An environmental charity is aiming to encircle the UK’s capital in an “M25 of nature”.
In an attempt to improve London’s biodiversity, environmental charity CPRE London is aiming to surround the city with an unbroken ring of trees.
The UK is among the most nature-depleted countries in the world, having lost half of its natural biodiversity since the 17th century. CPRE London hopes that encircling the city in greenery will benefit London’s biodiversity and the mental and physical health of its citizens.
The problem – the UK has lost half of its natural biodiversity

A 2021 study conducted by scientists at the Natural History Museum in London revealed that the UK has lost half of its natural biodiversity since the Industrial Revolution in the late 18th and early 19th centuries.
The museum’s Professor Andy Purvis commented that “Britain has lost more of its natural biodiversity than almost anywhere else in western Europe, the most of all the G7 nations, and more than many other nations such as China”.
Senior researcher Dr Adriana De Palma added that the UK was “consistently in the bottom ten per cent of nations in terms of biodiversity intactness”.
Purvis pointed the finger at the insatiable expansion of agriculture and technology during the Industrial Revolution that “triggered the mechanised destruction of nature in order to convert it into goods for profit”, leaving the UK “among the most nature-depleted countries in the world”.
The project – encircling London in trees

The project is the brainchild of environmental charity CPRE London and aims to join existing green belt areas in London’s outer boroughs to create a continuous ring of trees – an “M25 of nature”, as the charity dubs it, alluding to the motorway that surrounds the city.
CPRE London recognises that some areas may be inhospitable to traditional native woodland, so this “M25 of nature” will also include orchards, hedgerows, and, of course, street trees.
However, woodland remains the priority. CPRE director Anna Taylor commented, “Woodland is one of the most diverse habitats once it becomes established – a mature oak tree on its own can host 2,300 species”.
Mapping has begun in cooperation with community interest company Greenspace Information for Greater London. The first phase will focus on north London and the areas around Hainault and Epping forests.
The benefits of the “M25 of nature” – good for the environment, good for Londoners

While the positive impact on London’s biodiversity is self-evident, CPRE London’s project will also greatly benefit the city’s residents. Access to green spaces is beneficial for our mental well-being and could even reduce the need for certain medications.
The Woodland Trust’s Bridget Fox stressed the benefits for local communities: “We’ve known for decades how important woodland is for biodiversity. But something that was heightened during lockdown is how important having access to green space is for people’s well-being.
“Whether it’s the cleaner, moister, cooler air, or just the tranquillity of being in touch with nature […] having countryside on London’s doorstep, giving everyone better access to nature, is really important”.
Taylor also recognises the impact on the city’s residents, suggesting that the inclusion of Londoners is vital to the project and that the goal is “a community forest all about multi-purpose planting that really serves communities, rather than blanket planting of trees”.