Preliminary Tree Assessment (PTA)
A preliminary tree assessment (PTA) is a comprehensive survey or assessment of trees within a designated site or parcel of land. These reports are often used in the earliest stages of development planning, prior to the development application (DA) or detailed design.
The preliminary tree assessment provides base data and information to guide the layout of the development, including opportunities to retain existing trees.
The first stage of a preliminary tree assessment comprises numbering, tagging, and collecting data for each tree within the site. The second stage of the preliminary tree assessment consists of using the data collected on site in conjunction with a site survey plan to compile a report. General information for each individual tree will include:
- Identification: Allocated number and botanical name.
- Dimensions: Tree height, canopy spread, and trunk diameter at breast height (DBH)
- Condition: Tree health, structure, and age class.
- Significance: Tree significance, useful life expectancy, and priority for retention.
- Protection zones: Tree protection zone (TPZ) and structural root zone (SRZ).
Our preliminary tree assessment report includes a tree location plan prepared using ArcGIS or AutoCAD software. The tree location plan shows the identifying number and location of each tree, the extent of the tree protection zone, and will be colour coded to reflect the retention value of each individual tree (low, medium, and high priority for retention).
Frequently Asked Questions
A preliminary tree assessment (or pre-development tree assessment) is a comprehensive survey or assessment of trees within a designated site or parcel of land. The first stage of a preliminary tree assessment comprises numbering, tagging, and collecting data for each tree within the site. The second stage of the preliminary tree assessment includes using the data collected on-site in conjunction with a site survey plan to compile a report.
A preliminary tree assessment is most effective during the earliest stages of development planning, prior to the development application (DA). The preliminary tree assessment provides base arboricultural data and information to guide the layout of the development.
A preliminary tree assessment is usually carried out prior to a development application around the same time the site survey is undertaken. It is both cost-effective and time-efficient to coordinate the site survey (surveyor) and the preliminary tree assessment (consulting arborist). If possible, the trees should be tagged and assessed by the arborist prior to the site survey. If the arborist tags and numbers the trees first, the surveyor knows exactly which trees should be included within their site survey plan and the numbering of the trees can be coordinated. If an existing tree numbering system exists this system should be used.
General information collected for each individual tree should include a tree number, botanical name, height, canopy spread, age class, tree significance, useful life expectancy, priority for retention, trunk diameter at breast height (DBH), tree protection zone (TPZ) and structural root zone (SRZ). The preliminary tree assessment should also include a tree location plan prepared using CAD or ArcGIS software. The tree location plan will show the number and location of each tree, and the extent of the tree protection zone and should be colour-coded to show the retention value for each tree (low, medium, or high priority for retention).
The information contained within a preliminary tree assessment is used by planners, architects, and designers, in conjunction with any planning controls and other legislation, to develop the design layout in such a way that trees selected for retention are provided with enough space to remain viable. The tree retention value will assist in prioritising which trees should be retained and protected, while the tree protection zone will provide the necessary offsets to protect those individual trees.
Tree Survey will carry out the site inspection and prepare the Arborist Report within 14 days following acceptance of the quote. This timeframe can be reduced to 7 days (priority service) for a +25% increase in the quoted fee.
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Tree Protection Plan (TPP)
A tree protection plan (TPP) generally follows the arboricultural impact assessment (AIA). The tree protection plan provides details on tree protection mitigations for trees that are proposed to be retained (as determined by the arboricultural impact assessment).
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Tree Risk Assessment (TRA)
A tree risk assessment (TRA) is a detailed analysis of the risk posed by a single tree or group of trees within a specific site. Tree risk assessments are often carried out at schools, universities, holiday resorts, parks, and other public spaces where trees have the potential to cause harm to the persons who occupy that space.
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Arboricultural Impact Assessment (AIA
An arboricultural impact assessment (AIA) is a detailed and comprehensive report that reflects the potential impacts of development on trees within and adjacent to a proposed development site.
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Tree Surveys
A tree survey (TS) is a comprehensive assessment of a specified tree population. A tree survey is typically undertaken with the aim of providing base data on the existing tree population to assist in the management and future planning around those trees.
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Project Arborist Services
The project arborist is responsible for carrying out the inspections, supervision, monitoring, and certification of trees during a development project. Details of the project arborist are often required to be submitted to the consent authority prior to construction.
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GIS and Spatial Analysis
A geographic information system (GIS) is a conceptualised framework that provides the ability to capture and analyse spatial and geographic data.
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Tree Database
A tree database or register is a means to store, retrieve, display, sort, and summarise data (information) that relate to tree assets. This can be an important and useful tool to assist and the planning, management, and maintenance of large tree populations. Our expertise in geographic information systems (GIS) allows us to create, manage and maintain large data sets with extreme precision and attention to detail.
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Tree Management Plan (TMP)
A tree management plan (TMP) is a comprehensive survey or assessment of trees within a designated site or parcel of land. These reports are often used to guide the future use, management, and maintenance of a site. The tree management plan provides base data and information, including the existing health and condition of the trees and any risks that the trees may pose.