A stress wave based approach to NDE of logs for assessing potential veneer quality. Part I Small-diameter ponderosa pine

Longitudinal stress wave nondestructive evaluation (NDE) techniques have been used in a variety of applications in the forest products industry. Recently, it has been shown that they can significantly aid in the assessment of log quality, particularly when they are used to predict performance of structural lumber obtained from a log. The purpose of the research described in this report was to investigate the use of stress-wave-based techniques for assessing the potential quality of veneer obtained from logs. Sixty-two ponderosa pine veneer blocks from 22 tree-length logs were nondestructively evaluated using longitudinal stress wave techniques. Stress wave transmission times were measured on both tree-length logs and veneer blocks. They were then rotary peeled, and the resulting veneer was dried and ultrasonically graded using commercially available grading equipment. The quality of the veneer, as determined by ultrasonic grading, was then compared with the nondestructive measurements of the logs from which they came. A strong relationship was found to exist between log and veneer nondestructive assessments.