Boulder Magazine Winter/Spring 2007-08
feature article

A Pain in the Bark

Mountain pine beetles, and the dead trees they leave behind, will shape our landscape for years to come

By Felicia Russell

Munching, crunching, breeding beetles are killing mature conifers all over the West, turning green slopes red. The bright stain spreading across mountains from Arizona to Alaska is the handiwork of mountain pine beetles. This diminutive insect has already killed millions of lodgepole pines and spruce trees on the Western Slope and is gaining ground in Boulder County.

Ever-expanding pockets of dead and dying pines surround this home near the summit of Tennessee Mountain outside Nederland, turning the mountainside yellow, red and then brown. Photo by William Ciesla, Forest Health Management International

“Right now it’s at that threshold where it could bust loose and move fast,” says Jeff Connor, natural resources specialist with Rocky Mountain National Park. Connor, who has been working on the mountain pine beetle problem in Grand Lake for five years, says the east side of the park and the surrounding lands could face a pine beetle “outbreak” like that seen on the western side of the Continental Divide.

Visitors to the park often ask Connor, “Where can I buy those red-topped trees?” Perhaps the festively colored needles remind them of plastic Christmas trees, but the ruddy look doesn’t fill many mountain homeowners or land managers with joy.

Birth of a Beetle

Mountain pine beetles are native to this part of the country and live most of their lives inside lodgepole pine, ponderosa pine or limber pine trees. The pencil-eraser-size beetle generally attacks large trees (8 to 10 inches in diameter) that are weak from drought, damage or disease. In late summer, adult beetles fly away from the tree where they developed in search of a mate and a proper nursery for their young. A beetle pair bores under the bark of its chosen tree and builds a vertical tunnel where it lays about 75 eggs.

If the beetles’ attack is successful, there will be little sign of infestation except for a bit of wood dust in the bark crevices or at the base of the tree. Meanwhile, the eggs develop into munching larvae, and fungus spreads from the adults’ bodies throughout the wood—staining it denim blue and clogging the tree’s water and nutrient transport systems. The tree slowly dies, its needles turning from green to straw yellow to rust red, and by the end of the following summer another generation of adult beetles flies away to lay their own eggs.

Mountain Pine Beetle. Photo courtesy U.S. Forest Service

Each year the U.S. Forest Service conducts an aerial survey to track insect activity and diseases. The surveyors look for yellowing or red trees to help them estimate the number of trees and acres affected by mountain pine beetles. In 2006, scientists found 1,800 affected acres in Boulder County. But without ground surveys, it’s difficult to identify trees that were attacked in the current year, because the needles don’t start to turn colors until 10 months after the initial attack.

As a rule of thumb, land managers like Chad Julian, of the Boulder County Parks and Open Space department, estimate that the brood from each infested tree will successfully attack eight to 10 new trees the following year. Scientists aren’t sure whether the growing pine beetle infestation along the Front Range is the result of the insects’ crossing the Divide or just a natural population growth. But it’s clear that the problem is spreading. “It’s not a linear graph where our numbers are going to increase the same per year,” Julian says. “Every year they’re going to start increasing more and more and more, until the population numbers get up to like they have in Grand County and Routt County and Summit County. At that point, even healthy trees can’t fend them off.”

While it may seem that mountain pine beetles are only a problem for mountain dwellers, the attacks will impact lowlanders as well. “It’s a landscape-scale event. It doesn’t just stay in the mountains,” says U.S. Forest Service entomologist Sheryl Costello. If the standing dead trees do burn near a reservoir, the resulting build-up of ash and sediment in the water will prove troublesome and costly for communities downstream. “A lot of the watersheds where people get their water in Boulder and Longmont come from these areas that are going to have big impacts from these insect epidemics and the potential fires,” Julian says.

Mountain Pine Beetle. Photo courtesy U.S. Forest Service

Switch-Hitting Bugs

In the 1970s, Boulder County faced a mountain pine beetle epidemic in ponderosa pine, which grow in Colorado between 6,000 and 8,000 feet above sea level. The current epidemic began in higher-elevation lodgepole forests (8,000 to 9,000 feet above sea level), and while traditional wisdom says that an epidemic in lodgepole pine will stay in lodgepole pine, Costello is concerned that the infestation may be jumping to ponderosa pine.

Researchers in Oregon have seen evidence of infestations switching from one species to another. “I think we’re all very concerned about ponderosa pine,” Costello says. In the autumn of 2007, Costello visited Rocky Mountain National Park to see if Colorado’s mountain pine beetles, like the Oregon insects, have jumped between tree species. To her dismay, she found the insects burrowed beneath the bark of lodgepole, ponderosa and spruce trees. While this doesn’t necessarily mean that the beetles will begin a massive attack on ponderosa pine, “it’s a little bit disheartening,” Costello says.

“They may make the jump to ponderosa pine, and if they do, they will work their way all the way down to the plains,” says Boulder County’s Julian. “That could be a catastrophe in my mind because we’re going to lose the large trees we have left down low. The only thing we can do at this point to protect the lower montane at least is to continue with forest restoration. We have a window of a few years to do so.” The beetles have also begun attacking some spruce trees along the Front Range, but Costello doesn’t think the attacks will be intense enough to kill many spruce.

“An important thing that’s led up to outbreaks in the high country is warmer temperatures and not as many cold snaps as we had 20 years ago,” Costello says. In recent years, scientists have observed beetles at higher elevations than ever before. Mountain pine beetles at high elevations that once developed from egg to adult over the course of two years are now developing in one year.

Most of the lodgepole forests in northern Colorado are 150 to 200 years old. “From an ecological standpoint, it is time for those stands to regenerate,” Costello says. Old age, drought, and competition from high-density stands make the lodgepole forests more susceptible to infestation. When a healthy tree is attacked, it secretes a sticky, resinous pitch that pushes the adult beetles out through the holes they bore in the bark. But our senior forests just aren’t strong enough to resist the beetles.

Community Efforts to Battle Beetles

Once an infestation has begun, stopping the beetles is extremely difficult, if not impossible. “We’ve been battling it all summer long and it’s not letting up,” Rob Linde, marketing director for Eldora Ski Resort, said in September. Folks at Eldora knew that they had a problem with the pine beetle, but “until we really got in there and started examining the trees, we didn’t know how bad it was,” Linde said.

This past summer, the ski resort cut 400 trees on 250 acres and preventively sprayed some “high-value” trees near the lodge and ski lifts. Linde says the effort cost “well into six figures,” but the resort doesn’t plan to stop fighting. “We have to protect the business we’re in. We have to protect the resources,” he says. “In five years’ time, if we didn’t do anything, the ski area would be a much different place.” Eldora’s new haircut isn’t all bad, however. Linde says that the Jolly Jug and Powderhorn runs have been improved by the thinning.

Ron Gosnell takes a break with Zoey and Maggie to enjoy the winter sun. A retired forester, Gosnell hopes that his Allenspark neighbors will pull together as they did in the 1970s to fend off the latest mountain pine beetle epidemic.

Allenspark residents saved many of their ponderosa trees during the 1970s outbreak by working together to deal with affected trees, and they’re trying to do it again. The Allenspark Beetle Control (ABC) began meeting in May 2007. They divided the area up into 27 units and appointed a neighborhood captain to coordinate survey, education and mitigation activities. “This is a control effort,” says Ron Gosnell, a retired state forester and former ABC coordinator. “We’re trying to keep the number of new beetle hits at a manageable level.” ABC is teaching residents how to identify and remove affected trees. Gosnell saw firsthand how community efforts could effectively minimize damage from pine beetles when he worked with the Allenspark community as a forester in the ’70s. “Allenspark went the extra mile because not only did they kill beetles and control beetles, but they introduced forestry,” he says. While he says that this infestation is in many ways different from the one 30 years ago, he hopes that community cooperation will be just as effective.

A Fight on Many Fronts

It may be possible to save some mature trees near campgrounds, in parks and on private property, but most trees will be left to their own devices, says Connor with Rocky Mountain National Park. Preventively spraying trees is too expensive to do on a large scale. It costs $10 to $20 per tree per year to coat the lower trunk with a low concentration of pesticide that repels the beetles, which can be quite costly over a 10-year outbreak, Costello adds. Scientists and foresters agree that fire and extreme cold (minus 34 degrees Fahrenheit for a week in winter) are about the only things that will stop the pine beetle infestation in lodgepole pine.

Although neither is likely to occur, fire or bitter cold would benefit several tree species throughout the state that are currently facing rising insect and fungal diseases. “We have other epidemics happening right now that aren’t getting the publicity,” Julian says. “Here, shortly, we could have insect activity in every one of our conifer species, and that non-native disease [white pine blister rust] in our limber pine.” Concurrent epidemics are rare, Julian says, but they could happen more frequently as temperatures continue to rise. Scientists aren’t sure what to expect.

Additionally, the mountain pine beetle epidemic is larger and more widespread than any other outbreak in the past 150 years. “We’re seeing West-wide beetle outbreaks that we’ve never seen before,” Costello says. Yet outbreaks this large may be within the range of natural variability, even if they haven’t been observed since white settlers moved into the area.

In Boulder County, whole mountainsides of beetle-killed trees could come to resemble those in Grand, Routt and Summit counties. But, however ugly the forest may look at first, there are numerous benefits. Aspens, birds, hoofed animals, wildflowers and grasses will flourish amid the woody skeletons; and young lodgepole pines that survive unscathed will begin to replace the older stands, says Julian.

To prevent large bark beetle outbreaks in the future, forest management plans need to include thinning and prescribed burning regimes to create more age and species diversity as well as a mosaic of conifers, deciduous trees and open spaces that better resemble the historic forests, Julian says. “We have to work together because beetles don’t follow political boundaries.” |

Blue Wood

Photo courtesy Jerry Naro The mountain pine beetle and its fungal friend leave behind trees that many consider trash and a few consider treasure. Jerry Naro has been working with beetle-killed wood for more than 25 years. “What originally brought me into it was just the beauty of it,” he says. “It’s something that I enjoy working with. I’m constantly amazed at the colors.” Naro is a master woodworker and owner of Whispering Winds Design in Nederland. He builds furniture, doors, cabinetry and paneling with this beautiful blue-streaked wood. “The blue has always been a sign of lesser-quality wood, but that’s not the case. It’s just as structurally sound,” he says. The problem with harvesting the wood is that it’s dead when lumberjacks cut it down and may have been out so long that most of the wood is unusable. Naro says that the trees must be cut within eight to 10 months of dying to preserve the wood’s integrity. Most lumber mills that harvest the beetle-killed wood chip it for animal bedding and particleboard or cut it for dimensional lumber. Naro says it’s difficult to find mills willing to cut the blue wood in dimensions and grades that artisans can use. “I don’t think you’re going to get someone to come in and invest a huge amount of money to clean up this epidemic,” he says. As much as he likes working with the wood, Naro says that the market for beetle-killed wood is small, and he doesn’t see an abundance of blue wood making it any more valuable or desirable in a market driven by scarcity. However, for someone with the right marketing angle, the pine beetle epidemic could be a good opportunity to use and sell a “green” product. —F.R.

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