Ability of selected basidiomycetous fungi to decay black locust wood

Black locust (Robinia pseudoacacia L.) is a non-native tree species wide-spread all over Europe that has already gained some commercial importance. The study assessed ability of selected basidiomycetous fungi (Coniophora puteana, Heterobasidion annosum, Trametes versicolor, Fomitiporia robusta) to decay black locust wood, which was estimated determined based on the dry mass loss during a 16-week decay test. Wood samples were gathered in the Głogów Forest District (SW Poland) and represented three age classes (38, 60 and 71 years). Density of the investigated wood varied from 612 to 907 kg/m3 and significantly decreased with tree age (p < 0.001). The recorded mass loss ranged from 0.00 to 5.81%, amounting to 1.03% on average. We found that the resistance of black locust wood significantly increased with trees age (p = 0.011). Also, the observed mass loss differed significantly with regard to the investigated fungi species (p < 0.001). The highest values were recorded for T. versicolor (mean = 2.14%). Comparing two F. robusta strains, we found significantly smaller mass loss for black locust wood than for oak wood (p < 0.001). Investigated strains caused greater mass loss in wood of the species from which they had been isolated (p = 0.021 and p = 0.049 for locust and oak, respectively). Our findings confirm the assumptions of high durability of black locust wood to the fungi-caused decay.