There is a need to establish new objective and sensitive methods for early detection and quantification of decay fungi in wood materials. Molecular methods have proven to be a useful tool within wood protection issues, however, this field is still poorly explored and so far relatively few have used these methods within the field of wood deterioration. Among the techniques used in the indirect quantification of fungi in decayed wood and building material are chitin and ergosterol assays. DNA-based methods are rarely used for identification in connection with quantification. Access to knowledge about fungal colonisation patterns in different wood substrates would allow further improvement of new products. The aim of this study was to investigate the colonisation pattern of decay fungi in wood samples after six years in soil exposure, in an EN252 test. We analysed stakes of furfurylated wood (Scots pine) with two different treatment levels, while a copper organic preservative impregnated Scots pine and Scots pine heartwood served as reference material. Samples were taken from below ground and soil surface parts of the EN252 stakes. To quantify fungi involved in wood degradation a specific and quantitative real-time PCR (qPCR) method using universal internal transcribed spacer (ITS) primers, specific for Basidiomycetes, was used. To further verify this method, the ergosterol and chitin assays were performed, together with thermogravimetric (TGA) and light microscopic analyses. The highest amount of fungal DNA, ergosterol and chitin was found in the sample rated as 4. As expected, a lower amount of DNA was found in the samples rated as 3 and 2 and even lower in those rated as 1 and 0. This difference could not be detected with the ergosterol and chitin assays which may indicate that the qPCR method is more sensitive. The results from the TGA showed that the below ground sample rated as 4 had the lowest cellulose content and the light microscopic observations showed a large variation in decay between and within the individual stakes.

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