Storm Season Tree Safety Checks for Your Property

New Zealand's storm season — broadly autumn through winter — brings powerful winds, heavy rain, and saturated soils that can turn a seemingly healthy tree into a serious hazard overnight. Taking time to inspect your trees before the worst weather arrives is one of the smartest things you can do to protect your home, your family, and your neighbours. Prevention is always cheaper than the aftermath of a fallen tree through a roof.

Why Tree Safety Matters Before Storm Season

NZ's climate varies enormously — coastal properties face salt-laden gales, inland areas can experience sudden frost and snow loading, and much of the country receives intense rainfall that saturates root zones and destabilises trees. BRANZ research consistently highlights that wind-driven debris and falling trees are among the most common causes of storm damage to NZ homes.

A structurally compromised tree may look perfectly fine from the street. Hidden decay, root damage, co-dominant stems, and previous poor pruning can all create failure points that only become apparent when a tree is under load. Identifying these issues in late summer or early autumn — before the storms arrive — gives you time to act safely and affordably.

Season-by-Season Tree Maintenance Checklist

Late Summer / Early Autumn (February – April) — Inspect and Plan

• Walk your property and look at every significant tree from multiple angles, including from inside upper-storey windows.
• Check for dead or dying branches (no leaves, brittle bark, fungal brackets at the base or on the trunk).
• Look for cracks or splits in the trunk or at branch unions — these are serious warning signs.
• Note any co-dominant stems (two trunks of similar size growing from one point) — these are prone to splitting under wind or snow load.
• Inspect root zones: heaving soil, exposed roots, or a noticeable lean that has developed recently all warrant professional assessment.
• Check trees near power lines, the house, fences, and the boundary — these carry the highest consequence if they fail.
• Photograph any concerns and note the tree species if you can — this helps when briefing an arborist.
• Book a qualified arborist early. Demand surges after the first big storm, so getting in ahead of the rush saves time and money.

Autumn (April – June) — Act on Findings

• Have a certified arborist carry out any recommended pruning, crown reduction, or removal before the ground becomes too wet and access becomes difficult.
• Remove deadwood from the canopy — dead branches are the first to fail in high winds.
• Consider cable bracing for trees with co-dominant stems or significant lean — this is specialist work.
• Clear gutters and downpipes of leaf litter that builds up under deciduous trees.
• Mulch around root zones (keeping mulch away from the trunk) to help retain moisture and reduce soil compaction.

Winter (June – August) — Monitor and Respond

• After each significant storm, do a post-storm walk of your property in daylight once it is safe to do so.
• Look for newly cracked branches, hanging limbs (widow-makers), and any fresh lean in trees.
• Do not attempt to remove hanging branches yourself — this is extremely dangerous and should be left to a professional arborist with the right equipment.
• Check that storm drains and channels around tree root zones are clear to prevent waterlogging.
• If a tree falls and damages a structure, contact your insurer promptly and document everything with photos.

Spring (September – November) — Recover and Reassess

• Inspect trees again once foliage returns — new growth can reveal dead sections that weren't obvious in winter.
• Address any root disturbance caused by saturated soils and wind rock.
• Plan any new planting with storm resilience in mind — choose species and locations that won't create future hazards.

Common Warning Signs of a Hazardous Tree

Common Mistakes Homeowners Make

• DIY pruning large trees — cutting branches over roughly 3–4 metres up, or near power lines, is dangerous without proper training, equipment, and insurance. Falls from height are a leading cause of serious injury in NZ. WorkSafe NZ has clear guidance on working at height safely.
• Topping trees — cutting the main leader back to a stub looks tidy but creates weak, fast-growing regrowth and long-term structural problems. A qualified arborist will never recommend topping as a solution.
• Ignoring council rules — many trees are protected under district plan rules or resource consent conditions. Always check with your local council before removing or significantly pruning a tree. Fines for removing a protected tree can be substantial.
• Waiting until after a storm — emergency arborist callouts cost significantly more than planned work, and availability is limited when everyone needs help at once.
• Assuming a leaning tree is fine — a gradual lean is sometimes natural, but a lean that has developed or worsened recently, especially after rain, needs professional eyes on it urgently.

What You Can Safely Do Yourself

Homeowners can safely carry out light maintenance such as:

• Removing small, low branches (under about 2 metres) with clean, sharp secateurs or loppers
• Raking and clearing leaf litter and small debris from around tree bases
• Watering young trees during dry spells to keep root systems healthy
• Applying mulch around root zones

Anything involving ladders, chainsaws, branches near power lines, or trees of significant size should be left to a qualified professional.

When to Call a Professional

Contact a certified arborist — look for members of the New Zealand Arboricultural Association (NZAA) — whenever you observe any of the high-risk warning signs in the table above, or if you are simply unsure. A professional assessment is relatively inexpensive compared to the cost of emergency tree removal or, worse, storm damage to your home.

Never approach a tree that has fallen on or near power lines. Call your electricity lines company immediately and keep everyone well clear. This is not a situation for a tradesperson — it requires the lines company to make the scene safe first.

If a tree is overhanging a neighbour's property or you have a dispute about a boundary tree, Tenancy Services and your local council can provide guidance on your legal obligations.

You can find qualified, insured local arborists in your area at tradedirectory.co.nz. Getting two or three quotes for larger jobs is always a good idea.

Sources & Further Reading

• BRANZ — Building Research Association of NZ
• WorkSafe NZ — Working at Height
• MBIE Building Performance — NZ Building Code
• Consumer NZ — Hiring Tradespeople
• Licensed Building Practitioners — LBP Register