If you are planning an extension, a new home, a commercial development, or any form of construction near trees, you may be told that a BS5837 tree survey is required. For many homeowners and developers, receiving the survey can feel overwhelming. The plans are often covered in coloured circles, technical measurements, and unfamiliar terminology.
The good news is that a BS5837 survey is not designed to make your project more complicated. Its purpose is to help ensure that valuable trees are considered properly during the design and construction process, reducing planning issues and helping developments coexist with the surrounding landscape.
This guide explains the key parts of a BS5837 tree survey in plain English, helping you understand what the information means and how it can be used to shape a successful project.
What Is a BS5837 Tree Survey?
BS5837 refers to BS5837:2012 Trees in Relation to Design, Demolition and Construction – Recommendations, the British Standard used throughout the planning and development process when trees may be affected by proposed works.
The purpose of a BS5837 tree survey is to:
- Identify the trees present on a site.
- Assess their condition and value.
- Evaluate their likely contribution to the landscape.
- Highlight constraints that trees may place on development.
- Inform the design process before planning applications are submitted.
Local Planning Authorities rely heavily on BS5837 surveys when determining planning applications involving trees. The survey helps planners understand which trees are important, which could potentially be removed, and how retained trees can be protected throughout construction.
Rather than viewing the survey as a planning obstacle, it should be seen as a valuable design tool that can help avoid costly redesigns later in the process.
Understanding Tree Categories: A, B, C and U
One of the first things most people notice in a BS5837 survey is that every tree is assigned a category. These categories indicate the tree’s quality and likely future contribution.
Category A Trees
Category A trees are considered to be of the highest quality.
They are typically:
- Healthy and structurally sound.
- Visually prominent within the landscape.
- Capable of making a significant contribution for at least 40 years.
Examples may include mature oak trees, veteran trees, or prominent specimen trees that form an important part of the local character.
These trees usually carry significant planning weight and should be retained wherever possible.
Category B Trees
Category B trees are good-quality trees that offer meaningful value but fall short of Category A status.
This may be because they are:
- Slightly younger.
- Less visually prominent.
- Beginning to show minor defects.
- Growing within groups where their individual contribution is reduced.
Category B trees are still considered worthy of retention and often play an important role in planning decisions.
Category C Trees
Category C trees have lower overall value but may still provide benefits.
They may have:
- Limited landscape importance.
- Reduced life expectancy.
- Minor structural or physiological issues.
- Less visual prominence.
Importantly, Category C does not mean a tree should automatically be removed. Many Category C trees provide screening, habitat value, privacy, or contribute positively to the appearance of a site.
Category U Trees
Category U trees are trees that are unsuitable for long-term retention.
These are typically trees with:
- Significant structural defects.
- Advanced decline.
- Serious disease.
- Very limited remaining life expectancy.
Category U trees are generally recommended for removal, often on safety or management grounds.
Understanding Root Protection Areas (RPAs)
One of the most important elements of any BS5837 survey is the Root Protection Area (RPA).
The RPA represents the minimum area around a tree that should remain largely undisturbed to protect the roots and supporting soil environment.
On plans, the RPA is usually shown as:
- A coloured circle around the tree.
- Occasionally a modified polygon where site conditions require adjustment.
Think of the RPA as an invisible protection zone beneath the ground.
It helps determine:
- Where buildings can be positioned.
- Where driveways and hard surfaces can be installed.
- Where services such as drainage and utilities can run.
- Where construction traffic and material storage should be avoided.
Damage within the RPA can significantly affect a tree’s long-term health and stability.
Can You Build Within a Root Protection Area?
A common misconception is that development can never take place within an RPA.
In reality, some incursions may be possible if carefully designed and properly justified.
Examples include:
- Piled foundations instead of traditional strip foundations.
- No-dig driveway construction.
- Specialised surfacing systems.
- Sensitive routing of underground services.
However, any encroachment into an RPA must be assessed carefully by arboricultural and engineering professionals.
The greater the incursion, the greater the risk to the tree and the more difficult it may be to secure planning approval.
Understanding Tree Constraints Plans
The Tree Constraints Plan is often the most important drawing within a BS5837 report.
It combines information about:
- Tree locations.
- Crown spreads.
- Root Protection Areas.
- Future growth requirements.
This allows architects and designers to understand where trees may influence the layout of a development.
A good Tree Constraints Plan helps identify potential conflicts early, before detailed design work is undertaken.
Shading Arcs and Future Growth
Many BS5837 reports include shading diagrams showing where tree canopies may cast shade throughout the day.
These are particularly important for:
- New residential developments.
- Garden design.
- Outdoor amenity spaces.
- Solar gain considerations.
A tree that seems relatively small today may become significantly larger over the lifespan of a development.
Considering future growth helps avoid situations where new occupants later complain about:
- Excessive shade.
- Leaf fall.
- Branch overhang.
- Perceived loss of light.
Designing with future growth in mind creates more sustainable and successful developments.
Using a BS5837 Survey as a Design Tool
The most successful projects use the BS5837 survey at the beginning of the design process rather than after plans have already been drawn.
When reviewing a survey, consider:
Which Trees Add the Most Value?
Look first at Category A and B trees.
Can these become features within the development?
Retaining mature trees often adds character, desirability, biodiversity, and landscape value that can take decades to recreate.
Which Trees Could Be Removed?
Some Category C or U trees may constrain development while offering relatively limited value.
In some cases, their removal may improve both the design and long-term landscape quality of a site.
Are There Obvious Future Conflicts?
Review:
- Root Protection Areas.
- Shading patterns.
- Future crown growth.
If buildings are being forced into constrained areas, redesigning early is often easier and cheaper than addressing objections later.
How a BS5837 Survey Helps Planning Applications
Planning officers use BS5837 information to assess whether a development has properly considered existing trees.
A well-prepared survey can help demonstrate:
- Responsible site design.
- Protection of important landscape features.
- Appropriate tree retention.
- Justified tree removals.
- Sustainable development principles.
Conversely, schemes that ignore tree constraints often face delays, redesign requests, or planning refusal.
When Should You Seek Professional Advice?
You do not need to become an arboricultural expert to understand a BS5837 report, but professional guidance can be invaluable when:
- Designing layouts around important trees.
- Planning foundations within or near RPAs.
- Installing driveways or services near retained trees.
- Assessing whether tree removals are likely to be supported.
- Responding to planning authority comments.
A qualified arboricultural consultant can work alongside architects, engineers, and planners to help achieve a balanced outcome that protects valuable trees while allowing development to proceed.
Final Thoughts
A BS5837 tree survey is much more than a planning requirement. When used properly, it becomes a powerful design tool that helps shape better developments, protect valuable trees, and reduce planning risk.
By understanding tree categories, Root Protection Areas, shading implications, and future growth requirements, homeowners and developers can make more informed decisions from the outset.
The result is often a development that works better for people, respects existing trees, satisfies planning requirements, and creates a more attractive environment for years to come.
At Devon Tree Services, we provide BS5837 surveys, arboricultural reports, and practical advice for homeowners, developers, architects, and planning professionals across Devon. If you’re planning a project involving trees, our team can help you understand the constraints, opportunities, and solutions available.
