A few points to keep in mind:
1. The US private timber owners will never be enthused by large volumes of Canadian lumber flowing into the US when prices are depressed by lack of demand. Things have changed however. The industry in BC is no longer required to cut to protect jobs in order to keep their forest tenures.
2. The pine beetle kill in BC is precipitating a shortage of timber which will eventually cause the closure of more BC mills.
3. Given this shortage BC's forest industry is buying mills in the US. Margins are much higher there and output from these southern mills is providing over 20% of the lumber in the US market.
4. The new President of the US is not politically beholden to the US lumber lobby and will probably make a decision based on the effect import duties would have on home construction prices. It is possible, though, that he will open federal lands to logging that have heretofore been closed to that activity to increase domestic timber supply.