Trees in Development

National and local policy for trees

We have set out how national policy cascades to local policy in this section.  Please note:

• this is not a comprehensive list
• policies may change from time to time

National policy

The National Planning Policy Framework (NPPF) recognises the importance of trees for placemaking and the climate. Key points in NPPF paragraph 131 are:

• new streets should be tree-lined
• incorporate trees elsewhere in developments (such as in parks and community orchards)
• put measures in place to secure the long-term maintenance of newly-planted trees
• keep existing trees wherever possible.

NPPF paragraph 180 discusses Ancient Woodlands.

Local policy

Cornwall Council’s Local Plan includes trees under Green Infrastructure. Policy 25 aims to protect and enhance Green Infrastructure including trees.

Proposals should consider long-term maintenance.

Policy 23 protects Ancient Woodland and Veteran Trees.

Cornwall Council's Climate Emergency Development Plan Document (DPD) covers trees in:

• Policy G3 Canopy - creates new requirements for canopy cover on development from 15 June 2023
• Policy G1 Green Infrastructure - refers to Street Tree requirements.

Climate Emergency DPD Policy G2 also references Biodiversity Net Gain (BNG), to which trees contribute unit scores. Early consideration of trees in relation to BNG will help to maximise benefits.

Tree planting supports:

• Cornwall Council's ambition to become carbon neutral
• A thriving, sustainable Cornwall with a great environment for all

Guidance for developers and their agents

The Council has a duty to make arrangements for the protection and planting of trees in new developments.  A proposal's design should include existing and new trees.  It should make sure they compliment and integrate with the development.  We will look for proposals that enable both:

• successful long-term retention and
• establishment of trees in developments.

You can read our planning approach to integration of trees into developments in our note on Trees and planning.

Design

We recommend you use our pre-application advice service before submitting a planning application. If a development is likely to impact trees, everyone involved should discuss solutions early on. Design teams should work together from the start of the project (RIBA 0/1) on integrating existing and new trees into developments. The team should at least include:

• arboricultural consultant
• ecologist
• landscape architect
• utility and civil engineers and
• architect.

Designs must be developed based on a full understanding of the constraints. Developers should consider tree survey findings and constraints plans. We recommend best practice guidance such as the Trees and Design Action Group (TDAG). This will help successfully integrate trees into developments.

Where trees are either on the site or on land adjacent to the site, your planning application should have:

• a tree survey
• a Tree Constraints Plan and
• a Tree Protection Plan.

These should follow British Standard 5837: Trees in relation to design, demolition and construction - Recommendations.

Layouts and Construction Exclusions Zones

When designing a layout where trees are nearby, you should:

• keep important trees wherever possible
• consider below and above ground. This means roots, rooting areas and the canopy.
• define and incorporate Root Protection Areas into proposal
• predict and plan for future tree growth
• protect retained trees within a Construction Exclusion Zone (CEZ).

Please note:

• all works must occur outside the CEZ. This includes development and enabling works.
• machinery must not access the CEZ
• you should not store materials in the CEZ
• you must not strip soil and
• levels must remain unchanged.

Developers should make sure there is enough space. The development should be carried out without impact on the CEZ.

New properties will need to be in harmony with retained and newly planted trees. This is so that new occupants are not caused unreasonable inconvenience. For example, by shade or overhanging branches.

Officers may include tree-related planning conditions in a planning consent. Please discuss requirements with your planning officer.

Trees in highways and adopted areas

There are specific requirements for tree planting in highways and open spaces to be adopted.  This is to reduce potential conflict between trees and highways which include:

• roads
• footpaths
• utility corridors.

Adopted infrastructure is maintained at public expense.  Correct designs and specifications of tree planting are key to:

• avoid adverse effects on adopted infrastructure
• minimise and manage maintenance costs in the interest of public finance.

Cornwall Council’s Highways & Infrastructure Adoptions team are involved at Technical Approval stage. This is not normally until a development is ready to start. It can be months or years after gaining planning approval. Developers and their design teams should fully consider adoption requirements at design stage. This will make sure that tree planting specified at planning stage:

• is adoptable and
• can be done as planned.

Key considerations include:

• distance of trees from kerbs and potential need for root barriers
• tree locations and road safety. It includes visibility splays and obstruction of lights, CCTV and road signs.
• creation of rooting soil areas and volumes. These may need crates or special pavement construction.
• commuted sums for trees, and
• the type of trees specified. This includes species and size. This affects parking and road safety, maintenance costs and user amenity.

This list is not exhaustive.

You can find guidance and contact details using this link: Highway and infrastructure adoptions.

There is information from the Manual for Streets and Manual for Streets 2. These both contain some guidance for trees in highways.

Trees and Utilities

Statutory undertakers have a general licence to carry out certain development and highways works. These companies and agencies include utility companies (electricity, gas, water, sewage, electronic communications). Other public bodies as well, for example:

• Post Office
• Civil Aviation
• railway companies
• the Environment Agency.

Utility companies are those most often involved in new developments. We recommend developers and their design teams liaise with utility companies early. Impacts of utility corridors and their buffers on existing and new trees in masterplans need review at planning stage.

Exceptions and exemptions

Certain exceptions to tree protection may apply to statutory undertakers.  Exemptions are as follows.

Trees can be:

• cut down
• topped
• lopped, or
• uprooted by or at the request of a statutory undertaker.

This is:

• without the need to seek prior approval from the Council
• where the land on which the tree sits is operational land and the work is necessary.

It may be necessary:

• so they can work safely
• relating to inspection, repair or renewal of any sewers. This includes mains, pipes, cables, other apparatus of the statutory undertaker.
• to enable them to carry out development under the Town and Country Planning (General Permitted Development) Order 1995.

In these circumstances the necessary work may continue without consent from Cornwall Council. The statutory undertaker or their contractor must be able to show that:

• the work was an exception if challenged and
• they would be expected to work within the remit of BS3998-Tree Works-Recommendations and take account of the NJUG4 guidance.

This is to minimise any adverse impacts on trees.

Whilst there are these exceptions for certain tree works, utility companies should have regard to guidance, standards and legislation.

National Joint Utilities Council Guidance

Guidance is set out in National Joint Utilities Council (NJUG) publication Volume 4. It is NJUG Guidelines for the Planning, Installation and Maintenance of Utility Apparatus in Proximity to Trees.  There is also an Operatives Handout. You can download this and other utility guidance for free from Publications - Streetworks.

NJUG4 states:

“Site surveys should be undertaken appropriate to the scale of the planned works. These surveys will identify the presence of trees which could impact on works. Advice should then be sought from a local authority tree officer. ... Site surveys should be carried out according to the recommendations within BS 5837”.

Tree planting, establishment and maintenance

Applicants need to consider tree planting and establishment on a site-specific basis. You should:

• submit enough information to enable assessment at planning stage
• make reference to best practice guidance.

Correct planting and establishment care are important for healthy growth of trees. This includes but is not limited to:

• Subsoil preparation
• Drainage
• Tree pit design
• Rooting soil volume enough for mature tree requirements
• Consideration of species choice, canopy spread, distance to buildings and windows and overshadowing
• Establishment provisions in place for at least the first five years.

Tree maintenance work should follow BS3998, Tree Work Recommendations. Maintenance in adopted highways and public spaces will be greater. You should use professional risk assessments and surveys to inform requirements.

Standing and fallen deadwood supports a wide range of species. You should consider keeping standing and fallen deadwood in appropriate areas. For example, in native tree and shrub planting areas.

The Woodland Trust provides some guidance on this subject.