Avaliação da madeira e da polpação kraft em clones de eucaliptos

Abstract

Low cost and high quality cellulose production demands appropriate wood. The selection of superior clones has been done based on some criteria as basic density, gravimetric yield of pulping and wood chemical composition, especially of cellulose, hemicelluloses, extractive and lignin contents. This study aimed at evaluating the characteristics of the Eucalyptus wood, by destructive methods, and the Kraft pulping production in six clones. Five 3-year-old trees of s each clone, planted in a spacing of 3.0 x 3.3 m, were sampled in Cocais, Guanhães, Rio Doce and Santa Bárbara, in Minas Gerais State, Brazil. The basic density was measured in disks collected at 1.3 m from the ground (DBH) and in whole tree chips (composed sample). The chemical composition was measured in sawdust samples, taken from DBH. The pulping was carried out from whole tree chips. It was verified that the density measured in DBH was slightly superior to that measured in the whole tree chips. The general wood chemical composition was very much affected by the planting site and type of clone. Mountain sites produce wood with higher contents of cellulose and lower contents of hemicelluloses. The F clone wood from Santa Bárbara and Cocais presented lower qualities in relation to the other studied clones. The bests kraft pulping yields were achieved from the the clone B from Guanhães and Santa Bárbara.