More Tree Info
American Forests is a national advocacy group that focuses on public policy issues affecting trees and forests.
Massachusetts Arborists Association.
Massachusetts Nursery and Landscape Associates.
New England Grows - an annual event.
A web site that lists other tree reference sites
BOOKS:
A Field Guide to Trees and Shrubs, George Petrides, Houghton Mifflin, 1972, ISBN 0395136512
A Field Guide to Eastern Trees: Eastern United States and Canada (Peterson Field Guide Series) by George A. Petrides, ASIN: 0395467314
The Illustrated Book of Trees: The Comprehensive Field Guide to More Than 250 Trees of Eastern North America by William Carey Grimm, et al , ISBN: 0811728110 (Paperback - June 2001)