Prepare to see trees — probably a lot of trees — cut down on city-owned property on Mount Helena, Mount Ascension and Nob Hill in the near future.

Helena Parks Director Amy Teegarden acknowledged this week that there’s little — if anything — humans can do to halt the beetle epidemic that’s turning lodgepole and ponderosa pines into dead red sentinels across the Rocky Mountains, including on the city-owned mountainsides that provide the Queen City’s backdrop.

So she expects to focus efforts on removing dead trees, as well as those currently infested but still alive, plus other small trees crowding the city’s slopes. This effort is more of a step to prevent a wildfire from moving off the dead-tree-strewn slopes into the city than to stop the march of the bugs.

“I think the battle with the beetles has been lost,” Teegarden said. “Now the question is how to manage what the beetles have left us.

“What do we do in areas where there are no beetles now? How do we manage for more desired features on the landscape, so the forest is more fire-resistant 100 years from now, so we won’t be in the same situation?”

Jim Cancroft, a forester with Northwest Management Inc., recently finished a forest inventory and mountain pine beetle survey of about 1,400 acres of city-owned open-space lands. He found beetles on just about every acre he surveyed, with the west side of Mount Helena hit the hardest.

“Looking at everything, there are only about 16 trees per acre throughout the city’s open lands that the inventory showed were hit by beetles,” Cancroft said. “ … but on the west side of Mount Helena it was more like 30 trees per acre, and we expect a two- to threefold increase for the next year.”

He added that on Mount Ascension only about three trees per acre showed signs of beetles, but he expects that to increase exponentially.

“Remember, what we’re seeing as new dead red this year actually were killed last year,” Cancroft said.

Teegarden plans to meet with community foresters, as well as work with the Helena Open Lands Management Advisory Committee, to brainstorm on ideas and get recommendations of what opportunities are out there for dealing with the beetles.

Most of the options probably will involve removing trees, whether through commercial logging or smaller, mechanized projects. But in some places, Cancroft said, it might be necessary to remove about two-thirds of the trees to provide some kind of fire break while also creating a less bug-friendly environment.

“The focus has really changed; it’s not about prevention anymore, since we are losing he battle on the beetles,” Teegarden said. “Now, it’s more about how to mitigate what is left and prioritize areas where we can make a difference.”

Nature on overdrive

Bark beetles are an integral part of the natural environment, typically taking down weak or dying mature trees and providing natural thinning of forests. The dead trees fall down and create snags that become home to birds and are havens for squirrels and other small critters. Other times, lightning hits a dead tree, sparking a fire that burns the lodgepoles’ cones, releasing seeds that renew the forest.

Female mountain pine beetles land on a tree around August. They drill into it, then emit a chemical signal — a certain type of pheromone — that invites other beetles to the tree. The beetles lay eggs that hatch into larvae, and by the following May they’re pupae that will emerge as fully developed beetles by July.

Beetle mortality is high, yet each infested tree can produce enough beetles to take over three to five more pines. Multiply that by the number of dead trees visible today, and it’s easy to imagine just how many beetles are out there.

Frigid winters cull beetle numbers and healthy trees pitch the pests out with sap through the beetles’ own bore holes, further keeping the population in check.

But decades of fire suppression and years of drought have created tight stands of trees competing for sunlight and water. Warmer winters in recent years have also provided good beetle conditions, so the beetles are thriving.

Bettles kill trees in two ways.

First, females lay eggs in a vertical line, with the adults and offspring eating the phloem layer of inner bark in horizontal bands, cutting off the tree’s flow of nutrients. It’s called “girdling” a tree.

Meanwhile, the adults also carry a fungus on their backs that clogs the trees’ water transportation systems and tint the wood blue.

Experts say the beetles are here to stay in large numbers until the West receives sustained cold temperatures or all their food is gone. They predict the beetles will kill almost every lodgepole pine in Colorado within the next few years, where the infestation covers almost 1 million acres.

Including Idaho, Wyoming and Montana, they’re present on about 4 million acres in the West.

In British Columbia, 20 million areas are affected.

In the Helena National Forest, 34,300 acres had some type of beetle-killed trees in 2006. Helena District Ranger Duane Harp said Friday that number exploded to 400,000 acres of the 980,000-acre forest after this summer’s survey.

“That’s anywhere from a 15 to 90 percent infestation per acre of trees greater than five inches,” Harp said. “We’re estimating that in some areas, from what we saw this year, that we’ll see a four- to tenfold increase in the number of dead trees next year.”

He added that the national forest is exploring options for dealing with the dead trees.

Clearing a path

Teegarden agrees with Cancroft that the slopes of the city’s parks and open spaces are overcrowded with trees. The overcrowding provides the beetles with habitat they covet — closely spaced, stressed trees.

“Beetles communicate through their pheromones, and if you open the stand up their communication system is not as clear,” Cancroft said. “They also like dense stands because there’s less wind movement in mature trees.”

Once the beetles get into those dense stands and kill the trees, the standing dead provide prime wildfire fuel for years.

Cancroft notes that the recent survey shows there are about 850 trees per acre on city land, and of those, 80 percent are in the zero- to four-inch category. Removing those small trees and leaving about 15 feet between the larger Ponderosa pines would put about 300 trees on each acre. That means taking out about two-thirds of the ponderosa pines.

“Ponderosa pine stands typically were more open with bigger trees because you’d have ground fires run through every seven to 10 years that would whack out the small pines,” Cancroft said.

He’s already been part of projects on private land along Mount Helena’s western slope, and the city is removing trees and branches along four trails on Mount Helena and Mount Ascension, as well as in the Lime Kiln, Nob Hill and water tank areas.

The city’s projects total about 150 acres and focus on removing dead trees to create fire breaks, plus lessening the chance that they’ll fall on someone using the extensive trail system that winds through the city’s open space. The work is paid for through a federal wildfire protection grant.

Teegarden said they’re also working with the Montana Department of Natural Resources and Conservation to do additional projects to help keep wildfires from blowing off the slopes into the city of Helena.

“We’re only two years from the 100th anniversary of the 1910 fires, and it seems like those types of fires happen every 100 years,” she said. “Communities are still at risk and we need to do fuel-reduction projects.”

She was quick to add that before any large projects are undertaken they’ll come before the Helena City Commission and the public will have ample opportunity to comment.

“This will be a very public process with lots of local cooperation,” Teegarden said, adding that she doesn’t expect a much opposition to removing large numbers of trees from the city property.

“I think the backlash is if we don’t do anything, people will get upset. They’re already alarmed at the red dead, and think we need to do something.”

Reporter Eve Byron: 447-4076 or eve.byron@helenair.com