Forest species diversity in upper elevation hardwood forests in the Southern Appalachian Mountains

• Published in: Castanea 1997-03, Vol.62 (1), p.32-42
• Main Authors: Elliott, K.J. (USDA Forest Service, Southern Research Station, Otto, NC.), Hewitt, D
• Format: Article
• Language: English
• Subjects: BIODIVERSIDAD; BIODIVERSITE; BIODIVERSITY; Creeks; Forest ecosystems; Forest management; Forest regeneration; Genera; Overstory; Species; Species diversity; species richness; Trees; Watersheds
• ISSN: 0008-7475; 1938-4386

Overstory, shrub-layer, and herb-layer flora composition and abundance patterns in eleven forest sites were studied to evaluate species diversity and richness before implementing three types of harvest treatments. The sites were within the Wine Spring Creek Watershed and were classified as high elevation, dry, Quercus rubra-Rhododendron calendulaceum based on McNab and Browning's Landscape Ecosystem Classification system. Evaluation of species diversity was determined by Shannon-Weiner's index of diversity (H′) and Pielou's species evenness index (J′). Overstory H′ based on tree density ranged from 1.62 to 2.50 and H′ based on tree basal area ranged from 0.94 to 2.22. The importance values for woody species, showed four species that occurred on all sites (Acer rubrum, Quercus rubra, Amelanchier arborea, and Castanea dentata) accounted for 32 to 84% of overstory abundance. Shrub-layer$H^{\prime}{}_{\text{Density}}$ranged from 0.64 to 2.33 and$H^{\prime}{}_{\text{BA}}$ranged from 0.40 to 2.26. Rhododendron calendulaceum and Castanea dentata were the only species present on all sites and accounted for 28.5 to 92.3% of the shrub-layer abundance. Herb-layer$H^{\prime}{}_{\text{Density}}$ranged from 1.72 to 3.02 and$J^{\prime}{}_{\text{Density}}$was low, between 0.5 and 0.6 on most sites. Herb-layer diversity was determined by a few dominant species. Although species richness ranged from 51 to 73, seven genera of understory herbs [Prenanthes trifoliata, Thelypteris noveboracensis, Viola hastata, Medeola virginiana, Solidago (curtisii and arguta), and Carex spp., and Aster spp.] occurred on all sites and accounted for 50 to 91% of the total density and 27 to 75% of the total cover. Early successional species were well represented at all sites. Seedling survivorship, germination, and overstory contribution of seeds, caused varied site representation of species. This study provides base line data for observing variation in species richness and diversity that will result from experimental harvest methods.