World’s First Vertical Forest Being Built in Milan Plus “The Cult ‘Green Building’ of the Moment”

The 27-story Bosco Verticale in Milan, designed by Stefano Boeri as the world’s first ‘vertical forest’.  Click to enlarge.

If you can’t plant a forest horizontally in a dense urban setting, how about vertically?  The architect explains his design on his website here:

Bosco Verticale (Vertical Forest) is a project for metropolitan reforestation that contributes to the regeneration of the environment and urban biodiversity without the implication of expanding the city upon the territory. Bosco Verticale is a model of vertical densification of nature within the city….

The first example of a Bosco Verticale composed of two residential towers of 110 and 76 meters height, will be realized in the centre of Milan, on the edge of the Isola neighbourhood, and will host 900 trees (each measuring 3, 6 or 9 m tall) apart from a wide range of shrubs and floral plants.

On flat land, each Bosco Verticale equals, in amount of trees, an area equal to 10,000 sqm of forest. In terms of urban densification the equivalent of an area of single family dwellings of nearly 50,000 sqm.

The Bosco Verticale is a system that optimizes, recuperates and produces energy. The Bosco Verticale aids in the creation of a microclimate and in filtering the dust particles contained in the urban environment. The diversity of the plants and their characteristics produce humidity, absorb CO2 and dust particles, producing oxygen and protect from radiation and acoustic pollution, improving the quality of living spaces and saving energy. Plant irrigation will be produced to great extent through the filtering and reuse of the grey waters produced by the building. Additionally Aeolian and photovoltaic energy systems will contribute, together with the aforementioned microclimate to increase the degree of energetic self sufficiency of the two towers….

Christopher Woodward, director of London’s Garden Museum, has the story on “Living Architecture” with lots of images in the Financial Times.  He reports that in this case, the green design “adds only 5% to construction costs.”

Woodward has a great figure on Harmonia 57, an office block in São Paolo, which he calls “the cult ‘green building’ of the moment”:


Chart of Harmonia 57 hydration system

In Harmonia 57 mist is collected in an ingenious system of pipes, then used to water plants that grow in porous concrete walls.

Here is a longer story on Harmonia 57:

The office building “Harmonia 57” in São Paulo is a hybrid of building, sculpture and machine, which, with its informal outwardly appearance, blends in perfectly with the urban chaos of the city inhabited by 11 million people. For the innovative building concept, the French-Brazilian architecture firm Triptyque received the main prize in this year’s Zumtobel Group Award.

Back to Bosco Verticale, “the first element in [Boeri’s] proposed BioMilano, in which a green belt is created around the city and 60 abandoned farms on the outskirts are restored to community use.”

Here is a cross-section:

A cross-section of Bosco Verticale

The architect has more images on his website that spell out  all of the environmental benefits of his design:

The biggest issue I can see is what happens to the trees and branches in a severe storm with high winds.

Still, a very original conception, and need a lot of such original ideas in the coming years and decades.

13 Responses to World’s First Vertical Forest Being Built in Milan Plus “The Cult ‘Green Building’ of the Moment”

  1. Two things are obviously needed to make our buildings greener:

    — Put the buildings in walkable neighborhoods, to reduce automobile dependency.

    — Make the buildings energy efficient, to reduce heating and cooling costs.

    This looks to me like an architect’s attempt to attract attention to himself. Those trees seem to have very shallow roots and to be very exposed to the winds, so we will see if they survive.

  2. Merrelyn Emery says:

    Its a fantastic idea, a modern, elaborate version of the old dirt roof, and you are right, we need lots more ideas like this. My question is about the 6 and 9 metre high trees and the area and depth of soil required for the roots of trees this height. Or are these taller ones just going into the ground around the buildings?

    Also, do the occupants have a choice between all shrubs and trees or some vegies as well? ME

  3. Quiero Bosco Verticale!

  4. dan allen says:

    I’m all for trees & everything, but…the same resources applied to transforming actual farmland from conventional industrial model to perennial polyculture/permaculture would probably go a LOT further. …We don’t have time or resouces to mess around with cute ideas. See

  5. Mike Roddy says:

    Great idea, especially since it’s in Italy, where they have enough sense to build out of inert materials such as stone and concrete.

    The opposite impact in the US would be greater. It takes about 15,000 board feet of wood to frame a good sized apartment- code approved for up to four stories. These days, that board footage can be up to an acre of a tree farm for just one apartment. By employing FSC certification (clearcuts and tree farms allowed), it could even get a LEED rating.

    We need to rethink all of this, starting with educating architects.

  6. Lance Parker says:

    Two comments:

    1) Roots are very powerful and can break cement and bend steel. I don’t see why woody plants are needed.
    2) Dan Allen, we need cute ideas for two reasons; we don’t have all the answers yet and it makes life meaningful to create new knowledge and technology.

  7. Rob Jones says:

    From my perspective this is not such a bad thing. This timber represents sequestered carbon. If building standards were raised to a point where these building would last for longer time periods this would be better.

  8. Joan Savage says:

    Something more light-weight than trees, like vining plants on a trellis, have been used successfully for years to cool walls and porches. Leafy screens of sweet potato leaves, bush beans, clematis or Dutchman’s breeches might have fewer engineering problems.

  9. Joan Savage says:

    Trees need sunlight all-round; the diagram which suggests they could flourish on one side of a building shadow, and in the shade of overhanging terraces, is fanciful at best.

    The engineering for supporting the combined mass of soil, water and growing tree tissue isn’t obvious either. I’d expect arches or something.

    Safety from falling branches hitting the pavement several floors below would also be desirable.

  10. Davos says:

    This is a very neat concept. It would be awesome to see more green in an urban context.

    I wonder how much success it would have in a deciduous area … imagine OSHA’s view of the high-wire raking ;) …Or if they just leaf-blow it out a few stories up onto the folks below.

  11. Geoff Beacon says:

    “Green buildings” sometimes create very large amounts of greenhouse gasses in construction. Have the designers estimated this? For example the Beddington Zero Energy Development (BedZED):

    the embodied environmental impacts of BedZED’s construction materials are within the same range as standard UK housing. The total embodied CO2 of BedZED is 675kg/m2, whilst typical volume house builders build to 600-800kg/m2.

    So a 100 sq metre flat has a carbon footprint of 67.5 tonnes CO2e – many years of your carbon ration.

    The scheme looks as if it has a lot of high carbon footprint concrete – and steel too?


  12. adelady says:

    I’d agree the 6 and 9 metre trees look a bit ambitious for terrace gardens. They’d be fine on the rooftop and maybe on the lowest levels.

    Of course there are some trees that could be useful. It’s common practice in gardens and orchards to plant figs over slate or a concrete paver to restrict the root run and get early production as well as a more manageable size. Presumably there are other trees that are amenable to this sort of control, or cultivation on dwarfing rootstocks would be a better guarantee for some.

    I think vines would be a better bargain for a lot of terrace planting. Just avoid the self clinging types.

  13. marc says:

    Tree roots- take a look at any tree that has been uprooted by a storm. by and large roots are only 1-3′ deep for a 20+ year old tree. trees don’t generally have a “taproot”

    4 meters=12 feet more or less. a 12 foot maple has a trunk diameter of 1-2″.

    Were i work we do have some extensive rooftop plantings. in fact we had to crane in a 6″ caliper London Plane tree that was close to 3 tons even that root ball was only about 36″deep and the tree was close to 20′ tall.

    yes roots are strong. but go to any nursery and ask them to see a tree or shrub that is pot bound. 1/8″ of plastic pot can easily contain roots. root that break up concrete walks and driveways or sewer pipes are not “strong” they are just displacing the dirt around them as they grow in diameter…

    What happens when a tree dies?
    weight loads, maintenance, micro climates

    I think through proper plant selection it could work… Is the payoff there…