ISA Certified Arborist or TCIA Accredited: who holds the badge

ISA certification is personal

ISA says permission to use its certification marks is "limited and personal to the certified individual" and cannot pass to a business. (ISA Ethics and Trademark Policy) So an "ISA certified company" claim points to a person on staff, not to the business.

A company with a certified employee may show the ISA logo only with that person's name and certification number next to it. "ISA Certified Arborists On Staff" is allowed once three or more certified people work there, and their names and IDs have to be listed on the website. (ISA Branding and Style Guide)

How to check an arborist

1. Ask for the arborist's full name and ISA certification ID.
2. Search either one in ISA's directory. It lists people, not companies. (ISA directory)
3. If the old Verify a Credential tool comes up in a search, skip it. ISA says that data is frozen as of July 7, 2025. (ISA FAQ)
4. Ask whether that arborist will look at your tree, or only signs off from the office.

TCIA Accreditation is for the company

TCIA describes Accreditation as "a third-party consumer confidence verification program" for tree care companies. It lasts three years, with a check-up every year. (TCIA)

Accredited companies get a separate Accreditation logo, plus truck and helmet decals. A company with several locations has to accredit each one. (TCIA FAQ)

How to check a company

1. Search the company in TCIA's accredited company finder, by name or zip code. (TCIA)
2. Look for the name on TCIA's list of companies using the Accreditation logo without the right to. (TCIA logo violators)
3. Either way, look the company up on L&I Verify. Tree removal is one of the specialties that needs L&I contractor registration, and neither badge replaces it. (L&I)

Which one matters for your job

• Inside Seattle: the City's tree registry requires at least one ISA Certified Arborist on staff or retainer, and a TRAQ qualification for hazard tree risk assessments. (City of Seattle)
• A tree you think might fail: ask for a TRAQ-qualified arborist. WA DNR says the PNW-ISA chapter database shows whether an arborist holds TRAQ. (WA DNR)
• A big removal near the house: the company's registration, bond and insurance carry the risk. An individual's certificate does not.

Next

Read what registration, the bond and insurance cover, or the questions to ask a tree service.