When Should You Hire an Arborist?

Trees add serious value to a Kiwi property: shade in summer, privacy from the neighbours, habitat for native birds. But they also need looking after, and that’s where an arborist comes in. If you’ve been wondering whether it’s time to call one, here’s how to tell.

The tree is looking unwell

Trees can’t tell you they’re sick, but they do show it. Look for yellowing or wilting leaves outside of autumn, bare branches when the rest of the tree is in leaf, fungi growing on the trunk, or visible dead wood in the canopy.

Early action saves trees. A qualified arborist can often diagnose and treat issues before they spread, whereas a homeowner trying to DIY usually ends up making things worse. Catching root rot, borer damage or a fungal infection early can add years to a tree’s life.

Warning signs worth acting on quickly

• Mushrooms or conks growing at the base of the trunk
• Large cracks in the trunk or major branches
• Hollow sections when you tap the trunk
• Sudden leaning, especially after a storm
• Dead branches making up more than 10 per cent of the canopy

Branches are too close to your house or power lines

Overhanging branches are one of the most common reasons Kiwis call an arborist. They drop leaves into gutters, scrape against the roof in high wind, and create easy access for possums and rats.

Branches near power lines are more urgent. By law, if a tree poses a risk to overhead lines, you’re responsible for keeping it clear. Lines companies can issue a notice requiring you to act, and if you ignore it they may do the work and send you the bill. Never attempt this yourself: it’s dangerous and usually illegal without proper qualifications.

After a big storm

NZ storms can do a number on trees. Even if nothing came down, there’s often hidden damage: partly snapped branches hanging in the canopy, cracked main leaders, or weakened root systems from waterlogged soil. These are called widow-makers for a reason.

A post-storm inspection is worth booking if:

• You’ve had winds over 90km/h in the last few days
• A tree is noticeably more leaned than before
• You can see broken branches still hanging in the canopy
• Large trees are near the house, driveway or car parks

Before major work on your property

Planning a renovation, extension or new driveway? An arborist assessment should be part of the plan. Trees have protected drip lines, and damaging roots during construction can kill a tree slowly over the next few years.

Some councils also require an arborist report before you can remove or significantly prune protected trees. Auckland, Wellington and Christchurch all have scheduled trees and notable tree registers. Check with your local council before touching anything substantial.

When the tree is just too big

A tree that was perfect when you moved in can become a liability twenty years later. Large trees near the house, next to fences, or shading out the whole section often need reduction pruning to bring them back to a manageable size.

The key word here is qualified. Arborists trained under NZQA or ISA standards know how to reduce a tree’s canopy without shocking it or leaving ugly stubs. Bad pruning (often called topping) creates weak regrowth, invites disease and shortens the tree’s life. Don’t hand this job to whoever shows up with a chainsaw.

Routine health checks for mature trees

Big, established trees benefit from an arborist visit every three to five years, even when nothing seems wrong. These check-ups catch structural issues, deadwood, and early disease. Think of it like a WOF for your trees.

What a health check typically includes

• Visual inspection of trunk, branches and roots
• Assessment of crown density and deadwood
• Check for pests, disease or fungal activity
• Recommendations for pruning, feeding or mulching
• Risk rating for trees near buildings, roads or play areas

When removal is the right call

Sometimes a tree can’t be saved. Advanced decay, irreversible lean, or root damage from construction might mean removal is the only safe option. A good arborist will explain why, give you the evidence, and talk through options before going straight to the saw.

If removal is needed, check local rules first. Some trees are protected under district plans, and removal without consent can attract big fines. Your arborist should handle the consent paperwork if required.

Choosing the right arborist

Always confirm your arborist is qualified and insured. Look for NZQA certification, membership of the NZ Arboricultural Association (NZ Arb), and proof of public liability insurance. Ask for recent local references and written quotes that clearly explain what work will be done.

Find a qualified arborist near you

Browse our verified arborists by region: Auckland, Wellington, Christchurch, Hamilton, Tauranga or Dunedin. Each listing includes reviews, qualifications and service area details.