Certified Arborists are trained and knowledgeable in all aspects of arboriculture. ISA Certified Arborist have met all requirements set to be eligible for the exam, this could include three or more years of full-time, eligible, practical work experience in arboriculture and/or a degree in the field of arboriculture, horticulture, landscape architecture, or forestry from a regionally accredited educational institute. This certification covers a large number of topics giving the candidates flexibility in the arboricultural profession. A code of ethics for certified arborists was implemented in June 2009 to help strengthen the credibility and reliability of the work force.

An ISA Certified Arborist who has a minimum of two years documented and verifiable electric utility vegetation management experience or have been a consultant to a utility with a minimum of 4,000 hours over a maximum 10-year period works in utility vegetation management are consider ISA Certified Arborist/ Utility Specialists. They have been tested on topics such as electric utility pruning, program management, integrated vegetation management, electrical knowledge, customer relations, and storm response.

ISA Municipal Specialists are current ISA Certified Arborists who have chosen municipal arboriculture or urban forestry as a career path. They have obtained a minimum of three additional years of documented and verifiable work experience in a position managing the establishment and maintenance of urban trees. Experience requirements include practical communication skills, public relations, administration, risk management, arboricultural practices, and policy planning in a municipal setting.

To be a Certified Tree Worker/ Climber Specialist it requires a lot of skill and endurance to be able to climb the tree, take high regards for safety, and get the job done off the ground. This credential is considered different from the other certifications because not only are you being tested in a class room setting but also hands on out in the field. Candidates provided valid proof of training in aerial rescue, CPR, and First Aid to obtain this certification.

This certification, much like the Climber Specialist, requires the ISA Certified Tree Worker/ Aerial Lift Specialist to demonstrate the fundamental skills necessary to perform as a competent aerial lift operator. The knowledge gained with this certification can improve the productivity, quality, and safety of the jobs at hand. Along with proven knowledge of CPR and First Aid training, candidates have been tested on safety procedures necessary to operate an aerial lift device and do a thorough truck and tree inspection.

ISA Board Certified Master Arborist is the highest level of Certification that is offered by ISA. It is intended to recognize Certified Arborists who have reached the pinnacle of the arboricultural profession. In addition to passing an extensive computer based exam, applicants will need to abide by a Standard of Practice which is intended to insure work quality. Less than 2% of Certified Arborists currently hold this certification.