How the west is coping with the most severe disaster to hit our forests this century.
By Gary Lantz

Devastation from the mountain pine beetle covers these mountains in Dillon, Colorado. (Credit: Whit Bronaugh)

The scene from a helicopter flying over miles of unbroken British Columbia forest revealed a sea of rusty red, as if millions of trees were preparing for autumn dormancy. In a way the vista was morbidly colorful, but it was strangely ominous for evergreen woodland in Canada, where red pine needles have become a harbinger of environmental disaster, rather than some routine sign of seasonal change.

“If it’s red it’s dead,” the pilot pointed out. From his airborne vantage point, the devastation extended to the horizon in every direction. The carnage was the result of a mountain pine beetle outbreak, killing millions of trees from Alberta and British Columbia to the southern Rockies in the US. Potential repercussions range from catastrophic fires, to the closing of popular recreational sites, to the economic impacts of ailing tourism and loss of jobs.

It is, as Montana forest entomologist Ken Gibson points out, the “perfect storm” of insect attacks. How and when it will end, and what foresters learn from the epidemic, are still in question. However, few doubt that the scope and severity of this outbreak rank among the worst in recorded history; a blow to our forests that could rewrite the way North America manages its timber resources for centuries to come.

While foresters scramble to mitigate as much damage as possible, most acknowledge that they don’t have a blueprint in place to deal with an assault of such magnitude. They admit that the insects are attacking an aging forest, one that’s overgrown due to fire suppression and lack of thinning; a forest made even more susceptible by varying weather patterns, including drought and warm winters.

The combination of weakened trees and less than optimum weather conditions has presented the mountain pine beetle with a rich smorgasbord. Someday maybe someone will find a parable in how an insect smaller than a fingernail can lay to waste millions of acres of forestland. But no matter the lessons to be learned, the outbreak remains a bitter pill to swallow as vast tracts of pines are reduced to rubble, each red needle representing a huge loss for communities attuned to a profitable and aesthetically pleasing woodland environment.

British Columbia and Alberta currently estimate that more than 33 million acres of lodgepole pine forest have been decimated. The New York Times reported that by midsummer 2009 at least a million acres of pines had been killed in Montana alone, and that statistics anticipated from Wyoming and Colorado most likely would be worse.

At the same time, foresters were predicting that in time all of Colorado’s lodgepoles greater than five inches in diameter would be lost to beetle attacks. Some were adding that the outbreak could spread as far east as the Great Lakes. Additional reports pointed out that the infestation was spreading into Ponderosa pine forests of the Rocky Mountains’ Front Range, a much more densely inhabited region where homeowners could face the threat of wildfire fueled by the accumulation of downed and dead wood.

A beetle crawls through the mazelike gallery that it has carved out of a tree. (Credit: Whitney Cranshaw, CSU,

Experts also warned that the outbreak might not subside until the insects have literally eaten themselves out of house and home, or when winter temperatures in the mountains once again achieve a prolonged minus 30-40 degrees below zero; readings that haven’t been seen in decades. It takes periods of extreme cold to nip back overwintering beetles. Unfortunately, a warming climate has resulted in just the opposite, allowing for a longer growing and breeding season.

The culprit is a black, hard-shelled beetle of the Dendroctonus family. The insect’s Latin name means “tree killer,” and if conditions are right, it lives up to its name in an impressive manner. Under average conditions, explosive infestations by this native insect are kept in check by natural factors that promote overall forest health, including adequate rainfall and nutrients, mixed age stands, insect-killing cold winters, and natural thinning processes, including periodic burning. Healthy trees growing in a healthy environment have the defenses to fight back. Aging, overcrowded, unhealthy forests don’t stand a chance, as foresters and landowners are seeing firsthand.

Dendroctonus beetles select trees ripe for infestation, drill through the bark, dig a gallery in the cambium layer, and lay eggs. Hatched larvae feed upon the nutritious cambium and deposit a fungus that inhibits sap flow. In the words of a Canadian forester, the tree simply dies a slow death of thirst.

The fungus stains the wood of the infected tree blue, rendering it unsuitable for some salvage applications. Fungal spores are free for the taking from the atmosphere, and beetles also seek to overwhelm their host’s defenses by emitting pheromones, or scent messages, that summon a swarm of beetles eager to lay eggs in a suitable host. The tree fights back by attempting to block the galleries with a pale resin that looks somewhat like candle wax, seeking to trap the insects in a rapidly constructed tomb.

The cross section of timber clearly shows the blue stain trademark of the mountain pine beetle. (Credit: Laird Robinson, USDA Forest Service,

Young trees growing in a stable environment are capable of surviving beetle infestations as severe as the current one, foresters say. Sadly, there’s little hope for poorly managed, aging stands of trees already weakened by a lengthy drought. Human assistance comes in the form of aggregator pheromone packets that attempt to fool the beetles into believing a particular pine is already fully infested. Spraying can deter the beetle onslaught, but the application must extend upward to a point where the tree is only some four inches in diameter. Spraying is an expensive process that’s difficult to administer over an area as vast as the one now under siege. Mechanical clearing is another weapon that works to stifle the insect advance, but most foresters say it’s imperative to remove at least 75 percent of a stand in order to protect the remaining 25 percent.

Therefore the majority of treatment has been reserved to protect watersheds, create strategic firebreaks, or protect popular recreational areas. On the private front, homeowners face the prospect of removing dead trees and replanting. One Colorado man reported he’d been forced to remove more than 400 trees from his five-acre homesite since 2006.

The scope of the disaster is difficult to envision. The impact becomes clearer when forestry officials in British Columbia report that they’re facing salvage operations in stands of dead trees that could fill 13 million logging trucks. Cities from Canada to Colorado face tree-removal projects that will cost hundreds of thousands of dollars. Highway crews may be hard-pressed in some places to remove trees that have fallen across roadside rights-of-way, or that threaten utility lines. Ski resorts face ongoing efforts to keep slopes clear and mitigate their losses through replanting. And campsites, recreation areas, and trails have been closed due to the dangers of deadfall.

Estimates indicate that dead trees could be falling to the ground for another 15 years or so. The resulting biomass is difficult to imagine . . . and equally difficult to render into profitable products.

Sawmill operators say that the quality of beetle-killed logs is often impaired, and that salvage requires some retooling. And even if the logs were in perfect condition, the number of mills currently in operation isn’t adequate to handle the magnitude of salvageable timber. Time constraints limit the installation of additional sawmills, since experts believe that the logs will deteriorate beyond the point of being salvageable in just a few years.

Some of the wood has been processed into firewood pellets, and some speculators believe that the vast amount of biomass could be converted into energy much like coal. Engineers at paper mills have experimented with processes to remove the blue fungus stain that remains after infestation. Timber for log homes is another possibility for salvage efforts. Still, the sheer amount of biomass tends to overwhelm any plans currently in place for salvage operations.

Beetle-killed trees in Medicine Bow National Forest are being removed as part of an active fuel reduction project. (Credit: Dan Smith)

While foresters consider the continental implications of the outbreak, woodlot owners listen to the sounds of beetles turning their dreams into sawdust. As one woman told her local newspaper, the family’s small woodlot had been a gift from one generation to the next, and an integral part of their future. In fact, the trees themselves were almost like a part of the family. Then she stepped outside one morning and heard the strange noises. “I saw the sawdust drifting down, and I knew I was hearing the beetles attacking our trees—I was hearing them perish. It was like old friends were dying.”

As public officials scramble to seek help at the federal level to clean up the dead and dying trees and prevent the catastrophic fire outbreaks that could occur if they don’t, scientists are implementing studies to ascertain how the removal of millions of trees will affect air quality and regional weather patterns, including rainfall. Few doubt that the predicted wildfire outbreaks will have an effect on air quality. As Andy Norman, a fuels specialist with the Forest Service points out, “It’s all going to burn eventually.” At the same time, forest fire experts confess they’re uncertain about fire behavior following mountain pine beetle epidemics of such magnitude, and can only guess at how to plan for any upcoming conflagration.

Rick Cables, director of the Rocky Mountain region for the US Forest Service, told the Denver Post that while the current epidemic may be too severe to contain, goals in the future must focus on creating forests that are more resilient, and able to thrive under the vagaries of climate change and evolving human pressure. Above all, he said, foresters must establish a diversity of age classes, so that a single insect or pathogen cannot destroy an entire forest at once.

Cables added that in Colorado, forests are mostly old and ready to regenerate. He said that if you look at all the species—aspen, spruce, lodgepole pine—they all have one thing in common: old age. Uniform aging presents another problem. Ingrid Aguaya, Colorado forest entomologist, points out that pine beetles migrate to less-favored hosts when the readily available stands of mature lodgepole pine (eight inches or more in diameter) are exhausted.

Infestation then spreads to ponderosa, limber, bristlecone, and white pines. In the past, pine species growing at higher elevations generally could count on the saving grace of hard winters to deter beetle attacks. However, in recent years winter temperatures simply haven’t come to the rescue.

Cathey Hardin, forester in the Caribou-Targhee National Forest in southeast Idaho and abutting the Montana, Wyoming, and Utah borders, says the beetles are overwintering in high-altitude whitebark pine stands where temperature extremes had deterred it in the past. The high survival rates are largely responsible for the current epidemic status.

The assault on whitebark pine, a critical food source for grizzly bears, demonstrates how the outbreak affects not only economics and aesthetics, but imperiled wildlife populations as well. Hardin and fellow scientists are currently attempting to document the pine beetle migration to whitebarks while seeking to protect high-value trees, especially those with resistance to blister rust, which in turn should have the more robust health needed to combat beetle epidemics. These will prove invaluable as seed trees during restoration efforts. The beetle outbreak has been so significant, Hardin said, that the insects have attacked trees six inches in diameter or less, two inches smaller than those they generally prefer.

Frank Carroll of the Black Hills National Forest, a 38-year veteran of the Forest Service, tends to take a more philosophical approach to the beetle outbreak, one that combines history and a more holistic approach to long-term forest management.

Carroll says that the massive beetle epidemics are nothing new. It’s just that our forests haven’t been managed to survive them. “The Black Hills are a prolific pine-growing forest,” Carroll said. “But a healthy forest is like a rose garden. It needs to be cared for and pruned, and the number of trees pared back to provide adequate nutrition.”

The red trees in the closely-packed forest on the right are all dead stands in South Dakota’s Black Hills National Forest. The recently thinned forest on the left has managed to deflect beetle infestation so far. (Credit: Frank Carroll)

Carroll points out that the healthiest stands of pine in the Black Hills contain 60 to 100 trees per acre, rather than the 3,000 or more found in beetle-ravaged stands. “Roosevelt and The Civilian Conservation Corps had it right,” he emphasizes, pointing to a picture of Corps workers thinning trees in the 1930s. He adds that forest management practices were in place well before 1492, when Indians relied upon 77 documented purposes for prescribed burns.

“Pine beetles will be with us forever,” Carroll said. “It’s up to us to at least do as much as the Indians did to maintain forests and plant communities that in turn provide the resiliency and good health.”

When Rick Cables addressed a congressional subcommittee on forests and forest health, he pointed out that when General George Custer explored the Black Hills in 1874, he described a mosaic of vegetation: open, parklike stands of Ponderosa pine and scattered patches of “dog-hair” thickets interspersed with meadows. “The forest Custer saw was created and maintained by frequent wildfire,” Cables said. “The Black Hills are a fire-adapted ecosystem, and ponderosa pines depend upon periodic fire for their overall health. Primarily due to our fire-suppression efforts, these open stands evolved into the overcrowded and unsustainable situation we see today.”

Cables added that there are four times more trees alive in the Black Hills today than in 1897, creating hazardous fuel conditions, and allowing for the weakening effects of drought that increase susceptibility to insect infestation. He added that as a result, pine beetles threaten lodgepole and ponderosa forests in Colorado, South Dakota, and Wyoming, and Douglas fir beetles threaten fir stands in Wyoming, while the danger of catastrophic forest fire looms.

Carroll concluded his testimony by saying that some 250,000 acres of Black Hills National Forests have been treated since 1997 by various methods including timber sales, thinning, and the removal of hazardous vegetation. He said these treatments, implemented to reduce wildfire fuel loads and improve overall forest health to combat insect infestation, will continue as aggressively as the law, policy, and funding allow.

Sadly, aggressive forest management may be too little too late to combat the ongoing pine beetle eruption. It is hoped that the scale of the devastation may be enough to promote better understanding of the long-term needs of forest health; create more viable working partnerships between city, state, and federal entities; and prompt Congress to provide funding for the emergency measures that will be required to treat the continuing beetle eruption, conduct large-scale salvage operations, and prepare for the inevitable forest fires.

By the end of July, Montana Senator John Tester had moved in that direction by proposing the Forest Jobs and Recreation Act, a bill he said would create additional timber jobs by requiring the Forest Service to manage a certain number of acres each year for timber harvest. Tester said the act would focus on areas infected by pine beetles that pose a serious wildlife threat to Montana communities and their drinking-water sources. The senator added that the bill also requires the Forest Service to put people to work on projects that protect watersheds and improve big-game habitat.

Certainly similar legislation will follow in the aftermath of the beetle outbreak, but as Frank Carroll points out, forest management plans may last only as long as a two-term president, or a change in political philosophy. Forest managers come and go in increments measured at best in decades, while forests may not mature for a hundred years.

So it seems that long-term forest health requires an unabridged ethic, a vision strong enough to survive party politics, vacillating economics, uncertain weather trends, and the constantly shifting patterns of human perception. Otherwise America’s forest resources will pay the price of land health measured in the length of time it takes to write policy or draft legislation. And that price, as we’ve seen during the ongoing devastation now ravaging millions of acres of timber, can literally stagger the imagination. It is one we can never again afford to pay.

Gary Lantz writes on environmental topics from Norman, Oklahoma.


This article was published in the Autumn 2009 issue of American Forests magazine.