Influência da idade e da posi??o ao longo do tronco na composi??o química da madeira de Eucalyptus grandis Hill ex. Maiden

摘要

The objective of this work was to study the chemical composition variation of the Eucalyptus grandis wood, of four different ages (10,14,20 and 25 years), from commercial stands. The samples were removed from three disks taken from the base and top of the first two 3 m logs, from sixteen trees (four per age), totalizing fourty-eight discs. The mean values of holocellulose, lignin and extractive contents were 69, 27 and 4%, respectively. The extractive and lignin contents increased with age, with greater concentrations near the base; the holocellulose content also decreased with age with greater concentrations in discs removed from the upper parts of the trunk.