The purpose of this study was to compare Beta, Gamma, Johnson's SB and Weibull functions fitted by different methods for describing the horizontal structure of Khaya ivorensis (African mahogany) plantations in Brazil. The database comprised 128 plots from six plantations at varying ages. The function fits were compared using the Kolmogoroff–Smirnoff test, mean bias and mean absolute error for the number of trees and basal area per hectare per diameter class. Johnson's SB outperformed the other functions, although all functions provided an adequate fit. The best methods were method of moments and maximum likelihood fitted using 25% of the minimum observed diameter as the location parameter for the Johnson's SB function. The errors were greater in diameter classes with higher frequencies. Location and scale parameters were highly correlated with mean diameter and age for the Weibull and Johnson's SB functions, respectively, which is convenient for diameter prediction. Gamma's scale parameter had medium corr...

The insertion of stand variables allows for generalized mixed-effects height-diameter model, and the inclusion of random effects aids in model flexibility and application to new databases through calibration. This study aimed to develop a generalized mixed-effects model capable of accurately predicting the total height of Pinus taeda trees, subjected to different management regimes and at different ages.

Even though wood color is a subjective parameter, it can now be measured. Colorimetry is a technique that can be performed with specific tools, allowing a color to be identified and recorded by associating it with a numerical value. This study aims to relate the color of 11 Amazonian woods, on the tangential plane, to their basic density, using the CIEL a*b* system. The colorimetric parameters assessed were: lightness (L), red-green axis (a*), yellow-blue axis (b*), color saturation (C*), and color hue (h*), in addition to the physical parameter, bulk density. Shapiro-Wilk test, Spearman's correlation, and cluster analysis were performed to attest normality of data, correlations, and similarities between species, respectively. The grouped species showed correlations ranging from strong to weak. The strongest correlations were: (b*) positively correlating with (C*) and (a*) negatively correlating with (h*). The weakest correlations were: (L*) with (C*), and (a*) with (b*). Peltogyne sp. wood (Peltogyne sp.) did not form a group due to its peculiar colorimetric characteristics, and jatobá (Hymenaea sp.) was classified with yellowish tones and grouped as a medium-density wood, showing that high-density wood does not necessarily exhibit a dark color.