Life Cycle of Forests in Peril as Bugs Feast in Absence of Fire
TAMPICO, Wash. — This is a story about a bug, a bird and a tree.
The bug is a tiny caterpillar, the western spruce budworm, eating its way through eastern Washington forests.
The tree is the Douglas fir, the budworm’s favorite meal.
The bird is the northern spotted owl, a federally protected species that frequents the same forests the budworms are devouring.
Put them together and you get another story--a story about how hard it is to correct the damage when humans tamper with Mother Nature.
A century of misguided fire policies have upset the balance in forests in eastern Washington and throughout the West, making them vulnerable to devastating infestations. Simply zapping the bugs isn’t possible. Experts say a real solution will require a new approach to forests and fires.
“Bugs are a symptom of how the forest has changed,†Bill Boyum of the Department of Natural Resources says as his red Suburban bumps along a dusty state forest road.
He points to a sickly gray Douglas fir, bare on top and leaning hard to one side.
“What you’re looking at is death, right there.â€
Boyum, 54, the state’s southeast region manager, still wears the tan and the dusty, cracked boots of a man who has spent most of his life working outdoors.
“This is my office,†he says as he drives into the forest east of Yakima. “This is my legacy.â€
But he’s not happy with the view. The trees are green, mostly budworm-free. But they’re the wrong kind of trees, he explains, and there are too many of them.
At the turn of the 20th century this forest was about 70% ponderosa pine and 30% Douglas and grand firs. Now the order is reversed. That’s significant because budworms love firs, but they don’t eat ponderosa pines.
Blame Smokey Bear. Preventing forest fires and snuffing them quickly seemed like a good idea. But the policy wrought unintended consequences.
Ponderosa pines need fire. Before fire suppression, a ground fire burned through eastern Washington forests about once a decade. The ground fires cleared underbrush, giving pines room to grow. With their fire-resistant bark, the mature pines thrived.
Deprived of regular fires, small trees and underbrush multiplied. Douglas firs, which tolerate shade better than pines, gained an advantage and took over. The same thing happened in forests across the American West.
It’s an all-you-can-eat buffet for budworms.
“We’ve set the table with their food,†says Karen Ripley, a state entomologist.
Past budworm outbreaks lasted seven to 10 years, with 40- to 60-year breaks. But budworms in south-central Washington have been feasting for 20 years, with no signs of stopping.
Budworms infested 500,000 acres of Washington forest last year, Boyum says, and could damage 800,000 acres this year.
Although this outbreak is confined mostly to forests between Yakima and the Cascades, many western forests are vulnerable.
As Boyum follows a dirt road into a budworm-infested area, the signs are subtle at first. He points out trees with reddish tinges, trees gone strangely bald on top.
The road stops on a ridge and the damage becomes clear. Below are rivers of gray where there should be green. The trees are succumbing to budworms, which feast every spring on new growth. Healthy trees can fight off insects for several years, but these trees are giving up.
Boyum picks up a Douglas fir branch about the length of his forearm.
“Three, two, one, dead,†he says, tracing his finger along the years of budworm infestation.
The healthy needles on the lower branch give way to sparse and half-eaten needles. At the very top, a few withered, rust-colored needles are bound by a white web, the budworms’ calling card.
Budworms aren’t the only species fond of these forests. The northern spotted owl likes them too.
The deep-woods bird was classified as “threatened†under the Endangered Species Act in 1990, a move that severely curtailed logging in the Pacific Northwest.
Historically, spotted owls lived west of the Cascades. The wide-open ponderosa pine forests didn’t give them cover to hunt and hide from predators.
But as eastern forests filled with Douglas firs and underbrush, the area started appealing to owls.
Foresters are trapped. If they cut trees to thwart the bugs, they could destroy owl habitat. If they do nothing, the forests will die and the owls will suffer along with other wildlife.
“These birds are going to go extinct if we don’t provide habitat for them, but we have to realize this is a very unnatural habitat,†says Ripley. “It’s a powder keg.â€
The powder keg nearly blew during the Spruce Dome fire this August. Firefighters made their stand at Cowiche Creek, trying to keep the fire from spreading to a dense, dry forest heavily damaged by budworms.
Had the fire jumped the creek, it would not have been one of those friendly ground fires that helps pines thrive. In a forest packed with underbrush, fire easily leaps to the tops of trees, creating an uncontrollable “crown†fire. When that happens, all firefighters can do is back off and make a stand elsewhere.
Firefighters won that battle and confined the blaze. Only 2,300 acres burned. But with more trees dying each day, officials say the consequences of the budworm infestation will soon be felt beyond the forest. Boyum expects what he calls a “stand-replacement eventâ€--a fire that will burn the forest to bare ground.
“The forest is ripe for catastrophic change,†he says.
Budworms have natural enemies, but there are simply not enough birds and ants to dent their population.
Insecticide is unpopular politically, and it doesn’t work long-term. Between 1990 and 1993, federal agencies spent more than $5 million spraying infested areas. The bug population sinks for only about a year, Boyum says, but rebounds the next year just as strong.
Foresters are left with the slow, hard solution: Return the forest to its natural condition so budworms can’t thrive. That means cutting small trees and Douglas firs to let ponderosa pines regain their rightful place. It will also mean reintroducing fire.
In the southeastern region, they’re starting with 400 acres. They plan to remove the smallest trees, leaving ponderosa pines and the largest Douglas firs. It’s a new kind of logging: concentrating not on the timber they take, but on the trees they leave.
Environmental groups are often skeptical of “forest health†logging, fearing it’s a cover for cutting old-growth trees. But no one objects to the type of thinning planned by Boyum and his staff.
It won’t be easy. Logging on state trust land pays for school construction. The state has a duty to feed school trusts with logging money, and thinning forests to make them healthy is not lucrative.
“We’d take out the little junk,†Ripley explains. “The markets are very poor for little junk.â€
But for now, thinning is the foresters’ only weapon in the war against bugs.
“For that stuff over there, we’re too late,†Boyum says as he drives away from the dying trees. “We have to learn what the bug has taught us there and use it in other areas.â€
