Tree Surgeon Accreditations Explained (ARB Approved, TrustMark, NPTC and More)
Tree surgeon websites are covered in logos. Some mean a lot. Some mean very little. This guide sorts them into three groups. Some badges mean the firm was inspected. Some mean a person passed a test. Some are just a membership or a listing.
Quick comparison
| Badge | Who gives it | What it checks | How to verify |
|---|---|---|---|
| ARB Approved Contractor | Arboricultural Association | The whole business: tree work, safety, insurance, office practice. Reassessed regularly. | Search the register |
| TrustMark | Government-endorsed scheme | Business has been vetted to required standards and committed to customer service. | TrustMark site |
| Which? Trusted Trader | Which? | Business assessed and endorsed by Which?; customer reviews collected. | Which? Trusted Traders |
| NPTC / City & Guilds | Awarding bodies | An individual passed a practical test (for example chainsaw use, climbing, rescue). | Ask to see the certificate |
| Lantra | Awarding body | An individual completed training or a test. | Ask to see the certificate |
| ISA Certified Arborist | International Society of Arboriculture | An individual passed a knowledge exam and keeps up training. | Ask for the certificate number |
| CHAS / SSIP / Constructionline | Safety schemes | Business paperwork on health and safety. Mostly used to win commercial contracts. | Ask for the certificate |
| Arboricultural Association member | Arboricultural Association | A paid membership. Not an inspection. | Ask; do not confuse with Approved Contractor |
| Checkatrade / TrustATrader / MyBuilder | Directories | Listing plus reviews. Some check insurance and ID. | Read the profile |
Group 1: Badges that inspect the business
ARB Approved Contractor
This is the top badge. The Arboricultural Association says approved firms "have submitted their businesses and their tree work to the Arboricultural Association for assessment and have been found competent". It checks four things: how well they know and apply current tree work practice, whether they follow the law, whether they follow health and safety rules, and how well they run the office and look after clients. (Why should I use an ARB Approved Contractor?)
Approved firms must hold at least £5 million public liability insurance, with a maximum excess of £250 per incident, plus employers' liability and professional indemnity where relevant. (Same source.)
The register is public. The Association is blunt: "if they do not appear on the online register then they are not an Approved Contractor." (Directory)
In our directory, Thor's Trees, Artemis Tree Services and A1 Town & Country say they hold this status. Confirm it on the register before you rely on it.
TrustMark
TrustMark describes itself as "the Government Endorsed Quality Scheme". Choosing a registered business means "engaging with an organisation that has been thoroughly vetted to meet required standards and has made a commitment to good customer service". (What is TrustMark) It is a general home-improvement scheme, not a tree-specific one. Thor's Trees and Artemis say they are TrustMark registered.
Which? Trusted Trader
Which? assesses businesses and then displays customer reviews on its own site. Profiles we checked show a star rating, a review count and the phrase "Endorsed by Which?". Clear Cut Trees (4.9 from 53 reviews) and Twisted Tree Surgery (5.0 from 39 reviews) had live profiles when we checked on 5 September 2026. (Clear Cut Trees profile, Twisted Tree Surgery profile)
Group 2: Badges that test the person
NPTC, City & Guilds and Lantra
These are the certificates a tree surgeon earns for specific skills. Examples: chainsaw maintenance and cross-cutting, felling small trees, tree climbing and aerial rescue, using a chainsaw from a rope and harness. The certificate belongs to the person, not the firm.
Two questions to ask:
- Does everyone on the crew hold the units for the work they will do?
- Can I see the cards or certificates?
TrustATrader profiles sometimes list the exact units a firm has shown them. Trees A Crowd's profile, for example, lists chainsaw, climbing and rescue, felling, first aid and tree survey certificates. (TrustATrader profile)
ISA Certified Arborist
This is an international knowledge exam. It shows the person understands tree biology and care, not just cutting. LG Trees says its lead arborist has held it since 2013. (LG Trees)
Group 3: Memberships and listings
Arboricultural Association membership
A firm can join the Association as a member. That is different from being an Approved Contractor. Tree Matters, Clear Cut Trees and M. Parkin Tree Specialists describe themselves as members. That is a positive sign of engagement with the trade. It is not an inspection.
CHAS, SSIP, Constructionline
These schemes check health and safety paperwork. Firms use them to bid for council or commercial work. For a home job they are a plus. They do not replace insurance and skill certificates.
Directory listings
Checkatrade, TrustATrader, MyBuilder and Yell are directories. Some check insurance and company details. TrustATrader profiles we saw named the insurer and gave an "insurance verified through" date. That is useful. But a listing is not an inspection of tree work.
What a good North London firm looks like
- Public liability insurance of at least £5 million, shown on request
- Every climber and chainsaw user holds the right NPTC, City & Guilds or Lantra units
- Ideally, ARB Approved Contractor status, confirmed on the register
- A real address and a company number you can check at Companies House
- Reviews on at least one independent platform
Frequently asked questions
Is "fully qualified" a real qualification?
No. It is a phrase, not a badge. Ask which certificates the crew holds and who issued them.
Is an Arboricultural Association member the same as ARB Approved?
No. Membership is a subscription. Approved Contractor status is an inspection of the business and its work.
Does TrustMark check tree work?
TrustMark vets the business and its customer service. It does not inspect tree work in the way the Arboricultural Association does.