Architect Stefano Boeri has always been obsessed with trees. The Italian traces his fascination back to a novel he read as a child, “Il Barone Rampante” (“The Baron in the Trees”), in which a young boy climbs up into a world of trees and vows to never to return.
“I think trees are individuals,” Boeri said in a phone interview. “Each has its own evolution, its own biography, its own shape.”
Unsurprisingly, there is child-like wonder to the architect’s best-known building, Il Bosco Verticale, or the Vertical Forest. Built in his home city of Milan, the celebrated complex teems with greenery, its facades transformed into living, breathing organisms.
The project’s two residential towers – measuring 80 meters (262 feet) and 112 meters (367 feet) respectively – play host to around 20,000 trees, shrubs and plants. They spill out from irregularly placed balconies and crawl up the structures’ sides. By Boeri’s estimates, there are two trees, eight shrubs, and 40 plants for each human inhabitant.
The purported benefits of this garden architecture transcend aesthetics. Greenery, supposedly, provides shade to apartments, psychological benefits to residents and a home to wildlife. (There are, Boeri said, “hundreds of birds, more than 15 different species” nesting on the towers’ various floors.)
But the architect’s proudest claim is that the buildings absorb 30 tons of carbon dioxide and produce 19 tons of oxygen a year, according to his research, with a volume of trees equivalent to more than 215,000 square feet of forestland.
“The ability to enlarge green surfaces inside and around our city is one of the most efficient ways to try to reverse climate change,” he said. “So, a vertical forest is one of the possible ways to … enlarge biological surfaces, in the horizontal and the vertical. (The solution is) not only gardens. Why not also the side of the building?”
Other energy-efficient features, including geothermal heating systems and wastewater facilities, have attracted less attention. Nonetheless, they help the towers to not only resemble trees, but function like them too, the architect said.
“The buildings really work as trees, from the roots up,” he explained. “They have a trunk, and they distribute (water and energy) through the different branches.”
Scalable urban model
In September 2018, Vertical Forest was named among four finalists for the RIBA International Prize, a biennial award honoring the world’s best new buildings. Despite the plaudits, Boeri claims the project’s real success is that it serves as a prototype.
The architect has far more ambitious designs. His firm has already unveiled plans for new Vertical Forest buildings in European cities including Treviso in Italy, Lausanne in Switzerland and Utrecht in the Netherlands.
In the Chinese city of Liuzhou, Guangxi province, he has masterminded an entire “Forest City,” scheduled for completion in 2020, which comprises tree-covered houses, hospitals, schools and office blocks over a sprawling 15-million-square-foot site. (Boeri said that he’s also been approached about producing similar “cities” in Egypt and Mexico.)
Each location requires detailed research to decipher which species of plants and trees will flourish. (Levels of humidity, wind and sunlight are the most challenging variables.) Before opening h