Serious doubts about the deal succeeding have been expressed by both its critics and supporters, including Canadian international trade minister David Emerson, who admitted there was not sufficient “buy-in from industry”.

The final text of the agreement was agreed by the US and Canadian governments on July 1 and was hailed as the end of the softwood lumber war.

But several key Canadian lumber producers, including West Fraser and Interfor, have come out against the deal. Even supporters such as Canfor believe more work is needed for the agreement to become a reality.

Critics have spoken against the agreement’s termination clause, which can be exercised after 23 months, plus the taxing of value-added timber.

The deal would see the US return C$4bn in duties to Canadian lumber companies in exchange for legal action being dropped. To succeed, the deal needs support from 95% of companies in line to receive money.

Meanwhile, uncertainty has also grown due to a ruling by the US Court of International Trade, which disagreed with the American lumber lobby’s main contention – that Canadian softwood lumber imports are unfairly subsidised. The US government is considering an appeal.