The milestone follows four years of wrangling between the nations, a myriad of legal cases and more than US$5bn in duties levied on Canadian softwood lumber exports by the American government.

An agreement was struck in April and the final text of the deal concluded in July, before approval by the Canadian parliament and subsequent cessation of legal challenges to the US duties.

The US-based Coalition for Fair Lumber Imports has welcomed the agreement’s implementation.

“The implementation of this agreement was achieved following difficult negotiations and significant compromises by both the US and Canada,” said coalition chairman Steve Swanson.

“The coalition hopes that this agreement will provide the mechanism by which to find a permanent solution to this unfortunate dispute between our two nations,” he added.

About US$4bn of collected duties will be returned to Canadian lumber companies, with the remainder being distributed to US lumber firms and charitable causes.

Charities benefiting include the US Endowment for Forestry and Communities (US$200m), the American Forest Foundation (US$150m) and Habitat for Humanities International (US$100m).