Milan’s Vertical Forest

Visitors to Milan should definitely set aside a little time to see the Vertical Forest, the pair of famous residential towers designed by Stefano Boeri completed in 2014. Even when under construction, these skyscrapers instantly became famous as some of the world’s most innovative buildings. When work was completed, the public was awestruck by the towers’ dramatic appearance, covered with trees and coloured shrubs. To cap it all off, the leaves of Milan’s Vertical Forest change colour with the passing seasons. The buildings are in the Isola district, a part of Milan that has been completely renovated in recent years, particularly in the area immediately behind the famous Gae Aulenti piazza.

Stefano Boeri, architect of the Vertical Forest

Born in 1956, Stefano Boeri, the architect who runs the firm responsible for designing Milan’s Vertical Forest, has been one of world’s most famous architects for a long time. His fame has undoubtedly been boosted by the Vertical Forest. Indeed, the firm has been commissioned to build vertical forests in other cities: the Tower of Cedars in Lausanne, a Vertical Forest in Nanjing, a Vertical Forest in Utrecht, and the future Forêt Blanche in Paris to name but a few. Alongside his work as an architect, Stefano Boeri is also a well-known urban planner, urban designer and academic. Other Boeri buildings in Milan include the New RCS office building in Crescenzago, the Incubator for Art at Porta Nuova, an extension for the Policlinico, as well as the concept for the Expo 2015 site, for which he created the masterplan.

The concept behind the Milan Vertical Forest

Milan’s Vertical Forest may be considered a prototype for a brand new type of biodiversity-inspired architecture, in which design is no longer solely human-centric, but rather we are joined by other living species, that is to say plants, birds and so on. The Vertical Forest is first and foremost a home for trees that also happens to be a home for humans and birds. Structurally, the two buildings sport large, staggered balconies with three metre-wide overhangs. These accentuated protrusions offer a home for vegetation, planted in special tubs so that they may grow without let or hindrance. The Vertical Forest’s tallest trees are up to three storeys high. The facade is not a surface but a three-dimensional space finished in porcelain stoneware that elegantly mirrors the brown of the tree trunks. The end result is that the two towers look very much like two tall tree houses.

The construction of Boeri’s Towers

The Isola district has been undergoing major regeneration since 2005. Stefano Boeri first came up with the idea of building a plant-covered skyscraper on a trip to Dubai, when he grew weary of cities made of steel, glass and ceramics. His idea appealed to Hines, the multinational real estate company in charge of overseeing the Porta Nuova Scheme, which included a renewal of the Isola district. Construction work began in 2009, initially employing some 6,000 workers. South Tyrolean company ZH won the commission to carry out the work, but construction soon fell behind schedule as the company underwent a financial crisis. ZH had to withdraw from the project four years later, in April 2013. The job was immediately awarded to Colombo Construction, which delivered the two towers in the fall of 2014.

It is of course impossible to talk about construction of Milan’s Vertical Forest without mentioning how the plants that adorn it and make it so exceptional were grown. They were, in fact, pre-cultivated in a botanical nursery from 2010 onwards, and only distributed on the towers in their final configuration after a three-year-long period of functional and aesthetic research.

The Milan Vertical Forest in numbers

The Milan Vertical Forest’s two towers are of different heights: one soars 112 metres above ground, the other 80 metres. The two skyscrapers house a total of 800 trees, as well as approximately 15,000 perennials and ground cover plants, and 5,000 shrubs. Concentrated in just 3,000 m2 of city, the towers feature as much vegetation as is normally found on around 30,000 m2 of forest and undergrowth. The plants in the Vertical Forest filter the sun’s rays to create an optimal microclimate; they also regulate humidity, carbon dioxide/fine particle absorption, and produce oxygen. The vertical forest has become a habitat for a number of animal species, not least 1,600 birds and butterflies.

The towers’ financial numbers are equally impressive: it cost €40 million to build the Vertical Forest. Initially, apartments went on sale at €7,000 per m2; today, they fetch over €15,000 per m2, particularly the highest floors – a rise in value explicable by the many awards and accolades the Vertical Forest has won since it was completed.

Another major cost item is the not insignificant maintenance fee needed to keep the vertical forest in good health. This ecosystem requires 24/7 oversight by staff, hence the standard condominium fee for each housing unit of around €1,500 per month.

Awards the Milan Vertical Forest has won

The scheme has won a host of different awards, the most prestigious being the International Highrise Award from the Deutschen Architekturmuseums in Frankfurt (2014), and the CTBUH Award for the world’s best tall building from the Council on Tall Buildings and Urban Habitat at IIT Chicago (2015).