Cities need those old trees

At a time when cities are committing hara-kiri and cutting down trees to widen roads, here is something to think over.

Vegetation in towns and cities can make a significant contribution to carbon storage and, ecologists say, could lock away even more carbon if local authorities and gardeners planted and maintained more trees. The study was published week in the British Ecological Society's Journal of Applied Ecology.

Using satellite data and information gathered by visiting local parks and gardens, the researchers surveyed vegetation across Leicester, including domestic gardens and council-owned parks, golf courses, abandoned industrial land, road verges and river banks.

They found 231,000 tonnes of carbon (C) locked up in Leicester's above-ground vegetation, equivalent to 3.16 kg C per square metre of the city, an order of magnitude greater than current national estimates. Most of this carbon pool is associated with trees.

Large trees are especially important carbon stores, said the team leader. Trees, particularly large ones, should be protected and maintained and if more trees are planted in urban areas for their carbon storage value, they must be the right kind of tree planted in the right place so that they have a long, productive life span, and when trees die they should be replaced.

Are our city planners listening?