Allan Carroll, Uncut

(This is the full interview; read the edited version that appeared in the print issue of Momentum)

Allan Carroll, associate professor of forest sciences with the University of British Columbia, spoke with Momentum in March 2011 on the impact of mountain pine beetles on forests in British Columbia and other parts of western North America. See photos of pine beetle damage.

What’s the role of climate change in what’s happening up there?

We actually have identified an extremely strong climate signal in the mountain pine beetles. So the mountain pine beetle movement has been significantly affected by climate change. But it’s really worthwhile pointing out that the outbreak itself is also the consequence of two significant factors.

The first one, and this is relevant not only to British Columbia but also for the south into the U.S. and even further east into Alberta, is that we have, through our forest management practices, created enormous amounts of mature pine forests over the last decade, and that is in effect mountain pine beetles’ preferred food source. So we’ve created a real smorgasbord for the beetle, largely through practices such as fire suppression, and this is very relevant in British Columbia. And also to a lesser degree, past practices of selective harvesting, where we’ve left pine on the ground and removed the more preferred species at the time, which would have been things like Douglas fir and spruces, and so on and so forth. Those things together have really made a mass area of food for the beetle, which has allowed it to be spread over huge, huge areas very quickly.

Now to come around to climate, the mild winters and indeed the warm summers, which are almost equally important for mountain pine beetle, have helped the population grow and spread. Where we’ve found the irrefutable climate signals is the fact that the mountain pine beetle is beginning to move into habitats that it hasn’t normally been able to occupy because of climatic limitations. Now, pine species occur throughout British Columbia, and in fact they go north into the Yukon and Northwest Territories, and then of course they go throughout Alberta and ultimately across the boreal forest. And historically, the mountain pine beetle has never been that far north, simply because the climatic conditions have been unsuitable for them. It’s both too cold in the winter and not quite cold enough in the summer.

So the beetle is not only moving south from British Columbia, it’s also going east, and that’s the surprising part?

From a Canadian’s perspective, that eastern movement and its threat to the boreal forest across the continent is the biggest concern that we’ve got.

How far east has the beetle gone now?

They’ve actually detected beetles most of the way across Alberta now. As far as Fort McMurray is the latest detection of beetles toward Saskatchewan.

I visited Yellowstone a couple years back and saw the massive devastation there. Is it the same species of beetle?

It is. The mountain pine beetle has an enormous range. It goes from Northern Mexico right up into western Canada, so it covers a huge area and it is a native insect, so it’s not introduced, which surprises some people. The issue with it moving into new areas as they become warmer is one that’s sort of driving this whole issue of northward and eastward expansion, but you also see that in the south in the U.S. where it’s moving higher in elevation. And if you’ve been to Yellowstone you’ve certainly seen it perhaps killing some of the high-elevation pine or white bark pine, which are so critical as habitat for other species like grizzly bears.

I read a quote recently that said this outbreak is 10 times worse than previous outbreaks. How do we know that for sure?

Essentially, that quote should be caveated by the addition of “within recorded history.” And as we have discussed whether or not the outbreak is unprecedented, and given that we have, for example, in British Columbia over three times as much mature pine in the landscape at the start of this outbreak as we had a hundred years previously, that’s the critical factor driving the massive size of the population. And that’s directly related to anthropogenic, or manmade, fire suppression activities. One can sort of make the case that we’ve probably had previous outbreaks but we’ve not had them of the size that we have this one because we weren’t putting out fires in the past.

What is the response of the forestry industry up there in B.C.? Has there been concern?

The projections for the problem in British Columbia are that we’ll lose two-thirds of our mature pine before the end of the outbreak. And given that much, and certainly the majority of forest activities around the generation of lumber actually focuses on pine, that’s a real big thing.

It’s interesting to consider that early on, prior to 2008, before the economic downturn, there was a real boom going on in British Columbia simply because there’s an incentive around harvesting the dead trees before they rot. Typically forestry has to be conducted in such a way that it’s considered to be sustainable—in other words, we don’t remove from the forest more than what grows annually. But in the case of an unprecedented event like the mountain pine beetle, there are accommodations to the pine companies to harvest as much as they can before it’s lost to decay. And when doing that of course, the U.S. market could absorb most of what we could produce, everything was grand. And then in 2008, with the downturn of the economy, of course we lost the market and we’ve had many, many of our forest companies shut down mills and suffer economically quite negatively.

Has there been a movement to try harvesting the dead trees and converting them to a biofuel?

There’s actually been an enormous amount of research going down that road toward some biofuels applications for all of these dead trees. The real unfortunate part of it is at this point we have yet to find some sort of application that is economically viable. There’s a lot of costs associated with harvesting these trees and bringing them to some central location where they can be either chipped and produced into pellets or used in cogeneration along with, say, coal or whatever the case may be, or simply burned outright for the production of steam. That’s highly expensive and in fact, here in British Columbia we have had a fairly vibrant biofuels component to our forestry, but it’s only been viable because it’s actually driven off the residuals, the leftovers from sawmills that they get for free. So you see, when you add even a minor cost to the whole equation, it all falls apart. We’re waiting on new developments hopefully that will come online and will make this sort of a thing a bit more functional.

Has anybody put a number to the economic impact of the mountain pine beetle damage?

That number is a tough one because of course it’s predicated on some notion that you can actually understand what the future market would have been. And so as a result you never quite see one solid number. Early on, the Council of Forest Industries in British Columbia was putting out numbers, but it’s really, really hard to find anything anywhere that says, “The cost of the outbreak is X amount of dollars.” I think if you put it back into that prediction around somewhere in the neighborhood of a billion cubic meters of wood killed, you can make extrapolations from that saying that if the market had been X amount of dollars per cubic meter, then things would have been just fine, or otherwise. But it’s a tough one to say.

What about the loss of carbon sequestration potential from all the trees that are being killed in B.C.?

I co-authored a paper that we published in Nature recently where we actually discussed the carbon implications of the mountain pine beetle. We showed, in fact, the beetle has turned the forests of British Columbia from a net sink to a very significant source. We projected forward to 2020 and found that the emissions caused by the beetle’s destruction of trees are roughly about a billion tons of CO2 to the atmosphere and the equivalent to about five years’ emissions from the entire transportation sector of the entire country of Canada.

Read Allan Carroll’s Nature paper.

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    The Momentum event series brings today’s leading environmental visionaries to the Twin Cities to deliver thought-provoking presentations.