Mountain longleaf pine (Pinus palustris Mill) forests are a diminishing component of the once vast longleaf pine forests of the Southeast maintained by fire. From what was perhaps the largest temperate forest type dominated by a single species of tree in the U.S. to occupying about 3% of its former range, mature longleaf pine forests are now considered rare. The Mountain Longleaf National Wildlife Refuge (MLNWR) holds significant acreages of young and old growth mountain longleaf pine. Protection and restoration of longleaf pine communities are the primary missions of the MLNWR. Because of a lack of historical information, data are needed on forest structure and fuel loads on the Refuge. Our objectives were to: (1) establish permanent monitoring plots on the Refuge, (2) document herbaceous and woody vegetation, and (3) measure biodiversity, forest structure, and fuel loads in longleaf communities with varying fire and management histories. We established 48 plots, each 0.1 ha in area. Each plot was categorized by the year it was burned (2008, 2006, 2004, no burn) and by hardwood control (HC, no HC). Shannon Diversity Index (H’), species richness, importance value (IV200), ground cover, and fuel loads were measured in the summer of 2008.
Results/Conclusions
We identified 23 and 22 different woody species in the overstory and understory, respectively. The percent of basal area in longleaf pine was as high as 80% and was highest in stands burned in 2006 and 2004 and with HC. Longleaf regeneration ranged from 0 to 24,104 stems ha-1. IV200 of longleaf pine in the understory was greatest in stands burned in 2006. There was a burn year by HC treatment interaction for H’ and species richness. Without HC, higher H’ and species richness in the overstory was observed in the 2008 and in no burn stands, which indicated greater diversity and number of hardwood species, many of which are not typically found in fire maintained longleaf pine ecosystems. These species included Acer rubrum, Carya glabra, Diospyros virginiana, Liquidambar styraciflua, and Prunus serotina. There was no difference in fuel loads by burn year; however, high humus and duff layers in all treatments indicated the lack of regular fire intervals. This study highlights the importance of fire and hardwood control in maintaining existing longleaf pine and in longleaf pine regeneration in montane ecosystems.
