A consumer's guide to arborist qualifications

Tree surgeons' qualifications

This brief introduction to some of the more common qualifications for tree surgeons in the UK should help give you some idea of the level of skill of people you're considering employing.


Accreditation of companies

Two schemes provide ongoing assessment of both the technical competence and business practices of tree surgery companies. These are

  • Arboricultural Association Approved Contractors
  • Trustmark Registered companies

You can find more information about these schemes on our accreditation pages. Companies accredited under these schemes can be found through our post code search facility.

Arboricultural qualifications

These qualifications indicate a level of technical knowledge of tree care and arboriculture in addition to the practical skills necessary to carry out tree surgery safely. Throughout these descriptions reference is made to the Qualifications and Credit Framework (QCF). You can find out more about the QCF here.

RFS Cert Arb

To obtain the Royal Forestry Society Certificate in Arboriculture a candidate must obtain a range of NPTC certificates in various practical competencies (see NPTC below) and pass a theoretical exam. The RFS Cert Arb was equivalent to a QCF level 2 qualification and was often studied for on a day release or self study basis. It indicates a considerable level of practical competence underpinned by technical understanding.

ISA Certified Arborist

International Society of Arboriculture Certified Arborists have a level of technical knowledge equivalent to about QCF level 2. The ISA Certified Arborist scheme differs from other qualifications in that it requires certified arborists to undertake ongoing education to keep their knowledge and certification up to date.

City and Guilds Phase II

The City and Guilds Phase II Certificate in Arboriculture is often studied on a block release or part time basis. The exam and assessments test both practical skills and underlying technical knowledge. It is equivalent to QCF level 2 - 3.

AA Tech Cert

The Arboricultural Association Technician's Certificate (now administered by ABC Awards) is an intermediate level qualification aimed at supervisors, tree inspectors and technicians. It demonstrates significant technical knowledge and understanding. The AA Tech Cert was equivalent to a QCF level 4 qualification and was often studied for on a day release or self study basis. It is being replaced by the QCF Level 4 Certificate and Diploma.

NC(Arb) / ND (Arb)

The National Certificate and National Diploma are two or three year full time course imparting both practical skills and technical knowledge. They lead to a qualification equivalnent to QCF level 3.


The Higher National Certificate and Higher National Diploma are two to three year full time courses with a more technical bias. The HNC is equivalent to QCF level 4 qualification and the HND is at QCF level 5. The HND has now been largely replaced by the Foundation Degree.


The Royal Forestry Society Professional Diploma is a high level technical qualification indicating considerable technical knowledge in a wide range of areas. The PD Arb is often studied for on a day release or self study basis. It is a QCF level 6 qualification and is now administered by ABC Awards. The PD Arb has been known by several other names in the past, including M Arb and (confusingly) ND Arb. It is being replaced by the Level 6 Diploma in Arboriculture.


Practical competencies

These qualifications assess practical, craft level competence.


The National Proficiency Tests Council issues certificates of competency in a range of practical skills, attesting the holders ability to carry out tasks in a safe and proficient fashion. Most important of these to the arborist or tree surgeon are certificates of competence in the use of chainsaws. You should not employ anyone using a chainsaw who does not hold the relevant NPTC certificate.

Other areas tested by the NPTC include tree climbing, aerial rescue and the use of chippers and stump grinders.

General accreditation

ISO 9001

ISO 9001 is an international standard for Quality Management Systems. Companies which are ISO 9001 accredited will have had their business processes audited by an independant assessor

ISO 14001

ISO 14001 is an international standard for environmental management systems. It requires a company to take a systematic approach to minimising its environmental impact.


The Contractors Health and Safety Assessment Scheme (CHAS) is a scheme that assesses the health and safety policy and practices of many types of contractor. Many arboricultural contractors are registered through the CHAS scheme. Registration indicates evidence of good health and safety pracitce, but does not itself indicate competence in the technical skills of arboriculture.


Council approved

The words "Council approved" often appear in adverts for tree sugeons. Unfortunately, there is no clear standard for what this means. Sometimes it may mean that a council employs that company to carry out work for them. Some councils produce lists of tree surgeons that they have assessed in some way as being competent. Increasingly councils do not have resources to assess tree surgeons and where they do produce a list it is nothing more than a list, with no implied approval or recommendation. You should ask the company claiming to be "Council approved" which council it is that approves them, and then check with the council just what is meant.

All work to BS3998

This is another claim you may see on adverts. BS3998 is the British Standard "Recommendations for Tree Work". All good tree surgeons will carry out work to BS3998, and you should certainly check with any company you are thinking of employing that they are familiar with the standard and work to it. However, simply claiming that work will conform to BS3998 does not guarentee it, and you should usually look for more concrete indications of an arborist's competence in addition.