The effects of prescribed burning by the National Park Service on pine-oak forests within Great Smoky Mountains National Park

The National Park Service (NPS) at Great Smoky Mountains National Park (GSMNP) has implemented prescribed burning of pine-oak forests in an attempt to restore and maintain this fire-dependent forest type, which is converting to a mesic broadleaf forest after a long period of fire suppression. One goal of the burning is to create suitable habitat for the red-cockaded woodpecker, a federally endangered species that requires a habitat with open stands possessing mature pines. The effects of prescribed burns on two pine-oak forests were measured and evaluated to determine their effectiveness in achieving management goals. Hemispherical photography analysis quantified the impact of burning on available light reaching the forest floor with the global site factor (GSF), the percentage of total above-the-canopy light reaching the forest floor. A site which received a high intensity burn had canopy coverage substantially reduced resulting in more light penetration compared with a site which received a low intensity prescribed burn and unburned control sites. Pine regeneration was abundant only in the forest at the location receiving the high intensity burn. Available light had a significant relationship with the species composition of tree regeneration. Substantial pine regeneration and recruitment into larger size classes was associated with levels of GSF that were 60 percent or greater, providing a novel, empirical criterion for management of this forest type. On the low intensity fire site, hardwood regeneration increased following the fire, indicating that the low intensity fire actually accelerated succession to a more mesic forest type. Future fires in pine-oak forests at GSMNP should be of sufficient intensity to reduce the canopy to the extent that GSF is 60 percent or greater following the burn in order to retain pine-oak forests.