Site preparation burning to improve southern Appalachian pine-hardwood stands: vegetation composition and diversity of 13-year-old stands
Stand restoration of low-quality, mixed pine-hardwood ecosystems containing a Kalmia Zatifolia L. dominated understory, through cutting, burning, and planting of Pinus strobus L., is common on xeric southern Appalachian forest sites. We examined the effects of this treatment on early vegetation composition and diversity. Four 13-year-old stands were examined. Two of the four stands were mechanically released at age 6. Density and basal area were estimated for understory and overstory components, and density and percent cover for the herb component. Species diversity (Shannon-Wiener index) was estimated and comparisons were made between layers, sites, and treatments (release vs. nonrelease). Diversity estimates were 3.19, 1.74, and 2.45 for the herb, shrub, and overstory layers, respectively, across all sites and treatments. For perspective, comparisons were made with an untreated reference stand that was typical of stands receiving site preparation burning in the southern Appalachians. Overstory and herb diversity estimates were significantly lower for the reference stand than for the 13-year-old stands.