Specifying crown work so a contractor prices it correctly

Specifying tree works properly is what turns three wildly different quotations into three comparable ones. Say "reduce the oak" and you will get a price for taking a metre off, a price for taking three metres off, and a price for something close to topping. Say "reduce the lateral branches on the south and west sides by up to 2m, to leave a final crown spread of approximately 6m, in accordance with BS 3998:2010" and every contractor is pricing the same job. That sentence is also the difference between works that match your consent and works that do not.

If the tree is protected, the specification matters even more, because the council consents to the wording rather than to your intention.

Name the operation, not the outcome

BS 3998:2010 gives each pruning operation a defined name, and contractors read those names the same way. Use them.

Crown reduction shortens branches to reduce the overall size of the crown. Crown thinning removes a proportion of the smaller secondary branches throughout the crown to let light through, without changing the crown's outline. Crown lifting removes the lowest branches to raise the height of the crown above the ground. Selective pruning removes named individual branches. Pollarding cuts back to a framework and commits you to repeating the cycle every few years.

Topping is not on that list. Nor is "tidying up", "cutting back to the fence line" or "taking the weight off", all of which appear on quotations and none of which mean anything a second contractor can price. An arboriculturist will also tell you that reducing a mature oak or beech hard is a poor idea regardless of how it is worded, because the tree responds with dense regrowth on weak attachments. Ask for the operation you want and let the contractor tell you if the species will not take it.

Reductions in metres, not percentages

A percentage reduction is the single most common defect in a tree works specification. Reduce by 25 per cent of what: height, crown volume, leaf area, branch length? Each gives a different tree, and each gives a different price.

Express a reduction as a dimension. Two forms work.

The first states the branch length removed: "reduce all lateral branches by up to 1.5m, cutting back to a suitable secondary growth point". The second states the finished crown: "reduce overall height from approximately 14m to approximately 11m and crown spread from approximately 8m to approximately 6m". The words "up to" and "approximately" are doing real work there, because a cut has to land at a growth point capable of taking over, and BS 3998 is clear that pruning cuts should be made at a suitable branch or bud rather than at a fixed measured line.

For a tree covered by a Tree Preservation Order, put both forms in the application: the branch length and the resulting dimensions. Councils grant consent against the wording they were given.

Crown lifting and the clearances that matter

Crown lifting is the operation most often specified vaguely and most often disputed afterwards. Give the finished clearance height above a stated surface: "crown lift to give 2.5m clearance above the footway and 5.2m above the carriageway" is standard for a street tree, and those are the clearances a highway authority normally expects under its duties in the Highways Act 1980.

Over a garden the number is yours to choose. Somewhere around 3m usually gets a mower under a tree without leaving it looking like a lollipop. BS 3998 cautions against lifting the crown above about a third of the tree's total height, because removing the lower crown shifts the centre of gravity, exposes the trunk and rarely improves the tree. If the brief is really "I want light on the lawn", thinning or a modest reduction on one side may do more.

Where the tree overhangs a neighbour, say so in the specification and agree access in writing first. Branches and fruit removed under the common law right to abate an overhang remain the neighbour's property, which is an awkward conversation to have from the top of a ladder. Trees near a boundary raise other questions too, including trees and subsidence claims on neighbouring property.

Deadwood and thinning

Deadwood removal should be specified by location and size, not as a blanket instruction. "Remove deadwood over 50mm diameter from over the patio and the parking area, retaining deadwood elsewhere" is defensible. "Remove all deadwood" strips out habitat for no safety benefit and costs more.

There is a legal edge to this. Standing deadwood and cavities in mature trees are the commonest bat roost features in a garden setting, and all bat species and their roosts are protected under the Wildlife and Countryside Act 1981 and the Conservation of Habitats and Species Regulations 2017. If a contractor finds a roost feature, work has to stop. On anything larger than a small garden tree, a pre-works check by someone competent is sensible, and a full bat survey may be needed before the saws come out.

Thinning is the one operation where a percentage is the right unit, because it describes the proportion of secondary branches removed rather than a dimension. Keep it modest. Thinning much beyond 30 per cent tends to produce a crown that looks sparse for a season and then regrows denser than before.

Arisings, stumps and putting the garden back

Half the price difference between quotations sits in what happens after the cutting stops. Specify it.

1. Arisings: chipped and removed from site, chipped and left on site as mulch, or logged and stacked. Removal costs more and is the default assumption unless you say otherwise.
2. Stumps, where a tree is being felled: ground out to a stated depth, ground out and backfilled with soil, or left. Grinding to around 200mm below finished level is enough for turf but not for a patio.
3. Access route and protection: whether the crew are crossing a lawn, a new drive or a flower bed, and what protection is expected.
4. Reinstatement: turf, topsoil and the state you expect the site left in.
5. Waste: confirmation that green waste is going to a licensed facility, which also matters if the tree shows signs of disease.

A short sketch plan with the trees numbered saves more argument than any amount of text. Number them the same way as any tree survey already prepared for the site, so the survey, the consent and the quotation all refer to the same tree.

Who you are letting up the tree

Check three things before accepting a price. Public liability insurance with the sum insured stated, and confirmation that it covers aerial tree work rather than groundworks only. Chainsaw and aerial rescue certification for the operatives who will climb. And membership of a recognised arboricultural body, which is the most efficient shorthand for the rest.

Ask for the quotation to restate your specification rather than paraphrase it. A contractor who rewrites "reduce laterals by up to 1.5m" as "reduce crown" is telling you something.

Matching the specification to the consent

This is where householders come unstuck. If the tree is covered by a Tree Preservation Order, you need the council's consent before work starts, and carrying out works beyond the consent is an offence under section 210 of the Town and Country Planning Act 1990. If the tree stands in a conservation area and is not already covered by an Order, section 211 requires six weeks' written notice to the council before the works, giving it the chance to make an Order.

So the sequence runs: agree the specification, apply or notify using that exact wording, wait for the decision or the six weeks, then instruct the contractor against the consented text. Where the council grants consent with amended wording, reissue the specification to match before work begins. Where works form part of a development scheme, they also need to sit inside whatever the approved Landscape Strategy and tree protection details say. The related question of pruning specifications and writing them properly goes further into cut placement and timing.

Draft the tree documents for a planning application on PlanScope by entering your postcode, then have an arboriculturist check the specification against the consent.

This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.