Some thought that Stefano Boeri Architects' Bosco Verticale – a pair of skyscrapers clad in large amounts of greenery – was an idea best left on the drawing board. However, its completion and critical acclaim led to a successor being designed in Switzerland, and now a third "Vertical Forest" is planned for Nanjing, China.

While Boeri certainly wasn't the first architect to think of putting greenery on a skyscraper, a significant amount of the credit (or, if you prefer, blame) for greenery-clad towers being in vogue at the moment can be placed at his feet because of the popularity of Bosco Verticale.

The Nanjing Vertical Forest follows a very similar design language to that project and consists of a pair of towers atop a shared podium. They will reach a height of 200 m (656 ft) and 108 m (354 ft) respectively, and include office space, a hotel, a green architecture school, retail space, restaurants, a conference hall, and exhibition spaces. The taller tower will feature a private club on its rooftop and the smaller one a swimming pool.

In total, the buildings will sport 600 tall trees and 500 medium-sized trees (sourced from 23 local species), plus 2,500 cascading plants and shrubs in concrete planters integrated into balconies.

According to the firm, all this greenery will absorb some 25 tons of CO2 per year, while producing about 60 kg (132 lb) of oxygen a day.

Of course, just planting all those trees and shrubs in the ground around the towers would probably be better for the environment given the amount of extra concrete required to house them safely on the towers, so it's probably best not to get too carried away with claims of sustainability. Still, in allowing each resident their own miniature garden of sorts and improving their quality of life, the idea clearly has merit.

The Nanjing Vertical Forest was commissioned by Nanjing Yang Zi State-Owned Investment Group and is expected to be completed in 2018. Boeri hopes to refine his idea further with more Vertical Forest projects around the world, including in Shijiazhuang, Liuzhou, Guizhou, Shanghai and Chongqing in China.

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