The urban vertical forest is one of the most intriguing ideas in contemporary architecture. The world’s first forested skyscraper is now nearing completion in the Italian design capital of Milan, reports Jeanne-Marie Cilento. Photographs by Marco Garofalo & Francesco de Felice.
CALLED the Bosco Verticale, the project is designed by Stefano Boeri architects and was originally created to combat the alarming levels of air pollution in Milan. The two residential towers are located in the centre of the city in the Isola neighbourhood. Milan is now one of the most polluted cities in the world and the Bosco Verticale aims to ease the environmental damage caused by urbanisation.
Given the lack of green space in the city, Milan’s environment does not promote biodiversity. The new plantings will provide an urban eco-system able to support a wide range of birds and insects. The architects believe the project has the potential to balance out the city’s environmental damage and to create a self-sufficient ecosystem.
On flat land, each tower equals an area of 10,000 square metres of forest. In terms of urban density, it is the equivalent of an area of single family dwellings of nearly 50,000 square metres. The verticality of the scheme means the urban sprawl is contained and the forest goes upwards into the sky.
The screen of leafy green trees and shrubs will filter dust particles, absorb carbon dioxide, protect the apartments from noise pollution, help ease the urban heat experienced in the city during summer and reduce the need for air conditioning to heat and cool the tower’s apartments.
The types of trees being used were chosen based on where they would be positioned on the buildings’ facades. It took more than two years of working with botanists to decide which trees would suit the buildings and the climate. The plants used were grown specifically for the project, pre-cultivated so that they would gradually acclimatize to the conditions on the face of building.
Although the architects have been working on the project since 2007, it is only now that the specially-grown trees and plants are being lifted into the two skyscrapers which are scheduled to be finished later this year. The towers, 110 and 76 meters high, will have more than 900 trees planted on their facades and balconies, each tree up to nine metres tall, plus 11,000 ground-cover plants and 5,000 different flowering shrubs.
“The Bosco Verticale is a system that optimizes, recuperates and produces energy,’’ says architect Stefano Boeri. “It creates a microclimate with a diversity of plants that produce humidity, absorb carbon dioxide and improve the quality of living spaces and save energy. The plants will be irrigated by filtering and reusing the grey waters produced by the building. Additionally Aeolian and photovoltaic energy systems will increase the degree of energetic self sufficiency of the two towers."
The construction of the towers cost 65 million euros, just five per cent more than an average skyscraper, and the project’s vertical design provides space that is equal to a large area of urban sprawl. The structure sets a precedent not only for new developments in Milan, but also for similar cities with the same level of urbanisation. The innovative concept is a viable model for reforestation within the confines of a developed city.
Click on photographs for full-screen slideshow
Artist's rendering of the completed Bosco Vericale towers with 900 trees, 5,000 shrubs and 11,000 ground cover plants.
One of the 900 trees being lifted on to a tower balcony. The trees will be three, six and nine metres tall.
Looking up towards the facades of the two towers from the ground ~ one is 110 metres high and the other 76 metres tall.
Cranes are being used to lift the trees on to the apartments' balconies.
The view across from the new towers to the smooth, glass and treeless facades of the skyscrapers opposite.
The trees arrive on site in Milan and are prepared to be lifted into the sky.
One of the Bosco Verticale balconies is prepared for planting with tall trees and a range of shrubs and flowering plants.
A tall tree is craned on to an apartment's balcony.
The raw concrete terraces and planter boxes before the earth, trees and shrubs transform this harsh space into a cool green retreat.
The balcony gardens are prepared with soil and irrigation before the shrubs are planted.
The tower's austere facade with a single tree being lifted into place.
A workman surveys Milan and the two towers before they are covered by a forest of trees and plants.