In 1996, the Oregon Dept. of Forestry mapped the extent of the disease by aerial survey. The Oregon Department of Forestry's 1997 aerial survey increased this area to nearly 393,000 acres. The unexpected nature and severity of the epidemic has mobilized private, state and federal foresters to join forces . Pooled resources are currently funding intensive research to shed light on the nature of the current epidemic and possible solutions. Tree holding one year's needles.
Summer wood is darker and more dense.
Because of severe defoliation, diseased trees concentrate resources toward foliage production in the spring. In late winter and spring these pseudothecia emerge from the stomata of previous year's needles. The upper needle is healthy, the lower one is infected with P. gaeumannii. Most pseudothecia ripen and release ascospores in late March through June. Sporulation continues through August.