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By the Blue Harbour Estates arboriculture team. Last updated 18 August 2026. TL;DR: A tree survey is a written inspection of the trees on a site, carried out by a qualified arboriculturist, that records each tree's species, size, condition and risk, then sets out what work is needed and when to look again. Commercial sites …
By the Blue Harbour Estates arboriculture team. Last updated 18 August 2026.
TL;DR: A tree survey is a written inspection of the trees on a site, carried out by a qualified arboriculturist, that records each tree’s species, size, condition and risk, then sets out what work is needed and when to look again. Commercial sites generally need one of two types: a tree safety survey (also called a tree risk assessment), which supports your legal duty of care to staff and the public, or a BS5837 survey, which is required when you are applying for planning permission on a site with trees. In the UK you should expect to pay roughly £300 to £800 for a small site safety survey, £400 to £1,500 for a standard BS5837 planning package, and several thousand for large or complex estates, with arboricultural consultant rates typically £75 to £120 per hour. Most commercial sites with public access are re-inspected every 12 to 36 months depending on risk. Need yours sorted? Book a free site visit and quote.
A tree survey is a formal, recorded inspection of the trees on a piece of land, carried out by a competent arboriculturist and written up into a report you can act on and rely on.
At minimum a survey records, for every tree assessed: a unique reference number, species, height, trunk diameter, crown spread, estimated age class, physiological and structural condition, any defects or hazards, and a recommendation with a priority timescale. Most surveys are supported by a tree schedule (the table of data), a plan showing each numbered tree, and photographs of anything significant.
The point is not the paperwork. The point is that you end up with a defensible, evidence based picture of what you own, what it might do, and what you are going to do about it. That is what an insurer, a health and safety inspector, a planning officer or a court will want to see.
Tree surveys sit within our wider arboriculture service, alongside tree tagging, tree mapping, remedial works and emergency call outs, so the same team that inspects your trees can also carry out the work the report recommends.
Because if you own or occupy land, the trees on it are your legal responsibility.
Under the Occupiers’ Liability Acts 1957 and 1984, anyone who owns, rents or occupies land owes a duty of care to take reasonable steps to ensure people on that land are reasonably safe. If your site has employees or members of the public on it, the Health and Safety at Work etc. Act 1974 also applies, and requires risk to be managed so far as is reasonably practicable.
The legal test that matters is reasonable foreseeability. You are not expected to guarantee that no branch will ever fall. You are expected to have a sensible system for spotting foreseeable problems and acting on them. A landowner who has never looked at their trees and cannot show any record of inspection is in a very weak position when something fails. A landowner with a dated survey, a documented risk assessment and evidence that recommended works were carried out is in a strong one.
The HSE and the National Tree Safety Group both take a proportionate view. Their guidance is clear that doing what is reasonably practicable does not mean every tree needs an individual detailed examination on a fixed cycle. It means the effort you put in should reflect the actual risk, which is driven mostly by how many people are near the trees and how often.
That is good news for commercial sites, because it means a sensible zoned approach is both cheaper and more defensible than either ignoring the problem or over surveying everything.
Beyond liability, there are three other reasons commercial clients commission surveys:
The word “survey” covers several quite different products, and buying the wrong one is the most common and most expensive mistake we see. Here is how they compare.
| Survey type | What it is for | When you need it | Typical UK cost | Typical output |
|---|---|---|---|---|
| Tree safety survey / tree risk assessment | Identifying trees that pose a foreseeable risk to people or property | Ongoing duty of care on any occupied site with trees | £300 to £800 for a small site, priced per site or per day on estates | Tree schedule, risk ratings, prioritised works list, re-inspection date |
| BS5837 tree survey | Informing design and protecting trees during development | Any planning application on a site with trees on or next to it | £400 to £1,500 for a standard package, more on complex sites | Tree schedule, tree constraints plan, arboricultural impact assessment, tree protection plan, method statement |
| Mortgage or subsidence survey | Assessing whether trees are influencing a building’s foundations | Property purchase, cracking, insurance claim | £300 to £700 | Report on tree to building relationships and recommendations |
| Detailed or decay investigation | Diagnosing a specific suspect tree | When a visual inspection cannot resolve a concern | £300 to £1,000 plus per tree | Decay detection results and a retain, treat or remove recommendation |
| Tree stock survey and mapping | Building an asset inventory for a portfolio or estate | Managing a large or multi site estate over time | Priced per tree or per day | GIS or spreadsheet tree inventory, often with tagging |
For most commercial property managers, the workhorse is the tree safety survey, refreshed on a cycle, with a BS5837 survey commissioned only when development is on the cards.
A BS5837 tree survey is the arboricultural assessment required to support a planning application, carried out to British Standard BS 5837:2012 “Trees in relation to design, demolition and construction”.
It categorises every relevant tree into category A (high quality, worth retaining), B (moderate quality), C (low quality) or U (unsuitable for retention, generally because it is dead or dangerous). It then calculates each retained tree’s root protection area and produces a tree constraints plan showing where you can and cannot realistically build.
If your proposals affect trees, you will usually also need an arboricultural impact assessment, a tree protection plan and an arboricultural method statement. Many planning authorities will refuse to validate an application without them, which means a missing survey can stall a project for weeks.
The practical tip: commission the BS5837 survey before the architect finalises the layout, not after. A survey done early shapes the design and usually saves trees and money. A survey done late tends to produce a report explaining why the scheme does not work.
Costs vary with the number of trees, the site’s complexity and the documents required, but current UK market rates give a reliable guide.
Three things drive the number more than anything else. First, tree count, though the cost per tree falls as the number rises. Second, the deliverables your planning authority or insurer expects, since plans and method statements take drawing time as well as site time. Third, access and complexity, because dense boundary vegetation, steep ground and trees that need close inspection all take longer.
One cost worth flagging: on a portfolio, a single co-ordinated survey across multiple sites is materially cheaper per site than commissioning them one at a time. If you manage several properties in Kent or the South East, bundle them.
If you are budgeting the wider site as well, our guide to commercial grounds maintenance costs sets out how tree work usually sits alongside mowing, hedges and winter services in an annual contract.
There is no single legally prescribed interval, and anyone who tells you there is has oversimplified it. Frequency should reflect the risk, which in practice means how many people are exposed and how often.
A workable zoned approach for a commercial site looks like this:
Two other triggers are easy to forget. Any change of use that puts more people under the trees resets the risk picture, and so does any construction work near the roots. Both should prompt a fresh look.
Kent’s climate makes a couple of these more pressing than they would be further north. Hot, dry summers followed by wet, windy winters put stress on mature trees, and the county’s ash population continues to be affected by ash dieback, which can turn a stable tree into a brittle one over a small number of seasons. Ash near a car park or public footpath is the single most common thing we flag on Kent commercial sites.
The person inspecting your trees should be a competent arboriculturist, which in practice means relevant qualifications, demonstrable experience and insurance.
Look for a Level 4 arboricultural qualification or above for reporting work, membership of a recognised professional body such as the Arboricultural Association or the Institute of Chartered Foresters, familiarity with a recognised risk assessment methodology, and professional indemnity insurance alongside public liability. For BS5837 work, ask specifically whether they have produced reports accepted by your local planning authority.
Ask to see a sample report before you commit. A good one is clear, dated, plan referenced and gives you unambiguous actions with priorities. A poor one is a page of caveats.
At Blue Harbour Estates we are SafeContractor and SSIP accredited, ISO 45001 certified and Achilles registered, and we check for Tree Preservation Orders and conservation area status before any works begin.
Often, yes. Trees protected by a Tree Preservation Order, or standing in a conservation area, need consent from the local planning authority before most works, and carrying out unauthorised work on a protected tree is a criminal offence that can attract a substantial fine.
For a TPO tree you apply to the council for consent, which normally takes around eight weeks. In a conservation area you give six weeks’ notice of your intention to work on a tree with a trunk diameter over 75mm. There is an exemption for genuinely dead, dying or dangerous trees where work is urgently necessary, but you should document the justification with photographs and, ideally, notify the council anyway.
If you have hedges as well as trees, timing matters just as much, and it is worth reading our guide to the nesting season rules for commercial hedge cutting before booking any autumn or spring work.
A survey that sits in a drawer offers very little protection. The value is in what you do next.
The most common failure we see is not an absent survey. It is a survey from four years ago with a works list that was never actioned. That is arguably worse than no survey at all, because it documents that you knew.
If you manage a commercial site, a school, a retail park, a housing estate or an industrial unit anywhere in Kent, London or the South East, tree safety is one of the few risks on your site that is both entirely foreseeable and relatively cheap to manage properly.
Blue Harbour Estates carries out tree risk assessments, tree tagging and mapping, and the full range of remedial and emergency tree works across the region, and we can build inspection cycles into a wider grounds maintenance contract so nothing gets missed.
Request a free, no obligation site visit and quote and we will walk your site, tell you honestly what level of survey you actually need, and price it clearly.
What is a tree survey? A tree survey is a written inspection of the trees on a site by a qualified arboriculturist, recording each tree’s species, size, condition, defects and risk, together with recommended works and a re-inspection date.
Is a tree survey a legal requirement in the UK? There is no law that says “you must have a tree survey”. However, the Occupiers’ Liability Acts 1957 and 1984 and the Health and Safety at Work etc. Act 1974 impose a duty of care, and a documented survey is the standard way of demonstrating you have taken reasonable steps. For planning applications on sites with trees, a BS5837 survey is effectively mandatory because councils will not validate without one.
How much does a tree survey cost? Expect roughly £300 to £800 for a small commercial site safety survey and £400 to £1,500 for a standard BS5837 planning package, with larger estates running into several thousand. Consultant rates are typically £75 to £120 per hour or £450 to £800 per day.
How long does a tree survey last? Most reports carry a stated validity, commonly 12 to 24 months for safety surveys on sites with public access. BS5837 reports are usually accepted for around 12 months by planning authorities, though this varies and a long delayed application may need updating.
How often should trees be inspected on a commercial site? Every 12 to 24 months in high traffic areas such as car parks and entrances, every 24 to 36 months in lower access areas, plus an additional inspection after storms, drought summers or nearby construction.
What is the difference between a tree survey and a tree risk assessment? A tree risk assessment is a type of tree survey focused specifically on whether trees pose a foreseeable danger to people or property. A tree survey is the broader term and can also cover planning, asset inventory or subsidence purposes.
Can I do a tree survey myself? An informal walkover by trained site staff is genuinely useful between formal inspections and is encouraged by NTSG guidance. But for a report you intend to rely on legally or submit for planning, you need a competent, qualified and insured arboriculturist.
Do I need permission to remove a tree after a survey? If the tree has a Tree Preservation Order or stands in a conservation area, yes. TPO consent takes around eight weeks and conservation area work requires six weeks’ notice. Genuinely dead or dangerous trees are exempt, but document your justification.
