A number of key players made late decisions to back the deal in time to meet an August 21 deadline set by Canadian international trade minister David Emerson.

The endorsement of the British Columbia provincial government, West Fraser Timber, Tolko Industries and Coast Forest Products Association followed an 11th hour concession by the US government.

Media reports suggest the US has pledged not to break the agreement except in extreme circumstances, while a bi-national panel would examine the status of lumber felled from privately-owned land, which had been a sticking point with several Canadian producers.

West Fraser Timber, Canada’s second largest softwood producer, said it had “reservations” about the deal.

“The government of Canada has advised us that this agreement is the best that can be achieved at this time and, although it falls short of what we had hoped for, we believe that, on balance, our interests are best served by participating in its implementation,” said West Fraser president and CEO Hank Ketcham.

The US and Canadian governments agreed the text of the deal on July 1 in order to end the long-running dispute. The US plans to hand back more than C$4bn in duties collected from Canadian lumber companies, who are expected to drop their legal actions against the American government.