Last year's Western Washington dry spell claims some trees
By STEVE BROWN
Dying Douglas fir trees bear witness to the drought that hit Western Washington last summer.
Trees between 5 and 15 years old appear to be the most commonly affected, but some larger trees also show symptoms, including entirely red crowns, red tops and red branches.
Glenn Kohler, forest entomologist with the Washington State Department of Natural Resources, said the stricken trees are "really scattered." He has examined sites including Shelton, DuPont and Auburn near the Puget Sound, south to Vancouver and along the Columbia River Gorge.
In a typical year, this type of damage may have many causes, but this year it is primarily the result of an extended period with little to no rain last August and September.
"For conifers, it's critical they get water," Kohler said, "and it just wasn't available last year."
Damage has been most severe in areas with rocky soils, such as glacial outwash around the Puget Sound. Water drains quickly in these soils, and trees depend on occasional rains during the summer to replenish their water supply.
The majority of trees that DNR's Forest Health Program examined show no indication of pathogens, insects or other animals. Fortunately, he said, even in the hardest-hit stands, the majority of trees received adequate water and are unaffected.
"Some plantations have lost 10 percent of their trees, but that's as bad as it gets," Kohler said. "It's not a scenario that makes a high risk for fire, though there is indeed more fuel."
Landowners may see an increase in the number of red trees as the weather heats up, but if green trees have put out a flush of new, expanding bright needles on branch tips this spring, they are likely to survive.
The short-lived drought will likely have no long-term effects, he said. Agricultural producers shouldn't be affected at all.