Managing urban trees

Trees should be seen and promoted as a key part of streetscape design and it is essential that their long-term management is taken into consideration.

Aboriculturist. Photo by Capel Manor College 2009.

Street trees provide an opportunity to bring wildlife into the urban form and provide habitat and food for a range of birds and insects. They are also very important at the city and neighbourhood scales for moderating temperatures within the public realm through the shade that they provide.

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.

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

Providing trees at a neighbourhood and site scale streets will need considerable investment in soil moisture balancing and root protection and building foundation design to reassure building owners about the impact of trees on soil heave and subsidence in shrinkable clay areas. Protection should also be given to mature trees to prevent unnecessary removal and damage to roots from activities such as the laying of cables.

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).

Priority: integrate green infrastructure into urban areas
Tags: green infrastructure, public space, neighbourhoods