Urban forests as the future
Creating a “green bomb” at a waste incinerator and turning a roundabout into an urban jungle are just two examples of the pioneering work performed by the landscape architects at SLA. In this interview, SLA’s CEO Mette Skjold explains how our cities will look like in the future.
Last year’s flooding across Europe was a veritable eye-opener with a clear message: our built environment must become more resilient and be better equipped to protect itself against severe weather conditions. Trees and plants are an important carbon sink and also play a vital role in adapting cities so they can deal with the effects of climate change. For example, the annual cooling capacity of an 80-year-old lime tree is equal to 200 refrigerators put together – a comparison that brings this slightly abstract concept closer to home.
Landscape architecture is therefore a discipline that has become ever more important over recent decades. One of the biggest and most successful players here is Danish studio SLA, whose projects include the planting on Copenhill, a waste incinerator in Copenhagen with rooftop park and ski slope. Mette Skjold, CEO of SLA, visited Vienna for a talk with architektur in progress and also held an exclusive interview with ubm magazine.
Not so long ago, there was a relatively distinct division between nature, planted space and built environment. What has happened in the meantime?
Mette Skjold: When I started out as an architect, I was at Henning Larsen for eight years, and I worked on projects from a construction perspective. And when I came to SLA, 90 percent of our business was advising other architecture firms. That has changed now, primarily due to climate change and its effects on ground sealing in cities.
It used to be a matter of finishing all the construction, and then came the question: “Okay, so now it’s finished, please can you put a bit of greenery here and there?” Nowadays, you are presumably involved right from the early planning stages.
SLA was set up 30 years ago by Stig L. Andersson. The company has always approached landscape architecture as something that should be integrated right from the start, instead of leaving it until after construction has been completed. Landscape architecture is not an afterthought, it isn’t about making a building more attractive. Rather, it is a complementary discipline that marries the built and natural environment. In the built environment there are so many challenges facing today’s cities. And landscape architecture is basically the sole discipline that is in a position to cope with these challenges from a holistic and cost-efficient perspective. The world wasn’t listening 30 years ago, but that has changed. Today, we are present from the very beginning of the projects – sometimes we are even there before the construction architects!
Landscape architecture is basically the sole discipline that is in a position to cope with today’s urban challenges from a holistic and cost-efficient perspective.
Mette Skjold, CEO of SLA
From what angle do you approach a project when you first start?
When nature is used as a point of departure for a design, and planning is oriented on landscape, first of all you need to take a close look at what is already there. What is the soil like? How is the climate? What kind of social and physical infrastructure is in place? There is so much leverage here that can be used to make cities more robust and resilient in the future.
After all, there have been more than enough examples to show the consequences of global warming…
In 2011 the rain and flooding in Copenhagen was so severe that it brought the city to a standstill for almost a week. And it cost over a billion euros to clear up and repair everything. Needless to say, it made the city sit up and take notice, but it also shows that changes in the climate are making it necessary for the people who live in cities to become closer to nature. The advantages are incredibly varied, on both a social and an ecological level.
What are the advantages, exactly?
On the one hand, we know that decarbonization is more effective if photosynthesis is nearer to the source of CO2 emissions. And on the other, nature-inclusive cities are better adapted to deal with changes in the climate. It makes rainwater easier to collect, and there are filters for noise and air. Besides this, nature creates a sense of belonging.
What effect does this sense of belonging have on us?
If we are close to nature in our everyday lives, it is more relevant to us and we feel that we are also a part of nature. This can influence the thoughts and actions of every single individual. For centuries, there was a dividing line between city and nature. It was as if we had ousted the problem, it had nothing to do with us.
Can you describe how you “design nature”?
We don’t imitate nature. Our intention is to take a look at how nature works in an ecosystem and introduce this to cities. This involves a lot of different aspects, but it is mainly about minimizing the risk of severe weather conditions in the future, and in general creating added value for the population. In other words, it is not about biomimicry, but more about biophilia and how nature-based design feels and functions. Instead of calling this “nature”, we call it “new nature”.
How diversified are you within the company?
We are very interdisciplinary. Biologists, plant experts and plant designers work at our company, and we also have designers for light and darkness, geographers, anthropologists, and even a philosopher who looks into the history of a place and how nature is anchored in the cultural heritage. We are increasingly working towards developing the value process and increasing the value proposition. This in turn gives rise to a new classification in the design, as biologists work differently to geographers, for example. If we represent the entire spectrum, we can increase the benefits and minimize the risks. For a very long time, we invested a great deal of energy in this focus, and now there is demand for it.
Decarbonization is more effective if photosynthesis is closer to the source of CO2 emissions.
Mette Skjold, CEO of SLA
Your projects take you outside of Scandinavia as well. Is your way of working universally applicable?
Our primary markets beyond Scandinavia are the UK, Canada and Abu Dhabi, but we also have ongoing projects in Germany, France and China, for example. It is definitely an advantage that we have an outside perspective. In many cases, it feels as if we are regaining what used to be an integral part of our culture but then fell by the wayside. Our approach is based on unearthing the aspects of a place that fill us with wonder and breathing new life into them. In other words, we work with what is already there. This increases the likelihood that a nature-based concept will be successful.
Does nature-based design have an aesthetic element to it as well?
Of course, there is also aesthetic value in nature-based design, but our aesthetic approach is based more on a scientific understanding of aesthetics. It is more about bringing all our senses together. For example, if you stand in the middle of a forest, all your senses are activated, and you are seized by this feeling of being part of something bigger. It is that kind of perception, feeling or event that we want to achieve in our work.
What is your advice for urban planners who are currently facing so many challenges?
I always recommend starting with a model and then moving forward using a process of trial and error. Maybe the result won’t be right the first time, but the important thing is to just get going and not allow yourself to become paralyzed by the fear of failure. Aside from that, it is most important to be on-site and understand the local context.
Can you give an example?
We are currently working on several very large development projects in London, where “Biodiversity Net Gain” was recently added as a specification. This stipulates that developers can only obtain planning permission if they create conditions that increase biodiversity on site by ten percent. There is no doubt that this is triggering change in how we will transform, redensify and expand our cities in future. A large number of investment projects are based on key performance indicators – almost as if our planet were made up of Excel sheets. But if you think about it, so much can be gained simply from looking at the characteristics of each place, and deriving future benefits from there. Taking this as your point of departure makes everything that you build and plant more robust and sound in the face of weather events that are becoming ever more unpredictable.
Most people understand the connection between landscape architecture and biodiversity. But how does social equity fit in?
We have a biologist working for us who conducted a study for her PhD thesis using the satellite data of 900,000 people across Europe. This revealed that children and young people who were in contact with nature every day had a lower risk of mental illness later in life. And so that is where the social dimension comes in. And if you see this as a socio-economic equation, you come to the following conclusion: integrating green space, parks and even woodland costs less than treating children later on after they have grown up without access to nature.
The city of the future will feel and function like a forest.
Mette Skjold, CEO of SLA
Can public space also influence how people behave?
Yes, in public space we are well placed to stimulate a new kind of behaviour, for example by enabling people to meet up coincidentally. After all, and looking beyond the health crisis, we are also facing the problem of increasing loneliness. Landscape planners attempt to orchestrate such encounters. This means seeing your neighbour when you take out the rubbish. Or the local shop becomes a neighbourhood hotspot when the new ice rink opens. On the one hand, it is about guiding social life in the city and programming space. And on the other, it is just as important to leave space unplanned so it can attract individual use.
Austria has a big problem firstly with huge land consumption and secondly with the high level of vacant properties. Can we take inspiration from Denmark in any way, seeing as it is a pioneer when it comes to green thinking?
Something that occurs to me in connection with vacant properties is that certain developers and property owners choose not to use huge billboards or advertise “To Let” in oversized letters. Instead, they attempt to improve the local environment. And we know that people are willing to pay 10 or 15 percent more for properties if the street has trees growing in it.
Copenhill is presumably one of the best-known projects where SLA made a significant contribution to its development. What was so special about the process?
The Amager Bakke Foundation was responsible for the construction project on the roof of the waste incinerator. They invited us to set out a nature trail and design the roof with as much natural landscaping as possible. It is very windy up there, and the site is in Copenhagen’s gloomy industrial harbour. And so our idea for the planting was cross-pollination, which is done by the wind. Copenhill acts as a kind of “green bomb” for the harbour area, as it were. In this project, we did a lot of things that we had never tried before. We planted relatively tall trees on a very steep construction, plus there was heat coming up from the power plant underneath. It took some very intense cooperation with tree farms and with the construction company to find a solution that adopted a new approach for the location.
Nature has to cope with a steady stream of changes. Can a nature-based design project ever be described as truly finished, with this in mind?
No, not at all. There is an official opening or launch, of course. That is the moment when the project is filled with life, and things get really exciting. Even after that, we continue to keep an eye on the project and make regular visits. It is so good to see how the plants we have chosen are actually growing and thriving. You can learn a lot from it too.
Although the ground sealing has been reduced by two thirds, there is still enough space for all road users, and the biodiversity has doubled within just a year.
Mette Skjold, CEO of SLA
Can you give an example?
At Sankt Kjeld’s Square & Bryggervangen in Copenhagen we removed 9,000 square metres of asphalt from a roundabout in a residential area. Then we planted 600 trees, plus a lot of grasses and perennial plants. It is also the city’s biggest rainwater management project to date and provides new space for local residents to relax in. Over time, it has turned into a veritable urban jungle, although it is actually part of the infrastructure. Although the ground sealing has been reduced by two thirds, there is still enough space for all road users. One of our biologists who is monitoring the project has established that the biodiversity has doubled within just a year. In other words, there are always a very large number of lessons learned that find their way back into our studio.
Does such a project attract criticism as well?
Some people believe that having woodland in the middle of the city is bound to increase the crime rate. But actually the complete opposite is true. According to a US study, cities with more green space have a lower incidence of crime. Criticism like that usually comes from people who don’t live there. The residents themselves think it is fabulous.
What gives you the greatest satisfaction in your work?
The best thing is when I see how people populate a place, and when I can collect stories and narratives from it.
During COP 28 in Dubai we visited our project Al Fay Park in Abu Dhabi, the first biodiversity park in the Middle East. It was overwhelming to see how the whole space was being used by such different people, from all age groups and across all nationalities. The green canopy created by the leaves on the trees had closed up above the pathways because the climate there allows everything to grow five to six times more quickly than here.
How do you see the city of the future?
One thing is certain: we cannot continue in the same vein as before, behaving as if we have four planets at our disposal. Although we haven’t yet built a nature-based city, we do know how it will work. The city of the future will feel and function like a forest.
Interview: Gertraud Gerst
Translation: Rosemary Bridger-Lippe
Photos: SLA, Mikkel Eye, Justin Hummerston, Magnus Møller and DroneRune