The cost of getting tree protection wrong
Damage to retained trees during NSW construction is one of the most common reasons projects get council orders, DA breach action and civil claims. The penalty range under the EP&A Act 1979 runs from $1,500 (Penalty Infringement Notice) to $1,650,000 (corporate repeat offence). Add to that stop-work productivity loss, replacement-planting orders, and damaged-client relationships.
The good news: most breaches are simple to avoid. They happen because someone on site assumed something was OK that isn’t, or because the Project Arborist wasn’t engaged early enough, or because materials drifted into the TPZ over a long project. Below are the 10 patterns we see most often, with the fix for each.
The 10 most common breaches
- No TPP on site or not referenced
- Non-compliant TPZ fencing
- Machine excavation inside TPZ
- Materials stored in the TPZ
- Vehicle traffic / parking in the TPZ
- Concrete washout or chemical spill in TPZ
- Soil-level changes around trees
- No Project Arborist engaged
- Skipping the pre-construction inspection
- Damage discovered late and hidden
The 10 breaches
1. No Tree Protection Plan (TPP) on site, or no one referencing it
The TPP is the drawn document that defines TPZ fencing layout, ground protection, no-go areas and supervision schedule. It comes out of the AIA. On many sites it’s filed somewhere in the project documents and nobody on site has actually looked at it. Result: improvised tree protection that doesn’t match what the DA approved.
2. TPZ fencing not AS 4970-2025 compliant
AS 4970-2025 specifies 1.8 m chain-wire fencing on steel star pickets at maximum 2 m centres. Plastic mesh, single-line bunting, or yellow tape strung between corners is not compliant and council inspectors regularly fail sites for it. Compliant fencing costs $40-$80 per linear metre installed.
3. Machine excavation inside the TPZ
Excavator buckets cutting through the TPZ for service trenches, paving, footings, or any other subgrade work. This is the most damaging breach because cut roots over 50 mm can compromise the tree’s stability and dramatically reduce future life expectancy. AS 4970-2025 specifies hand or air spade excavation only within any TPZ.
4. Materials stored in the TPZ
Bricks, timber, scaffold components, tools, the site bin, the site toilet, the formwork stockpile — anything heavy or chemical drifts into the TPZ over a long project because there’s space inside the fence. Soil compaction from materials weight, plus heat reflection from materials, plus chemical leaching, all damage the tree slowly.
5. Vehicle traffic or parking inside the TPZ
Site vehicles parking in the TPZ “just for a few minutes”. The trailer dropped off and left for the day. The concrete truck reversing into position. Each pass compacts the soil. Soil compaction is invisible damage that often kills trees 3-5 years after construction ends, well after the project has closed out and the builder has moved on.
6. Concrete washout or chemical spill in the TPZ
The concrete truck washes out its chute “over there” because it’s convenient. The fuel can spills near the trees. Paint solvent goes into the drain that runs past the TPZ. Concrete washout has a high pH that kills soil microorganisms; fuel and solvents are directly toxic to roots.
7. Soil-level changes around trees
“We had to raise the ground level around this tree for the new driveway.” Adding fill against a tree’s root flare smothers the surface roots and dramatically reduces oxygen availability. Removing soil exposes feeder roots to desiccation. Both damage the tree but in different ways. AS 4970-2025 specifies no soil-level changes greater than 100 mm within any TPZ without specific arborist sign-off.
8. No Project Arborist engaged (when DA conditions require one)
The DA conditions name a “Project Arborist” or “Supervising Arborist” but no one was actually engaged. Council can issue a stop-work order if an inspection happens and there’s no nominated arborist. Common on smaller residential projects where the builder assumes the AIA arborist’s role ends at DA approval.
9. Skipping the pre-construction tree-protection inspection
The Project Arborist’s pre-construction inspection is usually a DA condition: after fencing is installed but before any other works, the Project Arborist confirms TPZ fencing, ground protection, signage and personnel induction are in place. Skipping this inspection means there’s no documentary evidence that the site started compliant. If anything goes wrong later, the lack of pre-construction evidence works against the builder.
10. Damage discovered late and hidden
A subcontractor cut a root with a trencher and backfilled the trench. A truck reversed over an area inside the TPZ and the soil is now compacted. Damage to bark from machinery brushing past. These get hidden in the hope nobody notices, and they sometimes succeed in the short term — but the tree’s response 2-5 years on (decline, death) gives the game away. Council orders replacement plantings at that point, and the builder’s insurer often pursues recovery.
Audit your site against AS 4970-2025 in 60 seconds
Free 12-question Builder Compliance Checklist. Scored compliance %, gap list, legal-exposure tier and cost-of-fix vs cost-of-breach comparison. Use before a council inspection or as a standing site discipline.
What it costs when you get caught
The financial exposure scales with the offence severity and the offender type:
- Penalty Infringement Notice (PIN): $1,500 individual / $3,000 corporation per offence. Issued by council on-the-spot for visible breaches.
- Court-imposed penalties (EP&A Act 1979): Up to $110,000 for individuals, $1,100,000 for corporations, $1,650,000 for repeat corporate offences.
- Council remedial orders: Replacement plantings at mature-tree scale — $5,000-$50,000+ per tree replaced, plus 2-year establishment care.
- Stop-work orders: Typical productivity loss $5,000-$30,000 per day on a mid-size site. Some stop-work orders run weeks.
- Tree-protection bond loss: Council holds bonds of $2,000-$50,000+ per protected tree. Forfeited if remediation isn’t completed properly.
- Civil claims: Where the builder or contractor caused damage that affects a third party (neighbour tree, council street tree), separate civil claim from the third party.
Against this, Project Arborist engagement is typically $1,200-$5,000 + GST for a single-stage residential project, $5,000-$15,000 + GST for a larger build with monthly inspection cycles, and $15,000+ for complex commercial. The economics strongly favour engaging the Project Arborist rather than risking the breach.
The single thing that prevents most breaches. A nominated Project Arborist with a current engagement and monthly inspection cadence. Subcontractors behave differently when the project has an arborist visible on site each month. Council inspectors find sites with a Project Arborist far more cooperative to deal with. The cost of the engagement is a fraction of the cost of avoiding a single stop-work order.
Practical site-discipline checklist
Five questions to ask at your weekly site meeting:
- Are all TPZ fences still up, intact, and signed?
- Is any subcontractor proposing to work in or near a TPZ this week?
- Has anything new been stored, parked or driven inside a TPZ since last week?
- Are we on schedule for the next Project Arborist inspection?
- Has anyone reported any damage, even minor, to a retained tree?
Adding tree-protection as a recurring agenda item costs five minutes and prevents the slow-drift breaches that cause most council action.
FAQ
How does council actually find out about a breach?
Most commonly: scheduled DA-compliance inspections (council inspectors who know which sites have retained-tree conditions); complaints from neighbours; complaints from the Project Arborist if the builder ignores their inspection findings; observable damage post-construction discovered during the OC (occupation certificate) inspection. The bond release process is also a discovery point if trees are visibly damaged.
If a subcontractor caused the damage, am I still liable?
As the builder / principal contractor, yes – you’re responsible for compliance with DA conditions on the whole site. Internal contracts can pass liability to the subcontractor but council acts against you. The subcontractor’s PI insurance and contract terms determine cost recovery.
What about street trees adjacent to my site?
Street trees are council assets and the same protection rules apply. If your works are near a kerb tree, notify council before starting and get specific protection measures from the tree officer. Damage to a council street tree often attracts higher penalties than damage to a tree on private land.
Can I get the Project Arborist to come less often if my project is small?
Yes – inspection frequency is scoped to the project. Some smaller residential projects only need a pre-construction inspection, a mid-construction check, and a pre-OC inspection. The DA conditions usually specify minimum frequency. The Project Arborist can recommend the actual cadence for your project at engagement.
What’s the cost of Project Arborist supervision?
Assurance Trees’ Project Arborist engagements start at $1,200 + GST for a small residential project (pre-construction + 1-2 supervision visits + completion). Mid-size projects with monthly inspection cycles $3,000-$8,000 + GST. Major commercial and multi-stage projects scoped individually. Programmed rates available for builders with multiple concurrent projects.
Note. This is general educational content for NSW construction. Specific DA conditions for your project take precedence. For your specific site, engage a Project Arborist for a written engagement scope tied to AS 4970-2025 and your DA’s conditions of consent.
Need a Project Arborist for your NSW build?
Assurance Trees provides Project Arborist supervision for NSW construction sites. AQF Level 5, NSW Licensed Builder background, in-house air spade. Programmed rates for ongoing projects. Same-day call-out for stop-work mitigation.
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