PHYSICAL AND MECHANICAL PROPERTIES OF THE WOOD OF Eucalyptus urophylla S.T. Blake IN THE BARK-TO-PITH DIRECTION AND ALONG THE STEM

The objective of this work was to evaluate some wood properties of a clone of Eucalyptus urophylla in the radial direction and in two positions along the trunk. The studied material came from Votorantim Metais Zinco S.A., and the plantations, located in Vazante, State of Minas Gerais, Brazil, were six years old. Six trees were harvested from which were cut two logs with three meter long each. Those logs were sawed into thick diametral slabs. A one-meter sample was obtained from these planks in the radial direction. Following this,samples were taken for the evaluation of specific gravity and apparent density, shrinkage from green or from 12% moisture, fiber and vessel sizes and static bending properties. It was foundthat basic and apparent specific gravities, total longitudinal shrinkage, fiber length, vessel diameter and moduli of rupture and elasticity tended to increase in the bark-to-pith direction,while partial longitudinal shrinkage, the tangential/radial ratios and the vessel frequency were reduced. Radial and tangential shrinkages, width, lumen diameter and fiber wall thickness showed different patterns of variation. Only partial volumetric, radial shrinkages and vessel frequency showed different values between the two logs taken from the same tree. The main correlations observed were between modulus of elasticity and of rupture with either specific gravity or apparent density and between fiber lumen diameter with specific gravity, total longitudinal shrinkage and with modulus of rupture in static bending.