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Changes in wood product proportions in the Douglas-fir region with respect to size, age, and time.Author(s): R.A. Monserud; X. Zhou
Source: Journal of Sustainable Forestry. 24(1): 59-83. Also In: Sustainable Forestry Management and Wood Production in a Global Economy. Deal, R.L.; White, R.; Benson, G.L., eds. Binghampton, NY: Haworth Press: 59-83
Publication Series: Scientific Journal (JRNL)
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DescriptionWe examine both the variation and the changing proportions of different wood products obtained from trees and logs in the Douglas-fir region of the Northwestern United States. Analyses are based on a large product recovery database covering over 40 years of recovery studies; 13 studies are available for Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco). Visual lumber grades were combined into four broad value classes. We used the multinomial logistic model to estimate the yield proportion of each value class as a function of age, diameter, and their interaction. We also examined changes in wood product proportions with respect to future projections of forest management, harvesting trends, and sustainability. We see a clear shift away from Appearance grades in the 1960s to Construction grades by the late 1980s. This corresponds to a concomitant shift from high-quality old-growth trees to young-growth plantations (age 50 to 60) of much smaller diameter. The projected relative proportions among the four product value classes is not expected to change much over current proportions, with Construction lumber a dominant 70 to 80 percent of the total. Thus, we expect to remain at this new equilibrium, where very little Appearance grade lumber is manufactured in the Douglas-fir region and price premiums have disappeared.
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CitationMonserud, R.A.; Zhou, X. 2007. Changes in wood product proportions in the Douglas-fir region with respect to size, age, and time. Journal of Sustainable Forestry. 24(1): 59-83. Also In: Sustainable Forestry Management and Wood Production in a Global Economy. Deal, R.L.; White, R.; Benson, G.L., eds. Binghampton, NY: Haworth Press: 59-83
KeywordsYield proportion, value class, Construction grades, multinomial logistic, Douglas-fir, Pseudotsuga menziesii
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