London Is Drawing a 200 Kilometre Ring of Trees Around the City

CPRE's 25-year Tree Ring launches on 15 October, with ten sites already planted

CPRE London is about to launch the London Tree Ring, a plan to thread a 200 kilometre green corridor along the outer borough boundaries of the capital. Organisers call it an M25 for nature. The official launch is 15 October 2026. The idea has been in research since 2023. It is a 25-year project, not a weekend plant-a-tree drive.

The point is to reconnect woodland and hedgerow that have been cut into pockets, to hold greenbelt against being nibbled away, and to cool a city of about 10 million people on a typical day. Ten demonstrator sites were planted in the 2025/26 season. On the south-west edge, the project worked with a countryside skills provider to revive hedgerows with 1,500 trees, including disease-resistant elm — a species London mostly lost.

Schools, landowners and skills providers are being asked to find the next sites and to maintain them. A ring on a map does nothing if the saplings die in a dry July. The organisers are explicit that people, not a contractor's before-and-after photo, are the maintenance plan.

Key Facts

• Launch: 15 October 2026
• Length: 200 kilometres, about 124 miles
• Horizon: 25 years
• Demonstrator sites planted in 2025/26: 10
• One site: 1,500 trees, including disease-resistant elm
• People in London on a typical day: about 10 million
• Sources: Positive News, CPRE London

Why This Matters

Cities do not overheat evenly, and they do not lose nature evenly. A corridor on the outer edge is where greenbelt, commuting towns and leftover woods actually meet. Twenty-five years is an honest timeline. Most urban greening announcements are not.

What We Don't Know Yet

• The ring is not planted. Ten sites are
• Long-term watering, vandalism and landowner dropout are the real risks
• No independent audit yet of survival rates on the demonstrator sites

Sources

• Positive News
• CPRE London