Columbia subject headings:
Forests and forestry--United States.
Timber--Grading--United States.
Wood--Defects--United States.
Wooden beams--United States.
Harvard subject headings:
Forests and forestry--United States
Timber--Grading--United States.
Wood--Defects--United States.
Wooden beams--United States.
Wooden beams.
Princeton subject headings: