The volume of Canadian softwoods exported to the US plunged by more than 25% in the weeks after the US duties took effect.

A federal monitoring programme, set up last year after US lumber producers filed countervailing and anti-dumping complaints, says exports from British Columbia, which accounts for about half the cross border lumber trade, fell nearly 18% over the same period last year.

Quebec’s exports plunged by a massive 49% and Ontario’s shipments dropped 45%.