INCIDENCE OF DECAY ABOVE THE GROUNDLINE IN DOUGLAS-FIR POLES IN THE PACIFIC-NORTHWEST

The occurrence of decay at the groundline of Douglas-fir poles is well documented, but not its occurrence above the groundline. In this stud y, 496 Douglas-fir poles in Oregon and Washington were inspected 1.5, 3.0, and 4.5 m above the groundline. Decay fungi were isolated from th ese poles in regions with both high and low precipitation, with the gr eatest incidence in coastal regions and around Puget Sound. The incide nce of decay was extremely low in poles less than 10 years old but inc reased in those between 10 and 20 years old. Decay fungi were isolated from all three sampling heights at about the same frequency, an indic ation that conditions were suitable for fungal growth along the entire length of the pole. The results suggest that aboveground decay is pre valent in Douglas-fir poles in this region and should be considered in wood-pole maintenance programs.