Overshadowing from trees rather than buildings

Loss of light caused by a neighbour's trees is handled almost entirely outside the planning system. The daylight and sunlight methodology planners use assesses buildings, and it generally disregards vegetation, because a tree is not a permanent obstruction and light passes through a canopy in a way it does not pass through a wall. There is no right to light from a tree, and a council cannot serve a notice requiring a neighbour to reduce one simply because it shades your garden. The one statutory route that exists is the high hedges regime, and it is narrower than most complainants expect.

So the honest answer is usually not the one people want. That does not make the position hopeless.

Why the planning system treats trees differently

Planning controls development. Growing a tree is not development, so no permission was ever needed for the tree, and there is nothing to enforce against. Where a tree is protected by a Tree Preservation Order or stands in a conservation area, the control runs the other way: it restricts what can be done to the tree, not what the tree does to you.

The technical guidance follows the same logic. When an assessor models daylight to a window, existing trees are normally left out, on the basis that canopies are seasonal, semi-transparent and liable to change. That is a reasonable convention for a building assessment and it frustrates householders who can see, in July, exactly how much light the sycamore next door takes.

The high hedges complaint route and its limits

Part 8 of the Anti-social Behaviour Act 2003 lets a council deal with a complaint about a high hedge affecting the reasonable enjoyment of a domestic property. The criteria are precise, and most complaints fail on one of them.

• the hedge must be a line of two or more trees or shrubs
• it must be wholly or predominantly evergreen or semi-evergreen
• it must be more than two metres tall
• it must form a barrier to light or access
• the complainant must occupy a domestic property affected by it
• the complainant must first have tried to resolve the matter with the owner

A single large tree, however dominant, is outside the regime. A row of deciduous limes is outside it. A hedge affecting a commercial property is outside it. And a hedge on land with no identifiable owner or occupier is difficult to pursue.

Councils charge a fee to consider a complaint, set locally and sometimes substantial, and it is normally not refundable if the complaint fails. The council assesses whether the hedge is adversely affecting reasonable enjoyment, applying government guidance on how to measure the effect, and may issue a remedial notice requiring work and ongoing maintenance. Appeals go to the Secretary of State, and failure to comply with a notice is an offence.

Note that a remedial notice cannot require a hedge to be removed entirely, and it cannot reduce it below two metres.

Trees protected by an order, and the light argument

Where the tree is protected, you need the council's consent to prune or fell it, and as the affected neighbour you can apply, or ask the owner to apply. Loss of light is a consideration the tree officer will weigh against the amenity value of the tree, and it is not usually a winning argument on its own.

What strengthens it: dated photographs across the seasons, a note of which rooms and which times of day are affected, evidence that the tree has outgrown its position rather than simply grown, and a proportionate proposal. A request to reduce a crown by a stated amount, in accordance with the arboricultural standard for tree work, is far more likely to succeed than a request to fell.

Where consent is refused there is a right of appeal, and where the tree is not protected and not a hedge within the Act, the owner is free to leave it as it is.

Seasonal variation and deciduous canopy

Deciduous trees change the argument twice a year, and any assessment has to say which condition it describes. In leaf, a mature canopy can reduce light to a window substantially. Out of leaf, transmission through bare branches is much higher, so the winter months when daylight is scarcest are the months when the tree matters least.

That is the reason the high hedges regime is limited to evergreen and semi-evergreen species. It is also the reason a photographic record taken in August, on its own, overstates the annual effect. Take photographs in both conditions, dated, from the same position.

Where tree shading is a material consideration

Trees do enter planning decisions, in specific circumstances:

1. Where new planting is proposed as part of a development, the future shading of neighbouring windows and gardens is a material consideration, and a landscape scheme that puts a large forest species 3 m from a boundary can reasonably be objected to.
2. Where a development's layout relies on retaining trees, the resulting light levels to new dwellings are assessed, and an Overshadowing Study may be required.
3. Where an applicant seeks consent to remove a protected tree, the amenity balance includes the effect on neighbouring occupiers.
4. Where a condition requires replacement planting, the species and position can be discussed at the discharge stage.

So the effective moment to deal with tree shading is when a scheme is being designed or consulted on, not ten years later. Objecting to the species and position in a landscape plan is straightforward and often successful, as our note on rear extensions and overshadowing in dense terraces shows for buildings.

Evidence a complainant needs

For a high hedges complaint, assemble:

• photographs from inside the affected rooms and from the garden, dated, in both leaf conditions
• measurements of the hedge height and its distance from your boundary and windows
• a plan or sketch showing orientation, so the council can see which aspect is affected
• a record of the attempts you made to resolve it, with dates and copies of letters
• a description of what you can no longer do in the affected space

For a request to prune a protected tree, add the arboricultural specification of the work you are asking for, and, where the tree is large or close, a note from an arboriculturist on whether the reduction is achievable without harming the tree. A tree survey prepared to the British Standard is more than most householder cases need, and a short letter from a qualified arboriculturist is usually enough.

Remedies and what they cost

Abatement is the remedy people misuse. You may cut branches that cross your boundary, back to the boundary line and no further, and you must not cut a protected tree without consent even where it overhangs. Roots are the same. Cutting beyond the boundary, or damaging a protected tree, turns a grievance into a liability.

Where new development is the cause, enter your postcode on PlanScope to see which reports the scheme should have produced.

This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it.