Manejo e seu efeito na forma, estrutura e crescimento de povoamentos de Pinus taeda no sul do Brasil

Abstract

Different methodological approaches can be considered in order to increase the flexibility of the models and more accurate estimates. This thesis is composed of four papers, and to do so, two group of data were used, both from Pinus taeda stands located in Santa Catarina, southern Brazil. On papers 1, 3 and 4, data was from a trial with nine treatments varying planting density and thinning. On paper 2, data was from a trial testing four thinning intensities. In both cases trials, there were treatments with no thinning and with varying thinning intensities. On paper 1, a generalized mixed model was developed. The model was flexible and yielded good predictions on a variety of planting densities, thinning, ages, site and sociological position. On paper 2, a generalized tapper model was developed. The variable sociological position was included as the exponent and the algebraic restriction method was used to constrain the function up to the diameter at 6 meter height. On paper 3, a simultaneous basal area growth model compatible to prediction and projection was developed. On the model, it was inserted a variable describing the stand homogeneity, by a system of equations describing stand variability on the diameter distribution. On paper 4, stand maximum density was calculated in relation to the number of individuals and maximum basal area. Next, a stand density management diagram was developed to analyze thinned and un-thinned stand growth from the year 5 to 33, linking this information with the mortality observed between the thinning operations. The general results show that the generalized models presented accurate estimates in papers 1, 2 and 3. In addition, the stand density management diagrams make it possible to analyze the most appropriate moments of intervention, maintaining the growth trajectory close to the optimal management zone.