Trees in third party ownership on a development boundary

A neighbour tree on a development boundary belongs to whoever owns the land the trunk stands on at ground level, and that ownership extends to the branches and roots that reach across onto your site. You can cut back growth that crosses the boundary under the common law right of abatement, but only as far as the boundary line, and only if the tree is not protected. If it carries a Tree Preservation Order or stands in a conservation area, that right is suspended until you have consent.

Who owns the tree, the branches and the roots

Ownership follows the trunk. A tree whose stem sits wholly on the adjoining land is the neighbour's tree even if three quarters of its crown is over your plot and most of its root plate is under your garden.

The parts that cross the boundary remain the neighbour's property. That has a practical consequence people find odd. Branches you lawfully cut off, and the apples on them, belong to the neighbour, so the orthodox position is that you should offer the arisings back rather than dispose of them. Most people will not want them. Offer anyway, in writing, because it removes an argument.

Where a trunk straddles the boundary the tree is jointly owned, and neither owner can carry out works without the other's agreement. Establish this from the title plan and a measured survey before you design anything, because an assumption here is expensive to unwind.

The common law right over overhanging growth

Abatement lets you remove the encroachment. The limits are narrow and worth stating plainly.

• You may cut back only to the boundary, not beyond it, and not into the neighbour's airspace.
• You may not enter the neighbour's land to do it without permission, as that would be trespass.
• You must not make the tree unstable or kill it, because that exposes you to a claim.
• The work should be done competently, to the standards a reasonable arboriculturist would apply.

A hard reduction to the boundary line on one side of a mature tree is often poor practice arboriculturally and can trigger exactly the decline that leads to a dispute. Commissioning the works through an arboriculturist, with a specification, costs less than defending a claim about a tree that died two seasons later.

Where a Tree Preservation Order changes the position

A Tree Preservation Order made under the Town and Country Planning (Tree Preservation) (England) Regulations 2012 prohibits cutting down, topping, lopping, uprooting, wilful damage and wilful destruction without the authority's consent. The right of abatement does not override it.

So an application for consent is needed even to reduce branches back to your own boundary. The exceptions are tightly drawn. Dead trees can be removed on five working days' notice to the authority. Works to remove an immediate risk of serious harm are permitted, with notice as soon as practicable, and the burden of proving the risk sits with you.

In a conservation area where there is no Order, section 211 of the Town and Country Planning Act 1990 requires six weeks' notice to the authority before works to a tree above the relevant size threshold. The authority can use that period to make an Order. Plan the programme around it rather than discovering it on site.

Roots, structural damage and nuisance

Roots are the part that causes real money to change hands. Encroaching roots that cause physical damage to a building or a structure can amount to a nuisance you can sue on, and the courts have accepted that the cost of remedial works can be recovered where the landowner has given the tree owner notice of the problem and an opportunity to deal with it.

Notice matters. A letter identifying the tree, the damage, the evidence and a request to act creates the record that a later claim rests on. Dealing with it quietly and then presenting an invoice is a weaker position.

Clay soils and highly water-demanding species are the usual combination behind subsidence claims. Where a new foundation is going in close to an off-site tree, the National House Building Council foundation depth guidance for trees and shrubs on shrinkable clay is the reference point the structural engineer will work from, and the foundation design should be settled before the layout is fixed, not after.

Getting access to neighbouring land

You have no general right to enter adjoining land to carry out works. The Access to Neighbouring Land Act 1992 allows a court to grant access for basic preservation works to your own land or buildings, which can cover works to a tree where they are needed to preserve something of yours. It is not a route to gaining access for development works.

In practice this is negotiated. An access licence setting out the dates, the working method, insurance, making good and a modest payment is the normal answer, and it is quicker than any court route.

Build the possibility of refusal into the design. If the scheme only works where a neighbour grants access to prune their tree, the scheme has a single point of failure outside your control.

Showing off-site trees on the survey

A survey to BS 5837:2012 covers trees on the site and off-site trees whose root protection areas, crowns or shade fall within it. Leaving the neighbour's oak off the plan because it is not yours is the most common failing in a householder submission.

The root protection area for a single-stem tree is a radius of 12 times the stem diameter, measured at 1.5 m, capped at 707 m², and it is drawn whether or not the stem is on your land. Where the area crosses the boundary, show it crossing. A tree survey that stops at the red line tells the officer nothing about the constraint that will actually shape the layout.

Shade should be plotted too. A tall tree on the southern boundary of a new garden produces a shading pattern that will be used against the amenity case, and it is better to design around it than to be told about it at consultation.

Designing for a tree you do not control

Three design responses, in order of preference. Pull the building footprint outside the root protection area. Where that is impossible, use a no-dig construction over a cellular confinement system for parking and access, which our note on scaffolding and site access within a root protection area explains in more detail. Where neither works, a precautionary foundation design agreed with an arboriculturist and a structural engineer is the fallback.

Service routes are the forgotten element. Trenches for drainage, water and power are what actually sever roots on a tight site, and an off-site tree gives you no option to fell. Our note on utility trenching close to trees sets out the alternatives.

Conditions will usually require an arboricultural method statement and a tree protection plan approved before work starts, protective fencing installed and photographed, and supervision at defined stages. Expect the authority to ask for protection of off-site trees on the same terms as its own, and in some cases for a financial guarantee, which our note on tree bonds secured through a planning obligation covers. A Landscape Strategy should show the retained off-site canopy as part of the green infrastructure rather than as an obstacle.

This is general guidance, not legal advice, and you should 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.