Climate change means more forest fires in Ontario. Here’s why

By Joshua Rapp Learn - Published on May 10, 2016
A forest fire near Red Lake, Ont, in May 1986. (Photo by Brian J. Stocks)

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While firefighters work to control blazes in Fort McMurray that caused the evacuation of the city of more than 80,000 people, researchers warn that climate change is making these kinds of wildfires more common across the country, including in northwestern Ontario.

Two fires were already burning out of control in northwestern Ontario as recently as last Friday, one of them causing around 100 residents from a seasonal village near Kenora to leave their homes. Parts of northwestern Ontario are now under fire restrictions after the Ministry of Natural Resources and Forestry determined there was a “high to extreme” risk of forest fires. But while the federal and provincial governments struggle to contain these blazes, some researchers say that increased wildfires in Ontario may become the new normal, especially in the province’s drier regions.

“Climate change is probably going to have the biggest impact in northwestern Ontario because that’s where it’s already the driest,” said Tim Lynham, a forest fire research project leader with the Canadian Forest Service. “A little bit drier is going to mean a lot more fire.”

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He says that the rise in temperature due to climate change is partly responsible for a huge increase in forest fires across Canada. “We’ve approximately doubled the area burned since 1970, and conservative estimates are that we’ll double it again this century.”

On average 2.3 million hectares burn per dry season across Canada, but Lynham says that five of the past six years have seen far higher than average figures: as much as six million hectares, or about the size of Nova Scotia.

Most of this has primarily affected the western and northwestern parts of the country so far. Jolanta Kowalski, a spokeswoman for the Ontario Ministry of Natural Resources and Forestry, wrote in an email that as of May 5 the number of fires has been close to normal across Ontario, with 68 incidents and 86 hectares burned, but ongoing fires since then are driving up these numbers.

She said the last two years, which experienced polar vortex winters, have actually had a lower than average numbers of fires. The province anticipates around 1,100 annual fires that burn around 110,000 hectares, but 2014 and 2015 only had around 982 fires burning 49,000 hectares — 22 per cent of the total area expected.

However, she noted that increasing extreme weather is leading to more wind events, which uproot trees on large tracts of forest and leave areas highly susceptible to fire. Also, droughts or hotter temperatures, both of which are becoming commonplace across the country, can increase fire probability. “Extended heat waves can cause excessive drying of forest fuels causing intense wildfires that are difficult to control,” she wrote.

This trend seems to be moving into northwestern Ontario, where it could affect communities such as Thunder Bay, Sioux Lookout, Kenora and Red Lake, according to Lynham.

This year could be an especially bad one. Lynham says that the dry conditions that sparked an early fire season in the west are moving towards Ontario. Many parts of the boreal forest still sit in a limbo between seasons, in which the snow is long gone but the rain hasn’t sparked much green growth yet.

“Obviously if you’re looking at a dynamic climate condition, that’s going to affect vegetation,” says Fred Pinto, the executive director of the Ontario Professional Foresters Association. He says that this will certainly have an effect on forest fires, and Lynham says that these conditions are setting the province up for a bad spring.

“The vegetation hasn’t flushed green for the new year. It’s still dead and dry from last year and that’s making the problem much worse,” Lynham said. “If we have any hot and dry weather and high winds, and if we get any lightning, then we’re vulnerable.”

It's not just changing weather that threatens to cause more forest fires. The boreal forest of Ontario and Quebec is currently due for a generational plague of spruce budworms, which hit natural population peaks every 34 to 38 years when the insects eat the needles off all the spruce and balsam fir in their path.

“It’s going to create mortality in spruce, particularly in balsam fir and those trees will make the forest more vulnerable to fire,” Lynham said. The worst time occurs from four to 10 years after an infestation, when the tops of the dead trees fall off and knife into the ground, creating a kind of a ladder for flames to move between the forest floor and the canopy. “Those are some of our highest intensity fires.”

Also, mountain pine beetle infestations are moving eastwards from Alberta while the hemlock looper is spreading west from Quebec and the Maritime provinces towards Ontario. All of these insects kill trees, and as climate change makes the forests drier, they will be a lot more flammable.

As the climate warms and brings more dry conditions, it could exacerbate the normal ebb and flow of a flammable forest. Peatland is thawing in the northwest, which opens up more land for burning.

Canada spends around $1 billion annually fighting forest fires, and, while the crews who douse the flames have new tools and technology, Lynham says that resources are sometimes spread thin for provinces and the federal government. All provinces and territories are responsible for fighting their own fires while the Canadian government handles flames in national parks. But since fire doesn’t hit everywhere equally, resources are often shared.

Lynham says that Ontario firefighters are currently in Alberta, or on their way to help control the Fort McMurray wildfire. Here in Ontario, the province is ramping up its training to get more recruits up to speed in case something happens on home soil.

“While one part of the country may be experiencing wetter than normal conditions, another part may be extremely hot and dry,” Kowalski says. Ontario hasn’t yet seen any increase in firefighting budgets due to climate change and recently mild fire seasons, but has been able to help out other provinces during this time.

Weather is only partly to blame. Humans cause around half the fires that are close to communities and these tend to be the more dangerous ones. The other half occur in remote areas and are usually caused by lightning strikes, which Lynham says are becoming more frequent.

Lynham worries this could increase budgets in Ontario and across the country and put more communities like Red Lake, Ont., in danger. The area continues to experience drier, warmer conditions, and has already seen fires nearby over the past few decades. But if one occurs to its west, it could be devastating to the community as the forest there is prime for burning. “The prevailing winds come from the west so it’s the fire that might be the most intense and the most difficult.”

An increasing fire regime could also affect the ecology of the boreal forest, which usually thrives on wildfires as long as they happen every 60 to 150 years. Pine trees need about 30 years to start producing cones which drop seeds during the extreme heat produced by fires. But if flames become more common, they may have an impact on a forest’s ability to regenerate. “They may not be producing seeds fast enough,” Lynham says.

Joshua Rapp Learn is a freelance science writer. This bio has been corrected from an earlier version that incorrectly listed Learn as a writer at The Wildlife Society.

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