Abstract: 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.

Abstract: The implication of quinones in decay resistance of teak wood is controversial. To better understand the role of individual quinone in this property, we studied the correlations between this latter and the content of 2-(hydroxymethyl)anthraquinone, tectoquinone, anthraquinone-2-carboxylic acid, 1,4-naphthoquinone, lapachol and the new compound 4’,5’-dihydroxy-epiisocatalponol found in teak wood. Then, we studied the fungicidal activities of these quinones in comparison to acetone/water extracts from teak heartwood and sapwood and also with the commercial biocide tebuconazole. Broth dilution technique was used to assess the toxicity of these compounds against Trametes versicolor and Poria placenta. Decay resistance was measured according to current standards and individual quinones content were quantified by high performance liquid chromatography. High positive correlations were found between teak decay resistance and the content of 4’,5’-dihydroxy-epiisocatalponol, tectoquinone, 2-(hydroxymethyl)anthraquinone. Whereas no correlation was found with anthraquinone-2-carboxylic acid, lapachol and 1,4-naphthoquinone. Concerning the fungicidal activities of teak wood extractives, acetone/water heartwood extract was toxic against the two fungi while that of acetone/water sapwood was only fungistatic. 1,4-naphthoquinone and 4’,5’-dihydroxy-epiisocatalponol from the naphthoquinones family were fungicide. However, lapachol and all studied anthraquinones (2-(hydroxymethyl)anthraquinone, anthraquinone-2-carboxylic acid and tectoquinone) were fungistatic or not toxic. In the present study, 1,4-naphthoquinone was found the more toxic with a fungicidal activity 1000-times lower than that of the commercial biocide and over 2000-times lower than that of acetone/water heartwood extracts. These results show that decay resistance of teak wood could be mostly due to the content of naphthoquinone, particularly to that of 1,4-naphthoquinone indicating that it could be used as a potential wood preservative for lesser durable species.

Abstract: The variability of natural durability contributes to the bad perception of some wood end-users. In our search, we need to adjust our methods and strategies to estimate natural durability and extract higher value from wood resources. Architectural analysis is essentially a detailed, multilevel, comprehensive and dynamic approach to plant development. Numerous biological process which impact some wood properties like durability are linked with tree development. A better understanding of the interelationship between tree physiology through tree achitecture analysis and natural durability could be an approach to predict this property. This study explore the relation between the crown architecture, decay resistance and wood extractives in Dicorynia guianensis in order to propose tree crown architecture as an evalution decay resistance tool.