The Vertical Forest in Milan, Italy, designed by Boeri Studio (Stefano Boeri, Gianandrea Barreca and Giovanni La Varra) is the building prototype of a new architecture of biodiversity, which no longer focuses only on man, but on the relationship between man and other living species.
The use of concrete a construction material gave this building the ability to transform a neighbourhood and is a showcase of what can be achieved with such a dynamic material and some forward thinking.
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The first example built in the Porta Nuova area in Milan, consists of two towers 80m and 112m high, which house a total of 800 trees (480 first- and second-size trees, 300 smaller in size, 15 000 perennials and/or upholstery, and 5 000 shrubs. It is a vegetation equivalent to that of 30 000m² meters of forest and undergrowth, concentrated on 3 000m² of the urban area.
The project is thus also a device to limit the sprawl of the cities induced by the search for greenery (each tower is equivalent to about 50 000m² of single-family houses).
Vegetable screen of forest
Unlike the “mineral” facades in glass or stone, the vegetable screen of the forest does not reflect or amplify the sun’s rays, but filters them, generating a welcoming internal microclimate without harmful effects on the environment. At the same time, the green curtain “regulates” moisture, produces oxygen and absorbs CO₂ and fine dust.
The combination of these characteristics has earned the project important awards, including the International Highrise Award of the Deutschen Architekturmuseums in Frankfurt (2014) and the CTBUH Award as the best tall building in the world, of the Council for Tall Building and Urban Habitat of the IIT of Chicago (2015).
The concept of the Vertical Forest, which is being “a tree house that also houses humans and birds”, defines not only the urban and technological characteristics but also the architectural language and the expressive qualities of the project.
On the formal level, the towers are in fact characterised mainly by the large balconies staggered and with a strong three-metre cantilever, functional to accommodate the large perimeter tanks for vegetation and to allow the unhindered growth of larger trees, even along three floors of the building.
The porcelain stoneware finish of the facades takes up the brown colour typical of the bark, evoking the image of a pair of gigantic trees inhabiting, rich in literary and symbolic implications.
The contrast with a series of white stoneware elements – the string courses of the balconies and some modules on the front of the windowsills – introduces a syncopated rhythm in the composition, which breaks and “dematerialises” the visual compactness of the architectural bodies, amplifying even more the presence of plants.
More than as surfaces, facades can be observed as three-dimensional spaces – not only for the thickness and function of the green curtain but also on the aesthetic-temporal level, due to the cyclic polychromatic and morphological mutation in the volumes of plants.
Variations in colours and plant structures
In the various seasons, the variations in the colours and shapes of the plant structure generate a great iridescent landmark, strongly recognisable even at a distance – a characteristic that has generated in a few years the image of the Vertical Forest as a new symbol of Milan.
This principle of variation also acts in relation to the different treatments on the sides of the towers and on the various floors, where the choice and distribution of the essences reflect both aesthetic and functional criteria for adapting to the orientations and heights of the facades. The result of three years of studies conducted together with a group of botanists and ethologists, the development of the plant component preceded the same building life of the complex.
A few years after its construction, the Vertical Forest has given life to a habitat colonised by numerous species of animals (including about 1 600 specimens of birds and butterflies), establishing an outpost of spontaneous plant and faunal recolonisation of the city.
Click on the link to see the breath-taking Vertical Forest design: