Amoco Oil Corporation
Arbor Day Foundation
Baxter Health Care Corporation
Carle Hospital
Caterpillar
Chamber of Commerce
Chicago Forest Preserve District
CILCO
City of Champaign, Illinois
Columbus-Cabrini Medical Center
Consolidated Edison
Cook County Administration
Dynegy-Illinova-Illinois Power Company
Feralloy Steel Corporation
Frances Nelson Health Center
Illinois League of Savings Institutions
International Society of Arboriculture
Mars Co. (Kai-Kan Division)
Merrill Lynch
Millikin University
National Arbor Day Foundation
National Cancer Institute
NUCFAC- National Urban and Community Forestry Advisory Council
Rural Partners/Kellogg Program
Sallie Mae Corporation
State of Illinois- Commerce and Community Affairs
Trees America
University of Illinois - Numerous administrative & academic departments including: UIUC Executive  Development Program & UIUC Executive Veterinary Medicine Program
U.S. Army Civil Engineering Research Laboratory
U.S. Department of Education
U.S. Forest Service
Wisconsin Power & Light
Y.M.C.A.