ABSTRACT
This study was carried out to determine the longitudinal residual strain (DRL) resulting from growth stress in standing trees, in different clones of Eucalyptus spp. Twelve clones of 9-year-Eucalyptus spp. were selected by basal area (G). From each clone, 12 trees of each clone were selected, and the following variables were measured: basic density (DB), bark thickness (EC), diameter at breast height (DBH) and total height (H). The measurements of DRL were performed in living trees, using an extensometer (Growth Strain Gauge), according to the CIRAD-Fôret method. Readings were taken at four locations around the tree trunk. In relation to the levels of DRL, the results obtained in the study indicated that the clones showed large variations among themselves, presenting values considered high ones when compared with the results found in literature. The clone 8 was distinguished by having the lowest levels of strain and was considered as a suitable and recommended material for the production of solid wood and for breeding programs. On the other hand, the clone 1 showed the highest values of the DRL. There were variations in the DRL, along the circumference of the trunk of trees, and it was more pronounced in the East heading line. Analyzing the correlations between variables, it was found that the DRL values were significantly correlated with EC, DAP and the standing tree volume (VOL).
Keywords:
deformations; extensometer; breeding; wood quality