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ASTORIA, Ore. (AP) - Coastal state forests are experiencing a resurgence in Swiss needle cast disease, a fungus that kills the evergreen needles on Douglas fir trees by interrupting the process of photosynthesis.
Aerial surveys conducted by the Oregon Department of Forestry show 338,543 acres infected by the disease — almost double the 2004 total, The Daily Astorian newspaper reported.
The fungus thrives in warm, wet conditions on the coast. The disease turns needles yellow before the tree "casts" them off. The fungus doesn't kill the trees, but it reduces their growth rate by 20 percent to 50 percent.
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