Crop Tree Release Increases Growth of Mature Red Oak Sawtimber

Abstract

Abstract Crop tree thinning plots were established in five stands of mature red oak (Quercus rubra, Q. velutina, and Q. coccinea) sawtimber in 1995. Initial stand ages ranged from 74 to 94 yr old with mean crop tree diameters ranging from 10.9 to 15.4 in. Growth of crop trees was monitored for the next 6 yr. The upper age limit at which oaks respond to crop tree management (high thinning) is at least 90 yr old. Although there was no significant difference in diameter growth between released and unreleased trees for the first 2 yr after release, diameter growth of released trees was significantly greater during each of the subsequent 4 yr. Crop tree release increased diameter growth of sawtimber red oak by 53%. Annual volume growth (International 1/4) increases ranged from 95% for 11 in. trees to 25% for 20 in. trees. Growth of crop trees has not decreased, relative to control trees, 6 yr after release. Formation of new epicormic branches on the butt log was largely limited to the slowest growing trees. Crop tree management should be considered as a method of managing sawtimber oak stands where maintaining high forest cover and noncommodities attributes are important considerations.