TREAT THE BEETLES
Strategy Offers Hope in Beetle Battle
Small battles with beetles can be won, a Forest Service report says.By David Frey, 3-15-10
Courtesy For the Forest
Combating the spread of mountain pine beetles as they destroy trees across the West may be impossible to do on a large scale. But on a small scale? It may be feasible, and an experiment on the slopes of Smuggler Mountain above Aspen, Colo., could be the proof.
A report on the efforts found the twin strategy – removing the trees that were infected and treating the trees that weren’t – succeeded in reducing the damage caused by the beetles.
“We were all kind of wowed” by the success, says Nancy Gillette, a Forest Service insect scientist based in Berkeley, Calif.
The operation conducted on Smuggler Mountain could have applications across the West, where an unprecedented beetle outbreak has wiped out millions of acres of ponderosa and lodgepole pines from Canada to Mexico.
Similar efforts may be difficult on large scales, where costs and controversies over logging roads and other forest issues could raise bigger concerns, Gillette says, but the method could be a way to protect isolated areas, like those around towns or ski resorts, in an effort to protect views and lessen fire danger.
“I can see this easily being done over hundreds of acres,” Gillette says. “Once we get to thousands of acres, I think it becomes questionable.”
The mountains around Aspen are only the latest area to be beset by the plague of mountain pine beetles, which have ravaged trees weakened by drought across the West. The beetles bore into the bark to lay their eggs, killing the trees while the newly-hatched insects spread the plague onward, leaving a swath of brown trees across the region.
Spurred on by the nonprofit group For the Forest, Aspen and Pitkin County spent $110,000 on a project to treat 250 acres of lodgepole pines on Smuggler Mountain, a popular backyard playground for Aspen hikers. Crews used helicopters to remove so-called “brood trees” that had already been infected with the destructive beetle. The trees that hadn’t yet been infected were treated with the chemical verbenone. A biodegradable pheromone that the beetles themselves produce, verbenone sends a sort of “no vacancy” message to other beetles and encourages them to seek another tree.
Gillette’s study found removing the brood trees “effectively lowers attack rates.” Areas where the trees weren’t removed showed a 40-fold increase in infested trees.
The study also found the risk of beetle attacks “was significantly lower” in stands that were treated with verbenone, and that the chemical seemed to be slightly more effective when applied as flakes rather than in pouches.
Verbenone “significantly reduced the probability of lodgepole pine trees being attacked by mountain pine beetle,” the report says.
“We’re excited by these results,” says For the Forest Executive Director John Bennett, a former Aspen mayor, “because they show that ways exist to protect our forests and improve public safety in the wildland/urban interface … especially in valuable recreational areas around communities.”
For the Forest had pressed for the work to try to control the beetles in an effort to reduce the danger to hikers and the impact on the aesthetics of Aspen’s backdrop.
“The success of the beetle-control effort on Smuggler Mountain shows that if we work together we can avoid closure of popular trails used for hiking, mountain biking and other activities. And this approach could potentially protect ski areas,” Bennett says.
The study also found that denser stands show greater infestations than less-dense stands.
Gillette, an entomologist with the Forest Service’s Pacific Southwest Research Station in Berkeley, Calif., has led experiments using verbenone in California, Idaho, Washington and Wyoming.
Forest experts believe that although the spread of the beetle was slower last summer due to cooler temperatures, the insects will likely kill at least 80 percent of mature lodgepoles in Colorado before the epidemic subsides.
More than 6.4 million acres across the West have been affected by the beetles already. That number will probably only increase, Gillette says, unless the warming planet does a reversal.
“It’s largely climate driven,” she says. “We expect the climate to warm. We expect more periodic droughts. So we expect the outbreak to be sustained. … I’m not very optimistic.”
David Frey writes in Glenwood Springs, Colo. Read him on his Web site, www.davidfrey.me or on Twitter.
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Too many big fires and not enough small fires. But smoke is the human complaint that drives urban forestry on rural lands. Without smoke, you can't have old growth, and you can't have P Pine stands, and you can't have prairies and brakes and all the non-conifer stuff that creates diversity. Stand replacement fire produces another stand. Frequent fire keeps conifers from being there. Since Native Americans managed the landscape for thousands of years, perhaps it is time to have them do it once again. That would be culturally correct, and probably a source of institutional hand wringing. So we would just have to live with it. Or quitchyabitichin'.