The early winners in President Trump’s trade wars are finding that victory can be bittersweet. Unlike many American corporations, companies in industries like steel, aluminum, lumber and home appliances asked Mr. Trump to raise tariffs. These businesses… had long complained of unfair foreign competition. …Executives who support the Trump administration’s tariffs say they now have the confidence to expand. …One such business is Westervelt, based in Tuscaloosa, Ala., which plans to spend $190 million to build a lumber mill in Thomasville, Ala. Joe Patton said the company had decided to invest in the mill, because the administration imposed duties on Canadian lumber in 2017. …His company is not alone. Other lumber businesses are expanding across the Southern pine lands. …Mr. Patton said he still expected Westervelt’s lumber business to prosper over the next five to 10 years. But the decline in lumber prices will eat into profit margins.