Arboricultural evidence at appeal

Arboricultural evidence appeal cases are won on two documents: the tree survey the council said was inadequate, and a short, specific answer to each limb of the reason for refusal. Inspectors deciding tree cases are not looking for an argument that the trees do not matter. They are looking at whether the loss is necessary, whether the retained trees will survive the construction, and whether what replaces them is measurable. Get those three right and the appeal is straightforward. Miss one and no amount of survey detail will help.

Reading the reason for refusal

Break the refusal reason into its components before writing anything, because tree reasons usually contain three separate propositions bundled into one sentence.

The first is a valuation proposition: the trees have amenity value of a stated kind. The second is a causation proposition: the development would result in loss or damage. The third is a policy proposition: that loss conflicts with a named development plan policy and is not outweighed.

Each needs a different kind of answer. Valuation is contested with survey data and public visibility evidence. Causation is contested with drawings, method statements and root protection area arithmetic. Policy is contested with the plan wording and the balance. A proof of evidence that answers all three as a single narrative tends to answer none of them clearly.

Note also which duty the council relied on. Section 197 of the Town and Country Planning Act 1990 requires a planning authority, when granting permission, to ensure that adequate provision is made for the preservation or planting of trees where appropriate, and to impose conditions accordingly. A refusal grounded in that duty is a refusal about adequacy of provision, which is a different case from one about the intrinsic value of a single tree.

Disputed categorisation at appeal

BS 5837:2012 categorisation is where most tree appeals get technical, and where the appellant most often overreaches.

The categories describe quality and estimated remaining contribution: A for trees of high quality with an estimated remaining contribution of at least 40 years, B for moderate quality with at least 20 years, C for low quality with at least 10 years, and U for trees that should be removed for sound arboricultural reasons. The subcategories record whether the value is arboricultural, landscape or cultural.

Two disciplines matter. Do not recategorise a tree downwards without stated defects observed on site and recorded, with photographs. An inspector who sees a category B tree in the council's evidence and a category C in yours, with no defect described, will prefer the council's.

And remember that category is not the same as amenity. A category C tree in a front garden, visible from the length of a street, can have more public amenity value than a category B tree in a back garden nobody sees. Planning Practice Guidance on tree preservation orders treats visibility and wider impact as central to amenity, so lead with the visibility evidence rather than with the category letter.

Where the disagreement is about condition rather than category, offer the decay detection evidence. A resistograph or sonic tomography result, with the operator and date, settles a dispute that two opinions cannot.

Quantifying harm from canopy loss

Assertions about harm carry very little weight. Numbers carry a lot, and most of them are easy to produce.

Report the existing canopy area on site in square metres, the area lost, the area retained, and the percentage change. Report the number of trees by category before and after. Where the council's policy sets a canopy cover target, express the result against that target.

Amenity valuation systems such as CAVAT and the Helliwell method give a monetary or point-based figure for a tree, and they are used in evidence at appeals. Be careful with them. They are not policy, inspectors treat them as one input among several, and an appellant who leads with a low valuation for a prominent tree looks as though they are trying to price away a planning objection. Use them to show relative value between trees, which is what they are good at.

Root protection area incursion should be reported as a percentage of the area, per tree, with the position of the incursion relative to the stem. An unquantified incursion is read as an unmanaged one, and the Arboricultural Impact Assessment is where those figures belong.

Replacement planting as mitigation

Replacement planting is the mitigation inspectors accept, and it is also where the weakest evidence is usually offered.

Three things make it credible. Species and stock size stated, with the mature canopy each is expected to reach. Rooting volume provided per tree, so the planting can actually achieve that canopy. And a planting and maintenance specification with a replacement obligation for failures over a defined establishment period.

Be honest about the timescale. A 20-metre mature canopy cannot be replaced by a nursery stock tree within the life of the permission, and pretending otherwise invites the inspector to discount the mitigation entirely. The stronger position is to state the deficit, state when the replacement planting reaches parity, and argue the balance with that deficit in view.

Where the scheme can deliver more canopy than it removes over 20 or 30 years, show the calculation. Where it cannot, say so and rely on the other benefits. The detail of how those obligations are secured is covered in replacement planting conditions after tree loss.

Conditions offered in advance

Offer the conditions in the statement of case rather than waiting to be asked. It changes the inspector's options.

• Approval and implementation of an arboricultural method statement and tree protection plan, referenced to specific drawing numbers.
• Arboricultural supervision at defined stages, with a monitoring schedule and a reporting requirement to the authority.
• A tree protection fencing condition tied to a drawing showing the construction exclusion zone.
• A landscape and planting condition with species, sizes, positions and a five-year replacement obligation.
• A condition, to be met before development starts, requiring service routes within any root protection area to be agreed.

Drafting them properly does two things. It removes the inspector's concern that the retained trees will be damaged during construction, which is often the real reason behind a refusal. And it demonstrates that the appellant has thought about delivery, which affects how the rest of the evidence is read.

Site visit preparation for tree cases

Tree appeals turn on what the inspector sees, more than most other categories of appeal. Prepare the site accordingly.

Tag the trees with their survey numbers, visibly, in weatherproof form. Provide a plan with the tree numbers, the root protection areas and marked photograph positions, and take the photographs from those positions so the inspector can stand in the same place. Mark the proposed building footprint on the ground with pegs and tape where the site allows it.

Then think about the views. An inspector will look at the trees from public vantage points, because that is where amenity is experienced, so identify the vantage points and include them. Where the trees are barely visible from anywhere public, the photographs from those positions are your best evidence, and they are more persuasive than any amount of text.

Practical points people forget. Confirm access, including keys and any locked gates. Clear vegetation from tags. And where the case concerns a single tree, be certain everyone is talking about the same tree, which sounds absurd until it happens.

Where the inspector is likely to agree with the officer

It is worth being frank about the cases that do not succeed, because the time is better spent redesigning.

An inspector will usually side with the council where a category A tree of high public visibility is removed for a layout that could plainly have been arranged differently, where no arboricultural impact assessment was submitted with the application, where the method statement is generic and does not address the specific incursions, where root protection area incursions are unquantified, or where replacement planting is offered without rooting volume or species detail.

The common thread is necessity. Inspectors accept tree loss the site cannot avoid and resist tree loss that the design chose. So the strongest single piece of evidence in a tree appeal is usually a layout study showing the alternatives tested and why each failed, which is the same discipline described in the tree constraints plan and the layout it forces. A Landscape Strategy showing the replacement provision at maturity completes the picture.

PlanScope drafts an Arboricultural Impact Assessment and a Landscape Strategy from your site details and your arboricultural survey data, with "TO BE CONFIRMED" flags where survey figures are missing. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval. For specialist technical reports, qualified professional input may be required, and councils and inspectors expect arboricultural evidence from an author with recognised competence.

This is general guidance, not legal advice. Check the position with your local planning authority or a qualified professional before relying on it. Enter your postcode on PlanScope to see which reports a resubmission is likely to need.