London’s urban forest is increasingly recognised as having an economic value thanks to its environmental benefits. Trees give people a chance to be in direct contact with nature and attract woodland wildlife into even the most urban parts of the city.
The world’s largest survey of trees and woodlands is taking place in London. The survey will reveal for the first time the total tree cover in the capital and calculate the huge benefits they bring through boosting air quality, reducing flooding, and carbon storage.
The London iTree survey will see experienced foresters and arboriculturalists join hundreds of trained volunteers to measure trees in 725 plots across every borough. The survey teams will take detailed records of each tree in their plot, including stem diameter, tree height, size of tree canopy and condition of the tree. Other factors affecting the level of benefits that a tree can deliver will be recorded, such as land use and the amount of shrub and ground cover.
Matthew Pencharz, the Mayor of London’s Senior Advisor on Environment & Energy, said: “Whilst the beauty and intrinsic value of all the trees and woodland in London are recognised, most people are not aware of, or take for granted, the environmental benefits that they provide. This survey will highlight the immense value our trees bring to the our capital, and is part of our wider work to make London a greener city”
The survey will enable better planning of improvements to the number of trees in London and create a stronger understanding of their economic and environmental value. It will also help to deliver the Mayor’s target of increasing London’s canopy cover from 20 per cent to 25 per cent by 2025.
iTree software was originally developed by the US Forest Service to provide tools for analysing and assessing the benefits of urban trees. Free to use, it has since been used by local and national governments, other organisations and local communities around the world to strengthen their urban forest management and advocacy by quantifying the environmental services that trees provide.
The iTree methodology has been used on a smaller scale to demonstrate the value of trees in other parts of the UK, including a study in Torbay that found that the 818,000 trees there had a structural (or replacement) value of around £280 million, stored around 98,000 tonnes of carbon per year, and removed around 50 tonnes of particulate air pollution each year. The value and ecosystem services provided by London’s trees are expected to be far higher.
Hundreds of volunteers are helping carry out the surveys, including members of the Mayor’s Team London volunteering initiative. This is one of many green projects Team London are involved with including the Wide Horizons which is helping to transform a five-acre area in South London into a well-managed woodland.
The iTree survey is being co-ordinated by the Forestry Commission with support from the Mayor of London and the London Tree Officers’ Association. The survey concludes at the end of October and the results will be published in Spring 2015.