Managing urban trees
Trees are an essential part of our towns and cities. We must plan for their long term management.
Street trees bring wildlife into urban areas and provide habitat and food for birds and insects. They are very important at the city and neighbourhood scales for moderating temperatures through the shade that they provide. Trees can be used to optimise (and avoid excessive) solar gain to buildings, especially when planted by south-facing areas. Deciduous trees will be in leaf and provide shading during hot summer months (reducing the need for mechanical cooling) but will lose their leaves in winter and allow solar gain to the building (reducing the need for heating).
To obtaining the maximum, long-lasting benefit from managing urban trees it is essential to involve a broad range of people, including communities, developers, highways engineers, local authority planners, parks managers, arboriculturalists, landscape architects and ecologists. An example of multiple interests coming together is the Trees and Design Action Group, which brings together a diverse range of people to protect and plant more large trees in urban areas. They have produced guidance called No Trees No Future.
Several community forestry initiatives demonstrate the value of involving the community in design, species selection and maintenance of trees planted locally. The Green Streets projects of Red Rose Forest (in Greater Manchester) and Mersey Forest are planting street trees in areas of socio-economic deprivation where there is currently little green cover. Local communities are involved in the process from the outset through to watering trees once they have been planted and this helps give a sense of community ‘ownership’ of the trees. The charity Trees for Cities promotes community involvement in tree planting.
Trees in Towns II highlights a need for more consistent standards of tree management at a city scale. To encourage this, it recommends ten targets that all English local authorities could try to achieve within the next five years:
- Have at least one specialist tree officer
- Obtain at least £15,000 in external funding for the tree programme over the next five years
- Develop and implement a comprehensive tree strategy
- Undertake a best value review of the tree programme
- Install a computerised tree management system
- Ensure that at least 40% of tree maintenance work is done on a systematic, regularly scheduled cycle
- Ensure that at least 90% of newly planted trees, excluding woodland plantings, receive systematic post-planting maintenance until they are established
- Ensure every tree preservation order is reviewed on a specified cycle
- Develop comprehensive trees and development Supplementary Planning Guidance
- Monitor every consent to work on protected trees and take enforcement action where necessary.
To protect and plant new trees in streets will need considerable investment in soil moisture balancing, root protection and building foundation design to reassure building owners about the impact of trees on soil heave and subsidence in shrinkable clay areas. Mature trees should be protected to prevent unnecessary removal and damage to roots from activities such as the laying of cables. More information on managing and designing for large trees in urban areas can be found in No Trees No Future.
CABE and Urban Practitioners
with the cities of Birmingham, Bristol, Leeds, Liverpool, Manchester, Newcastle, Nottingham and Sheffield