Natural durability of wood of exotic and native forestry species.
Studies aiming to determine the durability of wood help in the definition of parameters to predict the useful life of the products based on this material, allowing in this way to make indications of use of the wood in a reliable way. In view of the above, the objective of this study was to evaluate the natural durability of five forest species, three of which are native (Tetrorchidium rubrivenium, Maclura tinctoria and Parapiptadenia rigida) and two exotic species (Hovenia dulcis and Tectona grandis). The wood samples were installed in the rotting field by the completely randomized design, where they remained exposed for a period of 240 days, and every 60 days samples were collected in order to abstain the influence of time in the deterioration of the material. As samples were collected, they were sent and stored in the climatized room, with a temperature of 25° C and relative humidity of 60%, where they were maintained until reaching a constant mass, to verify the loss of mass and rate of deterioration. All species submitted to the rotting field trial showed high natural durability. Forest species showed high resistance to loss of mass at the end of 240 days of exposure. In the visual analysis the deterioration index indicated a moderate attack in the species Tetrorchidium rubrivenium, Maclura tinctoria and Hovenia dulcis, light to Tectona grandis and without indicative of attack to Parapiptadenia rigida.