In the rapidly renewing Porta Nuova district of Milan, two brand new residential towers­one 250 feet and another 360 feet-stand well above the terracotta roofs of their ancient neighbors. Their stark white balconies jut out from what can be seen of the buildings’ smooth black facades. However, the distinctly modern character of the development-which was completed in 2014-is far from the project’s most distinctive feature. When the wind blows through Milan, these two buildings, known as the Bosco Verticale-come alive.

Because with every breeze, the thousands of branches and leaves protruding from the two buildings shimmer and sway. There’s something growing on nearly every surface of Bosco Verticale, which translates to “the Vertical Forest.” All told, the shrubs, ground cover, and 730 trees that make up these towering gardens represent a population of plant life equivalent to a hectare of forest.

Treescrapers

The work of Milanese architect and planner Stefano Boeri, Bosco Verticale has become the standard-bearer for an emerging class of buildings known as the “treescraper”, a phenomenon in which buildings are designed to incorporate significant populations of green life as they rise high above the ground. Placing plants on balconies is nothing new, but the scale of Bosco Verticale’s organic integration is. Altogether, it’s not a cheap idea. In construction, the buildings had to be reinforced to handle the added weight of the trees and soil, which may just increase the buildings’ carbon footprint and negate many of the promises of sustainability-and that’s just the startup cost. Every four months a team of daring botanists belay down the building on climbing ropes to trim the trees.

Incorporating ideas of high-density development and urban biodiversity, Bosco Verticale is as much of a feat of urban planning as it is an impressive feat of imaginative engineering. The development boasts many of the same benefits one might achieve with a park or green space, providing a carbon sink and habitats for native bird and insect populations.

However, it claims to manage to accomplish a host of sustainable initiatives by harnessing the most natural technology available, nabbing it a LEED-certified gold rating in the process. The diverse array of plants, selected by a team of consulting horticulturalists, helps filter dust, and air pollution, create oxygen and help regulate the temperature of the buildings, helping keep air conditioning costs low.

A Look Ahead

If Bosco Verticale is the pioneer of the “treescraper” movement, the helix-shaped Agora building in Taipei, Taiwan is the next-generation challenger. Designed by Vincent Callebaut Architecture, the dramatic building [still in progress] will feature twin towers wrapped around a fixed central core, resembling a strand of DNA. Like its Milanese counterpart, the building’s balconies will host extensive vegetation­in this case, vegetable gardens, and fruit trees for the residents’ food needs. A rainwater harvesting system enables the gardening initiative to approach true sustainability, and a light funnel design will make the most of the daylight the tower receives.

While proponents of “treescrapers” may tout their overall sustainability, don’t expect to see towering forests proliferate any time soon. With higher construction and maintenance costs than their conventional counterparts, it will always be more efficient to plan for more parks and green spaces as we develop new neighborhoods or revitalize old ones. There are also physical limitations to the treescrapers’ development: as buildings climb higher, the environment for trees becomes less hospitable, as wind and extreme temperature may take their toll. Most trees, remember, grow in forests around other trees and supported by complicated ecosystems. By removing them from their natural context, we’re also altering their chances for survival.

The true value of the “treescraper” may just lie with the quality of life. There’s no denying our affinity for living in the canopy. Studies have shown what one might suspect: that our physical health and psychological well-being improves when we’re in close proximity to trees. Who’s to say the luxury residential market won’t demand condos that feel like forests?
Boeri, however, is doubling down on his vision. His next project, La Tour des Cedres, or the Cedar Tower, is scheduled to start construction in Switzerland in 2017. One thing’s for sure: if you’re a Swiss gardener, it may be a good time to take up climbing.

Originally Published in:

THE NETWORK / JUNE 2016 – Amazing Buildings