Long-Term Vegetation Changes in Coweeta Basin, Southern Appalachian Mountains, a USDA Forest Service Experimental Forest

We used permanent plot inventories of the Coweeta Basin (USDA FS Experimental Forest), Southern Appalachian Mountains of North Carolina (first sampled in 1934 and again in 1969-72 and 1988-93) to describe the distribution of species along an environmental gradient. We also explored the influence of large-scale disturbance on this deciduous forest. Chestnut blight fungus (Endothia parasitica) is an invasive species, which severely damaged populations of Castanea dentata and had widespread and long-term impacts on eastern North American forests. In 1926, local infestations of chestnut blight were reported in the Coweeta Basin; by 1930 most C. dentata trees were dead or dying from the blight. Concurrently, forests were further disturbed by lumbering, which was common across the region from the mid 1800s to the early 1900s. We used nonmetric multidimensional scaling for the analyses of the inventory periods. In 1934, C. dentata was the most abundant tree species. It was present in 98% of the plots and contributed 22% of the total density and 36% of the total basal area. By the 1970s, only sprouting stems of C. dentata remained in the forest due to chestnut blight induced mortality. The canopy dominant, C. dentata, was replaced by more than one species across the environmental gradient. Subsequently, diversity increased significantly over time and was attributed to an increase in evenness of species distribution. Quercus prinus, Acer rubrum, Cornus florida, Tsuga canadensis, and Oxydendrum arboreum increased by 2-5% across the basin following the decline of C. dentata. Tsuga canadensis increased in abundance and distribution, especially near streams across elevations. Liriodendron tulipifera replaced C. dentata in moist coves, which have low terrain shape and high organic matter content. In contrast, Q. prinus and A. rubrum were ubiquitous, much like C. dentata before the chestnut blight, becoming dominant or co-dominant species across all environmental conditions.