
This July, as wildfires in Northern Ontario displaced entire communities, destroyed towns and villages and created air quality advisories in Toronto and elsewhere in Southern Ontario, Jeffrey Sun was working on telling people why it was happening.
While public health authorities advised Ontarians to stay indoors, Sun, a climate economist and Assistant Professor of Economics at the University of Toronto, was trying to get the message out through a new working paper, Wildfire Risk Durably Falls After Timber Harvests: Evidence from 40 Years of Harvest and Fire in Canada. He has long understood the urgency.
“In 2023 the carbon emissions from Canadian wildfires were roughly four times larger than the emissions from all economic activity in Canada combined,” Professor Sun said in a recent interview. “No other single source of emissions matters nearly as much in absolute terms.”
The new paper looks at what would happen if timber harvesting interests and fire prevention agencies were combined.
“There are a lot of forest fires in Canada. Yet in every province there are essentially two separate administrations: one for forest management and one for fire management,” Sun explained. “In Ontario, for example, forest management is largely carried out through long-term tenure arrangements on Crown forest lands by forest management companies or softwood lumber companies. These organizations manage the forest and harvest a sustainable amount of timber over time.”

The separation, Sun said, means that governments spend significant resources sending crews into forests to remove fuel loads, trimming trees, clearing dead wood and brush, and reducing combustible material on the forest floor. Much of that material is then burned or otherwise disposed of rather than being used to create wood fuel pellets, or other products made of ‘waste wood.’
There are historical reasons for the separation of timber harvest interests and fire prevention.
“Fire agencies were originally focused on keeping fires away from settlements and critical infrastructure,” Sun said. “But there are also institutional and trade-related factors. Any government action that appears to lower the cost of softwood lumber can trigger concerns from the American softwood lumber industry and become entangled in ongoing trade disputes.
The availability of new datasets and new methodologies rooted in machine learning enabled Sun to explore questions surrounding what a single planner, responsible for both wildfire management and timber harvesting, would accomplish.
“What if these weren’t treated as separate activities, but as part of one integrated forest-management strategy?” Sun asked. “What would the gains be? How much would wildfire risk fall? How much could emissions be reduced?”
In the paper Sun compares harvest records from the CanLaD disturbance database records from the National Burned Area Composite (NBAC) database, to estimate the harvest-fire relationship.
Sun found the timber harvests reduced the risk of wildfire. Harvested stands face a first-fire hazard that is 28% lower than comparable unharvested stands. The results suggest coordinating the timber harvest management and fire prevention could lead to substantial reductions in wildfire risk.
“The question is whether we should think about the entire forest life cycle together: growth, harvest, fire, and regeneration,” Sun said. “If we’re managing all of those processes as part of one integrated system, then decisions about where to plant, where to harvest, where to reduce fuel loads, and where to focus fire-management resources can potentially generate very large benefits relative to what we’re doing now.”
Return to the Department of Economics website.
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