Establishment of Poria carbonica in wood and colonization by basidiomycetes of Douglas-fir utility poles during air seasoning

Graduation date: 1985Influence of temperature and wood moisture content on\ud spore germination and colonization of Douglas-fir\ud (Pseudotsuga jnenziesii) heartwood by Poria carbonica\ud basidiospores and chlamydospores was studied. Both spore\ud types germinated and colonized wood at moisture contents\ud above the fiber saturation point, but not below.\ud Germination and wood colonization occurred at 22°C or 30°\ud C, but not at 5 or 35°C. Chlamydospores germinated at 5\ud and 35°C, but were unable to colonize the wood.\ud Basidiomycete colonization of air-seasoning Douglasfir\ud poles in the Pacific Northwest was studied during a 2\ud year period. Sterilized pole sections (2 and 4 ft long)\ud were exposed for 3-month intervals at four widely\ud separated sites. Basidiomycetes were isolated from the\ud pole sections by removing wood increment cores, placing\ud the cores into nutrient medium, and then culturing fungi\ud that grew from the wood.\ud Twenty-five basidiomycetes were identified from the\ud pole sections including six monokaryons (identified by\ud successful matings with known monokaryotic isolates).\ud Basidiomycete isolation frequencies were generally higher\ud during the winter months, and were particularly high in\ud the period November, 1981 to January, 1982.\ud The isolation frequency and distribution of basidiomycetes\ud in 1540 air-seasoning Douglas-fir poles from 24\ud yards in the Pacific Northwest were determined by removing\ud 14 increment cores from each pole. The poles ranged from\ud freshly cut to those seasoned over 25 months.\ud Thirty basidiomycete species including 11 with\ud monokaryons were isolated from the air-seasoning poles.\ud The frequency of poles colonized by decay fungi increased\ud from 35% following pole felling to about 90% after 18\ud months of air seasoning. Poria carbonica and 12, placenta,\ud the primary decay fungi in Douglas-fir poles in service,\ud were among the most prevalent basidiomycetes after 25\ud months of air seasoning. These species generally were\ud isolated from the heartwood where they may survive some\ud preservative treatments to initiate internal decay in\ud poles in service. Limiting the air-seasoning period to 1\ud year and sterilizing air-seasoned Douglas-fir poles,\ud especially transmission poles, during preservative\ud treatment should markedly decrease decay in poles in\ud service