If you’re planning building work near trees in the UK, a BS5837 tree survey is often the first arboricultural document your planner or architect will ask for.
What is BS5837 and why does it matter?
BS5837:2012 is the British Standard that sets out how trees should be considered during design, demolition and construction.
It aims to make sure development and trees can coexist safely, without avoidable damage to either.
For planning, trees are a “material consideration”, so councils expect applications to follow BS5837 where trees are on or near the site.
When do you need a BS5837 tree survey?
You typically need a BS5837 survey when:
- You are applying for planning permission and there are trees on or close to the site.
- You plan extensions, new builds or access changes within the likely root spread or canopy spread of trees.
- Trees are protected by a Tree Preservation Order or lie in a Conservation Area.
Even if planning permission is not required, the standard still applies as good practice for building near trees.
What does a BS5837 tree survey include?
A BS5837 survey is carried out by an arboriculturist and is based on a measured topographical plan of the site.
Each tree or group is recorded in a schedule and plotted on a plan with its canopy spread and root protection area (RPA).
Typical survey data includes:
- Tree number and species (usually by common name).
- Height, stem diameter, crown spread and ground clearance.
- Life stage and condition, with notes on defects or decay.
- An estimated remaining contribution (10, 20, 40+ years).
- A BS5837 category grade (U, A, B or C).
The grade gives a quick visual of which trees are most important to try to retain.
Understanding BS5837 tree categories
BS5837 uses a colour‑coded system to show tree quality and retention value.
| Category | Colour on plans | Meaning (plain English) | Typical decision | Source |
|---|---|---|---|---|
| A | Light green | High quality, 40+ years life, key visual or conservation value. | Strong presumption for retention, design usually works around these trees. | |
| B | Mid blue | Good/moderate quality, 20+ years life, or important as part of a group. | Desirable to retain where practicable; often integrated with some compromise. | |
| C | Grey | Low quality or young trees with limited current value; 10+ years life. | Can be removed if needed to facilitate sensible design; often replaced with new planting. | |
| U | Dark red | Poor condition or unsafe; not realistically retainable beyond 10 years. | Recommended for removal on safety or management grounds. | |
These categories help planners and designers judge which trees are genuine constraints and which can reasonably be removed or replaced.
Root Protection Areas (RPAs) in simple terms
The RPA is the minimum area around a tree that should be kept undisturbed to protect its roots and soil.
For a single‑stem tree, the radius is calculated as 12 times the stem diameter, with values tabulated for common sizes.
Key points:
- RPAs are first drawn as circles on the plan, then can be adjusted to reflect actual root patterns where justified.
- As a rule, new buildings should sit outside RPAs; if work inside is unavoidable, specialist design and mitigation are needed.
- Cumulative intrusions into the RPA (e.g. repeated trenches for services) can be very damaging and should be avoided.
The RPA becomes the basis for the construction exclusion zone on site.
Basic do’s and don’ts near trees
If you are planning or starting works near trees, BS5837 promotes some straightforward principles.
Do:
- Get the tree survey done early and share it with your architect/engineer.
- Design layouts around good A and B category trees wherever possible.
- Erect tree protection fencing before main works and keep it in place.
- Use suitable ground protection where temporary access is essential within RPAs.
Don’t:
- Trench, lower or raise levels in RPAs without arboricultural input.
- Store materials, mix concrete, or park consistently within protection zones.
- Assume existing mature trees will “just cope” with drastic changes in ground conditions; they often decline over several years.
New planting and long‑term tree management
BS5837 is not only about existing trees; it also guides new planting so today’s saplings don’t become tomorrow’s problems.
- New trees should have enough space from buildings, walls and services to avoid direct damage as they grow, with typical minimum distances set out in a table.
- On shrinkable clay soils, foundation design and planting design should be coordinated to manage subsidence and heave risks.
- Newly planted trees should be maintained for at least the first 3–5 years, including watering, weed control, checking stakes and formative pruning.
For retained trees, the standard recommends a post‑development management plan with periodic inspections and remedial works as needed. Get in touch with us today about getting your BS5837 tree survey.
