Tree removal on a development site in NSW is approved either through the DA itself or through a separate council permit, and council decides which by reading its DCP tree provisions and the vegetation chapter of State Environmental Planning Policy (Biodiversity and Conservation) 2021. For any tree of size on or near the building footprint, the DA needs an arborist report prepared to AS 4970-2009 that identifies each tree, sets its tree protection zone, and states whether it can be retained. Where native vegetation is cleared above the Biodiversity Offsets Scheme thresholds or on the Biodiversity Values Map, a Biodiversity Development Assessment Report is triggered and the project changes character. Most house and duplex DAs stay well under those thresholds, but the arborist report and a credible replanting plan decide whether council supports the removals.
Key takeaways
- Trees on private land in non-rural areas are regulated by council DCPs under Chapter 2 of the Biodiversity and Conservation SEPP; removal needs a permit or, if part of a development, approval in the DA.
- AS 4970-2009 sets the tree protection zone at 12 times the trunk diameter at breast height (minimum 2 m, maximum 15 m) and treats encroachment over 10% of that zone as major.
- The Biodiversity Offsets Scheme is triggered when native vegetation clearing exceeds an area threshold tied to the minimum lot size (0.25 ha where the minimum lot size is under 1 ha) or the site is on the Biodiversity Values Map.
- Sydney councils increasingly assess DAs against canopy cover targets and expect replacement planting at set ratios, often two or more trees for every one removed.
- Removing trees before lodging a DA to avoid the assessment is an offence under the SEPP and the DCP and is treated seriously by councils.
How a tree ends up in a DA
Chapter 2 of State Environmental Planning Policy (Biodiversity and Conservation) 2021 (Vegetation in non-rural areas) gives councils the power to regulate trees and vegetation through their DCP. Each council’s DCP then defines what a protected tree is, usually by height, trunk circumference or canopy spread, and sets out the permit process. When a tree needs to go to make room for a building, the removal is assessed as part of the DA rather than through a separate permit, and the consent condition either authorises the removal or requires retention.
Councils vary. Blacktown’s trees on private land page explains its permit process and lists the situations (heritage items, conservation areas, biodiversity areas, significant trees) where a DA is required instead. The Hills Shire Council’s trees and streetscapes pages set out its rules for pruning and removal, and The Hills DCP 2012 carries the definitions. Parramatta DCP 2023 and Cumberland DCP 2021 do the same for their areas. Read the DCP before the arborist is briefed, so the report uses the council’s thresholds.
What the arborist report must contain
An arborist report for a DA is prepared by a consulting arborist with a minimum Australian Qualifications Framework Level 5 qualification, and it follows AS 4970-2009 Protection of trees on development sites. Council officers look for:
- A tree schedule with each tree numbered on a plan: species, height, canopy spread, trunk diameter at breast height (measured at 1.4 m), age class, health, structure and a retention value (high, medium, low).
- Tree protection zones (TPZ) calculated at 12 times the trunk diameter, with the 2 m minimum and 15 m maximum, drawn as circles on the site plan.
- Structural root zones (SRZ) calculated from the trunk diameter at ground level, the area where excavation is likely to destabilise the tree.
- Encroachment analysis for every retained tree: what percentage of the TPZ the proposed works enter. Under 10% is minor; over 10% needs justification through root mapping or an alternative design.
- A recommendation for each tree: retain and protect, retain with specified measures, or remove, with reasons.
The report that gets a removal approved is the one that shows the alternatives were tested. If a Sydney blue gum on the rear boundary has a 12 m TPZ and the duplex footprint needs 30% of it, the arborist should say so and the planner should show why the footprint can’t shift. A report that simply says “remove, low retention value” for every tree on the block reads as advocacy and is discounted.
The council’s side: canopy, DCP ratios and replacement planting
Greater Sydney’s strategic plans set canopy cover targets, and councils have carried them into their DCPs and assessment practice. The measure most officers now use is the net change in canopy on the site. A DA that removes four trees and plants four tube stock seedlings is a net loss for 20 years. The way to answer that is a landscape plan with:
- Replacement trees at the DCP ratio (commonly two for one, sometimes higher for large or native trees), of a species and pot size that will reach a stated mature canopy.
- Deep soil zones that meet the DCP minimum, so the replacement trees have room to grow rather than sitting over a stormwater tank.
- Street trees retained and protected, with the driveway crossing located to keep clear of them.
- Canopy cover at maturity expressed as a percentage of the site, with the calculation shown.
In the Hills, Blacktown and Penrith, where established suburbs still carry remnant Cumberland Plain Woodland trees, the species matters as much as the size. A remnant grey box or forest red gum on a suburban lot in Kellyville, Quakers Hill or Cranebrook attracts more scrutiny than a planted exotic twice its size.
When biodiversity law takes over
The Biodiversity Conservation Act 2016 and the Biodiversity Offsets Scheme apply to local development that clears native vegetation above a threshold or on mapped land. The when the Biodiversity Offsets Scheme applies page sets out the two triggers:
| Trigger | Threshold | Effect on the DA |
|---|---|---|
| Area clearing threshold | 0.25 ha of native vegetation where the minimum lot size is under 1 ha; larger thresholds for larger minimum lot sizes | Biodiversity Development Assessment Report (BDAR) by an accredited assessor, offsets likely |
| Biodiversity Values Map | Any clearing of native vegetation on mapped land | BDAR required regardless of area |
| Below both thresholds | Small-scale clearing on unmapped land | Assessed under the DCP and the SEPP; a flora and fauna assessment may still be requested |
For a house or duplex on a suburban lot the area threshold is rarely reached, but the Biodiversity Values Map is a different matter. Lots on the edge of bushland in Wollondilly, the Hawkesbury, the Central Coast and the Hunter can be mapped even where they look like ordinary house blocks, and the map is checked in the due diligence stage, not after the architect has drawn the house. A BDAR adds months and real cost, and it changes the design conversation from “which trees” to “which part of the site”.
The order we do things in
- Check the Biodiversity Values Map, the bushfire map and the DCP tree definitions as part of due diligence.
- Brief the arborist with the DCP thresholds and a survey showing every tree, including neighbours’ trees within 5 m of the boundary and street trees.
- Test the sketch design against the TPZs before it is developed. Moving a garage 1.5 m at sketch stage saves a tree and an RFI.
- Prepare the landscape plan with replacement planting and canopy calculation at the same time as the architectural plans.
- Write the SEE section on trees around the arborist’s recommendations and the DCP objectives, with the net canopy outcome stated.
Frequently asked questions
Do I need an arborist report to remove a tree for a DA in NSW?
If the tree meets the council’s DCP definition of a protected tree, yes. The report must be prepared to AS 4970-2009 by a qualified consulting arborist and should cover every tree on the site and within reach of the works, including neighbours’ and street trees.
Can I remove trees before lodging a DA?
Only with a council permit or under an exemption in the DCP or the 10/50 code. Removing protected trees without approval is an offence, and councils can refuse to give credit for the cleared area, require replanting, and take enforcement action.
When does a DA need a Biodiversity Development Assessment Report?
When native vegetation clearing exceeds the area threshold for the site’s minimum lot size (0.25 ha where the minimum lot size is under 1 ha), or when any native vegetation is cleared on land shown on the Biodiversity Values Map. Most suburban house and duplex DAs fall below both.
Trees are one of the first constraints we check in a development due diligence report, and the arborist’s findings are written into the Statement of Environmental Effects alongside the landscape plan. If you’re planning a rebuild, duplex or small subdivision on a treed lot in the Hills or elsewhere in NSW, request a fee proposal and we’ll scope the tree and biodiversity work with the rest of the DA.