In Canberra, any tree that is 8 metres or taller, has a canopy 8 metres or wider, or a trunk circumference of 1 metre or more at 1.4 metres above the ground is a protected tree under the Urban Forest Act 2023, and you cannot remove it, do major pruning, or build groundwork inside its Tree Protection Zone without written approval from the ACT Government. Penalties for getting this wrong run up to $80,000 for an individual and $405,000 for a corporation, and the application process can take several weeks, so this is not something you sort out at the last minute.

I've been in the Canberra building industry for 19 years, the last 5 of those running Rentoule Projects, and the tree protection question comes up on roughly half the projects I quote. Most homeowners are surprised by how broad the rules are, and quite a few are caught out by the fact that the goalposts moved in 2024. This guide walks through what the current rules actually mean for your project: what counts as a protected tree, where you can and cannot build, how to apply to remove one, what it costs, and the practical builder's view on managing trees on a renovation or new build site.

What is a protected tree in Canberra

The ACT Government changed the tree protection rules on 1 January 2024 when the Urban Forest Act 2023 replaced the old Tree Protection Act 2005. The thresholds tightened. Under the old law a tree had to be 12 metres tall or 12 metres of canopy to be regulated. Under the new law, the thresholds are:

  • 8 metres or taller in height, or
  • 8 metres or wider in canopy spread, or
  • 1 metre or more in trunk circumference, measured at 1.4 metres above natural ground level, or
  • A dead native tree at least 1.4 metres tall with a trunk circumference of 1.88 metres or more (because dead trees are habitat for native fauna)

If your tree meets any one of those four tests, it is a regulated tree. Most of the established eucalypts, cedars, oaks and elms on Canberra blocks built before 1990 hit at least one of those thresholds. In suburbs like Ainslie, O'Connor, Yarralumla, Curtin, Deakin, Forrest, Red Hill and most of the Inner North and Inner South, you should assume the mature trees on the block are regulated until an arborist confirms otherwise.

There is also a separate category called registered trees, which are trees of exceptional cultural, heritage or environmental value. These are held on the ACT Tree Register and have even stricter rules than regulated trees, including approval required for minor pruning.

What is the Tree Protection Zone (TPZ)

The TPZ is the no-go zone around a protected tree. Under the Urban Forest Act 2023, the TPZ is defined as the largest of:

  • The full area under the canopy of the tree (the drip line)
  • A 2-metre buffer around the vertical projection of the canopy
  • A 4-metre buffer around the trunk, measured at 1 metre above ground level
  • Any area specified in an approved tree management plan for your project

Picture a mature gum tree with a 10-metre canopy. Its TPZ extends from the trunk out to about 7 metres on each side (5m canopy radius plus 2m buffer). For a single dwelling on a 700m2 inner-suburb block, that one tree can render a substantial slab of the block effectively un-buildable without specific approval and a tree management plan from a qualified arborist.

You can build outside the TPZ without specific tree approval. You cannot do any of the following inside the TPZ without approval:

  • Excavate
  • Compact the soil with vehicles or stored materials
  • Stockpile material
  • Change the natural ground level by cut or fill
  • Lay impervious surfaces (concrete, asphalt, paving)
  • Install footings, slabs or service trenches

That last point is the killer for most projects. A new dwelling, extension, or driveway that wants to sit inside the TPZ of a protected tree needs a tree management plan and an approved tree activity application, and even then the approval comes with conditions: root protection fencing during construction, supervised excavation, pile foundations rather than slab, no soil-level changes within the canopy.

What you can do without approval

The Urban Forest Act 2023 permits some minor work on regulated trees without an approval. Minor pruning is allowed if all of the following are true:

  • You're removing deadwood only, or
  • It's the first pruning of the calendar year and affects less than 10% of the canopy without altering the tree's overall shape
  • No limb you remove is 100mm or more in diameter (measured at the cut)
  • The pruning does not adversely affect the appearance of the tree
  • For fruit trees, pruning for fruit production is allowed if it follows the Australian Standard AS 4373

If you're not sure whether the pruning you want to do crosses any of those tests, get an arborist to confirm in writing before the chainsaw comes out. Once a limb is on the ground, the penalty risk shifts to you, and the ACT Tree Protection Unit do investigate.

How to remove a protected tree

If you want to remove a regulated tree, or do works inside its TPZ that would damage it, you need an approval. The pathway depends on whether you're doing the work as a standalone activity or as part of a building project.

Standalone tree removal (no building work)

You submit a Tree Activity Application online through Access Canberra. The application requires:

  • Tree location, species and dimensions
  • Your reason for the application (one of the legislated approval criteria: declining health, unacceptable risk, substantial damage to a building, inappropriate species for location, solar access blockage with medical certification, etc.)
  • An arborist report supporting your case (a Level 5 AQF qualified arborist is the standard expectation)
  • Photographs
  • If approved, you'll also need to sign a canopy contribution agreement before work commences

Approval timelines run anywhere from 6 weeks to 3 months depending on complexity, complaint volume, and whether the Conservator of Flora and Fauna requests additional information. Plan for at least 6 to 8 weeks.

Tree removal as part of a building project

If the tree removal is tied to a development application, building application, driveway application, or knockdown rebuild, you have two options:

  1. Lodge the tree activity application first, get it approved, then submit your DA or building application with the tree approval attached
  2. Lodge during the building approval process, supported by a tree management plan prepared by a qualified arborist

For projects we work on at Rentoule Projects, we generally prefer option 1 for clarity and to avoid the building approval stalling on a tree decision. Tree management plans are now compulsory for any ACT Government approval where the activity may impact a protected tree, so you can't avoid the arborist step regardless.

The canopy contribution: 2 new trees or $600 each

This is the bit most homeowners do not know about until they're well into the process. Under the Urban Forest Act 2023, when a homeowner is approved to remove a protected tree, you must enter into a canopy contribution agreement with the ACT Government. The agreement requires:

  • 2 replacement trees to be planted on the same block for every protected tree removed, OR
  • $600 financial contribution for each replacement tree that cannot be planted

So if your project requires removing two protected trees to make way for a new dwelling and you cannot accommodate the four replacement trees on the block, you're up for $2,400 in canopy contribution charges on top of the arborist costs, application fees, and the tree removal itself. For developers and non-homeowners, the contribution rates are higher again and calculated on a formula (currently $1.27 per year per square metre of canopy area over a 20-year restoration period).

Exemptions can be granted for financial or social hardship, and there is now an exemption for blocks where canopy cover remains at 30 per cent or more after removal, but these are not common.

What does it cost

Real-world costs for a typical Canberra renovation or knockdown rebuild involving protected trees:

  • Arborist site assessment and report: $800 to $1,800 depending on number of trees and complexity
  • Tree management plan (if building near retained trees): $1,500 to $3,500
  • Tree activity application fee: $0 to several hundred dollars depending on the category
  • Tree removal itself: $1,500 to $6,000 per mature tree, including stump grinding
  • Canopy contribution: 2 replacement trees on site (about $200 to $400 each planted) or $600 per tree not planted (up to $1,200 per removed tree for homeowners)
  • Root protection fencing and arborist supervision during construction: $2,000 to $5,000 for a typical project retaining one or two trees

For a knockdown rebuild on a tree-heavy Inner North block, the total tree-related budget can run $8,000 to $20,000 before the new house gets a single brick. That is real money and it should be costed into your feasibility from day one, not discovered after contract signing.

Penalties

The Urban Forest Act 2023 carries strong penalties. Damaging a protected tree or doing prohibited groundwork inside a TPZ without approval can result in:

  • On-the-spot fines issued by the Tree Protection Unit
  • Court-imposed penalties up to $80,000 for an individual
  • Court-imposed penalties up to $405,000 for a corporation
  • A criminal record for more serious offences

These penalties apply to homeowners, builders, contractors, arborists, and tree services equally. If you remove a protected tree without approval, every party involved is at risk, not just the person who held the chainsaw.

Jeff's practical builder view

If you're planning a renovation, extension, knockdown rebuild, or any project that touches the perimeter of your block, here is how I'd approach the tree question:

First, identify what's on your block. Walk the property with a tape measure. Any tree that's clearly over 8 metres tall, has a canopy near 8 metres wide, or a trunk girth over 1 metre at chest height is almost certainly regulated. When in doubt, assume it is and design around it from the start.

Engage a Level 5 arborist before you finalise the design, not after. The cost of a $1,500 arborist consultation at the design stage will save tens of thousands compared to redesigning a slab or footing layout after the building approval is conditional on tree retention.

Build the tree application timeline into your project program. Six to twelve weeks is realistic. If you sign a contract assuming you can start excavation in 4 weeks and the tree approval is still pending, you'll be paying me to sit on my hands or you'll be moving the start date.

Pre-application meetings are free and underrated. The Tree Protection Unit will meet with you (or your arborist or builder) via Access Canberra on 13 22 81 or tree.protection@act.gov.au before you submit. We've sat in pre-application meetings that saved a project from a refusal that would have cost the client six months. Use them.

Don't try to be clever. The Tree Protection Unit do investigate, neighbours do complain, and Google Street View has a date stamp. If a healthy mature tree disappears between one inspection and the next, someone will notice and you will be the one explaining it.

For projects where trees are central to the planning challenge, I always quote with the tree management costs separated as a line item, and the timeline allowing for the approval window. For more on how planning approvals fit into the broader renovation process, see our guide on DA approval in the ACT and our step-by-step renovation planning guide. If you're considering a knockdown rebuild or a dual occupancy on a tree-heavy block, get the arborist involved before the architect.

Where to find current information

The authoritative sources for ACT tree protection are:

Frequently asked questions

Can I remove a protected tree if it is damaging my house?

Yes, subject to approval. "Substantial damage to a substantial building, structure or service" is one of the legislated criteria the Conservator can consider when granting an approval to damage a regulated tree. You'll still need an arborist report supporting the claim and you'll still trigger the canopy contribution requirement.

Can I build inside a Tree Protection Zone?

Sometimes, with approval and a tree management plan. The Conservator can approve building inside a TPZ where the tree management plan demonstrates the works will not damage the tree, including root protection measures, supervised excavation, suitable foundation types (often piles instead of slab), and no changes to natural ground level inside the canopy. It is more involved than simply siting the build outside the TPZ.

What happens if I remove a protected tree without approval?

You and any contractor involved can be issued on-the-spot fines, prosecuted in court (penalties up to $80,000 for an individual and $405,000 for a corporation), required to plant replacement trees, and in serious cases receive a criminal conviction. The Tree Protection Unit do investigate and they accept anonymous reports from neighbours.

Does the Urban Forest Act apply to all trees, or just native ones?

Regulated trees can be any species. Native or exotic, eucalypt or oak, the size thresholds apply equally. The only species-specific rules apply to dead native trees, which are protected as habitat at a separate trunk circumference threshold (1.88 metres).

Do I need approval to prune a regulated tree?

Only if the pruning crosses into "major pruning" territory: removing limbs 100mm or more in diameter, or affecting more than 10% of the canopy, or altering the tree's overall shape. Minor pruning of deadwood or first-of-year light pruning is permitted without approval. If you're not sure, get an arborist to put the answer in writing before any cuts are made.

Want a builder who knows the tree question inside out?

If you're planning a project on a tree-heavy Canberra block and want a builder who has been through this process more times than you can count, get in touch. Coffee's on me. I'd rather have a 30-minute conversation about your trees before you've signed anything than untangle an enforcement order in 6 months' time.