Modeling the historical distribution of American chestnut (Castanea dentata) for potential restoration in western New York State, US

Abstract

American chestnut (Castanea dentata) once held great economic and ecological importance in eastern US forests before its demise due to an invasive blight fungus. Backcross breeding and genetic engineering methods are currently developing a blight-resistant tree with mostly American chestnut traits. With the potential reintroduction of chestnut, research has sought to understand the geographic distribution of chestnut to locate potential restoration sites, but less research has compared ideal restoration sites to underlying land ownership. This research models the historical distribution of chestnut in western New York State (NYS, approximately 27,617 km2), containing a portion of the original range of chestnut, in order to determine suitable areas for chestnut reintroduction. This study models chestnut distribution using original land survey record (OLSR) data (ca. 1797–1799 CE) and species distribution models (SDMs), then compares model predictions to current protected lands. Results indicate that depending upon modeling technique, predicted suitable habitat for chestnut ranges 27.9–49.7% of the study area, and that 8.0–11.5% of suitable area is within protected land parcels. SDMs suggest that within the study area, the two predictors most important to chestnut distribution are soil pH and terrain slope, with chestnut favoring acidic soils and steeper slopes. By identifying sites for potential reintroduction of chestnut, this study highlights that reintroduction will depend upon cooperation of private landowners along with governments and non-governmental agencies. This study offers a revision to the historical distribution of chestnut in western NYS, and provides insight into land ownership and management issues facing its restoration.