Structure and Diversity of Longleaf Pine (Pinus palustris Mill.) Forest Communities in the Mountain Longleaf National Wildlife Refuge, Northeastern Alabama.

The Mountain Longleaf National Wildlife Refuge (MLNWR), located in northeastern Alabama, is unique in that it holds significant acreages of young and old-growth montane longleaf pine forest (Pinus palustris Mill.). We conducted a study to aid in the management and restoration of longleaf pine communities on the MLNWR. Our objectives were to: (I) establish permanent forest monitoring plots; (2) document herbaceous and woody vegetation; and (3) measure forest diversity, structure, and fuel loads in montane longleaf pine communities with varying fire and management histories. We established 48 plots, 0.04 ha in area, in winter 2008 and measured all plots in summer 2008. The MLNWR has recently incorporated prescribed burning in their management plans and each plot was categorized by the year it was burned (2008, 2006, 2004, no-burn) and whether hardwood control treatments were applied. We identified 18, 19, and 22 different woody plant species in the overstory, mid-story, and understory, respectively, across plots. Longleaf pine basal area ranged from 5 to 10 m² ha^-1 and represented as much as 80% of basal area across plots. Mid-story basal area and woody plant species diversity were lower in plots receiving fire or hardwood control. Longleaf pine regeneration was found in only 17 plots and was highest in burned plots or plots receiving hardwood control. Burning also increased grass and herbaceous ground cover. Fuel loads were high with an average humus layer accumulation of 35 Mg ha^-1. Regular fire intervals are needed to reduce fuels and mid-story density and aid in the regeneration of longleaf pine. [ABSTRACT FROM AUTHOR]