The last time Madrid was surrounded by forests was in the 1500s when thickets of mushroom-shaped holm oaks buffeted the not-yet Spanish capital. In the centuries since, many woodlands have given way first to farms and then the subdivisions and industrial zones of a modern metropolis. Madrid’s outward surge – its population doubled during one 20-year stretch last century – has fed erosion and driven away wildlife.

But Madrid could soon be ringed by forests again. The municipality has launched a drive to connect a series of existing woodlands, creating a 75km-long green belt around the city of 3.3 million, suburban escape officials call the Bosque Metropolitano or Metropolitan Forest. Once complete, the forest would cover 35,000ha. It would help the city improve its air quality, counter climate change and create a wealth of recreational opportunities for residents, says Silvia Villacañas from Madrid’s urban planning department.

“This past year, heavily shaped by the pandemic, has made us even more aware of our need for trees and the environment that surrounds us,” she said.

Madrid is one of several major cities, from Bangkok, Thailand to Medellin, Colombia, that are attempting to re-green themselves. The Madrid effort comes just ahead of the UN Decade on Ecosystem Restoration, a global push to revive natural spaces lost to development.

Urban areas are considered a key part of that drive. Home to 50 per cent of the world’s population, many have laboured as the natural spaces within and around them dwindle. By planting trees, bushes and other vegetation, cities can clean their air and water, limit heat waves and provide recreational opportunities for their residents, say experts.

That’s a model that Madrid is embracing. The green belt, which is about 80 per cent complete, will contain millions of trees, many of them native holm oaks, elms and willows. In 30 years, Villacañas says the forest will be able to absorb 500,000 tonnes of carbon dioxide annually. Walking and cycling trails will course through the forests, which officials say could be connected by “ecoducts”, ribbons of wilderness that run between factories and homes.

While only 20 per cent of the green belt is missing, completing the circle will involve regreening already developed land, which requires planning approvals and compensation for landowners.

“For us, this decade is going to be a crucial one in order to develop this great green infrastructure,” Villacañas said. “We will not have other possibilities to re-plan this (project). This is our last chance. “

The United Nations General Assembly has declared the years 2021 through 2030 the UN Decade on Ecosystem Restoration. Led by the United Nations Environment Programme and the Food and Agriculture Organization, the UN Decade is designed to prevent, halt and reverse the degradation of ecosystems worldwide. This global call to action will be launched on 5 June, World Environment Day. It will draw together political support, scientific research and financial muscle to scale up restoration with the goal of reviving millions of hectares of terrestrial and aquatic ecosystems. Explore UNEP’s work on preserving ecosystems, including forests, coastlines, peatlands and coral reefs. Find out more on the UN Decade of Restoration here.


Further resources :

Background: UNEP’s work in cities

Background: Restoring Urban Areas

Story: Cities and the fight for a green recovery