Preliminary Tree
Assessment

What is a Preliminary Tree Assessment?

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.

When should a Preliminary Tree Assessment be carried out?

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.

What does the Preliminary Tree Assessment need to be co-ordinated with?

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 co-ordinate 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 numbering of the trees can be co-ordinated. If an existing tree numbering system exists this system should be used.

What sort of information is included within a Preliminary Tree Assessment?

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, 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.

How long does it take to prepare a Preliminary Tree Assessment?

Tree Survey will carry out the site inspection and prepare the report within 14 days following acceptance of the quote. This time frame can be reduced to 7 days (priority service) for a +25% increase in the quoted fee.