Water-Filled Lumens In Steady-State Flow In Oak and Poplar

Authors

  • C. Arthur Hart

Abstract

In white oak (Quercus alba, L.) and yellow poplar (Liriodendron tulipifera, L.), steady-state moisture profiles between either 100% or 97% relative humidity and 71% relative humidity were determined by slicing samples perpendicular to the direction of moisture diffusion. Both the shape of the moisture profiles and the magnitude of the moisture contents (exceeding 40% in some oak samples) indicated the presence of water-saturated lumens in both species. Most of these saturated lumens occurred above 20% MC, but in the oak some of them evidently persisted to moisture contents well below 20%. This resulted in a moisture-content gradient that was steeper than the actual hygroscopic gradient for the oak and thus can lead to misinterpretations in comparing oak diffusion coefficients with poplar values. The presence of collapse was indicated by the presence of excessive shrinkage in some specimens of both species, particularly in one group of oak samples. This strongly supports the Tiemann theory of capillary tension collapse.

References

Choong, E. T. 1965. Diffusion coefficients of softwoods by steady-state and theoretical methods. Forest Prod. J., 15: 21-27.nComstock, G. L. 1963. Moisture diffusion coefficients in wood as calculated from adsorption, desorption, and steady state data. Forest Prod. J., 13: 97-103.nEllwood, E. L. 1952. The seasoning of rotary peeled veneer from Eucalyptus regnans F.V.M. Austral. J. of Appl. Sci., 3(1): 53-70; also, Austral. Div. of Forest Prod. Rept. No. 158.nErickson, R. W., J. Haygreen, and R. Hossfeld. 1966. Drying prefrozen redwood with limited data on other species. Forest Prod. J., 16(8): 57-65.nHandbook Of Chemistry and Physics. 1955. Chemical Rubber Publishing Co., Cleveland.nKelly, M. W., and C. A. Hart. 1969. Water vapor sorption rates by wood cell walls. Wood and Fiber, 1 270-282.nMartley, J. F. 1926. Moisture movement through wood. The steady state. Great Britain Department of Scientific Industrial Research, Forest Products Research Tech. Paper No. 2.nNearn, W. T. 1955. The effect of water soluble extractives on the volumetric shrinkage and equilibrium moisture content of eleven tropical and domestic woods. Penn. State Univ., Bull. 598, School of Forestry Series, No. 2.nSchneider, A. 1960. Diagramme zur Bestimmung der relativen Luftfeuchtigkeit. Holz als Roh- und Werkstoff, 18: 269-272.nSmith, H. H. 1956. Relative humidity and equilibrium moisture content graphs and tables for use in kiln drying lumber. U. S. Dept. Agr., Forest Serv., Forest Prod. Lab. Rept. No. 1651, Madison, Wisconsin.nStamm, A. J. 1959. Bound-water diffusion into wood in the fiber direction. Forest Prod. J., 9: 27-32.nStamm, A. J. 1964. Wood and cellulose science. Ronald Press, New York.nTarkow, H., and H. D. Turner. 1958. The swelling pressure of wood. Forest Prod. J., 8: 193-197.nTiemann, H. D. 1951. Wood technology. 3rd ed. Pitman Publishing Corp., New York.nWood Handbook. 1955. Agriculture Handbook No. 72. U. S. Govt. Printing Office, Washington, D. C.n

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Published

2007-06-22

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Research Contributions