Thinning to improve growth, bole quality, and forest health in an Inonotus hispidus-infected, red oak-sweetgum stand in the Mississippi Delta: 10-year results

A 55-year-old red oak-sweetgum (Quercus spp.- Liquidambar styraciflua) stand on the Delta National Forest in western Mississippi was subjected to a combination of low thinning and improvement cutting in 1997. Special emphasis was placed on removing all red oaks infected with Inonotus hispidus, a canker decay fungus that causes severe degradation and cull. Stand-level growth during the 10 years since thinning has been minimal. Thinning significantly increased diameter growth of residual trees, especially red oaks, but has not yet produced a significant increase in stand-level quadratic mean diameter. Thinning had little influence on the production of new epicormic branches on residual red oaks, but it greatly increased the number of epicormic branches on residual sweetgum trees. Because it removed all red oaks infected with Inonotus hispidus, thinning improved overall forest health. During the 10 years since the thinning operation, thinning has had no adverse effects on the incidence of new infections by a variety of pathogens.