Trees in cities provide numerous benefits; removing air pollution, improving the aesthetics, providing habitat for wildlife and even temperature control.
Ecosystem valuation attempts to assign a financial figure to the services provided by ecosystems. In a monetary society value is generally measured in economic terms. A plot of land may be considered purely in terms of rentable or saleable value for example. However that plot of land may contain natural features that provide other benefits not easily measured in economic terms, such as surface water attenuation that prevents flooding of developed areas downstream. By developing a systematic, consistent approach to assigning a financial value to the benefits an ecosystem provides then the hope is that this will be more easily factored into decision making.
The contractor helped to fund a survey of the trees in Kennington Park, central London, by the charity Trees for Cities to understand the variety of species present and to try and put a monetary value on the ecosystem services that these trees provide. The survey utilised a software application called i-tree eco, which enables monitoring data including air quality and meteorological conditions to be uploaded and quantifies the effects/benefits of trees.
The trees were valued at £12.3 million and consisted of 480 trees of 75 different species. Annual ecosystem services were valued at £13,300. This includes 307 kg of air pollution removed each year, 8 tonnes of carbon removed from the atmosphere and 528,200 litres of runoff water avoided.
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