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

Kelowna glider pilot crashes in the Columbia Valley

The Transportation Safety Board is investigating the circumstances of the crash

MP Morrison pushes for accountability following federal fiscal update

Kootenay-Columbia parliamentarian says it is time to restart the economy

UPDATED: Interior Health to add 495 long-term seniors care beds

Nelson, Kelowna, Kamloops, Vernon and Penticton to receive new facilities

QUIZ: Are you ready for a summer road trip?

How much do you really know about roads, motor vehicles and car culture? Take this quiz to find out.

B.C. records 62 new COVID-19 cases, two deaths since Friday

Province has just over 200 active cases

Summerland approves solar project

Despite community opposition, council voted 4-3 for Cartwright Mountain location

Police search for suspect in assault on woman in downtown Kelowna

Kelowna police received a report a woman had been assaulted by an unknown man on July 12

Hotel rooms for B.C. homeless too hasty, NDP government told

Businesses forced out, but crime goes down, minister says

Two positive COVID-19 cases at Oliver farm

The risk of exposure to the general public related to this farm is considered to be low

Oliver Town Hall closed to public as staffer displays COVID-19 symptoms

One staff member at Oliver Town Hall is being tested for coronavirus

Wage subsidy will be extended until December amid post-COVID reopening: Trudeau

Trudeau said the extension will ‘give greater certainty and support to businesses’

B.C. government prepares for COVID-19 economic recovery efforts

New measures after July consultation, Carole James says

Horoscopes for the week of July 13

Weekly horoscopes by Morgan Fava

Most Read