What is a Board Certified Master Arborist?
Board Certified Master Arborist explained
ISA Board Certified Master Arborist® (BCMA) is the highest-level credential the International Society of Arboriculture offers. A candidate must have a strong knowledge base across multiple realms of the industry such as tree health care, tree biology, tree protection during construction, tree pruning, planting and removal, and the list goes on.
Qualifying candidates then sit a 165-question, 4-hour, scenario-based exam and require 70% to pass. Fewer than 2% of all Certified Arborists go on to hold this credential.
When you see a Board Certified Master Arborist credit on a listing here, it’s because we found that specific person by name in ISA’s own public arborist directory.
Benefits of a Board Certified Master Arborist
It’s broader as well as deeper. The exam covers not just tree science and technique but risk assessment, appraisal, and how a tree-care operation is actually run — not just what a good pruning cut looks like.
It’s rare. With under 2% of Certified Arborists holding one, it reflects years of additional education, credentials, and experience layered on top of the base certification.
It’s often the right person for a second opinion. Because the exam specifically covers risk assessment and appraisal, a BCMA is usually who you’d want for a dispute, a second opinion, or a report that needs to hold up with a municipality or in a legal proceeding.
Anyone can access this arborist directory through ISA’s website www.treesaregood.org to see a complete list of every Certified Arborist and Board Certified Master Arborist.
Limitations of a Board Certified Master Arborist
It’s still not a license. ISA’s own program guide states plainly that none of its certifications represent licensure, registration, or authorization to conduct business. Ontario has no licensing system for arborists either way.
It doesn’t cover a company’s business practices directly. The exam includes a management domain, but holding a BCMA says nothing about a specific company’s insurance, WSIB standing, pricing, or day-to-day safety record — check those separately.
One way to think of it: a Certified Arborist is like a general practitioner for trees, and a Board Certified Master Arborist is like a really good general practitioner. Being a BCMA doesn’t guarantee the credential holder specializes in the particular area a client’s concern falls under.
It’s strictly a multiple-choice test, not a hands-on one, so it can’t attest to a credential holder’s hands-on skillset.
It’s a standardized international exam, so it doesn’t test the regulations, tree species, or pest concerns unique to any one region. It’s not correct to assume a Board Certified Master Arborist is familiar with local or site-specific concerns just because they hold the credential.
It’s rare enough that its absence isn’t a red flag. Because so few arborists hold this credential, most legitimate, competent tree service companies in Ontario simply won’t have one on staff.
It’s one person’s credential, not the company’s. As with a Certified Arborist, it’s worth confirming specifically who on a job will be the BCMA, since it likely won’t be everyone working on your property.