# ISA certification explained

Check the person, the credential and the work proposed. A directory badge is a separate matter.

Updated 2026-11-10. Also on the [web page](https://arborists.fyi/guides/isa-certification-explained).

ISA means the International Society of Arboriculture. Its Certified Arborist credential concerns a person's arboriculture knowledge. ISA describes training and knowledge across arboriculture topics and an obligation to follow its Code of Ethics. [ISA, ISA Certified Arborist, fetched 2026-11-10](https://www.isa-arbor.com/Credentials/Types-of-Credentials/ISA-Certified-Arborist).

## Ask for a named person

Ask the company who will assess your tree. Request that person's full name and ISA certification number. Use ISA's public lookup to check the record. Match the person and credential, rather than accepting a logo on a van or a business card. Save the record link with the date you checked it. [ISA, Find an Arborist, fetched 2026-11-10](https://www.treesaregood.org/findanarborist).

Ask who will write the recommendation and who will supervise the work. A company can employ people with different credentials and duties. A credential held by someone in the office does not answer who will attend your property.

## Separate the checks

Keep separate fields for the person, company, licence and insurance. Ask the local licensing authority whether it regulates your proposed work. Confirm the company's legal name and any required licence record. Ask its insurer about current cover for the proposed job. Certification is not a substitute for these checks.

If a company claims TCIA accreditation, request the accreditation record. Do not change a membership entry into an accreditation claim. Leave the accreditation field blank until you have evidence for it.

## Read the written recommendation

Ask for a plain explanation of the tree's condition and the purpose of the work. The recommendation should identify the tree and distinguish what the assessor saw from what they could not inspect. Ask what alternatives were considered and what would trigger another visit. ISA's tree owner resources include plant health care, mature tree care and risk topics. [ISA, Tree Owner Resources, fetched 2026-11-10](https://www.treesaregood.org/treeowner/choosinganarborist).

For a specialist task, ask about experience with that tree type, disease or site constraint. A general credential does not tell you whether the person has seen your exact problem before. Request relevant references and examples of written scopes.

## What an Arborists badge means

Arborists has paid Verified, Featured and Sponsored plans. These change listing features and placement. They are not an ISA credential, a licence check or a recommendation of the company. Check credentials at the issuing body, even when a listing has a paid badge.

## Sources

- International Society of Arboriculture, *ISA Certified Arborist*, fetched 2026-11-10: https://www.isa-arbor.com/Credentials/Types-of-Credentials/ISA-Certified-Arborist
- ISA, *Find an Arborist*, fetched 2026-11-10: https://www.treesaregood.org/findanarborist
- ISA, *Tree Owner Resources*, fetched 2026-11-10: https://www.treesaregood.org/treeowner/choosinganarborist

## Questions

### Does Verified mean ISA certified?

No. Arborists listing plans do not issue or confirm ISA credentials. Check the named person in the ISA record.