Modeling the effect of stand homogeneity on basal area growth for unthinned and thinned Pinus taeda L. stands in southern Brazil

Studies show that homogeneity among trees interferes with stand productivity, however, this information has not been incorporated into stand-level growth and yield models to assist forest managers. This paper presents a new format for basal area growth modeling, that includes the effect of homogeneity on stand productivity and was developed for unthinned and thinned Pinus taeda stands. The database came from a 3 × 3 factorial experiment with the factors of initial density (2500, 1250, and 625 trees ha⁻¹), and thinning (without thinning, moderate thinning, and heavy thinning). The diameter distribution represented by the percentile method was used to represent stand homogeneity. The diameters (located in the 10th and 63rd percentiles) were inserted into the basal area growth model, which greatly increased the precision of the estimated predictions and projections. A simultaneous basal area growth model, compatible in prediction and projection, with the inclusion of stand homogeneity, is recommended for estimating the basal area growth of Pinus taeda stands in southern Brazil.