Mapping Oak (Quercus spp.) Regeneration Potential Within the Nantahala National Forest

Abstract Forest mesophication threatens the regeneration and potential future perpetuation of oak ( Quercus spp.) forests throughout southern Appalachia and eastern United States (US). We explored methods to produce stand-scale oak site suitability maps, within the Nantahala National Forest in North Carolina, which can be used to prioritize site-specific treatments to allow for oak regeneration and recruitment using silvicultural strategies to reduce forest mesophication. To establish initial conditions, USDA Forest Service common stand exam quick plot protocol was followed, and plot data collected from June through August 2023 at 180 sample points within 15 stands totaling 500 acres. Collection of seedling height class data was important for showing a gap in regeneration, between the number of small seedlings (~ 1 ft) (1038 stems) and large seedlings (> 4.5 ft) (301 stems). Two popular site suitability modeling techniques, Maximum Entropy (MaxEnt) and Random Forest, were run for five common oak species with seven predictor variables including available water capacity, elevation, eastness, ecozone, northness, soil acidity, and soil type. MaxEnt models consistently outperformed Random Forest models with the most important variables including ecozone, soil acidity, and soil type. The maps highlight locations that can be prioritized for silvicultural treatments that target regeneration and recruitment of oaks to combat or reverse forest mesophication.