Compatible Tree-volume and Upper-Stem Diameter Equations for Plantation Loblolly Pines in the West Gulf Region

Abstract

Abstract Equations are presented for predicting inside bark (ib) or outside bark (ob) cubic-foot volume to any ob diameter limit, or the ib or ob diameter at any given height, of loblolly pine tress (Pinus taeda L.) growing in thinned or unthinned plantations in the West Gulf States region. The model formulation and simultaneous estimation technique utilized ensure that the volume and stem profile equations are compatible and the parameter estimates are statistically efficient. The 230 sample trees used to develop the equations were from central Louisiana plantations and ranged in diameters at breast height (D) from 1.3 to 20.8 in. in total height (H) from 16 to 96 ft, and in ages from 9 to 55 yr. Significant differences in stem profile between trees of the same D and H in unthinned and thinned plantations suggest that separate cubic-foot volume and upper-stem diameter prediction equations should be used South J. Appl. For. 15(2):92-97