Development Tree Compliance Guide – Newcastle NSW

The AIA is the technical foundation of DA approval where trees are affected.

An AIA includes:

• Tree identification, species and condition assessment, all trees on and within 3m of the boundary
• Retention value and structural condition analysis
• TPZ and SRZ calculations under AS4970-2009, mapped directly against architectural drawings
• Development impact assessment, encroachment classification (minor, moderate, major)
• Tree retention vs removal justification, Urban Forest Technical Manual Part A Section 3.4.4
• Heritage Conservation Area flags, Heritage Minor Works requirements identified
• Biodiversity Conservation SEPP 2021 and native vegetation triggers identified and managed
• Council-ready documentation formatted for DA submission

Reports not aligned to architectural plans, or missing DCP 2023 Urban Forest Technical Manual requirements, are the most common cause of RFIs from Newcastle City Council.

Newcastle City Council applies a retention-first principle under DCP 2023. Retention must be demonstrated before removal is considered.

The AIA must document:

• Which trees can be retained within the proposed development design
• What design alternatives were considered to avoid or minimise tree removal
• Why retention is not feasible for trees proposed for removal, with evidence
• Which Urban Forest Technical Manual Part A Section 3.4.4 removal test applies and why

If retention is feasible, removal will not be supported, regardless of design preference. The four removal tests, infrastructure works, development, risk assessment and amenity, must each be addressed with evidence, not assertion.

Soil conditions are assessed on functional performance, not just dimensions.

DCP 2023 Section C12 requires consolidated deep soil zones of adequate dimensions to support the retention and planting of large and medium canopy trees.

Council expects:

• Adequate soil volume and depth to support long-term root growth
• Uncompacted natural soil, no subbase, fill or compacted material
• Continuous planting zones without structural interruption
• Root expansion capacity without conflict with services and structures

Newcastle soil context affects what is achievable by area:

• Reactive clay soils (Adamstown, New Lambton, Kotara, Waratah), moderate to high reactivity, adequate where uncompacted and of sufficient depth
• Sandy loam over Permian sedimentary rock (Cooks Hill, Hamilton, Newcastle East), moderate depth, good drainage, lateral root spread common
• Alluvial flats (Fletcher, Maryland, Shortland, Hexham), variable depth and reactivity, high water table in parts
• Sandy coastal soils (Stockton, Merewether, Bar Beach), free-draining, good for root expansion, lower nutrient retention

Inadequate soil design is one of the most common reasons landscape plans require revision at DA stage.

AS4970-2009 governs how close construction can occur to retained trees and defines the protection requirements throughout the construction period. Newcastle City Council applies AS4970-2009, not the updated 2025 standard.

Tree Protection Zone (TPZ)

The protected area around a tree, calculated from trunk diameter at 1.4m above ground. No construction, soil disturbance, storage or machinery access without arborist approval.

Structural Root Zone (SRZ)

The core root zone required for tree stability. Any SRZ encroachment requires direct root evidence and design alternatives before Council will approve.

Encroachment Classifications

• Minor, outside SRZ, less than 10% of TPZ: generally supportable with standard protection
• Moderate, 10 to 20% of TPZ, outside SRZ: requires arborist-led design review
• Major, more than 20% of TPZ, or any SRZ encroachment: design alternatives required, root investigation commonly needed

Tree protection during construction:

• TPZ fencing established and verified before any works commence
• No storage, vehicle access or machinery compaction within TPZ
• Root-sensitive excavation methods where required, AirSpade and hand excavation
• Arborist supervision at key construction stages

These requirements are enforced as DA conditions. Non-compliance is a breach, penalties up to $1.1 million in the NSW Land and Environment Court.

A Tree Protection Plan or Tree Management Plan is the enforceable document specifying how trees will be protected during construction. Newcastle City Council commonly requires a TPP as a condition of DA approval.

TPPs include:

• TPZ fencing layout and specification, AS4970-2009 compliant
• Ground protection measures and exclusion zones
• Approved access and construction zones
• No-go areas for excavation and storage
• Required arborist supervision stages
• Final certification requirements for occupation certificate

A TPP prepared but not implemented on site is a DA condition breach. The consequences fall on the developer, not the arborist.

A Project Arborist manages tree compliance across the full development lifecycle, from pre-design survey through to occupation certificate certification. Because our Project Arborist is the same AQF Level 5 arborist who prepared the AIA, there is no handoff and no knowledge gap between the report and the site.

Services include:

• Pre-design advice and TPZ and SRZ constraint mapping
• AIA for DA or CDC, written by the Project Arborist
• Council RFI response, the report author responds directly
• TPP preparation and implementation oversight
• Construction stage site inspections and supervision
• Encroachment assessment and root investigation
• Final arborist certification for Council occupation certificate conditions

Engaging the same arborist from planning through to certification ensures consistency and eliminates compliance gaps.

Used where tree retention or removal decisions cannot be made from standard above-ground assessment.

Services include:

• AirSpade non-destructive root excavation and mapping
• TPZ and SRZ confirmation against proposed works, AS4970-2009
• Structural root plate identification and stability assessment
• CAD-integrated root mapping against architectural drawings

Root investigation is increasingly required on Newcastle development sites, particularly in the western suburbs where large Brush Box and eucalypts on reactive clay soils have SRZ extents that regularly exceed lot boundaries.