Mechanical Properties Of Individual Southern Pine Fibers. Part II. Comparison Of Earlywood And Latewood Fibers With Respect To Tree Height And Juvenility


  • Laurence Mott
  • Les Groom
  • Stephen Shaler


Loblolly pine, stiffness, strength, microfibril angle, modulus of elasticity, ultimate tensile stress, whole tree variation, juvenile wood


This paper reports variations in mechanical properties of individual southern pine fibers and compares engineering properties of earlywood and latewood tracheids with respect to tree height and juvenility. Results indicate that latewood fibers exhibit greater strength and stiffness than earlywood fibers irrespective of tree height or juvenility. Average earlywood loblolly pine fibers had modulus of elasticity and ultimate tensile stress values of 14.8 GPa and 604 MPa, respectively. Corresponding latewood fibers had modulus of elasticity and ultimate tensile stress values that were, respectively, 33 and 73% higher. These differences are attributable to microfibril angles and pitting. Juvenility as defined by the mechanical properties of individual wood fibers is not a cylindrical cone surrounding the pith but appears to be biconical, tapering from the base to below the live crown and then again from the live crown to the apex.


Bisset, I. J. W., And H. E. Dadswell. 1949. The variation in fibre length within one tree of E. Regnans F.v.M.Aust. For. 13(2):86-96.nClarke, C. R. E. 1995. Variations in growth, wood, pulp and paper properties of nine eucalypt species with commercial potential in South Africa. Ph.D. thesis, University College of North Wales, Bangor, UK.nDuncker, B., And L. Nordman. 1965. Determination of strength of single fibers. Paperi Jaa Puu 10:539-552.nEhrnrooth, E. M. L., And P. Kolseth. 1984. The tensile testing of single wood pulp fibers in air and water. Wood Fiber Sci. 16(4):549-556.nEl-Hosseiny, F. E., And D. H. Page. 1975. The mechanical properties of single wood pulp fibers. 2. Theories of strength. Fiber Sci. Technol. 8:21.nEvans, R. 1998. Rapid scanning of microfibril angle in increment cores by x-ray diffractometery. Pages 105-116 in B. G. Butterfield, ed. Microfibril angle in wood, Proc. IAWA/IUFRO International Workshop on the Significance of Microfibril Angle to Wood Quality. Nov. 1997. Westport, New Zealand. University of Canterbury, Christchurch, NZ.nGroom, L. H., S. M. Shaler, And L. Mott. 1995. Characterizing micro- and macromechanical properties of single wood fibers. Pages 13-22 in Proc. 1995 International Paper Physics Conference. Sept. 11-14, Ontario, Canada.nGroom, L. H., L. Mott, And S. Shaler. 2001. Mechanical properties of individual southern pine fibers. I: Determination and variability of stress-strain curves with respect to tree height and juvenility. Wood Fiber Sci. 34(1): 14-27.nHardacker, K. W. 1970. Effects of loading rate, span and beating on individual wood fiber tensile properties. Pages 201-216 in D. H. Page, ed. The physics and chemistry of wood pulp fibers. Special Technical Association Publication No. 8, Tappi, New York, NY.nHartler, N., G. Kull, And L. Stockman. 1963. Determination of fibre strength through measurement of individual fibers. Sven. Papperstidn. 66(8):301-311.nJayne, B. A. 1959. Mechanical properties of wood fibres. Tappi 42(6):461-467.nJayne, B. A. 1960. Some mechanical properties of wood fibers in tension. Forest Prod. J. 10(6):316-322.nKellogg, R. M., And F. Wangaard. 1964. Influence of fiber strength on sheet properties of hardwood pulps. Tappi 47(6):361-367.nKersavage, P. C. 1973. A system for automatically recording the load elongation characteristics of single wood fibers under controlled relative humidity conditions. USDA. U.S. Government Printing Office. 1973: 1-46.nKim, C. Y., D. H. Page, F. El-Hosseiny, And A. P. Lancaster. 1975. The mechanical properties of single wood pulp fibres Part 3. The effects of drying on strength. J. Appl. Polymer Sci. 19(8):1549-1561.nLarson, P. R., D. E. Kretschmann, A. Clark, And J. G. Isebrands. 2001. Juvenile wood, formation, and properties in southern pine: A synopsis. USDA Forest Serv. Forest Prod. Lab. General Technical Report No. xx. (in press).nLuner, P., K. P. Vemuri, And F. Womeldorf. 1967. The effect of chemical modification on the mechanical properties of paper. 3. Dry strength oxidized springwood and summerwood southern pine kraft fibers. Tappi 50(5): 227-230.nMcMillan, C. W. 1968. Morphological characteristics of loblolly pine wood as related to specific gravity, growth rate and distance from pith. Wood Sci. Technol. 2:166-176.nMegraw, R. A. 1985. Wood quality factors in loblolly pine: The influence of tree age, position in tree and cultural practice on wood specific gravity, fiber length, and fibril angle. Tappi Press, Atlanta, GA 88 pp.nMegraw, R. A., D. Bremer, G. Leaf, And J. Roers. 1999. Stiffness in loblolly as a function of ring position and height, and its relationship to microfibril angle and specific gravity, Pages 341-349 in Proc. Third Workshop, Connection Between Silviculture and Wood Quality through Modeling Approaches and Simulation Software. IUFRO working party S5.01-04, September 5-12, La Londe-Les-Maures, France.nMott, L. 1995. Micromechanical properties and fracture mechanisms of single wood pulp fibers. Ph.D. dissertation. University of Maine, Orono, ME. 198 pp.nMott, L., L. H. Groom, And S. M. Shaler. 1996. A technique to measure strain distributions in single wood pulp fibers. Wood Fiber Sci. 28(4):429-437.nNavi, P. 1998. The influence of microfibril angle on wood cell and wood mechanical properties, experimental and numerical study. Pages 62-80 in B. G. Butterfield, ed. Microfibril Angle in Wood, Proc. IAWA/IUFRO International Workshop on the Significance of Microfibril Angle to Wood Quality. New Zealand. Nov. 1997. Westport, University of Canterbury, Christchurch, NZ.nPage, D. H., And F. El-Hosseiny. 1976. The mechanical properties of single wood pulp fibres. Pt 4: The influence of defects. Sven. Papperstidn. 14:471-474.nPage, D. H., And F. El-Hosseiny., K. Winkler, And R. Bain. 1972. The mechanical properties of single wood pulp fibers Part 1: A new approach. Pulp Paper Mag. Canada. 73(8): 72-76.nPage, D. H., And F. El-Hosseiny., K. Winkler, And A. P. Lancaster. 1977. Elastic modulus of single wood pulp fibres. Tappi 60(4): 114-117.nPanshin, A. J., And C. De Zeeuw. 1980. Textbook of wood technology, 4th ed. McGraw-Hill Book Company, New York, NY.nTamolang, F. N., F. F. Wangaard, And R. M. Kellogg. 1967. Strength and stiffness of hardwood fibers. Tappi 50(2):68-71.n






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