Monitoring Diversity and Colonization Patterns of Wood-Inhabiting Fungi Using Field Stake Tests
P Torres-Andrade, J Cappellazzi, J J Morrell
Advances in molecular identification of microbial communities enabling rapid microorganism determination have allowed ecological data to be increasingly incorporated into standardized wood performance tests. Combining standard field tests with molecular methods to study wood-associated microflora can help to better understand fungal colonization and decay processes of wood in service. The potential for using DNA-based identification techniques to examine changes in diversity and community composition of wood-inhabiting fungi was assessed in ground-contact field stake tests at the Starker Post Farm research site located near Corvallis, Oregon, USA. Field stakes of red alder (Alnus rubra), Douglas-fir (Pseudotsuga menziesii) sapwood and western red cedar heartwood (Thuja plicata) were installed and a subsample collected every 3-months (long-term exposure; LTE) or installed and replaced every 6-months (short-term exposure; STE) over a two-year period. Isolated, pure-culture fungi were sequenced and identified by comparison to the GenBank database using BLAST. A total of 384 fungal isolates were recovered and identified from 54 stakes. Eleven basidiomycete isolates were identified, with Peniophora limitata and Phanerochaete livescens occurring most frequently. The most common ascomycetes were Phialophora mustea and Cadophora sp. Species richness differed between the LTE and STE tests, while fungal diversity in both exposure tests remained constant. In contrast, diversity decreased with longer exposures. Short term variations in temperature and precipitation were the most significant environmental gradients influencing fungal community composition of stakes in ground contact. The results will be used to better understand fungal ecology and microbial colonization processes.
Keywords: fungal community, wood colonization, wood ecology, wood decay, Douglas-fir, red alder, western redcedar