What Type of Tree Survey Do I Need?
The term “tree survey” can describe several different arboricultural services. A survey for a planning application will have a different purpose, scope and output from one prepared for a property purchase or to assess the safety of existing trees.
The right survey usually depends on one simple question:
What has prompted you to seek professional advice about the trees?
This guide explains the most common types of tree survey, what each is intended to achieve and which one may be appropriate for your situation.
A quick guide to choosing a tree survey
You may require:
a BS5837 tree survey if you are planning an extension, new building, redevelopment or other construction work near trees.
a mortgage tree report or property risk tree survey if you are buying a property, responding to a request from a lender, insurer or building surveyor, or otherwise concerned about trees in proximity to buildings.
a tree condition or risk assessment if you are concerned about the condition or safety of trees, or are responsible for managing trees on a property or site\
a tree survey for foundation design if an engineer, architect, warranty provider or building control body needs specific tree information to help determine foundation requirements.
These surveys are not interchangeable. Selecting the survey according to its purpose helps ensure that the report contains the information needed by the person or organisation requesting it.
BS5837 tree surveys for planning and development
A BS5837 tree survey is usually the appropriate starting point where demolition, design or construction work is proposed near trees.
BS5837:2012 is the current British Standard for trees in relation to design, demolition and construction. It applies whether or not planning permission is required and is intended to help integrate trees and development in a sustainable way.
A BS5837 survey may be needed for projects such as:
home extensions;
new houses or other buildings;
redevelopment of an existing site;
new access routes or driveways;
demolition close to trees;
changes to ground levels;
new hard surfaces, drainage or services near trees.
The initial survey records relevant trees on and near the site and assesses their quality. It will be accompanied by a tree schedule and Tree Constraints Plan showing information such as tree positions, canopy spreads, retention categories and Root Protection Areas.
The standard recommends obtaining the tree survey early so its findings can inform feasibility work and design options, rather than waiting until a layout has already been fixed.
Depending on the project and its stage, further information may then be required, including:
an Arboricultural Impact Assessment;
an impact assessment plan;
an Arboricultural Method Statement;
a Tree Protection Plan;
construction-stage arboricultural supervision or monitoring.
A BS5837 survey does record relevant observations about tree condition, but its primary purpose is to inform design, planning and construction. It should not automatically be treated as a dedicated tree safety assessment for every tree on or near the site.
Mortgage tree reports and pre-purchase tree surveys
A mortgage tree report and a pre-purchase tree survey are different names commonly used for the same general type of service.
This survey is intended for people buying a property, their agents, and situations where a lender, insurer, solicitor or building surveyor has requested further information about nearby trees. It can also be used where there are concerns about trees in proximity to buildings, whether the property is being purchased or is already owned.
It may be appropriate where:
mature trees are close to the house;
a building survey has raised concerns about trees;
a lender or insurer has requested an arboricultural report;
there are questions about subsidence or heave risk;
the buyer wants to understand likely future tree management.
The assessment considers the trees in relation to the property. Depending on the circumstances, this may include tree species, size, condition and proximity to buildings, visible signs of direct damage, relevant soil information, potential subsidence and heave factors, and likely management requirements.
Trees close to a property are not automatically a significant problem. The purpose of the report is to provide proportionate advice based on the trees, site conditions and available information rather than treating proximity alone as evidence of likely damage.
A pre-purchase tree report is an arboricultural assessment. It does not replace a structural survey, drainage investigation or geotechnical assessment, although it should be considered alongside them where appropriate.
Tree condition surveys and tree risk assessments
A tree condition survey may be appropriate when the main concern is the current condition of one or more trees.
This could include:
a homeowner concerned about a particular tree;
visible defects or storm damage;
trees close to targets (buildings, roads, paths, play areas etc.);
a school, estate or business responsible for managing trees;
a property manager establishing a suitable inspection programme;
uncertainty about whether pruning, monitoring or further investigation is required.
A tree condition assessment generally considers the visible structural and physiological condition of the tree from ground level. It can identify relevant risk features, obvious health concerns and management recommendations.
A tree risk assessment places greater emphasis on the likelihood and consequences of tree or branch failure in relation to how the surrounding area is used. A tree beside a busy road, school entrance or frequently used path may therefore need to be considered differently from an equivalent tree in an area with very limited access.
National Tree Safety Group guidance states that tree owners have a legal duty of care, while also emphasising that tree risk management should be balanced, reasonable and proportionate. The overall risk from trees is very low, and responsible management does not mean seeking to eliminate every possible risk or removing trees unnecessarily.
For an individual tree or small residential site, a focused tree condition survey may be sufficient. For a larger site or managed tree population, a structured risk assessment and prioritised management recommendations may be more appropriate.
Tree surveys for foundation design
A tree survey for foundation design has a narrower and more technical purpose than a BS5837 planning survey.
It may be requested where a new house, extension or other structure is proposed near trees and a structural engineer, architect, warranty provider or building control body needs tree information to help assess foundation requirements.
The survey will usually provide relevant information such as:
tree species;
current tree height;
expected mature height;
water-demand classification;
tree positions on a scaled plan.
This information can then be used by the appointed designer or engineer when considering foundation requirements, particularly where shrinkable soils and tree influence need to be taken into account.
The arboricultural consultant supplies the relevant tree and vegetation information. The final foundation depth, engineering design and compliance with building-control or warranty requirements remain the responsibility of the appropriate designer or engineer.
A development may require both a BS5837 survey and a foundation-design tree survey. The first helps address planning, layout and tree protection, while the second supplies specific information for foundation calculations.
Can one project require more than one type of tree survey?
Yes. The correct services depend on the different questions that need to be answered.
For example:
a homeowner planning an extension may require a BS5837 survey for planning and separate tree information for foundation design;
a homebuyer may require a pre-purchase tree survey, and also a BS5837 survey for a planned extension.
an estate may require a general tree risk-management survey as well as BS5837 reports for a proposed development area;
The fact that a tree has already been inspected does not necessarily mean the existing report is suitable for a different purpose.
What information should I provide when requesting a tree survey?
You do not need to identify the correct technical name before making an enquiry.
As a starting point, provide:
the site or property address;
a brief explanation of what has prompted the enquiry;
the wording of any request received from a planning authority, lender, insurer, building surveyor, engineer or other professional;
available site plans or proposed drawings;
photographs where these help explain the concern;
any relevant deadlines or project stage.
The wording of the request is often more useful than trying to interpret it yourself. An arboricultural consultant can then confirm the likely service and the information needed to provide a quotation.
Choosing the right tree survey
The most important distinction is not the name of the survey, but the reason it is required.
As a general guide:
Planning or building near trees: BS5837 tree survey.
Buying a property or responding to a lender: mortgage tree report or pre-purchase tree survey.
Concern about tree condition or safety: tree condition or risk assessment.
Foundation calculations near trees: tree survey for foundation design.
Where the circumstances overlap, more than one report may be appropriate.
Professional arboricultural advice
Flow Tree Consultancy provides independent tree surveys, written reports and arboricultural advice across Kent, Sussex, London, Surrey and Hampshire.
The consultancy is led by a qualified arboricultural consultant with a First Class BSc (Hons) in Arboriculture and Urban Forestry, Professional Membership of the Arboricultural Association, LANTRA Professional Tree Inspector training and approximately ten years of industry experience.