Pretty green

With over 5,000 shrubs, 11,000 floral plants and 900 trees on a 8,900 m2 surface, the towers have become a biological habitat that now hosts the nests of more than 20 species of birds. Also many different insect populations live in the Vertical Forest. Together, the two towers contain as much greenery as one third of the surface of the Biblioteca degli Alberi, the park next to the towers.

The vast amount of green also helps absorb CO2 and dust particles, reduce heat-island effects, mitigate noise pollution and save energy within the apartments. Together with the development of new parks and towers, the project also helped to revitalise an area that was once dominated by unused railroad tracks and decaying industrial buildings.

How does a vertical forest work?

The greenery is housed on the balconies of the apartment towers. The soil contains a mix of agricultural soil, organic matter and volcanic material, which is much lighter than the soil usually used in gardens and balconies. A central irrigation system is used to water the greenery. About 8 km of water pipe runs across the two buildings, through which the groundwater is distributed. The plants and trees are also equipped with a sensor that indicates when they need to be watered.

Maintenance of the greenery is not done by the residents of the towers but by the ‘‘flying gardeners’’. Massimo, Giovanni and Gilberto, who are expert climbers and botanists, have earned this nickname as they abseil from the roof of Bosco Verticale every 3-4 months to trim and prune the shrubs and trees floor by floor. You can see them in action in this documentary.

Sources:

• NPO

• Arup

• Architectural Digest

• Time to Momo

• Iaas

• Stefano Boeri Architetti