London is a forest – who knew? | Patrick Barkham

The i-Tree study could transform our cities by confirming the vital status of trees as green infrastructure

I strolled through a wood last week and didn't even realise it. According to a UN definition, London can be classified as a forest, its 8.4 million trees - almost one for every person - adorning and detoxifying this great city. I was on my way to a wood-panelled room in the House of Lords for the launch of a study calculating the value of London's trees using open-source software developed in America.

The i-Tree study, undertaken by volunteers, charities and government agencies including the Forestry Commission and Natural England, shines vivid light into the urban jungle. London may be renowned for the handsome plane trees that dominate its centre, but the capital's most common tree is actually the sycamore, followed by English oak and silver birch.