A Technique for Determining The Transverse Dimensions of the Fibres in Wood
Keywords:
Measurement, fiber dimensions, fiber diameter, cell-wall thickness, cell walls, lumens, bulk density, softwoods, hardwoods, microscopyAbstract
For softwoods, fibre width can be calculated from a count by optical microscopy of the number of cells per unit area (N) in the cross-sectional face of a small block of wood. Assuming a square cross section for the average fibre, the fibre width (b) is given by b = (1/N)1/2. Lumen width (a) can be calculated from the fibre width thus obtained and a measurement of the bulk density of the wood (DB) using the theoretically derived relationship a/b = (1 - DB/DC)1/2. DC is the cell-wall density, which to a good approximation is a constant from one wood to another.
For hardwoods, the count of cells per unit area is restricted to areas occupied by the libriform fibres, and the bulk density used is that of the part of the wood occupied by these fibres. This bulk density may be calculated from the bulk density of the whole wood using a measurement of the fraction of the total volume occupied by vessels and ray cells.
The results so obtained are in close agreement with those obtained by direct measurement using scanning electron microscopy and are believed to be superior to those previously obtained by the usual expedient of direct measurement by optical microscopy. This is particularly true of cell-wall thickness, (b-a)/2, the direct measurement of which has recently been shown to be subject to many sources of error.
A simple experimental procedure for measuring the dry-bulk density of small samples of wood is described and the work is illustrated by measurements of the fibre width, cell-wall thickness, and fibre coarseness of some thirty species of wood.
References
Britt, K. W. 1965. Determination of fiber coarseness in wood samples. Tappi 48(1): 7-11.nBritt, K. W. 1966. Fiber coarseness in wood. Tappi 49(5):202-206.nHaywood, G. 1950. Effect of variations in size and shape of fibers on papermaking properties. Tappi 33(8):370-383.nIfju, G., and R. W. Kennedy. 1962. Some variables affecting microtensile strength of Douglas-fir. For. Prod. J. 12(5):213-217.nIfju, G., and P. Labosky, Jr. 1972. A study of loblolly pine growth increments. Part 1. Wood and tracheid characteristics. Tappi 55(4):524-529.nJayme, G., and T. Krause. 1963. Über die Packungsdichte den Zellwande in Laubholzern. Holz Roh-Werkst. 21(1):14-19.nKellogg, R. M., and F. F. Wangaard. 1969. Variation in the cell-wall density of wood. Wood Fiber 1(3): 180-204.nSmith, D. M., and R. B. Miller. 1964. Methods of measuring and estimating tracheid wall thickness of Redwood (Sequoia sempervirens [D. Don] Endl.). Tappi 47(10):599-604.nSmith, D. M. 1965. Rapid measurement of tracheid cross-sectional dimensions of conifers: Its application to specific gravity determinations. For. Prod. J. 15(8):325-334.nStamm, A. J. 1946. Passage of liquids, vapors, and dissolved materials through softwoods. U.S. Dep. Agr. Tech. Bull. 929, 80 pp.nStamm, A. J. 1964. Wood and cellulose science. Ronald Press, New York. 549 pp.nStayton, C. L., and C. A. Hart. 1965. Determining pore size distribution in softwoods with a mercury porosimeter. For. Prod. J. 15(10):435-440.nStone, J. E., A. M. Scallan, and G. M. A. Aberson. 1966. The wall density of native cellulose fibres. Pulp Paper Mag. Can. 57(3): T263-T268.nStone, J. E., A. M. Scallan, and P. A. V. Ahlgren. 1971. The ultrastructural distribution of lignin in tracheid cell walls. Tappi 54(9):1527-1530.nTsoumis, G. 1964. Microscopic measurement of the amount of cell-wall substance in wood and its relationship to specific gravity. Tappi 47(11):675-677.nYao, J. 1968. Modified mercury immersion method in determining specific gravity of small, irregular wood specimens. For. Prod. J. 18(12):56-59.n
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