Estimativa de biomassa em povoamento clonal de Eucalyptus sob o manejo de talhadia aos 36 meses de idade

Abstract

Studies on the quantification of individual stem biomass are fundamental to determining the productivity of planted forests, facilitating forest management and planning activities, especially in coppice systems, which can reduce costs by up to 60% compared to high forest management. The aim of this study is to establish the best statistical models for estimating aboveground and wood biomass production, as well as questioning the use of general equations and previous rotation for Eucalyptus clones. The research was carried out in Mogi Guaçu-SP. Biomass was collected from the destructive analysis of clones, with 0.3 kg of leaves collected from each third of the canopy and branches, and discs removed at DBH (0%, 25%, 50%, 75%, and 100% with a diameter of 5 cm) of the stem, based on the total height of the tree. In the field, all aboveground compartments were weighed separately to obtain the total wet weight, while in the laboratory, each compartment was dried in a forced ventilation oven at 65°C to obtain the dry weight. Through regression analysis, adjusted equations were obtained, using total biomass and wood biomass (Bi) as the dependent variable and DBH and total height (H) of the trees as the independent variables. The Schumacher-Hall model showed the best fit for all clones, with the highest adjusted R² and the smallest standard errors of estimate. Based on this model, a general equation for wood biomass of clones on the site was adjusted, however, individual equations for each clone showed higher precision in individual biomass estimates. The adjusted equation in the first rotation of the stand overestimated the individual biomass of three clones by 22% and showed greater dispersion in clones with lower survival. Based on the results obtained, individual biomass estimation equations should be adjusted taking into account the silvicultural system and genotypes.