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Licensed, certified, accredited, insured: what each word means for a tree owner

Tree companies describe themselves with four different words, and each one comes from a different kind of body. This page sets out what the licensing offices, trade bodies and consumer offices say each word covers.

This page is for tree owners. It reports what the named sources say and is not advice about your tree: for that, ask a qualified arborist or one of the offices under Who to call.

Checked against the sources at the bottom of this page on October 9, 2026. Rules, fees and pay change: the source has the last word.

This page reports what the official source says. It is not legal advice: ask the office named here. Rules differ by state, province and country, and a trade body describes only its own scheme.

Certified

The International Society of Arboriculture (ISA) TreesAreGood page calls an ISA arborist certification a nongovernmental, voluntary process by which individuals document their base of knowledge. The ISA false advertisements page says ISA credentials are earned by individuals, never by a company. On ISA's wording, the credential belongs to a person and not to a company. The ISA Tree Risk Assessment Qualification is a separate voluntary qualification, described on the ISA TRAQ page, and it must be retrained and retested every seven years.

Licensed

A licence comes from a government office, and whether one exists depends on the place. The Maryland Department of Natural Resources licensed tree experts page says all tree care professionals practicing in Maryland must obtain a licence, and that without one they may not practice or advertise tree care services in the state. The California Contractors State License Board lists a tree service contractor classification, D-49, which covers pruning trees, removing trees, limbs or stumps including grinding, and guying. In Georgia, the state Attorney General's storm scam warning says certain specialty occupations, including tree removal services, are not required to be licensed by the state. The guide on which US states license arborists lists the rest.

Accredited or approved

Accreditation is awarded to a business by a trade body. The Tree Care Industry Association (TCIA) page Hiring a Tree Care Company calls its accreditation a voluntary program for companies meeting criteria for professionalism, employee training, safety regulations, business ethics and customer satisfaction. In the United Kingdom the Arboricultural Association page Choosing your Arborist says businesses on its ARB Approved Contractor Directory are assessed on health and safety procedures, business practices and quality of tree work, and that a business not on the online register is not an Approved Contractor. The New Zealand Arboricultural Association runs an Approved Contractor Programme, described on its Why Hire An Arborist page, and a Registered Master Arborist list, described on its find an arborist page.

Insured

Insurance comes from an insurer, and the sources name different kinds. The Arboricultural Association names public liability and, where there are employees, employers' liability. The NZ Arb page Why Hire An Arborist names personal and property damage insurance and professional indemnity insurance, and says to phone the insurer if proof leaves doubt. TCIA names certificates of liability and workers' compensation insurance. The Tennessee Attorney General's tree services alert says to ask for proof that the policy covers tree services whether or not the contractor is licensed, and says an executive order suspending the licence requirement after a storm did not provide contractors with insurance. The TCIA page adds that if a tree care company has no insurance or is not a legal company, the homeowner could be held responsible as a contractor; that is TCIA's statement, and this page does not say how it applies in any state.

The four words side by side

WordComes fromHeld by
CertifiedA professional body such as ISAA person
LicensedA government office, where one existsA person or business, as the office sets
Accredited or approvedA trade bodyA business
InsuredAn insurerA business or a person

The guide on insurance cover for tree businesses describes the covers themselves, and checking a tree company lists the public lookups.

Who to call

Sources