You may need to provide Council with information on how you will protect trees during development and how your development will affect Council-owned or private Regulated and/or Significant trees. This document provides answers to common questions about tree protection during development to assist with your project.
All publicly and privately owned Regulated and Significant trees require protection under State Legislation. Recent changes to legislation mean that any tree with a circumference of 1 metre or more – when measured 1 metre above ground level is now a regulated tree and subject to development controls. For more information on trees protected by law, including any exemptions, please visit the Plan SA website.
Council street trees that are unregulated also require protection when in proximity to any form of construction, which may include but is not limited to driveways, paths, verge modification and fences. Please contact Councils Customer Experience Team on 8366 4200 for preliminary advice before applying to undertake works on Council land or intending to carry out development. All Council trees are protected under the Local Government Act 1999 and must be protected.
The property owner and all workers on site are responsible for protecting both Council and legally protected private trees during the entire development project. Any tree that could be affected by the development must be included in the site plans submitted with the application. This applies to applications for land subdivision, building alterations, new dwellings, and any other development activities. This also includes development activities which may not require development approval, such as low fencing, retaining walls and verge landscaping.
You should seek advice from a minimum Level 5 (Diploma) qualified arborist to determine the legislative status of the trees, and to assess the possible impacts of your proposed development activities. If you have any concerns that a Council tree may be impacted, you may contact our Customer Experience Team on 8366 4200 to lodge a request for preliminary development advice from the Urban Forest Team.
A Tree Protection Zone (TPZ) is an area around a tree that is designated to protect its roots, trunk, and overall health during construction or development activities. It is intended to prevent damage to the tree from activities such as digging, trenching, or heavy machinery use that could negatively impact trees. The size of the TPZ is determined by the tree's diameter at breast height (DBH) and includes the tree’s structural root zone (SRZ). Ensuring the SRZ remains undisturbed will reduce any increased instability with the trees structure, and therefore its risk to the public and the property owner.
Activities prohibited in the TPZ include, but are not limited to:
- Alteration of soil levels including excavation, cut and fill.
- Mechanical trenching for building footings, fences or the installation of underground services (Power, Gas, Stormwater).
- Stockpiling of building materials, equipment, rubble and tools.
- Vehicle movements including machinery.
- Sealing of surfaces with impermeable materials.
In some cases, 'tree-sensitive' construction methods can be used within the Tree Protection Zone (TPZ). These methods should be discussed with a qualified arborist to ensure the methods meet Australian Standard "AS 4970-2009 Protection of Trees on Development Sites."
Council highly recommends contacting a qualified level 5 Arborist for peace of mind, or alternatively, contact our Customer Experience Team on 8366 4200 for advice on Council owned trees.
The Planning, Development & Infrastructure Act 2016 describes tree damaging activity as:
- Tree removal
- Killing or destruction
- Branch or limb lopping
- Ringbarking or topping
- any substantial damage to the tree, including to its root system.
Failure to protect Regulated or Significant trees from development may result in tree damaging activity and a fine of up to $120,000 and a criminal conviction may apply under the Planning, Development & Infrastructure Act 2016. To avoid any wrongdoing, it is always best practice to engage a qualified level 5 Arborist for advice.
Trees on Council verges and reserves that are not protected by the Planning, Development & Infrastructure Act 2016 are protected under the Local Government Act 1999. Undertaking a Tree Damaging Activity on any Council tree can result in a $5000 fine and criminal conviction.
Examples are provided below showing a range of activities observed throughout the city that are deemed a tree damaging activity.
Severed roots and soil level changes in TPZ.
Storage of building materials within the TPZ.
Tree protection should begin at the design stage of your project. It is important to engage a qualified level 5 arborist early on to ensure your project runs smoothly and on time. If needed, an Arboricultural Impact Assessment should be undertaken to identify and document any potential tree damage that could result from the development design.
An Arboricultural Impact Assessment should include the following:
- Tree Survey: Details of all trees on-site (species, size, health, and legislative status).
- Tree Protection Plan: A Plan to protect trees during construction (TPZ fencing, Tree Sensitive excavation, Tree sensitive design and construction). All trees on site must be mapped on a site plan.
- Development Impact: How the development will affect trees (removal, pruning, or root damage from excavation including root compaction and installation impermeable surfaces).
- Post-Construction Care: Ongoing tree maintenance after construction.
- Requirement for a certificate of compliance throughout multiple stages of the development, which is signed off by the project arborist.
The Arboricultural Impact Assessment should meet the requirements as prescribed within the Australian Standard: AS 4970-2009 Protection of trees on development sites.