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A logger's worst nightmare BY JAMES HRYNYSHYN
A news feature for Sympatico-Lycos The tiny mountain pine beetle threatens western Canadian forestry industry If the road to hell is paved with good intentions, then the managers of North America's forests are in a lot of trouble. For decades they fought forest fires with an almost missionary zeal, believing they were doing right, not just by the people whose lives and livelihoods were threatened by the flames, but also by the trees. The tiny mountain pine beetle has proved them wrong. Very, very, wrong. Hundreds of thousands of hectares of forests in Canada, and more in the United States, are infested with the beetle. Forestry companies are losing hundreds of millions of dollars worth of their raw material. And some scientists suspect we haven't seen the worst of it yet. Known to entomologists as Dendroctonus ponderosa, the pest is native to western Canadian forests, boring into and eventually killing several species of pine trees, primarily the lodgepole pine. The current infestation is not a new problem - more than 500 million trees have been lost to the mountain pine beetle this century in British Columbia alone - but it is threatening to be the worst on record. And according to forestry officials from the Pacific to the Black Hills of the Dakotas, it's all because we fought too many forest fires.
Nothing new in the woods "But 50 years ago, we started protecting our forests," he says. That's when the troubles began. Mountain pine beetles lauch their assault by boring into a tree's bark, carrying with them spores of the bluestain fungi. Eggs are laid in the tree and together the beetle larvae and fungi cripple the tree's ability to transport water up its trunk. Infected trees turn a characteristic red color and eventually die. Over the millennia, lodgepole pines and other victims of the beetle have evolved defences, of course. Bark resin of healthy trees can prevent infestation by destroying the beetle's eggs. But older trees don't produce as much resin, making mature stands of pines vulnerable to attack. Back when wildfires were allowed to burn, most forests were composed of a variety of ages of trees. "You would not have large, contiguous stands of mature trees," says Safranyik. Such forests could easily withstand pine beetle attacks. Beginning in the 1950s, however, forest fires were fought aggressively. As a result, mature stands survived to the point where they were easy targets for the beetles. The worst hit were lodgepole pines, until recently considered of little value by the industry and left unlogged.
A common enemy Henry Burkwhat, a forest health specialist with the state's Department of Agriculture, agrees that letting more wildfires burn would go a long way toward controlling the beetles. Unfortunately, that's no longer an option, thank to urban development. "We can't let the fires burn wild, because they're such a threat to human populations," he says. This dilemma means more than just lots jobs in the forestry sector, though. Burkwhat says the failure to let fires run their course has imperiled dozens of other species that depend on a "mosaic" of stages of forest development. In Oregon, for example, lynx, eagles and the famous northern spotted owl are losing precious habitat. What little remains after the clearcutting operations are often mature stands with trees of similar age. In British Columbia, forestry managers are still trying to get a grip on how bad the latest infestation really is. Peter Hall, a forest entomologist with the provincial Ministry of Forests, says a lack of funding in recent years has hampered attempts to estimate the ecological or economic scope of the problem.
Billion-dollar problem Although some government estimates are as high as $1 billion worth of timber, Hall says its too early to give precise figures. "The potential impact is high. What the actual cost is, we don't have the numbers. It's not straightforward." Sometimes logging companies are able to switch the cutting operations to focus on areas where mountain pine beetles are in the early stages of infestation. The wood can be saved if the process is not too far advanced. Moving equipment and camps isn't cheap, but leaving an infected stand for too long can render it worthless. Safranyik, Hall and other scientists are trying to develop methods of controlling outbreaks. Much attention has focused on baiting beetle traps with synthetic pheromones, chemicals that mimic natural compounds used by the beetles to attract mates. With a mild infestation of say, 2000 beetles, such strategies might work. If researchers can manage to kill 99 of every 100, that might be enough to prevent the beetles from spreading from one tree to another. The reality, however, is that typical outbreaks can involve a 100 million beetles. Even at 99 per cent mortality, says Safranyik, that still leaves a million behind - enough to infect hundreds or even thousands of pines. In the end, the only alternative left to managers is burning the infected stands.
The bigger picture Pine beetles don't deal well with cold, wet conditions, so as long as the temperatures are low enough in the winter, populations are normally brought under control naturally. Unfortunately, much of western North America saw unusually warm winters in the late 1990s, warm enough to give allow pine beetles number to explode. There are now fears that if the warming trend continues according to the predictions of global climate change models, pine beetles could migrate into northern B.C. and even the Yukon, regions now beyond the insect's tolerance levels. As Hall points out, some organisms are extremely sensitive to temperature changes, and "one or two degrees change in climate can make a huge difference to insects." Safranyik cautions that we need much more data before linking a warming climate with increased pine beetle attacks. "Even during so-called normal conditions, 20 or 30 years ago, some years with mild winters and warm summers, we'd see beetles 80 to 100 kilometres north of their normal range," he says. With natural variability like that, drawing conclusions can be difficult. Meanwhile, the mountain pine beetles continue to thrive, proving yet again that nature is best left to its own devices.
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