Choosing an arboriculturist for a BS 5837 tree survey
A BS 5837 survey is about whether your scheme can be built without damaging retained roots. Here is how to choose the consultant and check what they produce.
If your council has asked for a tree survey, it wants a report prepared to BS 5837:2012, and it wants it written by someone who knows how to apply that standard to a construction project. Not a tree surgeon who will quote for the felling. Not the landscape designer. An arboricultural consultant.
The distinction matters because the survey is not really about the trees. It is about whether your extension, driveway or new house can be built without damaging roots the council has decided are worth keeping.
What the standard expects of the surveyor
BS 5837:2012 sets out how trees should be surveyed, categorised and protected in relation to design, demolition and construction. It asks the surveyor to record, for each tree, the species, height, stem diameter measured at a set height, crown spread in four directions, crown clearance, age class, physiological and structural condition, preliminary management recommendations and an estimate of how many years of useful contribution the tree has left.
Each tree is then placed in a retention category. In outline: U for trees that should be removed regardless of the development, and A, B and C in descending order of quality and value, with sub-categories distinguishing arboricultural, landscape and cultural value.
From the stem diameter comes the root protection area, a circle around the tree within which the roots are assumed to need protecting. The calculation is set out in the standard and is capped for very large trees. Nearly every dispute about a scheme comes down to whether construction encroaches on a root protection area and, if so, whether the method proposed is acceptable.
A surveyor who cannot explain the categories and the root protection area in plain terms is not the right surveyor.
Registration schemes and what they verify
Two things are worth asking for, and they are different.
The Arboricultural Association operates a registered consultant scheme. Entry involves assessment of the individual's work, including report writing, and registration is periodically reviewed. It is the most direct evidence that someone can produce a report to the standard rather than simply climb a tree.
Chartered status through the Institute of Chartered Foresters is the other recognised route, with Chartered Arboriculturist as the relevant designation.
Note what a scheme does not tell you. Approved contractor status relates to tree work businesses, which is a different service from consultancy. Insurance certificates tell you about cover, not competence. And a long list of qualifications is not the same as recent experience of planning applications in your type of setting.
Ask three questions: which registration or chartered status the individual personally holds, how many BS 5837 reports they produced in the last year, and whether they have worked with your local authority's tree officer before. The professional directory is one route to a consultant who can also review a draft before it is submitted.
Three documents, not one
A tree survey is often quoted as a single item when the planning submission needs up to four.
- The tree survey itself, a schedule of every tree on and adjacent to the site, with a plan showing positions, canopies and root protection areas.
- An arboricultural impact assessment, which takes the proposed layout and works out what it does to the trees: removals, pruning, encroachment into root protection areas and effects during construction.
- An arboricultural method statement, setting out how the retained trees will be protected during demolition and construction, including any special engineering such as no-dig surfacing.
- A tree protection plan, a drawing showing the barriers, the ground protection and the construction exclusion zone.
Councils commonly condition the second, third and fourth even if they only asked for the first. Get a fee proposal that prices all four, with the later ones as a provisional item if the layout is not fixed.
Checking the schedule for quality
You do not need to be an arboriculturist to spot a weak report.
Look for stem diameters recorded to the millimetre rather than rounded, which indicates actual measurement. Look for a date of survey and a note of the season, because a survey of a deciduous tree in January cannot comment properly on foliage condition. Look for individual comments on individual trees rather than the same sentence repeated down the column.
Check that trees on neighbouring land whose canopies or roots reach into your site are included. They are frequently the ones that constrain a layout, and omitting them is the most common defect.
Check that the root protection areas on the plan are drawn, not assumed, and that where a circle has been offset because of an obstruction such as a wall or a road, the report explains why.
And check the report actually looks at your scheme. An impact assessment that describes the site without ever mentioning the proposed building footprint is a survey with a different cover page.
Independence when a tree is coming out
If your proposal requires a tree to be removed, do not commission the report from the company that will quote for removing it. The conflict is obvious to a tree officer and it undermines the report before anyone reads the content.
The same applies in reverse where a neighbour has objected. A report that reads as advocacy carries less weight than one that concedes the honest point and then explains why the scheme is still acceptable. Our note on independence and conflicts of interest in planning evidence sets out how officers read these documents.
Where a tree is protected by a Tree Preservation Order, or stands in a conservation area, removal or pruning needs separate consent or notice regardless of the planning application, and an application to fell a protected tree needs its own justification.
What drives the fee
Four things, mostly.
The number of trees and whether they are individuals, groups or hedgerows. A site with 12 individual trees costs more to survey than a site with a single group of 40 similar specimens.
Whether a topographical survey exists. Trees have to be plotted accurately, and if there is no topographical survey the consultant either does the plotting or waits.
How many of the four documents you need, and whether the layout is settled. Producing an impact assessment against a design that then changes means doing it twice.
Access and site conditions. A brambled back garden with no rear access takes longer than an open plot.
Most household schemes fall in a range a consultant will quote against a scope. Ask for a fixed fee against a written scope rather than a day rate, and ask what a revision costs if the design changes.
Instructions that avoid a second visit
Send the following with your instruction, and the consultant should not need to come back.
A topographical survey with levels and existing features. The draft site layout, even if it is provisional, with the building footprint and the driveway. Existing and proposed drainage runs, because drainage trenches through a root protection area are a frequent cause of refusal. Any known constraints such as a Tree Preservation Order reference or conservation area status. The council's pre-application response if you have one. And the name of the case officer.
Then ask for the report in a form the council can use: a schedule in a table, plans at a stated scale, and a clear statement of which trees are removed, which are retained and what protection each retained tree gets.
Councils normally expect a BS 5837 survey and impact assessment to be written by a suitably qualified arboriculturist, and professional review is strongly advised before submission. Our guidance on writing a brief for a specialist planning report covers the rest of the instruction.
This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it.
Enter your postcode on PlanScope to see which documents a scheme with trees on site is likely to need. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.
Frequently asked questions
Is a tree surgeon the same as an arboricultural consultant?
No. A tree surgeon carries out tree work; a consultant surveys, categorises and reports on trees in relation to development. Approved contractor schemes cover the first, while registered consultant and chartered arboriculturist status cover the second. For a planning application you need the consultant, and ideally one who does not also quote for the felling.
What is a root protection area?
A notional circle around a tree within which roots are assumed to need protection, calculated from the stem diameter using the formula in BS 5837:2012 and capped for very large trees. Where an obstruction such as a wall or road prevents roots growing in one direction, the area can be reshaped, but the report must explain the reasoning.
Do I need more than a tree survey?
Usually. Councils commonly require an arboricultural impact assessment of the proposed layout, an arboricultural method statement for construction, and a tree protection plan showing barriers and exclusion zones. Ask for a fee proposal covering all four, with the later documents priced provisionally if the layout is not yet settled.
Can trees on a neighbour's land affect my application?
Yes, frequently. Canopies overhanging the boundary and roots extending into your site both constrain what can be built, and their root protection areas must appear on the plan. Omitting neighbouring trees is the most common defect in a tree survey and a reliable way to attract a further information request.
What should I send with the instruction?
A topographical survey with levels, the draft site layout including the building footprint and driveway, existing and proposed drainage runs, any Tree Preservation Order reference or conservation area status, the council's pre-application response and the case officer's name. That package usually avoids a second site visit.
Sources and further reading
This article is general guidance about the planning system in England and, where stated, the rest of the UK. It is not legal or professional advice. Check your local planning authority’s validation requirements and take professional advice for your specific site.