If you’re planning an extension, a new house or a larger development in Surrey or Sussex and there are trees on or near the site, the council will almost certainly want to see a tree survey before it can validate your planning application. That survey needs to follow British Standard BS 5837. This guide explains what a BS 5837 tree survey is, when you need one, what the report includes, roughly what it costs and how to avoid it holding up your application.
What is a BS 5837 tree survey?
BS 5837:2012 Trees in relation to design, demolition and construction is the British Standard that planning authorities use to make sure trees are properly considered when land is developed. A BS 5837 tree survey (sometimes called an arboricultural survey or a pre-development tree survey) records every significant tree that could be affected by the work and assesses its quality, health and value.
The idea is simple: find out which trees are worth keeping before the site layout is fixed, so the design can work around them rather than the trees being an afterthought.
When do you need a tree survey for planning?
You’re likely to need one if:
- There are trees on the site itself
- There are trees on neighbouring land close to the boundary, whose roots or canopy reach into the site
- Any trees on or near the site are protected by a Tree Preservation Order (TPO) or are in a conservation area
- Your plans include new access, driveways, drainage, services or level changes near trees
Councils across Surrey and Sussex, including Mole Valley and Reigate & Banstead, will expect tree information where trees could be affected. Submitting without it is a common reason for an application being delayed or returned as invalid. If you’re not sure, it’s worth asking us or your planning agent early. Our guide on whether you need permission to cut down a tree explains how to check whether a tree is protected.
What does a BS 5837 tree survey include?
A full survey to BS 5837 usually covers:
- A tree schedule: every tree (and relevant group or hedge) is tagged or numbered and recorded with its species, height, stem diameter, crown spread, age class, condition and estimated remaining life.
- Tree categories: each tree is graded A (high quality), B (moderate quality), C (low quality) or U (unsuitable for retention, for example dead or dangerous). The category tells the planners and your designer how much weight to give it.
- Root protection areas (RPAs): the minimum area around each tree that needs protecting during construction. It’s calculated from the stem diameter, roughly a radius of 12 times the trunk diameter measured at 1.5m.
- A tree constraints plan: a drawing that overlays the trees, their canopies and their RPAs on your site plan, so your architect can see exactly where they can and can’t build.
Arboricultural impact assessment and method statement
Once your layout is drawn up, the council will often ask for two further documents:
- Arboricultural impact assessment (AIA): looks at your proposed design and sets out which trees would be removed, which would be retained and how any impacts can be reduced or offset with new planting.
- Arboricultural method statement (AMS) and tree protection plan (TPP): explains how retained trees will be protected on site, for example protective fencing, ground protection, no-dig construction near roots and how services will be routed.
Not every application needs all of these. A small extension with one tree nearby may only need a short survey and protection plan; a housing site with mature hedgerows will need the full set. We’ll tell you what’s proportionate for your project.
How much does a BS 5837 tree survey cost?
The cost depends mainly on how many trees there are, how big the site is and which reports you need. As a rough national guide:
- Small domestic site with a handful of trees: often a few hundred pounds for the survey and tree constraints plan
- Larger sites or many trees: priced on the number of trees and time on site
- Arboricultural impact assessment and method statement: usually quoted separately once the layout is known
For an accurate price, send us your site address, a site plan if you have one and a brief description of what you’re planning, and we’ll give you a fixed quote.
When is the best time to get a tree survey?
As early as possible, ideally before your architect starts drawing. Commissioning the survey first means the design can work around the best trees from the start, which is far cheaper than redesigning later or having an application refused.
Surveys can be carried out at any time of year. Winter can actually be a good time, because the structure of each tree is easier to see with the leaves off.
Why use a local arborist?
A survey carried out by someone who knows the trees, soils and planning teams in Surrey and Sussex is easier for you to act on. Our arboricultural consultancy team have extensive experience of working with local planning authorities, with clear, targeted reports and planning application support across Dorking, Reigate and beyond. Because we’re also working tree surgeons, we can carry out any approved tree work too.
If you just need a tree checked for safety rather than for planning, our article on what a tree surgeon looks for during a tree inspection explains how that works.
FAQs
Do I need a tree survey for a house extension?
If there are trees within falling distance of the work, or whose roots or branches could be affected by foundations, scaffolding, access or drainage, the council will usually expect one. A small extension often only needs a short, proportionate survey.
Who can carry out a BS 5837 tree survey?
It should be carried out by a suitably qualified and experienced arboriculturist. The council’s tree officer will check that the survey follows the British Standard.
What do the A, B, C and U tree categories mean?
Category A trees are high quality and should be retained wherever possible. B trees are of moderate quality, C trees are low quality and U trees are unsuitable for retention, for example because they are dead, dying or dangerous.
Can I remove trees before I apply for planning?
Be careful. Removing trees before an application can count against you, and if a tree is protected by a TPO or is in a conservation area you’ll need consent first. Our guide on whether you need permission to cut down a tree explains the rules.
How long does a tree survey take?
Most domestic surveys take a single site visit, with the report following shortly afterwards. Larger sites take longer. We’ll give you a timescale when we quote.
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Get a quote for a tree survey
If you’re planning building work near trees, contact South East Tree Surgeons for a free, no-obligation quote. Send us the site address and a rough idea of what you’re planning, and we’ll let you know what survey you need and what it will cost.