Resistência natural de sete madeiras amazônicas a fungos xilófagos em ensaio de laboratório

Abstract

This study aimed to evaluate the natural durability of seven Amazonian woods, arurá vermelho, louro gamela, louro preto, marupá, sucupira preta, sucupira vermelha, tanimbuca, submitted to the accelerated decay test in laboratory with the fungi Gloeophyllum trabeum, which causes brown rot; and Pyconoporus sanguineus, which causes white rot. The species were previous analyzed by macroscopic wood anatomic analysis to confirm the provided identification. The samples remained in contact with the fungi during 12 weeks and after this period the percentages of mass loss were calculated, classified according to the degree of natural resistance and evaluated according to the susceptibility to attack. The means of the results were compared by the Tukey test at 5% of significance. The macroscopic anatomical analysis of the species allowed to confirm the identification at the genus level for the species, arurá vermelho (Iryanthera sp.), louro gamela (Sextonia rubra), louro preto (Ocotea sp.), marupá (Simarouba amara), sucupira preta (Diplotropis racemosa), sucupira vermelha (Andira parviflora), and tanimbuca (Buchenavia sp.), indicating that the identification provided by the company was adequate for the material supplied. Regarding the natural durability of the Amazonian woods tested, the results were inexpressive, in which the specie Simarouba amara was the most susceptible to deterioration during the 12 weeks of testing, and obtained a mass loss of ~25% for the fungus G. trabeum, being considered of moderately resistant according to the rating provided by the AWPA E30-16. The louro preto wood had the second highest mass loss (4%), followed by the other species, where no significant difference was observed. It was observed that the mass losses obtained were not very expressive when compared to those found in other studies, The mass loss of marupá wood subjected to the fungus P. sanguineus was close to 4%, classifying the wood as highly resistance to the respective fungus, however, the data obtained differ from those found in the literature, where marupá is commonly classified as moderately to non-resistant. The other species were classified as highly resistant. Future studies with other fungal cultures are recommended to obtain more expressive data.