Durabilidade natural da madeira de cinco espécies amazônicas submetidas a ensaios de deterioração de campo

Abstract

This work aimed to evaluate the deterioration of wood from five Amazonian species from the North matogrossense submitted to the ground in the open environments and forest. Being selected for such wood species Apuleia leiocarpa (garapeira), Erisma uncinatum (cedar), Mezilaurus Itauba (itaúba), Parkia pendula (angelim skirt) and Trattinnickia rhoifolia (Amescla). Bodies were prepared with dimensions equal to 2 x 2 x 30 cm, which are buried up to half of its length (15 cm). Evaluations consisted in repetitions every sixty days when six specimens of each species, for each environment, were subjected to Rockwell hardness tests, static bending (modulus of elasticity and modulus of rupture), and the quantification of weight loss. Yet it was conducted chemical analysis of the samples taken in the fourth month of exposure, to determine the changes in this period. For each of these characterizations were made an initial assessment as a witness. When evaluating the final results, it was observed that the three species of medium and low specific mass basic (Amescla, angelim skirt and cedar) showed greater weight loss and consequently greater reduction in mechanical strength to the stress tests, which It can be attributed to attack xilófago organisms such as fungi and termites, since the chemical analysis showed significant reduction in the holocellulose content. Regarding the two kinds of high specific mass (garapeira and itaúba), these showed low weight loss and consequent higher mechanical resistance, which can be related both to their respective masses specifies higher, as to its high content of extractives.