STAND DYNAMICS IN 60-YEAR-OLD ALLEGHENY HARDWOODS AFTER THINNING

Stand dynamics and tree growth in even-aged hardwood stands can be inf luenced by manipulating relative stand density, species composition, a nd stand structure. Land managers need quantitative information on the effect of vegetation manipulation to prescribe stand treatments that are appropriate for specific management objectives. Sixty-year-old sta nds composed of black cherry (Prunus serotina Ehrh.), red maple (Acer rubrum L.), sugar maple (Acer saccharum Marsh.), and American beech (F agus grandifolia Ehrh.) were thinned to 45, 60, and 75% relative densi ty as measured by the stocking guide for Allegheny hardwoods. Stand ag e, aspect, elevation, and soil-site conditions were uniform among the study plots, while relative density and to a lesser degree stand struc ture were altered by the thinning treatments. Regression analyses were used to relate stand dynamics and tree diameter growth over a 10-year period to changes in relative density, stand structure, and species c omposition. Stand growth is reported in basal area, cubic volume, sawt imber volume, and relative density growth, and individual tree respons e is reported in terms of diameter growth by species group. Study resu lts generally support current recommendations for thinning Allegheny h ardwoods for wood volume production, though stands with relatively hig h proportions of black cherry may respond better to densities greater than recommended levels for optimal sawtimber Volume production. These results also may be useful for interpreting overall stand dynamics an d developing prescriptions to enhance production of other woodland ben efits.