Washington Public Lands Commissioner Peter Goldmark will convene a committee of foresters, scientists and other experts in an effort to contain a pending forest health epidemic east of the Cascades.
Since the 1980s, the number of acres of trees killed by insects and disease has doubled. Over the next 15 years, state projections indicate that elevated tree mortality could occur across 2.8 million acres of Eastern Washington, or roughly one-third of the landscape.
Dead lodgepole pines already are visible in many areas, including northeast Washington’s Sherman Pass.
“The combination of the projections and the actual mortality we’re seeing causes us alarm,” said Aaron Everett, state forester for the Department of Natural Resources. “It’s certainly compounded by … what we anticipate will be a warmer climate.”
Forest pests have taken a heavy toll on other parts of the West. Mountain pine bark beetles have killed roughly 3.5 million acres of lodgepole pine forests in northwestern Colorado over the past decade, with spruce budworms defoliating other parts of the state. In interior British Columbia, bark beetles killed millions of acres of trees.
“Once you’re in the middle of a full-scale epidemic, it quickly overwhelms your ability to respond effectively,” Everett said.
Scientists say that recent droughts and a gradual rise in average winter temperatures have contributed to the spread of mountain pine beetles and spruce budworms, which are both native insects. When trees are stressed, they’re less likely to survive insect attacks. Warmer temperatures also mean that more insects survive winter.
The technical taskforce convened by Goldmark will assess the severity of the threat in Eastern Washington and advise him on actions most likely to be effective. In many Eastern Washington forests, overcrowded trees are competing for water, sunlight and nutrients. In some areas, Everett said thinning has reduced insect and disease outbreaks. Replanting dry sites with drought-tolerant trees has also been effective, he said.
Mike Petersen, executive director of the Lands Council in Spokane, has spent several years on the Northeast Washington Forestry Council, a group of environmentalists and industry officials working to find common ground on forest health treatments for the Colville National Forest.
There’s widespread agreement that parts of the forest need to be thinned to improve tree vigor, but finding Forest Service funding to subsidize the projects is always an issue, Petersen said. Thinned trees are smaller and less valuable commercially, so the projects aren’t self-supporting. “I think the state could end up facing the same challenges,” Petersen said.
In the short term, predictions for a snowy, La Niña winter could provide a brief break in the insect cycle.
“If we get a cold winter, it tends to beat the bugs back,” Petersen said.