Care of trees within development sites

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In order to assist you in the correct tree protection methods when building near trees and to help you to comply with your planning conditions, St Albans District Council has produced the following information to give you advice and guidance in caring for trees on development sites.

Trees within development sites

Trees within development sites are vulnerable to damage in two areas:

  1. The trunk and branches making up the crown of the tree can be damaged by demolition and construction vehicles.
  2. The roots are often overlooked are easily damaged by ground compaction and excavations.

Protective fencing

The position of this fencing may have already been agreed as part of the planning consent. However, if it has not, it is likely that there will be a planning condition relating to its location, which will request the location to be agreed in writing beforehand by the Local Planning Authority. 

Details of approved plans or development and related planning conditions can be viewed on our Planning Applications Search facility.

You are advised to check for approved tree protection measures and comply with related planning conditions before any materials or machinery are brought on site and before development commences. 

As a general rule, the distance for protective fencing to trees is determined by the diameter of the trunk at 1.5m above ground level multiplied by 12. For example, a tree with a trunk measuring 50cms diameter will require fences to be 6m away from its centre.

Please note this is a simplified example and advice is best sought from an arboriculturist. The Arboriculturist Association can provide details of approved arboricultural consultants and contractors via their website:

Type of fencing

An example of the type of fencing used for tree protection is shown in the download below. However, it should be a minimum of 2.3m high and use vertical and horizontal scaffolding poles with the uprights driven well into the ground and well braced to resist impact. Onto this weldmesh panels (without the use of rubber or concrete feet) should be securely fixed.  Full details of BS5837 can be purchased from BSI at

Dos and don'ts for tree protection during construction work

  • Do ensure that all trees are protected before demolition or other site works with the correct type of fencing to standard set in BS5837, 2012 and/or approved plans/planning conditions, and that this remains in position until the development is complete.
  • Do ensure that the site foreman and all staff involved in site works are informed about tree protection measures and the importance of compliance with approved plans/planning conditions.
  • Obtain arboricultural advice if difficulties occur over compliance with approved tree protection measures. Contact the Planning Case Officer before attempting to remove tree protection fencing.


  • Don’t remove or alter the protective fencing without prior agreement from the Council’s Planning Department.
  • Don’t store building materials or equipment around the base of any tree inside fenced off areas. This can cause compaction, which can kill tree roots.
  • Don’t pile soil, sand or other materials around the base of a tree. This can cause compaction, which can kill tree roots.
  • Don’t spill or mix concrete, mortar, fuel or any other potential pollutants around or near trees.
  • Don’t light fires or drive vehicles beneath the canopies of the trees on site. Driving cause’s compaction and fires can cause serious damage to the trees stem, branches and roots. 

This information is intended to provide general guidance only. If you have any further doubts about what you are required to do to comply with planning conditions relating to trees, please contact the Council’s Development Management Team on 01727 866100 or email

A downloadable version of this web page is available below.

Date of last review: 09 July 2019