Lumber Recovery from Gypsy Moth-Killed Red and White Oak Trees

A study was undertaken to evaluate the utilization potential of insect-killed oak trees for lumber production. Red and white oak control trees, trees dead less than 1 year, 2 to 4 years, and over 5 years were harvested to determine the lumber yield and quality. Specific gravity and moisture content measurements were taken on each dead tree and no large reductions in heartwood specific gravity were measured in either species. The reduction in sapwood specific gravity was caused by advanced wood decay and this condition was not evident in the heartwood zone of the dead trees. Sapwood and heartwood log moisture content decreased, whereas butt log moisture content increased as time from tree death increased in both species groups. Red and white oak lumber recovery factor (LRF) decreased as time from tree death increased. Red and white oak control LRF values decreased from 7.07 and 5.75 to over 5 years dead LRF values of 5.06 and 4.42, respectively. Percent overrun decreased to about 20 percent for trees dead 2 years for both species. A decrease in the percentage of high grade lumber recovery was observed for red oak trees dead over 2 years. Five-year-dead red oak logs graded Fl, F2, and F3 produced No. 1 Common and Better lumber yields of 36.7, 24.4, and 6.8 percent compared to live control yields of 72.2, 57.1, and 33.5 percent, respectively. However, no large differences in white oak lumber quality were observed with time since tree death and this was attributed to the general low quality of the white oak trees harvested in this study. For both species groups, the loss in lumber quality and lumber recovery as time after tree death increased was attributed to the drying checks, wood decay, and wood borer defects. Based on observations made, in this study, it is recommended that stands in central Pennsylvania containing dead oak trees be harvested within a period of 1 year after tree death to minimize lumber production problems and grade losses.

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