The process
How a development works
The Australian Standard for the protection of trees on development sites, AS 4970:2025, sets out when an arborist is needed and what for. Each stage builds on the one before, and the earlier the arborist is involved, the fewer trees end up as problems.
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Before design
Preliminary Arboricultural Report
Identifies the trees worth keeping and the room each one needs. Needed before design, so the layout is drawn around them.
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Final design
Arboricultural Impact Assessment
Assesses what the proposed works do to each tree. Councils require it with the application wherever works come near protected trees.
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Approval
Tree Protection Plan
Sets out how the retained trees are protected on site. Usually a condition of approval, needed before works start.
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Construction
Project Arborist
Supervises works near retained trees and attends hold points. Required wherever the approval conditions call for supervision.
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Completion
Sign-off
Certifies the tree protection was followed. Council needs it to close out the approval conditions.
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Services
Tree reports for development and construction
Preliminary Arboricultural Report
Which trees on your site matter, how much room they need and which can go — in your designer’s hands before the layout is drawn.
Read more →Arboricultural Impact Assessment
The report councils require when construction encroaches on the root zone of protected trees — what your build does to each tree, and what has to change.
Read more →Tree Protection Plan
The drawing and specification that keeps retained trees alive through construction — and keeps you compliant with the conditions on your approval.
Read more →Tree Management Plan
A whole-of-site plan: what trees you have, what condition they are in, what they will cost, and what needs doing in what order over the next five years.
Read more →Project Arborist
The named arborist on your approval — supervising works near retained trees, attending hold points, and signing off what council requires signed off.
Read more →Root Investigation
Finds the roots, identifies the tree, and establishes whether it is causing the damage: air spade, GPR, excavation and laboratory root ID.
Read more →Get a FREE Quote
Not sure where to start?
Send the address and where the project is up to. You'll get a straight answer on which reports you need, and a fixed quote.
Why bring the arborist in early
The cheapest time to find a tree constraint is before the plans are fixed. At that point a protected tree is a line on the drawing that the designer works around. After the plans are locked, the same tree means a redesign, an information request from council, or a harder approval pathway.
AS 4970:2025 asks for each tree's root zone to be given to every designer and engineer on the project, so the building, services and earthworks are all planned around the same lines. It also points to construction methods that reduce disturbance in the root zone, such as pier and beam footings, suspended slabs, cantilevered sections and screw piles. They are cheap to adopt at design stage and expensive to retrofit.
Development arborist questions
What order do the arborist reports come in?
- Preliminary arboricultural report, before design: identifies the trees worth keeping and their root zones, so the layout can be drawn around them.
- Arboricultural impact assessment, once the design is final: assesses what the works do to each tree, which council needs to decide the application.
- Tree protection plan, at approval: sets out the fencing and site rules for the retained trees, so the builder knows what to protect before works start.
- Project arborist, during construction: supervises works near retained trees and attends hold points, so the conditions are met.
- Sign-off, at completion: the project arborist certifies the protection was followed, which council needs to close out the approval.
Do I need an arborist for a development?
You do if there are protected trees on the site, or trees next door whose root zones reach your works, and in practice council will tell you so in the conditions on your approval. Most councils condition an arboricultural impact assessment where works come near protected trees, and many also require a tree protection plan and project arborist supervision. If there are no trees near the works, or none of them are protected, you may not need one at all. Send the address and we can check before you commission anything.
When should I bring an arborist in?
Before the design is locked, ideally once the site survey is done. Trees identified at that point become part of the layout. Trees identified after the plans are fixed become a redesign, a delay or a harder application.
Can one arborist do every stage?
Yes, and the standard expects it. AS 4970:2025 names the project arborist as the person who prepares the preliminary report, the impact assessment and the tree protection documents, then monitors and certifies the protection through to sign-off. Keeping one arborist means the site is not assessed twice and nothing is lost between stages.
How much does an arborist cost for a development?
It depends on the number of trees and how many stages you need. A preliminary report starts from $660 inc. GST, an impact assessment from $1,100 inc. GST and a tree protection plan from $770 inc. GST; the last two are usually quoted together at a reduced combined rate. Supervision is quoted on the programme. See pricing, or send the decision notice for a fixed quote.
Not sure what you need?
Describe the situation and you will get a straight answer about which report your council actually requires — including when the answer is that you do not need one.