Resistance to xylophagous organisms in <i>Eucalyptus</i> clone wood intended for sawn products

Environmental concerns have promoted the use of reforestation woods to meet industrial demands. However, these woods have less biological resistance than tropical forest species. Thus, this study aimed to evaluate the effects of density, holocellulose, lignin, extractives and wood ash from <i>Eucalyptus</i> hybrids intended for producing sawn timber, on the biological resistance to fungi and xylophagous termites under laboratory conditions. Five <i>Eucalyptus grandis</i> x <i>Eucalyptus urophylla</i> clones, with different proportions of parents and one <i>Eucalyptus grandis</i> x <i>Eucalyptus camaldulensis</i> clone, were tested against fungi and xylophagous termites. Brown rot (<i>Gloeophyllum trabeum</i>, <i>Rhodonia placenta</i> and <i>Neolentinus lepdeus</i>) and white rot fungi (<i>Trametes versicolor</i>) were tested, as well as <i>Nasutitermes corniger</i> (no-choice feeding and choice feeding tests), and drywood <i>Cryptotermes brevis</i>. Biological resistance to fungi was influenced by density, extractives and ash. The wood was classified as moderately resistant, resistant and highly resistant to fungi. The wood had moderate attack and close-to-intense damage in the no-choice feeding test with termites. However, the wood had low resistance in the choice feeding test. The clones were moderately attacked in relation to drywood termites, with low mass loss and high mortality. Clones C and F were the most resistant to the xylophagous tested.