A decades-long UBC study reveals that clear-cutting doesn’t just increase flooding — it can multiply extreme events up to 18 times and make them more than twice as large.
Clear-Cutting Linked to Surge in Catastrophic Floods
Clear-cutting can dramatically intensify flood risks, making the most severe events up to 18 times more frequent and leaving impacts that last more than four decades, according to new research from the University of British Columbia.
In one watershed, the scale of these extreme floods more than doubled, turning what was once a rare, once-in-70-years event into something that now occurs roughly every nine years.
“This research challenges conventional thinking about forest management’s impact on flooding,” said senior author Dr. Younes Alila, a hydrologist in the UBC faculty of forestry. “We hope the industry and policymakers will take note of the findings, which show that it matters not only how much forest you remove but also where, how and under what conditions.”
By University of British Columbia — August 12, 2025
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