Resistance of in natura and torrefied Eucalyptus wood to Cryptotermes brevis (Isoptera)

Abstract

The shorter natural durability and low energy density of eucalyptus wood hampers its use in generating energy. Torrefaction or pre-carbonization, which is treatment in low oxygen with temperatures between 200 °C and 300 °C, accumulates carbon and lignin, decreases the hygroscopicity, increases the energy efficiency, and reduces the attractiveness of wood to xylophagous organisms, such as termites. The objective of this study was to evaluate the resistance of fresh and torrefied Eucalyptus urophylla (20 min at temperatures of 180 °C, 220 °C, and 260 °C) to dry wood termites (Cryptotermes brevis), following IPT standards. The torrefaction process increased the resistance to dry wood termite attack after 45 d of exposure, with mass losses five times greater in the in natura wood compared with the wood torrefied at 260 °C. The larger visual damage to the in natura chips confirmed its lower resistance to dry wood termites. Torrefaction at 260 °C increased the resistance to dry wood termites and was more efficient with a lower mass loss and wear, and caused a greater mortality of dry wood termites.