Tree and Landscaping Assessment for Development Applications

The following is a plain-language guide to the landscape plans and arborist information that may be required with a development application.

At a glance:

  • Most development applications must include a landscape plan
  • A suitably qualified landscape architect or landscape designer must prepare a detailed landscape plan
  • If there are trees on the site or on neighbouring land, you must also submit an Arboricultural Impact Assessment (arborist report)
  • Read the relevant development controls before preparing your application

1. When an arborist report is required

If there are trees on the development site or on neighbouring properties, submit an Arboricultural Impact Assessment, also called an arborist report.

The report must:

  • Be prepared by a suitably qualified arborist with at least Australian Qualifications Framework Level 5 in Arboriculture
  • Comply with Australian Standard AS 4970:2025 - Protection of Trees on Development Sites

2. What the arborist report must assess

The arborist must assess the combined impacts of the whole development, including:

  • Cut and fill works
  • Retaining walls
  • Stormwater and sewerage drainage systems
  • Areas where wastewater treatment or disposal systems will be installed
  • Driveways and their associated crossovers
  • Roads
  • The creation or establishment of a bushfire asset protection zone

The report must also include the following information:

  • The species, condition, height and canopy spread of each tree
  • A site plan that clearly shows each tree
  • The Notional Root Zone (NRZ) and Structural Root Zone (SRZ) of each tree, clearly shown on the site plan
  • The amount of encroachment into each tree's NRZ and SRZ, with a discussion of the likely impacts
  • Whether each tree will be removed or retained
  • The required Tree Protection Zone (TPZ) for every tree that will be retained
  • A detailed Tree Protection Plan (TPP) and Tree Protection Specifications (TPS). These must include the construction methods to be used within the NRZ and TPZ

Address encroachment in accordance with AS 4970:2025:

  • Minor encroachment: 10% or less of the NRZ, with no intrusion into the SRZ
  • Moderate encroachment: 11% to 20% of the NRZ, with no intrusion into the SRZ. A Project Arborist must review the encroachment. More investigation may be needed to show that the tree will remain viable
  • Major encroachment: More than 20% of the NRZ, or any intrusion into the SRZ. The Project Arborist must demonstrate that the tree will remain viable. This may require non-destructive root investigation, soil analysis, and consideration of the tree's health, vigour, stability and sensitivity of the species

The report must identify impacts on trees, trees that need to be removed, and trees that can be retained after all design options have been explored

Points to Note

  • Give the arborist all plans and reports needed for the assessment
  • Give preference to retaining significant trees, trees with a long Useful Life Expectancy, and trees with high ecological value
  • Avoid impacts on neighbouring trees wherever possible. The report must recommend how trees on adjoining properties will be protected
  • Trees on adjoining properties must not be identified for removal
  • Accurately revise and update all plans and documents to reflect any required changes

3. Check the development controls

Prepare the landscape plan in line with The Hills Development Control Plan, Part C, Section 3. Development-specific or site-specific Development Control Plans may include extra requirements. View The Hills Development Control Plan here.

4. Who must prepare the landscape plan? 

A suitably qualified landscape architect or landscape designer must prepare a detailed landscape plan.

5. What the landscape plan must show

Include all of the following information:

  • Trees and other vegetation that will be retained or removed
  • Existing spot levels and contours, including levels beyond the site boundary. This must show that the relationship between the site and neighbouring properties has been considered
  • Surface finishes
  • Proposed levels
  • Retaining walls and planter boxes. Show the Top of Wall (TOW) and Bottom of Wall (BOW) heights for each wall and planter box
  • A detailed planting plan. Show each species as an individual symbol on the plan and include a plant schedule with the plant name, size and quantity
  • The proposed turf type. Kikuyu must not be used
  • A mix of trees, shrubs and groundcovers. Species must be predominantly native
  • Minimum plant container sizes: 75 litres for trees, 200 millimetres for shrubs and 150 millimetres for groundcovers
  • Proposed fence heights and materials
  • Along street frontages, set back all fences and retaining walls so there is room for planting in front of them
  • The letterbox location for each proposed dwelling
  • Landscape areas with a minimum dimension of 2 metres

6. Planting over a concrete slab

If landscaping is proposed over a slab or other concrete surface, show the minimum soil depth for every planting area and planter box.

  • Large trees: 1.2 metres
  • Medium trees: 1 metre
  • Small trees: 800 millimetres
  • Shrubs: 500 to 600 millimetres
  • Groundcovers: 300 to 450 millimetres
  • Turf: 200 millimetres

Important Note: These measurements are for soil only, not the total depth of the planter. Mounding soil to achieve the required depth is not supported.

7. Landscaping in bushfire-prone areas

Landscaping in bushfire-prone areas must comply with the Planning for Bush Fire Protection guide. See RFS Planning for Bush Fire Protection.

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