Pinons beware: The beetles have landed
GSPI News Editor
A beetle no bigger than a grain of rice is threatening to do a Paul-Bunyan-size job on area pinon pines.
Aided by drought, the pinon bark beetle is killing off an increasing number of pinon trees in lower-elevation terrain in Garfield County.
Pinon and juniper trees make up so-called P-J forests. Although P-J forests aren’t in danger of losing their “P” altogether, the beetle is expected to spread through these desert woodlands.
The pinon bark beetle has done significant damage in southwestern Colorado, where extreme drought made trees susceptible to the beetle. Outbreaks are being seen now locally.
“We’re seeing little pockets of it that are just spreading,” said Kelly Rogers, assistant district forester at the Colorado State Forest Service Grand Junction office.
The outbreaks are starting to occur in Garfield County, almost anywhere pinon trees are found, he said.
The pinon bark beetle is one of 11 species of ips beetles, sometimes known as engraver beetles, in Colorado. They attack pines and spruce.
Usually, the pinon bark beetle doesn’t pose much of a threat, simply targeting the weakest trees.
“It is a natural thinning process, in a way,” said Rogers.
But the drought of the last several years has weakened trees enough to allow a more widespread infestation.
In Durango, Mancos and Dolores, “entire hillsides are being heavily killed off,” Rogers said.
Still, Rogers isn’t worried about the beetles wiping out pinon populations altogether, and the damage they cause is all a matter of perspective.
“It’s not going to look like a fire went through it,” he said.
Yet recovery can take a while.
“It’s a pretty slow process any time you disturb a pinon-juniper woodland,” Rogers said. “You’re probably talking hundreds of years before it’s reforested again.”
Both pinons and junipers have heavy seeds that aren’t distributed by wind, slowing down reforestation, he said.
What’s to be done?
“It’s pretty hard to do anything on a landscape scale where you’ve got a whole hillside starting to turn brown and fade,” Rogers said.
Access can be difficult, and the limited uses for pinon wood restrict opportunities for commercial-scale operations.
“You’re having to pay to haul it off,” Rogers said.
Most of the attention focuses on residential areas.
Homeowners wishing to save pinons should remove infested trees, chemically treat lives ones, and thin forests to reduce the risk of infestation, experts say.
Infested trees show telltale signs, such as browning needles and beetle bore holes. It’s best to cut them down while the beetles are still in them, and dispose of the wood by burning it in a pile, covering it with plastic and letting the heat buildup kill the bugs, burying it, chipping, or hauling it to a compost site that will accept it.
Jim Duke, owner of the Caca Loco compost operation at the city of Glenwood Springs’ South Canyon Landfill, said he’s had to turn away people who have asked if he would accept their beetle-killed wood.
The problem is that the wood could sit for months before being composted, allowing time for beetles to infest trees around the landfill.
He said he will accept ground-up wood with beetles in it free of charge, but people should let him know it’s contaminated so he can immediately mix it into his sludge.
As with composters, homeowners should avoid stacking infested wood near healthy trees, as the beetles will spread.
Insecticides containing permethrin or carbaryl (one goes by the retail name of Sevin) are used to treat trunks and larger branches. Because the beetles produce about three generations per year, treatments must be applied a couple of times over the season.
To be effective, the pesticides must be applied before infestation happens.
Thinning forests can prevent, or expedite, beetle spread
Rogers said there’s no practical alternative to insecticide use for protecting individual trees. However, a good long-term approach is to thin out a woodlands so only healthy pinons that are least susceptible to infestation remain.
“The more thinning you can do and the more water you can give those trees, the better, and the more resistant, they’ll be,” he said.
But there’s only one problem with thinning – and it’s not a minor one. The sap flow from the thinning work attracts more beetles.
“It’s kind of a double-edged sword. … Long-term that’s the best preventive measure you can take, but if you’ve got a lot of bugs in the area, you actually can be pulling them into the yard by doing that,” Rogers said.
In fact, the thinning that residents have been doing to protect their homes from wildfires during the drought has been another factor in the beetles’ spread.
Thinning near infested areas probably should wait until winter, when the bugs aren’t active, Rogers said.
A part of nature
He called the current outbreak “one of those things that’s probably bound to happen eventually. Either you can manage the forest to suit your needs, or let nature do it by fire and disease.”
The pinon bark beetle is a native species, he noted.
“It’s not something that’s been imported. These bugs have evolved with the trees and they’re a part of the ecology out there.”
While the natural thinning the beetles make happen might be for the best in the long run, it can create a short-term increase in fire hazard. P-J forests are already highly flammable, even when green.
“When it’s dead wood it’s just as flammable, if not more,” said Rogers.
The Colorado State Forest Service will cover up to half the costs for thinning forests for fire reduction purposes.
It also will provide a free initial consultation regarding sick trees, such as those infested by beetles, and then charge based on a service agreement for follow-up treatment.
For more information, contact Kelly Rogers or John Denison at 1-970-248-7325.
Contact Dennis Webb: 945-8515, ext. 516
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