A convoy of evacuees from Fort McMurray, Alberta drive past wildfires that are still burning out of control as they leave the city Saturday, May 7, 2016. The increasing frequency of wildfires in Canada’s boreal forest may be permanently changing one of the largest intact ecosystems left on Earth, new research suggests.THE CANADIAN PRESS/Ryan Remiorz

Fewer trees, less undergrowth: Study says wildfires changing boreal forest

Previous studies have found that the look of a forest is set early after a fire

The increasing frequency of wildfires in Canada’s boreal forest may be permanently changing one of the largest intact ecosystems left on Earth, research suggests.

“We feel pretty confident these effects will persist,” said Ellen Whitman, a forest ecologist at Natural Resources Canada and the University of Alberta.

Whitman is a co-author on a recently published paper examining what happens when stands of boreal forest — the huge belt of green that stretches over the northern reaches of most Canadian provinces — are burned over more often as a result of climate change.

She and her colleagues paired up forest areas that had similar climate and soil conditions and had last been burned by the same fire. One half had been previously burned no more than 17 years before, while the other half’s last fire had been at least 30 years ago.

The differences were striking.

The short-interval stands were far more open with fewer trees. Aspens dominated instead of conifers. Growth beneath the trees — shrubs and grasses that cover a normal forest floor — was far less luxuriant with many fewer species. Areas of exposed mineral soil, where all organic material had been burned off, were larger and more common.

They felt completely different.

“You have a landscape where you’re surrounded by short, stunted trees,” Whitman said. “You have a crust of lichen or some sparse grasses. It’s almost like walking through the edge of a prairie where you’re shifting from a grassland into a forest edge.

“At a lot of the long-interval sites, you’ve got quite dense conifers, closer together. You’ve got moss on the ground and flowers and shrubs. It’s more what looks like a young forest.”

The boreal forest has evolved for fire. Many of its tree species need it to germinate.

Normally, fires don’t come around more often than every 30 years and often much longer. The lack of fuel in recently burned stands helps regulate that frequency.

Climate change is breaking those rules, Whitman said.

“We’re experiencing more hot, dry windy days — the main trigger for large fire years. As more years experience more extreme fire weather, (the blazes) are able to overwhelm that resistance that recently burned sites have.”

Nor are the parkland-like areas likely to evolve into a conventional boreal forest. Previous studies have found that the look of a forest is set early after a fire.

“Immediate post-fire condition is an extremely strong predictor of what the stand will look like further down the road,” said Whitman.

Whitman emphasizes that short-interval stands in her research are still small and most stretches of boreal forest burned in recent wildfires are regrowing normally. Wetlands are also less affected by short-interval fires than drier regions.

She said the forestry industry is unlikely to be affected any time soon — although forest-dependent animals such as caribou and songbirds will feel impacts.

And those impacts are growing.

“With a longer fire season, larger fires, more of the landscape burning each year, the likelihood of encountering a recently burned area increases. We’re undergoing a shortening of the fire frequency in the boreal forest.”

READ MORE: Experts say climate change is driving up the risk of wildfires in Canada

Bob Weber, The Canadian Press


Like us on Facebook and follow us on Twitter.

Get local stories you won't find anywhere else right to your inbox.
Sign up here

Just Posted

B.C. firefighters only responding to most life-threatening calls during COVID-19 pandemic

The directive comes after province spoke with paramedics, fire services, according to top doctor

‘An extra $220 every 90 days’: B.C. patients pay more dispensing fees due to prescription limits

Kelowna woman says it’s outrageous to charge for refills every 30 days

Skeena Bulkley Valley MP calling for halt on sport fishing licenses to out-of-province fishers

Bachrach and Courtenay-Alberni MP Gord Johns co-signed the letter to the Minister of Fisheries

Bella Coola Heli Sports closed, says no confirmed cases of COVID-19 reported in their operation

The company has committed to informing the community if a case is reported

COVID-19 case confirmed at Subway restaurant in Cache Creek

Customers who visited the site from March 25 to 27 are asked to self-isolate

‘Better days will return’: Queen Elizabeth delivers message amid COVID-19 pandemic

The Queen said crisis reminds her of her first address during World War II in 1940

Emergency aid portal opens Monday, cash could be in bank accounts by end of week: Trudeau

Emergency benefit will provide $2,000 a month for those who have lost their income due to COVID-19

Education, not enforcement: B.C. bylaw officers keeping a watch on physical distancing

A kind word, it turns out, has usually been all people need to hear

COVID-19: Hospitals remain safe for childbirth, say Vancouver Island care providers

North Island Hospital has been asked to share its perinatal COVID-19 response plan

Canadian cadets to mark 103rd anniversary of Vimy Ridge April 9 virtually

Idea of Captain Billie Sheridan in Williams Lake, B.C. who wondered what to do in times of COVID-19

B.C. VIEWS: Pandemic shows need for adequate care home staffing

Seniors in B.C. care homes face challenging times

QUIZ: How much do you know about hockey?

Take this test and find out how well you know Canada’s most popular winter sport

Most Read