http://dnr.wi.gov/org/caer/ce/eek/veg/trees/treestruecolor.htm
USDA Forest Service, Northeastern Area,
http://www.na.fs.fed.us/fhp/pubs/leaves/leaves.shtm
Environmental Information Series/ESF,
http://www.esf.edu/pubprog/brochure/leaves/leaves.htm
No comments:
Post a Comment