British Standards
A tree survey of the construction site must be completed in accordance with British Standard (BS) 5837 ‘Trees in relation to design, demolition and construction’ prior to preparing site designs and layouts. The survey should include details of both the site and individual trees and should provide the following information.
Site survey
Site surveys should include:
- The location and identification of all trees, shrubs and hedges.
- Other relevant site features such as watercourses, service runs, hard surfaces etc.
- Details of ground levels as a basis for avoiding changes to soil levels around retained trees.
- Locations of trees on adjoining land which might be affected by the works.
- Details of site drainage which may be altered or interrupted by the proposed works and which may, as a result affect retained trees.
- Site features with a nature-conservation value.
Tree survey
- Tree surveys should include:
- The general health, vigour and condition of each tree including details of structural defects.
- An assessment of life expectancy of each tree.
- The dimensions and form of each tree including accurate details of the position and shape of its crown in relation to the proposed new site layout.
- Details of other site features such as service runs and how close they are to the trees.
- How suitable each tree is for retention within the completed development or works.
- Any tree surgery or other maintenance work required.
- Any existing tree-preservation orders or conservation-area status.
- Root Protection Area of each tree to be retained.
- Other pertinent information e.g. memorial or historic values
Detailed information on the species, health, condition and status of each tree must be collected and assessed by an appropriately qualified and experienced arboriculturalist.
Trees within the development site must be assessed in accordance with the recommendations included in British Standard (BS) 5837 ‘Trees in relation to design, demolition and construction’. The assessment covers their condition, significance, and landscape and environmental value. The tree survey should classify each tree into the retention category of the British Standard.
Please refer to BS5837:2012 Table 1 – Cascade chart for tree quality
Safety
Where there is a conflict between retaining a category A or B tree (see the link above) and ensuring road safety, the first option should be to amend the proposed design to avoid the conflict and retain the tree. The council will consider situations where it is not reasonable or practical to do this on a site-by-site basis.