U.S. President Donald Trump is threatening new tariffs on Canada over forest fire smoke that, he said, has “invaded” American cities in recent days, calling it “Willful Negligence” on the part of Canadian authorities.
Mr. Trump, in a post to his Truth Social site on Friday, said the smoke has created an “incalculable” expense for the U.S., and the “cost of this pollution must of necessity be added to the TARIFFS Canada is currently paying.”
The U.S. President said he would call Prime Minister Mark Carney on Friday to discuss the issue, and made no concrete proposal for what tariffs, if any, he could apply. The U.S. Supreme Court, in a ruling earlier this year, constrained Mr. Trump from summarily imposing tariffs on an emergency basis.
“We are holding Canada responsible for the fact that they are not properly maintaining their Forests, and Brush therein, and the United States is being unnecessarily invaded by filthy, polluted, and unhealthy air, the quality of which is dangerous, and totally unacceptable!” Mr. Trump wrote.
Earlier this week, a group of Michigan Republican leaders wrote Mr. Carney to complain about the smoke, faulting Canada for “chronic under-investment in forest thinning, fuel reduction, and prescribed burns, along with inadequate enforcement against arson.”
The letter threatened “direct involvement” by U.S. agencies in “cross-border fuel reduction and firefighting capacity” – without explaining what that might mean.
Pete Hoekstra, the U.S. Ambassador to Canada, had offered a more conciliatory tone in a statement Wednesday, noting that” Canadians living near these fires are already facing hazardous air quality” and pledging to continue a lengthy history of jointly fighting wildfire.
“This challenge knows no borders,” Mr. Hoekstra said in the statement. “The United States will continue to coordinate closely with Canada, just as we have for more than four decades of shared wildfire emergencies.”
In a statement posted to social media, Eleanor Olszewski, the federal minister of emergency management and community resilience, said Canada and the United States are continuing to work together to fight wildfires on both sides of the border based on an agreements signed in 1982 and at the G7 meeting in Alberta in 2025.
“As part of this work, both countries remain in constant contact about the evolving wildfire situation,” she wrote.
Her post did not say whether Mr. Trump and Mr. Carney had spoken. Nor did it address criticism that Canadian forest policies did not include aggressive efforts to clear fuel from its vast forests.
Ontario has counted nearly 200 active wildfires this year, which together have already consumed vast swaths of forest. In a news conference Friday, Ontario Premier Doug Ford said he had spoken with the governors of Massachusetts and Minnesota. He asked for water bombers from Massachusetts, but was told none were available.
”I asked for firefighters, anything that they can send,” Mr. Ford said.
Canadian police and military have already helped to rescue stranded American campers in response to a request from Minnesota Gov. Tim Walz, he said. And Canadian resources are regularly offered to help respond to emergencies in the U.S., including linemen who helped to restore power in Georgia and North Carolina in the fall of 2024.
”If there’s some politicians out there chirping away, well, maybe what you should do rather than complain is send support. Send help,” Mr. Ford said. “Because we have done the exact same thing for our American friends. And that’s what you’re supposed to do.”
Mr. Trump has for years spoken out about forest practices, often directing criticism toward California Democrats. In 2018, he said the state should adopt what he described as the Finnish practice of “raking and cleaning” forests – a statement disputed by Finland’s president at the time, Sauli Niinistö.
In 2020, Mr. Trump again suggested California’s wildfires were the result of insufficient effort to scrub the state’s woodlands.
“You gotta clean your floors, you gotta clean your forests – there are many, many years of leaves and broken trees and they’re like, like, so flammable, you touch them and it goes up,” Mr. Trump said at the time.
California’s forest stretches over 133,000 square kilometres, an area nearly twice the size of New Brunswick.
In Canada, the boreal forest reaches across 5.5 million square kilometres, much of it sparsely populated and with few access roads. In recent years, however, fires have burned through staggering tracts of the Canadian woods, consuming fully eight per cent of the country’s forest in the past three years alone.
The Canadian Chamber of Commerce declined to comment on Mr. Trump’s threat to respond with additional tariffs. The Prime Minister’s Office did not immediately respond to a request for comment about whether Mr. Carney had spoken with the U.S. leader.
Climate activists, however, have ridiculed Mr. Trump’s suggestions that Canada could do more to tidy its trees, saying the sole practical solution lies in reducing emissions that raise global temperatures.
“The boreal forest is the largest biome on earth. Saying someone should ‘manage’ it is the equivalent of King Canute commanding the tide to stay out,” said Keith Stewart, senior energy strategist for Greenpeace Canada. “The only thing we can do is switch to stop burning the fossil fuels that are warming the planet and creating the hotter, drier conditions that fuel wildfires.”