Abstract:
Oak savanna is believed to have existed in North America for 20-25 million years
(Barry and Spicer 1987). When Euro-Americans began settling the Midwestern United
States, oak savanna was found from Minnesota to Texas and had been relatively stable
there for thousands of years (Nuzzo 1986). Approximately 12,000,000 ha of oak savanna
were found in the upper Midwestern United States when settlement of the region began in
the early nineteenth century (Nuzzo 1986). In the Pacific Northwest, oak savanna is
estimated to have covered 500,000 ha prior to Euro-American settlement around 1850
(Vesely and Tucker 2004). Today, oak savanna is considered critically endangered in
both the Midwestern United States and Oregon's Willamette Valley (Noss et al. 1995).