Tree Care Industry Association (TCIA)
http://www.treecareindustry.org - TCIA develops safety and education programs, standards of tree care practice, and management information for arboriculture firms around the world.

International Society of Arboriculture (ISA)
http://www.isa-arbor.com/ - The International Society of Arboriculture (ISA) has served the tree care industry for over eighty years as a scientific and educational organization.

Connecticut Tree Protective Association (CTPA)
http://www.ctpa.org/ - CTPA promotes the protection of Connecticut’s trees by encouraging cooperation among tree care professionals.