Community analysis of preservative-treated southern pine (Pinus spp.) using terminal restriction fragment length polymorphism (T-RFLP) analysis. Part 2: Bacteria field study

The effects of wood preservatives on the bacterial community in southern yellow pine were assessed by the molecular method ‘terminal restriction fragment length polymorphism’ (T-RFLP). Stakes, treated with 0.25% and 0.37% ammoniacal copper quat (ACQ-C), 0.1% and 0.25% chlorothalonil (CTN), 0.1% and 0.25% CTN with 2% butylated hydroxytoluene (BHT), and 2% BHT were installed with untreated controls in two field test sites in Mississippi and sampled every 90 days. Bacterial DNA was amplified by means of general 16S rDNA primers. Community data were analyzed to determine the effects of test site, exposure (above or below ground), treatment concentrations, and exposure time on the bacterial communities inhabiting the field stakes. Wood preservatives altered the bacterial communities, which fluctuated in numbers and composition over time. Initial exposure to CTN changed the pattern of species that colonized the stakes, and the bacterial communities did not become more similar to controls after CTN depletion. Bacterial communities on untreated controls were the most similar to each other and changed the least over time. Preservative treatment led to greater population turnover and increased diversity by creating a more unstable bacterial environment, which prevented these communities from reaching equilibrium. Although preservative treatment led to changes over time, there were still many shared species within and between the untreated controls and the different preservative treatments.