Basidiomycete colonization in Douglas-fir poles after 3 or 6 months of air-seasoning

Basidiomycete colonization of sterile Douglas-fir pole sections was monitored over 3- and 6-month exposure periods at four Pacific Northwest sites. Basidiomycetes were isolated from 8.2 percent of cores removed from the pole sections after 3 months of exposure, which suggests that colonization occurs rapidly after the poles are peeled. Postia placenta was the most frequently isolated fungus, followed by Stereum hirsutum, Phanerochaete sordida, and Sistotrema brinkmanii. Postia placenta commonly inhabits decaying Douglas-fir poles in service. Climate conditions were not correlated with colonization rate, and site-specific climate indices were not useful for predicting the risk of fungal colonization. The lack of correlation suggests that fungal colonization of air-seasoning poles is controlled by factors other than temperature and rainfall. Douglas-fir poles are rapidly colonized by basidiomycetes and, even when air-seasoned for short periods, must be sterilized at some point during the treatment process.