BS 5837:2012 Explained: Tree Surveys, Categories and Protection

BS 5837:2012 is the British Standard behind every planning tree survey. Here is what it covers, what the categories mean, and what it requires on site.

Written by John McNamara, arboricultural consultant, McNamara Tree Consultancy

BS 5837:2012, often written BS5837 and in full "Trees in relation to design, demolition and construction — Recommendations", is the British Standard that governs how trees are surveyed, categorised and protected wherever development and trees meet. When a planning authority in Northern Ireland, the wider UK or Ireland asks for a tree survey with your application, BS 5837 is the document they expect it to follow.

The standard was published in 2012, replacing the 2005 edition, and remains current. Understanding its main moving parts makes every conversation with your architect, planning officer or arboricultural consultant considerably easier.

What a BS 5837 tree survey records

The survey is the foundation. Every relevant tree on or near the site is recorded with its species, height, stem diameter, crown spread, age class, physiological and structural condition, and estimated remaining contribution. From those observations each tree receives a quality category, and the survey data feeds the constraints plan the design team works from. You can read how we deliver this on our BS 5837 tree survey service page, and if surveys are new to you altogether, start with what an arboricultural survey is.

Tree categories: A, B, C and U

The famous part of the standard is its grading system, and it is simpler than it looks.

• Category A: trees of high quality with at least 40 years' contribution remaining. The site's best assets, which designs should work hard to keep.
• Category B: trees of moderate quality with 20 or more years remaining, the largest group on most sites.
• Category C: trees of low quality, or young trees of limited stature, with at least 10 years remaining.
• Category U: trees that cannot realistically be retained longer than 10 years in the context of the current land use, usually through serious defects or decline.

Categorisation is an expert judgement made tree by tree, which is why the standard requires the survey to be carried out by a competent arboriculturist rather than filled into a template.

Root protection areas and tree protection

For every retained tree the standard calculates a root protection area (RPA): a zone, based on stem diameter, where construction activity is presumed to damage the roots that keep the tree alive and stable. The Tree Protection Plan draws those zones on the site layout, and protective fencing turns them into construction exclusion zones on the ground. Where work must intrude, an Arboricultural Method Statement sets out precisely how it will be done without unacceptable harm.

This is the part planning conditions bite on: authorities routinely require the fencing to be installed, inspected and retained for the duration of the build.

Is there a BS 5837 template or free PDF?

Two questions people search constantly. The standard itself is a licensed publication sold by BSI, so there is no legitimate free PDF, and beware of sites offering one. As for templates: the survey schedule format is broadly standard, but the content is fieldwork and judgement — a template cannot categorise a tree, calculate an RPA around real constraints, or defend the conclusions to a planning officer. What you actually need is a competent survey, typically turned around quickly and priced by site.

When you need one

If your planning application involves land with trees on it or beside it, in practice you need a BS 5837 tree survey; our guide to when a tree survey is required covers the common situations. We carry out BS 5837 tree surveys across Northern Ireland and Ireland, with UK-standard reports accepted by every local authority. Request a quote with the site address and proposal, and you will have a clear price and timescale the same week.