RADIAL CLUSTER OF Eucalyptus grandis BOARDS SUBMITTED TO THE CONVENTIONAL DRYING PROCESS

Abstract

The Eucalyptus sp. genus presents natural debarking and drying defects that lead to significant wood losses. For this reason, knowing the region where the defects occur may be a useful tool for those who process wood. Thus, this work aimed to radially group Eucalyptus grandis boards based on natural and drying defects. Six trees were split into boards and separated into two regions: central (C) and external (E). The central boards (C) had a higher proportion of wood from the region near the pith; and the external boards (E) had a higher proportion of wood from the region near the bark. The defects occurring in the boards dried in conventional kiln at 10% humidity were evaluated using multivariate analysis and varied in the pith-to-bark direction. The Cluster analysis separated the wood into two regions (central and external) and the principal components analysis highlighted which defects were dominant for each region. The external boards (E) presented higher bow and cupped  intensity. The central boards (C) presented higher crook intensity, knots, gum or kino bags, collapse, and superficial cracks. This information may be important for those who industrialize wood, because by knowing in which region the defect most occurs, a piece of wood may no longer be used. However, the operational factor should be taken into account, because wood characteristics, the type and conditions of the cutting equipment, pitsawing method, and sawmill layout may make it unfeasible to separate the log into two regions.