Tree Surveys and Their Purpose

Tree Surveys and Their Purpose

This page outlines how Austen Associates carry out tree surveys, why they are done, and the importance of their outcome as to how a tree protection plan is made and the site is developed.


Austen Associates have the privilege of having their own in-house arborist to conduct site visits and survey the trees on development sites before any planning gets done. This is an extremely important job, as when it comes to creating a suitable development plan for the project it is important to know whether or not a tree will need to be taken out or left in place and that those retained are in good health.  The retention of trees can be an important measure in terms of creating a nice setting for a development, as well as the fact that trees are important habitats for wildlife and are essential elements in helping to capture carbon.


The first step for the arborist is to take a quick look at a satellite image of the area to get a rough idea of where he will need to be looking in order to ensure he documents all existing trees and other large vegetation. Topographical surveys of the site that locate the position of the trees are also used to undertake the assessment.  Then the physical site inspection takes place (not much fun during the winter, as fingers can get cold measuring a tree!). Once on site the trees species, height, diameter, crown size, age, and condition are all documented as well as any extra information that may be useful to know, such as, if an ash tree had ash dieback disease. Each tree is also given a number so that they can be referred to later on in the report and the tree can also be located again on site, at development stage or otherwise.


Once all the trees are surveyed, a tree survey drawing is made to show the location and size of each tree on plan. The main purpose of a tree survey drawing is to know how many trees may affect the plan for the proposed building, but also to know which trees may cause a safety risk or act as screening to other neighbouring properties. A second drawing known as a tree protection plan is then made. This drawing uses the survey plan as well as the architects drawing in order to discover if any trees would be in the way of the proposed building footprint.  This is ascertained by developing a root protection area (RPA) for each tree and assessing whether the development encroaches into the RPA for each tree or tree group.  If this is the case, than there are several options to proceed:  the first is that the tree protection plan may be used as a guide to the architect to alter their plan to hopefully retain some more of the trees as they are a key feature in the environment and will also help to make the finished design more complete. The second option is to remove the tree or trees entirely if they  were to hinder the development of the site, for example, if the building position cannot be moved for other reasons.  Finally, tree surgery works may be recommended if the tree is in a position where its health may be partially affected by the proposed development.


After the drawings are completed, a tree report is written up which will first describe current site environment, and then what is planned on being built there before going into detail about each tree and their purpose on site such as screening, and whether or not they should be removed along with the reasons for doing so. A table is also made in this report which will give all the information for each tree with the key arboricultural characteristics given.


The tree survey is just one of the first steps that will be taken in order to feed into the design process but is also extremely important to complete as if it were not, it could cause problems later on in the design process or even halt the process altogether where there are important trees identified on a site. Please note that the arboricultural surveys and plans are done to the British standard and are completed by Eunan O’Donnell BSc Ag, Dip Hort, Arb cert, MILI, TechArborA.


Garden Design, Landscape Design, Landscape Masterplanning, Parks and Public Spaces, Residential Landscape Design, Urban Design

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