Fact File: Does banning glyphosate-based herbicides prevent wildfires? Here’s what we know

A social media post shared a screenshot of a satellite map that shows Quebec experiencing fewer wildfires than the rest of Canada, and suggested it was because the province banned the use of glyphosate-based weed killers in 2001. Experts who study wildfires say Quebec has seen varied wildfire seasons since then — including an extreme burn in 2023 — despite a lack of glyphosate use. They say there is no evidence linking glyphosate to increased wildfire activity.

THE CLAIM

“Ahead of this wildfire season it is always important to remember that Quebec is the only jurisdiction in North America that doesn’t spray its forests with glyphosate for ‘forest management,'” reads an X post from last month with around 11,000 likes.

The post includes a screenshot of a “2025 wildfire map” that appears to mark wildfires across Canada and the United States with a flame icon. It bears the watermark of the Fire Information for Resource Management System US/Canada, a satellite fire map maintained by NASA, and the date Aug. 20, 2025.

The majority of fires on the map are clustered in Western and Central Canada, while Quebec seems to have the fewest fires.

The post suggests Quebec saw fewer fires than the rest of Canada because it does not use glyphosate on its forests.

Some of those who shared the post elsewhere on social media mused glyphosate could be accelerating forest fires elsewhere in Canada.

A similar X post to the one shared last month was posted by the same user in August 2025 and reshared on multiple social media platforms.

THE FACTS

Glyphosate is a herbicide that is widely used for agricultural management in Canada.

Provinces including British Columbia, Ontario and New Brunswick use glyphosate-based weed killers in forests to get rid of species that compete with conifers, the trees preferred by the forest industry.

Quebec banned the use of glyphosate in its public forests in 2001.

While there are legitimate health risks associated with glyphosate, Health Canada maintains its use does not cause harmful effects for Canadians if the products containing it are used according to label instructions.

Nelson Thiffault, a research scientist with the Canadian Forest Service, said wildfire occurrence and severity depends on a complex mix of factors.

They include weather conditions, drought, temperature, wind, ignition sources and topography, he said in email to The Canadian Press.

“I’m not aware of any scientific evidence supporting the claim that Quebec has fewer wildfires because it banned the use of glyphosate in public forests in 2001, nor that glyphosate use is a primary driver of wildfire activity,” Thiffault said.

Climate and weather would typically have the biggest impact on annual wildfire activity, he added.

Robert Gray, a fire ecologist and consultant, said glyphosate can make forest landscapes more flammable.

“It’s converting live vegetation to dead vegetation and that changes the dynamics of fire behaviour,” he said in an interview.

Thiffault said forest management practices that prioritize conifers create forests that are generally more flammable than those with more deciduous species, whose higher moisture content reduces fire intensity.

“However, these outcomes are shaped by overall management objectives and silvicultural systems, not by any single treatment tool in isolation,” he said.

Jonathan Boucher, also a research scientist with the Canadian Forest Service, said there isn’t enough data to show glyphosate has a direct impact on wildfires, especially as other provinces use multiple methods to reduce the abundance of deciduous species.

He added the map shared on social media is a snapshot in time that doesn’t reveal much about wildfire behaviour in Canada.

“There’s a high variability from year to year, but also from regions to regions,” he said of Canada’s wildfire landscape in an interview.

The researchers who spoke to The Canadian Press noted that Quebec experienced an unprecedented wildfire season in 2023, disproving social media conjecture about Quebec having fewer fires than other provinces as a result of its ban on glyphosate.

He noted Quebec saw more than four million hectares burned in 2023, the most that year with the Northwest Territories a close second, despite neither the province nor territory using glyphosate on forests.

SOURCES

Claim posted to X May 12, 2026 (archived) and shared to Facebook May 14, 2026 here (archived) and May 13, 2026 here (archived)

US & Canada Fire Map. FIRMS US/Canada website. Accessed June 30, 2026 (archived)

Claim originally posted to X Aug. 20, 2025 (archived)

Glyphosate in Canada. Government of Canada website. Accessed June 30, 2026 (archived)

Briefing Note For Information. British Columbia Ministry of Forests via Government of British Columbia website. June 30, 2023 (archived)

D.G. Thompson and D.G. Pitt. Frequently Asked Questions (FAQs) On the Use of Herbicides in Canadian Forestry. Natural Resources Canada website. 2011 (archived)

Glyphosate in people living in Canada. Health Canada website. Accessed June 30, 2026 (archived)

NOTE TO READERS: This fact check was updated on July 3, 2026 to clarify that Quebec led the provinces in number of hectares burned in 2023.

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Marissa Birnie, The Canadian Press