Assessing wood quality of borer-infested red oak logs with a resonance acoustic technique

Large numbers of black oak (Quercus velutina Lam.) and scarlet oak (Quercus coccinea Muenchh.) trees are declining and dying in the Missouri Ozark forest as a result of oak decline. Red oak borer-infested trees produce low-grade logs that become extremely difficult to merchandize as the level of insect attack increases. The objective of this study was to investigate the use of a resonance-based acoustic technique to evaluate the wood quality of infested red oak logs before processing as measured by grade, type and location of defects, and mechanical properties of the resulting boards. Principal component and canonical correlation analyses revealed that relationships do exist between log acoustic measurement and board grade yield, and between a linear combination of log acoustic velocity and diameter at breast height and a linear combination of board defect measurements. Although the acoustic technique was found capable of assessing wood quality at a stand level, the major advantage of the technique lies in segregating logs within the stand.