A Project Arborist (sometimes called Supervising Arborist) is an AQF Level 5 consulting arborist named in the DA conditions or construction certificate, responsible for supervising tree protection during construction. Most NSW DAs with retained trees name the Project Arborist as a mandatory deliverable. You do need one — council can issue a stop-work order if there’s no nominated arborist when an inspection happens. Engagement starts from $1,200 + GST for a small project.

Yes. The AIA is the design-stage document — it specifies what protection is required. The Project Arborist’s inspection reports are the construction-stage evidence that the protection is in place and working. Most NSW DAs explicitly require both. The pre-construction inspection happens once; supervision inspections happen monthly or per-stage; the final inspection releases the tree-protection bond.

Notify the Project Arborist immediately. Document the damage with photographs. The Project Arborist will assess the impact and recommend remedial works (e.g. crown reduction, air spade investigation, monitoring, replacement). Don’t try to hide the damage — council inspectors usually find it, and the penalty for unauthorised damage is higher than the penalty for declaring it. If the tree subsequently dies, council may order replacement plantings at substantial cost.

No. AS 4970-2025 specifies 1.8 m chain-wire fencing on steel star pickets at maximum 2 m centres. Plastic mesh, bunting, or single-line tape is not compliant. Council inspectors regularly fail sites for inadequate fencing. The compliant fencing is $40-$80 per linear metre installed and lasts the project — cheaper than a stop-work order.

This is “encroachment” under AS 4970-2025 and is allowed where unavoidable, BUT must be done with: (a) ground protection (porous geotextile + 100 mm hardwood mulch or engineered panels), (b) no machine excavation, (c) hand or air spade work only, (d) supervision by the Project Arborist, (e) any cut roots over 50 mm diameter cleanly hand-cut with arborist sign-off. The detailed protocol comes from the AIA / TPP for your site.

Tree-protection bonds are sized by council, usually from the indicative value of the retained trees. Common range $2,000-$50,000+ per tree depending on size and council. Released after the final tree-protection inspection by the Project Arborist confirms the trees are alive and undamaged. Hold the bond until the trees are confirmed established (12 months after construction completion is typical for high-value trees).

Penalty Infringement Notices (PINs) start at $1,500 for an individual / $3,000 for a corporation. Court-imposed penalties under the EP&A Act 1979 reach $110,000 for individuals / $1,100,000 for corporations / $1,650,000 for repeat corporate offences. Council can also issue stop-work orders (lost productivity), order remedial works (replanting at scale), and refer matters to NSW LEC.

If there are retained trees on or near the site and council protects them under their DCP / TPO, the rules apply regardless of whether the DA had an AIA. The size threshold for a council-required AIA varies by council, but the protection rules apply to any tree above the protection threshold. If you’re unsure whether trees on your site are protected, run our Tree Removal Permission Wizard first.

Street trees are council assets. You cannot damage them, prune them, or excavate within their TPZ without council consent. If your works are near a street tree (kerb, driveway crossover, services connection), notify council before works and get their tree officer to nominate any specific protection measures. Damage to a street tree is a serious offence and council can order replacement of a mature street tree at $5,000-$15,000+.