An arborist by definition is an individual who is trained in the art and science of plants, caring for and maintaining individual trees. ISA Arborist Certification is a non-governmental, voluntary process by which individuals can document their base of knowledge. It operates without mandate of law and is an internal, self-regulating device administered by the International Society of Arboriculture. Certification provides a measurable assessment of an individual’s knowledge and competence required to provide proper tree care. Certified arborists are individuals who have achieved a level of knowledge in the art and science of tree care through at least three years experience and have passed a comprehensive examination developed by some of the nation’s leading experts on tree care. Certified arborists must also continue their education to maintain their certification. Therefore, they should be up-to-date on the latest techniques in arboriculture.