231 Years of Vegetation Change at Chestnut Ridge Natural Area Preserve, Virginia, USA

Abstract

Forests in the Appalachian Mountains have experienced shifts in forest composition and structure because of modifications to disturbance regimes and introductions of non-native species. To quantify these impacts at Chestnut Ridge Natural Area Preserve (CRNAP) in southwestern Virginia, we compared witness trees recorded in historical land survey records with present-day vegetation samples of trees and shrubs. In 1794, white oak (Quercus alba, importance value [IV] = 32%) and black oak (Quercus velutina, IV = 24%) dominated the overstory. By 1923, the overstory had shifted to chestnut oak (Quercus montana, IV = 31%) and American chestnut (Castanea dentata, IV = 21%). In the present-day, northern red oak (Quercus rubra) and chestnut oak dominate the overstory with IV of 14% and 13%, respectively. Historically, American chestnut was more likely to grow next to other tree species (historical mingling index =0.5); whereas in the present-day, after the introduction of the chestnut blight, American chestnut was more likely to grow next to other American chestnut (present-day mingling index = 0.2). Comparisons across the strata of present-day vegetation provide evidence of mesophication at CRNAP because the oak-dominated overstory co-occurs with a midstory and understory dominated by mesic species including great rhododendron (Rhododendron maximum), red maple (Acer rubrum), and sourwood (Oxydendrum arboreum). The comparison of historical and present-day woody species at CRNAP reveals a dynamic forest with shifts in composition and structure that reflects impacts of timber harvesting and the introduction of chestnut blight.