Contribution Factor of Wood Properties of Three Poplar Clones to Strength of Laminated Veneer Lumber
Keywords:Contribution factor, <i>Populus</i> sp., solid wood, laminated veneer lumber, wood properties, strength, plantation
AbstractThe term "Contribution Factor" (Cf) was introduced in this paper to indicate the contribution ratio of solid wood properties to laminated veneer lumber (LVL) strength. Three poplar (Populus sp.) clones were studied, and the results showed that poplar with good solid wood properties has high Contribution Factor. The average Contribution Factor of Poplar 69 (Populus deltoides cv. I-69/55), Poplar 72 (P. euramericana cv. I-72/58), and Poplar 63 (P. deltoides cv.I-63-51) was 76.2%, 68.6%, and 66.1%, respectively. The average Contribution Factor of the three clones for shear strength, modulus of elasticity (MOE), and impact toughness was approximately 80%, which is higher than that for modulus of rupture (MOR), compressive strength, and hardness. The average Contribution Factor of the six properties tested was highest in Poplar 69 (76.2%) and the lowest in Poplar 63 (66.1%), indicating that the Contribution Factor is positively affected by solid wood properties. Densification also significantly affects LVL MOE in Poplar 72, as compared to that of Poplar 69. Poplar 63, however, showed highest improvement in MOR strength from solid wood to LVL and also highest specific LVL MOR, even though it has the lowest solid wood MOR among the three clones.
Ambrose, J. 1994. Simplified design of wood structure. 5th ed. John Wiley & Sons, Inc., New York, pp. 213-218.nBao, F. C., and Z. H. Jiang. 1998. Wood properties of main species from plantation in China. China Forestry Publ. House, Beijing, PRC pp. 525-575.nBao, F. C., Z. H. Jiang., and S. Liu. 2000. A modeling approach to the relationship between plantation poplar properties and qualities of veneer and plywood. Scientia Silvae Sinicae 36(1):91-96.nFu, F., and F. C. Bao. 1999. End-use selection of plantation poplar: Solid wood or laminated veneer lumber. Scientia Silvae Sinicae 35(4):64-72.nHse, C. Y. 1975. Properties of flakeboards from hardwoods growing on southern pine sites. Forest Prod. J. 25(3):48-53.nHu, S. C. 1988. Cottonwood (Populus deltoides Bart.)—A bibliography 1987-1986. Bulletin 794, La. Agric. Exp. Sta., Louisiana State Univ. Agric. Center, Baton Rouge, LA.nJapanese Agric-For-Aquatic Ministry. 1989. Structural plywood. JAS (Japanese Agricultural Standard), Tokyo, Japan.nJapanese Agric-For-Aquatic Ministry., 1991 Structural laminated lumber. JAS (Japanese Agricultural Standard), Tokyo, Japan.nKretschman, D. E., R. C. Moody, R. F. Pellerin, B. A. Bendtsen, J. M. Cahilli, R. H. McAlister, and D. W. Sharp. 1993. Effect of various proportions of juvenile wood on laminated veneer lumber. Res. Pap. FPL-RP-521. USDA Forest Service, Forest Prod. Lab., Madison, WI. 31 pp.nNational Technique Monitoring Bureau of PRC. 1991. Test methods for wood physical and mechanical properties. GB 1927-1943-91 (Chinese National Standard), Beijing PRC.nPugel, A. D., E. W. Price and C. Y. Hse. 1989a. Composites from southern pine juvenile wood. Part 1. Panel fabrication and initial properties. Forest Prod. J. 40(1): 29-33.nPugel, A. D., E. W. Price and C. Y. Hse. 1989b. Composites from southern pine juvenile wood. Part 2. Durability and dimensional stability. Forest Prod. J. 40(3):57-61.nShupe, T. F., C. Y. Hse, L. H. Groom, and E. T. Choong. 1997a. Effect of silvicultural practice and veneer layup on some mechanical properties of loblolly pine LVL. Forest Prod. J. 47(9):63-69.nShupe, T. F., C. Y. Hse, L. H. Groom, and E. T. Choong. 1997b. Effect of silvicultural practice and veneer layup on some mechanical properties of loblolly pine plywood. Forest Prod. J. 47(10):101-106.nShupe, T. F., C. Y. Hse, E. T. Choong, and L. H. Groom. 1998. Effect of silviculture practice and wood type on loblolly pine particleboard and medium density fiberboard properties. Holzforschung 53:215-222.nSuchsland, O., and G. E. Woodson. 1986. Fiberboard manufacturing practices in the United States. USDA Forest Service Agric. Handbook 640, Washington, DC, p. 30.nWasniewski, J. L. 1989. Evaluation of juvenile wood and its effects on Douglas-fir structural composite panels, pages 159-173 in T. M. Maloney, ed. Proc. 23rd Washington State Univ. Intern. Particleboard/Composite Materials Symposium, Pullman, WA.nWang, S. J. 1995. Recent research on Poplar. Chinese Forestry Publ. House, Beijing PRC. pp. 1-2.n
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