With Trees As My Witness: The Use of Historical Survey Records in Understanding Contact-Era Forest Structure in the Upper Middle Fork Willamette River Watershed

Petraglia, Grace

With Trees As My Witness: The Use of Historical Survey Records in Understanding Contact-Era Forest Structure in the Upper Middle Fork Willamette River Watershed

dc.contributor.advisor	Coughlan, Michael
dc.contributor.advisor	Mossberg, Barabara
dc.contributor.author	Petraglia, Grace
dc.date.accessioned	2023-08-18T15:58:27Z
dc.date.available	2023-08-18T15:58:27Z
dc.date.issued	2023
dc.description	60 pages	en_US
dc.description.abstract	This research examined the use and limitations of United States General Land Office surveys for reconstructing historical landscape patterns. We reconstructed forest structure for three townships surveyed in 1869 and 1902 in the Upper Middle Fork Willamette watershed. Survey of the area was preceded by early Euro-American explorers, construction of the Oregon Central Military Wagon Road, and timber and grazing activity. We used historical survey notes to conduct an iterative fuzzy classification of section lines that assigned each line degree of membership to closed canopy forest. The final fuzzy classification relied on a composite index comprised of the number of witness and bearing trees recorded along each line and the average distance of each tree recorded from the line. This approach minimized research bias and mitigated the inherent limitations of historical data. Fuzzy membership was then compared with other variables derived from survey notes as well as a previously published reconstruction that uses discrete vegetation classes. Our findings show a positive relationship between survey line membership to degree of closed canopy forest and elevation. We conclude that fuzzy set theory is an appropriate method to work with GLO survey records. However, our investigation suggests that on their own, GLO survey data is insufficient in quality and reliability to confidently reconstruct historical forest structure at a spatial grain needed to inform management plans.	en_US
dc.identifier.orcid	0009-0005-6685-9357
dc.identifier.uri	https://hdl.handle.net/1794/28709
dc.language.iso	en_US
dc.publisher	University of Oregon
dc.rights	CC BY-NC-ND 4.0
dc.subject	Land surveys	en_US
dc.subject	fuzzy classification	en_US
dc.subject	reconstruction	en_US
dc.subject	forestry	en_US
dc.title	With Trees As My Witness: The Use of Historical Survey Records in Understanding Contact-Era Forest Structure in the Upper Middle Fork Willamette River Watershed
dc.type	Thesis/Dissertation