Can diameter and log end splittings be a good indicator of board end splitting in 21-year-old Eucalyptus grandis Hill ex-Maiden?

Abstract

Eucalyptus spp. are currently cultivated in Brazil. In this article we highlight Eucalyptus grandis with its potential for mechanical processing. After felling trees, the splitting that occurs at the end of logs and boards obtained during mechanical processing represents an indirect measure of the level of growth stress present in the living trees. Even though such splitting can cause significant losses in the use of wood, knowledge of this pattern is still sparse. The most suitable eucalyptus trees for the production of sawn wood can be selected by evaluating the effect of the release of growth stresses in the form of cracks. To address this gap, we herein evaluate the effects of end splitting in logs and boards, resulting from the release of growth stresses during the felling of trees and mechanical processing, as a function of the diameter of 48 Eucalyptus grandis Hill ex-Maiden trees aged 21 years old. Splitting at the ends of boards in the green and dry states have a low relationship with the diameter of the logs, but it is not related to the end splitting of the tree logs. A high positive relationship was found between dry board splitting and green board splitting. Therefore, it is possible to estimate with accuracy the evolution of green board splitting according to the drying of the wood. Boards lose, on average, 44 cm (15%) from cracks, or an average of 32 cm (11%) from growth stresses and 12 cm (4%) from drying stresses. Green and dry board splitting decreased significantly from pith to bark. The splitting of dry and green boards had no significant variation between the analyzed positions of the log along the height of the tree.