US President Donald Trump signed an order on Friday removing 50% tariffs on several Canadian agricultural and forestry products. The move could benefit businesses in Maine, where Republican Senator Susan Collins faces a closely contested re-election race.

Trump’s tariffs on Canada have strained trade relations and created challenges for American businesses that depend on Canadian goods. Collins had urged the White House to address tariffs affecting Maine’s companies and farmers.

The White House said the exemptions cover plywood sheets, certain paper products, machinery, refrigeration equipment, packing crates, boxes, and fresh and dried seaweed. The changes will take effect on October 30, four days before the election.

However, Trump added several Canadian products to the 50% tariff list, including carpets, paints, shampoos, cocoa powder, wooden coffins, air-conditioning machines, chest freezers, canoes and archery equipment.

Collins said the relief would support Maine’s blueberry, potato, apple and seaweed producers. "These producers are a vital part of our state's economy and support our rural and coastal communities," Collins said. "Many of our farmers and growers rely on specialised equipment, packaging materials and other products from Canada that are either unavailable from American suppliers or cannot be replaced without incurring significant expense."

Democrat Troy Jackson, who is challenging Collins, criticised the move. "Trump's trade wars have made life harder and more expensive for Mainers," Jackson said on Friday after Trump's action. "Susan Collins enabled this chaos, voted to confirm the people behind it and now wants credit for bringing a cup of water to put out the fire."

Trump imposed 50% tariffs on $20 billion worth of Canadian imports in August after trade talks collapsed. Canada retaliated in September with tariffs ranging from 15% to 50% on $20 billion worth of US goods. Trump said on Friday that Canada was working towards a deal.

White House spokesperson Matthew Middleton said Trump "continues to address Canada's discriminatory treatment of US commerce" and described the changes as "further refining the scope" of the existing tariffs.

Canadian Trade Minister Dominic LeBlanc said Ottawa was assessing the latest changes. "Canada stands ready to work constructively and in good faith towards a more mutually beneficial trading relationship that respects Canada's interests," LeBlanc said.

Republicans in border states such as Maine and Michigan face pressure to retain conservative support while attracting independent voters. Both states have strong economic ties with Canada, and closely contested Senate races could determine the Republicans’ narrow majority.

Senator Ron Wyden, the top Democrat on the Senate Finance Committee, accused Trump of trying to rescue Collins politically. Meanwhile, Republican Michigan Senate candidate Mike Rogers praised Trump’s tariffs on Canadian waste.

Trump also withdrew a threatened ban on Canadian aircraft maker Bombardier this week following appeals from Kansas lawmakers. The company employs 1,500 workers in Wichita, making the issue politically significant in the state.