Woods have been protected with fungicides for a long time, and the effects of these fungicides on soil after being leached into the ground have turned out to be a true environmental issue. It is in this perspective that we are proposing to study fungal communities of these contaminated woods in a purpose of bioremediation. Most of precedent studies have focused on ability of some Basidiomycetes and white rot fungi to degrade these biocide products. Treated and reference (non-treated) woods samples have been incubated in containers of forest soil in Guyana. The first two samplings of these woods and soils have been realized five months apart. A crop and molecular study allowed us to isolate and identify forty strains of Ascomycetes able to develop on wood and resist xenobiotics. Until now, no Ascomycete was known to resist xenobiotics. Furthermore, a study of fungal communities of the woods and soil were done by D-HPLC and SSCP, and then analyzed by ACP. According to these analyses, biocides are leached in the soil and have an impact on these fungal communities, which are different depending on time of sampling and the way wood is processed.