Oct. 26, 2011 - Issue #836: Winter Guide 2011

Empire of the beetle

Human error has allowed the overdevelopment of the mountain pine beetle

Anyone who has driven through central BC recently knows what mountain pine beetles can do to a forest. Huge swaths of dead trees now blanket entire mountainsides in red. British Columbia's bark beetle outbreak was unprecedented, and it didn't take long before the insects began dropping in on Alberta.

While there's a temptation to think of mountain pine beetles as a BC problem that has begun to seep into Alberta from next door, Andrew Nikiforuk makes clear in his new book, Empire of the Beetle, that nothing could be further from the truth. While bark beetles are a natural, healthy part of forest ecosystems, in recent decades outbreaks have been growing in severity and the insects have started popping up in areas where they have never been seen before. In the 1990s they wiped out more than 200 million trees in Alaska before crossing the border into the Yukon and wreaking havoc with an ecosystem that had never seen them before. In the 2000s they hit Oregon, Idaho, Wyoming, Montana, Arizona, New Mexico and Colorado. The outbreak in BC may be close to home, but it is far from an isolated incident.

Nikiforuk spent two years crisscrossing the continent in search of bark beetles and the people whose lives they've changed. While government and industry are quick to tally the economic costs of lost timber, it soon became clear that the true impact is on the psyches of ordinary people. In Alaska, a couple who built their home amongst a cathedral of towering Sitka spruce packs up and leaves, heartbroken by the loss of their trees. In central BC, school children begin colouring the lodgepole pines in their drawings red rather than green. An artist organizes a touring exhibition of work commemorating the lost forests which sees visitors leave in tears. The financial costs may be huge, but the communities that have been affected by bark beetles need far more than economic help.
 

The stories of government assistance Nikiforuk relays read like a comedy of errors. For decades, politicians and industry have been caught off guard time and again and, rather than learning from past mistakes, all too often their efforts to stop the beetles or to salvage the trees they have killed only serve to accelerate the insects' spread. Over a 10-year period, BC applied almost nine tons of arsenic and other poisons to trees in an effort to kill mountain pine beetles. The practice was ended when they discovered they were also killing off woodpeckers, one of the beetle's most effective predators. Officials have had infested forests logged during the winter in an effort to haul the beetle larvae out of an area and save the neighbouring trees, only to discover that the large stumps left below the snow line are chockfull of young. In other cases, beetle outbreaks have been noted all along the roads leading from beetle-killed timber to saw mills.

But a repeating theme throughout Empire of the Beetle highlights that  bark beetles are not a plague but a normal part of the forest ecosystem. They are simply "renewing an aging pine forest in an uncomfortable time frame for logging companies and tourists." When Alaskan ecologist Ed Berg begins investigating the malady that is wiping out the state's trees, he looks for clues in their growth rings. What he finds is that, historically, the beetles have played a critical role in the forest ecosystem. "Sure enough, Berg discovered tree rings that showed big bursts of growth after repeated beetle thinnings over 250 years. The biggest growth spurts followed beetle outbreaks roughly every 50 years." The beetles act like nature's foresters, taking out old mature trees so that those that remain can grow more vigorously.

The outbreaks of the past 30 years are a different story, though. They are vastly larger than anything seen before and have begun expanding well beyond the beetles' traditional territory. There is no simple cause for the shift in the bark beetles' behaviour, but there is a common thread. Decades of fire suppression have led to vast expanses of mature forest that do not occur under natural circumstances. Timber companies have planted monocultures that allow bark beetles to lay a landscape bare when normally they would only take the few species they find palatable, leaving the other trees untouched. The frigid winters that thinned beetle populations and thereby served as one of the forest's best defenses have been hobbled by climate change. At the same time, the warmer weather puts trees under stress, leaving them more susceptible to beetle attacks. Climate change has also allowed bark beetles to expand their range far to the north. Not only are more trees now at risk, scientists have found that forests that did not historically encounter beetles are poorly adapted to defend against them. The story is of an ecosystem out of balance.

That final point is the real kicker for Alberta. One ecologist that Nikiforuk spoke to found that beetles in the lodgepole pines of Alberta's Peace Country were producing 50 percent more young than those in southern BC. Some scientists speculate that, with a toe hold in northern Alberta, the mountain pine beetles may move into the jack pine of the Boreal and paint the country's forests red from sea to sea. Nikiforuk is quick to point out that this is far from a sure thing. "A couple of cold winters could knock those guys out," he says. But if we want to turn the tide, if we want to avoid seeing Canada become an Empire of the Beetle, we had better start learning from the past.

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