CITIES THAT FUNCTION LIKE FORESTS

Using Nature as Model

I’m sure that, by now, you’ve probably heard about biomimicry — a practice that learns from and mimics the strategies found in nature to solve human design challenges. But what if it’s just another bio-buzzword? A new eco-fad? I’m glad you are sceptical. I also have a well-developed radar for green-washing. Countless so-called ‘green solutions’ just shift the focus to create a new problem elsewhere. But biomimicry is different. It is a systems-based approach based on a set of principles that leads to a whole new way of seeing and thinking. Biomimicry is grounded in science and has been around since 1997.

The problem with traditional construction

Before we jump into biomimicry’s proposed solution, we first need to look at the problems this paradigm attempts to address. Apologies, but it starts with a bit of a downer. Together, the building and construction industry is responsible for 39% of all carbon emissions in the world. Let that sink in.

Broken down, 28% of this statistic can be attributed to operational emissions deriving from energy used to heat, cool, and light buildings. The other 11% is embodied carbon associated with the materials and construction processes. Just think about the massive of amounts of energy required to produce concrete, the high temperatures needed to produce steel and glass, and to turn silica sand into a liquid. Sadly, the landscape industry is no better. The concrete, plastic pots, irrigation systems, aquifers of water used to make lush vegetation grow in places where it naturally doesn’t are not green at all.

I am not a pessimist, but I do wonder: How will our cities’ award-winning buildings age? Can they easily evolve and be adapted to new uses? And how will they fare in the event of a calamity like war or an earthquake? All that steel and concrete and glass just becomes more landfill. When I see the sparkling skyline of modern cities, I wonder what the conditions are like in summer? With all those shiny surfaces reflecting heat from glass, the roofs, and dark materials absorbing heat. Between all the roads, parking, and paved surfaces — how can there be any infiltration of rainwater? The hard surfaces and lack of infiltration is a large contributor to the urban heat island effect. Most cities are impermeable, and Cape Town is no exception. It receives three times more water per annum than it requires, but most of it is piped out to sea through the stormwater system.

We are not the first to be battered stronger by hurricanes. During Catrina, out of over 740 oaks only four died. The 1000-year-old Seven Sisters Oak in Louisiana has seen a few hurricanes. Its spiralling trunk and branches as well as the design of the leaves allow it to flex and go with the flow. The shape also creates a Fibonacci sequence for least friction, and is designed to drop branches with self-sacrificial layers.

The roots of live oaks are entwined with other roots, in some cases even grafted together for adaptive loadbearing.

The problem with biophilic design

In the 21st century, when we ran out of space to plant trees in cities, designers found ways to green differently: on walls and roofs. I have my doubts about the sustainability of 'living walls' and ‘green buildings’. Take Bosco Verticale completed in 2014 in Milan, Italy, as an example. The two residential towers pioneered the idea of a vertical forest, and is often used as the inspiration for the green building movement. More than 2000 m² of trees and shrubs were planted, but large cantilevered concrete terraces were needed to support the additional weight of the planters that house the ‘green façade’.

In the words of the World Green Building Council, ‘Given this approach does rely on extra building materials, ultimately increasing the embodied emissions, future projects must further revolutionise the concept by balancing the benefits of enhanced greenery with innovative solutions to the resulting additional materials required.’ A careful euphemism for the fact that the carbon footprint of the building was way higher than normal.

Don’t get me wrong. Biophilic design is a noble pursuit. Incorporating more plants into our cities and buildings will satisfy our innate desire to affiliate with nature, promoting our mental well-being in the long run. Yet, while biophilia has its aesthetic benefits, it’s not going to solve the climate crisis. It’s not really addressing the fundamental problem of reducing harmful impacts on the environment with greater efficiency. So then, how do we change our industry? How can we design and build structures and landscapes that won’t deplete the planet? How do we create healthy, productive environments for end-users?

There is hope

On the upside, these challenges hold plenty of opportunity for us to make a massive difference for good. Human beings are immensely creative and intelligent: we have the ability to think critically and make changes. One such thought leader is Janine Beynus — the founder of the global Biomimicry Institute whose original talk titled ‘Cities that Function Like Forests: Biomimicry Maps a Sustainable Future’ inspired this article. From her, I learned that a sustainable world already exists in nature, right here on our doorstep. Plants are manufacturing material using a few basic low-energy elements that are freely available: C02, H20, sunlight, and nutrients. Nature is resilient: it creates shelter, copes with floods, survives summer droughts, and extreme winds. Therefore, it should come as no surprise that biomimicry has grown exponentially in the last decade as more and more people pay attention to the wisdom found in the natural world.

The Bank of America Tower filters air and releases it three times cleaner.

We tend to spend a lot of time learning about nature, while biomimicry turns the lens around and asks: what can I learn from the natural world? And the reason we’re learning from it is in order to emulate it. Not ‘copy’, because copy means you don’t really understand it. By definition, biomimicry is the practice of learning from and emulating nature. It recognises that 3.8 billion years of evolution and natural selection has resulted in highly efficient organisms and solutions to a diverse array of challenges. We have a bottomless treasure trove of energy-efficient, low-toxic, and time-tested innovations right at our fingertips. The ultimate reference library. All we need to do is look!

Sharklet biofilm is the world’s first technology to inhibit bacterial growth through pattern alone. The distinct diamond pattern mimics the shape of the dermal denticles found on a shark’s skin. Unlike whales and sea turtles, sharks are resistant to algae and barnacles attaching to their bodies, which prompted scientists to investigate the skin’s surface.

Putting theory into practice

What would it take for our cities to function like forests? Not look like — we are talking performance: clever ways of cycling nutrients, dealing with waste, purifying and cooling the air, taking up CO2 and producing O2.

Life creates conditions that are conducive to life

Nature is restorative, regenerative, and life-sustaining. It purifies water and air, moderates temperature extremes, sequesters carbon, enhances soil fertility, decomposes waste, among many other ‘ecosystem services’. The dream is that cities would be functionally indistinguishable from the wildland ecosystem next door. That means it is important to choose a local reference habitat as a benchmark. So, in the Cape we are not aiming for cities to function like forests; it would be to function like whatever the local vegetation type is (all 23 of them). Note, it is not a conservation exercise! If we want to move beyond mitigation (resource efficiency and reducing harmful impacts) towards creating positive ecosystem benefits, then we need ecological performance standards to measure these ecosystem services.

Almost like a new e-governance dashboard, this system will allow us to compare how many litres per rainfall event the wildland stores compared to the development next to it.

A company called Calera mimics the formation of coral reefs by making calcium carbonate cement from carbon dioxide and seawater.

No one can say this is impossible, because it is happening in the local habitat next door. These metrics and standards will enable clients and municipalities to meet and exceed their targets. It will encourage innovation and experimentation, leading to new materials, technologies, and approaches.

We can use concrete that sequesters carbon, design skyscrapers that purify the air, façades that produce energy, or rooftops that collect water from fog. Some of these have already been developed — the possibilities are endless!

Making sense of a new worldview

How will our built environments become vibrant, self-sustaining ecosystems? At the base level, we need to start with these three pillars: educate, collaborate, practise. The more we understand, work together, and apply what we learn in this field, the more we will move beyond ‘green tech' mitigation strategies to achieve climate regeneration. Everyone — engineers, architects, urban planners, politicians, and the general public — will understand the importance of the urban ecosystem, and will work together using biomimicry design principles to create cities that function in the same way natural environments do.

Ecological design metrics

Water collection and storage

# litres/storm

Solar gain and reflectance

% albedo

Carbon sequestration

# tons/acre

Water filtration

% pollutants captured

Evapotranspiration

% rainfall returned

Nutrient cycling

# tons/acre

Soil building mm of soil created

Temperature moderation degrees of cooling

Biodiversity

% diversity of native species

Slime mold (Physarum polycephalum) is a type of unicellular organism that is known for its unique behaviour and problem-solving abilities. It is capable of navigating mazes, finding the shortest path between two points, and even making decisions based on environmental stimuli. Scientists believe the organism may offer insights into the development of decentralised computing systems, robotics, artificial intelligence, urban planning, and efficient transport networks.

It’s not just about planting plants, but creating infrastructure and eco-structure that will contribute to the ecosystem services (e.g. sequestering carbon).

Fortunately, we have BiomimicrySA (biomimicrysa.life), founded by the late Claire Janisch, to help us get started. She worked closely with Janine Beynus and the global Biomimicry Institute to develop online courses, and left an incredible legacy. I have done the course on Life Principles and found it to be sound and very well thought through. Ultimately, biomimicry creates a framework to design into. Imagine how different things could be if we were all guided by life’s principles, looking to the success of survival around us?

This quote by Yuval Harari from Unstoppable Us: How We Can Shape Humanity’s Future is a wonderful call to action. May it inspire and spur you on to be part of the solution too.

MARIJKE HONIG Landscape designer, Botanist, and Author Think Ecologic @marijke_honig