Estimativa de carbono fixado na madeira de um clone híbrido de Eucalyptus urophylla e Eucalyptus grandis

Abstract

The environmental problems caused by the increase of the concentration of the greenhouse gases (GEE) in the atmosphere tend to worsen if the decision of reducing such emissions are not implemented, especially for the more developed countries. Actions in that sense should already have been taken in larger magnitude in the past. The wood production by plants is responsible for the fixation of the carbon, being a viable alternative in the reduction of CO2 level in the atmosphere and the global warming. This research aimed to estimate the amount of fixed carbon in the wood of a hybrid clone of Eucalyptus urophylla and Eucalyptus grandis. Fifty trees were sampled in three different diametric classes in six years old trees. It was determined the individual volume, the basic density and the elementary analysis of the wood of the clone. Three sampling methods were used for the determination of the average basic density of the tree. The obtained results indicate a strong variation in the estimate of dry mass among the considered diametric classes affecting the estimates of fixed carbon in the wood. There was difference in the basic density of the wood between diametric classes and sampling methods. The estimate of fixed carbon was influenced significantly by the diametric class and method used for the determination of the basic density of the wood, but not by the carbon content at the DBH nor by composed sample of several heights along the trunk. The same effect was observed in the mean increment of carbon. In a general way, the classes of 8.1 cm, 11.4 cm and 14.2 cm presented, respectively, estimates of mean annual increment of carbon ranging from 2,357.08 to 2,602.99 kg.ha-1.year-1, 4,888.95 to 5,419.33 kg.ha-1.year-1 and 8,383.32 to 9,227.88 kg.ha-1.year-1, considering 1,500 trees for hectare.