Chemical Composition and Resistance to Decay of Thermally Modified Wood from Casuarina glauca and Eucalyptus camaldulensis Grown in Egypt

In Egypt, Casuarina glauca and Eucalyptus camaldulensis are main common fast growing hardwood species in plantations, which have a high potential for use in this country. In this study, thermal treatment process was used to improve the durability of these locally produced wood species as an effective mean in wood preservation. In this context, wood specimens were exposed to heat under inert atmosphere in laboratory conditions at temperature of 240°C with different durations to reach mass losses of 5, 10 and 15%. Fungal decay tests were conducted using the brown rot fungus Poria placenta and the white rot fungus Coriolus versicolor. The chemical composition of the wood and the elemental composition as well as the extractive toxicity before and after thermal modification of the wood were determined to understand the reasons for the improvement of the durability of the wood. Heat-modified wood specimens showed a significant increase in their durability against wood decomposition depending on the severity of the treatment. Wood holocellulose was found to be distinctly more sensitive to the heating process than lignin constituent did. In addition, the weight loss was increase by fungal decay and holocellulose was decreased however, the lignin ratio was increased. The results obtained in this work may provide valuable information as a way towards the use of heat treatment technology in wood preservation in Egypt.