An Attempt to Reduce Collapse Through Introducing Cell-Wall Deformations
Keywords:Cell-wall deformations, slip planes, collapse, internal checking, eucalypts
The possibility of reducing collapse through the inducement of cell-wall deformations in the wood of 1939 regrowth Eucalyptus regnans F. Muell. prior to drying was investigated. Four groups of end-matched specimens from eleven logs were used. One group served as the control and the other three were subjected to predetermined loads in compression parallel-to-the-grain.
Cell-wall deformations (physical dislocation of the cell wall as a result of longitudinal compression) were induced in all treated groups, and the number of deformations was positively correlated with the compression load. However, the compression treatment had no significant effect on recoverable collapse, the total number of internal checks, nor the total area of checking before reconditioning. Physical alterations to cell walls, therefore, did not appear to have improved the way the wood dried. Additional results suggested that internal checks may be initiated by collapse in the early stages of drying, and that their later enlargement could be attributed to drying stresses.
Chafe, S. C. 1986. Radial variation of collapse, volumetric shrinkage, moisture content, and density in Eucalyptus regnans F. Muell. Wood Sci. Technol. 20(3): 253-262.nChafe, S. C. 1987. Collapse, volumetric shrinkage, specific gravity, and extractives in Eucalyptus and other species. Part 2: The influence of wood extractives. Wood Sci. Technol. 21(1):27-41.nChafe, S. C., J. E. Barnacle, A. Hunter, J. Ilic, R. L. North-way, and A. N. Rozsa. 1992. Collapse: An Introduction. CSIRO Division of Forest Products, National Library of Australia.nDadswell, H. E., and I. Langlands. 1934. Brittle heart in Australian timber: A preliminary study. J. CSIR, Australia 7:190-196.nDadswell, H. E., and I. Langlands. 1938. Brittle heart and its relation to compression failures. Empire For. J. 17:58-65.nDinwoodie, J. M. 1968. Failure in timber. Part 1. Microscopic changes in cell-wall structure associated with compression failure. J. Inst. Wood Sci. 21:37-53.nHillis, W. E., A. D. K. Hardie, and J. Ilic. 1973. The occurrence of brittle heart in Eucalyptus grandis in Zambia. Pages 485-493 in Proc. IUFRO Div. 5 Meet., South Africa, 1973, Vol. 2.nHudson, W. M. 1961. The effect of pre-compression on the static and impact bending strength of wood. Wood. Jan. 1961:18-20.nKeith, C. T. 1971. The anatomy of compression failure in relation to creep-inducing stresses. Wood Sci. 4(2): 71-82.nKeith, C. T., and W. A. Côté Jr. 1968. Microscopic characterisation of slip lines and compression failures in wood cell walls. Forest Prod. J. 18(3):67-74.nKisser, J., and A. Steininger. 1952. Makroskopische und mikroskopische Strukturandergungen bei der Bie-gebeanspruchung von Holz. Holz Roh-Werkst. 10(11): 415, cited by Keith and Côté (1968).nKitahara, R., J. Tsutsumi, and T. Matsumoto. 1984. Effect of static-bending load on the mechanical behaviour of wood. J. Japan Wood Res. Soc. 30(7):522-529.nRobinson, W. 1920. The microscopical features of mechanical strains in timber and the bearing of these on the structure of the cell wall in plants. Royal Society of London, Phil. Trans. (B)210:49-78.nTiemann, H. D. 1915. Principles of kiln drying. Lumber World Review Jan. 15 and Sept. 25.nWardrop, A. B., and H. E. Dadswell. 1947. Contribution to the study of the cell wall. 5. The occurrence, structure, and properties of certain cell wall deformations. CSIR Bulletin, Australia 221:5-31.nYang, J. L. 1990. The occurrence of brittleheart in Eucalyptus regnans and its effect on various wood properties. The University of Melbourne, Australia, 241 pp.n
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