Demystifying BS 5837: A Guide for Architects, Developers, and Homeowners
At Canopy IQ, we believe in Intelligent Tree Solutions. A key part of this is navigating the standards that protect trees during development. For anyone involved in design, demolition, or construction, from a homeowner planning an extension to a developer overseeing a large-scale project, understanding
BS 5837:2012 Trees in relation to design, demolition and construction – Recommendations is essential.
Trees are a valuable asset to any property or development, offering visual amenity, improving well-being, and even increasing property values. However, the construction process exerts significant pressure on them. A mature tree can be irreparably damaged in minutes by unwitting actions, with the effects sometimes not visible for several years.
This is where BS 5837:2012 provides a crucial framework. It is not a barrier to development; rather, it is a tool that assists in achieving a sustainable and harmonious relationship between trees and structures. This guide will walk you through the key stages of the process.
Why is BS 5837 Important?
Following the standard is not just good practice; it is a material consideration within the UK planning system. A professional tree survey and report conducted in line with BS 5837 demonstrates due diligence and can significantly smooth the planning application process, not least because local authorities are expected to seek an Arboricultural Impact Assessment as part of the minimum detail required for an application. Engaging with the standard early avoids costly delays, redesigns, and potential conflicts with the local planning authority. For homeowners, it ensures your valuable trees survive building works, preserving the character and value of your property.
The BS 5837 Process: A Step-by-Step Overview
The standard follows a logical sequence of events, ensuring trees are considered from the very beginning of a project.
Stage 1: The Tree Survey and Categorisation
The first step is always a detailed tree survey undertaken by a qualified arboriculturist. This should be completed
before specific design proposals are drawn up.
The survey records key information for each tree, including:
Species, height, and stem diameter.
Crown spread at the four cardinal points.
Physiological and structural condition.
Estimated remaining contribution in years.
Crucially, each tree is graded using the
cascade chart for tree quality assessment. This places trees into one of four categories:
Category A: Trees of high quality with at least 40 years of remaining life expectancy. These are significant constraints on development.
Category B: Trees of moderate quality with at least 20 years of remaining life expectancy.
Category C: Trees of low quality with at least 10 years of remaining life expectancy, or young trees with a stem diameter below 150 mm.
Category U: Trees that cannot realistically be retained for longer than 10 years due to their condition.
Stage 2: Identifying Constraints – The Root Protection Area (RPA)
This is one of the most critical concepts in the standard. The
Root Protection Area (RPA) is the minimum area around a tree deemed to contain sufficient roots and rooting volume to maintain the tree's viability.
Calculation: For a single stem tree, the RPA is calculated as an area equivalent to a circle with a radius 12 times the stem diameter.
The "No-Go" Zone: The RPA should be treated as the default construction exclusion zone. No construction activity, access, or storage of materials should occur within this area unless specific mitigation measures are agreed upon.
Stage 3: The Arboricultural Impact Assessment (AIA)
Once a design is proposed, the arboriculturist prepares an AIA. This evaluates the direct and indirect effects of the proposed layout on the trees identified for retention. The AIA will:
Identify which trees can be realistically retained and which need to be removed.
Assess the impact of any necessary tree pruning, such as for access.
Evaluate potential damage from demolition, access, storage, and changes in ground levels.
Stage 4: The Tree Protection Plan (TPP) and Arboricultural Method Statement (AMS)
Based on the AIA, two key documents are produced:
Tree Protection Plan (TPP): This is a scale drawing showing the finalized layout with the trees for retention and their RPAs clearly marked. Crucially, it shows the exact location of protective barriers and any necessary ground protection. The default specification is a well-braced scaffold framework with welded mesh panels.
Arboricultural Method Statement (AMS): If any construction activity is unavoidable within an RPA, an AMS is required. This document details the specific methodology for carrying out those works with minimal risk of damage to the tree. This could include specifications for special foundations, installation of services, or the use of temporary ground protection.
Partnering for Success
Successfully integrating trees into a development project is a collaborative process. At Canopy IQ, we leverage our 24 years of experience and the latest surveying technology to provide clear, easy-to-understand reports that satisfy planning authorities and guide your design team.
By engaging with the BS 5837 process early, you can unlock the full potential of your site, mitigate risks, and create a high-quality, sustainable development that benefits from the maturity and character that only established trees can provide.
If you are an architect, developer, planner, or homeowner embarking on a project, contact Canopy IQ today to discuss how our expert BS 5837 services can provide you with the intelligent tree solutions you need.
