Also known as pre-development tree assessment, a Preliminary Tree Assessment or PTA is a survey of trees on a specific site or within a designated area. Preliminary tree assessments provide an ample amount of information about the trees. The survey aims to extract data on the dimensions, health, origin, species, and structure of the trees.
After completing the assessment, the team identifies if the trees are worth and appropriate for redevelopment. Furthermore, the preliminary tree assessment allocates Tree Protection Zones (TPZs) to make sure that the roots of trees aren’t compromised during construction work.
Preliminary tree assessments consist of the following two steps:
The first stage of any preliminary tree assessment consists of collecting data. The team thoroughly tags and marks the trees with numbers. Each tree goes through a complete evaluation.
The collected data is used to prepare a report in partnership with the site survey plan. All the findings of the preliminary tree assessment are sketched, and a grand report is created. Some teams also write down their recommendations according to the results of the preliminary tree assessment.
A typical preliminary tree assessment will have a tree location plan prepared using ArcGIS or CAD. The plan will feature the number and location of each tree, the area of the tree protection zone, and the colour-coded retention value for every tree.
In a preliminary tree assessment report, you’ll find the following general information about each individual tree: structural root zone, tree protection zone, height, age class, useful life expectancy, trunk diameter at breast height, tree number, botanical name, canopy spread, and true significance.
The information brought to life by a preliminary tree assessment is used by designers, architects, and planners. They use the assessment and their custom plan to pursue their task in such a way that the trees remain protected. The tree retention values will assist them in prioritising which trees should be protected and retained. Furthermore, the tree protection zone will help the team to make the necessary efforts to safeguard the trees.
The most practical time to carry out a preliminary tree assessment is during the earliest stages of development planning. Ideally, PTAs will occur before the development application (DA) is completed, or shortly after. The assessment provides base arboricultural data and information that help development teams guide the layout of the development.
Most preliminary tree assessment companies take about two weeks to inspect the site and prepare the final report. However, if you want to speed things up, some companies can complete a full assessment job in a week or so, usually at an increased price.
Although the time frame for preparing a preliminary tree assessment varies from company to company, the majority quote in the 14-day range.