The new concrete jungle? Condos are growing up with vertical forests


With the unstoppable boom of urban construction and the overwhelming rise of tall glass and steel towers, our green spaces are gradually disappearing. But the good news is that there’s a new architectural revolution happening around the world, with the mission of improving our climate, air quality, and big city living conditions. And now it’s arriving in our own backyard.
The Toronto architecture firm, Brisbin Brook Beynon (BBB Architects) is designing a new residential building — in line with John Tory’s vision to transform the city into an ecological metropolis with an urban canopy comprising 40% of the city. The firm plans to construct a 22-story condominium wrapped by a living, intertwined “vertical forest” of more than 450 trees.
The concept was inspired by Milan’s Verticale-residential towers, two residential buildings that host on their staggered balconies about 11000 plants and 800 trees (some as tall as 30 feet and can grow over three building floors), along with geothermal heating systems to counteract the smog and heat of the city.

Design Walk by BBB Architects. Image courtesy of Urban Toronto.

BBB Architects are designing the condo like a hillside covered in trees, sloping upwards with giant terraces. The vision is for the condo’s cascading vegetation to reduce our overall carbon footprint and extend green space beyond the limits of the ground.
Construction for the Designers Walk project is scheduled for completion over the next two-and-a-half years. The vertical forest design will be a first in Canada, but isn’t without its critics.

The high-tech of growing a vertical forest

Vertical forest buildings need technology that’s just as forward-thinking as their design. In fact, one of the firm’s partners rented an Airbnb in Il Bosco Verticale to learn more about the towers’ inner workings of the towers. He had traveled all the way to Milan, only to realize that most of the technology and systems actually originated in North America.
The technology team behind BBB’s vertical forest are experts in horticulture and agriculture, including Robert Wright, University of Toronto dean of forestry, researchers from the Vineland Research and Innovation Centre, and Marc Vanden Bussche of Vanden. They’re developing a specialized system to monitor and irrigate the trees across the building’s terrace surfaces. From water intake to nutrient levels, and external conditions (like wind velocity), sensors will connect condo planters and monitor key metrics for each tree.

Bosco Verticale vertical forrest in Milan. Image courtesy of Arch20.

The building will also require a dedicated maintenance team, to care for the trees and navigate the canopy of balconies. A team of arborist-climbers or “flying gardeners,” specializing in high-altitude pruning will check and maintain the plants. Indeed, nobody wants a branch to drop 200 feet off a balcony. And another team will oversee the automated irrigation system.

Urban oasis for the environment and big-city dwellers?

Urban canopy projects, like the new Designers Walk condo, are designed for creating environmental benefits like:

  • Absorbing carbon dioxide, releasing more oxygen, and purifying the air
  • Offsetting the city’s heat island effect by filtering sun rays
  • Giving migrating birds, bees, and butterflies more green space
    As well, the vertical forest will ideally create a sustainable microclimate between green roof and ground spaces, so species can pollinate between the two. BBB Architects says that vertical forest living also has its benefits for residents. The foliage not only blocks out city noise, but it improves the quality of life for its residents — by bringing them closer to the natural world.
    Some critics, however, caution that this vertical oasis is more of a design trend than a feasible reality. There’s the concern that vertical forest planters aren’t big enough to allow the trees to survive long term. According to architecture critic Tim De Chant, trees taken out of their natural habitat can’t thrive on top of tall buildings, because of the extremes of wind speeds, temperatures, and high precipitation. And the trees the highest up on the building will be subject to the most stress. “Trees just weren’t made for such conditions.”

    Bosco Verticale known as the most beautiful and innovative skyscraper in the world. Image courtesy of Dimitar Harizanov.

    Lloyd Alter, a professor at Ryerson, says that vertical forests use more concrete than traditional buildings. And that concrete creates carbon dioxide. “It would take a hundred years for the trees in one of these structures to compensate for the carbon footprint the building creates,” he explains.
    And there’s also the cost. The vertical forest adds a premium of more than $20-million to the cost of the 22-storey building. And then there’s also the premium tenants and buyers will have to pay for the maintenance team that will keep the trees alive and growing. Acrobatic maintenance skills off building ledges don’t come cheap.
    Realistically, vertical forests aren’t going to end climate change anytime soon. But as Robert Wright says, “the densification of our cities is important.” There’s real hope for vertical forest buildings to help increase biomass, biodiversity, and canopy cover. And a new concrete jungle might just pave the way for more new green infrastructure projects in the future.
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