B2.5.1 Tree planting, street trees and landscape design

All new trees, of whatever size (including those proposed for hedgerow planting and woodland creation), must be procured and planted in accordance with British Standards BS 8545:2014, with the nursery provider demonstrating Plant Healthy Certification and/or an adopted biosecurity policy.

New tree planting must allow trees to reach full maturity without compromising their health, structural integrity, or causing future conflicts with buildings, utilities, CCTV, lighting, operational requirements or public safety.

Proposals must demonstrate that adequate space is provided above and below ground, including sufficient rooting volume, suitable soil conditions, and unobstructed canopy space, which must be fully considered in line with the tree variety at maturity.

All new developments should integrate street trees and additional tree planting within areas of opportunity within the sites design proposals. This helps to improve climate resilience by providing shade, reducing heat, improving air quality, enhancing biodiversity, softening hard landscaped areas, helping address issues of flood risk and stormwater run-off, increasing economic value, positive health and wellbeing effects.

Street tree placement and type should also reflect the street hierarchy and be spaced at regular intervals (generally no more than 15 metres apart on average) to ensure consistent canopy cover and a cohesive streetscape. Further guidance should be sought from the Street Hierarchy section within Chapter B4.

Street tree planting must not cause obstruction to those walking, wheeling and cycling (walkers, cyclists, horseriders and other non-motorised users). Street trees can be adopted:

• in the carriageway in build outs (details of the proposed build outs will need to be confirmed) to maintain the minimum footway widths as identified in (Street hierarchy section in Chapter B4)

• in grass verges (with a minimum verge width of 1 metre) or on the edge of the footway

In all instances the minimum footway widths must be maintained.

Development proposals must prioritise locating proposed street tree planting within the public realm (such as streets, parks and open spaces), and not purely within front gardens of new properties and buildings.

Exception: Only where it can be adequately demonstrated that engineering solutions cannot be incorporated to include trees within highway verges. Trees located within front gardens of new properties or buildings, may be considered as alternatives to street tree planting.

All new major developments should deliver increased urban tree canopy cover through retaining existing trees and/or establishing new planting, with a total canopy coverage equal to at least 18% of the site area (excluding areas of the site that are priority habitat types). Where a site already exceeds 18% canopy cover, development should not result in a net loss of canopy cover.

New tree planting should be designed to enhance ecological connectivity across the site, creating stepping-stone habitats that link fragmented green spaces. This contributes to a cohesive and resilient green infrastructure network, supporting biodiversity by enabling the movement of species and the spread of native flora.

Tree species should be selected in line with the listed guidance documentation set out below. This means selecting trees that have a clear purpose in delivering canopy cover, biodiversity, climate resilience, or amenity benefits and are well-suited to:

• the local landscape character

• historic context

• specific planting locations

• the soil conditions so that trees can establish and thrive, whilst also ensuring that they do not undermine soil characteristics that support important habitats

For further guidance on appropriate species selection, refer to:

• Tree Species Selection for Green Infrastructure: A Guide for Specifiers (Trees and Design Action Group - TDAG)

• First Steps in Canopy Cover Assessments (TDAG)

• First Steps in Urban Tree Canopy Cover (TDAG)

• First Steps in Urban Water (TDAG)

• Urban Tree Manual (Forest Research)

• Right Tree, Right Place, Right Reason (Forestry Commission)

Design of new woodland areas, as well as supplementary or replacement tree planting, should use species of local provenance and should be located adjacent to existing habitats. This approach supports wildlife connectivity, enhances stepping stone and buffer habitats, and contributes to broader ecological networks.

Development proposals should be designed to meet the following standards set out within ‘Building with Nature Standards Framework’:

Core Standards

• Standard 2 Positively responds to the climate emergency

• Standard 5 Creates distinctive places

Wellbeing Standards

• Standard 7: Brings nature closer to people

• Standard 8: Supports equitable and inclusive places

For all proposed trees in hard landscape areas and other constrained locations (such as highway verges or planters) a detailed tree pit specification must be provided as part of the application. This must set out the soil type and soil volume required for each tree species to ensure healthy growth from establishment to maturity. Specifications must also demonstrate how the design will protect surrounding infrastructure, including utilities, footpaths, and highways.

Where trees are to be planted in paved or hard landscape areas, each tree pit should be surfaced with a permeable layer of resin-bonded gravel (coloured to complement the surrounding paving) or a self-binding gravel such as hoggin. Any bonded gravel or paving should be laid level with the surrounding footway and the base of the tree, with no upstand at the pit edge. Paved or integrated tree grilles may also be used where appropriate, provided they are designed to be flush with the surrounding footway and allow for future trunk growth without creating trip hazards or maintenance issues. Traditional metal tree grilles should generally be avoided as they can create a litter trap which is difficult to maintain effectively.

Tree lighting in new urban and public realm projects should avoid wrapping trunks or branches with wiring or hanging lights directly from trees, as this can damage bark, restrict growth, and be difficult to maintain. Instead, integrated surface-mounted uplighting or ground-level architectural lighting should be used to create visual interest.

Where practicable, tree pits should be designed to include sustainable irrigation by capturing stormwater run-off through Sustainable urban Drainage System (SuDS) features to support healthy establishment and long-term growth.

All proposed tree and hedgerow planting (excluding those in private gardens) must be accompanied by a management plan that includes provisions for replacing any failed plants for at least five years after planting to ensure successful establishment and longterm resilience.

The landscape and planting strategy should be developed in coordination with the street hierarchy, recognising that planting forms a key component of a street’s character and identity. Tree selection should be guided by the spatial context to ensure long-term suitability and healthy growth:

• small to medium-sized trees, or fastigiate form trees, are most appropriate for limited spaces such as courtyards and narrower streets

• larger tree species should be reserved for more generous settings, including wide avenues, parks, grass verges, and other open landscaped areas

Further guidance should be sought from the Street Hierarchy section within Chapter B4.

The landscape strategy must include a clear narrative describing how the proposed development is integrated within the surrounding landscape, including natural landscapes and urban townscapes.

Landscape design must be conscious of operational and safety needs, ensuring sufficient access to operational assets such as lighting columns, feeder pillars, road signs and street furniture. Proposed tree planting and landscaping must not be located within visibility splays to ensure visibility for drivers, cyclists and pedestrians is not compromised.

Exception: Applicants can consider the provision of low-level shrub planting within visibility splays and forward visibility envelopes. Selected shrub species must only have a maximum potential growth height of 1 metre (above the nearside carriageway channel or 0.8 metres above the footway).