Extratos naturais como alternativa para a preservação de madeiras

Abstract

Among the decomposing agents, the xylophagous organisms are the main ones responsible for great damages in the production of wood. The use of chemical products, for an extended time, has the implication of the emergence of more resistant lineages and the toxicity to the environment. Due to this, efforts have been directed in the search for natural compounds originating from the secondary metabolism of plants, that can act as preservatives agents of the wood. Thus, the objective of the present research was to evaluate the performance of natural extracts as an alternative for the preservation of wood. The work is based on the following steps: analysis of the toxicity of the extracts by means of fungitoxic evaluations and verification of the anti-termite activity; exposure of autoclaved samples to accelerated rotting and termite feeding preference; use of rotting field tests to evaluate the efficiency of conventional and homemade methods in the impregnation of the extracts. After exposure, all wood samples were evaluated for their biological, physical, chemical and mechanical properties, using as a parameter of comparison with two controls, positive = treated with CCB and negative = natural resistance. The results indicate that both extracts presented toxicity to the main xylophagous organisms. However, in the evaluation of the treated and exposed wood, the Neem emulsion presented variation in the results, being sometimes inefficient in the treatment or presenting negative effect in the samples. On the other hand, the tannin presented potential in most evaluations, indicating the possibility of the use of the extract in the preservation of wood.