Planning - BS5837

Under current planning legislation, trees are a material consideration in the planning process. Local planning authorities can reasonably expect developers to provide information on the impact of their planned construction upon trees if present on or near their development site.

Many homeowners receive a request for a 'tree survey' or BS5837 survey' in response to an initial planning submission. BS5837 refers to the British Standard Trees in relation to design, demolition and construction – Recommendations (2012) which outlines the information required in a tree survey for planning applications. A BS5837 survey is typically divided into three stages.

Stage 1 -Tree survey

This stage ideally takes place before designing the proposed development so that the results of the survey can be used to inform the design process and help determine which trees should be retained or removed. Typically the survey covers trees within the development site but might also include trees outside the site boundaries in some cases.

Tree Schedule

Each tree or tree group is given a unique reference number and is assessed against criteria outlined in BS5837 and is assigned a Category (A, B, C or U) as a reflection of its value and suitability for retention. Tree age, physiological/structural condition and remaining lifespan are factors in the categorisation process. Basic measurements such as height, stem diameter at 1.5m above ground level and crown spread are also taken to help inform the design process. The results of the assessment are presented in a schedule and the tree locations shown on a site plan.

Tree Constraints Plan

The survey results are also used to produce a plan illustrating the constraints posed by the trees upon the development. These typically comprise the crown spread of the trees, the area covered by their roots (Root Preservation Area) and the area of ground shaded by them.

Stage 2 - Arboricultural Impact Assessment (AIA)

Once a design has been settled upon, it is necessary to provide an assessment of the impact of the proposed development upon the trees. This includes identification of trees to be removed and retained and an outline of any measures required to avoid or mitigate damage to them during the construction phase. Common issues are; prevention of root compaction from heavy machinery and material storage during construction through ground protection measures or exclusion zones; mitigation of tree loss through a planting scheme and avoidance of damage to tree branches through proactive 'facilitation pruning'.

With many smaller or simpler developments such as home extensions or the construction of outbuildings, Stages 1 and 2 are often carried out together.

Stage 3 - Arboricultural Method Statement (AMS)

The AMS outlines in detail the methodologies that must be used on the site by the builder in order to protect retained trees from harm. This is generally only required on larger or more complex developments where significant harm to trees is likely during construction. Sometimes attendance of an arboriculturalist on site may be required to insure that the AMS is followed.

Further information