Biomass and Taper for Trees in Thinned and Unthinned Longleaf Pine Plantations

Abstract

Abstract Longleaf pine (Pinus palustris Mill.) trees growing in thinned plantation studies in Louisiana and Texas and unthinned stands from the Louisiana sites were sampled for establishing taper, volume, and specific gravity. Stem analysis data were collected on 147 stems ranging in age from 30 to 50 yr. Analyses of covariance (ANCOVAs) were employed to determine coefficients and to detect differences among treatments, for tree taper and specific gravity. Taper and volume equation coefficients and statistics at specified ages were developed for intermediate plantation ages by examining and aging internal growth rings from the stem sections. Biomass was computed by combining the taper and specific gravity equations. Seemingly unrelated regression (SUR) was used to simultaneously fit the system of four equations composed of specific gravity, taper, volume, and biomass, because of the correlated error structure of these equations. Biomass equations, however, could not be developed for the intermediate ages because specific gravity could not be determined or related to earlier tree ages. South. J. Appl. For. 19(1):29-35.