The long-term performance of carbon-based preservatives is anticipated to be limited by detoxification through the action of microorganisms. This study identified primary colonizers of wood treated with carbon-based preservatives that may contribute to detoxification of the active ingredients. Wood coupons treated with three different carbon-based preservatives were subjected to a repeated wetting and drying cycle in an accelerated field simulator. Samples were harvested at different times: two, four, and eight weeks (16 and 32 week samples remain to be sampled). Samples were analysed by HPLC to determine the amount of chemical remaining at the surface of the sample. Chemical concentrations in the samples remained above reported toxic thresholds, and no depletion was seen between two and eight weeks. Wood slivers were chiselled from beneath the surface of the wood and plated. Isolates were identified by sequencing ribosomal DNA. Samples were dominated by bacteria that appeared morphologically similar between samples. DNA sequencing identified these isolates as a Pseudomonas species. Only three fungal isolates were found, one a Trichoderma sp., and the others are yet to be identified. Isolations and identifications will continue.