Protecting Trees During Building Works
Trees are highly vulnerable during construction. Damage to roots, trunks, or branches — even if accidental — can cause long-term decline or death. To prevent this, trees must be protected in accordance with BS 5837:2012, the British Standard for trees and construction.
This page sets out the key measures required to safeguard trees on and around development sites.
1. Root Protection Area (RPA)
Each retained tree has a Root Protection Area (RPA), usually shown on site plans as a circle or polygon around the tree.
The RPA defines where the roots are most vulnerable.
No excavation, compaction, or storage of materials should take place within this area unless specifically approved and supervised by an arboricultural specialist.
2. Protective Fencing
Barrier fencing must be installed before any site works begin.
Fencing should:
Be fit-for-purpose, rigid, and immovable (e.g. welded mesh panels, such as “Heras”-type fencing, on a scaffold frame).
Be at least 2.3 m high.
Be secured to the ground to prevent displacement by site machinery.
Fencing should carry “Tree Protection Area – Keep Out” signs at regular intervals.
The protected area inside the fence must be treated as sacrosanct — no storage, tipping, parking, or washing-out.
3. Ground Protection
Where access within or close to the RPA is unavoidable:
Install temporary ground protection to prevent compaction.
Acceptable solutions include:
Plywood or timber boards over a compressible layer (e.g. woodchip).
Proprietary interlocking ground protection systems.
Ground protection must be designed to bear the expected loads of vehicles or machinery.
4. Coverings for Trunks and Branches
If there is risk of accidental impact from machinery, trunks may be wrapped with hessian under chestnut paling or similar material.
Do not use materials that restrict airflow (e.g. plastic or polythene sheeting).
Low branches within reach of plant should be temporarily tied back or protected with padding.
5. Site Rules
Tree protection must be in place before demolition, excavation, or material delivery.
Barriers and ground protection must remain in place for the entire duration of the works.
Works within or close to RPAs (excavation, trenching, installation of services) must only proceed under arboricultural supervision with methods such as air-spading or hand digging.
No fires, fuel storage, cement mixing, or chemical wash-out within 10 m of a protected tree.
6. Monitoring and Maintenance
The protective measures must be inspected regularly by the site manager.
Any breaches or accidental damage should be reported immediately to the project arboriculturist and the local planning authority.
Barriers must not be moved or altered without written approval.
Summary
Protecting trees during building works is not optional — it is a planning requirement and a duty of care under BS 5837:2012. Proper fencing, coverings, and ground protection preserve tree health, safeguard long-term amenity, and ensure compliance with planning conditions.
Failure to follow these standards may result in enforcement action, delays, and significant costs.