Forage production after thinning a natural loblolly pine-hardwood stand to different basal areas

Mixed pine (Pinus spp,)-hardwood forests are common in the southern United States (U.S,), but little quantitative information exists on the response of understory forage to reductions in basal area from thinning. We determined understory forage characteristics before thinning and 2 and 4 years after thinning a 35-year-old natural loblolly pine (P. taeda)-hardwood stand (initially 27 m(2)/ha of pine and 8 m(2)/ha of hardwood basal area). A combination of 3 loblolly pine (15, 18, and 21 m(2)/ha) and 3 hardwood (0, 3.5, and 7 m2/ha) basal areas was replicated 3 times, resulting in 27 0.08-ha plots. Understory coverage and forage biomass were determined on 25 understory plots systematically located within each plot, with data analyzed using analysis of variance and regression. Herbaceous forage biomass and coverage and light intensity were correlated negatively (P< 0.05) with retained pine and hardwood basal areas, with hardwood basal area being the more important factor, Stand thinning improved herbaceous forage availability for wildlife, but the response was time-dependent. Forage from woody browse and vines also increased following stand thinning, although responses were not as time-dependent as herbaceous forages, Results of our study indicate that managers can manipulate forage production by thinning stands to prescribed basal areas and compositions.