The vertical forest - it conjures up images of a treetop community in the sky or an elaborate outdoor education venue and perhaps both of these things are present if you think about it. In essence, vertical forests are sustainable residential developments sprouting up in the heart of our cities, providing a unique solution to population growth and environmental issues combined.
The first example of a vertical forest or ‘Bosco Verticale’ was envisioned by Italian architect Stefano Boeri, simply as homes for trees that also house humans and nature. These two skyscrapers sit side-by-side in central Milan, 80 and 112 metres high, fusing together over 20,000 different types of vegetation - trees, plants and shrubs on the exterior of the building; with a place to call home for thousands of residents.
Since it’s completion over six years ago, it’s become much more than imagined - an aspirational example of biodiverse architecture to be realized by cities the world over.
Why are vertical forests necessary?
The consequences of climate change are much clearer now than they ever have been and the speed at which our environment is changing is phenomenal, resulting in many of the natural disasters we contend with today. Heat waves create the urban heat island effect, floods, storms, droughts and forest fires are all increasingly threatening to our very existence.
According to the UN, cities are the one major contributor to climate change, consuming 78% of the world’s energy and producing 60% of all greenhouse gas emissions. This is astonishing given that they account for just 2% of the world’s surface so unsurprisingly they’re in the spotlight to reduce this imprint.
Efforts such as the tree canopy initiative from Toronto city, aimed at introducing more trees to sidewalks, just doesn’t go far enough to mitigate the human impact on the environment, enough to make a difference anyway, and moreover there isn’t the space for them. Vertical forests or urban forests are a very viable way of mitigating the multiple effects of climate change.
Never underestimate the power of a tree
The sheer number of trees and plants involved in creating these forests in the sky expedites a number of environmental benefits that make them appealing to occupants, city planners and developers alike.
Trees and plants are capable of absorbing carbon dioxide emissions like nothing else and they also produce oxygen to emit back into the atmosphere resulting in a much purer air quality. In a single year a mature tree can absorb over 48 pounds of carbon dioxide.
Vertical forest buildings are designed to enjoy significantly lower energy consumption than others. The habitat growing on the outside helps to keep buildings cooler in summer and warmer in winter and the green facadé also cools down the surrounding air temperature by filtering the sun’s energy unlike their concrete counterparts which magnify it back into the atmosphere. These characteristics reduce the urban-heat-island effect and produce cumulative reductions in energy consumption all year round.
Buildings can be largely self-sufficient, making use of greywater systems for irrigation, solar panels and if needed, ground water to top-up the water supply required.
Occupants of these buildings benefit from a superior level of comfort with the shading greenery acting as a natural temperature control and residents relying purely on natural ventilation during the summer months.
Just a few years after its completion, the vertical forest in Milan has established a new habitat for many different animal species that are re-colonizing the city. This indicates a healthier ecosystem capable of sustaining a wide variety of life.
Overall these buildings improve the health of their residents and the wider population and reduce carbon footprint.
Are vertical forests a passing trend?
Change does not always mean progress, however in contrast to some of the progressive buildings of the past there is a clear correlation between urban forest buildings and their purpose; in one word sustainability.
The concept has already been successful by anyone's standards, exported to Paris, Switzerland and China where the Milanese firm has been recruited to work on an entire forest-city. It’s also forming the basis for other developers of new commercial buildings such as Amazon’s ‘Helix’ in Virginia who will take the concept further to create a green community around an office and retail hub, becoming a pedestrianised destination for local residents to enjoy.
The first vertical forest in Canada is likely to come to fruition in the next couple of years at Developer’s Walk in Toronto. A project designed solely with conservation in mind, this building will feature 450 trees, each assigned a unique ID so that they can be monitored and maintained remotely.
Following on from urban forest development, the developers of this project suggest that there’s a whole new niche industry looming on the horizon, one where tree-cladding for new buildings becomes truly plug-and-play in nature.
There are still less than twenty of these structures in the world, what remains now is to learn from these early innovators to achieve even more.
Refining and evolving the market
Although the Italian project was a praiseworthy forerunner, Mr Boeri will admit himself that building a tower such as this to serve a densely populated area comes at a premium. Treating each building as uniquely as the climate it inhabits will feasibly reduce construction costs. They have been criticized for using too many embodied materials in the construction of the concrete overhangs which had to bear the weight of the mini-forests. Future projects must further enhance designs to incorporate more sustainable materials if they are to address these doubts.
Given the amount of transformation taking place in the world right now, It’s certainly a pertinent time for discussion on how this type of innovative design can be incorporated into both residential and commercial real estate developments for the greater good. Opportunity does exist for commercial real estate knowing that sustainability is high on the priority list of younger generations, including the future heads of family offices who place bigger importance on environmental philanthropy.
Vertical forests are places of outdoor education; the ultimate in treetop living, providing lessons in how cities can prevent climate change in the little space they have available and at the same time showing how humans and nature can co-exist and thrive again together. The future is bright (and a little more green).