Print PageLongleaf pine ecosystems once dominated the southeastern United States prior to European settlement but have since undergone a dramatic reduction from their original extent. In the Fort Benning military installation near Columbus GA, remnant stands and plantations of longleaf pine are being managed by applying frequent, low-intensity fires with the aim of maintaining diversity in the ground cover layer. Our objective was to assess the diversity of the ground cover vegetation in longleaf pine stands of different ages. We established four 1 ha plots in five stands each belonging to a different age class: 5 years, 12 years, 21 years, and 87 years-of-age. We sampled the ground cover layer on a monthly basis using 1 m2 temporary quadrats. Percent cover and number of species per plot of green understory vegetation were determined and separated into shrubs, seedlings, grasses, forbs, ferns, and moss categories during the winter of 2012.
Results/Conclusions
Our preliminary results show overall a higher number of green species in the 5 year-old and 87-year-old plots compared to the 12 and 21 year-old plots during winter months. The youngest and the oldest plots had a higher average number of grasses, forbs, and shrubs than the intermediate ages. Grass species included Andropogon spp. and Dichanthelium spp. Percent cover of grasses was greater in the 5 year-old and in the 12 year-old stands than in the oldest two stands. Forb cover was highest in the 21 year-old plot due to the abundance of the fire sensitive Pityopsis graminifolia, which was almost the only forb present in that stand. Species diversity and ecophysiological traits associated with species dominance and productivity will be examined. Potential ecophysiological traits include photosynthetic capacity, dark respiration rate, chlorophyll fluorescence, stomatal conductance, foliar δ13C, instantaneous water-use efficiency, leaf nitrogen concentration, specific leaf area, leaf dry matter content, and leaf phenology.
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