Oak Savannas in Western New York State, Circa 1795: Synthesizing Predictive Spatial Models and Historical Accounts to Understand Environmental and Native American Influences

Abstract

This study models and maps oak savanna distribution ca. 1795 and determines how environmental conditions and Native American land use (NALU) shaped its distribution. Historical research has analyzed early landscape accounts to assess how Native Americans modified forests throughout the eastern United States. Predictive spatial modeling has sought to quantify anthropogenic and environmental drivers of forest conditions and to predict locations where NALU changed forest composition. Yet, studies have not rigorously synthesized these two methods. This research focused on oak savannas in western New York State (27,617 km2). We trained models of oak savanna distribution from historic vegetation data in relation to environmental predictors and NALU proxies. We then mapped historical accounts of oak savannas and NALU at European-American arrival and compared them to model predictions. Results suggest that 2 to 17 percent (depending on modeling technique) of the study area contained oak savanna, with a favored estimate of 3 to 6 percent. Synthesis of models and accounts suggests that oak savannas were attributable to NALU and dry environmental conditions but that NALU (specifically burning) was present at most oak savanna locations. Models of oak savanna distribution that considered proximity to Native American settlement had higher predictive performance and better predicted locations of historical oak savanna accounts, including those with descriptions of Native American burning. This study suggests that former oak savannas in the study area can be largely attributed to NALU. Furthermore, this study’s methodology and results contribute to a larger body of geographical literature on savanna landscapes. Key Words: anthropogenic burning, forests, modeling, Native Americans, oak savanna.