Arboricultural Impact Assessment (AIA)
Planning-ready BS 5837 assessments that identify how your development interacts with trees — clear constraints, practical mitigation and predictable outcomes.
Designs evolve, layouts shift and tree constraints become clearer with every stage. An AIA gives planners and design teams the exact evidence they need to progress without unnecessary redesigns or delays.
Design meets trees — and certainty keeps projects moving
Conflicts with root protection areas, shading, overhang or retention categories can stall progress at the wrong moment.
A focused AIA shows how your layout interacts with every relevant tree and sets out reasonable, proportionate solutions.
What is an Arboricultural Impact Assessment (AIA)?
An AIA evaluates how a proposed development affects trees on and around the site.
Under BS 5837, it assesses:
- root protection areas (RPAs)
- above-ground constraints (crown spread, shading, future pressure)
- retention categories
- construction impact and design conflicts
- access, storage and working areas
- tree retention feasibility
- required mitigation
The result is a clear, planning-ready assessment showing how tree constraints have been considered and managed.
The AIA Process
| Step | Description |
|---|---|
| 1. Initial Review | Share the layout, site plan and any existing survey data. |
| 2. Site Survey | Assessment of tree condition, RPAs, crown spread and constraints. |
| 3. Impact Assessment | Evaluation of design conflicts and retention feasibility. |
| 4. Mitigation Strategy | Foundation advice, protection measures and design adjustments (if needed). |
| 5. Reporting | A clear, BS 5837-compliant report ready for submission. |
We keep guidance clear and planning-ready — supporting predictable project delivery.
Our Approach
Practical Mitigation
Foundation options, construction routes and protection measures built around real site conditions.
Design Aligned
Clear explanations of how tree constraints interact with the proposal.
Planning Led
Reports structured for direct LPA interpretation
Technical Clarity
Evidence presented cleanly, without ambiguity.
Do I Need an AIA?
You may need an AIA if:
- your layout falls within any RPA
- access routes pass near trees
- designs include new hard surfaces, levels changes or foundations close to trees
- shading or overhang affects proposed rooms or gardens
- you’re planning new utilities, drainage or service runs
- planners request BS 5837 evidence
- your architect highlights tree constraints
- your PEA has already flagged arboricultural considerations
An AIA clarifies design impacts and prevents late-stage planning queries.
Why this Matters for Planning
Tree constraints are a formal material consideration under the Town & Country Planning Act 1990 and BS 5837.
LPAs expect:
- clear mapping of constraints
- justification for removals
- practical mitigation where conflicts occur
- predictable construction methodology
- retention aligned with site use and long-term pressure
Weak evidence leads to validation delays, redesign requests or planning conditions tied to tree protection.
Case Note
Your Next Step
Need an Arboricultural Impact Assessment? We’ll confirm what’s required and align survey windows with your programme.
Phone: 0800 494 7479
Email: [email protected]
Areas We Cover
We cover many areas across England and Wales. Click below to find out more.
AIA Survey FAQs
What is an Arboricultural Impact Assessment AIA?
An Arboricultural Impact Assessment AIA is a planning document that evaluates how a proposed development may affect trees on or near a site. It identifies potential impacts on tree health, structure, and root protection areas, and sets out measures to avoid or mitigate harm in line with planning policy and British Standards.
When is an Arboricultural Impact Assessment required?
An AIA is typically required when trees are present on or adjacent to a development site and may be affected by construction. Local Planning Authorities often request an AIA to support planning applications where tree constraints are identified.
What does an Arboricultural Impact Assessment include?
A compliant AIA usually includes:
• Tree survey data in accordance with BS5837
• Tree categorisation and constraints plan
• Assessment of development impacts
• Root Protection Area analysis
• Arboricultural Method Statement where required
• Tree Protection Plan for construction
This ensures the report is suitable for planning submission and validation.
What is the difference between a tree survey and an AIA?
A tree survey records and categorises trees on site, while an Arboricultural Impact Assessment builds on that data to assess how a proposed development will affect those trees. The AIA is a planning document, not just a survey.
What is the British Standard for Arboricultural Impact Assessments?
AIAs are carried out in accordance with BS5837:2012 Trees in relation to design, demolition and construction. This standard provides guidance on how trees should be surveyed, assessed, and protected during development.
How does an AIA support planning permission?
An AIA demonstrates to the Local Planning Authority that tree constraints have been properly considered and addressed. It helps ensure development proposals are sustainable, policy compliant, and less likely to be delayed or refused due to arboricultural concerns.
Can an AIA help avoid tree removal?
Yes. A well prepared AIA can influence site layout and design to retain high value trees where possible. It identifies constraints early, allowing adjustments that reduce the need for unnecessary tree removal.
What happens if an AIA is not provided?
If an AIA is required but not submitted, the planning application may be invalidated or refused. Incomplete arboricultural information is a common reason for delays in planning decisions.
How long does an Arboricultural Impact Assessment take?
Timeframes depend on site size and complexity. For most residential developments, site surveys and reporting can typically be completed within a few days to a couple of weeks. Larger or more complex sites may require longer.
How much does an Arboricultural Impact Assessment cost?
Costs vary depending on site size, tree numbers, and development complexity. AIA reports are planning ready technical documents and include survey work, analysis, and report preparation. Fees are confirmed following a review of the site and project requirements.
Do I need an AIA for small developments?
Even small developments may require an AIA if trees are present and could be affected. Requirements are set by the Local Planning Authority, so it is important to check local validation criteria.
Will my Local Planning Authority require specific information?
Yes. Each authority has its own validation requirements. For example, you can review tree and planning guidance via your Local Planning Authority such as
https://www.staffordshire.gov.uk
to understand local expectations for arboricultural reports.
What is a Root Protection Area and why does it matter?
The Root Protection Area is the minimum area around a tree that must be protected to ensure its survival. An AIA assesses how development interacts with this area and sets out protection measures to prevent damage during construction.
Can construction take place near trees once an AIA is completed?
Yes, provided the recommendations within the AIA and any associated Arboricultural Method Statement are followed. These outline how works can proceed safely without damaging retained trees.
Who prepares an Arboricultural Impact Assessment?
An AIA should be prepared by a qualified arboricultural consultant with experience in planning and BS5837 assessments. This ensures the report is technically robust and accepted by Local Planning Authorities.
