Longleaf pine site response to repeated fertilization and forest floor removal by raking and prescribed burning
Removal of forest floor litter by pine needle raking and prescribed burning is a common practice in longleaf pine (Pinus palustris Mill.) stands on Coastal Plain sites in the Southeastern United States. Repeated removal of litter by raking and the loss of surface organic matter from controlled burns can affect the already low fertility of these sites. Although fertilization may compensate forsome nutrient losses, long-term changes in soil chemical properties may still negatively affect productivity. In this experiment, we continue work that examined the effect of burning, fertilization, and moderate and intensive litter raking on tree growth, litter production, and soil chemistry in longleaf pine stands over 6 years. This report discusses treatment response 9 years after selective thinning was initiated in a longleaf pine plantation in Aiken County, SC. Litter raking treatments, when compared to the control treatment, did not significantly affect tree height or basal area growth, although averages were larger in the fertilized litter raking treatments when compared to the non-fertilized litter raking treatments. However, longleaf pine litter production declined by up to 30 percent in both burned and raked treatments without fertilizer application compared to the unfertilized control. Fertilization significantly increased litter production on control plots, and it appeared to mitigate the reductions in needle fall on burned and raked plots. Soil nitrogen concentrations increased on fertilized and unfertilized burned and raked treatments when compared to the corresponding control. Results indicate moderate fertilization can sustain long-term litter removal and maintain soil nutrients in longleaf pine stands.