Preliminary Arboricultural Report — GIS-Ready Tree Data Your Architect Can Design Around From Day One
A Preliminary Arboricultural Report (PAR) puts the tree constraints into your architect’s CAD or BIM software before the design is finalised — not after the AIA arrives with bad news. Survey-grade tree positions, NRZ and SRZ protection zones, retention values and preferred protection layouts, delivered as spatial data straight into AutoCAD, Revit, ArchiCAD or QGIS. AS 4970-2025 compliant. NSW-wide.
From $1,500 + GST · Combined PAR + AIA: typically near single-stage AIA costThe most expensive risk on a tree-affected project is the one your AIA was supposed to flag earlier
The pattern is familiar to every architect who’s done tree-constrained work: design develops to a respectable stage, the Arboricultural Impact Assessment is commissioned, and the report comes back saying the proposed setbacks impact trees that have to be retained. Now there’s a redesign — architect rework hours, cascading delays through the other consultants, finance timelines slip, the client loses confidence. On a serious project that’s not AIA-fee money. That’s tens of thousands of dollars and weeks of programme.
A Preliminary Arboricultural Report (PAR) flips the order. We survey the trees, calculate the NRZ and SRZ protection zones to AS 4970-2025, and deliver the tree positions + protection-zone polygons as GIS-ready spatial data that imports directly into your architect’s CAD or BIM environment. Tree constraints are visible in the design software from day one. When the formal AIA lands at DA stage, there are no surprises — because the design was built around the trees, not against them.
What is a Preliminary Arboricultural Report, and when do you need one?
A Preliminary Arboricultural Report (PAR) — sometimes called a Preliminary Tree Assessment — is the pre-design, pre-DA arboricultural deliverable that documents the trees on a development site, calculates their AS 4970-2025 protection zones, assesses retention value, and provides preferred Tree Protection Plan and Specification layouts that inform the design. The PAR runs before the architect’s design is locked in, so the tree constraints become design inputs rather than late-stage problems.
You typically need a PAR if your project is:
- A subdivision, multi-dwelling residential or commercial development on a vegetated site
- Architect-led design where retention of significant trees is a stated brief outcome
- A heritage-tree site where retention is non-negotiable and the design must accommodate
- A site with mature canopy, listed-significance trees or council-protected vegetation
- A civil or infrastructure project at feasibility / concept stage
- A government, schools or institutional project where tree retention sits in the project brief
- Any project where the question “are we designing this well around the trees?” actually matters
For simple single-dwelling sites with clear constraints, a single-stage Arboricultural Impact Assessment in one go is usually the right call. The PAR exists for projects where the design outcome itself is on the line.
The PAR → Design → AIA sequence — how it actually works
One coordinated arboricultural engagement across the project, sequenced so the design is informed by the trees from the start. Your architect designs in their own software, with the tree data live, knowing exactly what their proposed moves do to retention.
Preliminary Arboricultural Report (PAR)
Trees surveyed and mapped to centimetre-level accuracy. NRZ and SRZ protection zones calculated to AS 4970-2025. Retention values assessed (IACA STAR methodology) so the design team can prioritise retaining high-value trees and target lower-value trees for removal where impact is unavoidable. Tree positions + NRZ/SRZ polygons exported as GIS-ready data into your architect’s AutoCAD, Revit, ArchiCAD or QGIS environment. Preferred TPP/TPS layouts included to guide design.
Architect’s design
Design develops around the tree constraints and preferred protection layouts identified in the PAR. The architect can see every tree, every protection zone, every retention-value flag in their own design environment in real time. Design clashes are spotted immediately — while changes are still cheap to make.
Full Arboricultural Impact Assessment (AIA)
Uses the tree data already collected in the PAR + the now-finalised design. Quantifies the loss of any trees the design can’t retain and specifies the formal replacement / compensatory / offset planting regime council requires. Develops the formal Tree Protection Plan, Specification and council-ready documentation for the Development Application. No surprises. No redesigns. Because the AIA reuses PAR work, combined PAR + AIA cost is typically close to a single-stage AIA — you get the design advantage at no real premium.
What’s in our Preliminary Arboricultural Report
Every PAR is structured so the architect, civil designer and client get one document set that drives the design, the council submission and the construction phase — without re-doing the survey work each time.
Survey-Grade Tree Survey & Inventory
Every tree on and adjacent to the site identified, measured (DBH, height, canopy spread), photographed and species-confirmed. Positions captured to centimetre-level accuracy with our in-house Trimble R2 GNSS + RTX correction — not paced approximations.
NRZ, TPZ & SRZ Calculations
Notional Root Zone, Tree Protection Zone and Structural Root Zone calculated to AS 4970-2025 for every assessed tree. Polygons generated against survey-grade positions, ready to overlay onto the architect’s site plan in the next step.
GIS-Ready Spatial Data for Your Designer
Tree points and NRZ/SRZ polygons delivered as spatial data that imports directly into AutoCAD, Revit, ArchiCAD, QGIS or ESRI — not flattened PDFs you have to manually trace. Formats: AutoCAD DWG, GeoPackage, ESRI Shapefile, KMZ. Most consulting arborists can’t produce this. Your architect sees design clashes as they happen, in their own software.
Retention Value Assessment
Each tree assessed for health, structure, useful life expectancy and landscape / heritage significance using the IACA STAR methodology. Output is a retention-priority ranking that lets the design team prioritise retaining high-value trees and target lower-value trees for removal where impact is unavoidable.
Without proper arboricultural retention data, design teams default to retaining the trees that look biggest on the surveyor’s plan — widest canopy, thickest stem. That’s a trap. A large, declining gum with hollow stems and five years of useful life left isn’t worth bending the design for. A smaller, healthy specimen of a locally significant species with 80+ years of life ahead of it usually is. The PAR ensures your design prioritises retention by tree quality, not tree size — protecting the trees that genuinely warrant retention, and freeing the design from fighting for trees that don’t.
The PAR informs which trees the design should fight for. The formal loss assessment and replacement / offset planting specification happen later at AIA stage, once the design is locked in and the actual removals are known.
Preferred TPP & TPS Layouts
Indicative Tree Protection Plan fencing alignments and Tree Protection Specification requirements, sized to suit the constraints identified in the assessment. Not final — the formal TPP/TPS gets locked in at AIA stage once the design is concrete — but enough for the architect to design with proper protection layouts in mind from day one.
Constraint Plan & Design Notes
A plain-English summary of the arboricultural constraints affecting the site, written for the design team rather than the council assessor. Where setbacks need to fall, where excavation will trigger encroachment, where access routes can sit without compromising retained trees. The document an architect actually wants on their desk during concept design.
Who benefits most from the PAR → AIA approach
Architects & Town Planners
You design tree-constrained sites with the tree data live in your CAD/BIM software. No more discovering at AIA stage that the proposed footprint clips a retained tree’s NRZ. Your professional reputation, sat alongside an architect-grade arboricultural workflow.
“The consulting arborist that architects refer is itself a quality marker. Conrad Gargett and Shac engage us on tree-sensitive briefs — their reputation comes with the referral.”
Subdivision & Multi-Dwelling Developers
Layout, lot sizing and access road alignments designed around the tree constraints from concept stage. Trees that should be retained get retained — trees that don’t, don’t waste design hours pretending otherwise. Fewer council RFIs at DA stage because the design accounts for the trees.
Civil & Commercial Construction
For projects at concept or feasibility stage, the PAR gives the design team the arboricultural inputs they need to scope the works realistically. Useful when tendering or pricing a project where retained vegetation will materially affect construction sequencing.
Government & Institutional Projects
Where tree retention sits explicitly in the project brief — schools, hospitals, public infrastructure — the PAR gives the design consultants the constraint data to honour the brief without ambushing it at DA stage. Particularly valuable on heritage-listed sites and significant landscape settings.
Ready for the DA? The Arboricultural Impact Assessment follows naturally.
When your design is locked in, the AIA builds directly on the PAR — reusing the survey data, the protection-zone calculations and the retention assessment, and developing the formal Tree Protection Plan and Specification for council submission. Combined PAR + AIA cost is typically close to a single-stage AIA. See our AIA service →
Need standalone GIS tree mapping (no report)?
For engineering firms, surveyors and large developers who already have arboricultural input but need survey-grade spatial data, we deliver tree mapping as a standalone deliverable — Trimble R2 GNSS + RTX correction, full QGIS workflow, output in the formats your project team actually uses (GeoPackage, AutoCAD DWG, ESRI Shapefile, KMZ). See our Tree Surveys + GIS service →
Need to verify root locations before design is finalised?
For sites where retained-tree root distribution will materially shape the design (slab edges, footings, services trenches), we own our Air Spade and mobile compressor in-house — non-destructive root investigation done in days, not 2–3 weeks. Useful at PAR stage when the design team needs evidence about where the roots actually are. See our Root Investigation service →
Preliminary Arboricultural Report pricing & turnaround
Every PAR is delivered as a fixed-fee engagement. No hourly billing surprises. Price determined upfront based on tree numbers, site complexity and the spatial-data formats your design team needs.
The economic argument is simple. A single late-stage redesign caused by an AIA-stage tree-protection finding routinely costs $5,000–$50,000+ in architect rework hours and consultant ripple-on. A $1,500–$2,500 PAR before the design is finalised eliminates that risk entirely. For any project where the design isn’t trivial, this isn’t an expense — it’s risk insurance with a working deliverable attached.
Preliminary Arboricultural Report service areas across NSW
Maitland-based, with regular pre-design and PAR work across:
Request a Preliminary Arboricultural Report quote
Tell us about your project — we’ll come back within one business day with a fixed-fee PAR quote and confirm the spatial-data formats your design team needs.
Preliminary Arboricultural Report FAQs
What’s the difference between a PAR and an AIA?
A Preliminary Arboricultural Report (PAR) runs before the design is finalised, and is built to inform the design. It documents the trees, calculates the protection zones, assesses retention values and (critically) delivers the tree positions and NRZ/SRZ polygons as GIS-ready spatial data into your architect’s CAD or BIM software. It includes preferred TPP/TPS layouts to guide the design.
An Arboricultural Impact Assessment (AIA) runs after the design is locked in, and is built for council. It includes the formal Tree Protection Plan and Tree Protection Specification, written to AS 4970-2025 for the Development Application. Most AIAs include the TPP/TPS as part of the deliverable package.
There’s one more meaningful difference between the two stages: the AIA quantifies the loss of trees caused by the proposed impacts and specifies the replacement, compensatory or offset planting regime council requires. That work can only happen once the design is finalised — you can’t specify what to replant if you don’t yet know what’s being removed. At PAR stage we deliver the upstream input: tree-by-tree retention values, so the design team can prioritise retaining high-value trees and target lower-value trees for removal where impact is unavoidable. The PAR informs which trees the design should fight for; the AIA specifies what to do about the trees the final design doesn’t keep.
They’re not competing services — for tree-affected projects, they’re complementary stages. The PAR informs the design; the AIA documents the design’s impact for council. See our AIA page →
Why is the GIS-ready spatial data a big deal?
Most consulting arborists deliver PDFs — tree positions sketched onto a site plan that the architect then has to manually trace into AutoCAD, Revit or ArchiCAD. That’s hours of work for the architect, with positional drift baked in at every step. It also means tree constraints don’t show up in the design model: they sit in a PDF on the side, easy to overlook during design moves.
We deliver the tree positions and NRZ/SRZ protection-zone polygons as actual spatial data — AutoCAD DWG, GeoPackage, ESRI Shapefile, KMZ, formats to suit. Your architect drops the file into their design environment and the trees become first-class design entities, geo-referenced to centimetre-level accuracy. Design clashes show up the moment they happen, not at AIA stage three months later. This is genuinely unusual among NSW consulting arborists — most don’t have the survey-grade GNSS equipment (Trimble R2 + RTX) or the GIS workflow (QGIS) to produce it.
How much does a Preliminary Arboricultural Report cost?
PARs start from $1,500 + GST for smaller sites at concept stage. Larger sites, subdivisions and projects requiring multiple spatial-data format outputs are quoted individually. Every PAR is delivered as a fixed-fee engagement — you get the total price upfront, no hourly billing surprises.
Combined PAR + AIA cost is typically close to a single-stage AIA because the AIA reuses the survey, calculation and assessment work the PAR already completed. Practically, you get the design-stage advantage at no real premium — just split over two stages instead of one.
How long does a PAR take to prepare?
Standard turnaround is two weeks from site inspection to delivered report and spatial data. Fast-track delivery is available where a design or programme deadline demands it — mention it when you request a quote and we’ll confirm whether we can hit your timeline.
Can you deliver the GIS data in our preferred format?
Yes — tell us what format your design team works in and we’ll deliver in that. Common outputs: AutoCAD DWG (most architects and civil designers), Revit-compatible families and shared coordinates, ArchiCAD libraries, QGIS GeoPackage, ESRI Shapefile, KMZ for Google Earth. We can deliver multiple formats from the one engagement if your project team mixes software. Our in-house Trimble R2 GNSS + QGIS workflow means the data we deliver is geometrically defensible, not approximated.
Will the PAR be enough for council on its own?
No — and that’s deliberate. A PAR is a pre-design document for the architect and design team. It’s not formatted for council submission, and it doesn’t include the final Tree Protection Plan and Specification that council will ask for at DA stage. For council you need the AIA, which we develop in the second stage of the PAR → Design → AIA sequence using the PAR’s existing data plus the now-finalised design.
If your project is simple enough that you don’t need the design-stage benefit, a single-stage AIA in one go is the right call.
Do we need a PAR for a single-dwelling residential project?
Usually not. For straightforward single-dwelling sites where the trees are well-distributed, retention is clear-cut, and the design has natural room to work around the constraints, a single-stage AIA at DA-prep time is typically the right call. PARs come into their own on projects where the design itself is contested ground — subdivisions, multi-dwelling, commercial, heritage sites, architect-led work where retention is a brief outcome. If you’re not sure which path suits your project, send us the site address and the proposed scope and we’ll recommend.
What standards do you work to?
AS 4970-2025 (Protection of Trees on Development Sites — the current Australian Standard, with the updated NRZ/TPZ/SRZ terminology and three-tier encroachment classification), Arboriculture Australia Minimum Industry Standards, and IACA STAR methodology for tree retention value assessments. Our principal consultant is an AQF Level 5 Consulting Arborist and a Licensed NSW Builder — the standards work is grounded in practical site and construction experience, not just textbook compliance.
Design around the trees, not into them
Send through your project details and we’ll have a fixed-fee Preliminary Arboricultural Report quote in your inbox within 24 hours — with the spatial-data formats your design team needs.
1300 859 510 Get my PAR quote Mobile: 0434 523 566