Variation of Specific Gravity in Plantation-Grown Trees of Bigleaf Mahogany

Abstract

As a prelude to tree improvement work in the genus Swietenia, a study was made of specific gravity variation within the bole of six plantation-grown trees of bigleaf mahogany. Variation was appreciable, from 0.36 to 0.65 , and several patterns were determined. Specific gravity of the tree increased with growth rate, as expressed in diameter at breast height, but not with relative length of radius at a given height in a particular tree. It increased outward from the pith; but it was high at the base dropped markedly to a minimum at eight feet, then increased to near the base of the crown. There was no clear correlation with direction, but in these trees the wood at heights of 22 and 29 feet is heavier along the west radius. Tree specific gravity can be estimated from specific gravity at the pith at 1-foot height, r = 0.618, or from core specific gravity and growth, as expressed by diameter breast high and merchantable height, r=0.987.

Citation

Briscoe, C. B.; Harris, J. B.; Wyckoff, D. 1963. Variation of Specific Gravity in Plantation-Grown Trees of Bigleaf Mahogany. Carribean Forester 24(2):67-74.