This guide was prepared to assist field foresters in the use of stress wave timing instruments to locate and define areas of decay in standingtimber. The first three sections provide background information, the principles of stress wave nondestructive testing, and measurement techniques for stress‍?wave nondestructive testing. The last section is a detailed description of how to apply stress wave nondestructive testing methods to standing timber. A sample field data acquisition form is included.

Nature's engineering of wood through genetics, wind, and weather creates a wide variability in wood as a material. Consequently, manufacture and users of wood products are frequently frustrated in dealing with the forest resource. Manufacturers sometimes argue that wood is difficult to consistently process into quality products because of the wide range of properties that exist in this raw material. Users of wood products can be equally frustrated with the performance variability found in finished products. Nondestructive evaluation (NDE) technologies have contributed significantly toward eliminating the cause of these frustrations. NDE technologies have been developed and are currently used in lumber and veneer grading programs that result in engineered materials that have consistent well-defined performance characteristics. This brief volume explores some of the processes that are used to manufacture wood, including green wood technology and provides a bit of history to wood production and its uses too. Other products that may interest you from the US Forest Service can be found at this link: https://bookstore.gpo.gov/agency/819

Stress-wave nondestructive evaluation (NDE) techniques are used widely in the forest products industry--from the grading of wood veneer to inspection of timber structures. Inspection professionals frequently use stress-wave NDE techniques to locate internal voids and decayed or deteriorated areas in large timbers. Although these techniques have proven useful, little information exists concerning the relationship between stress-wave parameters and deterioration observed as a consequence of marine borer attack. In this pilot test, we examined the relationship between stress-wave transmission time and the quality of wood in Sitka spruce and western hemlock logs that had varying degrees of deterioration as a consequence of attack from marine borers. Stress-wave transmission time, perpendicular to grain, was measured at several locations on each log. The logs were then sawn into lumber, which was then visually evaluated. A relationship was observed between stress-wave transmission time and deterioration of the logs and the yield of lumber from the logs.