Policy BG/TC: Improving Tree Canopy Cover and the Tree Population

DRAFT version for various committee meetings.

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What will this policy do?

This policy will control how development impacts tree canopy cover, the tree population, and protected trees and hedgerows.

Proposed policy direction

The policy will require development proposals to: 

  • preserve, protect and increase the amount and distribution of tree canopy cover. 

  • Protect and enhance the tree population on site, including its diversity and distribution. 

  • protect existing trees of value (including landscape, heritage, cultural, amenity, biodiversity, ecosystem service or aesthetic value) as measured by a recognised tool such as iTree

  • protect existing hedgerows and the surrounding land that supports them, and to plant new ones where appropriate 

  • provide sufficient space above and below ground for trees and other vegetation to mature.         

  • provide appropriate replacement tree or hedgerow planting, where felling is proved necessary. 

The policy will also encourage the provision of new woodland of locally appropriate species in appropriate locations.

Why is this policy needed?

National planning policy and guidance recognises the many benefits provided by trees, including encouraging walking and enhanced physical and mental health; contributing to local environmental character and distinctiveness; providing habitats for wildlife; supporting sustainable drainage; mitigating climate change by storing carbon dioxide; and reducing noise and excessive heat in urban areas. Further to this, proposed changes to the National Planning Policy Framework will see authorities required to make new streets tree-lined. Government has also recently launched the England Trees Action Plan 2021-24. At an OxCam Arc level we have signed up to the aim of increasing tree and woodland cover across the Arc from 7.4% to 19%. 

Tree canopy cover is the name given to the layer of leaves and branches that cover the ground. It is measured as a percentage of the total area. Large-canopied tree species provide a wider range of benefits because of the larger surface area of their canopy. Which is why supporting an increase in canopy cover rather than just an increase in the number of trees is a priority. 

The tree population or treescape includes the variety of species, ages and distribution of trees within an area. The greater the variety and distribution, the greater the biodiversity value and resilience of the tree population. 

Locally, low tree and tree canopy cover is recognised as a weakness within the ecological network of Greater Cambridge, both in the rural agricultural areas typified by large open fields lacking boundary features, and in more urban areas which pre-date the current requirements for ecological enhancement above no net loss. To address these challenges, the Cambridge City Council Citywide Tree Strategy 2016-26 Canopy Cover Project seeks to support Cambridge City Council’s aim of achieving 19% tree cover by the 2050s; South Cambridgeshire also has identified a priority of increasing tree canopy cover in it is Doubling Nature Strategy.  

In response to the above context, this policy seeks to ensure that development proposals increase tree canopy cover, enhance treescape, and protect existing trees of value. Where tree retention or planting is proposed in conjunction with new developments, the objective should be to achieve a harmonious relationship between trees and structures that can be sustained in the long term. The constraints imposed by trees, both above and below ground should be considered at the outset as they will inform site layout.  

We recognise that in some instances felling of existing trees or hedgerows may be necessary to meet wider placemaking objectives. In such cases the policy will require replacement planting. 

Hedgerows are also important biodiversity, cultural and archaeological features in South Cambridgeshire in particular, noting our relative lack of tree canopy cover, and it is important to retain and protect both hedgerows themselves and the surrounding space which supports their flourishing (known as terroir).  

Groupings of trees in woodland multiply the benefits provided by individual trees. We want to encourage the provision of additional broad-leaved woodland in appropriate locations, which could be provided at a range of scales and in different contexts, including for example micro-woods, tree belts, orchards and woodland. 

What consultation have we done on this issue?

Feedback to the First Conversation consultation relevant to trees and hedgerows included comments supporting the protection of existing trees, noting their varied benefits, and also supporting the planting of new trees and woodlands in appropriate locations. Comments noted that a strategic approach should be taken to tree and hedgerow provision, noting that it is not just about the number of trees. Some comments raised the importance of balancing the priority for tree planting alongside other priorities such as the need for housing and employment, and also landscape impacts. 

What alternatives did we consider?

1. Rely on national policy - This alternative is not the preferred approach as it would not provide protection for trees of amenity or other value that are not part of ancient woodland or having Tree Protection Order status.

2. Set a specific requirement for tree canopy cover in new development.  - This alternative is not the preferred approach as high canopy cover requirements could mean that woodland would dominate a development site’s landscape and biodiversity provision, at the expense of a more biodiverse mix of habitats and landscapes.

Supporting evidence studies and topic papers

  • Greater Cambridge Green Infrastructure Opportunity Mapping Final Report (2021) 

Existing policies in adopted 2018 Local Plans

South Cambridgeshire Local Plan 2018 

  • Policy NH/7 Ancient Woodlands and Veteran Trees 

Cambridge Local Plan 2018 

  • Policy 71: Trees 

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