Avoiding Tree Damage During Construction: NSW Pre-Build Guide

Damage prevention starts before site establishment

Most tree damage on NSW construction sites is preventable, and the prevention happens long before the first excavator arrives. The patterns we see on damaged-tree sites trace back to:

• Inadequate AIA at design stage that didn't fully scope the encroachment
• No Tree Protection Plan in the construction documentation
• No Project Arborist engaged, or engaged too late
• No pre-construction inspection on file
• Site induction that didn't cover tree protection

Get those five things right at the start and most construction-stage damage is structurally avoided. This post walks through each.

Step 1: Design with the trees, not against them

The cheapest tree protection is a design that doesn't encroach. The AIA at DA stage classifies each retained tree's encroachment under AS 4970-2025 as Minor (less than 10% of NRZ), Moderate (10-20%) or Major (over 20% or any SRZ). Each tier triggers progressively more rigorous (and expensive) mitigation.

Shifting a slab edge or driveway by half a metre during design can often drop a tree from Major to Minor, saving thousands in air spade investigation and mitigation costs, and weeks in the DA timeline. The conversation between architect and consulting arborist is most productive at concept and early design, before footprints are locked.

Step 2: Get the Tree Protection Plan into the build documentation

The TPP is the drawn document showing TPZ fencing layout, ground protection, no-go zones, supervision schedule and reporting requirements. It comes out of the AIA. For it to work, it has to be:

• In the construction documentation set (alongside the architectural and engineering drawings)
• Printed and displayed at the site office and at each TPZ on site
• Referenced in the SWMS (Safe Work Method Statement)
• Covered in the site induction for every subcontractor

A TPP that sits in a PDF folder somewhere doesn't protect anything. The most common breach we see is "TPP exists, but no one on site has read it".

Step 3: Engage the Project Arborist early

Most NSW DAs with retained trees name a Project Arborist (sometimes called Supervising Arborist) as a condition of consent. The engagement should happen at the same time as engaging the structural engineer – before site establishment, not weeks into the project.

Specific Project Arborist responsibilities through construction:

• Pre-construction inspection – after fencing is installed, before any other works. Written report goes to council. This is the documentary evidence that the site started compliant.
• Supervision inspections – typically monthly through construction. Each inspection generates a brief written report. Issues identified and rectified.
• Damage incident response – 24-hour notification of any damage to a retained tree, assessment within days, remediation plan if needed.
• Pre-OC inspection – final tree-protection inspection before Occupation Certificate, supporting bond release.

Assurance Trees offers Project Arborist supervision from $1,200 + GST for a small residential project, with programmed rates for builders running multiple projects.

Step 4: Compliant fencing before anything else

AS 4970-2025 specifies 1.8 m chain-wire fencing on steel star pickets at maximum 2 m centres. "Tree Protection Zone – No Entry" signage on the fence at no more than 5 m intervals, visible from inside the site. This fencing has to be in place BEFORE any other site works.

Plastic mesh, single-line bunting and yellow tape strung between corners are not compliant and council inspectors regularly fail sites for using them. Compliant fencing costs $40-$80 per linear metre installed – cheaper than the PIN for non-compliance.

Step 5: Induction the whole site on tree protection

Every subcontractor mobilising onto the site needs to know:

• Where the TPZs are and that no entry is allowed
• What ground protection (if any) covers approved encroachment areas
• Where materials, machinery, parking and washout are designated outside TPZs
• The damage reporting protocol (immediate notification to Project Arborist)
• Spill protocol and where the spill kit is

A 15-minute toolbox talk at induction, documented attendance, raised again any time a new subcontractor mobilises. Cheap, effective.

Frequently asked questions