Potential of teak heartwood extracts as a natural wood preservative

This study aimed to evaluate the preservative potential of teak (Tectona grandis) heartwood extracts against decay fungi. The waste obtained in the mechanical processing of 20-year-old teak wood was used to perform extractions in hot water and absolute ethanol. To evaluate the influence of teak extracts on the natural resistance of wood, a 10-year-old teak sapwood and Pinus sp. were used. To determine the concentration of the treatment solutions, a toxicity test to the brown rot fungus Postia placenta was performed. For the impregnation, a full-cell (Bethell) treatment was conducted. Biological assays with brown, white and soft-rot fungi were performed under laboratory conditions to test the efficiency of the teak extractive solutions. The solutions containing the absolute ethanol extractives promoted the best results in the decay resistance of the treated wood and significantly changed the resistance class of the respective treated species. The resistance to soft-rot fungi was not changed.