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

The value of a prison education

Kevin Heinze teaches continuing education at Fraser Regional Correctional Centre in Maple Ridge.

Along the Fraser: RIP Parker (1991-2019)

The Canadian Liver Foundation raises funds by recycling or scrapping old vehicles.

Letter: Allen Way rail crossing proposed in 1980

Pitt Meadows mayor at time wanted it at north Bonson.

Maple Ridge group gives back to northern places

Teaching how to grow in isolated First Nations reserves

Maple Ridge school hosts FIRST LEGO competition

Students build and program LEGO MINDSTORMS to find solutions to city landscape designs

Canada Post driver in hospital after ice smashes windshield at Massey Tunnel

Incident happened on Richmond side of the Massey Tunnel

B.C. society calls out conservation officer after dropping off bear cub covered in ice

Ice can be seen in video matted into emaciated bear cub’s fur

Calls for dialogue as Coastal GasLink pipeline polarizes some in northern B.C.

Coastal GasLink is building the 670-kilometre pipeline from British Columbia’s northeast to Kitimat on the coast

Coquihalla, Highway 3 to be hit with freezing rain, sparking warning to commuters

Hard to say when the freezing rain will turn to regular rainfall, Environment Canada says

VIDEO: Newbie Vancouver Giants leads victory over Victoria 4-1 Friday

The G-Men play Saturday in Victoria before hosting Kamloops on home ice in Langley Sunday afternoon

Closed mills, housing surge support a positive forecast for lumber industries

B.C. lumber producers have closed mills accounting for 18% of province’s capacity, RBC report says

Good Samaritan pays part of rent for B.C. woman facing eviction in can-collecting dispute

Zora Hlevnjak, 76, supplements her pension by collecting cans and receiving public donations

Should winter tires be mandatory in the Lower Mainland?

ICBC dial-a-claims go up as winter storm takes toll

Most Read