ACRT Institute of Arboriculture and Urban Forestry: Training for the line clearing, tree care and urban forestry industry.
Arboricultural Association: Promotes care and knowledge of trees in the UK. Details of activities, members, and journal.
Arboricultural Information Exchange.: The AIE site (UK) has news, links and collections of resources for arboriculture.
Arborist Site Discussion Group: A loose affiliation of volunteer tree working professionals that discuss the needs of tree care within the industry and answer questions for the general public.
Bag Snaggers: A tool for arborists and urban tree pruners for removing plastic bags and other debris from trees.
European Arboricultural Council: A forum for arboricultural organizations in Europe to liaise on research and education in tree establishment and improvement of working practices.
Great Southern Tree Conference: Educational event devoted to tree selection, landscape, production, marketing and management issues in the Southern United States. Due to take place in December 2005.
International Society of Arboriculture: Arboriculture On-line was developed to assist tree care professionals in developing and maintaining effective plant health care programs. Includes an extensive collection of urban forestry links.
Mid-Atlantic Chapter, International Society of Arboriculture: information and links on trees and their care (arboriculture); resources for arborists
National Arborist Association: The trade association of commercial tree care businesses. Site has information (for consumers and for professionals) and links on tree care practices and standards.
Shigo on Tree Systems: A set of articles by Dr. Shigo on arboriculture, and on the growth of garden trees.
The California Arborists Association: Membership information, details and timetables of activities and workshops.
Wildtrees: Includes views on conservation of native trees for the environment.