We compared aboveground net primary productivity (ANPP), intercepted photosynthetically active solar radiation (IPAR), and radiation use efficiency ( = between a mixed deciduous forest and a white pine (Pinus strobus L.) plantation in the southern Appalachian Mountains. We also examined patterns of foliage acclimation to intra-canopy light gradients, which may influence the photosynthetic radiation use efficiency (PhRUE) of forest canopies. The mixed deciduous forest had significantly greater ANPP and than the pine plantation. There was no significant variation in across the elevation gradient in either forest. Specific leaf area of foliage was acclimated to intra-canopy light gradients. Nitrogen content and Amax was higher in overstory trees and new pine foliage than in understory trees and one-year-old pine foliage, respectively. We found no such difference in the plasticity of SLA. Radiation use efficiency may be conservative for specific forest types across a range of environmental conditions in the southern Appalachian Mountains.