The International Society of Arboriculture (ISA) is a worldwide professional organization dedicated to fostering a greater appreciation for trees and to promote research, technology and professional practice of arboriculture and urban forestry. ISA serves more than 37,000 members and credential holders worldwide.
The ISA developed and administers the Certified Arborist program the continuing education requirements necessary to remain a Certified Arborist.
Tim Gamma was president of ISA from 2009-2011, holding numerous leadership positions over the years. You can learn more about ISA and the proper care of trees at their website: ISA-arbor.cm