Fig. 5

(A) Historical vegetation (1870s to 1880s) interpreted in 2018 to 2019 from General Land Office surveyor field notes made in 1870 to 1916 (98% were from 1870 to 1900) for points at section corners, (B) existing vegetation types from satellite imagery interpreted by LANDFIRE (www.landfire.org), and (C) soil orders within the Palouse Prairie–forest ecotone in Idaho and Washington, USA, as mapped for Whitman County, Washington, by Donaldson (1980), and for Latah County, Idaho, by Barker (1981). Soils and vegetation types are useful indicators of past vegetation (Neiman 1988; Hironaka et al. 1991). Because forest and prairie soils differ, and those differences persist long after vegetation has changed, soils could be used as indicators of where to strategically target conservation and restoration of prairie, savanna, and forests. Many pine savanna sites with low density of trees that were historically 100%, 75%, or 50% ponderosa pine (A) are now in the Conservation Reserve Program because they were marginally productive for agriculture and subject to high soil erosion. Forests were historically most likely found on alfisols and andisols, while pine savanna was historically more likely to exist on mollisols and alfisols that were in close proximity