Changes in vegetation structure and composition in response to fuel reduction treatments in the South Carolina Piedmont

Fuel reduction treatments are helpful to restore ecosystem structure and function to forests that historically sustained frequent, low-intensity fires. But the impacts of these treatments on Piedmont forests are not well understood. We examined the effects of prescribed burning, thinning, and a combination of burning and thinning on community composition of Pinus taeda/Pinus echinata forests in the South Carolina Piedmont to identify changes in community structure and species composition. Overstory basal area was reduced across all treatments. The combination of thinning and burning resulted in a substantial increase in sapling density, whereas the burn-only decreased slightly after 3 years. Seedling density for all tree species increased across all treatment units during the same time span. In addition, cover of grasses and forbs increased in the burn-only and thin + burn treatments. Treatments appeared to affect understory life forms differently with the burn-only treatment encouraging forb cover while the thin + burn treatment promoted shrub and graminoid abundance. Non-metric multidimensional scaling (NMS) indicated rapid changes in understory composition for the burn-only and thin + burn treatments, whereas the thin-only treatment showed a more gradual shift over time.