Rot resistance of tropical wood species affected by water leaching

Initial water leaching affects were studied relative to the rot resistance of 21 tropical wood species to the brown-rot fungus Coniophora puteana and the white-rot fungus Trametes versicolor. The rot resistance of tropical woods, determined by their weight loss (∆m) at 6-weeks fungal attack, was differently influenced by the initial water leaching, as follows: in the 1st group of eight durable species (dark red meranti, macassar ebony, cerejeira, merbau, santos rosewood, zebrano, wengé, and karri) there occurred a very significant decrease of their high rot resistance (with statistical confidence in the range 99 to 99.9% for different species); in the 2nd group of 10 durable species (ipé, yellow balau, doussié, bubinga, ovengol, padouk, iroko, blue gum, maçaranduba, and makoré) there did not occur a decrease of their high rot resistance; and in the 3rd group of three less durable species (okoumé, tineo, sapelli) a weaker rot resistance did not change due to leaching. The durable tropical woods (18 species from the 1st and 2nd groups) were more resistant to the brown-rot fungus (∆mC.p.-average = 0.72%) than the white-rot fungus (∆mT.v.-average = 1.07%). However, this phenomenon was no longer apparent after water leaching (∆mC.p.-Leached-average = 2.61%; ∆mT.v.-Leached-average = 2.32%).