I don't have source references, other than common knowledge of someone who lives in the part of the U.S. that produces more lumber than anywhere else in the country (western Oregon). Here goes, FWIW.
I guess I can see how someone mught think alot of wood comes from China, if they shop in the DIY Big Box stores (HD, Lowes, etc.). Lately those places have been carrying hardwood plywood from China, as good-quality cabinet-grade plywood produced in North America is generally too expensive for the DIY market.
But as for softwood (construction) lumber, almost all of it comes from U.S. or Canada. British Columbia produces alot of lumber, just as Oregon and Washington. Almost all of the top-grade Western Red Cedar use for siding comes from British Columbia.
The other big producing region in North America for construction lumber is the Southeast. Constructiom lumber on the East is typically Southern Yellow Pine (SYP); on the west coast it's Douglas Fir (DF) from the Pacific NW.
Construction lumber all comes with a grade stamp identifying the mill, so it should be possible to identify the source.
Hardwood (furniture) lumber production is more spread out throughout the country, although the hardwood forests in the east (e.g., Pennsylvania) are well-known. AFAIK little of it comes from outside the country as raw lumber.
