When a large tree is protected: Council, the arborist, and how far it sits from the house

A large tree on a Sydney block is rarely just a tree. In the Inner West, around Vaucluse, and on the Upper North Shore at West Pymble, Gordon and St Ives, most substantial trees are prescribed. Pruning or removal usually needs a Council permit, a Development Application, or both.

DC runs into this on courtyard jobs because a fence footing, a paved room or a service trench can sit inside a tree’s root zone even when nobody planned to take the tree out. This post sets out the approval path, what a consulting arborist looks for, and how bushfire distance rules sit beside tree protection.

It is a practical guide, not legal advice. Check the current DCP, a Section 10.7 certificate and the NSW RFS maps for the exact lot before anyone puts a saw in.

Why the tree is usually protected

Tree protection in NSW is a stack of rules, not a single ban.

The Biodiversity and Conservation SEPP lets each council declare which trees need a permit. The council DCP then sets the size trigger, the exemptions, and whether a permit is enough or a full DA is required. The LEP can add heritage items, conservation areas and significant-tree lists. Work on site is expected to follow AS 4970 (trees on development sites) and AS 4373 (pruning). On bushfire-prone land, Planning for Bush Fire Protection 2019 and the 10/50 Vegetation Clearing Code sit on top of that stack.

Typical size triggers — always confirm for the address:

• Inner West — often 4 m high, or a smaller tree with a large trunk at ground

• Woollahra (Vaucluse and nearby) — taller than 5 m, or a crown wider than 3 m

• Ku-ring-gai (West Pymble, Gordon, St Ives) — 5 m high, or a trunk 150 mm or more at ground

Heritage trees, conservation areas and street trees are stricter. A protected tree cannot be removed as part of a Complying Development Certificate. Either it stays and is protected during the build, or it is assessed in a DA.

Permit or DA?

Tree works permit covers many private prunes and removals that are not tied to a building DA and are not heritage-driven. All owners sign. Council may still want an AQF5 arborist report.

A development application is required when the tree is coming out as part of other work (courtyard, pool, driveway, new dwelling), when it is listed or in a heritage conservation area, or when the work will hit the protection zone of a tree that must stay.

Council does not cut private trees. The report is written by a consulting arborist (AQF5). The cut is done by a practising arborist (typically AQF3). Many councils will not accept a report from the same company that wants the removal contract.

Imminent danger is a narrow exception. Leaves in the gutter are not imminent. Councils want a TRAQ or QTRA assessment from an AQF5 arborist, plus photos, before they issue expedited consent. Unapproved removal is treated as vandalism.

What the arborist is looking for

A proper inspection of a substantial tree is not a glance from the driveway.

They record species, height, crown spread, trunk diameter at 1.4 m and at ground, and whether it is one stem or a group. They read health — leaf density, dieback, decay, pests, old topping. They read structure — lean, root-plate lift, weak unions, cavities, soil heave at the base. A large tree often needs more than a ground view.

They also score landscape and habitat value: streetscape, screening, hollows, indigenous species, heritage. Then they score risk — chance of failure, what it would hit, and how bad that would be. A tree over a play area is not the same tree as one over the back corner of the lot.

Below ground is where landscape work lives. Using AS 4970 the arborist draws two circles:

• Tree Protection Zone — room the tree needs to stay alive (as a guide, about twelve times the trunk diameter)

• Structural Root Zone — the smaller circle of roots that hold it up

They overlay the proposed courtyard, fence footing or trench and calculate how much of the protection zone is eaten. Hit the structural roots, or take more than a small slice of the protection zone, and the choices are redesign, sensitive construction, or removal.

Neighbour and street trees go in the same report. An 1800 mm masonry footing through the neighbour’s structural roots is both a planning problem and a civil one.

What will not, on its own, get a large healthy tree approved for removal: leaf litter, shade on a courtyard, fruit drop, or a cheaper quote without the tree. Health, structure, risk, or an unavoidable development impact that has already been designed down — those are the arguments that stand up.

Fire, and why metres from the house matter

A tree close to a dwelling is fuel. Distance is how the fire rules turn that into a number.

Most houses lost in NSW bushfires fail from embers, which can travel well over 100 metres. Direct flame and radiant heat matter at much shorter range. Radiant heat drops quickly as the gap between vegetation and the wall increases. That gap is the Asset Protection Zone.

On mapped bush fire prone land, new work is assessed against Planning for Bush Fire Protection 2019. The width of the zone depends on vegetation type, slope and the regional fire weather. Forest on a slope toward the house needs more distance than rainforest on the flat. Closer vegetation means a higher Bushfire Attack Level under AS 3959 — heavier construction — or a refusal if the zone will not fit on the lot.

Managed ground next to the house is not a bare yard. RFS standards typically want canopies kept off the roof line (conditions often speak of about five metres from foliage to the building), space between canopies, no bark mulch hard against the wall, and low ground fuel. Those figures appear in consents. They are not a licence to clear the block.

The 10/50 rule — what it does and does not do

This is the line people quote as “I can take any tree within ten metres.” It is narrower than that.

If the lot is in a 10/50 Vegetation Clearing Entitlement Area on the RFS tool on the day of the work:

• trees on your land may come down without Council approval where the trunk (more than 30 cm circumference at 1.3 m) is within 10 metres of the external wall of a habitable dwelling

• shrubs, not trees, may be cleared within 50 metres

• branches within 10 metres may be pruned even if the trunk is further away

You cannot use the neighbour’s house to justify a cut on your land without their written consent. Steep slopes, certain waterways and other mapped exclusions apply. 10/50 is for existing dwellings. It is not a tool to clear a site for a new DA. Entitlement areas change — check the map that day.

When fire rules and tree rules collide

On an Upper North Shore street both regimes can apply to the same tree.

If 10/50 applies and the trunk is within 10 metres of the house, removal may proceed without a Ku-ring-gai permit — if every code condition is met that day. Keep a record of the map check.

If the land is bushfire-prone and you are lodging a DA, Planning for Bush Fire Protection may require an asset protection zone even where the tree sits outside the 10-metre line. The arborist report and the bushfire report have to tell the same story.

In much of the Inner West and many Woollahra courtyards, 10/50 does not apply. “It is close to the house” is not an exemption. You need the permit or DA path.

Heritage listings and mapped exclusions can still stop a 10/50 cut. Get advice before the saw starts.

And if Council required the tree to stay, a lighting trench or a fence footing through the structural root zone can kill it just as effectively as a permit you never got.

How DC handles it on a courtyard job

We confirm the council, heritage, bushfire map and 10/50 status for the address. We measure the tree against the walls and the proposed work. An independent AQF5 arborist is engaged before the courtyard is drawn as if the tree were already gone.

If the tree can stay, footings and services are designed outside the structural root zone. If removal is the honest outcome, the right application goes in with the report — and a bushfire assessment where the land is mapped. After consent, a qualified practising arborist does the work, and we plant what the consent requires.

Need the tree assessed before the garden is designed?

DC works across the Inner West, the eastern harbour suburbs around Vaucluse, and the Upper North Shore at West Pymble, Gordon and St Ives. Get in touch before the footing is set out