The softwood lumber dispute has been going on almost as long as the Jewish-Palestinian conflict with successive governments kicking the ball down the road for the next government to deal with. 
Surely there can be a final ruling under the World Trade Organization to finally resolve it if both sides agree to accept its ruling. 
Trump's solution of imposing tariffs might help American producers in the short term, but it will result in higher costs to consumers South of the border, ultimately hurting the overall economy. 
But also if the ruling is that Canadian producers are indeed getting unfair subsidies from cheap access to crown lands, they will have to learn to compete on a level playing field or be out of the game.