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Linking log quality with product performanceAuthor(s): D. W. Green; Robert Ross
Source: Role of wood production in ecosystem management : proceedings of the Sustainable Forestry Working Group at the IUFRO All Division 5 Conference, Pullman, Washington, July 1997. Madison, Wis. : USDA Forest Service, Forest Products Laboratory, 1997. General technical report FPL ; GTR-100.:p. 53-58.
Publication Series: General Technical Report (GTR)
Station: Forest Products Laboratory
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DescriptionIn the United States, log grading procedures use visual assessment of defects, in relation to the log scaling diameter, to estimate the yield of lumber that maybe expected from the log. This procedure was satisfactory when structural grades were based only on defect size and location. In recent years, however, structural products have increasingly been graded using a combination of visual estimation of defects, coupled with nondestructive evaluation of other parameters, to obtain a more precise estimate of product properties. Today, the most commonly used nondestructive evaluation parameter is modulus of elasticity (MOE). This paper summarizes the results of three studies that used longitudinal stress wave techniques to determine the MOE of logs prior to processing into lumber. The MOE of lumber was then determined by transverse vibration. A good relationship was generally observed between the MOE of logs and the average MOE of the lumber cut from an individual log. These results indicate that improved sorting of logs for structural products might be achieved using a combination of visual assessment and determination of the MOE of the logs using longitudinal stress wave techniques. Future research will quantify the improvement in log sorting efficiency relative to other nondestructive testing options.
CitationGreen, D. W.; Ross, R. J. 1997. Linking log quality with product performance. Role of wood production in ecosystem management : proceedings of the Sustainable Forestry Working Group at the IUFRO All Division 5 Conference, Pullman, Washington, July 1997. Madison, Wis. : USDA Forest Service, Forest Products Laboratory, 1997. General technical report FPL ; GTR-100.:p. 53-58.
KeywordsLog grade, longitudinal stress wave, modulus of elasticity, lumber, spruce, balsam fir, Douglas-fir, western hemlock, Southern Pine.
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