It follows then that the USA also wants to protect its industries, such as timber, oil and gas, and maple syrup, from Canadian producers that are happy to dump their stuff south of the border for cheaper than US competition.
> […] from Canadian producers that are happy to dump their stuff south of the border for cheaper than US competition.
The USD and CAD are not 1:1, as the CAD is 'lower value', so of course stuff made in Canada will generally be less expensive. (The trade off is that imports are more expensive for Canadians.)
The US sets the price it pays for Canadian oil, a discount from the market price.
I don't know about timber, but the US maple syrup industry is healthy, just unable to keep up with demand. I think that's a consequence of geography and the time investment required to get mature trees, not Canada undercutting.