What You Need to Know
If you are planning a new development, extension or other works where trees could be affected, a tree survey report is likely to form an important part of the planning process.
For many applicants, this can come as a surprise and feel like an unwelcome addition to an already complex process. This guide explains what is required, why planning authorities ask for arboricultural information, and how approaching tree matters in the right way from the outset can save significant time, cost and stress.
Why Do Planners Require a Tree Survey?
Trees are a material consideration in the planning process. Local planning authorities need to understand the trees that could be affected by a proposed development and whether they make a positive contribution to the site or wider environment.
A tree survey is not a box-ticking exercise. It is a decision-making tool – one that helps the applicant, architect, designer, engineer and planning officer understand which trees can be removed, which should be retained, and how development can be successfully designed around those that remain.
A well-prepared tree survey demonstrates that arboricultural issues have been addressed at the design stage, rather than left as an afterthought, and gives the planning authority confidence that the relationship between trees and the proposed development has been properly considered.
A survey will typically be required where trees could be affected by demolition, construction, new foundations, drainage, access works, changes in ground level or other development activity. It is therefore important to look beyond the footprint of the building being proposed and consider the wider impact of the scheme.
Providing a quality tree survey alongside a planning application can also reduce the risk of delays during validation or subsequent assessment. A quality tree survey addresses arboricultural issues up front and helps demonstrate that the potential effects of development on trees have been properly considered.
What is a BS5837 Tree Survey?
The industry standard is BS5837:2012 ‘Trees in Relation to Design, Demolition and Construction’. This British Standard sets out a structured methodology that gives Designers, Architects, Engineers and Planners the information they need to make informed decisions and reduce ambiguity around trees and your build.
A complete BS5837 submission typically includes:
- A tree schedule recording species, dimensions, age class, condition and remaining contribution of each tree
- A Tree Constraints Plan showing canopy spreads, Root Protection Areas (RPAs), and tree category – assessed on the basis of quality, condition and longevity
How Trees Are Categorised in BS5837
Each tree is assessed and placed into one of four categories:
- Category A – High quality tree with significant longevity (40+ years). Given greatest weight by planners.
- Category B – Moderate quality tree with at least 20 years remaining. Retention desirable where feasible.
- Category C – Low quality trees of limited value with at least 10 years remaining. Includes young trees. Trees unlikely to represent a constraint on planning.
- Category U – Unsuitable for retention due to structural defects, disease or decline. Managed life expectancy less than 10 years.
The category assigned to a tree is not, on its own, a decision to retain or remove it. The categories provide an assessment of the tree’s quality, condition and likely longevity, which can then be considered alongside the proposed development.
Root Protection Areas — Why Do They Matter to Your Design?
The Root Protection Area (RPA) is a defined zone around each tree within which ground disturbance should be avoided. RPAs are often shown as a circle centred on the base of the tree, but the shape may need to be adjusted where existing site features or other conditions influence the likely distribution of roots.
Showing RPAs accurately on a Tree Constraints Plan allows the design team to identify potential conflicts early – before they become costly redesign problems. Foundations, drainage, services, level changes, access routes and hard surfacing all need to be considered in relation to each tree’s RPA.
Importantly, the RPA is a design constraint rather than simply a line on a drawing. Understanding the extent and significance of the constraint is what allows the design team to make informed decisions about how development can be accommodated.
The Importance of Accurate Tree Mapping
Design teams need trees to be plotted accurately so that drawings can be properly overlaid and coordinated. In many cases, adjusting a layout by just a few metres can make the difference between a scheme that impacts a significant tree and one that avoids it entirely – but only if the survey data and mapping are reliable enough to work from.
Inaccurate tree mapping can introduce uncertainty and lead to unnecessary design changes. Using aerial photography as a base plan, or GPS equipment without sufficient accuracy, can introduce errors that undermine the value of the survey.
On larger schemes, it is usual for tree positions to be plotted as part of a topographical survey. Where this information is not available, trees should be accurately plotted by the arboriculturist using appropriate survey equipment, with plans prepared in CAD so that architects and engineers can overlay the information directly onto working drawings with confidence.
Common Reasons Applications Are Not Validated
A poorly prepared or incomplete tree survey can lead to queries, delays and additional work during the planning process. Here are some of the most common reasons a planning application stalls.
- Inconsistent tree numbering between tree schedule and tree plans
- Plans missing or not matching the proposed layout
- RPAs missing or shown incorrectly
- Tree Survey scope too narrow
Protected Trees – What You Need to Be Aware Of
Some trees carry a higher level of legal protection that must be considered before any works or development proceeds. The two most common forms are Tree Preservation Orders (TPOs) and Conservation Area protections.
A TPO is a formal designation by the local authority making it a criminal offence to cut down, uproot, top, lop or carry out any works to a protected tree without prior written consent. Within Conservation Areas, all trees with a trunk diameter over 75mm at 1.5 metres above ground are automatically protected, and six weeks’ notice must be given to the local authority before any works take place.
Your BS5837 survey will identify any protected trees on or near your site and set out the implications for your scheme. Understanding this early, before your design is finalised, will avoid significant complications further down the line.
Why Early Arboricultural Input Makes a Difference
The most effective approach is to commission your tree survey before your Architect starts the design in earnest. When arboricultural constraints are understood from the outset, the design can respond to them rather than conflict with them.
Trees identified late in the process frequently result in redesigned foundations, revised drainage layouts, repositioned access points, or planning objections which could have been avoided entirely. These changes are expensive and time-consuming. A tree survey commissioned early is an investment in a smoother, faster planning process – and often pays for itself many times over in avoided redesign costs.
We work closely with Architects, Designers and Engineers throughout the process to ensure the arboricultural work is fully coordinated with the design. Our reports are written with planning in mind – structured to meet LPA expectations, address the questions Planners ask, demonstrate your environmental compliance and minimise the risk of queries or delays.
A note on the Arboricultural Impact Assessment
The BS5837 survey is the foundation, but it is only part of the picture. Where development proposals could affect trees, the survey is extended into an Arboricultural Impact Assessment (AIA). This is the stage at which an experienced consultant assesses how the design layout interacts with trees and works with the architect to develop a practical mitigation approach.
This is where the quality of your Arboriculturist really matters. A planning-focused consultant brings technical knowledge of construction methods, foundation design and mitigation techniques, and can have a meaningful design conversation rather than simply flagging constraints. The result is a Tree Protection Plan and Arboricultural Method Statement that is workable on site and right first time – not one that generates queries or requires revision at planning.
For this reason, it is strongly recommended to appoint a qualified, planning-focused Arboriculturist at the BS5837 survey stage, so that the right expertise is in place when it counts. The AIA and method statement are covered in detail in Part 2 of this article.
Let’s Get Your Application Moving
Trees don’t have to slow your project down. With the right survey in place from the start, they become a manageable part of the process – not an obstacle.
We bring planning-focused expertise, sub-metre GPS accuracy and CAD-quality plans to every commission, and we have the technical know-how to work constructively with your architect or designer to keep plans on track and serving your interest.
Get in touch today – tell us about your project and we’ll let you know exactly what you need.