A certified arborist is a tree-care professional (arborist) who not only has several years experience in the field, but has undergone stringent testing on all aspects of arboriculture. Certified arborists must demonstrate a knowledge of a vast array of tree-care concepts such as identification, tree and soil nutrition, cabling, pruning, bracing , understanding how to treat disease and damage as well as understanding safe climbing and overall safe work practices. Certified arborists must adhere to a Code of Ethics and maintain their certification through continued education and testing.
For more information, you can find out more about ISA’s mission or read the certified arborist wiki page.