A new 50% tariff on Canadian goods takes effect August 19, 2026, and it carves out the one product category that has defined the US-Canada trade relationship for four decades: raw softwood lumber. Plywood, particleboard, fiberboard and other panel products got no such exemption. For lumber dealers, mills and specifiers working across both sides of the border, the result is a more complicated compliance map, not a simpler one, and it lands two days before this article publishes, with a parallel Commerce Department duty review still unresolved.
A carve-out that is not relief
The tariff, proclaimed under Section 338 of the Tariff Act of 1930, responds to what the administration calls discriminatory Canadian trade practices on autos, dairy and alcohol. It covers roughly $20 billion in Canadian imports across three proclamations and applies even to goods that would normally move duty-free under the US-Mexico-Canada Agreement (USMCA), which Canada refers to domestically as CUSMA. Raw timber and softwood lumber are excluded because they already carry a 10% tariff imposed under Section 232 of the Trade Expansion Act of 1962, which took effect October 14, 2025, and the proclamations exempt products already subject to Section 232 action from the new 50% rate.
That exclusion does not extend to processed wood products. Roughly 98 Canadian forest-product tariff lines are subject to the new 50% duty, including plywood, particleboard, medium-density fiberboard, veneered panels, wood moldings, doors, picture frames and pulpwood, along with a range of wood-derived paper goods. The Forest Products Association of Canada called the move “a direct assault on our sector and on our workers.” Ontario Forest Industries Association president Ian Dunn said the timing compounds a record wildfire season in the province and threatens to “shatter” trade stability. United Steelworkers national director Marty Warren described the broader tariff package as economic coercion unrelated to fair trade practice, and Canadian Prime Minister Mark Carney called the action one-sided and inconsistent with existing trade commitments.
The duty review nobody has finished
Underneath the new tariff, the US Department of Commerce is still working through the seventh administrative review of the antidumping and countervailing duty orders on Canadian softwood lumber, covering shipments from January 1 through December 31, 2024. Commerce published preliminary results on April 14, 2026. The preliminary antidumping margins ran from 4.77% for West Fraser Mills to 16.85% for Canfor, with non-examined companies assigned 10.66%. Preliminary countervailing rates ran from 11.70% for Resolute FP Canada to 15.93% for West Fraser, with 215 non-selected companies, including Canfor, assigned 14.17%. Combined, the preliminary rates range from 20.70% for West Fraser to 31.02% for Canfor, with most Canadian producers landing at the non-selected combined rate of 24.83%.
Commerce revised the countervailing figures again in a post-preliminary analysis published June 30, 2026, pushing some company rates higher, with Canfor at 14.52%, Resolute at 12.24% and West Fraser at 16.15%, and combined rates for named respondents reaching as high as 31.37%. Commerce’s own regulations call for final results within 120 days of the April preliminary notice, a deadline that fell around August 12, 2026. As of this writing, Commerce had not yet published final results in the Federal Register, leaving cash deposit rates for the review period technically still preliminary and subject to revision once the final determination lands.
Negotiations stalled, lumber sidelined
Canadian Trade Minister Dominic LeBlanc and chief negotiator Janice Charette met repeatedly with US Trade Representative Jamieson Greer in Washington this month, and LeBlanc said as recently as August 17, 2026 that the two countries remain far from a draft agreement. The sticking points are dairy market access and the return of American alcohol to provincial shelves in eight of ten provinces, not lumber. US officials have signaled they view the softwood dispute as a preexisting matter outside the scope of the current talks, meaning even a broader tariff deal on autos, dairy and alcohol would likely leave the antidumping and countervailing duties, the Section 232 lumber tariff and the new Section 338 panel tariff untouched.
What the layered duties are doing to cost
The compounding effect is the story for anyone specifying or importing wood products. Raw softwood lumber currently carries the preliminary combined antidumping and countervailing rate of roughly 25% to 31% depending on producer, plus the 10% Section 232 tariff, for an effective burden approaching 35% to 41% before freight and currency effects. The US Lumber Coalition, which supports the duties, argues they have worked as intended, saying enforcement has cut Canada’s share of the US lumber market from 35% to an average of 19%. The National Association of Home Builders estimates the combined tariffs and duties have added at least $10,000 to the cost of a new single-family home. Canada’s federal government has responded with domestic support measures for affected mills, including workforce training programs and a potential C$1.5 billion loan package through the Business Development Bank of Canada.
What to watch
Three dates matter most for procurement and compliance teams over the next several weeks. First, Commerce’s overdue final results on the seventh administrative review, which will set binding cash deposit rates for softwood lumber shipments from Canadian mills and could move materially from the preliminary 20.70% to 31.02% range. Second, the effective date of the Section 338 tariffs on August 19, 2026, which importers of Canadian plywood, particleboard, fiberboard and other panel products should confirm against their own tariff classifications now, since the carve-out for Section 232 goods does not automatically extend to every wood-derived product. Third, the pace of the LeBlanc-Greer talks, which could produce relief on autos, dairy or alcohol without touching lumber at all. Specifiers and buyers sourcing Canadian panel products should model the new 50% duty into near-term bids immediately, and mills and distributors on both sides of the border should treat the current 24.83% to 31.37% duty range as provisional rather than final until Commerce publishes its determination.