Growth and bole quality responses to thinning in a red oak-sweetgum stand in southeastern Arkansas: nine-year results

Science-based guidelines for thinning in southern bottomland hardwood stands are inadequate. To address this need, we established a series of thinning studies based on stand density management in hardwood stands on minor streambottom sites across the South. In the third study in this series, four thinning treatments were applied to a poletimber-sized, red oak-sweetgum (Quercus spp.-Liquidambar styraciflua) stand in southeastern Arkansas in September 1999: (1) unthinned control; (2) light thinning to 70 to75 percent residual stocking; (3) heavy thinning to 50 to 55 percent residual stocking; and (4) B-line thinning to the recommended residual stocking for bottomland hardwoods. By the end of the ninth year after treatment, thinning had improved stand-level basal area growth but with no differences among the three levels of thinning in the rate of growth. Thinning also had increased diameter growth of residual trees, especially red oaks, but the magnitude of diameter growth response by red oaks did not differ among the three levels of thinning. The increased diameter growth of residual trees accelerated the rate of stand development through rapid increases in the number of red oak sawtimber trees per acre and rapid increases in quadratic mean diameter. The number of epicormic branches on the butt log was high and did not differ statistically among treatments.