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.
Asia Tree Preservation Ltd - ATP provides arboriculture training and vegetation management consulting in the south, southeast and eastern parts of Asia.
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.
Homeowner’s Guide to Safer Trees - Copiously illustrated account of how to examine trees for safety, what symptoms to look for, evaluating the findings and information on finding an arborist. [PDF]
How to Hire an Arborist - Provides guidance on selecting a consulting arborist, who offers advice, or a full-service professional who possesses skills in planting, transplanting, pruning, fertilizing, pest management, disease diagnosis, tree removal and stump grinding.
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.
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.
Tree World - Provides an international arborist’s forum for discussion and information about trees with industry experts. Questions answered, participation for registered users.
Wildtrees - Includes views on conservation of native trees for the environment.