RELEASING SHELTERED NORTHERN RED OAK DURING THE EARLY STEM EXCLUSION STAGE

Abstract-The utility of releasing sheltered northern red oak was examined in mesic hardwood stands in north central West Virginia. Different levels of release were applied in the spring of 1996- six growing seasons after planting 2-0 seedlings that were protected with 5 ft corrugated plastic shelters. The planting was done in a 7.77 acre forest opening that developed abundant natural regeneration, but lacked a self-sustaining oak component. The most intensive release consisted of cutting all stems within a 5 ft radius of the sheltered tree (n = 20). A less intensive release consisted of the removal of only stems that were significantly overtopping the sheltered tree (n = 20). A control group in which the trees were not released was also incorporated into the study (n = 19). Trees at the beginning of the study either were codominant or intermediate in crown class. Total height of northern red oak prior to treatment averaged 9.7 ft and did not differ among treatments. Height growth after two growing seasons was statistically different among treatments (p = 0.0151). Average height growth was 4.09 ft and 3.96 ft for the minimal release and the control group, respectively, and 2.78 ft for the full release. Height of the competing vegetation after two growing seasons also differed by treatment (p = 0.0045) and was 16.10 ft in the minimal release, 17.88 ft in the control, and 20.80 ft in the full release. There was also strong statistical evidence that crown class distribution differed among treatments after two growing seasons (p = 0.0032). In the control group, 26 percent of the trees were newly classified as overtopped in two growing seasons. In the full release, 5 percent of the trees were overtopped and none were classified as overtopped in the minimal release. Considering the height variation between the desired tree and the competing vegetation, preliminary results indicate release operations that leave a moderate level of woody competition around trees like red oak with weak epinastic control, may prove to be the most effective at retaining a favorable competitive status of the desired tree