Effect of Rotation Age on Lumber Grade Yield, Bending Strength and Stiffness in Jack Pine (<i>Pinus Banksiana</i> Lamb.) Natural Stands
Keywords:Jack pine (<i>Pinus banksiana</i> Lamb.), natural stands, rotation age, lumber bending properties, modulus of elasticity (MOE), modulus of rupture (MOR), basic wood density
The effects of rotation age on lumber visual grade yield and lumber bending properties were studied on 142 jack pine trees sampled in three stands located in Timmins, Ontario. The stands, aged 50, 73, and 90 years were all naturally established after forest fires. The visual grading of a total of 1720 lumber pieces showed that the 50-yr-old stand produced a slightly lower Select Structural grade yield (36.1%) compared to the older stands (73 yr 42.9% and 90 yr 39.3%). When No. 2 and Better grades were combined, the 50-yr-old stand resulted in the lowest volume yield (88.2%), whereas the proportions of No. 2 and Better for the 73- and 90-yr-old stands were comparable (93.0 and 92.6%, respectively). Downgrades due to decay were much higher in the 90-yr-old stand (20.6%) than in the 73- and 50-yr-old stands (5.2% and 0%, respectively). Regarding stand productivity, the 50-yr-old stand showed the highest annual stand increment of 5.25 m3/ha/year, compared to 3.82 and 3.21 for the 73- and 90-yr-old stands, respectively. The visual grading of 782 board pieces showed no effect of stand age on board quality. In the 90-yr-old trees, wood density decreased steadily from butt to top for all the diameter classes studied (12-30 cm).
The study showed that rotation age had a significant impact on lumber bending properties. The lumber bending properties for the 50-yr-old stand were significantly lower than those of the 73- and 90-yr-old stands. The lumber strength (MOR) and lumber stiffness (MOE) values for the 50-yr-old stand were about 16% lower and 19-16% lower than those of the 73- and 90-yr-old stands, respectively. However, no significant differences in lumber bending properties were found between the two older stands. From the viewpoint of lumber properties, a moderate rotation age of about 70 years is preferred in jack pine.
American Society of Testing and Materials (ASTM). 1997. Annual Book of ASTM Standards, Vol. 04.10 Wood. American Society of Testing and Materials, Philadelphia, PA. 676 pp.nBarbour, J., D. C. F. Fayle, G. Chauret, J. Cook, M.B. Karsh and S. Ran. 1994. Breast-height relative density and radial growth in mature jack pine (Pinus banksiana) for 38 years after thinning. Can. J. For. Res.24:2439-2447.nBarrett, J. D., and R. M. Kellogg. 1991. Bending strength and stiffness of second-growth Douglas-fir dimension lumber. Forest Prod. J.41(10):35-43.nBarrett, J.D. and W. Lau, 1994. Bending Canadian lumber properties. Canadian Wood Council, Ottawa, Ontario. 346 pp.nBiblis, E. J. 1990. Properties and grade yield of lumber from a 27-year-old slash pine plantation. Forest Prod. J.40(3): 21-24.nBarrett, J.D., R. Brinker, H. F. Carino, and C. W. McKee. 1993. Effect of stand age on flexural properties and grade compliance of lumber from loblolly pine plantation timber. Forest Prod. J.43(2):23-28.nButterfield, B. G. 1997. Microfibril angle in wood. Proc. IAWA/IUFRO International Workshop on the Significance of Microfibril Angle to Wood Quality. Westport, New Zealand. 410 pp.nClark III, A., R. H. McAlister, J.R. Saucier, and K. Reitter. 1996. Effect of rotation age on lumber grade, yield, and strength of unthinned loblolly pine. Forest Prod. J.46(1):63-68.nKennedy, R. W. 1995. Coniferous wood quality in the future: Concerns and strategies. Wood Sci. Technol.29:321-338.nMacpeak, M. D., L. F. Burkart, and D. Weldon. 1990. Comparison of grade, yield, and mechanical properties of lumber produced from young fast-grown and older slow-grown planted slash pine. Forest Prod. J.40(1):11-14.nMorris, D. M., and W. H. Parker. 1991. Variable-quality form in mature jack pine stands: Qualification and relationship with environmental factors. Can. J. For. Res.22:279-289.nNLGA. 2003. Standard grading rules for Canadian lumber. National Lumber Grades Authority, Vancouver, BC.nPanshin, A. J., and C. de Zeeuw. 1980. Textbook of wood technology. McGraw-Hill Book Company. New York, NY. 722 pp.nShepard, R. K., and J. E. Shottafer. 1992. Specific gravity and mechanical property-age relationships in red pine. Forest Prod. J.42(7/8):60-66.nSwant, G. R. 1991. A northern Ontario company's perspective on thinning and spacing. In Space to grow. Spacing and thinning in Northern Ontario. V. F. Haavisto, C. R. Smith, and C. Mason eds. Proc. Symposium, 18-20 June 1990, Sault Ste. Marie. Forestry Canada, Ontario Region, and the Ontario Ministry of Natural Resources. Joint Rep. 15.nZhang, S. Y., G. Chauret, H.Q. Ren and R. Desjardins. 2002. Impact of initial spacing on plantation black spruce lumber grade yield, bending properties, and MSR yield. Wood Fiber Sci.34(1):460-475.nZhang, S. Y., G. Chauret and Duchesne, I. 2004. Maximizing the value of jack pine resource. Canadian Forest Service Report No. 2403, Forintek Canada Corp., Sainte-Foy, Quebec.nZobel, B. J., and J. R. Sprague. 1998. Juvenile wood in forest trees. Springer-Verlag, Berlin, Germany. 300 pp.n
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