The Effects of Previous Drying on Shrinkage and Moisture Content of Some Southern Bottomland Hardwoods
Keywords:Equilibrium moisture content, fiber saturation point, shrinkage
AbstractThree logs for each of nine southern hardwood species were obtained, and specimens were separated into heartwood and sapwood. Specimens were dried from the initial green condition to oven-dry and then resaturated and dried again to oven-dry. A simple linear regression analysis was performed to determine the relationship between volumetric shrinkage and moisture content of never-dried and previously-dried specimens. The average fiber saturation point was 33.3 (33.6 for sapwood and 32.9 for heartwood) for never-dried specimens and 29.4 (28.2 for sapwood and 30.6 for heartwood) for previously-dried specimens. An average of 86% of the variability in volumetric shrinkage of never-dried specimens can be attributed to moisture content, and 90.5% of the variability in volumetric shrinkage of previously-died specimens can be attributed to moisture content. Highly significant differences for the species factor were found to exist at an equilibrium moisture content of 90% relative humidity (RH) and 75% RH for both never-dried and previously-died specimens. Volumetric shrink-age differed significantly for species and wood-types at 90%, 75%, and 0% RH for previously-died wood and 75% and 0% RH for never-died wood. A t-test revealed significant differences between volumetric shrinkage of never-dried and that of previously-dried wood for both wood-types of two species and one wood-type of three others.
Choong, E. T. 1969a. Moisture and the wood of the southern pines. Forest Prod. J. 19(2):30-36.nChoong, E. T. 1969b. Effect of extractives on shrinkage and other hygroscopic properties of ten southern pine woods. Wood Fiber 1:124-133.nChoong, E. T., and F. G. Manwiller. 1976. Dimensional and relative hygroscopic properties of hardwoods from southern pine sites. Wood Sci. 9(1):39-43.nChoong, E. T., P. J. Fogg, and C. B. Pollock. 1989. Variation in shrinkage properties of second-growth baldcypress and tupelogum. Wood Fiber Sci. 21(1): 17-29.nFeist, W. C., and H. Tarkow. 1967. Polymer exclusion in wood substance: A new procedure for measuring fiber saturation points. Forest Prod. J. 17(10):65-68.nHiggins, N. C. 1957. The equilibrium moisture content—Relative humidity relationship of selected native and foreign woods. Forest Prod. J. 7:371-377.nKelsey, K. E. 1956. The shrinkage intersection point—Its significance and the method of its determination. Forest Prod. J. 6(10):411-417.nKoch, P. 1985. Utilization of hardwoods growing on southern pine sites. USDA Forest Serv. Agric. Handb. 605, vol. 1. U.S. Govt. Print. Off., Washington. DC. 1418 pp.nKollmann, F. F. P., and W. A. Côté, Jr. 1968. Principles of wood science and technology, vol. 1. Solid wood. Springer-Verlag, New York, NY. 592 pp.nNearn, W. T. 1955. Effect of water soluble extractives on the volumetric shrinkage and equilibrium moisture content of eleven tropical and domestic woods. Penn. Agric. Exp. Stat. Bull. 598. 38 pp.nOkoh, I. K. A. 1976. Moisture sorption and electrical resistivity of some woods and barks. Ph.D. thesis, State Univ. of New York, Coll. of Environ. Sci. and For., Syracuse, NY. 183 pp.nSAS Institute, Inc. 1989. SAS/STAT User's guide, version 6, 4th ed., vol. 2. Cary, NC. 846 pp.nShupe, T. F., E. T. Choong, and M. D. Gibson. 1995a. Differences in moisture content and shrinkage between inner-wood and outerwood of a single cottonwood tree. Forest Prod. J. 45(10):89-92.nShupe, T. F., E. T. Choong, and M. D. Gibson. 1995b. Differences in moisture content and shrinkage between outerwood, middle-wood, and corewood of two yellow-poplar trees. Forest Prod. J. 45(9):85-90.nShupe, T. F., E. T. Choong, and M. D. Gibson. 1996. The effects of previous drying and extractives on shrinkage of outerwood, middlewood, and corewood of two sweetgum trees. Forest Prod. J. 46(9):94-97.nSpalt, H. A. 1958. The fundamentals of water vapor sorption by wood. Forest Prod. J. 8(10):288-295.nStamm, A. J. 1959. Method for estimating vapor sorption at fiber saturation point of wood and paper. Holz Roh-Werkst. 17(5):203-205.nStamm, A. J. 1964. Wood and cellulose science. Ronald Press Co., New York, NY. 549 pp.nSteel, R. G. D., and J. H. Torrie. 1980. Principles and procedures of statistics; A biometrical approach, 2nd ed. McGraw-Hill, Inc., New York, NY. 633 pp.nWangaard, F. F. 1957. A new approach to the determination of fiber saturation point from mechanical tests. Forest Prod. J. 7(11):410-416.nWangaard, F. F., and L. A. Granados. 1967. The effect of extractives on water vapor sorption by wood. Wood Sci. Technol. 1:253-277.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.