Our study sought to fine-tune knowledge about those microorganisms, particularly wood-decaying fungi degrading pollutants in situ. With a view to the depollution or bioremediation of treated woods, wood-decaying microorganisms from tropical forest soils in French Guiana and the island of Reunion were assessed for their ability to degrade toxic biocides such as pentachlorophenol (PCP) or copper chromium arsenic compounds (CCA). The degradation of red pine (Pinus resinosa) test pieces was monitored and it was found that the soil from French Guiana was more efficient than the soil from Reunion in terms of microbial activity in relation to these two biocides. A significant difference in weight loss was found for the red pinetest pieces treated with CCA and PCP, varying in a ratio of one to two (18% and 30%, respectively). In addition, a study of wood and soil fungus communities using D-HPLC and CE-SSCP, then analysed by a PCA, showed that biocide products leached into the soil had an impact on the fungus communities, which differed depending on the sampling time and on the wood treatment. Lastly, these results confirmed that CCA was less leachable and less degradable by microorganisms in these soils than PCP.