Checking an arborist before you say yes

How to read those levels

NZQA also lists introductory, intermediate and advanced arboriculture certificates at Levels 2, 3 and 4. On one crew you might meet someone newer assisting under limited supervision, working alongside a lead with a Level 4 or Level 5 qualification. Assessing whether a tree is likely to fail, or writing a report a council will rely on, is the kind of work the Level 6 diploma trains for.

So the useful question isn't just whether someone is qualified, but whether their qualification matches the job you're asking them to do. NZ Arb recommends that every arborist doing arboricultural work has current competency for that work, and WorkSafe's 2012 arboriculture code says people doing it should be suitably qualified, with their competency documented.

Where qualifications carry real weight

Some council rules lean on them directly. Christchurch City Council's benchmark for a works arborist is the Level 4 Horticulture Services (Arboriculture) standard plus on-the-job experience, and for a technician arborist the Level 6 diploma standard plus skill in tree inspection and evaluating hazardous trees. It publishes lists of companies with council-approved technician, supervising and works arborists for work on protected trees, and a dead or failed significant tree there needs a Tree Removal Certificate prepared by a technician arborist.

In Auckland, the Unitary Plan permits dead wood removal from a notable tree when a qualified arborist does it; done by anyone else, it needs resource consent. If your tree is listed, the arborist's training changes what the rules allow. Our Auckland tree rules and Christchurch tree rules pages have the detail.

NZ Arb membership and Registered Master Arborists

The New Zealand Arboricultural Association (NZ Arb, at nzarb.org.nz) is the industry body. Its membership is open to professional arborists and tree managers, and also to any person or group interested in amenity trees, so membership on its own tells you someone cares about trees, not what training they have.

Registered Master Arborist status is different. NZ Arb says assessment covers industry, arboricultural and legislative knowledge, practical ability, and proven client service and business systems, and its Find a Master Arborist directory lets you confirm a name.

Insurance: what to ask for

Ask whether the business carries public liability insurance that covers tree work, and ask for the insurer's name and what the policy covers, in writing. A branch through a roof or a neighbour's fence during the job is exactly what that cover exists for.

Check your own side too. The Insurance Council says trees themselves generally aren't covered by a house policy, and suggests reading your policy wording on damage from falling trees and branches and asking your insurer if you're unsure.

Ask how the crew will run the job safely as well. NZ Arb's Best Practice Guide says the Health and Safety at Work Act 2015 is the over-arching law for workplace health and safety, so a crew working to it should be able to tell you how they'll set up the site and keep people clear.