Columbia subject headings:
Sawmills--Canada--Maps.
Sawmills--United States--Maps.
Softwood industry--Canada--Maps.
Softwood industry--United States--Maps.
Harvard subject headings:
Sawmills--Canada--Maps.
Sawmills--United States--Maps.
Softwood industry--Canada--Maps.
Softwood industry--United States--Maps.
Princeton subject headings: