Visions of the urban future tend to revolve around mile-high skyscrapers, flying cars and high-tech solutions to sustainability challenges.
But there is another vision that foresees a return to the wilderness that cities were once built upon, complete with forests and wild animals that were lost long ago. That vision is beginning to be realized in major cities around the world in the shape of the urban rewilding movement.
Botanist Akira Miyawaki is among the forefathers of this nascent effort, having made an important discovery while researching Japanese vegetation in the 1970s. He noticed that ancient, indigenous forest ecosystems were surviving and thriving on untended land such as temples and cemeteries, whereas they had long vanished from cultivated plots.
Miyawaki set about a program of restoring Japan’s natural forestry at small sites across the country, using indigenous soil and plants. In many cases the results were spectacular: rapid growth of dense and diverse ecosystems.
The “Miyawaki method” has since become a global movement, with miniature forests guided by the botanist’s principles flourishing across the US, Europe, and Asia. They are also taking root in urban environments from Beirut to Bordeaux, and playing a leading role in a movement to bring wild nature to the heart of cities.
One of the largest Miyawaki projects is led by the not-for-profit Institute for Environmental Education (IVN) in the Netherlands. Its Tiny Forest scheme has established more than 250 plots around the size of tennis courts in urban locations such as roadsides, business parks and schools.
“First of all, it starts with site selection and trying to see what type of soil we are dealing with, what is the water level, what is the potential natural vegetation on the site,” says Daan Bleichrodt, chief tree planting officer at IVN. “You can do that by looking into the past to see what used to grow.”
There is minimal interference once the plants and trees have been seeded. Over time ecosystems develop that take on lives of their own. One study of 11 forests found more than 600 animal species and almost 300 plant species “that showed up in the forests by themselves,” says Bleichrodt.
The forests serve as small carbon sinks, each capturing an average of 127.5 kilograms of CO2 per year, according to the same study – equivalent to the emissions from an average car driving more than 300 miles – which could double as the forest matures.
They also provide a cooling effect. Researchers found soil temperatures were up to 20 degrees Celsius lower than on nearby streets.
Resilience to climate change
The concept of rewilding – broadly the restoration of indigenous, natural ecosystems and processes – has blossomed in rural areas, from reintroducing wolves to Yellowstone Park to old-growth forestry in the Carpathian Mountains. Environmentalists believe the same principles can be applied to urban spaces.
Urban rewilding is an “approach that aims to increase ecological complexity in urban ecosystems with minimal to no management intervention in the long term,” says Nathalie Pettorelli, senior scientist of the Zoological Society of London (ZSL) and lead author of its recent report Rewilding Our Cities.
The report sets out a suite of possibilities for interventions, from allowing wildlife to reclaim golf courses and develop around railway infrastructure, to boosting private vegetation and ending the management of parks to allow natural processes free rein. Measures “could also include active replanting and targeted species recovery efforts.”
Potential benefits of restoring urban ecosystems could include strengthening resilience to climate change, reducing pollution, reversal of biodiversity loss, and healthier resident populations, says Pettorelli.
Urban rewilding is a “relatively new” movement, she says, pointing to a handful of cities taking bold steps in this direction. Singapore has installed “Supertrees” and green corridors that accommodate wild ecosystems, while three German cities are participating in a scheme to allocate spaces for wild habitats to grow freely.
A radical proposal for the regeneration of English city Nottingham would have seen a rundown shopping mall in the center transformed into an urban oasis surrounded by woodland and wild meadows. The local council is pressing ahead with an adapted vision, with acclaimed designer Thomas Heatherwick, for the city to be reoriented around a vast “green heart” that will allow the mall to be overgrown with flora.
Avoiding “green gentrification”
London is also taking ambitious steps through the mayor’s London Rewilding Task Force, which is supporting dozens of separate but complementary schemes. Local authorities and activists have reintroduced beavers to the city for the first time in centuries, developed new woodlands, and created habitats for butterflies.
The next phase could include the conversion of managed grasslands to wild meadows, miles of green highways for the benefit of bees, butterflies, and wildflowers, and the reintroduction of large grazing animal herds to shape the ecosystems of outer London. But the vision is bottom up as well as top down.
“As well as large-scale (projects) which need large spaces, we also want to drive more smaller-scale actions across London on people’s doorsteps,” says Shirley Rodrigues, Deputy Mayor for the Environment. These include initiatives to record wildlife levels in local neighborhoods and identify species whose conservation should be prioritized.
Such plans are not an indulgence but make sense for a global city to pursue on multiple levels, says Rodrigues. “We know that rewilding can restore ecosystems and grow the range and abundance of different species in an area, but it also has a much wider-reaching role in making cities greener, healthier and more resilient to the impacts of climate change, as well as improving the health and wellbeing of Londoners,” she says.
The ZSL identified recurrent challenges facing urban rewilding projects. Larger initiatives will require public funding that is scarce in straitened times. Leaving wild plots untended risks invasive species being introduced and negatively impacting ecosystems.
Projects must have buy-in from local people to thrive, and avoid “green gentrification” that displaces people from targeted areas. Harmful practices such as the use of pesticides and artificial lawns must be tackled to give rewilding a chance. “We need stronger legislation to counteract the spread of activities that undermine efforts to restore urban nature,” says Pettorelli.
But the movement is gathering momentum. Bleichrodt lists complementary schemes that work alongside the Tiny Forest project such as greening initiatives in schools, growing food in public spaces, and new experiments in sustainable water management. Tiny Forest has established a network across 10 countries from Curacao to Pakistan and is focusing on building awareness of new generations by working closely with local schools.
“I feel like part of a bigger movement that’s trying to restore ecosystems,” says Bleichrodt. “A rewilding regeneration movement.”