The Effect Of Ray Tissue On The Specific Gravity Of Wood
Rays, important tissues in all woods, may comprise as much as one-third of the total xylem of some species. This fraction of the wood, composed mostly of short parenchyma cells, is of little advantage in the use of wood except to enhance the appearance of decorative wood. A method of estimating the specific gravity of rays from measurements on the relative amount of cell wall substance is described, and estimated specific gravities are reported for the rays of several species.
The most significant report is that rays have a higher specific gravity than the surrounding wood composed of all the various woody tissues. The conclusion drawn from this observation is that increased ray volume may contribute to increased specific gravity. Hence, selection for high specific gravity may result in selection for high ray volume, which would most probably be undesirable.
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