Mode of access: Internet via the USDA Forest Service web site. Address as of 08/28/08: http://www.fs.fed.us/pnw/pubs/gtr590.pdf; current access available via PURL.
Note
Title from title screen (viewed on Aug. 28, 2008).
"Based on a 1998 final report for the USDA-FS Northern Region Air Program."