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Spruce beetles are coming in Vallecito

Preventing damage seen in the Wolf Creek area is a priority

The bark beetles are here.

Actually, the bark beetles that kill mountain trees are always around, San Juan National Forest representatives told a small group of Vallecito residents Tuesday evening. They answered questions and discussed options to make devastating infestations such as those on Wolf Creek Pass less likely in our forests.

The assumption of Tuesday’s meeting was that tree stands around Vallecito will be affected.

“At this point, it’s not immediately evident in many of the view sheds, but Wolf Creek Pass is the future,” Columbine District Ranger Matt Janowiak said.

Janowiak showed maps of the San Juan National Forest that already have beetle infestations and areas at risk of infestation. Those are dense, high-elevation stands of large, mature Englemann spruce, especially when there is little diversity of species or age of trees.

There is a beetle-killed stand of Englemann spruce at the top of Middle Mountain Road in the Runlett Park area, said Gretchen Fitzgerald, a San Juan National Forest reforestation specialist.

Forest Supervisor Kara Chadwick came here 15 months ago to take over the supervisor position.

“My first introduction was all the dead trees coming over Wolf Creek Pass,” she said. “We really need to address this situation. ... We won’t stop the beetles, but we can create resiliency, sell timber and use funds for reforestation.”

Pretty much every mountain-tree species has a beetle to attack it – spruce, fir, Ponderosa pines. And then there’s armillaria, a disease that attacks tree roots, as well as spruce bud worm that eats the growing tips.

So, are we facing a treeless future in the San Juan National Forest?

Not necessarily.

Beetles are drawn to trees that are stressed by drought or overcrowding. So thinning is one way to make at-risk stands more resilient. Trees in good condition can sometimes push out beetles that try to bore in, before the beetles settle in under the bark and lay eggs.

Fitzgerald said, “If a tree is infected, you can water it, and it might sap the beetles out. They aren’t necessarily doomed.”

But the tree might have other issues such as armillaria that weakened it and made it attractive to beetles.

It’s the beetle larvae that do the damage, Travis Bruch said. They tunnel around the tree trunk as they feed, girdling the tree. They also carry fungus. The beetles survive winter in the doomed trees and emerge the next year to look for new hosts.

Fitzgerald said beetles send out pheromones that attract even more beetles. The cycle can be disrupted by a winter cold enough to kill beetles under the bark of their large hosts or by a wet summer. The beetles don’t go into tree trunks less than 4-inch diameter, “so we think the beetles are pretty much done on Wolf Creek,” she said.

There is still green under-story there for regeneration.

“It’s where there’s no under-story that’s a concern,” she said.



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