State Agencies
- Illinois Department of Agriculture, Emerald Ash Borer
- Illinois Department of Natural Resources, Division of Forest Resources
- Illinois Department of Natural Resources, Division of Wildlife Resources
- Illinois Department of Natural Resources, Division of Natural Heritage
- Illinois Department of Natural Resources, Urban & Community Forestry
- Illinois Department of Revenue, Woodland Assessments
- Illinois Nature Preserves Commission
- University of Illinois, Department of Natural Resources and Environmental Sciences (NRES)
- University of Illinois, Extension Forestry
- University of Illinois Extension
- University of Illinois Plant Clinic
Federal Agencies
Private Consultants/Contractors
- Illinois Consulting Foresters, Inc.
- Illinois Professional Consulting Foresters
- Illinois Arborist Association
- The Association of Consulting Foresters of America, Inc.
Illinois Forestry-Related Organizations
- Illinois Christmas Tree Association
- Illinois Arborists Association
- Illinois Consulting Foresters, Inc.
- Illinois Forestry Development Council
- Illinois Native Plant Society
- Illinois Green Industry Association
- Illinois Society of American Foresters
- Illinois Tree Farm
- Illinois Wood Products Association
- Northwest Illinois Forestry Association
Academic Institutions
- Eastern Illinois University, Department of Biological Sciences
- Western Illinois University, Department of Biology
- Illinois State University, Department of Biological Sciences
- Southern Illinois University Carbondale, Department of Forestry
- University of Illinois at Urbana-Champaign, College of Agriculture, Consumer, and Environmental Sciences (ACES)
- University of Illinois at Urbana-Champaign, Department of Natural Resources and Environmental Sciences (NRES)
Illinois Resource Conservation & Development Districts (RC&D's)
- Blackhawk Hills RC&D, Inc.
- Interstate RC&D, Inc.
- Prairie Hills RC&D, Inc.
- Prairie Rivers RC&D, Inc.
- Shawnee RC&D, Inc.
- Southwestern Illinois RC&D, Inc.
- Two Rivers RC&D, Inc.
- Illinois Association of Soil Water Conservation Districts
National Forest Landowner Associations
National Forestry Organizations of Interest
- American Chestnut Foundation
- American Forest & Paper Association
- American Forest Foundation
- American Forests
- American Society of Consulting Arborists
- Evergreen Foundation
- The Forest History Society
- Leopold Center for Sustainable Agriculture
- National Association of Conservation Districts
- National Association of State Foresters
- National Christmas Tree Association
- National Forest Foundation
- National Hardwood Lumber Association
- Northern Nut Growers Association, Inc.
- Private Forests
- Smokey Bear
- Society of American Foresters
- Sustainable Forestry Initiative
- Temperate Forest Foundation
- The Association of Consulting Foresters of America, Inc.
- The Forest Guild
- The National Arbor Day Foundation
- The Nature Conservancy
- Walnut Council
Urban & Community Forestry
- IDNR, Urban and Community Forestry
- Illinois 4-H
- Illinois Arborist Association
- International Society of Arboriculture
- Morton Arboretum
- Project Learning Tree
- The National Arbor Day Foundation
- Tree City USA
- University of Illinois Extension, Schools Online
- USDA Forest Service, Urban and Community Forestry
- Virginia Cooperative Extension Virtual 4-H