Short for Board Certified Master Arborist, it’s ISA’s top credential. I’ve been a Master Arborist for 6 years now. I know because every three years at this level we are required to get 60 hours of continuing education and I just certified for the third time. This much studying keeps us on top of the safest, most efficient techniques, and get more in depth on specific aspects of arboriculture that other arborists may not have been exposed to, like pathogen and risk identification or how trees and our relationship with them is affected by the law.
As of April 2012, there were 27,080 Certified Arborists and 392 Master Arborists working together against a sea of uncertified, unlicensed hacks to protect, improve, and care for our urban forest.