Lumber characteristics 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 one year, two to four years, and over five years were harvested to determine the lumber yield, drying characteristics, and quality. Red and white oak lumber recovery factor (LRF) decreased with increased time after death. A decrease in the percentage of high grade lumber recovery was observed for red oak trees dead over two years. However, no large differences in white oak lumber quality were observed with time after tree death and this was attributed to the general low quality of the white oak trees harvested in this study. The loss in LRF and lumber grade was attributed to the drying checks, wood decay and wood borer defects observed in dead logs. The drying characteristics were evaluated for gypsy moth-killed red and white oak trees and compared to live trees from both species groups. The 4/4 lumber was scaled and graded before and after drying to 7% moisture content using three schedules: a regular kiln schedule, air dried to 20% moisture content then kiln dried by the regular kiln schedule, and a mild kiln schedule. The drying times were similar for both species using the regular and mild kiln schedules. The red oak lumber from trees dead 2-4 years and 5 years and longer had significantly more surface checks, ring failure, and significantly less warp than did the lumber from the control trees. Red and white oak lumber from trees dead 5 years and longer showed a significant loss in upper grade lumber after drying using a regular kiln schedule. This grade reduction was minimized in both species groups by using a mild kiln schedule. 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 one year after tree death to maximize lumber production and minimize grade losses.

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