December 15, 2011

Column | Korky Koroluk

Vertical forests for a green future

One of the good things we can do for our beleaguered plant is to planet more trees.

Trees help keep us cool, clean the air we breathe and store carbon dioxide. And simply gazing at a grove of healthy trees is, I think, good for the soul.

Cities all have trees. Some have urban forests. But some have no space to plant forests, so what do they do? Well, you could always plant vertically.

A vertical forest, Bosco Verticale, is going up right in the centre of Milan, Italy. When finished, it will be 27 storeys tall, 40,000 square metres, and will have cost €65 million, or about $88.6 million Canadian. A 20-storey neighbour will be built after the first building is occupied and running well.

The big question, of course, is the trees. Architect Stefano Boeri expects to have trees of three, six or nine metres tall on the balconies, along with a variety of shrubs and flowering plants.

But some of the trees planned, including oaks, have deep root systems, which means a deep growing medium. The total weight is likely to exceed, by far, any load normally expected on ordinary apartment balconies. Also, branches flail around during storms, and the trees sway. That would generate loads that are different from loads ordinary apartment towers are subject to.

Boeri says the building was made possible only because of a new collaboration between architects, engineers and botanists. He says he’s had to explain many times just what the engineering and horticultural problems are involved in growing nine-metre oak trees on the 20th floor in the centre of a busy modern city.

So far, though, the general public hasn’t been told much about those problems, and the photos and renderings available don’t give many clues. His website (www.stefanoboeri.net) is interesting, but doesn’t answer the questions.

Boeri is many things: an architect in private practice, editor of Arbitare magazine, former editor of Domus magazine, and a professor of urban design. He has served stints as a visiting professor at both Harvard and Massachusetts Institute of Technology.

He also founded Multiplicity, an international research network dedicated to the study of contemporary urban transformations.

He is a visionary at a time when the world desperately needs visionaries, people who can step to one side and view a problem from a different perspective.

Bosco Verticale, is just the first element in his vision, a proposal he calls BioMilano. His plan is to create a green belt around the city, and take over several dozen abandoned farms on the outskirts and restore them for community use.

Boeri is not the only architect who wants to grow trees on balconies.

In Valencia, Spain, the Dutch architecture group MVRDV, is working on a high-rise social housing project. Some of the building’s 96 apartments will have a balconies cantilevered eight metres out from the façade. Each will have a deep pit so large trees can be grown. The vision there is to grow not oaks, but contribute to the food supply by growing orange and lemon trees.

In S<0x00E3>o Paulo, Brazil, Triptyque, a group of Brazilian and French architects, has built Harmonia 57, a modest-looking mid-rise building that is arresting because of the exterior sprinkler system which is used to spray mist on the plants growing on the building’s façade.

The façade is of porous concrete with pits cut into it to accommodate plants. The porous concrete soaks up water provided by the sprinkler system and passes it on to the plant roots.

These buildings all carry the search for “green” farther than it has gone before, and no matter how they turn out, we will have learned much.

And that is important, as the gathering storm of population growth and climate change forms clouds on the horizon.

Korky Koroluk is an Ottawa-based freelance writer. Send comments to editor@dailycommercialnews.com

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