8% 
West Linn 1913 5037 24,400 72,010 1,977 38.7% 
Wilsonville 1969 4740 17,940 52,515 1,176 24.9% 
Wood Village 1951 603 3,100 43,384 87 14.3% 
Vancouver 1857 29485 162,400 41,618 5,425 19.7% 
Urban Multnomah County* 1854 7422 Not avail. Not avail. Not avail. Not avail. 
Urban Clackamas County* 1843 27648 Not avail. Not avail. 6,609 23 .9% 
Urban Washington County* 1849 20404 185,786 Not avail. 8,512 41.7% 
Urban Clark County* 1845 17623 Not avail. Not avail. Not avail. Not avail. 
* Unincorporated land inside Metro UBG or in Cla rk County Three Creeks Planning Area. 
Sources: 
Population for Oregon Cities: Population Research Cente r, Portla nd State University 
http://www.pdx.edu/prc/. Population for Urban Washington County: Steve Kelley, Washington County Land Use and 
Transportation Steve Kelley@co.washington.or.us. Population for Vancouver: State of Washington Office of Financial Management: 
http://www.ofm.wa.gov/pop/aprill/. Acreages of Jurisdictions: Regional Land Information System {Metro) . Median Income: US 
Census 1999. Tree Canopy for Oregon Cities : Metro State of the Watershed Report 
http://www.oregonmetro.gov/index.cfm/go/by.web/id=27579. Tree Canopy for Vancouver in ZOOS: Vancouver Urban Forestry 
Management Pla n, http:LLwww.ci.vancouver.wa.usLparks-recreationLparks trailsLurban forestryLdocsLUFMP final-web .pdf. Tree 
Canopy for Multnomah, Clackamas, Washington Counties Calculated from RLIS and Metro Urban Forest Canopy 2007 Data layer. 
9 
City of Tiga nJ Urban l'orcstry Code Rc,·isions I \'olumc \' I 186 
Phase I 
Local staff from all 30 jurisdictions completed the Phase I survey (Appendix G). In some cases 
involving smaller jurisdictions with limited staff, it was easier for us to complete the survey over 
the telephone. The majority of survey questions were answered. Questions that involved specific 
answers, such as a jurisdiction's annual expenditure on urban forestry related activities, were more 
often left blank. 
Phase II 
For the most part, we completed Phase II surveys (Appendix H) after interviews with local staff. In 
many cases questions were not applicable or could not capture the unique circumstances, practices 
or policies in a given jurisdiction. Therefore, Phase II surveys were less complete and we addressed 
specific questions or issues in the narrative summaries. 
Policies relating to trees on private land outside regulated natural resource areas. 5 
Table II, "Comparative analysis of local tree regulations for private land" (Appendix I) and Table Ill, 
"Comparative analysis of local tree preservation and mitigation standards on private land" 
(Appendix J) group and compare tree ordinances on private land and, in many cases, on publically-
owned land as well. Both tables summarize policies and standards relating to tree preservation, 
removal, mitigation and planting, excluding those applying to heritage tree programs or 
environmentally sensitive lands regulated under Goals 5, 6, and 7 of Oregon land-use planning 
programs. For the purposes of comparative analysis of policies and programs governing tree 
removal on private land, we found it useful to classify jurisdictions into the following four 
categories. 
1. Preservation emphasis: Jurisdictions that have specific tree preservation standards, criteria or 
authority to require tree preservation. These jurisdictions tend to have higher staffing levels 
and political support for implementing robust tree policies and programs. 
2. Mitigation emphasis: Jurisdictions that have general requirements for tree preservation but put 
greater relative emphasis on mitigating tree removal at greater than 1 to 1 trees. These 
jurisdictions also tend to have higher staffing levels and political support for implementing tree 
policies. In these jurisdictions higher mitigation ratios appear to provide an incentive for tree 
preservation while maintaining flexible design, but may result in less tree preservation. 
3. Some regulation: Jurisdictions without clear standards, criteria and little or no discretionary 
authority to preserve trees, that allow extensive un-permitted tree removal through 
exemptions, and/or that do not require mitigation of tree removal greater than 1 to 1 trees. 
4. No tree ordinance: Jurisdictions that do not regulate tree removal on private land. Tree removal 
regulations on private land vary significantly with respect to where and when they apply. The 
size of regulated trees, whether development is proposed, the zoning, and permit exemptions, 
all can determine whether a given tree is subject to preservation, protection and mitigation 
standards. 
Table II (Appendix I) illustrates the wide range of urban tree regulations that potentially apply to 
developed and developing properties. Twenty-five out of 30 jurisdictions have some sort of 
ordinance regulating tree removal or preservation on private land. Seven of those 25 jurisdictions 
do not apply regulations consistently across all land-uses categories. Milwaukie, for example, only 
5 Our analysis of policies relating to "tree removal on private land" excludes policies related to heritage tree programs or tree 
removal on environmentally sensitive lands or natural hazard areas. It includes policies applying to publically-owned land where 
jurisdictions apply regulations to public land. 
10 
City of Tigan.l Urban Fore~try Code Re,·isions I Volume V I 187 
applies tree regulations to development of flag lots while Portland does not regulate tree removal in 
some situations that do not involve formal land-divisions. 
Thirteen jurisdictions have significant regulatory exemptions that allow the unmitigated removal of 
trees without a permit or permit review. For example, Gresham allows three to six trees of any size 
to be removed within a 12 month period depending on lot size. Beaverton entirely exempts 
developed properties less than 1/z acre and has annual exemptions on developed properties greater 
than Yz acre. 
Another gap in most local tree preservation ordinances is the lack of any permit required for tree 
removal outside the development review process. Eleven jurisdictions always require tree removal 
permits, whether development is proposed or not. Many jurisdictions do not have clear procedures 
for ensuring trees that are preserved as a condition of past development are not cut after a 
development application is approved. Instead these jurisdictions tend to rely on citizen complaints 
or inquiries in lieu of an established permit process. Other jurisdictions have specifically addressed 
this issue by requiring a permit to remove any tree above a minimum size even if tree removal is 
granted without review. 
Exemptions, the limited spatial extent of regulations, and/ or the absence of protection outside the 
development review process reduce the applicability and, therefore, the effectiveness of tree 
preservation and mitigation standards in several municipal or development codes. 
Where tree removal or preservation regulations do apply, the authority of local governments to 
require preservation and mitigation also varies considerably, as illustrated by Table Ill (Appendix 
J). Only Portland, West Linn, Oregon City and Vancouver have clear and objective criteria for tree 
preservation. Most jurisdictions that regulate tree removal have discretionary criteria that staff or 
public officials must consider before granting a tree removal permit. However, not all of these 
standards and criteria- whether discretionary or clear and objective- can or do require applicants 
to avoid and minimize tree removal by demonstrating a low or least impact design. Six jurisdictions 
have the authority to require new development to demonstrate that proposed designs will remove 
the least number of trees or basal area. Finally, mitigation standards vary among jurisdictions that 
require little or no mitigation to those that require 1 to 1 replacement of trees and to those that 
require 1 to 1 replacement of tree diameter. 
Specific regulatory requirements are important to ensure that new development avoids and 
minimizes tree loss. However, in interviewing local staff and citizens, the efficacy of regulatory 
programs also depends on local political leadership, staffing levels, the level of citizen involvement 
and associated enforcement efforts. For example, Wilsonville's code consists of a highly 
discretionary review process for determining tree preservation, removal and mitigation and 
specific criteria for tree removal that are not exceptionally restrictive or protective relative to other 
jurisdictions. However, per-capita staffing levels and expertise allow the city to work more actively 
and effectively with developers and landowners than other jurisdictions, ensuring the technical 
expertise and follow-through needed to implement policies and enforce requirements that preserve 
trees, minimize impacts or more effectively mitigate tree removal. 
It was difficult to assess the efficacy of enforcement of tree regulations by local governments. Some 
local staff admitted and many citizens actively involved in urban forestry issues asserted that 
enforcement of tree regulations is weak and inconsistent. But in other jurisdictions, staffing levels 
or organized citizen advocates clearly improve enforcement of tree regulations. To provide a litmus 
test of a local government's enforcement activities related to tree preservation and protection, we 
asked each jurisdiction whether or not they had taken enforcement action or compliance efforts 
11 
CitY oi 'I'i!o>ard Urban l ;or~stry Code R~,· isions I \'olumc \ ' I IHH 
related to their local tree regulations sometime in the past year. Ten of the 25 jurisdictions with 
tree regulations reported taking some sort of action in the last year. 
Policies and Programs Relating to Trees Public Right-of-Way 
Table IV, "Comparative analysis of local street tree policies" (Appendix K) compares basic 
components of local street tree policies and programs in the Portland-Vancouver region. In general, 
there is greater consistency in policies relating to street trees relative to those regulating trees on 
private land. Most jurisdictions- 22 out of 30- regulate street tree removal to some degree and 19 
require a permit in all cases. Twenty-two require street trees to be planted as a condition for 
approving development. Most jurisdictions that regulate street trees require replacement of street 
trees when they are removed and have tree planting standards relating to size, species and location. 
Most also make landowners responsible for maintaining street trees and the condition of sidewalks 
and planter strips. With few exceptions, local governments provide little or no funding for street 
tree maintenance and management. West Linn, Beaverton, and Tualatin have routine street tree 
maintenance programs. 
Smaller jurisdictions tend not to make policy distinctions between trees located on private land and 
those located in the public right-of-way. For example, Durham and Rivergrove lack a significant 
number of street trees and cover street trees under a general tree-cutting ordinance. Cornelius and 
Sherwood report being able to police street tree removal without a specific permitting process for 
removal. One of the biggest gaps in street tree policies and programs appears to exist in county 
urban service areas where permits are not required for street tree removal, policies are weak, 
patchy, or non-existent and there is less staffing and funding for urban forestry-related activities. 
Urban forestry management: funding, planning, voluntary programs and partnerships 
Table V, "Comparative analysis of urban forestry management" (Appendix L) details the wide range 
of staffing, fund ing and programming levels relating to urban forestry among local governments in 
the region. While most jurisdictions have some local funding sources for urban forestry-related 
activities, our results indicate that the levels and sources of funding vary considerably. Five 
jurisdictions (Durham, Portland, Lake Oswego, Tualatin, and Vancouver) have an adopted urban 
forestry management plan, while two more (Gresham and Tigard) have one in the works. Half of 
local governments have an established urban tree committee, board or urban forestry commission. 
Four jurisdictions have an inventory of urban forestry canopy (Vancouver, Tigard, Tualatin, and 
Lake Oswego) and two have established targets for urban forest cover (Vancouver and Portland). 
Ten jurisdictions have a certified arborist on staff. Eight jurisdictions have a dedicated tree fund 
that pools in lieu planting or penalty funds. Eleven local governments have heritage tree programs 
that protect trees at landowner's request. 
GIS analysis of natural resource overlays and water resource regulations 
The extent of existing urban forest canopy and regionally significant habitat varies considerably 
among jurisdictions.6 This is clearly a product of historic land-use patterns, both pre-urban 
agricultural uses and more recent urbanization. State or regional law requires jurisdictions to limit 
tree removal adjacent to streams and wetlands to protect water quality, fish and wildlife habitat, or 
public health and safety. Four jurisdictions- Portland, Wilsonville, Lake Oswego and Hillsboro-
have Goal 5 programs that preserve upland forests inside the 2002 UGB, and Beaverton and 
6 Note that recent analyses in the Metro State of the Watershed Report assessed forest cover within unincorporated areas 
within Metro's Boundary however this analysis assessed unincorporated areas ins ide the UGB. 
City of Tigard Urban Forestry Code Re,·isions I Volume V I 189 
12 
Washington County require mitigation when development displaces upland forests. Other 
jurisdictions like Gresham and Tigard regulate tree removal associated with hillside development. 
Appendix E provides the results by jurisdiction from the GIS analysis of natural resource overlays 
and water resource regulations that preserve tree canopy, mitigate removal of trees, or otherwise 
protect regionally significant wildlife habitat (not all of which includes tree canopy). Results 
indicate that jurisdictions provide a wide range of protection for their existing urban forest canopy 
through natural resource overlay zones or other regulations applying to environmentally sensitive 
lands. Jurisdictions like Gresham and Wilsonville mostly protect a relatively high percentage of 
their existing urban forest canopy with natural resource overlay zones (38.4% and 37.4% 
respectively). In contrast, jurisdictions like Damascus, Wood Village, Cornelius and Milwaukie 
mostly or partially protect a relatively small percentage of existing urban forest canopy (0%, 6. 7%, 
7.4%, and 9% respectively) with overlay zones or other regulations. 
13 
City ofTiganJ Urban l'orcs try Cod~ 1( ~, - i siom I \ 'olumc \' I I<Jil 
URBAN FORESTRY POLICIES AND PROGRAM NARRATIVE SUMMARIES 
The following narrative summaries detail the specific elements of local urban forestry policies and 
programs while highlighting strengths, weaknesses and unique circumstances that characterize 
programs in individual jurisdictions. In surveying local governments' urban forestry policies and 
programs throughout the entire region, several features of individual jurisdictions stand out as 
exceptions in their apparent strength, effectiveness, scope or comprehensiveness. 
In terms of regulatory programs applying to private land, there are several local government 
programs that stand out for one or more characteristics. Lake Oswego and Portland both have the 
most extensive programs for protecting upland tree groves. Lake Oswego's tree removal 
regulations are particularly thorough at addressing tree removal outside the development review 
process and in situations involving annexation. Portland's tree regulations for land division provide 
particularly detailed regulations for preserving trees of different species. Tigard and Oregon City 
have some of the strongest provisions for mitigating tree removal, requiring mitigation based on 
regulated tree diameter with few exceptions. Most other jurisdictions require replacement of 
mature trees with a single sapling. Vancouver's tree regulations include a minimum tree density 
requirement that can be achieved by either planting or preservation and discretionary provisions 
to preserve trees of particular ecological or social significance. This mix of clear and objective 
standards and discretionary criteria provide for both consistency and flexibility in application. 
Several local governments have particularly strong or comprehensive urban street tree programs. 
The City of Portland's Neighborhood Tree Liaison Program provides an exceptional level of training 
and education to local citizens. Portland has also invested heavily in street tree stocking inventories 
and funded extensive street tree planting. Beaverton has an especially thorough street tree 
maintenance program. 
Most cities require street tree planting as a condition of approving development but frequently tree 
planting is lowest on the priority of right-of-way improvements or are not planted due to a higher 
priority given to driveways, intersection sightlines, utilities and other aspects of the built 
environment. To address this issue in its planned Villebois community, Wilsonville has developed a 
system of prioritizing right-of-way improvements to ensure that street tree planting is given higher 
priority. Oregon City addresses the issue by requiring a set number street trees to be planted based 
on the length of street frontage associated with a new subdivision lot. If one or more street trees 
cannot be accommodated due to the placement of driveways, utilities, signage and other built 
infrastructure, developers must pay into a tree planting fund that pays for trees to be planted on 
public land at other locations in the city. 
Few jurisdictions have conducted urban forestry management plans. Vancouver, Portland and Lake 
Oswego have the most recent Urban Forestry Management Plans. Vancouver and Portland include 
specific goals and targets for expanding urban forest cover. The City of Portland also has an Urban 
Forestry Action Plan and has produced a number of other reports quantifying the ecosystem 
service value of the urban forest. 
City of Beaverton 
Beaverton has been part of Tree City USA for the last 15 years. Beaverton has a particularly 
thorough street tree maintenance program with a set schedule for inspecting and maintaining all 
street trees every three years. 
Beaverton first adopted regulations related to preservation of Significant Natural Resource Areas in 
1985 (ORO 3441).1n 1990 Beaverton adopted regulations for Preservation ofTrees and Vegetation 
14 
City o f Tigard Urban Fore~try Code R e,· i s ion~ I Volume V I 191 
(0 RD 37 40), outlining specifics for tree protection, pruning and removal while refining the 1985 
regulations. Revisions to the regulations for preservation of trees and vegetation within the 
Development Code occurred over time with the most recent edits adopted in 2006. 
Several types of trees are regulated by Beaverton's development code and defined within Chapter 
90: 
• Significant individual trees or tree groves -Trees and groves that have been identified as 
possessing exceptional characteristics and are mapped on the city's Inventory of Significant 
Trees and Groves (60.60) 
• Historic trees or tree groves - Trees of historic significance due to their association with 
historic properties or the general growth and development of the city (60.60) 
• Landscape trees -Trees that have been preserved or planted as part of an approved landscape 
plan (40.20 and 60.05) 
• Street trees -Trees located within the public or private right-of-way or easement for vehicular 
access, or associated with public utility easements (60.15) 
• Trees within a significant natural resource area (SNRA includes wetlands and riparian 
corridors) - Trees located within Goal 5 areas (60.67) 
• Community trees - Healthy trees of at least ten inches (10") DBH located on developed, 
partially developed or undeveloped land; also includes trees of at least of 6" for various native 
species (60.60) 
• Mitigation trees ( 60.60) -Trees planted in an effort to alleviate the impact of the removal of 
other trees; a mitigated trees takes on the designation of the tree removed 
The city just finished updating a Tree Inventory Map, effective April 30, 2009, that combines the 
contents of previous mapping efforts and reflects recent changes. Currently, there are no plans to 
change the development code as it relates to trees and tree regulations. 
Clackamas County, unincorporated urban 
Clackamas County has extensive and detailed comprehensive plan language relating to urban 
forests and trees under Chapter 3 for "Natural Resources and Energy." Policy 6 for "Forests" calls 
for initiating "a tree conservation and planting program for the northwest urban area to preserve 
urban forest areas and promote tree landscapes." Specific implementation items under this policy 
include an urban forest inventory; adoption of tree conservation standards in design review, 
grading and subdivision ordinances that minimizes removal of trees and vegetation on 
undeveloped lands within the urban area; development of a urban street tree planting and 
maintenance program; and creation of a special review process for commercial timber harvesting 
within the urban area. 
Despite the breadth and specificity of the comprehensive plan policies, the County has yet to 
implement them, in part due to funding constraints. Outside the recently adopted Title 13 Habitat 
Conservation Areas and the Willamette Greenway overlay zone, zoning and development 
ordinances (ZOOs) have limited and nebulous code language relating to tree preservation and 
protection inside the Metro UGB. The regulations only apply to new single-family subdivisions and 
no permit is required for tree removal outside a development application. The County's heritage 
tree program is entirely voluntary and affords no protection for designated heritage trees. The 
County has tree-planting requirements for parking lots but only requires street tree planting along 
a few designated boulevards and in the Sunnyside Village District. Clackamas County is currently 
undergoing a planning process to adopt more explicit code language governing tree preservation 
15 
CitY of Tigard Urban l'orcstry Code RcYisions I \'olumc \ ' I 1'12 
and protection. A recently convened Urban Tree Task Force aims to improve existing ZOOs to better 
implement urban tree and forest related policies in the comprehensive plan (see below). 
In September 2008, the Clackamas County Board of Commissioners appointed the 13-member 
Trees Task Force, charged to recommend changes to the ZOOs "to assure that the tree canopy is 
maintained, preserved and enhanced, by controlling predevelopment tree cutting without 
prohibiting development." The citizen task force is also charged with making other 
recommendations "to contribute to long-term management of the County's urban forest reserves." 
Clark County, unincorporated urban 
Clark County has no urban forestry policies or programs. The County's development code does 
require landscaping associated with development within the public right-of-way including 2-year 
maintenance and survival requirements (Subtitle 40.320.020), but no specific standards require 
tree planting. Clark County's critical area ordinance (Subtitle 40.4) governs tree removal in areas of 
critical natural resource concern, mainly along streams, wetlands, shorelines and geologic and flood 
hazard areas. Title 40 requires development and redevelopment to avoid, minimize and provide 
compensatory mitigation for any impacts to critical area functions and values such that there is no 
net loss in those functions and values. This includes the functions and values provided by trees and 
other woody vegetation. Clark County also has forest practices regulations that govern conversion 
of forest land to other uses and ensure that the County's critical areas ordinance is applied in these 
situations. 
City of Cornelius 
Cornelius has limited urban forestry policies and programs and is one of a handful of jurisdictions 
in the region that do not have Tree City USA status. Cornelius does not regulate tree removal on 
private land outside its Natural Resource Overlay and does not have a permit process for removing 
street trees, although staff report that they are able to police street tree removal effectively given 
Cornelius is roughly two square miles in area. Cornelius's development code Title 17 for 
subdivisions does require the planting of street trees as part of frontage improvements for street 
construction. Trees must be installed along every 30 lineal feet of street frontage in accordance 
with an approved public works street tree list. City Transportation System Plan details required 
planter strip widths for new streets; they range from 4 to 6 feet for residential streets. 
City of Damascus 
As Oregon's newest city, Damascus does not have an adopted comprehensive plan and zoning code. 
Therefore it does not currently regulate tree removal as a part of development. However, an 
increase in clear cutting and tree removal has emerged as a major issue of community concern. To 
address this issue the Damascus City Council adopted an interim tree-cutting ordinance in 2007 to 
prevent the wholesale clearing of trees in advance of pending comprehensive plan and zoning 
decisions. The Council has renewed the ordinance continuously since 2007 (most recently May 4, 
2009). 
The ordinance prohibits the clear-cutting of trees within the urban growth boundary (UGB) of the 
city with the intent to protect citizens of the city from personal injury and property damage due to 
an increased susceptibility to wind and other hazards to public peace, health and safety resulting 
from clear cuts. The ordinance is interim until the city can consider and adopt long-term legislation 
regulating forest practices, tree preservation and habitat protection. This ordinance is expressly not 
intended as be a moratorium on construction or land development, function as a land use 
regulation, implement Metro Title 13 (Nature in Neighborhoods), or regulate forest practices. 
The ordinance's most significant provision is a prohibition on clear-cutting defined as "the removal 
of more than ten (1 0) trees, from a parcel or from adjoining parcels in common ownership, within 
16 
City of Tiganl Urban Forestry Code Rc,·isions I Volume V I 193 
any twelve (12)-month period; or the removal of more than five trees from a parcel that leaves less 
than an average of one tree per 1,000 square feet of lot area, distributed throughout the entirety of 
the site." The ordinance includes a provision for permitted removal of hazardous trees. 
The City of Damascus and local citizens are currently in the process of developing a comprehensive 
plan and zoning designations including conservation overlays. The community has repeatedly 
expressed the desire to conserve forested buttes in Damascus for scenic values, wildlife, water 
quality and sense of place. The city is on schedule to adopt policies to protect natural features in 
some form within the coming year. 
City of Durham 
Like many smaller jurisdictions Durham does not have Tree City USA designation, an urban forestry 
committee or tree board, or a heritage tree program. However, Durham is known for its extensive 
urban forest cover and for prioritizing tree preservation. It is also one of a handful of jurisdictions 
that have an adopted urban forestry plan. Durham reports spending roughly $1,000 on urban 
forestry-related activities in the 2007/2008 fiscal year, provided by development fees and general 
fund allocations (property taxes). 
In 1975, the city passed its first tree ordinance prohibiting the cutting of trees on both public and 
private property without a permit whether or not development is proposed. Tree regulations are 
mostly located within their development code, but some requirements can also be found within the 
comprehensive plan. The city does not actively regulate trees in the public right-of-way, as very few 
actually exist in association with a particular property. Durham's tree ordinance (Ordinance 
Number 228-05) applies to all trees;;:: 5 inches in diameter within the city limits, regardless of their 
location. Unless a tree is dead or hazardous, all tree removals must be approved by the city's 
planning commission and require a permit. The cost for a tree removal permit is $10 per tree, plus a 
$5 application fee. Emergency removals require an emergency permit and do not have a fee, as 
determined by the city administrator. 
City of Fairview 
Fairview has Tree City USA designation but no adopted urban forestry plan or established tree 
board/committee or urban forestry commission. Fairview funds urban forestry-related activities 
through stormwater fees and city general fund allocations. 
Fairview defines "significant vegetation" as trees with a diameter of;;:: 6 inches, except for non-
native, invasive species. The city protects "significant vegetation" associated with some 
development and public work projects. No trees can be planted or removed in the public right-of-
way and public property without permission of the city public works director and a tree removal 
permit. Street trees must be planted no more than 30 feet apart for all developments that are 
subject to land division and site design review. However, street tree standards may be waived when 
trees preserved within the front yards provide the same or better shading and visual quality as 
street trees. The city requires the developer to provide a performance bond in an amount 
determined by the city engineer to ensure the planting and care of street trees during the first two 
years after planting. After this time period, street trees become the responsibility of landowners. If 
street trees are removed they must be replaced with trees of the same type (coniferous or 
deciduous). While not clearly delineated within its code, the city requires on-site mitigation for 
regulated trees as part of the development process and for the replacement of street trees (unless 
trees are hazardous). The mitigation standard stands at 1:1 tree. Mitigation trees must be 1 Vz inch 
caliper if deciduous and six inches in height if coniferous. 
17 
CitY of Tigard Urban J.'ore>try Code Re,·i>iom I \'olumc \ ' I 1'!4 
City of Forest Grove 
Forest Grove has had tree-related policies regulations and a tree board/committee in place since 
1992, the year it received Tree City USA status. Forest Grove does not have an urban forestry plan 
but is the only jurisdiction in the region that has a street tree inventory for its entire street network. 
In March 2009, Forest Grove adopted new tree-related regulations and administrative practices to 
better address tree preservation in the land division and development review process. The new 
code (10.5.100) clarifies when and where tree regulations apply. The new code also requires a tree 
removal permit to occur earlier in the development permitting process, adds requirements for 
development applications involving regulated trees, and revises tree preservation and mitigation 
standards. Forest Grove does not require a permit to remove trees on private property outside the 
development process, although there are specific criteria for removing trees that were preserved as 
a condition of past development. Owners of significant "registered trees" are notified annually of 
their responsibilities that include a public hearing before tree removal. Depending on the code, tree 
removal decisions are discretionary decisions of staff, the planning director, or the Community 
Forestry Commission. Forest Grove applies a slightly modified version of Metro's Title 13 model 
ordinance to habitat conservation areas. The city requires tree planting for new developments in 
parking lots, along streets and in buffer areas between zones and provides limited funding for 
neighborhood tree planting. 
City of Gladstone, urban 
Gladstone only manages trees within parks and lacks a tree ordinance for private land. Within 
parks, if trees need to be removed, the city hires an arborist. There is no permitting system for tree 
removal on private property or in the public right-of-way. Existing street tree maintenance is the 
responsibility of property owners, except for any street trees that have been planted by the city. 
The city has limited staff and budget and water and sewer services have been a budgeting priority. 
Gladstone's landscaping standards require 15% of a property to be landscaped as part of most new 
development. However, no tree planting or placement standards exist. Trees are also informally 
protected within riparian areas as part of the city's acknowledged GoalS program that will be 
updated before the end of the year in order to substantially comply with Metro Title 13. Gladstone 
has no tree committee or urban forestry commission, does not have Tree City USA status, and has 
no adopted urban forestry plan. 
City of Gresham 
In 2009, Gresham became the newest jurisdiction in the Portland-Metro area to achieve Tree City 
USA status. Gresham has had tree regulations that apply both during development and outside of 
the development review process for over 10 years. Development Code Section 9.1000 covers all 
regulated trees and Section A14.004 applies to significant trees. Gresham has three overlay zones 
that either directly require or indirectly result in retention of trees when properties are developed 
and requires planting of street and parking Jot trees as a condition of new development. Gresham 
funds urban forestry-related activities through a combination of storm water fees, development fees 
and grants. The staff reported some $600,000 dedicated to urban forestry-related activities in the 
2007-2008 fiscal year. 
Gresham hired an urban forestry planner in 2008 who reports to the planning director. The urban 
forestry planner is charged with a number of tree-related responsibilities including drafting an 
Urban Forestry Management Plan in 2009 and subsequent review and revision of tree-related 
codes in 2010. The city also renamed and reconstituted its Tree Preservation Committee into a 
newly formed Urban Forestry sub-committee to the Natural Resource and Sustainability Advisory 
Committee. 
18 
City of Tigard Urban Forestry Code Rc,·isions I Volume V I 195 
City of Happy Valley 
Happy Valley adopted its tree regulations five years ago and achieved Tree City USA in 2008. Its 
planning commission acts as its tree board. The city does not have an adopted urban forestry 
management plan and has yet to develop a heritage tree program. Happy Valley reports spending 
$70,000 on urban forestry-related activities in the 2007/2008 fiscal year, provided by development 
fees. 
In May 2009, the city adopted new code and comprehensive plan amendments. Happy Valley 
requires a permit for trees ;::: 6 inches at four feet whether or not development is proposed. The city 
applies different discretionary standards for tree preservation depending on zoning and whether 
and what type of development is proposed. Tree mitigation is required for all zones and can be 
greater than 1:1 when development is proposed. Happy Valley has special regulations that apply to 
newly annexed lands. Street trees must be planted depending on district and landscaping 
standards. These requirements include tree planting and buffering requirements for parking lots. 
Native, nuisance and prohibited plant lists can be found in Appendix A of the development code. 
City of Johnson City 
Johnson City has no urban tree or forestry related policies or programs. 
City of Hillsboro 
Urban forestry goals and policies have been embedded in Hillsboro's comprehensive plan for 30 
years. In 2005, the revised Hillsboro 2020 Vision and Action Plan (a guiding community vision 
document and not adopted policy) included a new strategy to establish a tree planting, 
maintenance and preservation organization and program over the coming years. Other strategies in 
the action plan address the preservation of natural resources including trees. Hillsboro currently 
does not have an urban forestry plan, an urban tree board or commission or Tree City USA status. 
Hillsboro has limited tree preservation or protection standards outside its natural resource overlay 
zone; however, the overlay zone does include some protections for upland forests. Mature trees on 
private land listed on the city's cultural resource inventory or within station community planning 
areas (near light rail stations) are regulated and can be preserved as a condition of development. In 
addition, staff reports that some new development approvals include conditions of approval 
designed to preserve and protect trees on private land but no specific code language was cited. 
Street tree planting is required with new development in Hillsboro. All street trees must be planted 
in compliance with city standards. Property owners in Hillsboro are responsible for the 
maintenance of adjacent trees within the public right-of-way. Hillsboro does require a permit for 
street tree removal in most parts of the city. However, mature street trees listed in the city's 
cultural resource inventory and within Hillsboro's Orenco Townsite Conservation District are 
regulated. For example, mature street trees within the Orenco Townsite Conservation District may 
be removed only with prior permission from the planning department based on a report from a 
registered arborist. Mature street tree removal in this district must be supervised by a registered 
arborist or professional tree service, and tree replacement standards are in place. 
In 2003, Hillsboro adopted a Goal 5 Natural Resources Management Plan that included a Significant 
Natural Resource Overlay (SNRO) District. The SNRO requires new development in or near mapped 
natural resource areas- including some upland forests - to avoid, minimize or mitigate impacts and 
these impacts include those associated with tree removal. 
Hillsboro is in the process of completing a citywide street tree inventory using ArcGIS-based 
software loaded on handheld computers. The location, species, size and condition of 14,000 street 
trees have been catalogued by community residents, 4-H youth, and university student interns 
since 2005. The anticipated inventory completion date is fall 2009. 
CitY of Tigan.l Urban l;orc>try Code RcYisiom I \ 'olumc \ ' I I '.I(> 
19 
City of King City 
According to King City's comprehensive plan, the protection of all regulated trees is to be 
encouraged so that the "removal of existing trees should be limited to what is necessitated by land 
development, safety and disease." The city regulates trees that are 2: 6 inches at four feet. City policy 
aims to limit the removal of existing trees to what is necessitated by land development, safety and 
disease. 
King City adopted its current tree regulations in 2004 under Chapter 16 of its municipal code. This 
chapter covers tree preservation on developable properties, which require the submittal of a site 
plan that includes a description of all trees that are to be retained or removed. Trees are also to be 
protected under best management practices during construction. The city keeps a list of any 
vegetation listed on a plat map or a document recorded with the plat. 
King City has no designated funding source for urban forestry, does not have a designated tree 
committee or urban forestry commission, an urban forestry plan, or Tree City USA designation. 
City of Lake Oswego 
Since it initiated its tree preservation efforts over a decade ago, Lake Oswego has had one of the 
most comprehensive urban forest programs in the region. The city has had Tree City USA 
designation since 1990 and adopted a new urban forestry plan in 2007. According to their 
comprehensive plan, Lake Oswego emphasizes tree preservation rather than mitigation. A previous 
study on this region's urban forestry policies identify the city of Lake Oswego as one of the most 
active in terms of monitoring and maintenance programs, both for trees on private property and in 
the public right-of-way. This study recognized that Lake Oswego has some of the most stringent 
tree preservation standards in the Portland-Vancouver Metro region (Wertz, 2000). 
According to their comprehensive plan, the city must develop a planting and maintenance program 
for trees in public right-of-way, open spaces and parks. Unfortunately, this request was not funded 
this year. The plan also explains that the city will preserve natural resource sites, through public 
acquisition and other methods such as conservation easements, to permanently preserve trees and 
tree groves. Lake Oswego Parks and Recreation is primarily responsible for acquiring conservation 
easements to protect valuable forest habitats, such as oak savannah. 
Lake Oswego adopted a new tree preservation ordinance in 2007 and established a Tree Code Task 
Force that evaluates and provides amendments to the new tree code. This task force includes an 
arborist from the Community Forestry Commission, a general arborist, a Natural Resources 
Advisory Board (NRAB) representative and local residents. Meanwhile, the Community Forestry 
Commission was formed to hear requests concerning Type II tree cutting permits. 
Tree removal is regulated under Lake Oswego's Code (Chapter 55) and the Sensitive Lands Code 
(Chapter 50). Chapter 50 permits removal of up to two trees greater than 10" dbh a year on single-
family residential zones unless the trees are 1) protected as a condition of past development; 2) 
designated as a Heritage Tree; or 3) located within a Resource Conservation (RC) or Resource 
Protection (RP) overlay district. The city also provides detailed tree protection instructions during 
development. 
City of Maywood Park 
Maywood Park has no urban forestry-related policy goals in its comprehensive plan but has had an 
ordinance regulating tree removal since 1989. The city requires some tree planting as a condition of 
development. Removal permits are required for trees on private land and in the public right-of-way. 
In the latter case, the city tracks street tree planting and removal and also funds some tree planting 
in the public right-of-way. Urban forestry activities are funded by tree removal permit fees. 
Maywood Park does not have Tree City USA designation, an adopted urban forestry plan, or an 
20 
City of 'l'i,[,'ll rd Urban Forestry Code Rc,·isions I Volume \' I 197 
established tree committee or urban forestry commission. However, the city does have a volunteer 
city forester. 
City of Milwaukie 
Milwaukie has had a tree ordinance governing tree removal for 10 years. However, these only apply 
to trees located in the public right-of-way and trees on flag lots, and the latter only when 
development is proposed. The city council considered broader tree regulations in the past but these 
were never adopted. The city's Willamette Greenway zone and Water Quality Resource Areas also 
govern tree removal. Milwaukie provides imited funding for urban forestry-related activities 
through its engineering and code enforcement divisions. Milwaukie does not have Tree City USA 
designation, an adopted urban forestry plan or an established tree committee or board. 
Multnomah County, urban unincorporated 
Multnomah County has very little land to which it provides urban services and planning. 
Multnomah County regulates tree removal on this small amount of urban service area through an 
agreement with the City of Portland. Therefore, the applicable regulatory policies relating to tree 
removal, preservation and planting are the same as the City of Portland. Multnomah County does 
not have a tree board or urban forestry commission, an urban forestry plan or Tree City USA 
designation. 
City of Oregon City 
Oregon City's tree ordinances have been in place for more than a decade. The city's comprehensive 
plan identifies the need to develop better policies to protect its urban forest, as the "total tree cover 
in the city has diminished" as result of development. Oregon City has created tree regulations that 
apply during development, annexation and land division. Annexations (14.04.050), subdivisions 
(16.08.040) and multi-family and commercial/industrial development (16.12) require site plans 
that identify, among other features, wooded areas, isolated trees (all trees :2: 6" dbh) capable of 
being preserved and significant natural resource areas. 
For new development in single-family residential zones, the development code requires that all 
regulated trees "shall be preserved outside the building area, which is defined as right-of-way, 
public utility easements and within building setbacks." According to the code, all regulated trees 
will remain after development of the site if it is situated in a building setback, is part of landscaping, 
a public park or landscape strip, or legally reserved open space; is in or separated from the 
developable remainder of a parcel by an undevelopable area; or is on the applicant's property and 
not affected by the development. Oregon City currently does not waive building setback 
requirements to preserve trees. Oregon City does not currently have tree preservation standards 
that could modify subdivision design. Nor are there discretionary development standards that 
could require adjustments of building or driveway areas to preserve regulated trees. 
Oregon City allows tree removal outside development application and without approval, on all 
private land with a few exceptions. Additionally, approval for regulated tree removal must be 
applied for in private properties located in a) the Canemah National Registered Historic District; b) 
designated historic structures; c) the Unstable Slope Overlay District (slopes over 25% and other 
unstable areas) ; d) the Water Quality Resource Overlay District (within 200 feet of stream or 
wetland); and f) outside single-family residential zones. Additionally, in commercial zones all 
regulated trees within the property must be mitigated. There is currently no permit system to track 
tree removal and replacement outside the development review process unless the tree is in the 
public right-of-way. 
Chapter 12.08 regulates community forests, heritage trees and street trees. The city also requires 
planting of street and parking lot trees as a condition to most new development. Overall, the city's 
City o f Tigard Urban Fo restry Co de RcYisions I \ 'olumc \ ' I 1\IH 
21 
focus is on retaining canopy cover, with a large emphasis on tree mitigation during development 
and within sensitive areas. Oregon City is currently in the process of revising its tree regulations, 
which should be completed sometime this year. The city is also updating its natural overlay district 
(17.49) to comply with Metro's Title 3 and 13. Historic/heritage trees are regulated by the city. 
Heritage trees are to be designated by the Natural Resources Committee. A process for designation 
of Heritage Trees has been written into the latest code amendment, but no trees have been 
designated yet. 
Oregon City does not have Tree City USA designation, an established urban tree committee or 
board, or an adopted urban forestry plan. 
City of Portland 
Portland first received Tree City USA designation in 1979. In 1995 Portland adopted its first urban 
forestry management plan and its current tree regulations and urban forestry commission. The City 
of Portland's urban forestry plan was revised in 2004 and followed by an Urban Forestry Action 
Plan in 2007. Both these documents and the comprehensive plan contain policies relating to urban 
forestry in Portland. Other than Vancouver, it is the only jurisdiction that has explicit targets for 
urban forest canopy cover by land-use category. Portland has an established Neighborhood Tree 
Liaison Program that has trained neighborhood representatives as neighborhood tree stewards 
(NTS) in urban tree care and the city's urban forestry rules and programs. The Parks Urban 
Forestry Division offers a 7 -session course to prospective NTSs that educates stewards on general 
tree care, tree biology, tree planting, preservation and identification. Once trained, NTSs work with 
Portland Parks and Recreation staff on tree projects in their neighborhood. 
Various city codes and chapters regulate tree removal, protection and mitigation depending on the 
location, size, species, land use zone and type of development proposed. On a single property, 
regulations may vary further depending on size of property, size of trees and canopy cover, 
whether it is public or private ownership, the type of development proposed, whether the property 
is developed, or whether the tree was preserved as a condition of past development. Since 1972 
Portland Parks and Recreation's (Parks) Urban Forestry Division has regulated trees in parks and in 
the public right-of-way (Chapter 20.40). Since 1995 the parks department has also regulated tree 
removal on private property in instances that do not involve development (Chapter 20.42). Parks 
also staffs the Urban Forestry Commission and runs the Heritage Tree Program, a Neighborhood 
Tree Liaison Program, and various education and planning efforts. Title 16 and Title 17 also include 
tree regulation in the public right-of-way and associated with other public infrastructure (sewer 
and stormwater systems). The City is considering a new rule to regulate private street trees by 
administrative rule (under Chapter 24). The Bureau of Development Services regulates tree 
preservation, protection and mitigation associated with land divisions and with all development in 
special overlay zones and plan districts. 
In recent years there has been considerable confusion about Portland's tree regulations and 
concern about regulatory gaps, loopholes, adequacy of mitigation, inspections and enforcement. 
The City of Portland is in the midst of a comprehensive review and evaluation of tree regulations 
and their administration and enforcement. The "City-Wide Tree Project" identified a number of 
problems with the existing regulatory structure including regulatory gaps and administrative 
complexity. The project has suggested the need for greater consolidation and consistency and to 
elevate tree preservation and protection in the development review process. 
The City of Portland funds urban forestry and urban forestry-related activities through a variety of 
sources and through different bureaus. The Bureau of Development Services is funded largely 
through permit fees. The Urban Forestry Division is funded largely through the general fund but 
also through grants. Portland Parks also conducts natural area acquisition with funds from bonds 
and system development charges. The Bureau of Environmental Services coordinates Portland's 
22 
Cit)' o f Tigard Urban Fores try Code Rc,·isions I Volume V I 199 
"Grey to Green Initiative" which uses some sewer and stormwater fees to fund natural area 
acquisition and watershed re-vegetation, including tree planting. The Grey-to-Green initiative has a 
goal of planting 83,000 trees over a five-year period at a cost of roughly $14 million. Meeting this 
goal will depend on success in securing federal stimulus funds. As part of that goal the city planted 
some 1,700 street trees through a partnership with Friends of Trees and 144 trees in public parks 
and natural areas. 
In 2007 the City of Portland began the Citywide Tree Project, "a multi-bureau effort to clarify, 
simplify and provide a consistent and effective regulatory framework for trees in the City of 
Portland." Over several months the city has worked with a diverse group of stakeholders to develop 
a series of issue papers describing the city's policies, regulations and administrative processes and 
indentify problems and possible solutions for reform. In February 2009 staff presented a 
preliminary set of policy solutions and regulatory improvements to the planning commission. The 
interbureau project staff is currently preparing a refined set of policy and regulatory changes 
scheduled to go before the planning commission in Fall 2009. These include proposals to: 
Establish a clear, cohesive regulatory framework 
• Establish a single point of contact for the public 
• Pilot a 24-hour response line 
• Create comprehensive consolidated tree/urban forestry title 
• Develop a tree technical manual 
• Create a consistent, equitable tree cutting permit system 
• Clarify and build community understanding of the public and street tree permit system 
• Consolidate permitting functions 
Enhance the urban forest through development and redevelopment 
• Establish flexible development standards to improve tree preservation 
• Provide advanced mitigation credit for proactive tree planting 
• Improve tree preservation, planting and mitigation in land division and other discretionary 
reviews 
• Establish tree planting standards for building permits 
• Better address tree preservation and protection in public works and capital projects 
• Optimize tree preservation and solar energy systems, sign visibility and views 
• Update and clarify in-lieu of planting fees and tree fund 
• Improve implementation, inspections and resolution of violations 
City of Rivergrove 
Rivergrove has no urban forestry-related policy goals in its comprehensive plan but has had an 
ordinance regulating tree removal for over 10 years. The tree ordinance was most recently updated 
in 2004 and regulates trees on private land and in the public right-of-way. City staff are currently in 
the process of be updating the ordinance again. The City of Rivergrove regulates tree removal near 
streams and wetlands consistent with Metro's Title 13 performance standards. 
Ordinance No. 74-2004 requires tree-cutting permits for trees on private land and in the public 
right-of-way with 11.5 inch diameter measured 4.5 from the ground with special provisions for 
retroactive emergency permits. Permits are granted promptly for up to three trees within a 12-
month period on lots located outside a water quality resource area. If located inside a water quality 
resource area the permit requires the approval of the planning commission at one of its meetings. 
City of Sherwood 
Sherwood has had urban tree regulations in place for the last 17 years, located within their Zoning 
and Community Development Code and implemented new tree regulations in 2007 (16.142) . The 
city has had Tree City USA designation for four years and has an established urban tree board or 
23 
City of 'J'igarJ Urban l;orc>try CoJc Rc,·i>ion> I \ 'olumc \' I 200 
committee. The main goal of the city's tree preservation standards is to minimize the removal of 
trees and woodlands within the city. Sherwood does not have an adopted urban forestry plan. 
The code regulates the size of regulated trees depending on species differently for tree removal and 
protection requirements within the development process and outside of it. For planned unit 
developments, site review and subdivision, the code protects Douglas fir, ponderosa pine, red 
cedar, white oak, big leaf maple and American chestnuts that are ten inches or greater, while all 
other species are regulated if they are five inches or greater. The code only allows tree removal 
during development within areas that are needed to build utilities and infrastructure, streets and 
grading necessary for development in PUD and subdivisions. 
Outside of the development process, regulated deciduous trees are those that are 10" or greater and 
coniferous trees that are 20" or greater. Landowners are allowed to remove five trees per year, not 
exceeding 100" dbh total. However, there is no permit system in place. Instead, the landowner must 
report to the planning department at least 48 hours before tree removal. If landowners wish to 
remove more than the maximum allowance then they must apply for a site plan review at a cost of 
$200. 
Sherwood's natural resource overlay zones define minimum disturbance standards for resource 
protection, but do not have any regulations that target tree conservation specifically and regulated 
areas are exceeded by Clean Water Service's vegetated corridor standards. Sherwood does not 
regulate any heritage or historic trees. 
City of Tigard 
Tigard has had Tree City USA designation since 2000 and an established tree board for the past 
seven years. Tigard implemented it first tree ordinances and regulations 25 years ago. Those tree 
regulations governed the removal of all trees on undeveloped land, developed commercial and 
industrial land, and public land. However, changes to the tree ordinance in 1997 now allow the 
removal of any tree as long as its removal is mitigated. Currently, tree removal permits are 
processed by means of a Type I procedure. 
Tigard regulates trees on both public and private property. Regulated trees during development are 
defined as any tree ~ 6 inches db h. Trees that require a removal permit include street trees, trees 
on city property, trees that were planted as a condition of development approval, trees in sensitive 
lands areas, trees on developing properties, trees that are restricted on the deed of a property, and 
heritage trees. Removal is defined as the cutting or removing of 50 percent or more of a crown, 
trunk or root system of a tree (Section 9.06.020). 
In fiscal year 2007/2008, Tigard spent approximately $200,000 on urban forestry-related activities. 
Funding comes from general fund allocations (mostly property taxes), development fees and grants. 
Additional funding comes for urban forestry-related activities come from Clean Water Services 
stormwater service fees. Through a partnership with Clean Water Services, the City of Tigard is 
conducting stream restoration and enhancement projects that will result in the planting of 
approximately 100,000 native trees from 2001 to 2011. Also, the city's public works department 
annually plants approximately 250 new or replacement trees on public lands, distributes street 
trees each year to private property owners through the Street Tree Program, and plants 25 trees in 
celebration of Arbor Day. 
Tigard is currently developing an Urban Forestry Master Plan, scheduled for completion in 
November 2009. This will include revisions to Tigard's tree and landscaping ordinances and the 
development of a tree grove protection program. 
City of'l'iganl Urban Forestry Code Re,·isions I Volume V I 201 
24 
City of Troutdale 
Troutdale has had tree regulations that apply both during development and outside of the 
development review process for at least eight years. The city has had Tree City USA status since 
2000 with its parks advisory committee acting as the city's tree board. Troutdale's tree ordinance is 
in the city's municipal code. It addresses the planting and maintenance of street trees, heritage 
trees and the removal of trees on undeveloped properties. 
The city's street tree fund is restricted to the planting, maintenance and removal of street trees. 
Resources come from street tree fees during development, donations, grants or penalties. The city 
has also created a manual that includes a list of approved street trees, prohibited street trees and 
planting and pruning guidelines. It also has a street tree plan to regulate the maintenance and tree 
removal of street trees. 
Troutdale regulates trees that are ~ 6 inches in diameter. Tree removal regulations can be found 
within section 13.10.270 of the municipal code. There is no permit requirement for tree removal in 
developed property, only for undeveloped or underdeveloped properties. These include any vacant 
platted subdivision lots or partition parcels, or any developed properties able to be partitioned into 
two or more lots. A tree removal permit can be obtained in conjunction with a land use permit or 
under a Type II permit when not in concordance with a land use permit. The code allows for the 
removal of hazardous, dead or diseased trees within city limits, within all land uses. 
City of Tualatin 
Tualatin has had Tree City USA status since 1987 and has had a tree preservation ordinance and 
urban tree committee in place since 1979. The city council adopted the existing ordinance in 2001 
with an urban forestry management plan that focuses on street trees. Tualatin has won several 
awards for its urban forestry activities over the last 25 years. 
Tualatin regulates removal of trees greater than eight inches in diameter during development 
review and outside the development process. However, various exemptions allow removal of trees 
greater than eight inches outside these permit processes. The city of Tualatin does not require 
mitigation when regulated trees are removed unless those trees were designated for preservation 
and were lost or damaged during construction. Tualatin is working on developing new regulations 
that would require mitigation. Some tree preservation and tree protection apply in Tualatin 's 
natural resource protection overlay but these areas are mostly covered by Clean Water Service's 
vegetated corridor standards. Tualatin regulates street trees and requires the planting as a 
condition of approving development. The city also pays for some street tree planting. Additional 
tree planting requirements are applied in parking lots and as part of landscaping requirements. 
Over the years, urban forestry activities in Tualatin have been fu nded via a combination of property 
taxes, development fees, general fund allocations, grants and the city's road fund. In the 2007-2008 
fiscal year Tualatin spent $215,465 on urban forestry-related activities. 
Tualatin officials are currently considering a number of potential changes to the city's tree codes 
including reducing exemptions that allow tree removal outside the permit process, the size of 
regulated trees, and requiring some mitigation of tree removal. There is also discussion of raising 
additional funds for urban forestry activities by establishing a tree bank fund for in-lieu mitigation 
and/or raising funds through a street utility fee. 
City of Vancouver 
Vancouver first established a street tree ordinance in 1963. The city established an Urban Forestry 
Commission in 1987 and achieved Tree City USA status with updated policies and regulations 
relating to urban forestry. Vancouver adopted its existing policies and regulations governing 
private tree removal and mitigation in 1997. In 2006, Vancouver adopted a revised street tree 
ordinance to reflect national standards and best management practices. 
25 
City of Tigard Urban l ;or~stry Code Rc,·isions I \ 'olum~ \ ' I 202 
In 2007 Vancouver adopted its current Urban Forest Management Plan. The plan included a 2003 
urban forest canopy inventory that established a baseline of canopy cover by land-use type and 
established goals for expanding urban forest cover over time. Although the plan specifies no target 
date for achieving canopy cover goals, the inventory will be revisited in 2011 to evaluate whether 
existing policies and programs are adequate. 
Regulations governing tree protection, removal and mitigation include: 
• The Tree Conservation Ordinance, VMC 20.770, established in 1997 and amended in 2004 to 
regulate trees on private land including Vancouver's Heritage Tree program. VMC 20.770 
primarily applies when a property is developed or to trees preserved or planted as a condition 
of past development. 
• Street Tree Ordinance, Vancouver Municipal Code (VMC) 12.04, established in 1963 and 
amended in 2006 to regulate trees in the public right-of-way. 
• Critical Areas Ordinance, VMC 20.740, adopted in 2005 to protect environmentally sensitive or 
natural hazard lands. 
• Landscaping Code, VMC 20.925, requiring tree planting. 
The existing suite of ordinances aim to protect and enhance a variety of public values associated 
with urban forests including air and water quality, wildlife habitat, public health and safety, 
property values, economic development and implementation of state and federal law. Vancouver 
requires the planting of street and parking lot trees as a condition of development. 
Vancouver's Urban Forestry division's budget for the 2007-2008 fiscal year totaled 950,000. The 
division has three full time employees including a city forester, funds tree planting in the public 
right-of-way and on public and private land, and has a number of partnerships with private and 
private-non-profit entities to promote stewardship and expansion of Vancouver's urban forest. 
Funding from urban forestry comes from stormwater fees, the city's general fund and 
compensatory mitigation via a city tree fund. 
Vancouver has no specific plans for making policy changes. However an assessment of urban forest 
canopy cover in 2011 for the entire city will aid in evaluating progress in achieving the goals and 
targets established in the urban forestry management plan. If goals are not being achieved then the 
policies and regulations could be revisited and revised. This could include revisiting the required 
minimum tree density standard. 
Washington County, urban unincorporated 
Washington County limited policies and regulations relating to tree preservation or mitigation 
outside "Significant Natural Resources Areas" mapped and regulated as part of the county's 
acknowledged GoalS program or floodplain and natural drainage hazard areas. Policy 10.h for 
"Biological Resources and Natural Areas" of the comprehensive plan circumscribes tree regulations 
to significant natural areas by committing the county to "Develop tree conservation standards to 
regulate the removal of or damage to trees and vegetation in identified Significant Natural Areas 
within the unincorporated urban area, in order to retain the wooded character and habitat of urban 
forested lands." Section 421 references the retention of"large trees" in flood areas. Section 422 
governs tree removal associated with Significant Natural Resource Areas. These regulations have 
been in place since 1983. In addition, Section 407 for Landscape Design of the Community 
Development Code has standards for tree removal but not for tree preservation. Section 407 also 
contains planting standards associated with development, including street trees. Some community 
plans have additional tree protections for specific sites; however, all but community plan 
subordinates tree retention to "development of the site at the planned density." Section 404 has 
specific tree-related standards for planned developments. No mitigation of tree removal is required. 
26 
City of Tigard Urban Forestry Code Re,·isions I Volume V I 203 
No permit is required to cut trees outside the development review process unless the site is 
identified as a Goal 5 resource on the applicable community plan. Washington County has no official 
sanctioned tree committee, board, or commission. The county does not have an urban forestry 
management plan. 
Discussions with planning staff and citizens in Washington County reveal that tree removal is often 
deemed unavoidable because of zoned densities. This widespread view may limit more innovative 
designs. Section 207-5.1 of the CDC specifies that conditions on approved development "shall not 
restrict densities to less than that authorized by the development standards of this Code." This 
provision is often invoked as the reason for not preserving more trees. However there is also some 
disagreement as to whether staff can or does use its full discretion to preserve trees through 
clustering or design modification. The widespread view that tree preservation is impractical or 
unachievable at planned densities may dissuade staff from using their discretionary authority to 
preserve trees. In sum, both a lack of specific standards for tree preservation and the presumption 
that trees cannot be accommodated at zoned densities result in little tree preservation in urban 
unincorporated Washington County. 
The Joint-CPO Tree Code Group formed in the summer of 2007 to explore policy and code changes 
and stem the accelerated loss of trees in urban unincorporated Washington County. CPO 
representatives and interested citizens worked together to research what policies and development 
codes other counties and cities have implemented to address tree preservation and increase urban 
forest canopy. The Joint-CPO Tree Code Group produced an executive summary and research report 
in Spring 2009 that was submitted to the Washington County Board of Commissioners. The group 
has requested that development of urban forestry policies be included on the county's 2009 work 
program as a Tier 1 (priority) item. The county commissioners did not include the request in the 
2009 work program but they will consider it for future work plans. For more information on the 
Joint-CPO Tree Code Group see: http://www.washcotreegroup.org /. 
City of West Linn 
West Linn has had Tree City USA status for over a decade. West Linn has no explicit urban forestry-
related policy goals, beyond those outlined in the purpose of its community tree ordinance No. 
1542. The city council adopted these regulations into Sections 8.500-8.750 of the municipal code in 
2006 and revised them in 2008 to regulate tree removal on private property and in the public right-
of-way when development is not proposed or in instances where tree removal is proposed after a 
development application for a site has been approved. The West Linn Development Code contains 
Section 54 Landscaping and Section 55 Design Review that also regulate removal and planting 
when development is proposed. 
West Linn funds urban forestry through development permits and money from the city's general 
fund. These funds amounted to $100,000 in the 2007/2008 fiscal year. Staff in planning, parks, and 
public works all have responsibilities related to urban tree or forestry. West Linn has a city arborist 
who works for the parks department but coordinates with planning and public works. West Linn 
has no urban forestry management plan, tree committee or urban forestry commission. Tree 
removal, especially in environmentally sensitive areas, has been a controversial issue in West Linn. 
No major changes are planned to the tree codes. West Linn staff is planning some minor changes to 
the municipal code to close loopholes and tighten up some definitions and is also considering 
revisions to Section 28 for Willamette and Tualatin River protection. 
City of Wilsonville 
Wilsonville has had Tree City USA designation since 1997. In part due to strong political leadership 
and community support, the city has put a high priority on conservation of trees, vegetation and 
natural areas as integral parts of the city's urban form and quality of life. Since 1997 Wilsonville has 
27 
Citr or Tiga rd Urban Forestry Code Rc,·isions I \ 'o lumc \ ' I 204 
received the Tree City USA Growth Award for its progress in education, partnerships, land-use 
planning coordination, planning and management and wildlife habitat conservation. 
Wilsonville's comprehensive plan and development code includes urban tree and forestry-related 
policy goals. Section 4.600 of the development code requires a permit whether or not development 
is proposed. However, approval to remove up to three trees within a 12-month period is granted if 
the trees proposed for removal are not in a zoned natural resource area, are not street or Heritage 
trees, and were not required to be retained as a condition of past development. Provisions allow for 
the removal of trees that are hazardous, diseased, dead or damaged. The city applies discretionary 
standards including a least impact alternative analysis for situations proposing to remove more 
than four trees and where development is proposed. Decisions are the discretion of the 
development director and can be appealed to the development review board and the city council. 
Wilsonville requires mitigation of most regulated trees. In addition to Section 4.6000, Wilsonville 
regulates tree removal in the public right-of-way, through a heritage tree program and in its 
significant resource overlay zone (Section 4.139.00) and Willamette River Greenway overlay zone 
(Section 4.600.30) 
Wilsonville funds urban forestry through development permits, grants, general fund allocations, a 
local improvement district and a tree mitigation fund. These funds amounted to $220,000 in fiscal 
year 2007/2008 and funded three positions engaged in urban forestry-related planning, permitting 
and programming including two certified arborists. Staff in planning, parks and public works all 
have responsibilities related to urban tree or forestry. Wilsonville has no urban forestry 
management plan but does have an established tree board. 
City of Wood Village 
Apart from some landscaping standards that require some street tree planting and some tree 
planting and vegetation maintenance in one city park (funded by general funds), Wood Village has 
no policies or programs related to urban forestry. 
Wood Village regulates tree removal near streams and wetlands consistent with Metro's Title 13 
performance standards. Riparian transition areas are 50' from top of bank and extending up to 200 
feet where adjacent slopes are greater than 25 percent. As of May 2009, Wood Village had yet to 
substantially comply with Metro Title 13 for water quality and regionally significant fish and 
wildlife habitat. 
28 
City of Tigard Urban Forestry Code Re,·isions I Volume V I 205 

Urban Forestry Code Revisions 
Urban Forestry Master Plan 
City of Tigard Urban Forestry Code Rc,·isions I Volume \' I 207 



I 
City of Tigard 
Urban Forestry Master Plan 
ACKNOWLEDGEMENTS 
Tigard City Council 
Urban Forestry 
Master Plan 
Citizen Advisory Committee 
City of Tigard 
Stakeholder Participants 
Mayor Craig Dirksen, Council President 
Nick Wilson, Councilor 
Gretchen Buehner, Councilor 
Marland H enderson, Councilor 
Sydney Webb, Councilor 
Matt Clemo 
Janet Gillis 
Morgan H olen 
Tony Tycer 
Craig Prosser, City Manager 
Mort E ttelstein 
Phil Hickey 
D ennis Sizemore 
David Walsh 
Ron Bunch, Community D evelopment Director 
Brian Rager, Assistant Public Works Director 
Dick Bewersdorff, Current Planning Manager 
D arren Wyss, Senior Planner 
Todd Prager Associate Planner/ Arborist 
Marissa D aniels, Associate Planner 
John Floyd, Associate Planner 
N athan Shaub, G IS Analys t 
Patty Lunsford, Planning Assistant 
Sam Tilley, Intern 
Chad Burns, Portland General E lectric 
Alan D eHarpport, Home Builder's Association of Metropolitan Portland 
Maryann Escriva, Tigard Tualatin School District 
Terrance Flanagan, Pacific Northwest Chapter of the 
International Society of Arboriculture 
Peter G uillozet, Clean Water Services 
Troy Mears, Oregon Chapter of the American Society of 
Landscape Architects 
E rnie Platt, Home Builder's Association of Metropolitan Portland 
Steve Schalk, Oregon D epartment of Transportation 
Tigard Tree Board Members (2009) 
Brian Wegener, Tualatin Riverkeepers 
Phil Wentz, Tigard Tualatin School District 
------------------------------~ ..... 
City o f Tigard Urban Fores try Code Re,·isions I Volume V I 211 
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City of Tigard I Urban Forestry Master Plan 
Table of Contents 
Executive Summary 1 
Implementation Matrix 2 
Basis for Decision Making 9 
Chapter 1: Development Regulations and Mitigation Requirements 11 
Chapter 2: Landscaping Requirements 13 
Chapter 3: Tree Grove Protection 15 
Chapter 4: Hazard Trees 19 
Chapter 5: Urban Forestry Program Management 21 
Chapter 6: Stewardship 23 
Glossary 29 
APPENDICES 
Appendix A: Urban Forestry Survey Results a1 
Appendix B: Canopy Analysis a16 
Appendix C: Stakeholder Interview Notes a24 
Appendix D: City of Tigard, Internal Coordination Meeting Notes a39 
Appendix E: Urban Forest Section of the Comprehensive Plan a46 
Appendix F: Tigard Urban Forestry Historical Timeline a55 
Appendix G: Review of Current Federal/State/ Regional 
Urban Forestry Policy Framework a56 
Appendix H: Review of Current City of Tigard 
Urban Forestry Policy Framework a63 
Appendix 1: Resolution No. 09-69- A Resolution Accepting 
the City of Tigard's Urban Forestry Master Plan a71 
-------------------------------..... 
City of Tigard Urban Forestry Code Re,·isions I Volume V I 21.3 
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'' Tigard's urban forest is valued 
and protected by City residents 
as a thriving interconnected 
ecosystem managed to improve 
quality of life, increase community 
identity, and maximize aesthetic, 
economic, and ecological benefits. 
'' 
City of Tigard I Urban Forestry Master Plan 
Executive Summary 
T his Urban Forestry Master Plan (UFMP) sets a course of action for the 
City of T igard's urban forestry program from the time of its acceptance 
by Council until the year 2016. T he Plan has been developed through a 
public process involving community outreach and surveys, urban forestry 
stakeholder interviews, departmental coordination meetings, and review 
of current City policies and programs. Based on the information received 
throughout this process, the UFMP Citizen Advisory Committee (CAC) 
recommends the following implementation goals: 
1. Revise Tigard's tree code (Chapter 18.790, includes development 
regulations and mitigation). 
2. Revise Tigard's landscaping code (includes street trees, parking lot 
trees, and other required landscape trees) . 
3. D evelop a tree grove protection program . 
4. Develop a hazard tree identification and abatement program. 
5. Improve the management of the City's urban forestry program . 
6. D evelop an urban fores t stewardship program. 
It is further recommended that the achievement of the above 
implementation goals occur through a series of sub-goals and 
action measures which are outlined in the implementation matrix. 
Implementation goals, sub-goals, and action measures are intended to 
frame future urban forestry code and program development and set a 
timeline for bo th. Tigard 's Tree Board will be charged with overseeing the 
implementation of the UFMP as part of their annual work plan. 
-------------------------------..... 
Ciry of Tigard Urban Forestry Code Rc,·isions I Volume V I 215 
Urban Forestry Master Plan I City of Tigard 
Implementation Matrix 
T he following implementation matrix contains all six UFMP implementa-
tion goals (highlighted in orange), their associated sub-goals (e.g. 1.1 , 1.2, 
1.3 ... ), and a series o f action measures with the necessary level o f detail 
needed to implement the goals and sub-goals. For each action measure 
the lead City division, applicable Comprehensive Plan policies, staff and 
financial resources required, and implementation schedule are included. 
T hrough implementa tion of the goals, sub-goals, and action measures 
in this Plan, progress will be made towards the adopted vision o f the 
UFMP CAC: 
Urban Forestry 
Master Plan ~ 
'' Tigard's urban forest is valued and protected by City residents 
as a thriving interconnected ecosystem managed to improve 
quality of life, increase community identity, and maximize 
aesthetic, economic, and ecological benefits.'' 
..... ~-------------------------------
City of Tiga rd Urban J.'orc> try Code RC\·i>iom I \'olumc \ ' I 21(, 
City of Tigard I Urban Forestry Master Plan 
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1. Revise Tigard's tree code {Chapter 18.790, includes development regulations and mitigation). 
1.1 Revise tree code to allow for more flexibility and ensure a qualitative approach to tree preservation. 
a. Determine the most appropriate placement for Long Range 
future tree code provisions within the Tigard Planning 
Development and Municipal Code chapters. 
b. Modify code to focus less on mitigation and Long Range 
more on preservation of long-lived evergreen and Planning 
broad-leaf deciduous tree species, native and 
indigenous trees, and other trees identified as of 
high importance. 
c. Require private arborists to be involved in the Long Range 
development process from site planning through Planning 
landscape installation. 
d. Develop and implement regulations, standards, Long Range 
and incentives for transferring density and seeking Planning 
variances and adjustments to preserve trees 
identified as being of high importance. 
e. Provide incentives for preserving smaller Long Range 
diameter trees that have a higher ability to Planning 
withstand development impacts. 
f. Ensure invasive trees are exempt from Long Range 
preservation requirements through the adoption Planning 
of an inclusive invasive species list. 
g. Develop standards and procedures for tree code Long Range 
enforcement. Planning 
h. Develop procedures detailing when and how Current 
protected trees will be inventoried and permit Planning 
activities tracked. 
i. Develop and maintain, as part of the City's GIS and Current 
permit systems, a publicly accessible inventory of Planning 
protected trees. 
j. Create a tree manual with drawings and Current 
specifications for development related tree Planning 
inventory and protection standards, and 
preferred species/tree types for preservation. 
-~'-- ---------------
* Low = 0-8 hours of staff time 
** $ = <$ 1,000 
* Med. = 8- 40 hours of staff time 
** $$ = $1,000-$10,000 
2.2.1 ' 2.2.2, 2.3.1 ' Low $ 
2.3.2, 2.3.3, 2.3.6, 
2.3.7, 2.3.9, 2.3.10, 
2.3. 11 
2.2.1 ' 2.2.2, 2.2.9, High $$ 
2.3.1 ' 2.3.2 , 2.3.3, 
2.3.4, 2.3.6, 2.3.7, 
2.3.9, 2.3.11 
2.2.1, 2.3.1, 2.3.3, Low $ 
2.3.6, 2.3.7, 2.3.8, 
2.3.9 
2.2.1 ' 2.2.2, 2.3.1 ' High $$ 
2.3.3, 2.3.6, 2.3.8, 
2.3.9, 2.3.11 
2.2.1 ' 2.2.2, 2.2.9, Low $ 
2.3.1 ' 2.3.2, 2.3.3, 
2.3.4, 2.3.6, 2.3.7, 
2.3.9, 2.3. 11 
2.2.1 , 2.2.2, 2.2.7, Low $ 
2.2.8, 2.2.9, 2.3.1 , 
2.3.7, 2.3.8, 2.3.11 
2.2.1 , 2.2.2, 2.2.3, Med. $$ 
2.2.6, 2.3.1 , 2.3.8, 
2.3.9, 2.3.11 
2.2.1 Med. $$ 
2.2.1 Med. $$ 
2.2.1 ' 2.2.2, 2.2.8, High $$$ 
2.2.9, 2.3.1, 2.3.2, 
2.3.3, 2.3.6, 2.3.7, 
2.3.8, 2.3.9 
* High = over 40 hours of staff time 
** $$$ = $10,000-$50,000 
2010 2011 
2010 20II 
2010 2011 
2010 20II 
2010 2011 
2010 2011 
2010 2011 
2011 2012 
2011 Ongoing 
2010 2011 
** $$$$ = >$ 50,000 
-------------------------------------...... 
City of Tigard Urban Fores try Code ReYisions I Volume V I 217 
Urban Forestry Master Plan I City of Tigard 
c ... 
Ill = ~ c a: Ill Ill u 0 a..!!! +' I. ... 
, :!a "' :I Ill ... Implementation Goals E~ >.0 • +' >.Ill Ill > +' Ill -~ 0 Gl ·- 0 0 ·- Gl 
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1.2 Revise tree code so that standards do not solely impact those property owners with trees. 
a. 1 Develop canopy cover or tree density standards Long Range 2.2. 1, 2.2.2, 2.2.4, I High I $$ 
for aU lots to be met by either preserving existing Planning 2.2.9, 2.3.1, 2.3.2, 
trees, or planting new trees. 2.3.6, 2.3.7, 2.3 .9, 
2.3.11 
b. I Investigate possible funding mechanjsms I Current 12.2 .1, 2.2.2 , 2.2 .7, I High I $$ 
to help support an ongoing tree and urban Planning 2.3.8 
forest enhancement program. 
2.1 Revise street tree planting, mruntenance, and removal requirements. 
a. Revise parking lot design requirements to Current 
incorporate stormwater management techniques Planning 
and methods that support increased tree canopy. 
b. Revise Tigard Municipal Code to establish a Long Range 
permit system for planting, removal , and Planning 
replacement of required trees. 
c. Incentivize the use, retention, and replacement Current 
of long uved evergreen and broad-leaf deciduous Planning 
tree species, native and indigenous trees, and 
other trees identified as of hjgh importance. 
d. Allow required landscape trees to count towards Long Range 
mitigation, canopy cover, and/or tree density Planning 
standards. 
e. Require landscape architects to develop Long Range 
landscape plans for projects of a certrun type Planning 
and/or size. 
f. Create a design and mruntenance manual with Current 
drawings and specifications for species selection , Planning 
planting, and maintenance. 
g. Clarify jurisdictional requirements along ODOT Current 
right-of-ways (mghway 99W, mghway 217, and Planning 
Interstate 5). 
-- ---
* Low = 0-8 hours of staff time 
** $ = <$ 1,000 
* Med. = 8-40 hours of staff time 
** $$ = $1,000-$10,000 
2.2.1 , 2.2.2, 2.2.4, Med. $$ 
2.2.7, 2.2.8, 2.2.10, 
2.3.5, 2.3.7, 2.3.8, 
2.3.11 
2.2 .1, 2.2.2, 2.2 .4, Me d. $$ 
2.2.5 , 2.2.6, 2.2 .8, 
2.2.9, 2.2.1 0, 2.3.5 , 
2.3 .7, 2.3.10, 2.3.11 
2.2.1, 2.2.2, 2.2.4, Med. $$ 
2.2 .5, 2.2.6, 2.2.7, 
2.2.8, 2.2.9, 2.2.1 0, 
2.3.1 , 2.3.5, 2.3.7, 
2.3.8, 2.3.11 
2.2.1 , 2.2.2, 2.2.4, Low $ 
2.2.6, 2.2.7, 2.2.8, 
2.2.9, 2.2 .10, 2.3.5 
2.2.1, 2.2 .2, 2.2.7, Low $ 
2.2.10, 2.3.5, 2.3.7, 
2.3.11 
2.2.1, 2.2.2, 2.2.4, High $$$ 
2.2.5, 2.2.6, 2.2.7, 
2.2.8, 2.2 .9, 2.2.10, 
2.3.5 , 2.3.7, 2.3.8, 
2.3.11 
2.2.1 , 2.2 .2, 2.2.4, Low $ 
2.2.5, 2.2.6, 2.2.7, 
2.2.8, 2.3.5 , 2.3.8 
* High = over 40 hours of staff time 
** $$$ = $10,000-$50,000 
c I 
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2011 I 2012 
2010 2011 
2010 2011 
2010 2011 
2010 2011 
2010 2011 
2010 2011 
2010 2011 
** $$$$ = >$ 50,000 
- ....------------------
Cil"y of Tigard Urban Forestry Code RtYisions I \ 'olumc \ ' I 21 8 
City of Tigard I Urban Forestry Master Plan 
Implementation Goals 
h. I Do not require new technologies that are cost 
prohibitive. 
c 
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2.2 Develop an inventory of tree plantings, removals, and replacements. 
a. 1 Develop procedures for when and how trees will 
be inventoried and permit activities tracked. 
Current 
Planning 
b. I Develop and maintain, as part of the City's GIS I Current 
and pennit systems, a publicly accessible inventory Planning 
of tree plantings and permitted removals. 
3.1 Focus on preserving large groves of native trees. 
a. Establish standards and procedures for identifying Long Range 
and inventorying large groves of native trees. Planning 
b. Develop preservation and maintenance standards Long Range 
and procedures for tree groves identified for Planning 
protection while allowing for the full develop-
ment of property under current zoning. 
2.2.1 
2.2.1 
2.2.1 ' 2.2.2, 2.2 .3, 
2.2.6, 2.2.7, 2.3 .1, 
2.3.2, 2.3.8, 2.3.9, 
2.3.11 
2.2.1 ' 2.2.2, 2.2.3, 
2.2.4, 2.2.6, 2.2. 7, 
2.2.8, 2.2.9, 2.3.1 ' 
2.3.2 , 2.3.3, 2.3.5, 
2.3.6, 2.3.7, 2.3.8, 
2.3.9, 2.3.11 
i< 
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Low $ 2010 
Med. $$ 2011 
Med. I $$ 2011 
High $$$$ 2010 
High $$$ 2011 
L___ 
3.2 Develop a flexible and incentive based grove preservation program that meets the needs of affected property owners. 
a. 1 Reach out to property owners with identified tree 
groves early in the process to allow them ample 
opportunity to participate in the development of 
regulations. 
Long Range I 2.3.8, 2.3. 11 
Range 
b. I Ensure any future tree grove regulations have Long Range 2.2.1 , 2.2.2, 2.2.4, 
flexibility and incentives built in. Planning 2.3.6, 2.3.8, 2.3.11 
4 .I Establish City storm and hazard tree response protocols. 
a. Prior to land acquisition conduct a tree hazard Parks 2.2.1 ' 2.2.2, 2.3.4, 
assessment. 2.3.8 
b. Develop and implement a formal emergency Streets 2.2.1 ' 2.2.2, 2.3 .4, 
response system for tree hazards on City streets. 2.3.8 
c. Develop and implement a formal emergency Parks 2.2.1 , 2.2.2, 2.3.4, 
response system for tree hazards in City parks/ 2.3.8 
greenspaces. 
Med. $$ 2010 
Med. $$ 2011 
Med. $$ 2010 
Low $ 2010 
Low $ 2010 
--------- - - - - -- -
Cll r:: 
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Ongoing 
2012 
Ongoing 
2011 
2012 
2012 
2012 
Ongoing 
Ongoing 
Ongoing 
- ---------- ----
* Low = 0-8 hours of staff time 
** $ = <$1,000 
* Med. = 8-40 hours of staff time 
** $$ = $1,000-$10,000 
* High = over 40 hours of staff time 
** $$$ = $10,000-$50,000 ** $$$$ = >$50,000 
-----------------------------------------...... 
City of Tigard Urban Fore,try Code ReYisions I Volume V I 219 
Urban Forestry Master Plan I City of Tigard 
c ... 
10 ~ ;: 
c ii: Ill 10 u 0 o..!!! .... ... ... 
"'0 :!1! VI ::J Ill ... Implementation Goals E~ >.0 ~ .... >.Ill 10 > .... Ill -~ 0 Cll ·- 0 0 ·- Cll 
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4.2 EstabUsh a City program to fac ilitate tree hazard identification and abatement on private property. 
a. 1 Revise Tigard Municipal Code to grant authority Long Range 
to the City to become involved in private Planning 
property tree hazards. 
b. I Develop and maintain criteria for what Current 
constitutes a tree hazard using the Tree Risk Planning 
Assessment methodology developed by the 
PNWISA. 
c. 1 Develop and maintain criteria for hazard Current 
abatement and risk mHigation . Planning 
d. I Develop procedures for mediating disputes Long Range 
including assigning responsibiUty. Planning 
e. 1 Make information about hazard tree Current 
indentification and abatement program available Planning 
to the public. 
e management of the City' 
5.1 Begin developing a tree and urban forest inventory. 
a. Develop procedures for when and how Current 
protected trees, tree groves, street trees, Planning 
heritage trees, and required landscape trees will 
be inventoried and permit activities tracked. 
b. Develop and maintain, as part of the City's GIS and Current 
permit systems, a pubUcly accessible inventory Planning 
of protected trees, tree groves, street trees, 
heritage trees, and required landscape trees. 
c. Develop and maintain, as part of the City's GIS Current 
system, a pubUcly accessible inventory of sites Plannjng 
where urban forestry fees are being utilized. 
Link sites with the City's accounting system so 
detailed analyses of urban forestry expenditures 
can be obtained. 
5.2 Improve management of City owned trees and forests . 
a. Create and route a budget sheet to appropriate Parks 
divisions prior to park and greenspace 
acquisitions so anticipated costs and benefits 
can be identified and evaluated. 
-----------------------
* Low = 0- 8 hours of staff time 
** $ = <$ 1,000 
* Med. = 8-40 hours of staff time 
** $$ = $1,000-$10,000 
. 
2.2 .1' 2.3 .4, 2.3.8, $$ 
2.3.11 
2.2.1 ' 2.2.2 $$ 
I I 
2.2.1 , 2.2.2 , 2.3.4, I Med. I $$ 
2.3. 11 
2.3.4, 2.3.11 I High I $$$ 
12.3.4, 2.3.8 I Med. I $$ 
2.2.1 Med. $$ 
2.2.1 Me d. $$ 
2.2.1 ' 2.2.2, 2.2. 7 Med. $$ 
------ ---------
2.2.1 , 2.2.2, 2.2. 7, Low $ 
2.3.4 
* High = over 40 hours of staff time 
** $$$ = $10,000-$50,000 
I c Cll c 
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I 2010 I 2011 
I 2010 I 2011 
I 2010 I 2011 
I 2010 I 2011 
I 20 10 I 2011 
2011 2012 
2011 Ongoing 
2011 Ongoing 
2010 2011 
** $$$$ = >$ 50,000 
....---------------------------------
City of Tigard Urban I 'orcs try Code Rc,-isions I \' olumc \ ' I 220 
r::: 
0 
"'0 :!1! Implementation Goals 111 > Cll ·-
...JO 
b. I Create a greenspace coordinator position to I Parks 
manage City owned natural areas and develop a 
proactive hazard tree identification and 
abatement program for those areas. 
c. 1 Develop a written set of urban forestry Current 
standards and specifications for City projects. Planning 
d. I Identify and secure long term funding sources for Current 
urban forestry projects as mitigation funds decline. Planning 
e. 1 Designate City Arborist as lead coordinator for Current 
implementation of the Urban Forestry Master Plan. Planning 
6. Develop an urban forestry stewardship program. 
6.1 Develop and provide urban forestry outreach materials. 
a. Provide Tigard citizens with pertinent urban Current 
forestry outreach information such as workshops, Planning 
flyers, online tools, "ask the arborist" service, etc. 
b. Maintain a list of invasive trees and other plants, Current 
discourage their sale and propagation, and Planning 
promote their removal. 
6.2 Fund urban forestry projects for private property owners. 
a. Utilize mitigation and other funding sources for Current 
tree planting and urban forest management on Planning 
public and private property and public 
right-of-way. 
b. Present a cost/benefit study for a leaf pickup Current 
program for Council's consideration. Planning 
6.3 Prevent pre-development clearing of lots. 
a. Develop standards that require tree removal Long Range 
permits prior to the removal of a specified Planning 
number of trees per year. 
* Low = 0-8 hours of staff time 
** $ = <$1 ,000 
* Med. = 8-40 hours of staff time 
** $$ = $1 ,000-$10,000 
City of Tigard I Urban Forestry Master Plan 
r::: i< 
111 ~ ~ 0:: Ill 111 u 
c..~ .... ... i< 
"' :::s Ill i< E~ >.0 ~ .... >.Ill 
.... Ill .~ 0 0 0 
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2.2.1, 2.2.2, 2.2.5, $$ 
2.2.6, 2.2.7, 2.3.1 , 
2.3.3, 2.3 .7, 2.3.9 
1 2.2.1 , 2.2.2, 2.2.7 I Low 1$ 
2.2.2, 2.2 .6, 2.2.11 , $ 
2.3.4, 2.3 .7 
2.2.7, 2.3.8 Med. $$ 
2.2.1 , 2.2.7, 2.2.8, Low $ 
2.2.9, 2.3.8, 2.3.11 
-- ------- - -- -
L ... 
2.2.7, 2.3.8 High $$$ 
2.2 .7, 2.3.8 Low $ 
. . ..... --- ' 
2.2.1, 2.2 .2, 2.2.7, Med. $$ 
2.3.1 ' 2.3.8 
* High = over 40 hours of staff time 
** $$$ = $10,000-$50,000 
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I 2011 I 2012 
I 2014 I 2016 
I 2010 I Ongoing 
2012 2013 
2012 2013 
- - - ----- -- --
2013 2014 
2013 2013 
..... 
2010 2011 
** $$$$ = >$50,000 
--------------------------------------------------------------..... 
City of Tigard Urban Forestry Code Re,·isions I Volume V I 221 
Urban Forestry Master Plan I City of Tigard 
c 
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..JO UD. Ull:: uu m_..., U-..., 
6.4 Regularly update the Urban Forestry Master Plan, set achievable goals, and continually monitor progress. 
a. Strive to achieve no net loss in citywide tree Current 2.2.7, 2.2 .11 , 2.3.8 Low $ 2015 2015 
canopy from 2007- 2015. Planning 
b. Strive to achieve 32% citywide tree canopy by Current 2.2.7, 2.2.11, 2.3.8 Low $ 2027 2027 
2027 Planning 
c. Strive to achieve 40% citywide tree canopy by Current 2.2.7, 2.2.11 , 2.3.8 Low $ 2047 2047 
2047 Planning 
d. Update Urban Forestry Master Plan every 5-7 Current 2.2.1 , 2.2.2 , 2.2.11 , High $$$ 2015 2016 
years. Planning 2.3.1 , 2.3.8 
e. To help inform future Plan updates, collect Current 2.2. 1, 2.2. 7, 2.2.11 High $$ 2014 20 15 
baseline tree inventory data in addition to Planning 
canopy cover data. 
---------
* Low = 0-8 hours of staff time 
** $ = <$ 1,000 
* Med. = 8-40 hours of staff time 
** $$ = $1,000-$10,000 
* High = over 40 hours of staff time 
** $$$ = $10,000-$50,000 ** $$$$ = >$50,000 
- -------------------
Ci ty o r Tiganl Urban l'orcstn· Code Rc,·isions I \' olumc \ ' I 222 
City of Tigard I Urban Forestry Master Plan 
Basis for Decision Making 
The following information was used as the basis for decision making when 
formulating goals, sub-goals, and action measures for the UFMP. 
Urban Forestry Survey 
An independent, scientific telephone survey of 400 randomly selected 
citizens about their attitudes towards existing and potential urban fores try 
policies and programs was completed by Steve Johnson and Associates 
in D ecember of 2008. T he survey was funded in part by a grant from 
the Oregon D epartment of Forestry and the USDA Forest Service. 
T he purpose of the survey was to gain a more detailed understanding 
of community attitudes towards urban forestry issues in Tigard. Exact 
questions and complete results from the survey are included in Appendix A. 
Canopy Analysis 
In cooperation with Metro, Tigard 's tree canopy from 1996 and 2007 was 
identified and mapped using aerial photography. This has allowed for 
easy identification of where the urban forest is increasing, decreasing, 
and remaining the same. It will also allow for continual tracking of 
canopy change in the future as Metro runs the software that can detect 
the presence of tree canopy cover every two years. Using the results, 
management decisions were made such as where preservation and planting 
efforts should be targeted. Full results of the canopy analysis are in 
Appendix B. 
Stakeholder Interviews 
City staff interviewed major community stakeholder groups and 
jurisdictions that regularly contribute to and / or are affected by the 
management of Tigard's urban fores t. T he full stakeholder interview notes 
are included in Appendix C. 
City of Tigard, Internal Coordination Meetings 
The City of Tigard has multiple departments, divisions, boards, and 
committees that administer and implement the City's urban forestry 
------------------------------~ ..... 
City of Tigard Urban Forestry Code Rc,·isions I Volume V I 223 
Urban Forestry Master Plan I City of Tigard 
program. Key City staff members with roles in coordinating and 
implementing Tigard 's urban fores try programs, policies, and codes 
met to discuss urban fores try coordination needs and to identify 
solutions. T he purpose of tllis coordination is to provide for more 
effective administration o f the urban fores try program and to inform 
recommendations made in the UFMP. Full results o f the internal 
coordination meetings can be found in Appendix D. 
Review of Current and Historical Urban Forestry 
Codes, Polices, and Programs 
A thorough review and analysis of urban fores try related laws, codes, 
policies, and programs was undertaken to inform recon1mendations in the 
UFMP. Particular attention was paid to the Urban Forest Section of the 
Comprehensive Plan (Appendix E) which contains the goals, policies, and 
action measures that guide Tigard's urban fores try program. Appendix E 
also provides examples of the social, ecological, and economic benefits of 
urban trees and fores ts. 
Appendix F contains a historical t:imeline relative to urban fores try in 
Tigard. Appendix G contains a review and analys is o f the major Federal, 
State, and Regional policies that provide a framework for Tigard's urban 
fores try program. Appendix His a review and analysis of current urban 
fores try related City codes. 
UFMP CAC 
T he UFMP CAC was comprised o f the Tree Board plus four additional 
residents / business interests at large including two certified arborists, one 
homebuilder, and one resident with expertise in public administration. 
T hey met every o ther month to receive information as it was being 
collected and advised staff on Plan development. 
'' City staff interviewed major 
community stakeholder groups 
and jurisdictions that regularly 
contribute to and/or are affected 
by the management of Tigard's 
urban forest. The full stakeholder 
interview notes are included in 
Appendix C. 
'' 
....-~------------------------------
Ciry of Tigard Urban l'orcstry Code Rc,·isiom I \'olumc \ ' I 224 
City of Tigard I Urban Forestry Master Plan 
CHAPTER 1: 
Development Regulations and 
Mitigation Requirements 
Implementation Goal 1 : 
Revise Tigard's tree code (Chapter 18.790, includes 
development regulations and mitigation}. 
Revising Tigard 's tree code is purposely listed as Goal 1 due to strong 
dissatisfaction with the existing code by those both inside and outside of 
the development community. 
Tigard's existing tree code is located in Chapter 18.790 of the Tigard 
D evelopment Code. T his Code requires certain types of development 
projects to prepare a tree plan and identify trees to be preserved and 
removed during construction. Tree replacement, or mitigation, is required 
on an "inch for inch" basis. T his m eans that if a tree with a trunk that is 
12 inches in diam eter is rem oved, it needs to be replaced with 6, 2-inch 
diameter replacement trees. If a developer chooses not to replant trees, 
then the City requires a " fee-in-lieu payment" to the Tigard Tree Fund at 
the current rate o f $125 per diameter inch (2009) . 
Some o f the criticism of the tree code from stakeholders is that 
the mitigation structure prom otes overplanting, it does not require 
preservation of quality trees, and it encourages the retention of large 
diameter trees that are less likely to survive development impacts. T he 
Home Builder's Association o f Metropolitan Portland (HBAMP) position 
is that the fee-in-lieu of mitigation is excessive and that the tree code does 
not adequately reward the preservation of high quality trees. T he H BAMP 
and other stakeholders agree that the tree code unfairly penalizes those 
property owners with exis ting trees more than those owners without trees. 
For the City, the tree code is also administratively difficult to implement 
because it is challenging to track protected and replacem ent trees in the 
years and decades following development. 
T he previous tree code that went into effect in 1983 was m ore 
preserva tionist than today's code because it required a permit prior to the 
removal of any tree on all undeveloped land, developed commercial and 
industrial land, and public land. In 1997 Tigard's tree code was revised to 
------------------------------~ ..... 
City of Tigard Urban Forestry Code ReYisions I Volume V I 225 
Urban Forestry Master Plan I City of Tigard 
its current form. The code currently allows any or all trees to be removed 
as long as they are replaced. Due in part to dissa tisfaction with the existing 
tree code, the Tigard Tree Board was charged with developing a "City 
Tree Stewardship and Urban Forest E nhancement Program" in 2007. 
Following over a year of work by the Tree Board, a comprehensive plan for 
the urban forest was developed in 2008. The Urban Forest section of the 
Comprehensive Plan (Appendix E) contains two goals to be implemented 
by 22 policies. T he goals and policies in the Comprehensive Plan guide the 
recommendations made in this Plan. 
Willie many are unhappy with the current tree code, the UFMP community 
survey confirmed Tigard residents want the City to require some trees are 
preserved and new trees planted during development (~ 88% support) . 
.A majority (~ 57%) of respondents say they support new development 
regulations even if they limit the size and extent of potential buildings 
or profits. Approximately 32% of respondents oppose tree regulations 
limiting development. (See Figure 1 at right) . 
Protecting Tigard's urban fores t on developable land must be balanced with 
State, Metro, and City planning goals and regulations which favor density 
in urban areas. Specifically, development regulations must be clear and 
objective, and not discourage needed housing through unreasonable cost 
or delay according to State law. Only 7% of Tigard's land area and 12% of 
its citywide tree canopy are on developable property so a comprehensive 
urban forestry code and program must address areas outside of 
development. 
Direction received from the community and stakeholders regarding tree 
code revisions have been folded into several sub-goals and implementation 
measures. Major recommendations include: 
• D etermining the mos t appropriate placement for future tree code 
provisions to improve administration and address situations outside 
development; 
• Less focus on mitiga tion and more on preserving high quality trees; 
• Revising tree preservation incentives so that they are more attractive 
to developers; and 
• Not unfairly penalizing those property owners with trees. 
Also included in the recommendations are steps the City should take to 
better track protected and replacement trees after development is complete . 
Would you strongly support, support, 
oppose, or strongly oppose tree 
removal regulations during property 
development, even when they limit the 
size and extent of potential buildings 
or profits? 
w ,-------------------
so 
40 
30 
20 
10 
Support Oppose 
FIGURE 1 
..... ~------------------------------
City of TiganJ Urban l:orc,tn· Code Rc,-i, iom I \ 'o lumc \ ' I 226 
'' Stakeholder interviews highlighted 
the need for requirements 
addressing the planting of high 
quality trees and ensuring that 
design and maintenance of areas 
such as parking lots and street 
side plantings are sustainable and 
aesthetically pleasing. 
'' 
City of Tigard I Urban Forestry Master Plan 
CHAPTER 2: 
Landscaping Requirements 
Implementation Goal 2: 
Revise Tigard's landscaping code {includes street trees, 
parking lot trees, and other required landscape trees). 
Revising Tigard's landscaping code is the second goal of the UFMP. T he 
intention of the revisions is to improve the quality and protection of the 
City's streetscapes and commercial and industrial landscapes. 
Tigard's exis ting landscaping codes are scattered throughout the 
D evelopment and Municipal Codes. Many of the provisions in 
the landscaping codes lack specificity, are conflicting, and present 
administrative challenges for the City. Also, the City's standards and design 
guidelines do not specify industry accepted installation and maintenance 
requirements for trees. 
Stakeholder interviews highlighted the need for requirements addressing 
the planting of high quality trees and ensuring that design and maintenance 
of areas such as parking lots and street side plantings are sustainable and 
aes thetically pleasing. The Oregon Chapter of the American Society 
of Landscape Architects (OASLA) suggested T igard create a tree and 
landscape design manual with drawings and specifications so that landscape 
architects have a clear idea of the City's overall tree and landscape vision. 
Such a tree and landscape design manual could also address the Tree 
Board's request to translate Code revisions into something the public can 
understand. 
Internally, the lack of a comprehensive tree inventory has led to difficulty 
tracking street trees and required landscape trees. 
Although the UFMP community survey revealed that Tigard citizens are 
highly satisfied with the current overall state of Tigard's urban forest, 74% 
of respondents believe more street trees will be good for the City. Tigard 's 
canopy analysis supports this, as street trees currently provide only 9% 
canopy in City street right-of-ways. T he canopy analysis also found that 
the City's parking lot tree standards are not effective due to the relatively 
low tree canopy in parking lots. (See Figure 2 on next page.) 
Direction for revising Tigard 's landscaping code is included in the 
sub-goals and implementation of section two of the matrix. Specific 
------------------------------~ ..... 
Cit}' of Tigard Urban Forestry Code Revisions I Volume V I 227 
Urban Forestry Master Plan I City of Tigard 
recommendations include developing a landscape design manual with 
drawings and specifications, improving parking lot design, establishing 
a permit system for the planting, replacement, and removal of required 
trees, and improving the tracking and inventorying o f street trees and other 
required landscape trees. 
Based on a 
random sample, 
Tigard parking 
lots (outlined 
in yellow) are 
covered by 
approximately 
6% tree canopy 
(areas highlighted 
in green). 
FIGURE 2 
....-~-----------------------------
City of Tigard Urban l;ot-cs try Code RcYisions I \'olu mc \ ' I 228 
City of Tigard I Urban Forestry Master Plan 
CHAPTER 3: 
Tree Grove Protection 
Implementation Goal 3: 
Develop a tree grove protection program. 
The third goal of the UFMP is to develop a tree grove protection program 
which creates mechanism for protecting T igard's remaining groves of 
native trees while allowing for the full development of property under 
current zoning. 
Many tree groves in Tigard are currently afforded some level of protection 
due to their location in sensitive lands (s tream corridors, steep slopes, 
significant habitat areas, wetlands, and floodplains) as defined by the Tigard 
D evelopment Code. Tigard's D evelopment Code limits the type and 
intensity of development within sensitive lands, and requires permits for 
tree removal in these areas. H owever, the D evelopment Code does not 
explicitly protect tree groves in sensitive lands, and tree removal permits are 
automatically issued if an erosion control plan is provided. Also, currently 
there are no protections for tree groves located outside of sensitive lands. 
Prior to enacting any regulations protecting tree groves, the City must 
comply with Federal, State, and Regional regulations (see Appendix G) . 
Particular attention shall be paid to State laws including the requirements 
for an economic, social, environmental, and energy (ESEE) analysis prior 
to protecting "Goal 5" (natural) resources. 
Some of the stakeholders interviewed for the UFMP such as the Pacific 
Northwest Chapter of the International Society of Arboriculture 
(PNWISA), the OASLA, the Tualatin Riverkeepers and Clean Water 
Services, support the City's efforts to preserve and maintain native trees 
and groves in Tigard. Multiple stakeholders also suggest the City take a 
leadership role in tree grove protection by hiring a greenspace coordinator 
to provide long term maintenance of City-owned natural areas. T he 
HBAMP suggested affected property owners be directly notified about 
regulations and incentives proposed for incorporation into any City code 
calling for the preservation of tree groves. 
T he UFMP community survey shows that Tigard residents support future 
regulations to protect native tree groves. Most residents (~ 5 5%) would 
like to see regulations focused on larger groves of native trees as opposed 
to individual trees of significant size (~28% support). In addition, 37% 
_______________________________ ...._ 
City of T'igard Urban Forestry Code Revisions I Volume V I 229 
Urban Forestry Master Plan I City of Tigard 
o f respondents said they prefer to see new tree regulations focused on 
natural areas as opposed to ornamental trees (~ 3% support). H owever, 
approximately 48% said they would like to see regulations applied to natural 
areas and ornamental trees equally. (See Figure 3 at right.) 73% of respondents 
said the decision of whether to preserve trees should no t be left solely to the 
developer, and a majority (57%) said they support tree regulations even if 
they limit the size and extent of potential buildings or profits. 
While residents prioritize grove pro tection, the canopy analysis revealed 
that T igard's tree groves are disappearing. In 1996, there were 63 canopy 
clusters grea ter than 5 acres in size within the City limits. In 2007, there 
were 48 canopy clusters greater than 5 acres in size. This represents a 24% 
decline in large sized canopy clusters in eleven years. (See Figure 4 on next 
page.) 
As a result o f trends shown in the canopy analysis, community preference, 
and stakeholder input, the UFMP developed a number o f sub-goals and 
action measures to guide the development o f a tree grove protection 
program that is compliant with Federal, State, Regional, and Local 
requirements. Included are recommendations to contact all property 
owners that would be impacted by a tree grove pro tection program and 
providing grove preserva tion incentives. 
If the City were to enact new tree 
protection measures, would you like 
to see them focused on natural areas, 
ornamental landscape trees, both types 
equally, or on something else . 
60 
so 
40 +------
30 
20 
10 
0 
Natural Ornamental Both 
Areas Trees Equally 
FIGURE 3 
- ----------------
Cit)· o fTigan.l Urban l'orestry Code Rc,·isions I \'olumc \ ' I 2.10 
[i996J 
WEIR RD 
-
oCkHAN ST 
... 
BEEF .~t4D RD 
Q 
Canopy Cluster 
Size Class 
Less than .5 acres 
0.5 to .99 acres 
1.0 to 1.99 acres 
2.0 to 4.99 acres 
5.0 or more acres 
Total 
I Total Acres of 
Canopy 
Cover 
366.55 
135.76 
159.25 
190.86 
1100.33 
1952.75 
Acres as a No. 
%of Total of 
Canopy Clusters 
Cover 
18.77% 4356 
6.95% 197 
8.16% 113 
9.77% 61 
56.35% 63 
100% 4790 
City of Tigard I Urban Forestry Master Plan 
No. of Total Acres as a No. No. of 
Clusters Acres of %of Total of Clusters 
as a% Canopy Canopy Clusters as a% 
of Total Cover Cover of Total 
90.94% 584.3 31.54% 7231 93.86% 
4.11% 167.25 9.03% 242 3.14% 
2.36% 177.88 9.60% 131 1.70% 
1.27% 157 8.47% 52 0.67% 
1.32% 766.26 41.36% 48 0.62% 
100% 1852.69 100% 7704 100% 
FIGURE 4 
------------------------------~ ..... 
City o f 'T'igard Urban Forestry Code Re,·isions r Volume v I 231 
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Currently, if there is a dispute between 
neighboring property owners regarding 
a potentially hazardous tree, the City 
does not get involved, and instead 
directs the neighbors to work out a 
solution through civil means. Would 
you strongly support, support, oppose, 
or strongly oppose the creation of a 
program where the City would become 
involved in disputes between neighbors 
regarding hazardous trees? 
70 ~------------------;:~~ 
• Somewhat 
• strongly 
60 
so 
40 
30 
20 
10 
Support Oppose 
FIGURE 5 
City of Tigard I Urban Forestry Master Plan 
CHAPTER 4: 
Hazard Trees 
Implementation Goal 4: 
Develop a hazard tree identification and 
abatement program. 
The fourth goal in the UFMP is to develop a hazard tree identification and 
abatement program that adequately addresses tree hazards on both public 
and private property. 
Currently Tigard's Municipal Code prohibits hazard trees, but there is a 
lack of specificity on what constitutes a hazard and what the mechanism is 
for abating hazards in a timely manner. There is also no formal process for 
identifying and abating tree hazards on City property. 
During the stakeholder interviews the Tree Board suggested that the 
City increase communications between departments. Interdepartmental 
communication is integral to effectively addressing tree hazards in a timely 
manner. Other stakeholders suggested that the City hire a greenspace 
coordinator who could provide proactive management of tree hazards 
in City parks and greenspaces. The HBAMP said the City should allow 
private property owners to manage their land as they see fit, which implies 
the City should have no involvement in private property tree hazard issues. 
As a result of the City's internal coordination meetings, specific methods 
for responding to public tree hazards were developed and are detailed in 
Appendix D. The Parks Division echoed the stakeholders by highlighting 
the need to hire a greenspace coordinator to proactively manage tree 
hazards on City property. 
The community survey results indicate public support for a hazard tree 
identification and abatement program. Approximately 76% of residents 
think more resources should be directed to better maintain and protect 
existing trees. A majority of residents said they would support additional 
funding from increased city fees, charges, or property taxes to fund a more 
comprehensive tree program in Tigard parks and open spaces (~56% 
support, ~39% oppose). A portion of that funding could be used by the 
City for a hazard tree program. Finally, a majority of residents said they 
would support the creation of a program where the City would become 
involved in disputes between neighbors regarding hazardous trees on private 
property (60% support, 38% oppose). (See Figure 5 at left.) 
------------------------------~ ..... 
City of Tigard Urban Forestry Code ReYisions I Volume V I 233 
Urban Forestry Master Plan I City of Tigard 
T he sub-goals and implementation measures recommended in the UFMP 
support the creation of a hazard tree identification and abatement program 
for public and private property. T he recommendations include formalizing 
the City's hazard response protocols, hiring a greenspace coordinator 
to help manage tree hazards on City proper ty, and developing a process 
whereby the City would have authority to become involved in tree hazards 
on private property. In order to provide consistency in tree hazard 
identification and abatement, it is recommended that the City adopt the 
PNWISA Tree Risk Assessment methodology as its standard . 
....-~------------------------------
City of Tigard Urban l'orcstr\' Code Rc,·isions I \'olumc \' I 214 
'' The public showed a preference 
for urban forestry efforts to focus 
on streamside trees and other 
natural forested areas. 
'' 
CityofTigard I Urban Forestry Master Plan 
CHAPTER 5: 
Urban Forestry Program 
Management 
Implementation Goal 5: 
Improve the management of the City's urban 
forestry program. 
Implem entation Goal S was developed to improve the coordination and 
management of the City's urban forestry program . 
T igard's urban fores try program is currently implemented by multiple City 
departments and divisions. In addition, code provisions rela ting to urban 
fores try are scattered throughout the Municipal and D evelopment Codes. 
Management o f City-owned tree and fores t resources has been declining 
as more land is acquired without additional funding for maintenance 
and proactive management. Improved communication between City 
departments and divisions, unifying urban fores try related Code provisions, 
and providing adequate staffing is needed for more effective management 
o f the City's urban forestry program . Also, securing a sustainable funding 
source will be necessary to provide long term support of the urban forestry 
program as the Tree Fund declines due to less future development. 
Stakeholders such as tl1e PNWISA and Clean Water Services suggested iliat 
ilie City hire a greenspace coordinator to proactively manage City tree and 
fores t resources. T he Tualatin Riverkeepers said ilie City needs to establish a 
sustainable source of funding for its urban fores try program to assist in the 
long term management of invasive species. T he Tree Board suggested iliat 
iliere needs to be more coordination between City departments and divisions 
when administering ilie urban fores try program. Aliliough a minority view, 
tl1e HBAMP's position is iliat iliere should be no urban forestry program 
because ilie costs outweigh ilie benefits of such a program. 
T he City's internal coordination meetings highlighted the need for more 
communication between departments and divisions. More communication 
would improve the management of tree hazards, ensure City development 
projects are adhering to applicable Code requirements, improve the 
tracking of trees after development, and provide more transparency as to 
how and where the Tree Fund is being utilized. T he internal coordination 
meetings also highlighted the need for a written set of tree pro tec tion 
--------------------------------------~ ...... 
City of Tigard Urban Fores try Code ReYisiom I Volume V I 235 
Urban Forestry Master Plan I City of Tigard 
and replacement standards for City projects so that the City can take a 
leadership role in urban fores try. 
T he community survey results demonstrate public support for increased 
funding through fees and taxes for the City's urban fores try program 
(~ 56% support, ~39% oppose) . (See Figure 6 at right.) T he public showed 
a preference for urban fores try efforts to focus on streamside trees and 
o ther natural fores ted areas. T hese results indicate that residents would 
support the hiring o f a greenspace coordinator to directly manage the 
nearly 180 acres of City-owned tree canopy in Tigard . 
T he sub-goals and implementation measures recommended in the UFMP 
Would you strongly support, support, 
oppose, or strongly oppose additional 
funding from increased City fees, 
charges or property taxes to fund a 
more comprehensive tree planting and 
maintenance program in Tigard parks 
and open spaces? 
60 .-----------------------------------
• Somewhat 
so 
to support the goal o f improved City managem ent include developing 40 
methods for inventorying and tracking trees and urban fores try related 
expenditures, developing a written set o f urban fores try standards for 3o 
City projects, securing a sustainable funding source for urban fores try, and 
hiring a greenspace coordinator to manage the City's natural areas. zo 
10 
Suppo rt Oppose 
FIGURE 6 
....-~-------------------------------
Ci ty of Ti~-,>anl Urban r:ore> try Code RcYi>iom I \ 'olume \ ' I 2_)(, 
'' In 2007, Tigard had 24% citywide 
tree canopy which is well below 
American Forests' target 
recommendation of 40% for 
Pacific Northwest cities. 
'' 
City of Tigard I Urban Forestry Master Plan 
CHAPTER 6: 
Stewardship 
Implementation Goal 6: 
Develop an urban forestry stewardship program. 
Urban Forest stewardship has been a vital component of life in the area 
now known as Tigard for thousands of years. 3,500 years before present, 
Kalapuya (Native Americans) began managing the forests of the Willamette 
Valley using fire (pyroculture). At about the time of European settlement 
in 1851, canopy coverage within the current City limits of Tigard was 
estimated to be 52.4% (3,966.9 acres). The predominant tree species were 
Oregon ash, red alder, bigleaf maple, willow, black cottonwood, Oregon 
white oak, western red cedar, and Pacific dogwood in the riparian and 
wedand areas. The upland areas were dominated by Douglas-fir, bigleaf 
maple, grand fir, Pacific dogwood, western hemlock, Oregon white oak, red 
alder, western red cedar, and ponderosa pine. (See Figure 7 below.) 
Forest types/ 
vegetation 
present circa 
1851 .1 
Estimated 1851 
canopy cover 
within 2008 
Tigard city limits 
(outlined in red) 
based on forest 
types is 52.4%.2 
FIGURE 7 
111ulse, D., S. Gregory, and J. Baker, eds. 2002. Willamette River Basin Planning Atlas: Trajectories of 
Environmental and Ecological Change. The Pacific Northwest Ecosystem Research Consortium. Corvallis, 
O R: Oregon State UniYersity Press. 
'Johnson, B.R., 2008. Personal communication on November 12. Associate Pro fessor of Landscape 
.\ rchitccturc, UniYersity of Oregon. Eugene, O R. 
_______________________________ ..._. 
City of Tigard Urban Forestry Code RcYisions I Volume V I 237 
Urban Forestry Master Plan I City of Tigard 
Abbreviation Forest Type Vegetation l}'Pe 
FF 
OFZ 
OFOPZ 
FFP 
FALW 
OFOZ 
FFHPP 
OFHC 
FFHCBu 
FFHC 
FFO 
FFA 
Closed forest; Upland 
Woodland 
Woodland 
Closed forest; Upland 
Closed forest; Riparian 
& Wetland 
Woodland 
Closed forest; Upland 
Woodland 
Closed forest; Upland 
Closed forest; Upland 
Closed forest; Upland 
Closed forest; Riparian 
& Wetland 
Douglas fir forest, often with big leaf maple, grand fir, 
dogwood, hazel , yew. No other conifers present. No Oak. 
Douglas fir woodland or "timber" often with bigleaf maple, 
alder or dogwood. No oak, hemlock or cedar. Brushy 
undergrowth of hazel, vine maple, young Douglas fir, 
bracken etc. 
"Scattering" or "thinly timbered" Douglas fir-white oak-
ponderosa pine woodland, with brushy undergrowth of 
hazel , bracken, etc. May include small openings. 
Douglas fir-ponderosa pine forest; no oak, includes ash, 
red alder, hazel , Oregon grape, vine maple. 
Ash-alder-wi llow swamp, sometimes with bigleaf maple. 
Often with vine maple, ninebark, hardhack, cattails. Ground 
very soft, mirey or muddy, usually with extensive beaver dams. 
Scattering or thinly timbered Douglas fir-white oak 
woodland. May contain bigleaf maple; brushy understory of 
hazel, young oaks, oak brush, young fir, bracken. No pine. 
Mixed conifer forest, with ponderosa pine. May include 
Douglas fir, red cedar, western hemlock, bigleaf maple, 
white oak, red alder, dogwood, vine maple. 
Conifer-dominated woodland; various combinations of 
Douglas fir, red cedar, hemlock, bigleaf maple, white oak, 
red alder, dogwood. No ash present. 
FFHC, but burned, often with scattered trees surviving fire. 
Mesic mixed conifer forest with mostly deciduous under-
story. May include Douglas fir, western hemlock, red cedar, 
grand fir, bigleaf maple, yew, dogwood, white oak, red alder. 
Douglas fir-white oak (big leaf maple) forest, with brushy 
understory of hazel , young oak, oak brush, oak sprout, 
bracken, briars, sometimes willow. 
Ash-mixed deciduous riparian forest with combinations 
of red alder, bigleaf maple, black cottonwood, white oak, 
dogwood. Conifers may be present in small quantities. 
r\s Tigard became settled, native fores ts were cleared for agricultural uses 
and timber to help support development. After Tigard was incorporated in 
1961, the City began passing codes to manage the urban fores t beginning 
in 1967 with street tree planting requirements, and continuing in 1983 and 
1997 with the passage o f codes that regulated tree removal. The City hired 
its first urban forester in 1998 and created the Tree Board in 2001 . The City 
of Tigard has been named a Tree City USA every year since 2001 and was 
awarded the Tree City US.A Growth Award in 2009 for its expanded urban 
fores try efforts. 
In 2007, Tigard had 24% citywide tree canopy which is well below 
American Forests' target recommendation of 40% for Pacific Northwest 
Logging in Tigard area- 1904 
The Hunziker Dairy Farm near Garden 
Home. Mr. Hunziker is in center of 
picture wearing hat and coat. 
....-~------------------------------
City of Tigard Urban l:orc,lry Code Rc,·i,ion' I \ 'olumc \ ' I 218 
'' The City of Tigard has been 
named a Tree City USA every 
year since 2001 and was awarded 
the Tree City USA Growth Award 
in 2009 for its expanded urban 
forestry efforts. 
'' 
TREE CITY US.K 
CityofTigard I Urban Forestry Master Plan 
cities. An analysis of existing tree canopy combined with plantable 
locations confirmed that 40% citywide tree canopy cover is achievable in 
Tigard. While citywide tree canopy is currently stabilized (1% decrease 
from 1996-2007), it is becoming increasingly fragmented Oarger groves 
are being replaced by individual trees). (See Figure 8, next page.) Because 
78% o f Tigard's tree canopy is on priva te proper ty and only 7% of 
Tigard's land area is on buildable lands, it is critical to develop an urban 
fores t stewardship program that includes all residents and property 
owners in the City. 
------------------------------~ ..... 
Ci ty o f Tigard Urban Forestry Code Rc,·isions I Volume V I 239 
Urban Forestry Master Plan I City ofTigard 
Canopy By 
Property Ownership 
-
9 r~'"R~p.s 
13125 SW H oi/ 8/yd 
Tirord, Orf'ron 91121 
50 3 . 639 . 4171 
www.llrord-or.rov 
P\.1•1 
Legend 
c=J City of Tigard 
I Public Right-of-Way 
c=J Other Public Entities 
Private Land 
- Canopy Cover 
c=J Tigard Ci ty Limits 
Taxlot Ownership I Number of Taxlots 
City of Tigard 235 
Public Right-of-Way n/a 
Other Public Entity 79 
Private 15,880 
Total 16,194 
I Total Acres I Acres of Canopy Percent Canopy 
Cover in 2007 Cover in 2007 
388.41 179.18 46.13% 
1,288.30 117.45 9.12% 
431.65 105.1 24.35% 
5,447.64 1,450.96 26.63% 
7,556.00 1,852.69 24.52% 
FIGURE 8 
....-~------------------------------
Citr of Tigard Urban l'orcstry Code Rc,·isions I \'olumc \ ' I 240 
City of Tigard I Urban Forestry Master Plan 
Most stakeholder groups support the goal of developing and participating 
in an urban forest stewardship program. The Tree Board wants future 
urban forestry codes to address areas outside development and provisions 
translated into something the public can understand. They also want 
more community education on urban fores try issues, and for the City to 
continually measure progress on canopy changes and community attitudes 
so that policy effectiveness can be easily evaluated in the future. 
Portland General E lectric and the Tigard-Tualatin School District have 
offered to partner with the City on tree planting and maintenance projects. 
The Tualatin Riverkeepers and Clean Water Services would like more focus 
on managing invasives in natural areas and have offered to assist the public 
on long term resource management. 
Although there is a high level of satisfaction with the current state of 
Tigard's urban forest, survey results show the public would support an 
urban forest stewardship program with 76% of residents wanting more 
resources directed towards maintaining and protecting existing trees. (See 
Figure 9 .) Many would be willing to become directly involved with 52% of 
residents saying they would prefer volunteering to plant and maintain trees 
rather paying a fee to the City to do it. Residents also want to protect the 
trees in their existing neighborhoods with 75% saying they would support 
regulations for developed private property that would protect large, healthy 
trees. (See Figure 1 0.) 
The sub-goals and implementation measures in the UFMP that support the 
goal of developing an urban forest stewardship program include increasing 
urban forestry outreach materials, utilizing funding for tree planting and 
maintenance on public and private property, and developing regulations 
to prevent clear cutting. Also, long term objectives include periodically 
updating the Urban Forestry Master Plan in order to track progress and 
set new goals, achieving not net loss of tree canopy between 2007 and 
2015, and achieving 32% and 40% citywide tree canopy by 2027 and 2047 
respectively. 
It would benefit the City if more 
resources could be directed to better 
maintain and protect existing trees. 
FIGURE 9 
Would you strongly support, support, 
oppose, or strongly oppose city 
regulations that would provide some 
level of protection for large, healthy 
trees on developed private property? 
This would apply to all current private 
property. 
Support Oppose 
FIGURE 10 
_______________________________ ..._. 
City of Tigard Urban Forestry Code ReYisions I Volume V I 241 
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Glossary 
Buildable Lands Inventory (BLI) -The Tigard BLI defines buildable 
land as: 1) privately owned taxlots that are vacant; or 2) larger priva tely 
owned taxlots that are developed but with % acre or greater of the taxlot 
vacant. Additionally, publicly owned land, sensitive lands, water quality 
tracts, and homeowner association owned lots within subdivisions are not 
included. Platted, vacant lots within subdivisions are considered buildable 
until development has occurred. 
Canopy Cluster - A contiguous area of canopy cover created by a 
group of trees. Using Feature Analys t software on aerial photos of Tigard, 
a canopy layer was created in Tigard's GIS database. T his layer was used to 
analyze the size and location of canopy clusters in Tigard. 
Canopy Cover - The area above ground which is covered by the trunk, 
branches, and foliage of a tree or group of trees' crowns. 
GIS (Geographic Information System) - An integrated collection 
of computer software, and data used to view and manage information 
about geographic places, analyze spatial relationships, and model spatial 
processes. A GIS provides a framework for gathering and organizing spatial 
data and related information so that it can be displayed and analyzed. 
Invasive - Species that spread at such a rate that they cause harm to 
human health, the environment, and / or the economy. 
Ornamental Trees - Trees cultivated primarily for aesthetics and other 
direct human benefits. 
Sensitive Lands - As defined by the Tigard Development Code, lands 
potentially unsuitable for development because of their location within: 
1. The 1 00-year floodplain or 1996 flood inundation line, whichever is 
greater; 
2. Natural drainageways; 
3. Wetland areas which are regulated by the other agencies including the 
U.S. Army Corps of E ngineers and the Division of State Lands, or 
are designated as significant wetland on the City of Tigard "Wetland 
and Stream Corridors Map"; 
4. Steep slopes of 25% or greater and unstable ground; and 
5. Significant fish and wildlife habitat areas designated on the City of 
Tigard "Significant Habitat Areas Map." 
--------------------------------....-
City of Tigard Urban Forestry Code Re"isions I Volume V I 243 
Urban Forestry Master Plan I City of Tigard 
Tree Density - The number of trees per unit area . 
Tree Fund - A fund created by the City of Tigard for the purpose of 
replacing trees that are removed during development activities. It is funded 
by development pro jects that do not plant replacement trees, and is used 
by the City to cover its costs of planting an equivalent amount o f trees 
elsewhere. 
Tree Grove - A group of trees, o ften with contiguous crowns, which 
form a visual and / or biological unit. 
Tree Hazard Assessment - A systematic process of identifying tree 
hazards. 
Tree Risk Assessment - A systematic process to determine the level 
of risk posed by a tree, tree part, or group of trees . 
....---------------------------------
City of Tigard Urban l ;or~stry Code Rc,·isions I \ "olumc \ ' I 24~ 
City of Tigard I Urban Forestry Master Plan Appendix 
Appendix 
APPENDICES 
Appendix A: Urban Fores try Survey Results al 
Appendix B: Canopy Analysis a16 
Appendix C: Stakeholder Interview Notes a24 
Appendix D : City of Tigard, Internal Coordination Meeting N otes a39 
Appendix E: Urban Fores t Section of the Comprehensive Plan a46 
Appendix F: Tigard Urban Forestry Historical Timeline a55 
Appendix G: Review of Current Federal/State/ Regional 
Urban Fores try Policy Framework a56 
Appendix H: Review of Current City of Tigard 
Urban Forestry Policy Framework a63 
Appendix 1: Resolution N o. 09-69- A Resolution Accepting 
the City of Tigard's Urban Forestry Master Plan a71 
-------------------------------..... 
City of Tigard Urban Forestry Code Re,·isions I Volume V I 245 
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City of Tigard I Urban Forestry Master Plan Appendix 
APPENDIX A 
CITY OF TIGARD 
2008 URBAN FORESTRY SURVEY 
STEVE JOHNSON & ASSOCIATES * P. 0. BOX 3708 * EUGENE, OREGON 97403 
TOPLINE FREQUENCIES 
**Topline results include the text of each question, the response categories, and the number and percent of 
responses in each categmy. All questions include categories for Refused (7 or 97), Don't Know (8 or 98) and No 
Answer (9 or 99). In the interest of space, responses such as "I don 'I know, " "I can 'I think of anything, "and 
"no comment" have been removed f rom the document. The "open answers" are recorded verbatim. They have 
been corrected for spelling but not grammar. 
HELLO I Hello, I'm calling on behalf of the City of Tigard. They have asked us to conduct a 
survey of residents 18 and older about trees in the city and urban forestry. The survey takes 
about ten minutes and is vo luntary and anonymous. I'd like to start now. 
[INTERVIEWER NOTE: IF RESPONDENT SELF IDENTIFIES AS UNDER 18 ASK FOR 
SOMEONE OVER 18. IF NO ONE IS A VAJLABLE TRY AND SCHEDULE CALL 
BACK. IF THIS IS THE LAST DIAL ATTEMPT GO TONOQUAL] 
PRESS START TO BEGIN - OR - PRESS DISPO TO SCHEDULE CALLBACK 
*INTRO FOR PARTIALS: Hi, I'm calling back to finish an interview for the City ofTigard 
that we began earlier. Is that (you/person available)? 
SATISl I'd like to begin by asking if you are very satisfied, satisfied, dissatisfied or very 
dissatisfied with the quantity and quality of trees in the fo llowing locations. First, what about 
the trees on your street? 
PROBE: Are you very satisfied, satisfied, dissatisfied, or very dissatisfied with the quantity 
and quality of trees on your street? 
I VERY SATISFIED 103 25 .75% 
2 SATISFIED 246 61.5% 
3 DISSATISFIED 32 8% 
4 VERY DISSATISFIED 10 2.5% 
7 REF/ 8 DK/9 NA 9 2.25% 
400 100% 
SATIS2 What about the trees in your neighborhood? 
PROBE: Are yo u very satisfied, satisfied, dissatisfied, or very dissatisfied with the quantity 
and quality of trees in your neighborhood? 
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City of Tigard Urban Forestry Code Re,·isions I Volume V I 247 
Urban Forestry Master Plan Appendix I City of Tigard 
APPENDIX A 
I VERY SATISFIED 
2 SATISFIED 
3 DISSATISFIED 
4 VERY DISSATISFIED 
7 REF/ 8 DK/9 NA 
104 26% 
242 60.5% 
43 10.75% 
5 1.25% 
6 1.5% 
400 100% 
SATIS3 What about trees in the city as a whole? 
PROBE: Are you very satisfied, satisfied, dissatisfied, or very dissatisfied with the quantity 
and quality oftrees in the city as a whole? 
1 VERY SATISFIED 61 15.25% 
2 SATISFIED 251 62.75% 
3 DISSATISFIED 59 14.75% 
4 VERY DISSATISFIED 10 2.5% 
7 REF/ 8 DK/9 NA 19 4.75% 
400 100% 
HOOD Does your neighborhood need more trees and landscaping to improve 
its appearance and environmental quality? 
I YES 
2NO 
7 REF/ 8 DK/9 NA 
101 25.25% 
294 73.5% 
5 1.25% 
400 100% 
IMPORTl Now I would like to read you some statements people have made about trees. 
For each one, would you tell me if you strongly agree, agree, disagree, or strongly disagree. 
First, trees are important to a community' s character and desirability as a place to live. 
PROBE: Do you strongly agree, agree, disagree, or strongly disagree? 
I STRONGLY AGREE 249 62.25% 
2AGREE 138 34.5% 
3 DISAGREE 10 2.5% 
4 STRONGLY DISAGREE I 0.25% 
7REF/ 8DK/9NA 2 0.5% 
400 100% 
IMPORT2 It is important to me to have a view of trees from my home. 
PROBE: Do you strongly agree, agree, disagree, or strongly disagree? 
I STRONGLY AGREE 218 54.5% 
City of Tigard Urban Forestry Survey- 2008 
Top I ine Frequencies Page 2 
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City or Tigard Urban l'orc>try Code Rc,-i,iom I \ 'olumc \ ' I 248 
City of Tigard I Urban Forestry Master Plan Appendix 
2AGREE 
3 DISAGREE 
4 STRONGLY DISAGREE 
7 REF/ 8 DK/9 NA 
148 
28 
4 
2 
400 
37% 
7% 
I% 
0.5% 
100% 
IMPORT3 Trees contribute to the value of residential property. 
PROBE: Do you strongly agree, agree, disagree, or strongly disagree? 
I STRONGLY AGREE 200 50% 
2AGREE I70 42.5% 
3 DISAGREE 19 4.75% 
4 STRONGLY DISAGREE 3 0.75% 
7 REF/ 8 DK/9 NA 8 2% 
400 IOO% 
IMPORT4 Trees contribute to the value of commercial property. 
PROBE: Do you strongly agree, agree, disagree, or strongly disagree? 
I STRONGLY AGREE I25 3I.25% 
2AGREE 205 51.25% 
3 DISAGREE 45 I1.25% 
4 STRONGLY DISAGREE 3 0.75% 
7 REF/ 8 DK/9 NA 22 5.5% 
400 100% 
IMPORTS More street trees would be good for the City. 
PROBE: Do you strongly agree, agree, disagree, or strongly disagree? 
I STRONGLY AGREE 97 24.25% 
2AGREE 202 50.5% 
3 DISAGREE 62 I5.5% 
4 STRONGLY DISAGREE 9 2.25% 
7 REF/ 8 DK/9 NA 30 7.5% 
400 100% 
APPENDIX A 
IMPORT6 It would benefit the City if more resources could be directed to better maintain 
and protect existing trees. 
PROBE: Do you strongly agree, agree, disagree, or strongly disagree? 
I STRONGLY AGREE 102 25.5% 
City of Tigard Urban Forestry Survey- 2008 
Topline Frequencies Page 3 
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City of Tigard Urban Forestry Code Re,·isions I Volume V I 249 
Urban Forestry Master Plan Appendix I City of Tigard 
APPENDIX A 
2 AGREE 
3 DISAGREE 
4 STRONGLY DISAGREE 
7 REF/ 8 DK/9 NA 
203 50.75% 
50 12.5% 
10 2.5% 
35 8.75% 
400 100% 
IMPORT7 The City should require that some trees be preserved and new ones planted on 
sites that are being developed. 
PROBE: Do you strongly agree, agree, disagree, or strongly disagree? 
I STRONGLY AGREE 160 40% 
2AGREE 193 48.25% 
3 DISAGREE 30 7.5% 
4 STRONGLY DISAGREE 9 2.25% 
7 REF/ 8 DK/9 NA 8 2% 
400 100% 
FORESTl All cities have an urban forest. The urban forest in Tigard consists ofthe trees in 
parks, along streets, in yards, on empty lots and in forested areas. Do you think the overall 
quality of Tigard's urban forest has increased, decreased or stayed the same in the last 10 
years? 
I INCREASED 
2 DECREASED 
3 ST A YEO THE SAME 
7 REF/ 8 DK/9 NA 
73 
166 
117 
44 
400 
18.25% 
41.5% 
29.25% 
II% 
100% 
FOREST2 In the future , do you expect the overall quality of Tigard's urban forest to 
increase, decrease, or stay the same? 
I INCREASED 
2 DECREASED 
3 ST A YEO THE SAME 
7 REF/ 8 DK/9 NA 
113 
126 
138 
23 
400 
28.25% 
31.5% 
34.5% 
5.75% 
100% 
FOREST3 On a scale of 1-10, where one is poor and I 0 is excellent , how would you rate 
the extent and appearance oftrees in Tigard? 
I ONE 
2TWO 
3 THREE 
4FOUR 
3 
0 
14 
II 
0.75% 
0% 
3.5% 
2.75% 
City of Tigard l 'rban Forestry Survey - 2008 
Topline Frequencies Page 4 
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City ofTigarJ Urban l'orc, try CoJe Rc,-i,ion' I \ 'olume \ ' I 250 
City of Tigard I Urban Forestry Master Plan Appendix 
APPENDIX A 
5 FIVE 61 15.25% 
6 SIX 48 12% 
7SEVEN 96 24% 
8 EIGHT (GO TO TAXI ) 119 29.75% 
9 NINE (GO TO TAXI) 19 4.75% 
10 TEN (GO TO TAXI ) 24 6% 
7 REF/ 8 DK/9 NA 5 1.25% 
400 100% 
FOREST4 What could be done to improve the appearance and quality of trees in Tigard? 
OPEN ENDED- RECORD EXACT RESPONSE 
Not cut them all. They are cutting out more than they are putting in. They should require 
developers to keep some of the existing trees. 
Better maintenance. 
More variety. 
They need to plant more trees when they remove them. Do not just plant commercialized 
trees. 
Maintain the trees. Trimming them and things like that. 
Ask the people to clean up more. During the fall , clean up sidewalk areas like they should. 
More maintenance, 
I say plant more, just preserve the ones that are there. 
Certain areas. Save certain trees. 
Taken care ofthe trees. 
I don't have any good ideas. Don't cut down more big trees. 
Trimmed when it comes to wires, and in areas with no trees new ones could be planted. When 
they are doing commercial development they should plant trees when they are done 
building. 
In the vast expanses of parking lots there should be shade trees for the cars. It would help with 
gas so people don't have to use the AC. Shade trees help a lot. 
Public awareness. 
Developers not remove existing trees as much. 
One thing I don't like is the power company coming along and trimming them to look stupid. 
Better trees that don't tear up streets and utilities. 
Don't do anything. They'll grow by themselves. No sense in paying tax payers' money on 
trees that can take care of themselves. 
High quality maintenance. 
Let the trees get older. 
You know you do a good job. Keep up the good work. 
Add trees along Durham Road and downtown Main Street. 
More frr trees or pine green trees. 
Plant more, I guess. 
I think more of them. And better maintenance of the area around the trees. 
Plant more trees; take care ofthem. 
They don't have a nice setup in Tigard, lack of parks. 
City of Tigard Urban Forestry Survey- 2008 
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City of Tigard Urban Forestry Code Rc,·isions I Volume V I 251 
Urban Forestry Master Plan Appendix I City of Tigard i 
APPENDIX A 
Maintenance 
More maintenance from landowners and the city. 
Better protection of the exciting trees in areas. 
Keeping them clean, away from street signs and pruning them. 
Quit cutting them down I think. 
They could be taken care of. 
Trimming. 
Quit cutting them down. 
They can be trimmed up so they can plant more trees. 
Plant more trees. 
Prevent cut down of existing ones, plant more trees. 
They could put the areas back that used to be there, that are gone. 
Plant more. 
I think if they planted the proper trees so that the roots would not appear and break up the 
sidewalks. I think people either put them down and don't pull out the roots. 
Ones left are well maintained, pick up leaves off sidewalks and streets for bikers. 
To trim them. 
Plant more street trees on Greenburg Road. 
Not letting people cut them down. 
Grow more. 
There are places where there are a lot of trees and places where there are none, trees should be 
everywhere, especially where there are none. It would also be good to discus the 
things people don't want to see, especially industrial areas. Trees should be used to 
shield them from their neighbors. 
Streets be lined with trees. 
Leave them alone. 
Basic maintenance. 
I think if there is some sort of a plan. When you build new housing areas and existing areas 
you should have a comprehensive plan about the comprehensive trees. Whether the 
city is going plant the trees or it is going to be left to individuals. 
In some areas I think you need to have management people that know what is going on. 
Placement of trees and people with knowledge of what is going on. It would be more 
beneficial to have more parks. Percentage of parks in a residential area. 
Protection of some of the areas, like stream land from development. 
Maintenance around power lines. 
More trees. Nothing else. 
Trees aren't taken care of well, trees in vacant lots should become less neglected . 
Fertilize. 
Find a way to keep away all the leaves. 
Pruning and maintained health, be maintained better. 
More volunteers to maintain them. 
Plant more trees! Plant more quality trees. 
I think that we need to keep the landscaping up. We need to maintain our trees. If we have 
more trees we will have a better community. 
City of Tigard Urban Forestry Survey- 2008 
Topline Frequencies Page 6 
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City of 'l'igan.l Urban Forestry Code Rc,·isions I \'olumc \ ' I 252 
CityofTigard I Urban Forestry Master Plan Appendix 
APPENDIX A 
Put them in strategic locations like downtown. They should put a ton of trees downtown. 
They want to improve downtown they should put in good trees. Don't put them there 
for no reason. 
Just so much building going on more regulations about what trees need to remain. 
Probably the amount. 
There could be more ofthem on major highways. Highway 99 has none on that road. 
Plant more trees. 
More placed in better locations, not be so messy. 
Add more trees, keep the exciting trees. 
Better pruning with trees along the streets a lot that have grown big and unruly. 
Better maintenance. I think that some ofthe street trees get in the way. 
Probably just more attention to them. The property owners need to pay more attention to their 
trees probably. If we are going to have trees, they need to be maintained. 
Not be willing to cut so many when they are developing. 
Don't know, maintain them. 
Get the city counsel in the city forest , they should be running the city not the trees. 
Maintain damage is done. 
Leave them standing, pruning assisting their health. 
Maintain what they have and not let the new buildings do away with the trees. Plant new ones 
after they have built homes or buildings. 
Plant more and not chop down forest to put up condos. 
I wish people would take care of trees better. 
They could have more trees where there are no trees. 
More street trees. 
Don't think anything should be done. 
Trim them. 
Highway 99 at the bridge. Just be conscientious. 
Plant more trees, when you remove trees, plant trees where the space is available. It should be 
a law to plant trees. 
Provide good maintenance. 
Downtown area needs more trees. 
Old trees be cut down, plant new ones. 
Preserve during development. 
Better overall maintenance. 
Better maintained. 
Pick up more leaves. 
I don't have a problem with it, so nothing. 
Need more trees in old town. 
Cut them all down, too many large trees, they are blocking the view of everything. They need 
to at least be trimmed. 
Developer should put trees of appropriate size for the lot. 
A little bit better maintained by people that take care ofthe trees. 
More of them along the main streets. 
They could be preserved. Planting the right trees. And more of them. 
Trimming and landscaping around trees. 
Like the downtown, they made it look all cutesie. 
City of Tigard Urban Forestry Survey- 2008 
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City of Tigard Urban Forestry Code Re,·isions I Volume V I 253 
Urban Forestry Master Plan Appendix I City of Tigard 
APPENDIX A 
Plant more, let more streets be planted next to trees. Less shopping malls, have an area of 
trees planted, 99 west. They put ugly storage unit, they cut down beautiful trees for 
that. 
Improve the city council decisions. 
Pruning. 
A little bit of pruning. 
There could be improvements on highway 99 and on commercial properties. I see a lot of 
death that needs to be maintained a little bit better. More trees on busier streets. 
Plant more of them, take care of them, and cut their branches and everything. 
First of all plant more trees ifthere is the space. 
Largely, plant new ones and stop cutting down the old ones. 
Probably more aggressive street tree planting program. Out reach to property owners that 
have trees and preserve them. 
Most of the trees are on private property. As to the ones that are on public domain, they 
should be maintained professionally with an eye towards long term growth. 
I like where homes don't go right to the creek and there is green spaces along creeks. 
Maybe more trimming on trees. 
Plant more. 
Expert looking at the issue. 
Old ones let go. Cleaned up. 
By preserving existing trees. 
Better maintenance. 
Leave them alone. 
Remove many ofthem. Public works departments are not funded to protect neighborhoods as 
a result of leaf fall. There is not enough street sweeping services. 
Downtown could plant trees. 
Lining the streets and putting them in parks, but I think they're doing that right now. Where I 
live there are many trees in the community. 
More trees, as far as the existing trees, I'm not sure what to say about their quality and 
appearance. 
Proper maintenance of the trees and removal of the dead or improper growth. 
Plant more, rip up cement and plant trees. 
In certain neighborhoods there could just be more of them. And more yard debris pick-up, so 
that people are not afraid to have trees. Anything that would make having a tree easier 
would be good. 
I would like to see their messes cleaned up quicker. 
If they had left the old trees to live, it would have been better. They put up some new dinky 
trees. And they just don't look as good. It's too late. 
Maybe better maintained and kept trees. 
Maintain existing trees. 
Plant more. City to replace trees that are deceased or need to be replaced. 
Cut down dying trees, take care of trees next to main roads. 
Stop cutting them down. When a large tree is cut down, requires two of three tree in their 
place. 
Adding variety. 
More of them in public areas. In downtown Tigard. 
Cit) of Tigard Urban Forestr) Survey- 2008 
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City of'J'igaru Urban For~stry Cou~ Rc,·isions I \ 'olumc \ ' I 254 
City of Tigard I Urban Forestry Master Plan Appendix 
I think they need to plant more trees along streets and in newly developed areas. 
Add some along 99. 
Better trimming and maintenance. 
APPENDIX A 
Maybe more appropriate trees in the area they're going to be planted. I guess I'm thinking 
about some trees are planted too close to the street, and that causes problems with 
leaves in the sewer and sidewalks heaving from the roots. 
Maintenance 
Maintenance and replanting with trees that die. 
Just encourage more people to plant proper trees and take care of the ones they have. And not 
cut them down unnecessarily. 
Pruning. 
In the greenway, we have lots of English ivy that is destroying our trees. Dead trees. 
Not cutting down massive amounts when they build new areas. Plants more trees along the 
parks. 
I don't know what could be done to make them better. I noticed when new development is 
going in were their is a forestry areas and they take out the tress and I don't like that. I 
don't like the ripping up of the stuff along Vano Creek. 
Stop chopping down trees. 
More maintenance and planting more trees. 
Plant more decorative trees. Some of the ones that flower in the spring. More evergreens. The 
big scrub maples, big yellow leaves. Replace stuff with more colors for spring and fall. 
More red maples. 
Planting more tress in the downtown Tigard area and taking care of trees that are at the end of 
their life. Taking down and replacing trees that are dying. 
They're in pretty good shape. 
Maintain the one we have, and plant more. 
Keep them trimmed away from the important stuff. 
Replace trees as they are taken out. 
Medians planted with trees. Uniform tree type on various streets so that it isn't so raged 
looking. 
Better up keep. 
Get rid of the old ones that are dying. Just clean up. 
Plant more. Help maintain the huge fir trees. 
I think that the city needs to be a little more proactive in trimming them so things can be seen. 
So that people who are unfamiliar with the area can see the street signs. It's a huge 
sign. If people are elderly then they can't trim them themselves. Need to be more 
proactive. 
I really don't know if I like a tree in front of my house, I wouldn't plant it but I think trees are 
important. 
Stop cutting down all the trees on all developments. 
Keep them trimmed up a little bit nicer and leaves in the fall are a big problem, they make a 
mess. 
Nothing I think they are fine. 
Take down the trees that drop leaves. 
I'm not sure we need more trees. 
City of Tigard Urban Forestry Survey- 2008 
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City of Tigard Urban Forestry Code Re,-isions I Volume V I 255 
Urban Forestry Master Plan Appendix I City of Tigard 
APPENDIX A 
I don't really know, stop cutting down all the trees, build where they do not have to remove 
trees. 
Just prune and thin out the trees. Increase the health of trees. 
More open green spaces and more trees in commercial areas. 
Plant more trees. 
Better maintaining by replanting. More planting. 
Plant more. 
I'm thinking ofthe one on the corner of my lot, it has pruning problems due to the power 
lines. Jt really distorts the shape of the tree. 
Stop building houses. 
Cutting them back and some pruning them. 
More planting. 
Do not cut down anymore than they absolutely have to. 
I think maybe stronger education on how to take care of trees. 
More development of downtown, Tigard with lots of trees and landscaping. 
Better management by the city and government. 
When developing, keep more trees that are already existing. Or replanting trees that have been 
taken down to build a new house. 
Regular maintenance. 
I think there should be more, plant more. 
I feel that every time they cut one down they put new ones in. They've stopped doing that. 
They don't replace anything, it looks like a concrete forest . 
I think more of the visual stuff and getting the community more involved, too many 
businesses. 
I think they are okay. 
I don't have an opinion on it . 
Planting to include green space and park settings, Bull Mountain is an example ofhow not to 
do it. 
More trees. Better upkeep. 
Not cut them down. 
I would think that they could be better shaped, and trimmed when needed. I fit the location 
where they fit size wise. 
Leave the consumer alone. They have their own trees, so let them do what they want. 
Some of them need to be shaped better. The ones on the road. 
I don't know, just make sure they're maintained and plant new trees as ones die or become 
available. 
They are properly cared for and planted more of them. 
Better maintenance. 
Better care and clean up. 
Variety and maintenance. 
I would presume plant more . 
We're going to suggest the city does a better job of maintaining them. To improve our park, 
we're on Woodard park, it would improve the park if they would thin the trees that are 
diseased and prune them, or remove them. 
Quit cutting them down for new developments. 
Planting more trees. 
C'it) of Tigard l frban Forestr) Survey - 2008 
Top I ine Frequencies Page I 0 
lmlllll~--------------------------------------------
City of Tigard Urban l'orcstry Code RcYisions I \'olumc \' I 25o 
CityofTigard I Urban Forestry Master Plan Appendix 
Just constant vigilance. 
More and just more. 
Plant trees where there are no trees. Where I live there are lots of trees. 
Leave them alone. 
Better maintenance. 
Plant more. 
APPENDIX A 
TAXI Currently, property owners are responsible for maintaining street trees in front of their 
property. Would you strongly support, support, oppose, or strongly oppose a program that 
transfers the responsibility for maintaining street trees to the City? 
1 STRONGLY SUPPORT 65 16.25% 
2 SUPPORT I28 32% 
3 OPPOSE I36 34% 
4 STRONGLY OPPOSE 38 9.5% 
7 REF/ 8 DK/9 NA 33 8.25% 
400 100% 
TAX2 Would you strongly support, support, oppose, or strongly oppose additional funding 
from increased city fees, charges, or property taxes to fund a City street tree program? 
I STRONGLY SUPPORT 25 6.25% 
2 SUPPORT 15I 37.75% 
3 OPPOSE 132 33% 
4 STRONGLY OPPOSE 63 I5.75% 
7 REF/ 8 DK/9 NA 29 7.25% 
400 100% 
TAX3 Would you strongly support, support, oppose, or strongly oppose additional funding 
from increased city fees, charges, or property taxes to fund a more comprehensive tree 
planting and maintenance program in Tigard parks and open spaces? 
PROBE: This would include trees throughout Tigard, not just on streets. 
I STRONGLY SUPPORT 32 8% 
2 SUPPORT 190 47.5% 
3 OPPOSE I04 26% 
4 STRONGLY OPPOSE 53 I3.25% 
7 REF/ 8 DK/ 9 NA 2I 5.25% 
400 100% 
TAX4 Would you prefer volunteering to plant and maintain trees or paying a fee to the City 
to do this? 
PROBE: Even if you are not a property owner, which would you prefer? 
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City of Tigard Urban Forestry Code RcYisions I Volume V I 257 
Urban Forestry Master Plan Appendix I City of Tigard I 
APPENDIX A 
I PLANT 
2PAY 
3 IF VOL- NEITHER 
7 REF/ 8 DK/9 NA 
208 52% 
106 26.5% 
61 15.25% 
25 6.25% 
400 100% 
CHOICEl Which of the following would be your first choice of where the city should plant 
more trees? 
(PROBE FROM LIST) 
I ALONG STREETS 
2 IN PEOPLE'S YARDS 
3 IN COMMERCIAL/INDUSTRIAL AREAS 
4 IN PARKS 
5 NEAR STREAMS/NATURAL FORESTED AREAS 
7 REF/ 8 DK/9 NA 
99 
10 
51 
79 
129 
32 
400 
24.75% 
2.5% 
12.75% 
19.75% 
32.25% 
8% 
100% 
CHOICE2 Which of the followi ng statements most closely represents your opinion about 
trees. 
I PRESERVE AS MANY TREES AS POSSIBLE 
2 WHEN TREES ARE REMOVED, REPLACE THEM 
3 PRESERVE LARGE OR UNIQUE TREES 
4 ALLOW INDIVIDUALS REMOVE TREES IF WISH 
5 IF VOL- NONE OF THESE STATEMENTS 
7 REF/ 8 DK/9 NA 
128 
129 
60 
71 
I 
II 
400 
32% 
32.25% 
15% 
17.75% 
0.25% 
2.75% 
100% 
HAZARD Currently, if there is a dispute between neighboring property owners regarding a 
potentially hazardous tree, the City does not get involved, and instead directs the neighbors to 
work out a solution through civil means. Wou ld you strongly support, support, oppose, or 
strongly oppose the creation of a program where the City would become involved in disputes 
between neighbors regarding hazardous trees? 
I STRONGLY SUPPORT 54 13.5% 
2 SUPPORT 185 46.25% 
3 OPPOSE 101 25.25% 
4 STRONGLY OPPOSE 49 12.25% 
7REF/ 8DK/9NA II 2.75% 
400 100% 
City of Tigard !Jrban Forestry Survey - 2008 
- Top line Frequencies Page 12 
Cin· of Tigan.l Urban huc~tn· Code Rn· i ~ion~ I \'olumc \ ' I 25H 
City of Tigard I Urban Forestry Master Plan Appendix 
REG I Would you strongly support, support, oppose, or strongly oppose 
tree removal regulations during property development, even when they limit the size and 
extent of potential buildings or profits? 
I STRONGLY SUPPORT 59 14.75% 
2 SUPPORT 168 42% 
3 OPPOSE 99 24.75% 
4 STRONGLY OPPOSE 32 8% 
7REF/ 8DK/9NA 42 10.5% 
400 100% 
APPENDIX A 
REG2 If you had the opportunity to develop your property, would you be in favor of city tree 
regulations that required preservation of existing large trees and landscaping or tree planting 
afterwards? 
1 YES 
2NO 
3 IF VOL- IT DEPENDS 
7 REF/ 8 DK/9 NA 
264 66% 
97 24.25% 
14 3.5% 
25 6.25% 
400 100% 
REG3 Should the City allow the decision to preserve trees to be left to the developer? 
I YES 
2NO 
3 IF VOL - IT DEPENDS 
7 REF/ 8 DK/9 NA 
80 
293 
17 
10 
400 
20% 
73.25% 
4.25% 
2.5% 
100% 
REG4 If the City were to enact new tree protection measures, would you like to see them 
focused on natural areas, ornamental landscape trees, both types equally, or on something 
else. 
1 NATURAL AREAS 149 37.25% 
2 ORNAMENTAL TREES 11 2.75% 
3BOTH 192 48% 
4 SOMETHING ELSE 25 6.25% 
7 REF/ 8 DK/9 NA 23 5.75% 
400 100% 
REGS Would you strongly support, support, oppose, or strongly oppose city regulations that 
would provide some level of protection for large, healthy trees on developed private property? 
PROBE: This would apply to all current private property. 
I STRONGLY SUPPORT 78 19.5% 
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Topline Frequencies Page 13 -
City of Tigard Urban Forestry Code Re,·isions I Volume V I 259 
Urban Forestry Master Plan Appendix I City of Tigard 
APPENDIX A 
2 SUPPORT 
3 OPPOSE 
4 STRONGLY OPPOSE 
7 REF/ 8 DK/9 NA 
224 56% 
60 15% 
20 5% 
18 4.5% 
400 100% 
REG6 If the city were to enact new tree protection measures, where would you prefer to see 
them focused : on larger groves of native trees or individual trees of significant size. 
I LARGE GROVES 221 55 .25% 
2 INDIVIDUAL TREES 113 28.25% 
3 IF VOL- BOTH 31 7.75% 
4 IF VOL- NEITHER 18 4.5% 
7 REF/ 8 DK/9 NA 17 4.25% 
400 100% 
AGE In what year were you born? 
Coded Categories: 
AGE 18-24 3 0.75% 
AGE 25-34 23 5.75% 
AGE 35-44 59 14.75% 
AGE 45-54 106 26.5% 
AGE 55-64 91 22.75% 
AGE 65 AND OLDER 118 29.5% 
7 REF/ 8 DK/9 NA 0 0% 
400 100% 
GENDER Are you male or female? 
1 MALE 160 40% 
2 FEMALE 240 60% 
7 REF/ 8 DK/9 NA 0 0% 
400 100% 
RENT Do you own your home, or do you rent? 
I OWN 344 86% 
2 RENT 49 12.25% 
7 REF/ 8 DK/9 NA 7 1.75% 
400 100% 
Cit) of Tigard Urban Forestry Survey - 2008 
Topline Frequencies Page 14 
~~~~~~~~--------------------------------------------
City of Tigard Urban l;orcstn· Code Rc,-isions I \'olumc \ ' I 2(,() 
CityofTigard I Urban Forestry Master Plan Appendix 
APPENDIX A 
STREET What neighborhood do you live in? 
PROBE: What is your closest elementary school? 
PROBE: What is your closest cross street? 
OPEN ENDED- RECORD EXACT RESPONSE 
END That's the end of the survey! On behalf of the City of Tigard, we would like to thank 
you for your time and participation. Have a great day. Good bye. 
NOQAL I'm sorry, we can only interview residents of who are 18 years of age or older). I'm 
sorry to have bothered you. Have a nice (day/evening). 
City of Tigard Urban Forestry Survey- 2008 
Topline Frequencies Page 15 
----------------------------------------------1111111 
City o f Tigard Urban Forestry Code Re,·isions I Volume V I 261 
Urban Forestry Master Plan Appendix I City of Tigard 
APPENDIX B 
Canopy Change 
(1996 to 2007) 
-
a rtG~~s 
/3115 SW H all Bl<td 
Tigard , Orego n 91123 
503 . 639 . 4171 
www. tiga rd- or. go'f 
Legend 
- Canopy Lost 
- Canopy Gained 
- Canopy Preserved 
I [==:J Tigard C ity Limits 
Citywide Canopy Change Summary 
1996 2007 
Acres Perren t * Acres Perrent * 
Tigard's Total Canopy Cover 1952.75 25.84% 1852.69 24.52% 
* of June 2008 city limits 
....-~------------------------------
City of Tigard Urban I 'orcs try Code Rc,·isions I \ ' olumc \ ' I 2(,2 
[1996 [ 
WEII{f{O 
o CK H A N ST .~ 
Canopy Cluster 
Size Class 
Less thlll 0.5 aaes 
0.5 to .99 aaes 
1.0 to 1.99 aaes 
2.0 to 4.99 aaes 
5.0 or more aaes 
Total 
1996 
Total Aaes of Aaes as a Percent of 
a.topy Cover Total Canopy Cover 
366.55 18.77"/o 
135.76 6.95% 
159.25 8.16% 
190.86 9.77"/o 
1100.33 56.35% 
1952.75 roo•;. 
Canopy Clustering 
Legend 
Less than .5 
0.5 . 0.99 
1.0. 1.99 
2.0. 4.99 
5.0 or more 
UIH SW ,.hllll•d 
Tlrord, Or•r•" f7llJ 
JOJ . Uf . 4171 
Canopy Clustering Summary 
No. of Ousters No. of Clusters as Total Aaes of 
a Percent ofTotal a.topy Cover 
4356 90.94% 584.3 
197 4.11% 167.25 
113 2.36% 1.77.88 
61 1.27"/o 157 
63 1.32% 766.26 
4790 too•t. 1852.69 
2007 
Aaes as a Peramt of No. of Clusters Total Canopy Cover 
31.54% 7231 
9.03% 242 
9.60% 13 1 
8.47"/o 52 
41.36% 48 
100% 7704 
2007 
No. ofCiusters as 
a Peramt ofTotal 
93.86% 
3.14% 
I. 70% 
0.67% 
0.62% 
100% 
)> 
""0 
""0 
m 
z 
0 
>< 
OJ 
Urban Forestry Master Plan Appendix I City of Tigard 
APPENDIX B 
Canopy Change 
Within 1996 BLI 
( 1996 to 2007) 
fO 11GAil~ 
13/25 SW Hall Bhd 
Tltord , Ortton 9 7123 
SOJ . 639 4171 
www. r lrord.or. ro~ 
M-•1· c" .~ u ... ,5, :[)()~; 
• 
a a 
Legend ' ~  1 -~~ • 
- Canopy Lost 
- Canopy Gained 
c:::::::! Canopy Preserved 
C==:J 1996 Buildable Lands lnv 
..-----, 
T igard City Limits 
Citywide Canopy Change Within 1996 BLI Area Summary 
1996 2007 
Ao-es Perunt Aa·es Pen:en t Perunt Change 
Tigard's Canopy Co ver· within 1996 
BLI (1423.32 aa·es) 646.52 45.42% 495.24 34.79% -10.63% 
Citywide Canopy Cover Within BLI Summary 
1996 2007 
BLI Acres o f BLI Acres o f 
Acres Canopy Cover Perren t Acres Canopy Cover 
Tigard 's Canopy Cover within BLI 1423.32 646.52 45.42% 528.75 226.26 
Perren t 
42.79% 
..... r-------------------------------
City of T igan.l Urban Fores try Cock R, ,·isions I \ 'olumc \ ' I 2(> -1 
City of Tigard I Urban Forestry Master Plan Appendix 
Canopy By 
Property Ownership 
a -rJGAA~pS 
13125 SW Hall B htd 
Tlrard , Oreron 97223 
503 . 639 . 4/1 1 
www.11rard·ar. ro" 
MilrCtealed AlliJ"SII3 200P 
Legend 
c::::::::J City of Tigard 
c::::::::J Public Right-of-Way 
c::::::::J Other Public Entities 
r Private Land 
- Canopy Cover 
c::=J Tigard City Limits 
Canopy/ Property Ownership Summary 
M ay 13, 2008 Taxlots 2007 Canopy Cover 
Taxlot Ownership Number of Total Acres Acres of Canopy Percent Canopy 
Taxlots Cover in 2007 Cover in 2007 
CityofTigard 235 388.41 179.18 46.13% 
PublicRight-of-Way n/ a 1,288.30 117.45 9.12% 
Other PublicEntity 79 43 1.65 105.1 24.35% 
Private 15,880 5,447.64 1,450.96 26.63% 
Total 16,194 7,556.00 1,852.69 24.52% 
APPENDIX B 
------------------------------~ ..... 
City of Tigard Urban Forestry Code Re,-isions I Volume \' I 265 
Urban Forestry Master Plan Appendix I City of Tigard 
APPENDIX B 
.-- --------~ Canopy Change in Sensitive Lands (1996 to 2007) 
CWS FEMA 100 
Year Flood Plain 
CWS Vegetated 
Corridor 
Mflp Cn,,•fed AtJgust 200P 
Local Wetland 
Inventory 
I Slope > 25% I 
Tirord, Or~ ron 91113 
503 . 6 39 . 4 I 71 
www. t/fQfd - or.ro~ 
Citywide Canopy Change Within Sensitive Lands Summary 
1996 2007 
Sensit ive Canopy Perrell Perrelt o fl 996 Canopy Perrell Perrel t of l996 
Land Acres Acres Canopy Canopy Cover Acres Canopy Canopy Cover 
Load Wet land In ventory 290.91 145.98 50. 18% 7.48% 11 6.01 39.88% 6.26% 
CWS Vegetated Conidor 704.78 348.1 6 49.400/o 17.83% 302.85 42.97% 16.35% 
FE MA 100-yr Flood plain 592.6 213.1 7 35.97% 10.92% 188.05 31.73% 10.1 5% 
Slopes > 25% 195.5 1 130.28 66.64% 6.67% 129.64 66.3 1% 7.00% 
Total 1783.8 837-59 46.96% 42.89% 736.55 41.29% 39.76% 
Perren! Change 
-1 0.300/o 
-6.43% 
-4.24% 
-0.33% 
-5-66% 
..... ~-------------------------------
Cit}· of T igard Urban l;orcstn· Code Rc,·isions I \'olumc \ ' I 2o(, 
Canopy Change 
by Zoning 
(1996 to 2007) 
9 f)G~~~ApS 
13125 SW Hall 8/wd 
Tlrord, Oreton 91223 
503. 639 . 4171 
www. tlrard-or.rov 
MlpCwa/Qd Auyl.l!ll/13 200Q 
Legend 
- Canopy Lost 
- Canopy Gained 
- Canopy Preserved 
Zoning Type 
Residential 
c::J Tigard City Limits 
City of Tigard I Urban Forestry Master Plan Appendix 
APPENDIX B 
Citywide Canopy Change By Zoning Summary 
1996 2007 
I 
2008 Perrent 
Zoning Total Acres Acres Perrent Acres Perrent Change 
Commercial 800 88. 13 I 1.02% 80.52 10.07% -0.95% 
Ind ustrial 863 139.8 1 
I 
16.20"/o 137.58 15.94% -0.26% 
Mixed Use 701 150.3 21.44% 99.79 14.24% -7.21% 
Residential 5192 1574.42 30.32% 1534.72 29.56% -0.76% 
Total 7556 1952.66 25.84% 1852.61 24.52% -1.32% 
------------------------------~ ..... 
City of Tigard Urban l'orcstry Code Re,-isions I Volume V I 267 
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City of Tigard I Urban Forestry Master Plan Appendix 
APPENDIX B 
Parking Lot Sample Acreage : 508.77 acres 
Parking Lot Sample Acres covered by canopy: 30.72 acres 
Percent Parking Lot Sample Canopy Coverage: 6% 
________________________________ ...._ 
City of Tigard Urban Forestry Code Re,·isions I Volume V I 269 
Urban Forestry Master Plan Appendix I City of Tigard 
APPENDIX C 
Home Builder's Association of Metropolitan Portland Stakeholder Interview Notes 
I. What is your level of interaction with Tigard's urban forestry program? 
• The 1000+ members of the Home Builder's Association of Metropolitan Portland 
(HBAMP) rely on the homebuilding industry for their livelihood. It is in the interest of 
the membership to develop land and create building sites for new homes. Land 
development requires tree removal on sites that have trees and are zoned for 
development. 
• Applications for land development are currently required to include tree 
preservation/removal plans prior to development in order to meet Tigard Development 
Code requirements. 
• Under the current code section 18.790, applicants may pay a fee in lieu of mitigation or 
are required to mitigate tree removal by planting replacement trees within the City. 
• HBAMP members have attended Tree Board, Planning Commission, and City Council 
meetings to provide input on tree related matters such as the Urban Forest section of the 
Comprehensive Plan. 
• The HBAMP has a representative on the Urban Forestry Master Plan Citizen Advisory 
Committee. 
2. What features of Tigard's urban forestry program work well? 
• Tree planting when the right tree is planted in the right place. 
• The City's overall goal of preserving trees. 
• Requiring developers to utilize the expertise of independent, certified arborists when 
evaluating the conditions of trees and their viability of survival with site development. 
3. What features of Tigard's urban forestry program do not work well, and why? 
• The HBAMP's position is that the City's mitigation requirements are unreasonable and 
punitive. 
• The mitigation structure in section 18. 790.030.B.2 (a-d) is unreasonable because it is 
not practicable to retain even 25% of the trees on sites zoned for medium to high 
density residential development (5 units per acre or more) . There has likely never been 
a development in Tigard with 75% or greater retention on property zoned R4.5 or 
higher. Heavy equipment, grading, roads, and utilities are very disruptive to trees. 
Significant amounts of grading must take place outside the right of way when driveways 
are cut in , sidewalks are poured, and building footprints are cleared for structures. 
This results in tree retention being limited to the perimeter of developed sites. 
• The City's current program incentivizes the preservation of trees that wiU cause potential 
future hazards. For example, trees over 12" in diameter have root systems and 
canopies that extend at least 10' from the trunk. Larger trees have larger areas around 
them that need to remain undisturbed. This is not practicable is high density situations . 
....---------------------------------
Cit}· orTi~o>a rd Urban l;on:>try Code Rc,·ision> I \ 'olume \ ' I 270 
CityofTigard I Urban Forestry Master Plan Appendix 
Even if a younger but potentially large tree species such as Doug.-fir is able to be 
retained, it often makes sense to remove it to avoid potential hazards in the future. 
• The fee structure associated with fee in lieu of planting for mitigation far exceeds the 
actual cost to plant trees. For example, a recent mitigation project to plant trees in 
Cook Park for the Fletcher Woods development cost the developer $20,000 to complete. 
However, the City required the developer to submit a bond for $106,000 or $110 per 
caliper inch as assurance and to cover the City's cost of planting should the developer 
fail to mitigate. 
• The incentives in section 18.790.040 should be updated. For example, the density 
bonus incentive allows for a 1% density bonus for 2% canopy cover retained. This 
bonus does not yield any practical benefit unless the site is very large. For a site that is 
10 lots, it would take 20% retention for a 10% density bonus to add just one unit. 
Moreover, by adding another unit and decreasing the amount of land available for 
infrastructure and buildings, the result is lots that are significantly smaller than zoning 
allows. This creates a direct conflict with lot size requirements in section 18.510. 
• Finally, it is the consensus of the HBAMP that tree regulation and tree plan requirements 
require additional resources adding cost and time to any development project. In 
addition, Tigard's current program is divisive and creates legal conflicts in the form of 
appeals to the Land Use Board of Appeals for tree related issues. 
4. What could be done in the future to improve the programs that do not work well? 
• The City should not regulate trees on private property. Private property owners should 
be allowed to cut trees as they have done since the establishment of Tigard. This "hands 
off'' approach has successfully been done for decades with virtually no loss (and 
perhaps even some gain) in tree canopy. Trees are not community property and belong 
to the owners of the land. 
• Eliminate the punitive standards that cost developers large sums of money for 
unavoidable tree removal. There is currently over $1,000,000 in the tree mitigation 
fund. It is expected to grow to over $2,000,000 within the next year. This fund can only 
be used to plant trees. Last year's City budget for tree planting was $50,000. There is 
little available land within the City where future trees can be planted. 
• If the City does continue to regulate trees in the future, developers should only be 
required to mitigate only for unnecessary tree removal. 
• The City should not incentivize the preservation of potentially hazardous trees. 
• The mitigation fee in lieu should be revised to reflect the actual cost of planting trees. 
• Revise incentives to create higher motivation for developers to utilize the incentives. 
• The City forestry program should be balanced with the right to subdivide and develop 
private property. The cost of an urban forestry program should not outweigh the 
benefits. 
5. How can we work together in the future to improve Tigard's urban forest? 
APPENDIX C 
------------------------------~....-
City of 'figard Urban Forestry Code Re,·isions I Volume V I 271 
Urban Forestry Master Plan Appendix I City of Tigard 1 
APPENDIX C 
• HBAMP and its members continue to participate in the public process so that their views 
are understood by the City's decision makers. 
• It is the view of those HBAMP members who have participated in the process that the 
HBAMP's views are dismissed while the views of the Tree Board and one extremely 
active Tigard citizen are taken very seriously. It is always simple to achieve "consensus" 
when everyone in the room shares the same view. The key to real and balanced 
stakeholder participation is to find the people who have concerns about the forestry 
program and openly discuss the views of the stakeholders ' concerns and have dialogue. 
The HBAMP has received virtually no feedback from City staff, the Tree Board or the 
Citizen Advisory Committee about the information and testimony HBAMP's 
representatives have provided at meetings, public hearings and worksessions. This 
needs to be addressed. 
• By requiring costly tree mitigation and/or fees for tree removal, it is the view of the HBA 
members who have been involved in this process that the Tree Board and City Staff are 
putting the interest of trees ahead of the interest of property owners. This is 
unacceptable. 
• City staff has not made a concentrated effort to contact those property owners who have 
the most potential impact under the current and future tree code. These owners should 
be contacted and advised of the financial impact the current tree code could have on 
their property values. These are the single most impacted stakeholder group, yet they 
have never been invited to any meetings. This needs to be addressed. 
6. What should be included/excluded from Tigard's urban forestry programs? 
• There should be no urban forestry program because the benefits of such a program do 
not outweigh the costs. 
• Do not regulate trees on private property, and allow owners to manage their land as they 
see fit. 
• However, if the City does continue to regulate trees in the future the following should be 
included/excluded from the program: 
o Eliminate punitive mitigation standards and only require developers to mitigate 
for unnecessary tree removal. 
o Revise fee in lieu of mitigation to reflect the actual cost of tree replacement. 
o Do not incentivize the preservation of large and potentially hazardous trees. 
o Revise incentives for tree preservation so that developers are able to utilize the 
incentives. 
o Make a concerted effort to include the HBAMP and affected property owners in 
the process. 
Clean Water Services Stakeholder Interview Notes 
I. What is your level of interaction with Tigard's urban forestry program? 
....-~------------------------------
Ciry of Tigard Urban l;orcs try Code Rc,·isions I \ 'olumc \ . I 272 
City of Tigard I Urban Forestry Master Plan Appendix 
• Watershed Management Department manages revegetation projects in Tigard's stream 
corridors. 
• Partnered with urban forester (currently unfilled) on many acres of tree planting in 
Tigard's stream corridors including Englewood Park, Fanno Creek Park, and Cook 
Park. These projects were funded by Surface Water Management (SWM) fees which 
come from sewer system ratepayers. 
• Development Services issues Service Provider Letters (SPL) for development projects 
with potential impacts on stream corridors. 
• CWS inspectors monitor Vegetated Corridor work of private developers to ensure 
compliance with CWS standards. 
• Some stream restoration projects require City of Tigard tree removal permits and tree 
protection plans. 
2. What features of Tigard's urban forestry program work well? 
• Tigard Public Works is effective at using volunteers for planting projects. 
• In theory, the tree mitigation fund works well (if the money is actually used for tree 
planting). 
• Tigard has worked well with Clean Water Services on tree planting projects and meeting 
"Tree for All" planting goals. 
3. What features of Tigard's urban forestry program do not work well, and why? 
• Tree survey requirements can be counterproductive for restoration projects in stream 
corridors. The money for tree surveys and protection plans in areas dominated by non-
native or invasive trees would be better spent on tree planting. 
• Invasive and non-native trees in Sensitive Areas and Vegetated Corridors should not be 
protected and/or require a tree removal permit. Protecting invasives and non-natives is 
a barrier to restoration. 
• Vegetated Corridor and other natural area plantings require long term maintenance 
beyond the two-year maintenance period typically required of developers. 
4. What could be done in the future to improve the programs that do not work well? 
• The City should be more diligent about taking a proactive approach to inspecting 
Vegetated Corridors during the maintenance period if their Urban Forestry Program 
includes CWS Vegetated Corridor requirements. 
• Restoration projects in degraded Sensitive Areas and Vegetated Corridors should be 
exempt from tree survey and protection requirements. 
• Tigard needs to adopt an inclusive invasive species list and exempt the removal of 
invasive trees from Sensitive Areas and Vegetated Corridors from permit requirements. 
• There needs to be more focus on long term maintenance of private and public riparian 
plantings. This could be addressed through a combination of Code requirements, SWM 
APPENDIX C 
_______________________________ ...._ 
City of Tigard Urban Fores try Code Rc,·isions I Volume V I 273 
Urban Forestry Master Plan Appendix I City of Tigard 
APPENDIX C 
funds, and tree mitigation funds. The City should secure a stable source of funding for 
vegetation maintenance. 
5. How can we work together in the future to improve Tigard's urban forest? 
• Continue stewardship of "Tree for All" sites even after the program ends. 
• Coordinate pubtic outreach about invasive plants and the responsibitities of streamside 
property owners. 
• Ensure City of Tigard and Clean Water Services regulatory requirements are coordinated 
in future. Allow Clean Water Services to review/comment on Code changes that affect 
stream corridors prior to adoption. 
• Continue partnering to co-implement Stormwater Management Permits. 
• Coordinate on implementing an integrated pest management plan. 
6. What should be included/excluded from Tigard's urban forestry programs? 
• Exempt stream restoration projects in degraded Sensitive Areas and Vegetated Corridors 
from tree survey and protection requirements. 
• Exempt invasive and non-native tree removal in stream corridors from permit 
requirements. 
• Adopt an inclusive invasive species Ust and exempt invasive tree removal from permit 
requirements. 
• Focus on long term maintenance of riparian plantings through Code revisions, SWM 
funds, and tree mitigation funds. 
• Secure a stable funding source for long term riparian vegetation management. 
• Monitor expenditure of SWM funds to ensure that adequate funding is provided for 
riparian vegetation management. 
• Fill the urban forester position so that riparian revegetation projects continue/expand in 
the future . 
• Coordinate City planting standards in stream corridors with Clean Water Services 
standards. 
• Implement an Integrated Pest Management (IPM) Plan in cooperation with Clean Water 
Services. 
Oregon Department of Transportation Stakeholder Interview Notes 
I. What is your leve_l of interaction with Tigard's urban forestry program? 
• During development, the Oregon Department of Transportation ( ODOT) reviews street 
tree planting plans in ODOT right of ways for comptiance with ODOT specifications. 
• ODOT reviews and grants permHs for City tree planting projects in ODOT right of ways 
(99W, Hall Boulevard, Highway 21 7). 
- ----------------
Cin· ofTigarJ Urban l'ore>tn· CoJc Rc,·i>ions I \ 'olume \ ' I 274 
City of Tigard I Urban Forestry Master Plan Appendix 
APPENDIX C 
2. What features of Tigard's urban forestry program work well? 
• No comment. 
3. What features of Tigard's urban forestry program do not work well, and why? 
• Street tree planting under powerlines causes conflicts because traffic lanes are closed 
for ongoing maintenance issues. 
• Some trees cause damage to infrastructure (sidewalks, curbs, streets). 
• Trees planted on top of underground utilities cause future conflicts due to root 
interference. 
• Some City tree planting and placement requirements are not coordinated with ODOT 
requirements (root barriers, site distance, clear distance, limb clearance) 
4. What could be done in the future to improve the programs that do not work well? 
• Require overhead utilities to be shown on site plans to avoid inappropriate tree planting 
that will create future conflicts. Route plans to Portland General Electric for review. 
• Select street trees that will not conflict with hard features . Require root barriers and 
other design feature that will help to minimize conflicts. 
• Require development projects to locate utilities on planting plans prior to ODOT and 
City review. This help to ensure that trees are not planted on top of existing utilities. 
• Clarify jurisdictional requirements and coordinate during future Code updates. 
5. How can we work together in the future to improve Tigard's urban forest? 
• Clarify jurisdictional requirements and coordinate during future Code updates. 
6. What should be included/excluded from Tigard's urban forestry programs? 
• Prohibit the planting of trees that will conflict with powerlines. Route plans to Portland 
General Electric for review. 
• Require root barriers and other design feature that will help to minimize conflicts with 
hard features . 
• Require development projects to locate utilities on planting plans prior to ODOT and 
City review. 
• Clarify jurisdictional requirements in ODOT right of ways: 
o ODOT site distance requirements supersede Tigard requirements. 
o ODOT clear distance requirements supersede Tigard requirements. 
o ODOT branch clearance requirements supersede Tigard requirements. 
o ODOT has final sign off authority on any trees planted or removed in ODOT right 
of way ( ODOT permit required) . 
------------------------------~ ..... 
City of Tigard Urban Forestry Code Re,·isions I Volume V I 275 
Urban Forestry Master Plan Appendix I City of Tigard i 
APPENDIX C 
The Parks and Recreation Advisory Board Stakeholder Interview Notes 
The Parks and Recreation Advisory Board declined to comment at their February 23, 2009 meeting. 
Pm1land General Electric (PGE) Stakeholder Interview Notes 
1. What is your level of interaction with Tigard's urban forestry program? 
• PGE continually trims trees away from overhead conductors in Tigard to provide for the 
safe, reBable and continual source of electricity to meet the needs of commercial and 
residential customers. 
• PGE considers the City of Tigard an integral participant in this process in terms of 
establishing approved street tree lists, encouraging appropriate and responsible 
plantings, approving of ideal specimens for their heritage tree program and having the 
long term vision to develop and maintain an urban forestry program. 
2. What features of Tigard's urban forestry program work well? 
• As a whole, Tigard's urban forestry program works extremely well. There is very 
qualified and attentive stewardship of trees in the City of Tigard. 
3. What features of Tigard's urban forestry program do not work well , and why? 
• Some inappropriate street tree plantings in the City of Tigard. 
• Several potentially hazardous tree/utility conflicts in the City of Tigard. 
4. What could be done in the future to improve the programs that do not work well? 
• Remove and replace inappropriate street trees. 
• Aid in the hazardous tree removal by providing the labor and equipment necessary. 
5. How can we work together in the future to improve Tigard's urban forest? 
• PGE can contribute appropriate trees to new planting sites. 
• Aid in hazardous tree removal where the threat of an overhead conductor is a factor. 
• Attend monthly City coordination meetings. 
• Share in the exchange of information and of past experiences of what works well and 
what doesn't work quite well in other municipalities. 
• Assist in any educational capacity such as right tree/right place programs. 
6. What should be included/excluded from Tigard's urban forestry programs? 
....-~------------------------------
Cin· ofTigan.l Urban l'orc,try Code Rc,·i, iom I \'olumc \ ' I '276 
City of Tigard I Urban Forestry Master Plan Appendix 
• Future programs need to recognize the conflict between a static overhead distribution 
system of electricity and the dynamic nature of vegetation management around PGE 
facilities. 
• Invite PGE to monthly City coordination meetings. 
• Route tree plans to PGE for review. 
Pacific Northwest Chapter of the International Society of Arboriculture Stakeholder Interview Notes 
1. What is your level of interaction with Tigard's urban forestry program? 
• High level of involvement with tree ordinance through development projects. 
• Assist private property owners with tree management outside the development process. 
2. What features of Tigard's urban forestry program work well? 
• Tree code helps to incentivize preservation because increasing tree removal requires 
increasing mitigation and associated costs. 
• Bi-weekly arborist report condition of approval helps to ensure better project oversight 
and tree plan implementation. 
3. What features of Tigard's urban forestry program do not work well, and why? 
• Tree code penalizes property owners with heavily treed lots more than those with un-
treed lots. Mitigation is tied solely to tree removal. This may have the effect of 
precluding development in heavily treed areas such as the Tigard Triangle that are 
zoned for dense development. 
APPENDIX C 
• Mitigation standards encourage overplanting of trees or planting of small stature trees to 
meet mitigation requirements. Requiring tree replacement on a caliper inch basis may 
not be appropriate for every tree and contributes to overplanting. 
• No sustainable funding for urban forestry programs. There needs to be a stable funding 
source for Tigard's urban forestry program that can be utilized for tree maintenance, 
not just tree planting. 
• Bi-weekly arborist reports can be hard for the City to track, especially during the 
transition from site development to building phase. 
• Project arborists are hired to protect their clients. This can result in arborist reports 
with false or misleading information. 
4. What could be done in the future to improve the programs that do not work well? 
• Determine tree stocking levels based on plantable areas as is done in the City of 
Vancouver, WA. This could be accomplished by matching available soil volumes for lots 
of various sizes with trees. 
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APPENDIX C 
• Allow required trees such as parking lot and street trees to count for mitigation. This 
will help alleviate overplanting of mitigation trees. 
• Provide incentives for planting of natives and large stature mitigation trees. One 
incentive could be to offer more mitigation credit for planting natives and large stature 
trees. This will help alleviate overplanting and encourage the planting of trees that offer 
the most environmental benefits. 
• Develop spacing standards based on the mature size of trees to improve long term 
growth and health . 
• Urban forestry funding can be more sustainable if it tied to stable sources such as 
stormwater fees , permit fees , transportation fees, etc. This will also allow for the urban 
forestry funds to be used for long term tree maintenance. 
• Bi-weekly arborist reports should be required in future code updates. The City should 
require a copy of the contract for bi-weekly reports and require the project arborist to 
send a notice to the City if the contract is terminated. If a different arborist is to provide 
bi-weekly reports, then the original project arborist should have to sign off prior to the 
new arborist amending the tree preservation plan. 
• The City should require more personal accountability for project arborists to discourage 
false or misleading information. Measures could include revoking business licenses 
and/or fines so that project arborists have more personal accountability when providing 
false or misleading information. 
• An alternative method to limit false or misleading reports would be for the City to hire a 
third party the arborist to do the tree preservation report and bi-weekly inspections. 
5. How can we work together in the future to improve Tigard's urban forest? 
• ISA can provide input and review on future tree code revisions. 
• ISA can be a resource for code provisions that have been successful in other 
jurisdictions and may be appropriate for Tigard. 
6. What should be included/excluded from Tigard's urban forestry programs? 
• Require mitigation based on stocking levels, not on a caliper inch basis. 
• Develop clear and specific mitigation requirements that favor native and large stature 
trees, and require spacing per industry standards. Allow required landscape trees and 
street trees to count towards mHigation requirements. 
• Do not unfairly penalize property owners with heavily treed lots that will have trees that 
are overcrowded and not in good condition. 
• Incentivize protection and replanting of natives and large stature trees. 
• Identify sustainable funding sources for urban forestry programs. Fund long term 
maintenance of trees, not just tree planting. 
• Require project arborists to be brought onto the project team as early as possible. 
• Allow the project arborist to drive the tree preservation plan in future code updates, not 
the project engineer. 
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• Require metal fencing in future code updates. 
• Develop a zone of clearance for building footprints , and don 't penalize developers for 
removing trees in clearance zones. This zone could be 5' -1 0' or 3 to 5 times the 
diameter of the tree. However, site and species characteristics should be considered 
when crafting code revisions. 
• Increase planting strip size and require root barriers to protect streets and sidewalks. 
• Require utilities to be under the street, not in the planter strip where trees should be. 
• Hire a greenspace coordinator to manage the City's greenspaces. 
Tigard Area Chamber of Commerce Stakeholder Interview Notes 
APPENDIX C 
On March 9, 2009, I spoke with Christopher Zoucha, Chief Executive Officer of the Tigard Area Chamber 
of Commerce regarding the Urban Forestry Master Plan. Christopher informed me that urban forestry 
has not been an issue for the Chamber members, and therefore declined providing input as a 
stakeholder group for the Urban Forestry Master Plan. 
Tree Board Stakeholder Interview Notes 
1. What is your level of interaction with Tigard's urban forestry program? 
• The Tree Board is an oversight body for Tigard's urban forestry program. 
2. What features of Tigard's urban forestry program work well? 
• The City actively works to include the greater community in developing its urban forestry 
program. 
• The City collects substantial fees to be used for the planting of trees. 
3. What features of Tigard's urban forestry program do not work well, and why? 
• The City's departments are not well coordinated on urban forestry issues due to lack of 
communication. 
• Tree management provisions are scattered throughout the Code and not unified. 
• The Tree Code is too focused on development. 
4. What could be done in the future to improve the programs that do not work well? 
• More communication between City departments. 
• Unify tree related provisions in Code. 
• Focus future Code on areas outside development, and fix the mitigation issue. 
5. How can we work together in the future to improve Tigard's urban forest. 
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• The Tree Board can help create a plan for the future management of Tigard's urban 
forest. 
• The Tree Board can help execute the action measures in the plan. Mitigation funds can 
be used to implement the plan. 
• The Tree Board can continue to reach out to stakeholders when implementing the plan. 
6. What should be included/excluded from Tigard's urban forestry programs? 
• Increase communication between City departments. 
• Unify tree related Code provisions. 
• Focus future Code revisions on areas outside development. 
• Make sure Code revisions can be translated into something the public can understand. 
• Expand community education on urban forest!)' issues. Use Eastmoreland outreach 
materials as a model. 
• Continually measure progress on canopy preservation/expansion and community 
attitudes. 
• Plan for future annexations of tree resources in areas outside of the City limits. 
Oregon Chapter of the American Society of Landscape Architects Stakeholder Interview Notes 
1. What is your level of interaction with Tigard's urban forestry program? 
• High level of familiarity with Tigard's tree and landscape ordinances. 
• Regularly implements codes during development projects to meet landscape and 
mitigation requirements. 
2. What features of Tigard's urban forestry program work well? 
• Tigard actually has a tree and landscape ordinance whereas some cities do not. 
• Tigard staff is easily accessible to discuss issues with and work out solutions. 
• The Urban Forestry Master Plan will result in a more comprehensive approach to future 
tree and landscape ordinance updates. 
3. What features of Tigard's urban forestry program do not work well, and why? 
• Replanting on a caliper inch basis does not work because it incentivizes overplanting. 
• Site planning is focused too heavily on building needs and not on existing site 
conditions. This causes an excessive amount of clear cutting. 
• Landscape architects do not have enough flexibility in landscape design because 
landscape code requirements are overly specific. 
• Street tree list is outdated, and many of the species are no longer appropriate or 
relevant. 
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• Street trees and streetscapes are non-unifonn. Different development projects choose 
different types of trees so city blocks become a hodgepodge of street trees. 
APPENDIX C 
• Many parts of the tree code are overly vague, which creates loopholes and a wide variety 
of interpretations. For example, there are no spacing, species, or nursery stock quality 
standards with respect to mitigation trees. 
• Need more tree and landscape related expertise on the Tree Board. 
4. What could be done in the future to improve the programs that do not work well? 
• Focus tree code revisions on preservation and less on mitigation. If preservation 
requirements are increased, then mitigation could occur on a tree for tree basis rather 
than inch for inch. 
• Need to be stricter on grading with respect to trees. This can occur by focusing more 
on existing conditions and how trees can be incorporated into the building design. 
Also, landscape architects should be required to collaborate more with project arborists 
in order to identify which trees are appropriate for preservation, and how to adjust 
grading to preserve trees. Perhaps there should be a dual sign off on preservation plans 
between the landscape architect and project arborist. 
• Allow for more flexibility in landscape requirements in future updates. Require 
landscape architects to be part of the design team, and sign off on planting before, 
during, and after installations. 
• Update street tree list. 
• To improve uniformity of streetscapes, the developers should have to survey the street 
trees in a 4-5 block radius and choose trees that complement existing plantings. 
• The tree/mitigation code sections need more specificity. The City of Salem has a 
detailed development design handbook with detailed drawings and specifications that 
are referred to in their development code. This allows for more clarity as to what is 
expected of the development. 
• When advertising Tree Board vacancies, specify that you are looking for members with 
tree and landscape expertise. Advertise vacancies with local professional organizations. 
5. How can we work together in the future to improve Tigard's urban forest? 
• Sends drafts of tree and landscape code revisions to ASLA for review and comment. 
• Contact ASLA to see if members could get credit hours for developing codes and design 
handbooks. 
• Hire ASLA members to help develop code and design guidelines. 
• Share example codes that require maximum preservation of existing trees. 
6. What should be included/excluded from Tigard's urban forestry programs? 
• More focus on preservation through improved grading plans, less focus on mitigation. 
The City needs to take a leadership role in this. 
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APPENDIX C 
• More focus on sustainable landscapes. Not necessarily native trees, but trees that are 
appropriate for site conditions. 
• Need detailed design/preservation manual with illustrations. 
• Need to have a warranty period for required landscaping to ensure establishment. 
• Need to require powerlines to be shown on landscape plans to avoid future overhead 
utility conflicts. 
• Landscape architects should be a required member of the design team. 
Tigard Tualatin School District Stakeholder Interview Notes 
1. What is your level of interaction with Tigard's urban forestry program? 
• Somewhat limited. 
• Participation in the Tigard Neighborhood Trails Study. 
• Manage trees on School District property. 
2. What features of Tigard's urban forestry program work well? 
• Adequate budget for tree planting and early establishment. 
• City of Tigard is very cooperative with the School District. 
3. What features of Tigard's urban forestry program do not work well, and why? 
• Lack of communication prior to planting trees on School District property. It is 
important to coordinate with Facilities Division so that long term maintenance issues 
can be addressed prior to planting. 
4. What could be done in the future to improve the programs that do not work well? 
• Bring Facilities Division into the planning process from the beginning of a tree planting 
project. 
5. How can we work together in the future to improve Tigard's urban forest? 
• School District properties may offer opportunities to utilize City tree planting funds. 
• Wetlands on School District properties may offer wetland mitigation opportunities for 
the City. 
• Facilities Division would be able to provide guidance as to the types of trees and planting 
layouts that wiU facilitate long term maintenance by the District. 
• School District can contact City Arborist to find out if permits are required for tree 
removal and/or planting. 
6. What should be included/excluded from Tigard's urban forestry programs? 
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City of Tigard I Urban Forestry Master Plan Appendix 
• Bring Facilities Division into the planning process from the beginning of tree planting 
projects on School District properties. 
APPENDIX C 
• Focus on low maintenance plantings with evergreens and other trees with low leaf litter. 
Tualatin Riverkeepers Stakeholder Interview Notes 
1. What is your level of interaction with Tigard's urban forestry program? 
• High level of involvement. 
• Work closely with the City and Metro on restoration projects in Tigard. 
• Provide comments on municipal separate storm sewer systems (MS4) permits. 
• Provide comments on City of Tigard Parks plans and occasionally on private 
development applications. 
• Participated in the development of the Healthy Streams Plan by Clean Water Services. 
• Member of Oregon Community Trees, a non-profit organization that promotes urban 
and community forestry in Oregon. 
2. What features of Tigard's urban forestry program work well? 
• Mitigation fee structure provides an adequate budget for tree planting. 
3. What features of Tigard's urban forestry program do not work well, and why? 
• Trees could be better utilized for stormwater management in developed areas such as 
along street and in parking lots. 
• Urban forestry funds could be collected and utilized more strategically. An example 
would be to use stormwater management fees to fund restoration programs. 
• The City of Tigard could make more of a public commitment to sustainability efforts 
such as by sigrung the Mayor's Climate Protection Agreement. 
4. What could be done in the future to improve the programs that do not work well? 
• Improve parking lot design standards to incorporate stormwater treatment features and 
more tree canopy. 
• Retrofit existing parking lots to improve stormwater treatment and tree canopy using 
grant money and other funding sources. 
• Encourage/require the use of more evergreen species in parking lots and streets so that 
the stormwater benefits of trees can be utiltized during the winter rainy season. 
• Collect urban forestry funds more strategically through stormwater fees, development 
fees, etc. so that the funding sources are more sustainable and can be used for more 
than just tree planting. 
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APPENDIX C 
5. How can we work together in the future to improve Tigard's urban forest? 
• Tualatin Riverkeepers can assist with volunteer recruitment for urban forestry projects. 
• Tualatin Riverkeepers can help educate kids about the importance of environmental 
stewardship through camp and recreation programming. 
• Tualatin Riverkeepers can help identify potential restoration sites. 
• Tualatin Riverkeepers can provide training to Planning Commission, City Council , City 
staff, and others on low impact development techniques. 
6. What should be included/excluded from Tigard's urban forestry programs? 
• Improve parking lot design standards to incorporate stormwater treatment and more 
tree canopy. 
• Increase stormwater incentives/requirements for development such as the "no runoff' 
provisions as in Lacey Washington. 
• Collect urban forestry funds more strategically through stormwater fees, development 
fees, etc. so that the funding sources are more sustainable and can be used for more 
than just tree planting. 
• More public commitment to sustainability efforts such as signing the Mayor's Climate 
Protection Agreement. 
• More efforts in invasive species removal. Incentivize and/or require plivate landowners 
to remove invasives . 
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APPENDIX D 
City of Tigard Internal Coordination Meeting Results 
On January 21 , 2009, a coordination meeting was attended by key City staff members that have a role in 
coordinating and implementing Tigard's urban forestry programs, policies, and ordinances. Meeting 
attendees included representatives from a range of City departments (Community Development, Public 
Works, and Financial and Information Services) and divisions (Capital Construction & Transportation, 
Current Planning, Development Review, Information Technology, Public Works Administration, Parks, 
Streets, Wastewater/Storm, and Water) . The purpose of the meeting was to discuss urban forestry 
coordination issues, and identify those areas where coordination could be improved. As a result of the 
meeting, the following list was generated that identified areas where urban forestry coordination efforts 
could be improved. 
1. Street trees on record drawings don't reflect where they are actually planted (Planning, Engineering, 
Public Works, IT/GIS) ; 
2. Development engineering inspects vegetated corridors after development, but no long 
term/sustained maintenance requirements (Engineering, Planning/Arborist and Code Enforcement, 
IT/GIS) ; 
3. Difficult to track deed restricted trees after development (Planning, IT/GIS) ; 
4. Difficult to track required landscape trees (parking lot trees, buffer trees, etc.) after development 
(Planning/ Arborist and Code Enforcement, IT/GIS) ; 
5. Difficult to track mitigation trees after development (Planning/ Arborist, IT/GIS) ; 
6. No inventory of street trees (Planning, Engineering, Public Works, IT/GIS) ; 
7. When City acquires greenspaces, no detailed understanding of maintenance costs (especially 
regarding hazard trees) (Planning/Arborist, Public Works) ; 
8. No policy for protecting deed restricted trees and significant habitat trees during building additions 
(Planning, Building) ; 
9. No policy of requiring exempt City projects to follow standards required by private development 
(Planning, Capital Construction and Transportation, Public Works) ; 
10. No review of exempt City projects for trees by planning staff (Planning, Capital Construction and 
Transportation, Public Works); 
11 . No formal hazard evaluation process for parks/green spaces (Planning/ Arborist, Public 
Works/Parks, Risk) ; 
12. No formal emergency response system for tree hazards on streets (Planning/Arborist, Public 
Works/Streets) ; 
13. No formal emergency response system for tree hazards in parks/greenspaces (Planning/Arborist, 
Public Works/Parks) ; 
14. Tree removal in sensitive lands requires tree removal permits, not sure if there is awareness of this 
Code provision (Planning, Capital Construction and Transportation, Public Works) ; 
15. No formal process for spending/tracking tree mitigation fund expenditures and planting 
(Planning/Arborist, Public Works, IT/GIS, Finance) ; and 
16. No formal process for determining adjustments to street standards to preserve trees 
(18.810.030.A. 7) (Planning/Arborist, Engineering) . 
17. No formal street tree maintenance process for limb/root clearance and removal (Planning/Arborist, 
Public Works/Streets) . 
After the list was generated, a series of meetings was held with representatives from the groups affected by 
the coordination issues. The purpose of the smaller group meetings was to discuss the coordination issues 
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APPENDIX D 
and formulate possible solutions that could improve coordination efforts. The following Hst identifies 
possible solutions for the coordination issues that were formulated after the group meetings. 
1. Street trees on record drawings don't reflect where they are actually planted (Planning, Engineering, 
PubHc Works, IT/GIS) ; 
• Make note on record drawings that actual street tree locations may vary, see street trees in 
GIS for actual locations. 
• Require developers to GPS or pay a fee to the City to GPS actual locations of street trees 
prior to final approval. The spatial data can then be loaded into the City's GIS system for 
tracking. 
• Information on street trees to include location (x/y coordinates) , size (db h), species, date 
planted, condition, tree ID code, and any additional information necessary to conduct 
resource analyses in the future. 
• Consider creating program where developers pay a fee to the City to plant and GPS street 
trees. 
2. Development engineering inspects vegetated corridors after development, but no long 
term/sustained maintenance requirements (Engineering, Planning!Arborist and Code Enforcement, 
IT/GIS); 
• Development engineering inspects vegetated corridors after planting, and after a defined 
maintenance period (usually two years) to ensure compHance with Clean Water Services 
(CWS) requirements. 
• If the vegetated corridor becomes City property, then the Wastewater/Storm Division of 
PubHc Works assigns crews to ensure long term maintenance. 
• If the vegetated corridor is privately owned, the City of Tigard does not currently have a 
program to inspect/enforce long term vegetation maintenance. The City will clarify with 
CWS what agency is responsible for ensuring long term maintenance of vegetated corridors. 
3. Difficult to track deed restricted trees after development (Planning, IT/GIS) ; 
• Require developers to GPS or pay a fee to the City to GPS locations of deed restricted trees 
prior to final approval. The spatial data can then be loaded into the City's GIS system for 
tracking. 
• Information on deed restricted trees to include location (x/y coordinates) , size (db h) , 
species, date inventoried, condition , tree ID code, and any additional information necessary 
to conduct resource analyses in the future. 
4. Difficult to track required landscape trees (parking lot trees, buffer trees, etc.) after development 
(Planning!Arborist and Code Enforcement, IT/GIS) ; 
• Require developers to GPS or pay a fee to the City to GPS actual locations of required 
landscape trees prior to final approval. The spatial data can then be loaded into the City's 
GIS system for tracking . 
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APPENDIX D 
• Information on required landscape trees to include location (x/y coordinates) , size (db h) , 
species, date planted, condition, tree ID code, and any additional information necessary to 
conduct resource analyses in the future . 
5. Difficult to track mitigation trees after development (Planning/Arborist, IT/GIS) ; 
• Require developers to GPS or pay a fee to the City to GPS actual locations of mitigation trees 
prior to final approval. The spatial data can then be loaded into the City's GIS system for 
tracking. 
• Information on mitigation trees to include location (x/y coordinates) , size (db h) , species, 
date planted, condition, cash assurance/bond release date, tree ID code, and any additional 
information necessary to conduct resource analyses in the future. 
6. No inventory of street trees (Planning, Engineering, Public Works, IT/GIS) ; 
• Require developers to GPS or pay a fee to the City to GPS actual locations of street trees 
prior to final approval. The spatial data can then be loaded into the City's GIS system for 
tracking. 
• Hire AmeriCorps member and/or recruit volunteers to assist in inventory of existing street 
trees outside development process. 
• GPS actual locations of street trees planting during annual street tree planting program. 
• Information on street trees to include location (x/y coordinates), size (dbh), species, date 
planted, condition, tree ID code, and any additional information necessary to conduct 
resource analyses in the future. 
• Consider creating program where developers pay a fee to the City to plant and GPS street 
trees. 
7. When City acquires greenspaces, no detailed understanding of maintenance costs (especially 
regarding hazard trees) (Planning/Arborist, Public Works); 
• Create budget sheet to track personnel, material, and service costs associated with 
greenspace acquisition. 
• Budget sheet should detail first year costs as well as costs for years two through five. 
• A benefits section should be included on the form to identify mitigation, connectivity, and 
other potential benefits. 
• The budget sheet needs to be routed to the appropriate departments and divisions for input 
before it is finalized. 
• There is an evaluation form for land acquisition that was used for CIP projects that may be 
used as a template (contact Carissa). 
• If hazard trees are an issue during land acquisition associated with development projects, 
require developer's arborist to conduct a hazard assessment for review and inspection by 
City Arborist. 
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APPENDIX D 
8. No policy for protecting deed restricted trees and significant habitat trees during building additions 
(Planning, Building) ; 
• This item should be further addressed during the Tree Code updates. 
• However, for deed restricted trees, the City can require a protection plan for building 
additions that complies with the original tree protection plan for the development project. 
• For trees in sensitive lands, the City can restrict access/building within the driplines of trees 
through the use of tree protection fencing. Section 18.790.060 prohibits damage to a 
protected tree or its root system. 
9. No policy of requiring exempt City projects to follow standards required by private development 
(Planning, Capital Construction and Transportation, Public Works) ; 
• City Arborist to attend "kickoff meetings" for City projects to identify applicable City rules 
and regulations. 
• Project plans will be routed to City Arborist for review and comment prior to completion. 
• Depending on the size of the project, the City Arborist may provide assistance on tree 
protection and planting specifications, or recommend that the City hire a project arborist. 
• Work with the Tree Board and Community Development Director on developing a set of 
standards for City projects to follow. 
10. No review of exempt City projects for trees by plannjng staff (Planning, Capital Construction and 
Transportation , Public Works) ; 
• City Arborist to attend "kickoff meetings" for City projects to identify applicable City rules 
and regulations. 
• Project plans will be routed to City Arborist for review and comment prior to completion. 
• Depending on the size of the project, the City Arborist may provide assistance on tree 
protection and planting specifications, or recommend the City hire a project arborist. 
11 . No formal hazard evaluation process for parks/greenspaces (Planning/Arborist, Public 
Works/Parks, Risk) ; 
• Budgeting has eliminated non-emergency management and evaluation of hazards in 
parks/greenspaces due to the transfer of the greens pace coordinator (urban forester) 
position from Public Works to the associate planner/arborist (city arborist) position to 
Community Development. 
• Proactive evaluation and management of City owned parks/green spaces would be best 
accomplished through the hiring of a greenspace coordinator to fill the position vacated in 
Public Works. 
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APPENDIX D 
• A greenspace coordinater could develop a program based off of protocols developed by the 
USDA Forest Service and/or International Society of Arboriculture. 
• Alternatively, the City could contract with a private arborist to develop a hazard evaluation 
and management program. 
12. No formal emergency response system for tree hazards on streets (Planning!Arborist, Public 
Works/Streets) ; 
• When a member of the public calls the City about a potential hazard tree on a City street, 
they should be forwarded to the Public Works front desk (503-639-41 71) . 
• Operators at Public Works will route the call to the Streets Division manager, who will in 
turn assign a staff member to investigate the complaint. 
• If the tree clearly is not a hazard, the Streets Division will contact the citizen and close the 
case. 
• If the tree is already down or is clearly an immediate hazard, the Streets Division will 
coordinate traffic control, contact other impacted agencies (such as PGE if power lines are 
involved) , and remove the tree from the street and sidewalk right-of-way using the City's 
contract arborist (or any other available private arborist if the contract arborist is not 
available) . The debris from the removal will be placed on the owner's property, and debris 
disposal will occur at the owner's expense. 
• If the tree hazard is a borderline case, the City Arborist will make a determination whether 
the tree should be retained, monitored, removed, or further investigated by the contract 
arborist. 
• If the City Arborist decides the tree is a hazard and there is enough time, he will write a 
letter to the responsible property owner giving them a specific period of time to abate the 
hazard. If the deadline is not met, the responsible owner will be cited through Code 
Enforcement. 
• If the hazard is after hours, citizens will need to call the Public Works after-hours number 
(503-639-1554). Public Works will then investigate the hazard after hours and either 
contact the contract arborist (or any other available private arborist if the contract arborist 
is not available) if there is an immediate hazard, or forward the inquiry to the Streets 
Division for follow up the following business day if the hazard is not immediate. The Streets 
Division will then follow the same process outlined above. 
13. No formal emergency response system for tree hazards in parks/greenspaces (Planning!Arborist, 
Public Works/Parks) ; 
• When a member of the public calls the City about a potential hazard tree on City property, 
they should be forwarded the Public Works front desk (503-639-4171) . 
• Operators at Public Works will route the call to the appropriate division manager, who will 
in turn assign a staff member to investigate the complaint. 
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• If the tree clearly is not a hazard, the responsible division will contact the citizen and close 
the case. 
• If the tree is determined to be an immediate hazard, the responsible division will contact 
the City's contract arborist (or any other available private arborist if the contract arborist is 
not available) to abate the hazard immediately. 
• If the tree hazard is a borderline case, the City Arborist will make a determination whether 
the tree should be retained, monitored, removed, or further investigated by the contract 
arborist. 
• The City Arborist is estimated to respond to one "borderline" call per week on average. If 
the time commitment is significantly more, the process may need to be reevaluated. 
• If the hazard is after hours, citizens will need to caU the Public Works after-hours number 
(503-639-1554). Public Works will then investigate the hazard after hours and either 
contact the contract arborist (or any other available private arborist if the contract arborist 
is not available) if there is an immediate hazard, or forward the inquiry to the appropriate 
division if the hazard is not immediate for foUow up the foUowing business day. The 
responsible division will then foUow the same process outlined above. 
14. Tree removal in sensitive lands requires tree removal permits, not sure if there is awareness of this 
Code provision (Planning, Capital Construction and Transportation, Public Works) ; 
• City Arborist to attend "kickoff meetings" for City projects to identify applicable City rules 
and regulations. 
• Tree removal permits and fees in Tigard Development Code Section 18.790.050 are 
applicable for any tree removal over six inches in diameter within sensitive lands (including 
City projects). 
• Publicize program through periodic Community Development/Public Works/Capital 
Construction and Transportation coordination meetings. 
• Ensure the sensitive lands GIS layer is available through Tigard Maps for aU 
divisions/departments. 
• Clarify with Community Development Director if invasive/exotic trees are exempt from tree 
removal permit requirements. 
15. No formal process for spending/tracking tree mitigation fund expenditures and planting 
(Pianning/Arborist, Public Works, IT/GIS, Finance); and 
• GPS actual locations of mitigation trees/areas. The spatial data can then be loaded into the 
City's GIS system for tracking. 
• Information on mitigation trees to include location (x/y coordinates), size (db h) , species, 
date planted, condition, cash assurance/bond release date, tree ID code, and any additional 
information necessary to conduct resource analyses in the future . 
• Link mitigation trees (via a GIS point layer) and mitigation areas (via a GIS polygon layer) 
with IFIS (accounting system) so that expenditures can be directly related to specific 
projects . 
....-~------------------------------
City of Tigard Urban l'orc, Lry Code· Rc,-i,iom I \ 'o lumc \ ' I 2911 
City of Tigard I Urban Forestry Master Plan Appendix 
16. No formal process for determining adjustments to street standards to preserve trees 
(18.81 0.030.A. 7) (Planning!Arborist, Engineering). 
APPENDIX D 
• The City's policy is to maintain the required curb to curb width standards in the Tigard 
Development Code in all cases, regardless of existing trees. 
• However, during the development review process, when a healthy and sustainable tree in 
the right of way is identified by the project arborist and/or City Arborist, Development 
Engineering will allow adjustments to planter strip and/or sidewalk standards on a case by 
case basis. 
• The City does not currently have the authority to require private developers to preserve trees 
if they choose not to. 
17. No formal street tree maintenance process for limb/root clearance and removal (Planning!Arborist, 
Public Works/Streets). 
• If the street tree is the responsibility of the City, the corresponding division will maintain the 
clearance requirements outlined in the Tigard Municipal Code. 
• If a citizen complaint is received, the Streets Division will investigate. 
• If there is an immediate hazard (e.g. blocked stop sign, hanging limb, etc.), the Streets 
Division will prune the tree immediately. 
• If there is not an immediate hazard, the Streets Division will contact the responsible party 
directly and explain the Code requirements, or gather the information and forward to Code 
Enforcement if the owner is nonresponsive. 
• If the potential branch clearance hazard is after hours, citizens will need to call the Public 
Works after-hours number (503-639-1554). Public Works will then investigate the hazard 
after hours and either contact the contract arborist (or any other available private arborist 
if the contract arborist is not available) if there is an immediate hazard, or forward the 
inquiry to the Streets Division if the hazard is not immediate for follow up the following 
business day. The Streets Division will then follow the same process outlined above. 
• When tree roots are impacting City streets or utilities, the responsible division will 
investigate and, if needed, contact the City Arborist for root pruning advice. 
• If the City Arborist decides the tree can be safely root pruned to make the necessary repairs, 
the responsible division will absorb the cost of root pruning. 
• If the tree cannot be safely root pruned and the tree needs to be removed, the City will 
absorb the cost of removal, but the property owner will be responsible for stump removal 
and replanting. Prior to removing a street tree, the City Arborist shall be contacted. 
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City o f Tigard Urban f-o restry Code ReY isions I Volume V I 291 
Urban Forestry Master Plan Appendix I City of Tigard 
APPENDIX E 
'tl 
2-10 
LAND USE P LANNING 
Section 2: Tigard's Urban Forest 
A defining community feature of Tigard is its trees and the urban forest they 
create. Unlike natural forests or managed timberland, Tigard's urban forest is a 
mosaic of native forest remnants and planted landscape elements interspersed 
with buildings, roads and other elements of the urban environment. The 
protection, management, and enhancement of this resource is important not 
only for Tigard's aesthetic identify and sense of place, but for the social, ecolog-
ical, and economic services it provides to the community. 
Trees and other types of vegetation are integral to the quality of Tigard's 
aesthetic, economic, and natural environments. Plants provide variation in color, 
texture, line and form that softens the hard geometry of the built environment. 
They also enhance the public and private realm through the provision of shade 
from the sun and wind, providing habitat for birds and wildlife, enhancing 
community attractiveness and investment, improving water quality and soil 
stability, and promoting human health and well-being. 
Tigard's trees and native plant communities have experienced significant disrup-
tion and displacement, first by agriculture and logging in the 19th century, and 
by increasingly dense urban development in the 20th Century. Competition from 
introduced invasive species such as English ivy, reed canary grass, and Himalayan 
blackberries has made it difficult for remaining native plant communities to 
thrive. However, remnant stands of native tree and associated plant commu-
nities still remain within the City Limits. Trees are important members and 
contributors to natural resource systems including upland habitat areas and plant 
communities, and functioning riparian corridors including the Tualatin River, 
Fanno Creek and its tributaries, and their adjacent flood plains and wetlands. 
In addition to remnants of the native forest, Tigard possesses a large number of 
City o f T igard Comptl'hl'n,; ivl' Plan 
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Ci tY of Tigard Urban Fores trr Code Rc,·isions I \ 'olumc \ ' I 292 
City of Tigard I Urban Forestry Master Plan Appendix 
LAND USE PLANNING 
mature and outstanding specimens of native and non-native trees planted when 
the area was rural country-side in the late 19th and early 20th centuries. Aerial 
photos demonstrate that increasingly more trees were planted on both public 
and private property during a period of large lot residential subdivision develop-
ment from the late 1940's through the 1970's, many of which survive to this day. 
Community attitude surveys reveal that Tigard Citizens place high value on the 
protection of trees and are concerned about the impact of development upon 
existing tree resources. Community surveys conducted in 2004 and 2006 show 
that residents value their neighborhood as a suburban retreat, a place that allows 
for views of trees and other natural areas. The 2006 Community Attitudes 
Survey found "the protection of trees and natural resource areas" as rating 
the highest of all "livability" characteristics posed to the respondents, scoring 
8.4 out of 10 points. Preservation of trees and other natural resources scored 
higher on resident's livability index than neighborhood traffic (8.2), maintaining 
existing lot sizes (7.8), pedestrian and bike paths (7.7), and compatibility between 
existing and new development (7.6). A follow-up question contained in the 
2007 survey revealed that 84% of Tigard Residents supported regulations to 
protect existing trees, with only 6% strongly disagreeing and 9% somewhat 
disagreeing. In addition, 90% of Tigard residents thought the City should take 
the lead in preserving open space. These values are also shared by residents of 
adjoining jurisdictions who maintain, or have begun significant updates to, their 
tree protection ordinances. 
The City of Tigard has been a Tree City, USA since 2001 because of aggres-
sive programs to plant trees on public property. In partnership with Clean 
Water Services, the City of Tigard is in the early stages of a series of stream 
restoration and enhancement projects intended to improve water quality, reduce 
erosion, and provide shade, structure and food sources to fish and other wildlife. 
Projects currently underway within the City's floodplains and riparian areas will 
result in the planting of approximately 100,000 native trees over a 10 year period 
(Fiscal Years 2001-2011). Through volunteer projects, cooperative efforts with 
non-profits, contract services, and the labor of Public Works crews, thousands 
of young trees are annually planted on public property. 
Not including restoration projects, the City's Public Works Department annually 
plants approximately 250 new or replacement trees on public lands, distributes 
approximately 50 street trees each year to private property owners through the 
Street Tree Program, and plants an addition 25 trees in celebration of arbor day. 
Comprehensive Plan City of Tigard 
APPENDIX E 
2-11 
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City of Tigard Urban Forestry Code Rc,·isions I Volume V I 293 
Urban Forestry Master Plan Appendix I City of Tigard 
APPENDIX E 
~ 
2-12 
LAND USE P LANNING 
Native species are given preference and are regularly planted along trails, riparian 
areas, and in new park and green space areas. T he o bjective is to increase the 
total number o f trees, particularly in areas where summer shade is desired such 
as picnic areas and next to sidewalks. Money is budgeted each year to maintain 
new trees being established and to remove hazard trees located on public 
property. As more public property is added and trees grow older, the number 
of hazard trees pruned or removed each year will continue to grow. T he level 
of new tree planting is limited by the maintenance capacity o f City work crews. 
Conditions and circumstances have significantly changed since the adoption of 
Tigard 's Comprehensive Plan in 1983. Rapid urban development has resulted 
in a general perception that the City has experienced a significant loss of tree 
canopy, and o ther vege tation essential for wildlife habitat, erosion control, 
slope stability, wa ter guality, air-guality, and community aesthetics. Driving 
this perception are METRO land use regulations, failed annexation efforts and 
changing market conditions resulting in higher density development than was 
anticipated in 1983, further challenging the City to pro tect trees and canopy 
cover while accommodating new development. Additionally, the City does no t 
currently have a comprehensive tree management and urban forest enhancement 
program to address these issues in a unified and consistent manner. As a result 
there is general feeling among residents, developers, and other stakeholders that 
the existing regulatory structure is no t adeguate and hinders bo th the strategic 
protec tion o f trees and the orderly urbanization o f the City. 
The City has historically relied upon its Development Code to manage and 
protec t trees on private property, particularly heritage trees and those located 
within steep slopes, wetlands, and o ther sensitive lands. Existing regulations 
reguire new development to protect and / or replace existing trees wherever 
possible, to pay into a mitigation fund when trees are removed, and to plant new 
street trees and landscape trees as part o f all new construction. In addition, 
trees within vegetated corridors surrounding wetlands, riparian corridors, and 
o ther natural bodies o f water are also pro tected by Clean Water Services as part 
o f their stormwater management program. These regulatory structures do no t 
recognize or pro tec t existing trees outside o f those areas, and o ffer little protec-
tion unless a development action is pending, or prior conditions o f develop-
ment approval designated the affected tree(s) for fu ture pro tec tion. As a result, 
the existing regulatory structure does not encompass a significant number of 
trees across the city, which may be removed by the property owner without City 
consultation or permit. Additionally, because the City does no t have a compre-
City of Tiga rd Compn: hcn ,;ivc Plan 
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City ofTiganl Urban l'o rc,; try Code Rc,·isions I \'olumc \ ' I 2\14 
City of Tigard I Urban Forestry Master Plan Appendix 
LAND USE PLANNING 
hensive tree removal consultation or permit system, protected trees (such as 
street trees) have been removed despite existing regulations or restrictions in 
force. 
KEY FINDINGS: 
• 
• 
• 
• 
• 
• 
• 
• 
A defining community feature is Tigard's urban forest, a mosaic of native 
forest remnants and planted landscape elements interspersed throughout the 
City. 
This urban forest provides social, economic, and ecological services that 
create public and private value to residents, businesses, and visitors. 
Mature and well-managed trees provide the maximum public benefits . 
The City continues to allocate staff and resources to tree planting, tree main-
tenance, and outreach activities. Additionally, new development is required 
to install street trees, landscape trees, and trees for mitigation purposes. 
The existing urban forest continues to experience significant disruption and 
displacement through the conversion of land to more intense urban land 
uses and competition from invasive species. 
Existing tree regulations are dispersed throughout the code; applied by 
multiple divisions in a non-unified and inconsistent manner; and sometin1es 
conflicting between different code sections. 
The City does not presently have a comprehensive and unified process to 
monitor tree removal and enforce existing tree protections outside of devel-
opment permit review. Furthermore, landowners are not always aware of 
regulatory protections applicable to their property or street trees adjacent to 
their property. 
Community attitude surveys reveal that Tigard residents place high value on 
the protection of trees witllin the community, that they are concerned about 
the impact of development upon existing tree resources, and are strongly in 
favor of a regulatory structure that would protect additional trees. 
GOAL: 
2.2 To enlarge, improve and sustain a diverse urban forest to maximize the 
economic, ecological, and social benefits of trees. 
POLICIES : 
1. The City shall maintain and periodically update policies, regulations 
and standards to inventory, manage, preserve, mitigate the loss of, and 
Comprehensive Plan City of Tigard 
City of Tigard Urban Forestry Code Rc,·isions I Volume V I 295 
APPENDIX E 
~ 
2-13 
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Urban Forestry Master Plan Appendix I City of Tigard 
APPENDIX E 
~ I • 
• 
2-14 
LAND UsE PLANNING 
enhance the community's tree and vegetation resources to promote their 
environmental, aesthetic and economic benefits. 
2. The City's various codes, regulations, standards and programs relating 
to landscaping, site development, mitigation, and tree management 
shall be consistent with, and supportive of, one ano ther; administration 
and enforcement shall be regulated and coordinated by the variously 
impacted departments. 
3. The City shall continue to regulate the removal o f trees, within environ-
mentally sensitive lands and on lands subject to natural hazards. 
4. T he City shall ensure that street design and land use standards provide 
ample room for the planting of trees and o ther vegetation, including the 
use of flexible and incentive based development standards. 
5. The City shall require the replacement and / or installation of new street 
trees, unless demonstrated infeasible, on all new roads or road enhance-
ment projects. Trees should be planted within planter strips, or at the 
back o f sidewalks if planter strips are not feasible or would prohibit the 
preservation of existing trees. 
6. The City shall establish and enforce regulations to protect the public 's 
investment in trees and vegetation located in parks, within right-of-ways, 
and on other public lands and easements. 
7. The City shall conduct an ongoing tree and urban fo rest enhancement 
program to improve the aesthetic experience, environmental quality, and 
economic value o f Tigard's streets and neighborhoods. 
8. The City shall continue to maintain and periodically update approved 
tree lists for specific applications and site conditions, such as street trees, 
parking lot trees, and trees for wetland and riparian areas. 
9. The City shall discourage the use or retention o f invasive trees and other 
plants through the development review process. 
10. The City shall require the appropriate use of trees and o ther vegeta tion 
as buffering and screening between incompatible uses. 
11 . The City shall develop and implement a citywide Urban Forestry 
C ity of Tiga rd Compreh cn~ ivc Plan 
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Cit:r ofTiganl Urban l'orc, try Code Rc,-i, iom I \ 'olume \ ' I 2% 
City of Tigard I Urban Forestry Master Plan Appendix 
LAND USE PLANNING 
Management Master Plan. 
RECOMMENDED ACTION MEASURES: 
1. Develop and implement a comprehensive, coordinated update and 
enhancement of all tree related regulations, standards, programs, and 
plans. 
u. Develop and implement an inspection and enforcement program 
that will ensure ongoing maintenance of trees and other vegeta-
tion required by development approval, with particular attention 
to challenges introduced by the change of ownership of affected 
properties. 
ill. Develop and implement an inspection and enforcement program 
that will ensure non-development related tree management and 
removal complies with the City's tree protection ordinances such as 
heritage trees, street trees, and trees on sensitive lands. 
tv. Inventory and evaluate street tree, parking lot and landscape area 
plantings that have failed to thrive, and determine if site conditions 
or management practices can be modified, and/ or if trees can be 
planted elsewhere in order to satisfy conditions of development 
approval or provide the benefits expected of the original planting. 
v. Develop and maintain, as part of the City's G IS and permit systems, 
a publicly accessible inventory of tree plantings, permitted removals, 
and the state of the City's urban forest. 
vt. Develop and distribute educational materials and programs regarding 
City policies, regulations, and good arboricultural practices for the 
general public, developers and city staff regarding tree planting, 
maintenance, and protection. Materials should be published in both 
paper and electronic media and in multiple languages. Particular 
focus should be given to new property owners who may be unfa-
miliar with the City's regulations and development related restrictions 
affecting their property. 
vii. Encourage and promote the removal of nuisance/invasive plants, 
Comprehensive Plan City of Tigard 
APPENDIX E 
~ 
2-15 
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City of Tigard Urban f'orest:ry Code Rc,·isions I Volume \' I 297 
Urban Forestry Master Plan Appendix I City of Tigard 
APPENDIX E 
'Fe 
2-16 
LAND USE PLANNING 
and the installation of trees and vegetation that are low maintenance, 
drought tolerant, site appropriate, and require minimal chemical 
applications. Strategies could include the production and distribu-
tion of approved tree li sts to area nurseries, landscaping companies, 
libraries and similar businesses and public resources. 
viii. Utilize approved tree and plant lists that emphasize long lived 
evergreens, broad-spreading deciduous varieties, and native species, 
but allow flexibili ty to choose a wide variety of species that are 
proven suitable for local climate conditions and for specific uses and 
locations. 
tx. E ncourage efforts by community groups and neighborhoods to 
plant trees and undertake other projects, such as restoration of 
wetlands and stream corridors. 
x. Maintain a list o f invasive plants, discourage the sale and propaga-
tion of these plant materials within the City, promote their removal, 
and prevent their reestablishment or expansion. 
GOAL : 
2.3 To balance the diverse and changing needs of the City through well-
designed urban development that minimizes the loss of existing trees to 
create a living legacy for future generations. 
POLICIES: 
1. The City shall develop and implement standards and procedures 
designed to minimize the reduction of existing tree cover, with priority 
given to native trees and non-native varietals that are long lived and / or 
provide a broad canopy spread. 
2. In prescribing the mitigation of the impacts of development, the City 
shall give priority to the protection of existing trees, taking into consid-
eration the related financial impact of mitigation. 
3. The City shall develop policies and procedures designed to protect 
trees, including root system s, selected for preservation during land 
C ity of Tiga rd C:omprchcn ,;ivc Plan 
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City of Tigard Urban l:orcslrl' Code Rc,·isions I \'olumc \ ' I 2'JH 
City of Tigard I Urban Forestry Master Plan Appendix 
LAND U SE P LANNING 
development. 
4. The City shall address public safety concerns by ensuring ways to 
prevent and resolve verified tree related hazards in a timely manner. 
5. The City shall develop and enforce site design and landscape require-
ments to reduce the aesthetic and environmental impacts of impervious 
surfaces through the use of trees and other vegetation. 
6. The City shall, in order to preserve existing trees and ensure new trees 
will thrive, allow and encourage flexibility in site design through all 
aspects of development review. 
7. The City shall require all development, including City projects, to prepare 
and implement a tree preservation and landscaping plan, with the chosen 
trees and other plant materials appropriate for site conditions. 
8. The City shall continue to cooperate with property owners, businesses, 
other jurisdictions, agencies, utilities, and non-governmental entities to 
manage and preserve street trees, wetlands, stream corridors, riparian 
areas, tree groves, specimen and heritage trees, and other vegetation. 
9. The City shall require, as appropriate, tree preservation strategies that 
prioritize the retention of trees in cohesive and viable stands and groves 
instead of isolated specimens. 
10. Applications for tree removal and tree management plans shall be 
reviewed by a certified arborist employed or under contract to the City. 
11. The City shall recognize the rights of individuals to manage their resi-
dential landscapes. 
RECOMMENDED ACTION MEASURES: 
1. Develop and implement regulations, standards, and incentives to 
encourage developers to transfer density, seek variances and adjust-
ments necessary to preserve trees and natural open space in a 
manner that op timizes tree preservation and protection. 
Comprchcn~ivc Plan City of Tigard 
APPENDIX E 
~ 
2-17 
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City of Tigard Urban Forestry Code ReYisions I Volume V J 299 
Urban Forestry Master Plan Appendix I City of Tigard 
APPENDIX E 
~ 
2-18 
LAND U SE P LANNING 
11. D evelop tree-mitigation regulations and standards to guide the City 
in assessing fees or compelling compensa tory action resulting from 
violation of its tree protection standards and / or conditions of devel-
opment approval. Consideration shall be given to off-site mitigation 
on both public and priva te lands, and the maintenance of a publicly 
accessible registry of mitiga tion sites both historical and po tential. 
111. Conduct surveys, workshops, and / or other public outreach strategies 
to identify and implement an appropriate strategy and form for tree 
protection regulations outside of the development review process. 
tv. E ncourage o ther jurisdictions operating within and adjacent to 
Tigard to prepare and implement a tree preservation and landscaping 
plan as part o f all development and infrastructure projects. 
v. Develop standards and procedures to identify and abate tree related 
hazards on bo th public and private property .. 
City of Tigard C:ompn:IH:n ,; ivc Plan 
....----------------------------------
City of Tiga rd Urban 1:orcsrry Code Rc,·isions I \ 'olumc \ ' I ."\!Ill 
5kotch of 
Kalapuya 
man drawn 
by Alfred 
Agate, a 
member of 
the Wilkes 
Expedition 
in 1841 . 
Urban Forestry HistoricalTimeline 
3500 years before present Ka lapuyo-(Nallve Amer1cans) began managmg 
the forests of the W1llamette Valley • 
us1ng tire (pyrocu~ure) .' I { n 1851 , canopy coverage 
In the early 1850s, Tigard was 
settled by several families of 
European descent including 'Hle 
Tigard family headed by Wilson 
M. Tigard. Native forests were 
cleared for agricuttural uses 
and timber help support 
development in the area.1 
w1tt11n the current City 
• hm1ts of Tigard was ~ 
I est1mated to be 52.4% ' (3,966.9 acres). 
' • In 1910, the Oregon Electric 
One Cloud Surveying Crew 1903- 1905 
Railway arrived, triggering 
more rapid development at 
the rail stop near Main Street. 
Fruit and nut packaging and 
canning plants and lumber 
mills set up shop at that point 
to capitalize on the agriculture 
and logging activity.' SUIV8y aew of Oregon Electric Co. RaiR.d ("'-' Ch.wles F. Ttgard) 
Downtown Toganl 
t..ft. to right Mrs. P.E. Lewis' Dry Goods Store. BoiHtS (later Schubring 
& Bied..-.nan's) Grocery Store, Krueger's Pool Hall and Barber Shop 
In the 1940s the populali}on I I ~ Aid<•rt'• Plumb;ng Shop•. 
was about 300 people ~~ ~mpaved street and no walcsways between buildings. Circa 1911 • 
..oil even after the arrival . \ 
"'1111 of the Capitol 
Highway (!19WJ.' L___Ggard was incorporated as a Crty in 1961 . There were 1,749 residents 
· ~~d 572 occupied residences at the time of incorporation.• 
HI The biggest boom period took place in the 1960s, averaging 26% H populationlgrowth.' In 1967, Tigard adopted rts first zoning ordinance. The only mention)o ~ trees in the zoning ordinance was in Section 1~7, which required trees i industrial developments to provide a buller lor streets and residential zones . 1'-tin 1972, the Municipal Code contained provisions to protect the public , from dangerous trees and branches blocking streets and sidewalks. 
• Planned developments were required "to the maximum extent 
In 1982, Tigard adopted<!!Hs possible ... , to oa~ure that natural features of the land are preserved" 
first ComprehensiveiPian with• I and IOJpro,VI_de_ a prehmmary tree plantmg plan (w1thl .. . all ex1stmg 
several policies that call fo(" trees ~over SIX 1nches m d1ameter and groves of trees. 
~ the preservation of stream 
areas, and wetllmds. • · the Comprehensive Plan. Tihe Tree Removal section of the new Code 
habitat, tree and timbef:ed 't In 1.983, the Community Development Code was revised to comply with 
corri~ors , fish and wildlife H 
'It ~quired a City)perrnit prior to tree removal lor all undeveloped land, 
develOped commercial and 1ndustr1alland, and pubhc land. 
In 1983, the Landscaping and Screening Chapter was also established~\ r:-- = ......___..,l_ 
and required street tree planting, protection, and replacernentlduringJ • ··· 
development. II also required trees to be usedJas a buffer'belween1 I 
differing land uses and lor shading of/parking lots. I~ 
In 1987, the Tigard Municipal Code•wa}s 't 
expanded to prohibit dead)or, hazar.dous • 
trees that pose a threat]to the pu61 iC\'and] 
private property ownersi(Sectihnl 7l4ill060). 1 
In 1997, the Tree Removal Chaptet'was sign~i ~ 
fK:antly1revised. Tree plans were required '1 ~ lor development~mijigatiOn •standards were;, · . , In 2001\ IIJe, Tig,a! d. Ti)lmgil!" 
established, and'tree removal perrnitslwerel l -~ Des•gn1Standards m the 
required lor trees in sensitive fandk!i · Community Development 
' Code esfublished]addliional 
· · · ·' F :;-,_____·· landscaping,andlscreening In 1998, the C1ty h~red rts lim Uroan, oreste::.._r-- _ requirements lor 'the Tigard 
;]---
Trianglel (the arealboundl by 
In 2001 , the Tree Board was established to develbp and administer' .-~ Highways 5r99, and 21il)). 
comprehensive,tree management program lor trees1on publ il: propet:ly I~ 
In 2002, the Tigard Municipal Code was revised to increase•protectionu.-• M]Jgard h,as been,named a1:r:ree City USA\by~ ~· ~ 
for trees on City property. e 1 the Nat•onai]ArtJO(IDay Foundation every >II'" . 
I year smce 200t. li-ln 2002, the Washington sq~are Region}a ' • Center Design Standards• and the Durham ~ l1IEE ern' l iSA Quarry Design ,,Standatds establ ished u~1 In 2002,otf1e Sensitive,Lands Cha~tertwas significantly revised in order 
. add1t1onal landscap1ng\and screen1ng ·~ to implement "Clean Water/Services (CWS)'Oesign and Construction 
requ~rements 1n the Washmgton.Square~n,d standards", thel"MetJ:o Uroan Growth Management Functional Plan," 
Bndge~ a: asJrespect1v.e!y. , I and •staiewide ~Ianning Goal S (Natural Resources)." 
In 2006, the Heri_lage T~ee program wau-· --U 
establ ished so/ that trees ol) l~ndmark • lnJ2007/the Tree Board'slmissi:OO was expanded to develop a "City Tree 
importance could]be offii:lallylrecognized • StewardShip and Utban Forest]Enbancement P~ogram" in part to ensure 
and protected. tree codei revisions1occurred i_o a cornprehensiv_e1manner. 
In 2007, the•Ci}y adopted a "Signilicanu-11n 2001iJ;an1Urban,Fllrest section was added to the. Comprehensive Plan 
Habitat Areas Map" which expanded the lands • , following over a'year,ol 'work by theiTree Board. Tihe Uroan For. est' section 
where tree removal perrnijs wete required. • . of the Comprehensivl! Plan!contains ~o goals to be implemenfed by 22 
I policies. Goall2.2 Pol1'cy 11 olfthe Comprehensive Plan states,"•fihe,Cijy -- . . . D-- shall develop and implement a citywide Uroan Forestry Management· 
In 2009, Tigard receiVed a Tr,eeJCJty USA growth • Master Rlan." Th is Plan is intended to meet th is policy requ&ement. 
award lor 1ls expanded)urban forestry efforts. IJ 
~ 
City of Tigard Urban Forestry Code Re,·isions I Volume V I 301 
)> 
"0 
"0 
m 
z 
0 
x 
'TI 
Urban Forestry Master Plan Appendix I City of Tigard 
APPENDIX G 
Federal/State/Regional Urban Forestry Policy Framework 
The City of Tigard is required to comply with various Federal , State, and Regional requirements when managing its 
urban forest. Urban forest management practices also have positive externalities that further progress towards other 
jurisdictional goals and mandates. The following represent major Federal , State, and Regional agencies and programs 
that influence or are benefitted by urban forest management in Tigard: 
Oregon Department of Forestry 
The Oregon Department of Forestry (ODF) is responsible for administering the Forest Practices Act (FPA) . The FPA was 
designed to promote the proper management of Oregon 's forests and ensure that forests remain healthy and productive. 
The Oregon Legislature has given cities the authoriW to regulate forests in place of having ODF administer the FPA as 
long as the local options meet the FPA's minimum standard. 1 
To meet the standards, local forest practice regulations must: 
• Protect soil, air, water, fish and wildlife resources; 
• Be acknowledged as in compliance with land use planning goals; 
• Be developed through a public process; 
• Be developed for the specific purpose of regulating forest practices; and 
• Be developed in coordination with the State Forestry Department and with notice to the Department of Land 
Conservation and Development.2 
Oregon Department of Transportation 
The Oregon Department of Transportation (ODOT) manages approximately 283 acres of ri ght-of-way in the CiW of 
Tigard including Hall Boulevard, and Highways 217, 5, and 99W. ODOT Bulletin RD06-03(B) provides specifications 
for street tree placement and maintenance in ODOT right-of-ways. These specifications are intended to balance the 
need for safeW along State roadways with trees, and supersede Tigard street tree requirements within CiW limits. 
Oregon Department of Land Conservation and Development 
The Oregon Department of Land Conservation and Development (DLCD) administers Oregon 's Statewide Land Use 
Planning Program and ensures that the comprehensive plans of Oregon cities comply with Oregon Statewide Land Use 
Planning Goals. 
'Oregon Department of Forestry and l.and Consen·ation and De,·clopment. I 999. Guidelines for D eveloping U rban Forest Practice 
Ordinances. State of Oregon, Department of Forestry and Department of l.and Consen·a tion and Dc,-clopmcnt. I 6p. 
2 Oregon Department of l'orestry. 2008. Forest Facts: U rban Growth Boundaries and the Oregon Forest Practices Act . . \ccessed Yia the 
World Wiele Web: < http: / / www.oregon.gm-/O DI '/I' UFlS/ docs/ l'orcst_l'acts/ Forest_Facts_Urban_Crowth_Boundarics.pdf> on !\ larch 25, 2009. 
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City of Tigard Urban Forestry Code Rc,·isions I \ 'olume \ ' I .)02 
City of Tigard I Urban Forestry Master Plan Appendix 
APPENDIX G 
The City of Tigard Comprehensive Plan is required to be consistent with 12 of the 19 Oregon Statewide Land Use 
Planning Goals. 
The following statewide planning goals directly relate to the urban forestry in Tigard: 
Goal 5. ''To protect natural resources and conserve scenic and historic areas and open spaces." 
This goal requires local governments to develop programs to protect resources including fish and wildlife habitats, 
stream corridors, and natural areas. Urban forestry programs and policies can further progress towards achievement of 
Goal 5. Economic, social, environmental, and energy (ESEE) analyses are required to protect Goal 5 resources. 
Goal 6. ''To maintain and improve the quality of the air, water and land resources of the state." It 
is well documented that urban trees and forests contribute to air and water quality improvement. 
Goal 7. "To protect life and property from natural disasters and hazards." Trees roots, canopies, and 
leaf litter in natural hazard areas help to prevent erosion and flooding (Portland Urban Forest Management Plan). 
GoallO. "To provide for the housing needs of citizens ofthe state." This goal requires the City to balance 
the needs of tree and forest preservation with the need for housing and efficient use of urban land. 
Local jurisdictions within the Metro regional planning boundary must also be consistent and coordinated with relevant 
Metro requirements such as the Urban Growth Management Functional Plan which is described in more detail below. 
DLCD has approved or "acknowledged" the City's Comprehensive Plan (including the Urban Forest section) as being in 
compliance with statewide planning goals, and consistent with Metro requirements. 1 
Oregon Division of State Lands 
The Oregon Division of State Lands (DSL) establishes criteria and procedures for the identification of wetlands. In 
1997, Tigard's Local Wetland Inventory was approved by DSL. Approval by DSL means that the inventory meets State 
standards, and therefore becomes part of the State Wetlands Inventory and must be used in lieu of the National Wetlands 
Inventory. 2 
Development in these areas is regulated by a variety of federal , state, regional, and local laws. Tigard Development 
Code Chapter 18.775 (Sensitive Lands) contains specific provisions to protect wetlands from development and requires 
1 Oregon Department o f Forestry and Land Consen ·ation and D eYelopment. 1999. Guidelines for Developing Urban Forest Practice 
Ordinances. State of Oregon, Department of Forestry and Department o f Land Consen ·ation and De,·clopment. 16p. 
2 Ci ty of Tigard. 2009. Comprehensive Plan (as of April22, 2009). City of Tigard, OR, Communi ty DcYclopment Department, Long Range 
Planning DiYision. 23Up. 
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APPENDIX G 
concurrent approvals from the U.S. Army Corps of Engineers, Oregon Division of State Lands, and Clean Water Services. 
As a result, trees and native vegetation in Local Wetlands gain a highly protected status. 
Oregon Department of Environmental Quality 
The Oregon Department of Environmental Quality (DEQ) is responsible for protecting Oregon 's air quality by issuing 
permits, developing programs, and monitoring air pollution to ensure communities meet the National Ambient Air 
Quality Standards (NMQS), and to protect Oregon's pristine views. Air pollutants identified in the 2005 DEQ Air Quality 
Report as the greatest concern in Oregon are: Ground-level ozone, commonly known as smog; Fine particulate matter; 
Hazardous air pollutants; and Carbon monoxide.1 
Regional efforts have been established to monitor and plan for pollutants. The City of Tigard is part of the Portland 
Area Airshed (PM) , which is defined by the Metro service boundary. The DEQ is responsible for ensuring the PM meets 
the national standards, and for developing the necessa1y plans to continue compliance. Currently, the PM meets all 
NMQS standards. However, DEQ is required to develop maintenance plans for carbon monoxide and ozone to ensure 
continued compliance. 1 
Trees have a natural ability to convert and sequester compounds that contribute to air pollution. Trees also offset power 
plant emissions by shading and sheltering buildings from sun and wind. 2 At the local level, the City can protect existing 
natural areas and mature trees, and promote and participate in tree planting effmts to improve air quality and decrease 
building energy usage. Within urban areas, air quality is often much worse along major roadways. Trees strategically 
planted along or near roadways have an increased ability to filter air pollutants and improve air quality before exhaust 
is released in the atmosphere. 1 
DEQ is also charged with establishing standards, regulating, and monitoring Oregon 's waters for compliance with the 
Federal Clean Water Act (CWA) and National Pollutant Discharge Elimination System (NPDES) . Within Tigard, run-off 
from impervious surfaces, pet waste, and erosion! sedimentation are the most problematic sources of water pollution. 
Planting and maintaining tree canopy, water quality facility construction and maintenance (vegetated swales and 
retention basins) , and stream corridor and wetland enhancements are all urban forestry activities that help to improve 
water quality and meet State and Federal requirements.1 
Oregon Public Utility Commission 
The Oregon Public Utility Commission (PUC) regulates utility industries to ensure that customers receive safe and 
reliable services at reasonable rates. In order to ensure safety, the PUC requires Portland General Electric to maintain 
1 City of Tigard. 2009. Comprehensive Plan (as of April 22, 2009). City of Tigard . O R. Community 1)~,-elopmcnt Department, l .ong Range 
Planning Di,-i,ion. 230p. 
2 i\ lc l'hcr>on, 1·:. <; ., S.l·:. i\ laco. J R. Simp>on. I'J Peper.<~- Xiao, .\. \ 'anDcr/.andcn, and N. Bell. 2002. Western Washington and Oregon 
Community Tree Guide: Benefits, Costs, and Strategic Planting. In ternational Society of Arboriculture, Pacific Northwest Chapter, Silverton, OR . 
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APPENDIX G 
zones surrounding overhead uti li ty lines clear of trees for safety and in order to help prevent outages. The result is 
increased maintenance costs and trees that become eyesores as a result of heavy pruning. Portland General Electric 
spends approximately $500,000 annually pruning trees away from the utility lines. 1 These costs are passed on to utili ty 
ratepayers. The urban forestry program can help to decrease maintenance costs and improve the aesthetic quality of 
local trees by aiding in the selection of appropriate trees near overhead lines.2 
Metro 
Metro helps the region 's cities implement Statewide Planning Goals through the Urban Growth Management Functional 
Plan (functional plan). Metro cities are required to adopt comprehensive plans and implementing regulations that 
correspond with the titles and policies in the functional plan. The functional plan contains 13 titles, some of which 
directly or indirectly impact urban forest management in Tigard. DLCD has acknowledged Tigard's Comprehensive 
Plan as being in compliance with statewide planning goals, and consistent with Metro's functional plan.3 The following 
excerpts from the functional plan have significant impact on urban forestry in Tigard: 
Title 1 of the functional plan is intended to meet Statewide Planning Goal 10, and focuses on increasing housing 
capacity in order to use land within Urban Growth Boundaries (an invisible line that separates rural areas from 
suburban) efficiently. To meet Title 1, each jurisdiction was required to determine its housing capacity and adopt 
minimum density requirements. Tigard adopted an 80% of minimum density requirement for development in 1998, 
which means that a development must build 80% of the maximum units allowed by the zoning designation.4 The 
Home Builder's Association of Metropolitan Portland (HBAMP) and others have cited this requirement as a significant 
impediment to preserving trees in urban areas, particularly for those properties that are zoned for high density. 
Title 3 protects the region's health and public safety by reducing flood and landslide hazards, controlling soil erosion 
and reducing pollution of the region 's waterways. Title 3 implements Statewide Planning Goals 5, 6 and 7 by protecting 
streams, rivers, wetlands and floodplains by avoiding, limiting or mitigating development impacts on these areas. The 
areas subject to these requirements have been mapped and adopted by the Metro Council, specifically, the FEMA 100-
year floodplain and the area of inundation for the February 1996 flood. Title 3 also protects rivers and streams with 
buffers that are typically 50 feet wide, requires erosion and sediment control, planting of native vegetation on stream 
banks when new development occurs, and prohibits the storage of new uses of uncontained hazardous material in water 
quality areas. Title 3 results in significant protection and enhancement of that portion of the urban forest in streams 
and floodways. Finally, Title 3 establishes perlormance standards to protect regionally significant fish and wildlife 
habitat areas to implement Statewide Goal 5.3 
1 Burns, C. 2008. Personal communication on October 6. Wes tern Forester, Portland General 1\lectric Company. Portland, OR. 
' Oregon Public Utili ty C:ommi" ion. 2009. Oregon Public U tili ty Commission Homepage. Accessed ,·ia the World Wide Web: < http://www. 
puc.s tate.or.us/> on 1\•larch 26, 2(Xl9. 
3 1\1etro. 2009. U rban Growth Management Functional Plan. r\ccessed Yia the World Wide Web: <http://www.oregonmctro.gO\·/Iiles/about/ 
chap307.pdf> on March 31, 2009. 
'City o f Tigard. 2(Xl9. Comprehensive Plan (as of April22, 2009) . City of Tigard, OR, Community De,·elopment Department, Long Range 
Planning Di,·ision. 230p. 
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Title 12 of the functional plan protects residential neighborhoods by prohibiting cities from increasing density in 
certain areas and requiring easy access to parks and greenspaces for City residents.• 
Title 13 is intended to " (1 ) conserve, protect, and restore a continuous ecologically viable streamside corridor system, 
from the streams' headwaters to their confluence with other streams and rivers, and with their floodplains in a manner 
that is integrated with upland wildlife habitat and with the surrounding urban landscape; and (2) to control and 
prevent water pollution for the protection of the public health and safety, and to maintain and improve water quality 
throughout the region." 1 
One of the results of Title 13 was the creation in the City of Tigard of 588 acres of habitat designated as "highest" 
value (i.e. Metro inventoried Class I and II riparian resources with in the Clean Water Services Vegetated Corridor) . An 
estimated 370 acres of Class I and II riparian habitat situated outside the Clean Water Services' vegetated corridor are 
designated as "moderate" value. In addition , 422 acres of non-Class I and II riparian resources within the City are 
designated as "lowest" value, including both upland forests and lower-value riparian habitat areas. The highest and 
moderate value habitat are curr~ntly protected through other regulatory processes and agencies such as CWS. The 
lowest value habitat consists of primarily upland forests and is currently vu lnerable to development. Additional ESEE 
analyses would be required to protect lower value habitat and additional Statewide Planning Goal 5 resources in the 
future.2 At the time of the writing of this document, the City of Tigard has proposed budgeting funds in FY2009-10 to 
protect additional upland tree resources. 
Clean Water Services 
The City collaborates with Clean Water Services ( CWS) , the surface water management and sanitary sewer system utility 
for urban Washington County, to protect local water resources. Through CWS Design and Construction Standards, local 
governments in the Tualatin Basin (including Tigard) developed a unified program to address water quality and flood 
management requirements for Title 3 of Metro 's Urban Growth Management Functional Plan.Z 
In 2002, the City of Tigard adopted regulations restricting development within, and adjacent to, sensitive water resource 
areas, including streams, through standards in the CWS Design and Construction Standards. The CWS standards provide 
for vegetated corridor buffers, ranging from 15 to 200 feet wide, and mandate restoration of corridors in marginal or 
degraded condition. Native trees over 6 inches in diameter in vegetated corridors are protected, and their removal 
requires replacement on a tree for tree basis. In addition , land-use applicants proposing development near streams 
and wetlands are required to prepare a site assessment and obtain approval from CWS prior to submitting a land use 
application to the City.2 
1 i\lctro. 2009. Urban Growth Management Functional Plan . 1\ ccessed via the World Wide Web: < http: / /www.oregonmetro.gov/ liles/about/ 
chap307.pdf> on i\ larch .11, 2009. 
'City of Tigard. 2009. Comprehensive Plan (as of April22, 2009) . City of Tigard, OR, Community De,-clopmcnt Department, l .ong Range 
l'bnning Di,·ision. 2.)0p. 7 Oregon Public Utility Commission. 2009. Oregon Public Utility Commission Homepage . . \ccessed ,·ia the World 
Wide Web: <http:/ / \\'\\'\\'.puc.state.or.us /> on !\ larch 26, 2009 . 
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APPENDIX G 
The City of Tigard also collaborates in implementing CWS' Healthy Streams Plan Qune 2005). The goal of this plan 
is to improve watershed and stream health for community benefit by recommending a number of policy and program 
refinements, as well as outlining a capital projects program. The capital projects focus on stream preservation and 
enhancement, flow restoration, community tree planting, stormwater outfall and culvert replacement. Tigard's Public 
Works Department is instrumental is achieving the goals of the Healthy Streams Plan through its Surface Water Quality 
program. 1 Many of goals of the Healthy Streams Plans are met through proper urban forest management activities 
such as invasive species control and streamside tree canopy restoration. 
Large municipalities typically have NPDES permits for their wastewater treatment facilities and for stormwater runoff, 
called a Municipal Separate Storm Sewer System (MS4) permit. In urban Washington County, which includes the 
City of Tigard, the permits have been combined and are held by CWS. The combined permit was issued for the entire 
TUalatin River watershed to guide a basin-wide effort to improve water quality. It requires CWS to submit a Stormwater 
Management Plan and a Wastewater Management Plan to DEQ. These two plans outline the best management practices 
that CWS, its member cities, and Washington County commit to employ to reduce pollutant discharges, regulate 
temperature, and comply with any Total Maximum Daily Load (TMDL) levels that have been established.1 Trees and 
urban forests are excellent stormwater managers and contribute to the achievement of water quality goals, yet are not 
typically addressed in Stormwater Management Plans. 
Constitutional Takings Issue 
In response to the question of whether a tree preservation ordinance constitutes a regulatory taking, the City Attorney 
has provided the following response: 
Oregon courts recognize that regulation of real property can go too far and become tantamount to a government 
appropriation of property. A regulation which goes too far results in a regulatory taking or inverse condemnation, in 
violation of Article I, section 18 of the Oregon Constitution. See Coast Range Conifers, LLC v. State, 339 Or 136, 117 
P3d 990 (2005) ; Boise Cascade C01p. v. Board of Forestry, 325 Or 185, 935 P2d 411 0996) ; Dodd v. Hood River 
County, 317 Or 172, 855 P2d 608 (1993) . 
The approach of courts under the Oregon Constitution "has been to ask whether the regulation leaves the owner with 
any economically viable use of the property." Coast Range Conifers. "Additionally, the court has recognized that 
regulations that deny an owner the ability to put his or her property to any economically viable use will result in a 
taking and entitle the owner to compensation." !d; see also Dodd (phrasing test as whether property retains "some 
substantial value"). 
1 City of Tigard. 2009. Comprehensive Plan (as of April 22, 2009). City of Tigard, OR, Communi ty De,·clopmem Department, I.ong Range 
Planning Di,-ision. 230p. 
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APPENDIX G 
Whether there remains any economically viable use of property is based on the effect of the regulation as specific to the 
characteristics of any property at issue. Therefore, it is imperative that when utilizing the Urban Forest Master Plan as a 
tool to guide the drafting of regulations, that the City Attorney be consulted regarding the constitutionality of the specific 
regulations in light of any new jurisprudence on the topic . 
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APPENDIX H 
City of Tigard Urban Forestry Policy Framework 
The City of Tigard has various policies and laws that frame and implement the urban forestry program. 
Comprehensive Plan 
The City of Tigard Comprehensive Plan acts as the City's "land use constitution." It is the document that provides 
the broad policy basis for Tigard's land use planning program and ultimately guides all actions relating to the use 
of land in the City. The Plan also signals that the City's land use planning efforts will implement state and regional 
requirements, including Oregon's land use planning goals and related laws, state administrative rules, and applicable 
Metro plans and requirements. The Comprehensive Plan contains goals, policies and recommended action measures 
that identify the intent of the City to accomplish certain results. The Urban Forest Section of the Comprehensive 
Plan contains two (2) goals, 22 policies, and 11 action measures specific to urban forestry in Tigard. The goals and 
policies are obligations the City wishes to assume. The City must follow relevant goals and policy statements when 
developing other plans or ordinances which affect land use. Therefore, the Urban Forestry Master Plan and future 
revisions to the tree ordinance must be consistent with Comprehensive Plan goals and policies. Recommended action 
measures support the obligations to achieve a desired end, but do not signify an obligation themselves. The discretion 
to what degree Plan policies are implemented belongs primarily to the City Council. 
Zoning Map 
The Zoning Map implements the Comprehensive Plan and guides development throughout the City. Zoning 
determines the type and intensity of development, as well as applicable Code provisions such as density requirements. 
As a result, zoning can impact the extent and feasibility of tree preservation for a given site. 
Code Provisions 
The Tigard Municipal Code and Development Code contain specific provisions that regulate trees and urban forestry 
in Tigard. The following is a list of the major tree and urban forestry related Code provisions, as well as commentary 
on those provisions that present administrative challenges. 
Chapter 7.40 (Nuisances) requires property owners to maintain minimum branch clearances of eight (8) feet 
over sidewalks and ten (10) feet over streets (section 7.40.060.A). It also prohibits owners from retaining dead 
or hazardous trees that threaten public or private property (section 7.40.060.B) . However, there is no procedure 
established for abating hazards on private property such as trees that are in imminent danger of falling. 
Section 7.40.050 (Noxious Vegetation) requires property owners to maintain vegetation and weeds so that they do not 
become unsightly or a hazard. However, it is unclear if invasive species control is required by this Code provision. 
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APPENDIX H 
Section 7.40.090 (Greenway Maintenance) establishes standards for greenway maintenance and prohibits the removal 
of non-hazardous trees over five (5) feet in height in greenways. However, the term "greenway" is not well defined. 
Chapter 9.06 (Trees on City Propetty) regulates the planting, maintenance, and removal of trees on City property 
including parks and public right-of-ways. It also authorizes Council to adopt by resolution a Tree Manual that 
provides detailed tree related standards and the City to create an approved Street Tree List. The Chapter defines a "tree" 
as a standing woody plant with a trunk diameter of two (2) inches at 4.5 feet above ground level. Chapter 18.790 
(Tree Removal) defines a "tree" at six (6) inches in diameter at four ( 4) feet above ground level. 
Section 9.06.030 (Tree Planting) requires written permission from the City prior to planting street trees or trees 
on public property. Section 9.06.050 (Tree Protection) requires development projects on City property to protect 
trees according to the specifications in the Tree Manual. Section 9.06.060 (Removal of Hazardous Trees from City 
Property) obligates the City to inspect reports of hazardous trees on City property and prioritize their removal based on 
the level of hazard. 
Section 9.06.070 (Removal of Trees from City Property) requires written permission for tree removal from City 
property and right-of-way, and requires mitigation per the requirements in the Tree Manual. 
The Tree Manual, which was adopted in 2002, provides detailed specifications for Chapter 9.06. However, 
administering the provisions in the Tree Manual are challenging because there are some conflicts with Code 
provisions elsewhere in the City Code. For example, street tree planting specifications in section 030 of the Tree 
Manual are different than the street tree planting specifications in Chapter 18.745 (Landscaping and Screening) . 
Also, the branch clearance requirements for sidewalks and streets in the Tree Manual are different than those in 
Chapters 7.40 and 18.745. Finally, referencing the Tree Manual is a challenge because the index at the beginning of 
the Manual does not correspond with the sections in the body. 
A tree plan and mitigation is required by sections 070 and 090 of the Tree Manual , but there it is unclear what triggers 
the tree plan requirement and what the scope of the tree plan should be. 
Chapter 9.08 of the Municipal Code contains the requirements for the City's Heritage Tree Program. The Chapter 
recognizes and protects trees or stands of trees on public or private property that are designated to be of landmark 
importance due to age, size, species, horticultural quality or historical importance. Participation in the program is 
voluntary and administered by the Tree Board, City Counci l, and staff. 
Title 18 (Community Development Code) defines a tree as a standing woody plant with a trunk that is two (2) inches 
in diameter at four ( 4) feet above the ground. This definition is inconsistent with the definitions of tree in Chapter 
9.06 and 18.790 of the Code . 
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APPENDIX H 
Chapter 18.330 (Conditional Use) authorizes the hearings officer to require conditional use developments to improve 
landscaping and increase tree and habitat preservation as a condition of development approval. 
Chapter 18.350 (Planned Developments) states as one of its purposes "to preserve to the greatest extent possible 
the existing landscape features and amenities (trees, water resources, ravines, etc.) through the use of a planning 
procedure (site design and analysis, presentation of alternatives, conceptual review, then detailed review) that can 
relate the type and design of a development to a particular site". Specific provisions in the Chapter require plans 
that identify areas of significant natural resources and methods for their maximized protection, preservation, and/or 
management. Planned Developments are approved by a 1\'pe III process by the Planning Commission. Therefore, 
Planning Commissioners have discretionary authority to require that sites are developed in a manner that trees 
and other natural features are incorporated into the project design . However, the Home Builders' Association of 
Metropolitan Portland (HBAMP) and others have commented that the Planned Development provisions are in need of 
revision because they are not conducive to infill development. 
The approval criteria in Site Developement Review section 18.360.090, includes many provisions requiring the 
preservation of trees and natural areas. For example, approval criteria A.2.a requires buildings to be " ... located to 
preserve existing trees ... where possible based upon existing site conditions". The approval criteria also requires trees 
to be preserved to the extent possible (A2.b) and the use of innovative methods to preserve fish and wildlife habitat 
located on the "Significant Habitat Areas Map". Site Development Review applications are reviewed and approved 
by staff through a Type II process which limits the amount of staff discretion. Therefore, the non-specific approval 
criteria above does not provide the tools needed to implement tree and habitat preservation. 
Chapter 18.370 (Variances and Adjustments) allows for Type I adjustments to use existing trees as street trees or to 
vary from the street tree requirements in Chapter 18.745 (Landscaping and Screening) if there are space constraints. 
Section 18.385.040 (Sensitive Land Permits) requires development within the 100-year floodplain, steep slopes, 
drainageways, and wetlands to obtain permits to preserve the safety and functionality of these areas. Tree Removal 
permits are required for the removal of trees in sensitive lands by section 18.790.050 of the Code. However, there is no tree 
protection plan requirement (section 18.790.030) for development within sensitive lands. 
Chapters 18.510, 18.520, and 18.530 describe the development standards for residential, commercial (including 
mixed use) , and industrial zones respectively. Among the provisions are minimum landscaping requirements, 
minimum and maximum density requirements, minimum building setback requirements, and minimum lot sizes 
and dimensions. These standards may have the greatest impact on the extent of tree and forest retention during 
development. 
Chapters 18.620 (Tigard Triangle Design Standards) , 18.630 (Washington Square Regional Center Design Standards) 
and 18.640 (Durham Quarry Design Standards) increase the caliper size of all required landscape and street trees 
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APPENDIX H 
in those planning areas. Some of the planting provisions in these special planning areas conflict which make 
interpretation difficult. For example, the landscaping and screening provisions in section 18.620.070, require tree 
spacing at a maximum of 28 feet on center. However, the provisions on page 18 of the Tri angle Design Standards 
specify one parking lot tree for every seven parking spaces (this creates spacing of more than 28 feet on center) . In 
addition the definition of tree types on page 18 are overly specific and therefore difficult to apply. 
Chapter 18.745 (Landscaping and Screening) specifies street tree, parking lot tree, buffer tree, and other landscaping 
requirements. The Chapter specifies that it is applicable to all development, but it does not detail what types of 
permits trigger the standards. The landscaping provisions are administratively applied to those developments that 
require a tree plan (section 18.790.030). The General Provisions (Chapter 18.745.030) require trees and landscaping 
to be appropriately planted, pruned, maintained, and protected during development. However, there is a lack of 
specificity in these requirements that make it challenging to ensure that trees and landscaping are properly installed, 
protected, and maintained. Section 18.745.040 (Street Trees) specifies the location and spacing of variously sized 
street trees. However, these specifications differ from those in section 030 of the Tree Manual. Also, there is no 
minimum spacing requirement for street trees and the branch clearance requirements for sidewalks and streets in 
Chapter 18.745.040 are different than those in Chapter 7.40 and in the Tree Manual. Section 18.745.050 (Buffering 
and Screening) requires trees and landscaping to be used as a buffer between differing land uses, aesthetics, and to 
provide shading for parking lots. The parking lot tree requirements (18.745.050.E) have not resulted in successfu l 
shading of parking lots. This is likely due to the limited soil volumes the provisions allow (minimum parking island 
dimensions are three feet by three feet) and the lack of specificity on installation requirements (e.g. irrigation is not 
specified for parking lot trees). 
The Sensitive Lands Chapter 18.775 protects sensitive lands for safety, functionality, and fish and wildlife habitat. 
It also implements "Clean Water Services (CWS) Design and Construction Standards", the "Metro Urban Growth 
Management Functional Plan", "Statewide Planning Goal 5 (Natural Resources) " and meets the National Flood 
Insurance Program requirements. The chapter requires a CWS Stormwater Connection permi t when tree removal 
occurs in sensitive lands (section 18.775.020.A.9) . Lawns and gardens are permitted in sensitive lands except in "CWS 
Water Quali ty Sensitive Areas or Vegetated Corridors" and "the Statewide Goal 5 vegetated corridor established for the 
TUalatin River" (18.775.020.8.1) . Exemptions from the provisions of the sensitive lands chapter are emergency repair, 
stream restoration projects, non-native vegetation removal, and routine maintenance as long as they comply with City 
Standards and Specifications for Riparian Area Management (section 18.775.020.C). Section 18.775.020.D requires 
development to obtain permits from regulating jurisdictions such as the Army Corps of Engineers or CWS prior to 
development in jurisdictional wetlands. Section 18.775.070 specifies the approval criteria for sensitive lands permits. 
Section 18.775.100 allows for adjustments to dimensional standards such as setbacks, building heights, or lot areas to 
preserve habitat and vegetation cover such as trees. Section 18.775.110 allows for density transfers in order to better 
protect vegetated corridors. While tree removal permits are required for sensitive lands areas by section 18.790.050, 
and habitat protection is a stated purpose for the sensitive lands chapter, there are no implementing provisions in 
either Code Chapter that explicitly require the protection of trees and forests in sensitive lands. 
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APPENDIX H 
Chapter 18.790 (Tree Removal) is what most people think of as the "Tree Code". This portion of the code regulates 
tree removal and replacement during certain types of development projects, requires tree removal permits for trees in 
sensitive lands, and prescribes the penalties for illegal tree removal. It also prohibits commercial forestry within the 
City limits. Section 18.790.020 provides definitions for some of the words used in the Chapter. Many have commented 
that some of the definitions need revision or clarification. For example, a "tree" is defined as a woody plant with a 
diameter of six inches when measured four feet above the ground. This definition is inconsistent with the definition 
of tree in the Municipal Code and does not account for trees that are less than six inches such as required mitigation 
trees. Also, the definition of "hazardous tree" is non-specific and could potentially include trees that are not intended 
to be defined as hazardous such as those in a forested area with little potential of striking people or other high value 
targets. Finally, the definition of commercial forestry is specific to the removal of 10 or more trees for sale per acre, 
per year. The definition is unclear whether the acreage should measured for the entire property, or for the stand of 
trees where the removal is occurring. 
Section 18.790.030 (Tree Plan Requirement) requires a tree protection, removal, and replacement plan for 
Subdivision, Partition, Site Development Review, Planned Development, and Conditional Use projects. Missing from 
the list are Sensitive Lands projects, building additions, demolitions, and other development projects with significant 
potential to result in tree damage or removal. 
Tree plans require mitigation for tree removal on an "inch for inch" basis. Therefore, developers are required to 
replant the number of diameter inches of existing trees removed from a development site with an equivalent amount 
of diameter inches of replacement trees. For example, if a 24 inch tree is removed from a development site, the City 
may require replacement with up to 12, two inch diameter trees. 
Also, as the percentage of trees removed from a site is increased, the percentage of replacement trees required for 
mitigation is increased. This has resulted in the overplanting of development sites to meet mitigation requirements as 
well as the preservation of inappropriate trees in order to avoid mitigation requirements. 
If developers are unable or unwilling to plant replacement trees, there is a fee in lieu of planting option (18.790.060. 
E) to cover the City's cost of replanting. This fee is currently assessed as $125 per diameter inch removed, and viewed 
as excessive by many of those in the development community. Also, the methodology used to create the fee in lieu is not 
well defined and has resulted in many questions as to the legitimacy of the $125 per inch figure. 
The tree protection requirements of the tree plan are not defined, and are left to the discretion of the project arborist. 
This has resulted in wide inconsistencies between protection methods for development projects, and limits the City's 
ability to require increased levels of tree protection. 
Trees removed within a period of one year before a development application are required to be inventoried and 
mitigated as part of the tree plan. This provision has created a loophole that some developers have exploited by 
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APPENDIX H 
removing trees from a site, waiting one year, and then submitting a development application in order to avoid tree 
mitigation requirements. 
Section 18.790.040 (Incentives for Tree Retention) provides developers incentives and flexibility options in order to 
preserve trees. However, the incentives are seldom utili zed, and often criticized for their impracticali ty. Many in the 
development community have called for an overhaul of the incentives so that they are more appealing and practical for 
developers. 
Section 18.790.040.8 requires preserved trees to be protected after development through a deed restriction. This 
requirement is difficult for City staff to administer as development plans are archived and difficult to quickly and easily 
assess in responses to inquires that occur years and decades after development. 
Section 18.790.050 (Permit Applicabili ty) requires tree removal permits for trees in sensitive lands areas. However, the 
approval criteria relate strictly to erosion control and not the other benefits provided by trees. Therefore, if an appropriate 
erosion control plan is provided by the applicant, any or all trees may be removed from sensitive lands areas. While 
hazardous trees are exempt from permit requirements, there is not a clear definition of what constitutes a hazardous tree 
and who is qualified to deem a tree hazardous. 
Section 18.790.060 (Illegal Tree Removal) outlines the penalties for illegal tree removal and specifics the tree replacement 
requirements for violations and mitigation. The tree replacement requirements in 18.790.060.0 are vague and difficult 
to administer. The most challenging aspect is the lack of spacing requi rements, which further contributes to overplanting 
and lack of adequate spacing for mitigation trees. There is also little specificity on species requirements, which tend to 
lead to the planting of small stature and narrow crowned trees so that more trees can be planted to meet the "inch for 
inch" replanting requirements. Finally, the fines for illegal tree removal include the appraised value of the tree illegally 
removed. This can be challenging when there is not clear documentation of the previous condition of the tree. One 
solution may be to set a minimum penalty for cases where there is no evidence of the species or condition of the illegally 
removed tree. 
Section 18.810 (Street and Utility Improvement Standards) specifies the minimum planting strip width for street trees (5 
feet per table 18.810.1) and allows for adjustments to street standards to protect trees, habitat areas, and other existing 
natural feature (section 18.810.030.7) . Section 18.81 0.070.C allows adjustments to planting strip widths to protect 
existing trees and natural features. Currently the City adheres to standard specifications for street widths from curb to 
curb regardless of existing trees and natural features. The City does actively allow adjustments to sidewalk and planter 
strip standards in order to preserve trees. Finally, the five foot standard planter strip width limits the selection of large 
stature street trees due to the high li kelihood of tree root damage to curbs and sidewalks. There are currently no street tree 
planting specifications such as the use of root barriers aimed at reducing future tree root conflicts . 
..... ~------------------------------
Cil} of Tiganl Urban l;orcSi ry Code Rc,·isiom I \"olumc \ ' I .114 
City of Tigard I Urban Forestry Master Plan Appendix 
APPENDIX H 
Findings from City of Tigard Policy Framework: 
• The Comprehensive Plan complies with State and Regional requirements and contains two (2) goals and 
22 policies specific to urban forestry that must be adhered to when developing other urban forestry plans or 
ordinances which affect land use. 
• The Zoning Map implements the Comprehensive Plan, and frames the type and intensity of development for 
various areas of the City. Code provisions in Chapter 18.500 provide specification for development based on 
development in the various zones. These Development Code provisions may have the greatest impact on the extent 
of tree and forest retention during development. 
• Tree and forest related Code provisions are scattered throughout the Municipal Code and the Development Code. 
Some of the Code provisions in the Municipal Code and Development Code conflict. 
• Tree provisions in Chapter 7.40 (Nuisances) of the Municipal Code address hazardous trees and vegetation. 
There is lack of specificity in the provisions, thus limiting their ability to be enforced. There is also no program 
established to abate immediate hazards. 
• Chapter 9.06 (Trees on City Property) of the Municipal regulates public trees. The Chapter contains definitions 
and requirements that conflict with those in the Development Code. The Chapter and associated Tree Manual also 
lack specificity regarding when the Code provisions are applicable and how they can be met. 
• Chapter 9.08 regulates the City's Heritage Tree Program and is a functional Chapter. 
• Many Chapters in the Development Code contain aspirational statements regarding tree and habitat preservation, 
but few implementing provisions that specifically require preservation. 
• Chapters 18.620 (Tigard Triangle Design Standards) , 18.630 (Washington Square Regional Center Design 
Standards) and 18.640 (Durham Quarry Design Standards) contain provisions that increase the type and size of 
landscaping in these districts. Some of the provisions within the Chapter conflict. 
• Chapter 18.745 (Landscaping and Screening) specifies street tree, parking lot tree, buffer tree, and other 
landscaping requirements during development. The Chapter lacks a level of specificity to ensure that trees are 
properly installed, protected, and maintained after development. Planting and maintenance provisions differ from 
those in the Municipal Code, and parking lot tree requirements have not been successful at providing long term 
canopy. 
• Chapter 18.775 (Sensitive Lands) protects steep slopes, drainageways, floodplains, and wetlands from development. 
Trees and forests located on sensitive lands are therefore protected as well . 
• Chapter 18.790 (Tree Removal) regulates tree removal and replacement during certain types of development 
projects. Some development such as development in sensitive lands and building additions are not subject to the 
Chapter's provisions even though there is significant likelihood that trees will be impacted. 
• Some of the definitions within Chapter 18.790 are inconsistent with those in the Municipal Code and lack clarity 
making them difficult to administer. 
------------------------------~ ..... 
City of Tigard Urban Forestry Code Rc,·isions I \' olume \' I 315 
Urban Forestry Master Plan Appendix I City of Tigard 
APPENDIX H 
• Mitigation for tree removal on an "inch for inch" basis is required by Chapter 18.790, and seen as excessive by 
many in the development community. It also contributes to overplanting of trees. 
• The fee in lieu of mitigation tree planting is $125 per caliper inch, which is also seen by developers as excessive. 
The methodology used to create the fee in lieu is not well defined and has resulted in many questions as to its 
legitimacy. 
• There is a loophole in Chapter 18.790 that some developers have exploited by removing trees from a site, waiting 
one year, and then submitting a development application in order to avoid tree mitigation requirements. 
• Incentives for tree preservation in Chapter 18.790 are not appealing or practical for developers. 
• Tree Removal permits are required for trees in sensitive lands by Chapter 18.790, but the approval criteria do not 
require preservation as long as erosion is adequately controlled. 
• Penalties for illegal tree removal in Chapter 18.790 can be challenging to apply when the condition and species of 
the tree removed are not known. 
• The tree replacement guidelines in Chapter 18.790 lack specificity and are difficult to administer, especially with 
regards to species and spacing requirements. 
• Throughout the Code, tracking of protected trees is a continual challenge in the years and decades after 
development is complete. 
- r-------------------
City of Tigard Urban l;orcstry Code Rc,·isiom I \ 'olumc \' I .116 
City of Tigard I Urban Forestry Master Plan Appendix 
CITY OF TJGARD, OREGON 
TIGARD CITY COUNCIL 
RESOLUTION NO. 09- ~pCj 
A RESOLUTION ACCEPTING THE CI1Y OF TIGARD'S URBAN FORESTRY l\1ASTER PLAN 
APPENDIX I 
\VHEREAS, the Urban Forestry Master Plan supports the City Council's Goal of implementing the Comprehensive 
Plan;and · 
WHEREAS, an analysis of past and current urban forest conditions and City management practices was completed 
to identify program strengths, weaknesses, opportunities, and constraints; and 
WHEREAS, urban forestry surveys, interviews, meetings and workshops were completed to identify stakeholder and 
community preferences; and 
WHEREAS, the Urban roresrry Master Plan was completed by the Citizen Advisory Committee appointed by 
Council; and 
WHEREAS, Planning Commission reviewed the Urban Forestry Master Plan and found it to be consistent witb and 
supportive of the Comprehensive Plan; and 
WHEREAS, Council has reviewed the Urban Forestry Master Plan; and 
\VHEREAS, Lhe Plan before Council sets realistic timclincs and provides a balanced framework for implementing 
updates to the City's urban forestry codes, policies and progmms. 
NOW, THEREFORE, BE IT RESOLVED by the Tigard City Council that 
SECTION 1: 111e Council accepts the City ofT~gmd's Urban Forestry Master Plan (E.--.hibit A). 
SECTION 2: This resolution is effective immediately upon passage. 
PASSED: n,;, J () {1_'- <by o[~,.,l,n_ 2009. 
ATTEST: 
Lt-f/~ . ,_~ A~~,) 
City Recorder - City ofTig:u:d 
RESOLUTION NO. 09 - 01 q 
Page 1 
________________________________ ...._ 
City of Tigard Urban Forestry Code Rc,- isiom I \'olume \' I 3 17 
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