Black Plague

Mountain pine beetles have chomped their way through B.C. and are now showing up east of the Rockies. Will cutting down trees save the forests?

In the spring of 2002, as many as 30 million beetles, each about the size of a kernel of wild rice, fell from the sky over the green forest blanketing the eastern slopes of the northern Rocky Mountains.

The event wasn't witnessed by anyone but has been reconstructed with some certainty by scientists who study bugs. Entomologists now believe the beetles became airborne somewhere 400 kilometres or so to the southeast, near the community of Prince George.

They were undoubtedly part of a small subset of the population--roughly 2.5 percent--that moves from forest to forest by flying over the tops of trees rather than through the foliage. Taking the flight path less travelled has advantages in that distances can be closed quickly and without obstruction. But from a species-survival perspective, it is risky. One strong wind or air current can sweep the beetles away, perhaps delivering them to a hostile environment such as an ice field.

In this case, however, luck was on their side. Sucked thousands of metres into the sky by strong convection currents, the beetles were swept northeast in a state of near hibernation. They didn't fly so much as they were hurled clear over the top of some of North America's highest mountains, then dropped on the other side into a forest filled with pine trees. A year later, scientists would note with alarm how tiny patches of "evergreen" trees there were now a rusty red and dying. It was the first undeniable evidence that mountain pine beetles had crossed into, for them, previously uncharted territory.

Historically confined to the dry Interior of British Columbia well west of the Rockies, the beetles had overcome an imposing and, so many people thought, impassable natural barrier. Before them lay the rolling Peace River country and, not far distant, the edge of the Boreal forest, which stretches from northeastern B.C., across the northern half of the Prairie provinces, through Ontario and Quebec's Canadian Shield country, and on into the Maritimes. One of the most dominant tree species in the Boreal zone is jack pine. If, as some entomologists and foresters fear, the beetles gain a beachhead there, we could witness one of the greatest cataclysms ever to befall the Boreal forest, the world's largest. The big question is this: can and should the beetles be stopped? And if so, how?

PERHAPS THE MOST troubling aspect of the calamity now befalling the Interior forests of B.C., where millions of pine trees have been killed by beetles and many millions more soon will be, is that there really was no single starting point for the current outbreak. Yet a story persists, one that has been fuelled by politicians, civil servants, and forest companies alike, that the outbreak began in the early 1990s in Tweedsmuir Provincial Park, where it could have been contained through logging and burning. A "hands off our parks" mindset, so the story goes, blinded people to the dangers ahead. And the result was that in very short order an unstoppable army of beetles was marching across central B.C., destroying billions of dollars worth of timber and creating massive fuel stores for future forest fires.

On computer-generated maps in the offices of B.C.'s Ministry of Forests, it is clear, however, that although Tweedsmuir was a beetle hot zone, hundreds of smaller infestations were occurring simultaneously between Nelson in the southeast and Fort St. James in the distant northwest. It was as if the green pine forest had suddenly developed a bad case of the measles. There were red spots everywhere, each threatening to turn into angry rashes. And whether the spots were near Merritt or Princeton or Kelowna or Cranbrook, they could not be traced back to events in a distant northern provincial park. No, something much bigger was at play here.

The other story that continues to have legs is that this problem, big and bad as it is, could be brought under control if only we got a severe cold snap in the late fall, early winter, or early spring. Mountain pine beetles may be as far removed from sexy fauna as one can get, but they are evolutionary miracles nonetheless. As Allan Carroll, an entomologist with the Canadian Forest Service, explains with animated wonder, the beetles produce glycerol, nature's antifreeze. Frogs and certain northern fish species employ similar defence mechanisms. This makes the beetles very hard to kill except under extreme cold. "The last mountain pine beetle outbreak to really make forest scientists pay attention occurred on the Chilcotin Plateau in the early 1980s and concluded around 1984-85 with the arrival of some very cold and--this is crucial--early cold weather. Specifically, minus 35 degrees around Halloween," Carroll said at his office in the Pacific Forestry Centre, the Canadian Forest Service's regional headquarters in Saanich.

Despite our current warming trend, we could get such temperatures again and at precisely the right time, Carroll says. The problem, though, is they wouldn't be cold over the huge area now infested. Likely only a small fraction of forest would be chilled sufficiently. There is only one time that climatologists can confidently claim that extreme cold would have prevailed over the millions of hectares now infested by the beetles. It was about 13,000 years ago and involved ice, a lot of it.

So, barring another Ice Age--which would solve the beetle problem but create its own unique set of challenges--what awaits us? Carroll and other forestry professionals suggest that the most likely scenario is a continued attack that will consume many millions more trees. And the result won't be pretty if you're a company that makes its living from the forest or a provincial government relying on the hundreds of millions of dollars in annual timber-cutting fees and other revenues associated with logging activities.

Two things have conspired to create this situation. The big one is our warming world, which is opening new frontiers for the beetles. But the other, far less appreciated, reason is that we have an awful lot of older pine trees on the landscape, many more than a century old. In fact, three-and-a-half times more. Prior to the arrival of Europeans, much of the forest now being attacked routinely burned, sometimes in small patches following lightning strikes, at other times over vast areas with little islands of forest left behind, isolated oases of green in seas of blackened spires. The human hand was here too. Native people deliberately set forests alight, creating open spaces for berries, deer, and other sources of food.

All of this burning by nature and humans had huge ecological benefits. First, these forests couldn't evolve without fires. The licking flames caused pine cones to fall and release the tough heat-resistant seeds that would germinate in the thin layer of exposed organic soil. Second, the forest became a patchwork quilt following the fires. The result was that in one stretch of forest the trees might be 30 years old, while nearby they were upwards of 120. Although much of the forest was composed of only one tree species--lodgepole pine--it was healthy because of its diversity of ages.

All of this started to unravel in the decades after European contact. In the early records of the Hudson's Bay Company in places like Fort Victoria, there are exasperated references to "the Indians burning again" and efforts being made to stamp out such practices. The consequence was the removal of one of the most fundamental building blocks in forest evolution and a creeping monoculture, the arboreal equivalent of 19th-century Ireland's ill-fated fixation with the potato.

"We've taken fire out of the system, in large part," Carroll says, "and in doing so all of the forests that would have normally burned and reset to zero have not been. They've been allowed to age." And advancing age always brings problems.

IN WHAT CARROLL calls the "ecological arms race" between the bugs and trees, the preponderance of older pine has tipped the scales in favour of the beetles, who are remarkably adept at killing living organisms many thousands of times their size.

An attack of a new tree always begins with the arrival of a single female beetle. After boring into the tree, she uses the chemistry of the tree bark to create and emit a powerful pheromone. As noted in Fumigants and Pheromones, "a newsletter for the insect control and pest management industry", more than 1,000 of these chemical messengers have been identified worldwide since the discovery of the first one by German scientists working with silkworm moths in the 1950s. The discovery led to the coining of the word pheromone, a hybrid of two Greek words, homan, to carry, and pherin, to excite.

In addition to acting as attractants that draw in members of the opposite sex for mating, pheromones can also send a much different kind of signal, such as "Back off, don't come near me!" The release of the pheromone from a tree just under attack is often enough to lure several males. And as the males begin boring into the tree, they produce more pheromones, attracting more females.

The attacked pines are not necessarily powerless in the face of this pheromone-induced boring orgy. "The tree's response to the invasion is to produce a whole bunch of resin--pitch," Carroll explains. "And it does so through resin canals that initially attempt to flush the beetles out of the tree. Then there's a second wave of pitch produced by the tree, which is even more toxic than the first."

When beetles are at normal background levels, Carroll continues, this may suffice to save many trees and blunt the forward momentum of an outbreak. However, with today's massive beetle numbers, more and more trees are being overwhelmed. In addition to deploying the pheromones that call in the added troops, the beetles also come armed with deadly spores. Housed in the beetles' mouths, the spores are released within the tree. There they penetrate the cells, creating a fungus that leaves a distinct blue stain in the tree's core. If the release of spores is sufficient, the tree's defences shut down.

In the late summer following a tree invasion, female beetles lay their eggs. The eggs hatch within a couple of weeks, and the emerging grubs bore circularly around the inside of the tree while the fungi continue colonizing. Eventually, the grubs excavate little chambers in the trees in preparation for becoming pupae. The fungus then migrates into the chambers. Late the following spring, the pupae transform to young adults. Not yet able to fly, the young adults feed on the only thing handy--the spores. About two weeks later, when the beetles fly, they carry spores with them, and the cycle resumes.

Evolutionary biologists might not call the relationship between the beetle and spores a match made in heaven, but few would question its grand design. "The beetle uses the fungus to gain access to a tree it wouldn't normally have access to...And the fungus uses the beetle as a means of dispersal, hitching a ride from tree to tree," Carroll says.

In an added insult to the trees, if the ride the spores hitch takes them toward a tree where enough beetles are doing their deadly job, then the attacking insects already there produce an "anti-aggregation" pheromone, which essentially says "Go away, we're busy." Not far off, the beetle-spore tag team finds another host tree.

THE BIG CONCERN now is just how many new hosts are likely to be visited in the near and not too distant future. According to a public discussion paper released in June by B.C.'s chief forester, Larry Pedersen, one out of every two lodgepole pine trees in the province's Interior could be infested by the end of 2006. In 10 years, as many as four out of every five pine trees could be attacked. Such figures become even more mind-boggling when one considers, as someone in Pedersen's position must, just how many "harvestable" trees we're talking about. Pine trees are the species most commonly logged in the Interior. And in the Prince George, Quesnel, and Lakes "timber supply areas"--where the outbreak has been most damaging--almost two thirds of all the trees that can be logged are pine.

"Based on my review of the mounting information about the epidemic and its potential impact on timber supply and forest habitats, I believe there are compelling reasons to review the timber supply and harvest levels in the three severely infested areas," Pedersen reported in June.

In plain English, what this means is that Pedersen may soon approve a whopping increase in logging rates in the most heavily infested areas. The increase will, if past decisions are an indication, be justified on grounds that the dead trees must be "salvaged" before they lose most if not all of their commercial value. This is not to be confused, however, with attempts to stop the beetles in their tracks by logging all the trees along the numerous edges of attack. That stopped being an option a few years ago, when scientists realized there were too many beetles in too many places. Indeed, stopping the beetles now would be about as easy as a beach bum trying to suck up an incoming wave with a straw, says Marvin Eng, a researcher and landscape ecologist with the Ministry of Forests.

Sitting in his Victoria office at a desk piled high with reports and maps, Eng turns to his computer, where he walks a visitor through a simulated projection of the outbreak. The outbreak's spread is highlighted in red, but it also has a nifty added feature that shows the intensity of the outbreak over time. As the beetles gain in number, the areas of red begin to form into mountains. The more intense the beetle infestation, the higher and steeper the mountains become. Eventually, the mountains subside. But at that point, pretty much everything in a wide band running from Cranbrook in the southeast to Fort St. James in the northwest has been coloured red, with troubling spots of infestation outside that long corridor in regions like the northeastern slopes of the Rockies.

After running through the computer simulation, Eng turns and says that 2003 was an "astounding" year for the infestation, particularly in the area between Prince George and Quesnel. "And that was last year. All those beetles are coming out and they're going to create even more damage this year. Even if we took all the cutting horsepower in the entire province, and it's hard to imagine how we could apply that, even then it wouldn't make a difference."

SO JUST WHAT does the envisioned mop-up look like? To get an idea, you have to go back 20 years to when the last great wave of beetles swept across parts of B.C.'s Interior, in particular the vast Chilcotin Plateau west of Williams Lake.

At that time, the word unprecedented was bandied about to describe the rate at which pine trees were turning red and dying. By the time it was over, some 400,000 hectares of land were affected, roughly the size of Vancouver Island.

Unable to stop that outbreak, the government of the day ordered a "temporary" increase in logging rates. An additional 1.25 million cubic metres of timber was assigned to local sawmills, and in 1985 an orgy of logging, the likes of which residents had never seen, was unleashed on public forest lands. Remote landowners several hours' drive west of Williams Lake would later report the arrival of feller bunchers into forests previously believed beyond the reach of Williams Lake's sawmills. The heavy machines, which move over ground on treads, have large arms that extend from control cabs. At the end of the arms are clasps that firmly grip the base of trees and through which rapidly whirring saws pass. Equipped with powerful lights, the machines can operate at night and cut thousands of trees in a day. And throughout the late 1980s and 1990s, they did just that, over and over again.

It is a sign of just how big the last outbreak was that what began as a temporary measure to salvage some of the attacked trees turned into a semipermanent feature on the plateau. When the first salvage licences expired in 1989, they were renewed again, albeit at a slightly lower rate of just under one million cubic metres a year. Further renewals followed again in 1991. But this time, the date of expiry was extended until 2000. What all this meant was that over a 15-year period, a vast area of forest was logged over and above the "sustainable" levels as calculated by provincial foresters.

How much more? All the wood that was salvaged amounted to 15.6 million cubic metres. What does that mean? Well, you'd need more than 445,000 truckloads to carry that wood. And what does 445,000 truckloads equate to? Line trucks bumper to bumper from Vancouver to Halifax and back again as far as Brandon, Manitoba, and you have the answer.

Part of what made it possible to run a salvage program of that scale and duration was that the Chilcotin Plateau is a very dry place, and that allowed many of the attacked trees to hold commercial value long after the attack. But this time out, things are different. Many of the areas now infested are in damper locations where attacked trees will rapidly lose their optimum commercial value. "While beetle-killed trees may remain standing for up to 20 years," Pedersen reported, "their merchantability as sawlogs and recoverable lumber will decline quickly within the first few years."

This is forcing civil servants and provincial politicians to consider a logging program on a scale well beyond that witnessed on the Chilcotin. Two years ago, Pedersen approved salvage-logging increases of 5.5 million cubic metres per year in the Prince George, Lakes, and Quesnel areas. Now, in an effort to get at as much beetle-attacked wood as possible, he's considering doubling that again for a period of at least five years. The cumulative impact of all that additional logging would be 66 million cubic metres of wood over seven years--more than four times what came out of the Chilcotin and in less than half the time. And these increases do not include any others that could occur in the same area or elsewhere in the province where the beetles are busily doing what nature programmed them to do.

On the positive side of the ledger, all of that additional wood could provide a much-needed infusion of economic activity into rural B.C.'s resource-dependent central Interior. But the downside, and it's a big one, is that overeating today means dieting tomorrow. Pedersen's predictions on future logging activities in much of the Interior indicate that following an unprecedented period of salvaging, future logging rates will eventually fall to half of what they once were. And that will undoubtedly mean mill closures and economic hardship in many Interior communities.

It is possible that this grand liquidation program may not get off the ground, though. For one thing, the wildfires now consuming hundreds of square kilometres of pine forest are doing their own job of dealing with beetle-ravaged tracts of forest. For another, the powerful U.S. softwood-lumber lobby would not look kindly on a sudden surge in pine-lumber shipments from the province. "We don't want to flood the American market," says Atmo Prasad, a Victoria-based timber supply forester with B.C.'s Forest Service.

Then there's the whole issue of who would process the masses of added wood. Even going flat out, the existing sawmills cannot handle it all. And as the attacked trees become valueless for lumber, other uses would have to be found. The government is encouraging new proposals from industry. One idea envisions new plants that would shred millions of logs for oriented strand board, a poor man's substitute for plywood. Another includes burning the wood to fuel electrical cogeneration plants. But these ideas will require hundreds of millions of dollars in private-sector investments--a shaky proposition with a resource that is rapidly deteriorating and, in many cases, a fire waiting to happen.

CARROLL DOESN'T ENVY Pedersen. It's a tough position to be in. On the one hand, the chief forester has social and economic considerations to address. On the other, he has a forest to look after. And it's from the forest that the social and economic values flow.

Salvaging makes sense in that it recovers economic value. But if it's done at too great a scale, we could be setting the table for future beetle outbreaks of a similar size and ferocity. All that additional clear-cut logging will reset vast areas of forest to zero at precisely the same time, creating a massive monoculture and food source for future generations of beetles.

"We could get ourselves into a vicious circle if we're not very, very careful," Carroll says.

In our responses to this outbreak, Carroll continues, we have to do as much as we can to emulate natural disturbances, to create a patchwork quilt of pine that is uneven in age and resistant to the blood-red tide being loosed upon the land. Simply going in and mowing down as much as is humanly possible may not be the way to go.

Where we can and should be aggressive with our logging, however, is at some key points on the eastern flanks of the current outbreak. Unusual as the airdrop of beetles onto the northeastern slopes of the Rocky Mountains was two years ago, it was not unexpected. The growing consensus among foresters and entomologists was that the logical outcome of the northeasterly thrust of the outbreak would carry the beetles into the Peace region by land. The airdrop simply accelerated the arrival.

Two forest companies now find themselves in the unique position of possibly being able to stop the beetles from moving from that position further northeast into the Boreal forest. Brian Pate, a forester with Chetwynd Forest Industries, a division of West Fraser Timber, says that between his company and Canadian Forest Products they probably have 60,000 trees that were infested in the Peace in 2002. Given attack rates, it's possible that number is now double that.

To bring the problem under control, the companies must be able to quickly identify the new trees that have been attacked and log them before next season. And they must also be able to contain any future outbreaks. This is a demanding task because the currently attacked trees are scattered over 1,500 or more pockets of forest. And newly attacked trees are not readily identified by air, as it takes a full year for their green needles to turn red. But it's vital that this work be done, Carroll says.

"You have to go in there and remove and destroy all the trees with beetles in them," he says. "Vigilance at this point is key. If we treat the attacked trees like fires, get at the ignition points quickly and put them out, we might stop the advance."

Work being done by Carroll's colleagues at the Canadian Forest Service also suggests that in some areas along the advancing flank of attack judicious and early thinning of trees may help. Thinning involves selectively logging individual trees and creating space for the remaining trees to put on new and vigorous growth. This might delay such forests being overwhelmed for 20 or so years.

If company and government foresters forsake such vigilance, however, Carroll says we all should be very worried. The vast Boreal forest is filled with pine trees. And while jack pine are different from lodgepole pine, tests conducted in CFS laboratories show that the beetles could do very well in the Boreal, thank you very much.

"Yes, they can make a living in jack pine. And yes, they can mass attack in a way that lends itself to the maintenance of an infestation," Carroll says.

Give them a home there, and all bets are off.