Tree work license
State license required
MDAC says a Tree Surgery License is required for people who advertise (in a phone book, newspaper, newsletter, bulletin, the internet or a sign) as a licensed, bonded or insured tree surgeon and get paid for the work. MDAC also says nothing stops a person from doing this work as long as their advertising does not use the words licensed, bonded or insured. MDAC requires a certificate of liability insurance of at least $100,000 before it issues the license. Because many companies advertise that they are insured, read the MDAC page and ask the Bureau if you are unsure.
Official source