Economic's 101.
Loonie goes down in value which make makes Canadian export more attractive.
US housing market is heavily dependent on Canadian lumber. The tariff's will hurt US consumers who will pay more as there is no alternative for Canadian lumber in the short & Mid-term. 
Net/Net. US consumer will pay more and will be worse off; Canadian economy and industries hit by the tariff's will become smarter, more productive and more competitive and will become winners.
Keep up the good work Trump with your Tariff's, we love it.