The term fourth nature is increasingly breaking through in discussions about greenery in our landscape. Ruderal, wild scrubland is to become an element of our cities and villages that we appreciate rather than exterminate. Is this possible?
Neighborhood overgrowth, mosses catching on dilapidated buildings or plants growing out of holes in asphalt have so far been an undesirable element for us. Urban greenery, until not long ago, was supposed to be planted and tended under a ruler, or there should be none at all. This attitude is changing by many elements — why? Thanks to researchers and landscape architects who are popularizing the term fourth nature.
What the term really means, where we can apply these „ecological uses” and what the future of urban greenery is tells us Kasper Jakubowski – a landscape architect who specializes in this topic.
Wiktor Bochenek: What is the fourth nature? What does this division consist of?
Kasper Jakubowski: Fourth nature is a concept that was introduced by Berlin-based wasteland researcher Ingo Kowarik. He created these categories by mapping the ecological succession of Berlin after the Second World War. Now there is a third generation of urban nature researchers who are studying Berlin and the natural processes in it after World War II.
The fourth nature, Professor Piotr Skubala says, does not mean the worst one, but it is one that we have dealt with very little, or even treated as of little value and not worth our attention or research. It includes wastelands and areas degraded by man, which nature is slowly colonizing.
The first nature is the one that is almost gone — areas of natural landscape, such as former primeval forests or single century-old trees. They are protected by reserves — for example, the Bielański Forest in Warsaw. The second nature is the one that we have already changed — farmland, farm forests and hay meadows. This is quite interesting, because when we stop using them, they automatically become the fourth nature after some time. The third nature is the one we are most concerned with today — manicured lawns, flower pots and city parks. She fortunately looks more and more natural.
When we talk about nature in the city, everyone sees this aesthetic, well-kept urban greenery. In addition to it, there are also many areas that are difficult to define — outskirts, uninvested areas or places losing functions. The wastelands vary in character — from the remains of industry, quarries or factories to sidewalk cracks or walls overgrown with vines. The trend of interest in fourth nature has been going on since the post-war period, and even earlier, when the vegetation of medieval walls or the Roman Colosseum was inventoried and sketched.
Kasper Jakubowski
photo: Green City Poznań | UWI INWESTYCJE SA
A harbinger of change was the period of World War II, where, among other things, the British press published articles showing vegetation in bomb craters. Destroyed European cities created conditions for vegetation recovery not seen since the last glaciation. Species that had disappeared because their seeds had previously been deep beneath the foundations of destroyed buildings often returned there, and were brought to the surface.
Another concept is important — permanent ruins that are not rebuilt or demolished. It leaves them to nature, to overgrow, which is the answer to the rampant gentrification in Polish cities and the adaptation of post-industrial buildings. It's not worth adapting, commercializing and refreshing everything. Often this past in cities is ripped away — it's hard to see authenticity and the past in very „hardcore”, high-cost adaptation projects Nature is the added value of the ruins of historic buildings here. It is part of the natural identity of cities and regions. An example is the Ruhr region, where many such industrial „ruins” and artifacts are left behind, surrounded by lush vegetation.
Wiktor: Is fourth nature always associated with post-human sites that humans have altered?
Kasper: Fourth nature is most often the so-called empty spaces that man has exploited and destroyed, and which nature is filling in very quickly. This is no longer pristine nature. Scientists speak of a „new” wild nature, which we must redefine today.
This nature is undergoing intense changes, differing in species composition from ecosystems known from the past. Synanthropic, human-associated or alien species are appearing in it, and this group includes invasive species. This creates „new environments” and new conditions for nature's renewal.
Fourth nature also develops alongside us. All we have to do is „let go” a little, reduce mowing or herbiciding, stop plucking moss from sidewalks. We'll see how quickly lawns turn into meadows, and what will grow as soon as we deconstruct some space and let the greenery come in on its own. It has been doing it perfectly for millions of years!
Kasper Jakubowski's book is based on the author's many years of research culminating in his doctorate — it is available for free as an ebook
© Kasper Jakubowski
Victor: What is succession in the fourth nature?
Kasper: Ecological succession is the key word for understanding Fourth Nature landscapes. These are evolving landscapes that adapt to new climatic conditions. Succession means succession, nature has a number of mechanisms to adapt damaged land, contaminated soil or concrete.
At first, ruderal organisms like mosses and lichens appear. Then higher vegetation appears. This creates the conditions for the next groups of plants. This is a very drawn-out process and we don't need to accelerate it. If we let go of even a small section of asphalt or concrete we will see how quickly wild life appears on it, which is fascinating. This is a paradox! Man, through industrial activity, has unknowingly created new habitats that have often become enclaves for many species of plants and animals. This allows us to observe how nature copes with extreme conditions.
Nature is always subject to constant change. The so-called urban wasteland will also look different in 20, 30 or 100 years. An example of such succession is the Schöneberger Südgelände post-railroad park — there we can observe almost in the middle of Berlin how this succession of vegetation is rolling over the former track after more than seventy years. This forest is in constant reconstruction. Some parts are wooded more, and in other parts this occurs more slowly. This creates a very interesting living „laboratory of urban nature.” Such areas should be given legal protection.
It's also not succession in the classic sense, because alien species appear and with them invasive species, and it makes us ask to what extent we can interfere in this succession.
Wiktor: This is quite an interesting question. What should the design, or perhaps precisely the non-design, of this fourth nature look like? To what extent should we interfere with it. There is the question of the fight against invasive species, to what extent should it take place in areas of fourth nature?
Kasper: There is a whole concept of „new ecosystems” so-called novel ecosystems. What we have here is an experiment. Certain communities develop on very transformed land and develop on their own. This is a kind of experiment on how this evolution will take place. The answer to the question of whether to interfere and always remove invasive species, in my opinion, is not clear.
As a landscape architect, I advocate a flexible and pragmatic view. If we are dealing with first or second nature, there we should exterminate foreign and invasive species if we have the funds to do so. In the case of fourth nature, we should be more flexible. This can be observed and intervention can be kept to a minimum. There are plants of the genus Reynoutria, or knotweed, which are biocenotically insignificant and wildly expansive. If we have the opportunity, we should remove knotweed even in the context of the fourth nature. And, above all, make sure that we do not create new sites for them, which repeatedly happens on construction sites or road construction.
If we want to preserve some valuable vegetation communities, it is important to remove invasive Canada goldenrod and late goldenrod. If we „let go” of these areas, sooner or later a forest will grow there. I am in favor of preserving, including in cities, areas without interference. Even if they are not naturally important, it is worth watching how this nature adapts and develops on its own. A greater threat than invasive species is often reclamation at the expense of nature or re-development of these areas.
We can try to interfere in other ways, for example, by inoculating forest undergrowth plants in successional forests, since they would not have appeared there on their own after the break with natural forests.
It seems to me that the 21st century and changes in the natural environment, show that we need any nature that permanently protects the soil, stores water, thrives despite pollution. I recently listened to an excellent lecture by Dr. Christopher Swierkosz, who showed that in worst-case scenarios, forests in our latitude will begin to disappear, become diseased or their growth will be disrupted. Adaptation of species such as pine, spruce, rowan birch , which will begin to die as a result of fungal diseases and rising temperatures, will no longer be possible. Then perhaps we will look with more kindness on those invasive species of trees that we are so exterminating. They may be the hope for cities in the future.
Lebanon's quarry, which has become an ecological use
photo by Jerzy Opioła | Wikimedia Commons CC BY-SA 4.0
I observe, for example, the glandular godwit, a species that is an indicator of an urban heat island. It can grow in any conditions, in the cracks of buildings or at curbs. In 2022, in August, when many trees withered, he was incredibly vigorous. In 20-40 years, this species could prove to be a lifesaver for cities and forests. We are facing huge changes, transformations on an unprecedented scale, and it seems to me that we need to watch how nature adapts to them. This is a huge challenge for the „old” school of conservation — what do we want to protect today and why.
Research conducted by Professor Piotr Sikorski 's team at the Warsaw University of Life Sciences, which studied wastelands in Warsaw, points directly to the role of fourth nature. Even those bracken and areas that are going wild absorb twice as much carbon dioxide as park lawns. This is an argument for not mowing, but also for protecting these secondary wilderness areas, even if we don't perceive them as „beautiful” at all. These landscapes work for us!
Wiktor: Why should we care more about the fourth nature?
Kasper: It's a question of design. The fourth nature is a challenge for designers and designers. Our cities face the challenge of restoring biodiversity. The optimistic thing is that it is possible to have more of this nature, and greenery is friendlier to us and the creatures living there.
What we need in cities is a little more chaos and less orderliness. It's a matter of less maintenance costs for greenery and our survival. We need to leave nature also in the city a little more space where it can manage itself. This applies to architecture and designing niches in it where we will introduce greenery or it will colonize them on its own. This also shows that we are facing less design and more inclusion and initiation of certain processes that we will control.
Wojciech Kosinski said that we also need a new environmental aesthetic. It can't be a simple acceptance of „weeds”, weeds and wildness, because it seems to me that viewers and developers won't accept that. We need to incorporate the fourth nature in such a way that it too is aesthetically pleasing.
Art comes to the rescue here. In Berlin on Schöneberger Südgelände, artists and sculptors were invited to design paths among these self-sown trees. This is also a valuable direction for change. We can suggest a suitable substrate to limit succession, or expose certain species. We can change the plant cover catalog and allow species that we used to eliminate from the landscape.
Victor: For example?
Kasper: Maidenhair, wild carrot, sand reed or elderberry, or my favorite: mullein or ash, or thistles. These are species that endure very difficult and harsh soil conditions, enduring salinity. How we expose them properly in projects, they can repay with very interesting aesthetics. Ruderal thistles have become popular in boho style.
Wiktor: Can we use the term Fourth Nature to replace the word wasteland? How do we replace this word, which nevertheless has a pejorative character?
Kasper: A „wasteland” is something useless and worthless, which is an investment reserve or a field for revitalization at the expense of greenery to be planted from scratch. It is a much narrower term than fourth nature. Fourth nature, as I write about in my book ("Succession of Nature and Functions of Urban Wastelands"), includes those areas that have been abandoned by man, but also those that have been re-adapted and are now under legal protection. Here we have different approaches and schools of thought to the fourth nature. In the UK, many of these areas are protected because of the natural processes that spontaneously occur in them and the mosaic of habitats. Industry is creating. In others, ambitious environmental restoration projects are underway and ecosystems and their functions are being restored.
All these diverse parks form a whole network of green areas permeating the cities, in which there must also be room for „unorganized”, uncontrollable by man nature. That's what this story is about.
In Berlin, for example, some areas are left to their own devices, but parks are also being created to connect third and fourth nature.
Schöneberger Südgelände
Photo: Assenmacher | © Wikimedia Commons BY-SA 4.0.
