Most people appreciate the beauty of London's trees but may not know, or tend to take for granted, the benefits that London's urban forest provides for both people and nature. The i-Tree report, sponsored by Unilever, gives us a much better understanding of the structure and value of London's urban forest. It is a method that is recognised worldwide and enables comparison with other cities. The information produced enables us to make better plans to manage London's trees and highlights the need for continued tree planting to increase tree canopy cover over London.
The survey found that:
• Each year London's trees remove 2241 tonnes of pollution worth £126m per year. Air pollution is a major issue for London and the contribution made by trees to its reduction has a direct positive impact on public health and is – literally - life saving.
• Each year London's trees intercept rainfall and prevent nearly 3½ million cubic metres of water from entering the drainage system and so, reducing the risk of flooding and water pollution events. This is the equivalent of 1365 Olympic swimming pools with a monetary value of £2.8m per year.
• London's trees store 2.4 million tonnes of carbon and they sequester carbon dioxide from the atmosphere to reduce the impact of climate change. This is equivalent to the carbon produced from 26 billion vehicle miles.
The report highlights that there are a wide range of tree species - not just native trees but trees from around the world - that are suited to London conditions. However, at a more local level there are vulnerable landscapes that are currently reliant on one or two tree species, such as some parts of central London dominated by the iconic London plane. In order to reduce the risk of large numbers of trees being lost within a short time, planting of a wider species range is needed.
The report calls for everyone to recognise and support the multiple benefits that trees provide for London and to make their own contribution to protecting and enhancing London's tree cover. This will help ensure that London continues to be a green city for future generations by planting trees in gardens, supporting tree planting by others, supporting organisations that promote and protect London's trees.
Environment Minister, Rory Stewart, said: "Our trees and forests have long been central to British identity. But we are beginning to understand with even more precision, just how important they are to our air quality, our health and our happiness. This is a fantastic initiative. And it sits very well alongside our drive to plant an additional 11 million trees in this parliament, and to support green spaces across the country."
Charlotte Carroll, Unilever UK Sustainability and Communications Director, commented: "The findings of this report provide clear evidence of the importance of trees in the fight against climate change and of their value to our society in helping to deliver a more sustainable future. At Unilever we're working on this important issue through our brightFuture movement and with the UN Climate Conference, COP21 in progress, now is the time to engage in the importance of trees in our everyday lives."
The Mayor of London, Boris Johnson said: "London is one of the greenest, leafiest cities on the planet and as this survey proves, our canopy does a 'tree mendous' job of lowering pollution, alleviating flood water and boosting our environment."
Craig Harrison, Forestry Commission London Manager said: "The i-Tree report shows some of the ways in which London's trees enhance our daily lives, and many of the trees we enjoy today are the legacy of past tree planting. But London's trees face challenges such as development pressures, climate change and disease. With the expected increase in London's population the need for more trees will increase - so we need to protect existing trees and plant new trees - to ensure London remains an enjoyable place to live, work and visit."
London iTree Project
Urban Tree Project