Evidence base

The treescape

The Preston City Council local authority area covers approximately 14,295ha and encompasses a varied pattern of land use, ranging from urban residential zones in the south to rural agricultural land in the north. Across the area, there is approximately 1,528ha of tree canopy cover, comprising individual trees, tree groups and areas of woodland which this strategy describes as the 'treescape'. This includes trees growing on both public and privately owned land.

Preston City Council owns and manages approximately 8% of the land located within the local authority area, which mainly comprises public parks and public open green spaces. Overall, 17.8% of trees are on Council owned land which means that whilst the Council is a major stakeholder, trees in private ownership are a major component of the treescape.

Preston City Council operates within a two-tier authority system meaning that local government functions are split between the county Council and the city Council. Preston City Council is responsible for managing all the trees that exist on land that is within its ownership, whereas Lancashire County Council is responsible for the majority of highway trees. Preston City Council does not manage these trees.

There are also 9 parish Councils within the Preston City Council area. Parish Council areas are located in an arc across the north of the city and are predominantly rural in nature with the exception of Ingol and Tanterton. Parish Councils contribute to the management of public areas including works to trees. Many also own and manage their own tree populations or contract works out to external trusts and organisations. Most rural parishes have multiple stakeholders with an interest in the treescape.

Canopy cover

Canopy cover is a two-dimensional measurement which refers to the total area of a tree when viewed from above. Measuring canopy cover is an effective way of assessing the extent and distribution of an existing tree population. It can provide a framework for policy development, assist decision makers, and help members of the public to better understand and visualise the treescape.

Understanding the existing canopy cover provides the Council with a baseline against which changes in the treescape can be measured over time.

Bluesky National Tree Map data was used to assess existing canopy cover for the production of this document. This data provides the location, height and canopy extents for individual trees greater than 3m in height. This data was used to determine canopy cover overall, per ward and within Council ownership, reported as a percentage.

Canopy cover for the whole Preston City Council area is 10.7%, which is below the average canopy cover for towns and cities in England (16.4% mean or 15.8% median). Canopy cover of 20% is emerging and increasingly widely accepted as an appropriate minimum target for local authorities. Therefore, the current canopy cover falls short of what should be considered 'fit for purpose' in terms of delivering public objectives such as biodiversity, amenity, recreation, ecosystem services, food production and carbon sequestration.

A previous i-Tree Canopy study estimated canopy cover for Preston at 14.6% (+/- 1.58). This is higher than the current National Tree Map data suggests but the figure represents only the city of Preston, omitting some of the more rural northern areas where canopy cover is particularly low. This figure confirms a below average canopy cover in both urban and rural parts of the local authority area and is broadly consistent with the more recent findings.

Tree cover is unevenly distributed across the local authority area. The densest tree cover occurs along waterways including the River Ribble, Tun Brook, Savick Brook, Sharoe Brook and Lancaster Canal. Tree cover is limited on rural agricultural land in the north and there are low levels of street tree planting within the city centre and some residential wards in Preston. Woodland cover is also relatively limited and National Forest Inventory data for Lancashire suggests that overall woodland cover for the county was 6.6% at the time of the assessment, indicating that the area follows a wider regional trend of low woodland cover.

The majority of Council owned trees are located within public parks and open green spaces. Whilst overall canopy cover is low, canopy cover on Council owned land is significantly above average, largely because of the proportion of parks and open spaces within the overall Council estate.

Benefits, services and value

The role of the Council includes the delivery of services to people. Planting new trees and maintaining the existing treescape is a cost-effective way to generate public benefits. Trees provide a wide range of benefits and services including improving air quality, increasing flood resilience, encouraging outdoor activity, improving mental health and providing visual amenity.

A high quality treescape can deliver substantial public benefits, goods and services, and reduce service demand in other areas such as healthcare.

Trees also play a vital role in increasing resilience to climate change. Ecosystems services provided by trees, such as carbon sequestration, stormwater interception and urban cooling, can help to mitigate the effects of our changing climate.

Improving the treescape will also help to address the biodiversity crisis that we are facing by increasing habitat provision, improving habitat connectivity, and enhancing habitat value.

These types of benefits are increasingly understood and valued, including by the public. It is tempting to explore how such benefits might be maximised by modifying ongoing practices, such as tree planting. However, the scale of available benefits through treescape enhancement cannot be realised by 'finessing'; cultural and systemic change is needed, and a comprehensive increase in ambition. Benefits are not shared equally at present because of geographical disparities in tree cover and this should strongly inform both the opportunity mapping and delivery of corrective measures.

Relevant policies, strategies, and guidance

National

In 2019, the Government declared an environment and climate emergency in response to the rapid change in climate being experienced around the world. In the same year, Preston City Council declared a climate emergency, pledging a target that its own activities will be net zero in terms of carbon emissions by 2030 and that it will work with other stakeholders to make the city zero carbon by the same date.

The Climate Change Act (2008) outlines the Government's proposed response to climate change and the underlying principles have been incorporated into the National Planning Policy Framework (NPPF), providing guidance to local authorities on how to translate this into policy.

In 2021, the Government published the England Trees Action Plan 2021-2024 (ETAP) which sets out the long-term vision for trees, woodlands and forests in England and the actions required to achieve this, highlighting the important role that trees can play in tackling climate change.

The ETAP builds on the ambitions established in the 25 Year Environment Plan which sets out how the Government aims to improve the state of the natural environment over the next two and a half decades.

To help deliver the Government's aims regarding biodiversity, legislation has been passed in the form of the Environment Act 2021, which enshrines in law a duty to conserve and enhance biodiversity, including by considering what actions can be taken to further this objective; a requirement for new developments to achieve 10% biodiversity net gain; and strengthened controls on the felling of street trees, placing a duty on highway authorities to consult with the public before felling a tree on an urban road.

The National Planning Policy Framework (NPPF) sets out policy guidance regarding the protection of trees and woodland. Planning policies and decisions made by local authorities are expected to contribute to and enhance the natural and local environment by protecting valued landscapes, providing net gains for biodiversity and also by recognising the ecosystems services that can be provided by trees and woodlands.

In the determination of planning applications, if significant harm to biodiversity resulting from a proposed development cannot be avoided, mitigated, or compensated for, then planning permission should be refused. Emphasis is also given to the protection of irreplaceable habitats including ancient woodland and veteran trees; development resulting in loss or deterioration of these should be refused unless there are wholly exceptional reasons.

Tree planting is recognised as an effective way to help towns and cities mitigate and adapt to climate change. In 2021, the NPPF was updated to give more weight to the importance of urban tree planting, stating that new streets should be tree-lined, opportunities should be taken to incorporate trees into developments and measures should be taken to ensure long-term maintenance of new trees and retention of existing trees wherever possible.

There are a number of British Standards which set out best practice guidance for some activities relating to trees:

• BS 3998:2010 Tree work - Recommendations
• BS 5837:2012 Trees in relation to design, demolition and construction - recommendations
• BS 8545:2014 Trees: From nursery to independence in the landscape - recommendations
• BS 3936-1:1992 Nursery stock - Specification for trees and shrubs
• BS 3882:2015 Specification for topsoil
• BS 8601:2013 Specification for subsoil and requirements for use

Local

The current Preston Local Plan 2012-2026 sets out site allocations and development management policies based on the strategic policies set out in the Central Lancashire Core Strategy. The Local Plan aims to ensure that appropriate forms of development occur in the most suitable locations. It contains the following policies of relevance to trees:

• Policy HS3 Green Infrastructure in New Housing Developments
• Policy EN2 Protection and enhancement of Green Infrastructure
• Policy EN3 Future Provision of Green Infrastructure
• Policy EN10 Biodiversity and Nature Conservation

The Central Lancashire Core Strategy sets out principles for the management of sustainable development in the area. It contains the following policies of relevance to trees:

• Policy 18: Green Infrastructure
• Policy 22: Biodiversity and Geodiversity

The Preston Parks and Green Spaces Strategy 2021-2031 sets out the Council's aims to improve parks and green spaces. The Strategy focuses on improving and maintaining eight key park sites, making recommendations on how the use of allotments can be maximised, considering how best to enhance tree coverage and ensuring that biodiversity is at the core of future decision making.

The Central Lancashire Biodiversity and Nature Conservation Supplementary Planning Document (2015) sets out the approach as local planning authorities towards conserving, protecting, and enhancing biodiversity and ecological networks and provides guidance for applicants in terms of understanding the relevant Central Lancashire policies and what is required as part of the planning application process.

The document aims to ensure that there is no net loss of nature conservation assets, and where appropriate, there is an improvement.

Legal duties and statutory functions

Legal duties

As well as helping to deliver the wider aims of Government policy, local authorities have a number of legal duties in regard to trees, woodland and biodiversity.

Through policy and consenting, and the management of its own land, the Council has a duty to conserve and enhance biodiversity. Any proposed works which may affect protected species must also comply with relevant legislation.

The Council duties of care under statute and common law with regards to the safety of its trees. As a tree owner, the Council must take reasonable care to avoid foreseeable acts or omissions which may result in harm or injury and to ensure that visitors to their land, including those who are not authorised to be there, will be safe from harm. When carrying out its activities, the Council must also comply with the relevant health and safety legislation to ensure that, so far as is reasonably practicable, employees and members of the public are not put at risk.

With regards to trees outside of their ownership, the Council may deal with problem trees in some situations which are located on private land, such as where it overhangs a road or footpath and causing an obstruction or posing a danger to the public.

Statutory functions

Local authorities have a statutory duty to provide certain services to their residents. This includes the provision of planning and development services, and housing services, both of which have the potential to influence the treescape.

The Council has a responsibility to house its residents. This could involve building new homes, enabling housing in existing residential property, or acting as landlord for residents in Council owned homes. In 2005, the Council transferred its housing stock, along with trees present in private gardens and communal spaces, to the control of the Community Gateway Association. All housing associations across the local authority area are responsible for managing their own tree populations.

The Council also provides planning services to the public, including producing local development documents to allocate land use and guide development, determining applications for planning permission, making Tree Preservation Orders (TPO), and regulating works to TPO trees and trees within conservation areas. There is immense potential for the Council to shape the treescape through its role as a consenting authority, which intersects with a more substantial range of activities and resources than the Council controls directly.

All local authorities must have an up-to-date local plan which sets out planning policies for the local area to guide applicants and decision makers. This should include policies which relate to the protection and enhancement of the treescape in line with national policy and the law. All trees are a material consideration in planning applications and the Council has a responsibility as decision maker to ensure that trees are given due regard when determining applications.

Consultation

Identifying stakeholders

To inform the production of this Strategy document, key stakeholders were identified. Organisations or people involved in the delivery of relevant activities, or with a significant and relevant external perspective were shortlisted. These included individuals from the Council's Parks and Planning departments; a range of technical, management, support and administrative staff; elected members; representatives from the parish councils, Lancashire County Council, Chorley Council and South Ribble Borough Council; Friends Of groups from local parks; local environmental charities; and housing associations.

Methodology

Key stakeholder's opinions were captured during in-person and on-line interviews and workshops, exploring the intersection between respective stakeholders' areas of expertise and interest and trees. These were chaired discussions of approximately an hour including up to 7 people. Workshops collected views on the number, distribution, health, benefits and management of trees within the area and aspirations for the future.

The sessions also explored barriers to, and ways to achieve, improvements in the quality, functionality and management of the treescape. In total, 34 people from 15 organisations were involved in the consultation.

The consultation sessions were chaired by TEP. Sessions were recorded. Notes and transcriptions were processed, and all data was anonymised.

The views of the general public were also explored via an on-line questionnaire during July and August 2022. This was sent out to community groups on social media platforms via Preston City Council, and directly to local organisations for circulation but responses were submitted by individuals. 253 responses were received.

Data from the public consultation was in the form of ten questions, including a mix of closed, open and multiple-choice questions.

Emerging Themes

The stakeholder consultation covered wide-ranging topics, with individuals giving detailed comments in relation to their respective experience, expertise and perspective. Throughout these observations, significant themes emerged which are useful to characterise the current situation, perspectives, and challenges or aspirations. These aggregated themes are the primary finding of the consultation with key stakeholders and are outlined below.

There is no clear direction, strategy or vision for the treescape. Organising principles for tree management and planting would be desirable. Leadership and coordination are weak, particularly multilaterally. There is an appetite for a shared vision for local partners to rally behind and work towards.

There are significant opportunities to modernise systems, tools and processes to improve efficiency and add value in many areas of local authority tree management. A reactive 'asset management' approach is limiting; a proactive and vision-led approach is preferred.

The multi-tier authority structure presents a particular set of challenges to management and enhancement of the treescape. Relevant resources, land, systems, skills and information are disaggregated through county, parish, neighbourhood and city councils. This can limit economies of scale, make public engagement and communication more difficult, add complexity to delivery of new projects, and create barriers or inertia.

The planning system should embed and ensure delivery of improvements to the treescape, through tree planting, appropriate tree protection, and securing resource provision for tree and woodland management. Planning should be a major vehicle for positive change, but it is not. Policy and guidance are vague, not applied consistently, poorly understood, and not enforced. There are significant opportunities but realising them will require political support, coordinated action, and a change of approach.

Net positive development outcomes are not currently guaranteed.

There is widespread and growing appreciation of the environmental, biodiversity, health, and economic benefits that trees and green infrastructure deliver.

The level of consultee awareness of related topics such as climate change, biodiversity loss, and threats to trees from pests and diseases was high. There is strong and widespread support for increased canopy cover within the area, as well as support for establishing canopy cover targets to facilitate action on treescape.

Consultation data and transcripts of consultations are not included in this Strategy for data protection and anonymity reasons.

Public perception and support for action

The public consultation focussed on how the treescape is valued and understood, and what it should be like. The responses demonstrated a high level of engagement with the topic, with over 90% of respondents indicating that trees were very important to them: trees matter very much to many people.

A large majority of respondents (83%) thought that tree canopy cover is too low, and over 90% hoped for a future with more, or significantly more trees.

Respondents generally felt that there were too few trees across a range of land use types, but were most satisfied with the level of tree canopy cover on natural land and nature reserves, and the least satisfied with the level of cover on commercial, retail and industrial land.

There was general perception amongst respondents that there is some space, or even a lot of space, available for additional tree planting. The areas in which respondents perceived the smallest amount of available space were along roads and in residential gardens. The most available space was perceived to be in parks, on farmland and in nature reserves.

Many respondents have had some prior dealings with the Council in relation to trees. Typically this is around Tree Preservation Orders, tree maintenance, planning applications and reporting or querying incidents and works. There was a strong preference amongst respondents for communication with the Council via email and the website, whereas telephone calls, and written or app-based communication was not supported.

Particular issues and challenges for trees

Climate change is increasing extreme weather events such as drought and flooding and this impacts trees and woodlands. Extreme weather conditions may lead to a decline in health in the existing treescape and make it harder to establish newly planted trees. Higher temperatures, especially in urban locations, may mean that some commonly planted species are no longer suitable and greater consideration will need to be given to appropriate species selection.

Ensuring a tree population is resilient to the effects of climate change is important to ensure the ongoing health of the treescape and continuity of benefits it provides. Trees which are weakened by extreme weather conditions may be more susceptible to attack by pests and diseases, and novel pathogens are increasingly common because of changes in natural range, international trade and travel, and changes in climate.

Significant pests and diseases already affect the local tree population including Chalara ash dieback (Hymenoscyphus fraxineus), Dutch elm disease (Ophiostoma novo-ulmi) and bleeding canker of horse chestnut (Pseudomonas syringae pv aesculi).

A lack of species diversity makes tree populations less resilient to environmental and biological threats. Limitations in historic species selection and a large proportion of street trees belonging to the Rosaceous family mean they share susceptibility to some diseases, and a significant number have declined or failed.

Appropriate species selection is particularly important for new tree planting schemes across the city.

Selecting native species can have benefits for biodiversity. However, as the climate changes, some native species may no longer be appropriate for certain town centre locations and successful schemes will rely on the right trees being planted in the right place.

Understanding what constitutes the right tree relies on defining objectives including size, the constraints or threats in the location, and the purpose of planting.

The authority structure (county council, city council, and parish councils) presents particular challenges to the management of the tree population, which does not reflect or recognise administrative boundaries.

In simple terms, the authority structure means that the asset (the treescape) is fragmented into multiple jurisdictions, and the responsibilities and resources that are available to manage or improve it are also but differently fragmented. This creates the potential for duplication and inefficiency, and it introduces inertia to critical pathways that could otherwise be more streamlined.

Staff and skills, land ownership, public and political support, systems and tools, budgets, access to funding or revenue streams, policies, powers and procedures are spread between organisations and therefore not necessarily readily assembled to delivery services where this would require any particular blend.