London to plant 2m trees by 2025, says mayor's office

Mayor's adviser announces plans to make London 'greener, cleaner and more civilised' with 2m tree plan
Press Association
guardian.co.uk, Thursday 30 July 2009 11.41 BST
London needs more parkland and to plant more trees to combat predicted rises in summer temperatures, an environment chief said today.
Mayor Boris Johnson's environment adviser Isabel Dedring said climate projections showed average summer temperatures in London could be some 3.9C higher than today by 2080, and as much as 6C to 10C on the hottest days.
The "urban heat island effect" in which buildings absorb and release heat, maintaining a higher temperature in cities than surrounding areas, means London temperatures will continue to be higher than other parts of the south-east.
But a study from Manchester suggests that increasing the amount of greenery in a city by 10% could offset the higher temperatures.
The mayor's environment plan is aiming to increase tree cover across the capital by 5% – an extra 2m trees – by 2025.
The programme, Leading to a Greener London, also involves plans for an increase in green space in inner London by 5%, including green roofs and more trees in streets. A green roof features waterproofing and drainage layers topped with soil and plants.
Other measures to make the capital "greener, cleaner and more civilised" include pilot schemes which will pay householders to recycle.
"Trees in streets have a very positive air-quality effect," Dedring added.