Question

how much of the united states and canada is covered in timber reserves

Answer 1

Please define exactly what you mean by "timber reserves." Are these areas owned by governmental bodies and/or private companies? There are different laws for them as well as for national forests and parks and state/provincial forests, parks.

Answer 2

http://www.google.com/search?hl=en&as_q=timber+reserves+canada+%22united+states%22&as_epq=&as_oq=&as_eq=&num=10&lr=&as_filetype=&ft=i&as_sitesearch=&as_qdr=all&as_rights=&as_occt=any&cr=&as_nlo=&as_nhi=&safe=images
and
http://www.google.com/search?hl=en&client=firefox-a&rls=org.mozilla%3Aen-US%3Aofficial&hs=LT6&q=canada+government+forest+reserves&btnG=Search

I'm not sure there's an actual number that anyone knows of. You might search at www.fedstats.gov for US information.