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Thermal modification is a technique that can be used to increase the resistance of wood to the biodeterioration processes. In this context, the objective of this study was to evaluate the durability of Parkia pendula (angelim-saia) and Simarouba amara (marupá) woods thermally modified in rotting field tests and by the action of natural weathering. The tests were carried out in the Brazilian Amazon region, in the Mato Grosso State. The thermal modification of the wood was set with four treatments: control (T1); electric-oven treatment, 180°C for 3 h (T2); combination of autoclave and electric-oven, 125°C for 3 h, and 180°C for 3 h respectively (T3), and immersion in vegetable oil, 180°C for 3 h (T4). The samples were partially buried for the field rotting assays, and the mass loss and deterioration index were seasonally evaluated after the experiment was installed. These analyses were performed on the same samples which has been exposed to rotting essays. The action of natural weathering was assessed through the CIELAB* colour system. T4 was the most efficient for increasing the resistance to biological deterioration, under the tested conditions. T2 and T3 treatments conferred higher colorimetric stability for both types of woods after natural weathering, under the tested conditions. [ABSTRACT FROM AUTHOR]

The resistance of particleboards, made from wood, bamboo and rice husk, to fungi and termites was evaluated. Panels were composed of 100% wood (Eucalyptus grandis), 100% bamboo (Bambusa vulgaris), 100% rice husk (Oryza sativa), 50% wood and 50% bamboo; and 50% wood and 50% rice husk. Panels exposed to the decay the brown-rot fungus (Gloeophyllum trabeum, and the white-rot fungus (Trametes versicolor), and, in a choice feeding trial, to termites (Nasutitermes corniger). The rice husk particleboards had the highest resistance of all samples and the bamboo particleboards had the lowest resistance. T. versicolor fungi produced a larger mass loss in the particleboards than did G. trabeum. [ABSTRACT FROM AUTHOR]

The knowledge about lignocellulosic compounds strength to the attack of microorganisms is essential for preventing deterioration and also for knowing the correct usage of the material. Accordingly it was evaluated the natural resistance of wood panels made of particles of wood (Eucalyptus grandis) and/or bamboo (Bambusa vulgaris) to decay fungi. Particleboards were produced in laboratory, each of them with dimensions 50x50x0.95cm and density pre-set at 0.70g cm-3, in proportions of 100:0, 75:25, 50:50, 25:75 and 0:100 of wood and bamboo, respectively. The particles mass represented 91% of the dry mass of each panel while the remainder was formed by the urea-formaldehyde adhesive (8%) and paraffin (1%). The panels were tested in the laboratory and Gloeophyllum trabeum (brown rot) and Trametes versicolor (white rot) were used to determine the natural resistance to attack by wood decay fungi. It was observed that panels which were made with a mixture of particles of wood and bamboo were less resistant to attack by decay fungi. Panels that were made from bamboo or wood only showed similar biological resistance. Among fungi, T. versicolor was the one that attacked panels more severely. [ABSTRACT FROM AUTHOR]