DETERMINATION OF CHEMICAL PROPERTIES OF WOODS FROM SOUTHERN AMAZON

The objective of this work was to make conventional analyzes to determine the chemical composition of five wooden species found on the Southern Amazon area, which are: Peltogyne lecointei, Erisma uncinatum, Hymenaea courbaril, Hymenolobium petraeum and Trattinnickia burseraefolia. First of all, the samples was collected based on the availability and and primarily in the commercial interest of the wood. It was taken discs along the stem (0%, 25%, 50%, 75% and 100% of the commercial height) from the trees randomly selected with the conditions of good stem and straight grain. Of those samples it was taken the specimens, transformed into sawdust to obtain the chemical properties of the wood. The sawdust went to the sieve of 40 ans 60 mesh, respectively, the fraction used to determine the percentage of total extractives, lignin and holocellulose through the sieve of 40 mesh, but stays retained on the shieve of 60 mesh. The evaluation of the results indicates that the chemical composition of the wooden species studied here have the values within the normal pattern for hardwoods ranging 1-5% extractives, 16-24% for lignin and 65-82% for holocellulose. The data indicates that Hymenaea courbaril has the highest basic specific mass, because the holocellulose content is inverse to the lignin. Erisma uncinatum and Hymenolobium petraeum has the highest extractive contente, which propose a higher natural durability related to the other wood species. The lignin on the tissue confers resistance to attack by wood borers, so the specie Hymenaea courbaril is possibly the most vulnerable to attack. However in the species studied here, the chemical composition of the woods can be significantly correlated with the technological behavior of these woods