You may have heard by now about a beetle invasion that is laying waste
to the vast pine forests in interior British Columbia. Lumber mills up there have moved to triple shifts to process salvaged timber.
The same bark beetle that's taking advantage of warmer climes up north is chomping its way through pockets of Northwest forests. Montana and North Idaho are weathering the worst attack in 20 years of mountain pine beetles and a cousin, the Western pine beetle. But the end of the drought and some new tricks courtesy of science may give our trees a fighting chance. Correspondent Tom Banse reports from north central Washington.
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(Sound of walking through a forest.)
Forest entomologist Connie Mehmel is nosing around a dense grove of
pines mixed with a few firs. (Sound of a hatchet chop.) She pulls out a small hatchet when she spots a telltale sign of beetle attack: a gusher of pinesap.
Mehmel: "Aha! Ah. Oh, this is so cool."
(Sound of chopping.)
Bark beetles attack and kill pines, especially ones weakened by drought or
crowded in forests untouched by fire. The tree's only defense is to push
back with sap.
Mehmel: "This is big old pocket of pitch. What has happened is the tree has
filled up that gallery with pitch. So that beetle is not successful. That
beetle has been killed by the tree.
Tom Banse: "That's what you like to see happen?"
Mehmel: "Yeah."
A nearby pine here in Lake Wenatchee State Park is not so lucky. Woodpeckers have chipped away its bark to reveal a spaghetti tangle of beetle burrows that girdle the now dead tree. When one dead tree multiplies into thirty or hundreds, the forest becomes vulnerable to wildfire and its scenic and commercial value sinks.
Here on the east slopes of the Cascades, a logging crew has been called in to intervene.
(Sound of logging machinery.)
The highly mechanized crew has orders to space out the trees in the park and remove some of the brush underneath.
Logger Scott Warman of Peshastin expects the proactive thinning will help the remaining trees resist a larger outbreak.
Scott Warman: "Once you thin it out, it gives the trees that are left more sun, water, more nutrients. They grow better. They're just healthier trees and they're less susceptible to bark beetles."
Thinning can serve multiple purposes. The technique to fight the native beetles also reduces the risk of severe wildfire. The Lake Wenatchee beetle offensive was paid for with wildfire protection money.
The Forest Service's Connie Mehmel says the above average rainfall of the past fall and winter should also help trees be stronger.
Connie Mehmel: "We had very drought-y weather last and that was a very good year for bark beetles. Now this year -- knock on wood -- we're out of the drought now."
Separately, Northwest researchers are working on a chemical trick to repel the destructive beetles. Washington State University professor Brian Lamb leads a team trying to fool the tree killers with their own scent signal, called a pheromone.
Lamb: "It's pretty interesting, in fact. You get little filaments of gas traveling through the canopy and it wafts back and forth and the insects respond to these little filaments as they go by."
Scientists have artificially duplicated the scent that says "this tree is taken - the deli's closed." You can buy it. The unsolved challenge Lamb's working on is how to disperse the scent around a forest cost effectively.
In the meantime, the native pine beetles are reaching epidemic levels in the inland Northwest. The economic loss is hard to pin down. All foresters can do for now is thin, and counsel, and monitor like Connie Mehmel does. She throws herself completely into the task.
Connie Mehmel: "Here I have found a larvae. try to get it out of here without smashing it."
(Sound of chopping and scratching.)
Tom Banse: "That's a rather unattractive thing."
Connie Mehmel: "Oh, you don't like it?"
Tom Banse: "I don't like."
Connie Mehmel: "I think it's cute."
And right then she SWALLOWS the tiny white larvae. I'm not hungry, thanks.Oregon Public Broadcasting
