Lumber futures rose the most in more than a year on concern that wildfires in western Canada will reduce supply and spur more curtailments at sawmills.

Thousands of railcars loaded with grain are idled in the Vancouver corridor after Western Canadian wildfires damaged two main lines, while repairs enable a small but rising number to reach the country’s biggest port.

Lumber roared to a fresh record high May 3, with traders in bidding wars after the Chicago Mercantile Exchange removed limits on how high some futures prices could go.