Acoustic and elastic properties of Leucaena leucocephala wood as a function of longitudinal position in the tree trunk.
Leucaena leucocephala (leucena) is a small/medium size invasive tree, this specie has few studies about its acoustic and mechanical properties. Most of the studies are mainly focused to comprehend its invasive behavior. Beyond the tree invasive condition, the absence of knowledge about the wood mechanical properties, its limited size and its stem full of branches since small heights, favors the massive suppression of the trees and the directly discard of the wood to landfills. Considering that the wood stress and strength properties vary according to several factors, such as the tree age and the longitudinal position which the sample is removed from the tree, measuring these variations is important to characterize species. Therefore, the objective of this study, that belongs to a broader research, was evaluate the variation of acoustic and mechanical properties of leucena wood varying the height of the tree stem. The experimental design was composed by three trees, 26 faces polyhedrons were made according to different heights of these tree stem, it was considered only the useful height (before the first bifurcation) as the stem. The polyhedrons were tested through ultrasound equipment and longitudinal and shear transducers of 1,0 MHz frequency. The results indicate that there is no alteration of the acoustic and elastic properties of the leucena wood according to the variation of the longitudinal position of the tree stem. This result can be explained by the limited dimension of the useful leucena tree stem and indicates that the whole wood of this area can be fully destinate to the same purpose.