The softwood lumber dispute reignited Friday after the U.S. Lumber Coalition said it formally petitioned the American government to impose duties against Canadian softwood lumber producers.

The lobby group said it asked the U.S. Department of Commerce and the U.S. International Trade Commission to restore the conditions of “fair trade” for softwood lumber.

The coalition alleges that provincial governments, which own most of Canada’s vast timberlands, provide trees to Canadian producers at rates far below market value, along with other subsidies. As a result, the group says Canadian lumber is being sold for less than fair value in the United States.