Jasper used to burn often. Why did that change when it became a national park?

Decades of work to suppress fires in Jasper National Park may have inadvertently contributed to conditions that fed a devastating wildfire that ripped through Jasper in July, experts say.

The fire, which burned down one-third of the buildings in the Jasper townsite, was the largest in the national park in over 100 years, according to Parks Canada. The fire consumed more than 33,000 hectares before it was classified as being held.

While fires are not uncommon in Canada's Rocky Mountains, studies suggest the number and size of fires has significantly decreased over the last century, including in Jasper National Park, largely due to suppression.

"We conclude fire suppression has altered the fire regime and reduced resilience of the mountain forests in Jasper National Park," Raphael Chavardes and Lori Daniels wrote in a 2016 research paper. The paper was part of Chavardes's master's degree at the University of British Columbia and Daniels was his supervisor.

Chavardes studied the forest 12 kilometres north of the Jasper townsite. He now works for the Canadian Forest Service as a fire risk and resilience research scientist.

By detecting fire scars on the cross-section of trees that were more than 400 years old, Chavardes determined there had been no fires in his study area for 100 years. 

However, Chavardes said, prior to Jasper becoming protected in 1907 by the federal government, the forest burned about every 40 to 60 years, on average.

"There's a rich history of fire in the park," he said. 

Fire records for the park show there were large fires in the valley around what is now the townsite in 1758, 1847 and 1889, and a smaller one in 1905, according to a 1979 study by Gerald Tande, a researcher at the University of Alberta.

After that it was relatively fire-free for decades.

The Chetamon wildfire, about 15 km north of the townsite, burned about 6,000 ha. in 2022 and severed power to the community for several days. It had been the largest fire in the area in decades until this year's massive blaze. 

More than 100 years after the building of the townsite, the park is a top tourism destination that brings millions of people to the area. 

The lack of fires for more than a century was likely due to fire exclusion and suppression by Parks Canada, said Chavardes. "It was to protect timber and stop fires from burning," he said.

Look at how the forest near the Jasper townsite changed over the last 100 years: