There is plenty of timber in northern California and southern Oregon, these regions are actually temperate rain forests, that are harvested sustainably and aren't old growth forests. Every 30-50 years, (depending on species: redwood or doug fir) the same tracts of forest can be logged again and again.
Once you get further north the taigas are colder and slower growing and may take 200 years or longer to grow back.
The best thing for the USA is to use the resources which supports jobs in logging, wood processing, transportation, and have lower costs associated with transportation and fees from importation. I'm not against importing timber into very northern parts of the US but there is no reason to ONLY use canadian timber.
Once you get further north the taigas are colder and slower growing and may take 200 years or longer to grow back.
The best thing for the USA is to use the resources which supports jobs in logging, wood processing, transportation, and have lower costs associated with transportation and fees from importation. I'm not against importing timber into very northern parts of the US but there is no reason to ONLY use canadian timber.