Bosco Verticale or Vertical Forest in Milan, Italy designed by Boeri Studios (Stefano Boeri, Gianandrea Barreca, and Giovanni La Varra) was the FIRST example of Vertical forest and have won prestigious awards worldwide.
There are two residential towers. Tower E & D with 27 floors and 18 floors respectively 112 and 80 metres high, housing a total of 800 trees (480 first and second stage trees, 300 smaller ones, 15,000 perennials and/or ground covering plants and 5,000 shrubs, providing an amount of vegetation equivalent to 30,000 square meters of woodland and undergrowth, concentrated on 3,000 square metres of urban surface.
This Tower of Trees, occupied by Humans provide endless benefits not only to the user but the surrounding of the city, As cities generating 70% of Carbon Dioxide leading to more warmer and polluted environment. Some Features that are majorly counted are:
Pollution The greenery acts as a buffer between the city and the apartments by absorbing polluting particles, noise and sequestering carbon whilst also producing oxygen and improving air quality.
Energy efficiency The green façade results in reduced energy consumption due to increased insulation against outside temperatures and shading. This keeps the building cooler during summer – a reduction of nearly 3 degrees – and warmer during winter, reducing the need for active cooling and heating of internal spaces. Overall, the building was designed to achieve significantly lower energy consumption than a typical building in Milan.
Biodiversity Hosting around 100 different plant species, the façade promotes biodiversity by providing a vertical urban oasis for nesting birds and wildlife.
Urban heat island The cooling benefit of the façade contributes to reduced temperatures in the vicinity of the building. This further reduces the need for cooling capacity and the urban heat island effect often found in cities caused by the thermal mass of concrete and asphalt that absorbs the sun’s radiation, meaning city centres are typically several degrees hotter than the surrounding countryside.
Internal comfort Shading from the green façade results in natural temperature control, light management and improved air quality. During summer months, some residents rely purely on natural ventilation to achieve comfortable internal temperatures. In extreme external temperatures, an underfloor passive-cooling system, fed by groundwater, further helps prevent overheating.
Occupant satisfaction Residents of the building have expressed a high degree of satisfaction with comfort levels and thriving green areas.
The towers are mainly characterized by large, staggered and overhanging balconies (each about three meters), designed to accommodate large external tubs for vegetation and to allow the growth of larger trees without hindrance, even over three floors of the building. All the maintenance and greening operations are in fact managed at the condominium level in order to maintain control of the anthropic-vegetal balance. Irrigation is also centralized: the needs of the plants are monitored by a digitally and remotely controlled installation while the necessary water is largely drawn from filtered effluent from the towers. All these solutions overcome the still essentially anthropocentric and technical concept of “sustainability” while moving in the direction of a new biological diversity.
As installing a living feature has it’s own benefits and challenges, there are few challenges that need to be countered.
Challenge of Weight of soil and trees – To support the extensive planters that house the ‘green façade’, the architects designed cantilevered concrete terraces to sustain the added weight of the vegetation. The plants were installed into concrete containers with different dimensions, depending on the type of plant. Trees were planted on a 1-meter-thick soil layer, while shrubs on a 50-centimeter-thick one.
Challenge of Water Irrigation – A water draining and root-resistant system, composed of Polyethylene and geotextile fabric layers, was positioned between the soil and the internal waterproofing membrane of each container. The plants are watered by a complex centralized system divided into sub-sectors and equipped with compensated drippers that filter and re-uses gray-water from the buildings and recycle the groundwater utilized by the geothermal heat-pump-based VAC system of the complex.
Challenge of Maintenance – The maintenance of the vegetation is “facilitated” by two cranes installed on top of the towers, which allow the gardening staff to operate on the plants from the outside.
Challenge of Wind Pressure – A 1:100 scale model was tested in the wind tunnel of the Politecnico di Milano to help calculate the center of gravity and forces the building would be subjected too even under extreme wind forces. Full-scale tests of trees were performed in the “Wall of Wind” tunnel at Florida International University.
Can Milan’s Vertical Forest be applied also to non-luxury residential developments? To date, the exclusive purchase prices and maintenance costs of the Milanese complex make it attractive only to a wealthy clients. This is a need and a responsibility to think and to develop such spaces and area for the well being of us and our environment.
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