Inside China’s plan to bury a smog-choked city in 40,000 trees

Liuzhou, a city of roughly 1.5 million people in China’s mountainous Guangxi region, has struggled with heavy smog from rapid industrial growth, and the usual toolkit of stricter emissions rules, factory shutdowns and better public transport has only chipped away at the problem. So Italian architecture firm Stefano Boeri Architetti went further, designing an entire neighbourhood meant to work like a forest.

Liuzhou Forest City covers about 175 hectares on the northern edge of the city, running along the Liujiang river. Once built, it is expected to include around 40,000 trees and close to a million plants spread across more than 100 species, covering the rooftops, balconies and facades of offices, homes, hotels, schools and even a hospital. The masterplan was commissioned by the Liuzhou Municipality Urban Planning Bureau.

The idea traces back to a much smaller project: Bosco Verticale, or ‘Vertical Forest’, a pair of residential towers Boeri built in Milan that were completed in 2014. According to Stefano Boeri Architetti’s own project page, those two towers alone filter around 15 to 17.5 tons of soot out of the air every year, a result that convinced Boeri the same principle could work at the scale of an entire city.

Figures shared by the firm suggest the vegetation planned for Liuzhou could absorb close to 10,000 tons of carbon dioxide and around 57 tons of fine particulate pollutants a year, while producing roughly 900 tons of oxygen annually. The greenery is also designed to cut the urban heat island effect, reduce traffic noise and create habitat for birds, insects and small animals.

Energy self-sufficiency is built into the plan too, with geothermal energy handling heating and cooling and rooftop solar panels generating electricity, alongside a dedicated rail line reserved for electric vehicles connecting the neighbourhood to the rest of Liuzhou.

Stefano Boeri Architetti has floated similar forest-city concepts for other heavily polluted Chinese cities, including Shijiazhuang, and has already completed standalone vertical-forest towers in Nanjing on a smaller scale. With China adding tens of millions of new city dwellers every year, Boeri has described the project as an attempt to prove that dense urban living and real biodiversity do not have to work against each other.