International Trade Minister Mary Ng says Canada is formally initiating a challenge of “unwarranted and unfair” U.S. duties on Canadian softwood lumber — a move that was telegraphed earlier. The Canadian government filed notice on Monday under the U.S.-Mexico-Canada trade agreement’s dispute resolution system. Ng said the duties harm Canadian businesses and workers but also serve as a tax on U.S. consumers. The U.S. cut its anti-dumping and countervailing duty rate in half earlier this month to 8.59 per cent from 17.61 per cent, but Ng signalled that Canada would still fight the measures. The crux of the U.S. argument is that the stumpage fees provinces charge for timber harvested from Crown land are akin to subsidies, since U.S. producers must instead pay market rates. Ng said that Canada is willing to work toward a negotiated solution in the long-running dispute.