- Trees and woodlands should be protected, and new trees and woodlands should be planted in appropriate locations in order to increase the extent of London’s urban forest – the area of London under the canopy of trees.
- In their Development Plans, boroughs should:
- protect ‘veteran’ trees and ancient woodland where these are not already part of a protected site
- identify opportunities for tree planting in strategic locations.
- Development proposals should ensure that, wherever possible, existing trees of quality are retained. If it is imperative that trees have to be removed, there should be adequate replacement based on the existing value of the benefits of the trees removed, determined by, for example, i-tree or CAVAT. The planting of additional trees should generally be included in new developments – particularly large-canopied species which provide a wider range of benefits because of the larger surface area of their canopy.
 Category A and B trees as defined by BS 5837:2012
Trees and woodlands play an important role within the urban environment. They help to trap air pollutants, provide shading, absorb rainwater and filter noise. They also provide extensive areas of habitat for wildlife, especially mature trees. The urban forest is an important element of London’s green infrastructure and comprises all the trees in the urban realm, in both public and private spaces, along linear routes and waterways, and in amenity areas. The Mayor and Forestry Commission, have produced Supplementary Planning Guidance on preparing tree strategies to help boroughs plan for the management of the urban forest. These should be part of boroughs’ wider green infrastructure strategies.
The Mayor wants to increase tree cover in London by 10 per cent by 2050. Trees should be designed into developments from the outset to maximise tree planting opportunities and optimise establishment and vigorous growth. When preparing more detailed planning guidance boroughs are also advised to refer to Right Trees for a Changing Climate and guidance produced by the Trees and Design Action Group, a multi-disciplinary cross-partnership forum seeking to promote urban forests.
An i-Tree Eco Assessment of London’s trees quantified the benefits and services provided by the capital’s urban forest. This demonstrated that London’s existing trees and woodlands provide services (such as pollution removal, carbon storage, and storm water attenuation) valued at £133 million per year. The cost of replacing these services if the urban forest was lost was calculated at £6.12 billion. Consequently, when trees are removed the asset is degraded and the compensation required in terms of substitute planting to replace services lost should be based on a recognised tree valuation method such as CAVAT or i-Tree Eco.