Using prescribed fire to regenerate Pinus echinata, P. pungens, and P. rigida communities in the southern Appalachian Mountains

Southern Appalachian yellow pines [shortleaf pine (Pinus echinata), table mountain pine (P. pungens), and pitch pine (P. rigida)] require disturbance for successful regeneration. Cultural burning practices provided the disturbance that prehistorically and historically maintained these forest communities. These practices ceased in the early twentieth century when fire suppression became the primary fire management initiative of federal land managers. The last fifty years of fire suppression have degraded yellow pine habitat to the point that federal fire management plans now call for increased use of prescribed burning to restore these forests. Before fire can be effectively used for this purpose, land managers must understand the ecology of these changed systems. In addition, prescribed fire must become a more accessible management tool. This project evaluated the fire history, current structure, and species composition of selected southern Appalachian yellow pine forests as well as their response to prescribed fire. I examined these factors in seven yellow pine stands on five National Forests in the southem Appalachian region. The presence of macroscopic charcoal in soils indicated that fires burned these stands at some time in their past. Yellow pines remained overstory dominants on all sites but potential overstory dominants [chestnut oak (Quercus prinus) scarlet oak (Q. coccinea) and red maple (Acer rubrum)] predominated both midstory and understory size classes. Pre-bum pine regeneration was absent likely due to shading from a closed canopy as well as deep litter and duff accumulations. Hardwood regeneration was successful. Two of these stands burned with high intensities but four burned at medium to low intensities and two were not burned at all. Prescribed burning did not effect soil pH or soil nutrient content of these acidic, oligotrophic soils. Prescribed bums of moderate intensity and severity opened the forest canopy but encouraged sprouting of understory hardwoods. I observed yellow pine regeneration only following those bums that reduced overstory and midstory basal area and density as well as litter and duff depth. Future bums to restore yellow pine communities must be of moderate to high intensity and severity not only to open the forest canopy and expose mineral soil, but also to expose regenerative basal buds of hardwoods to lethal temperatures in order to lessen hardwood sprouting. Prescribed bums that do not promote pine regeneration may further encourage succession towards hardwood-dominated stands. Opportunities to conduct bums appropriate to the restoration of yellow pine communities, however, are rare under current prescribed burning guidelines. The number of days meeting required weather parameters are few and occur during late spring and early fall months. Before yellow pine communities can be restored, burning guidelines must change in order to make prescribed burning accessible to ecosystem managers.