MANAGEMENT OF INDIVIDUAL TREE DIAMETER GROWTH AND IMPLICATIONS FOR PRUNING FOR BRAZILIAN Eucalyptus grandis Hill ex Maiden

Resumo

In the present work a thinning program and a model describing dynamic of crown base recession for Eucalyptus grandis was established on an individual tree basis. Therefore, 485 trees were measured on temporary plots in forests of the companies Klabin Riocell (Guaíba), Todeschini (Cachoeira do Sul), the Federal University of Santa Maria and Aracruz Company, located in Rio Grande do Sul, Espirito Santo and Bahia, Brazil. A straight relationship between crown width and diameter at breast height (DBH) was found by using regression analysis. The equation obtained was crown width = e^{0.504+0.0307* DBH}, with a coefficient of determination of 0.78 and a standard error of 0.034. With this equation the standing space of the individual trees was calculated over the whole rotation period, taking into account a crown cover of 70 %. Therefore the number of trees which can be grown on a hectare was derived for different variants of management systems aiming to produce eucalypt sawlogs in short rotation periods. Beside this a multivariate model describing height of crown base as a function of DBH and total height was found. Based upon this model the dynamics of crown base recession for different site qualities and thinning regimes are described, giving advice for time and intensity of green pruning.