Characterization and Modeling of Knots in Black Spruce (<i>Picea Mariana</i>) Logs
Keywords:Knots, modeling, characterization, black spruce, dissections
A knot study on black spruce was performed on 21 trees originating from a natural stand located in Quebec. Branch (knot) frequency, distribution, and diameter along different directions in the trees were evaluated. A destructive protocol for dissection was developed to slice each knot into a series of sections for modeling the knot morphology (or internal distribution) within the log. In addition, attempts were made to establish the relationship between external branch parameters and internal knot morphology.
The study showed that there were higher numbers of knots on the southern sides of the trees than on the northern sides, but the knot diameters on average were smaller on the southern sides. This heterogeneous distribution of knots around the stem may increase the chance of finding a log rotation that is optimal for lumber grade yield when the knots are considered during breakdown.
The dissection data were smoothed with second degree polynomial equations using an SAS® program. The equations yielded knot angles and other knot dimensional characteristics. The study indicated that internal knots in black spruce logs showed large variations in their angles, but their diameters could be predicted from the external measurements. This information is particularly important for sawing and grading models that require precise diameter data.
Bodig, J., and B. A. Jayne. 1982. Mechanics of wood and wood composites. Van Nostrand Reinhold Co., Toronto, Ont. Canada. 712 pp.nBjörklund, L., and I. Moberg. 1999. Modeling the intertree variation of knot properties for Pinus sylvestris in Sweden. Proc. IUFRO WP 55.01-04 Third Workshop—Connection between Silviculture and Wood Quality through Modeling Approaches and Simulation Software. Sept. 5-12, La Londe-Les-Maures, France. 638 pp.nButler, D. A., C. C. Brunner, and J. W. Funck. 1989. A dual-threshold image sweep-and-mark algorithm for defect detection in veneer. Forest Prod. J. 39(5):25-28.nGrondin, F., and N. Drouin. 1998. OPTITEK Sawmill Simulator—User's Guide. Forintek Canada Corporation, Québec, Canada.nGrönlund, A., and S. Grundberg. 1999. The accuracy of knot models—influence on the simulated recovery. Proc. IUFRO WP S5.01-04 Third Workshop—Connection between Silviculture and Wood Quality through Modeling Approaches and Simulation Software. Sept. 5-12, La Londe-Les-Maures, France. 638 pp.nHosie, R. C. 1990. Native trees of Canada. Fitzhenry and Whiteside, Ontario, Canada. 380 pp.nJaeger, M., J.-M. Leban, P. Borianne, S. Chemouny, and L. Saint-André. 1999. 3D stem reconstruction from CT scan exams—from log external shape to internal structures. Proc. IUFRO WP S5.01-04 Third Workshop—Connection between Silviculture and Wood Quality through Modeling Approaches and Simulation Software. Sept. 5-12, La Londe-Les-Maures, France. 638 pp.nLemieux, H., M. Samson, and A. Usenius. 1997. Morphological characterization of knots in a sample of Picea abies logs. Scand. J. Forest Res. 12(1):50-56.nLemieux, H., M. Beaudoin, and F. Grondin. 2000. A model for the sawing and grading lumber according to knots. Wood Fiber Sci. 32(2):179-188.nMinistère Des Ressources Naturelles. 1996. L'industrie québécoise des produits du bois—Situation et perspectives d'avenir. Les publications du Québec. Québec, Canada. 225 pp. (In French).nMullins, E. J., and T. S. McKnight. 1981. Canadian woods: Their properties and uses. University of Toronto Press, Toronto, Ont., Canada.nNational Lumber Grades Authority. 1996. Standard grading rules for Canadian lumber. Burnaby, BC, Canada.nSamson, M., I. Bindzi, and L.-M. Kamoso. 1996. Mathematical representation of knots in tree trunks. Can. J. Forest Res. 26(2):159-165 (In French).nShalaev, V. S. 1983. Evaluation of the effectiveness of sawing spruce sawlogs oriented according to the knots. Lesnoi Zhurnal (4):70-73 (In Russian).nSAS Institute Inc. 1985. SAS® User's Guide: Statistics, Version 5 Edition. Cary, NC: SAS Institute Inc. 956 pp.nStelle, P. H., T. E. Harless, F. G. Wagner, L. Kumar, and F. W. Taylor. 1994. Increased lumber value from optimum orientation of internal defects with respect to sawing pattern in hardwood sawlogs. Forest Prod. J. 44(3):69-72.nWagner, F. G., F. W. Taylor, D. S. Ladd, C. W. McMillin, and F. L. Roder. 1989. Ultrafast CT scanning of an oak log for internal defects. Forest Prod. J. 39(11/12):62-64.nZhang, S. Y., Y. Corneau, and G. Chauret. 1998. Impact of precommercial thinning on tree and wood characteristics, and product quality and value in balsam fir. Forintek Canada Corp. Project Report No. 1108. 74 pp.n
The copyright of an article published in Wood and Fiber Science is transferred to the Society of Wood Science and Technology (for U. S. Government employees: to the extent transferable), effective if and when the article is accepted for publication. This transfer grants the Society of Wood Science and Technology permission to republish all or any part of the article in any form, e.g., reprints for sale, microfiche, proceedings, etc. However, the authors reserve the following as set forth in the Copyright Law:
1. All proprietary rights other than copyright, such as patent rights.
2. The right to grant or refuse permission to third parties to republish all or part of the article or translations thereof. In the case of whole articles, such third parties must obtain Society of Wood Science and Technology written permission as well. However, the Society may grant rights with respect to Journal issues as a whole.
3. The right to use all or part of this article in future works of their own, such as lectures, press releases, reviews, text books, or reprint books.