The effects of Chlorothalonil (CTN) and Butylated Hydroxy Toluene (BHT) on microbial species diversity in wood and the surrounding soil are being assessed by Terminal Restriction Fragment Length Polymorphism (T-RFLP). CTN was selected as a trial organic wood preservative, and BHT is being evaluated for its synergistic effects with CTN. Results from an accelerated decay test will be presented. The accelerated decay test evaluates the performance of wood preservatives in conditions optimized to promote accelerated microbial degradation. This study is evaluating six retentions in two different soil mixtures (with and without compost), resulting in a total of twelve treatments. Each month, one box (containing three sticks) per treatment was removed to provide thirty-six samples per sampling period. Biomechanical stress testing is being utilized to determine modulus of elasticity (MOE) as a measure of microbial degradation. TRFLP data is being analyzed to determine significant differences in patterns of microbial colonization over time due to wood preservative treatment in southern yellow pine (SYP) both in and out of soil contact. Soil samples have also been collected to observe changes in soil microbial community due to contact with preservative treated wood. Wood preservative retention is being analyzed using HPLC. Initial results show decreases in fungal and bacterial phylotype diversity for both soil contact and non-soil contact portions of preservative treated SYP wood samples compared to untreated controls. Characterization of these pattern shifts will provide a better understanding of the biology and ecology of wood decay microorganisms, the effects of biocides on the microbial community in treated wood and in the soil, and the effects on microbes on biocide breakdown and wood failure.

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