How does a forest think
Sanne Bloemink


On a sunny autumn afternoon, we are in the Amstelpark, overlooking the Amstel, an old mill, and two small Shetland ponies in a juicy meadow.

We are sitting on tree trunks, placed like a star around a central circle. This is the Parliament of Trees, built by artist Elmo Vermijs as part of the project Amstelpark – the trees narrate their story. For the design, Vermijs was inspired by the shape of parliaments and the way in which trees’ concentric growth rings carry (climate) history.

Part of the project is today’s meeting, a Trial in the Park – the trees speak out. With this speculative trial, Vermijs wants to question fundamental aspects of the legal system. In 1972, not only the Amstelpark was constructed, but the Club of Rome’s Limits to Growth report was also published. In addition, that same year, law professor Christopher D. Stone published the influential Should trees have standing?: Law, morality, and the environment, an essay in which he advocated rights for nature. Can we think of ways to give the trees of the Amstelpark a representative voice?

When all the guests have trickled in and taken a seat in the wooden parliament, the three judges stride stately through the circle in their black gowns. Everyone gets up.

The ‘advocates of the trees’, lawyers Jan van de Venis and Jessica den Outer, call on the public to empathize with the trees. For most attendees, this is probably not a new exercise in empathy. Books such as those by the German forester Peter Wohlleben have brought the lives of trees closer to home before. For example, Wohlleben spoke without hesitation about ‘family relationships’ between trees, about ‘mother trees’ who ‘breastfeed’ their ‘children’ and share food with their families, about how trees ‘talk’ to each other through their roots and fungal networks underground, the so-called Wood Wide Web demonstrated by Canadian professor Suzanne Simard.

The lawyers ask the public to consider that the trees of the Amstelpark are actually still ‘children’. Their life expectancy is between 200 and 400 years; this means an age of 50 years is still very young. ‘What childhood have we given these trees? A screwed-up youth’ Van de Venis quotes from an article in Het Parool: ‘House plants from Africa, wild plants from the Amazon region, large cacti from Mexico. Money was no problem… Thanks to the Floriade of 1972, for which the park was built from the ground’. Were the interests of those trees considered?

‘No older trees around to help them, no support, contact, and exchange underground and above ground with species that allow it to run smoothly. Alone, learning from each other and often surrounded by other – sometimes exotic – trees that they do not recognize from their natural system, with whom they have no natural interaction, whose signals and language they did not understand, they grew up’. This is what Jan van de Venis is telling us. Suddenly I picture insecure trees that have been torn from their natural habitat and have to find their way in a strange environment. Not to mention the air pollution, soil pollution, and climate change that the trees have been exposed to throughout their lives. Poor trees..




It, therefore, comes as a surprise when tree scientist Ute Sass-Klaassen later testifies as an expert, stating that most of the trees she examined in the Amstelpark are doing quite well. Trees generally turn out to be pretty tough guys. She and her team from Wageningen University’s Dendrolab sampled six tree species in the park. A dendrochronologist uses a kind of apple corer to take a sample from a tree trunk: from the bark to the center of the tree. You can tell from the rings of these cores how well a tree fared in a given year. In a good year, a tree produces broad rings, in a bad year (for example dry years such as 1976 and 2018)  annual rings are narrower. But how fast a tree grows also depends on the tree species and how much competition a tree has from other trees. For example, if a neighboring tree takes away a lot of light, a tree will grow slower and therefore produce less wood and narrower annual rings.

Due to seasonal changes, trees in our climate area form annual rings. The trees begin to grow rapidly in the spring and form large cells. In the summer they form increasingly smaller cells and grow slower until they stop growing in the fall. Due to the abrupt change from small to large cells, annual rings can be distinguished in the wood. Sass-Klaassen can clearly see that trees grow worse during drought, but she also sees that recovery is fairly quick once the precipitation returns. In the Amstelpark she saw that the Dutch elm, the Canadian poplar, and the sweet chestnut are doing reasonably well. And she doesn’t want to complain about the Douglas fir either.

The Norway spruce, however, is a ‘worry child’, says Sass-Klaassen with a charming German accent. Those trees have clearly been weakened by the drought of 2018 and 2019 and therefore bark beetles reigned freely. This applies to Norway spruces throughout Central and Northern Europe. Thousands of hectares of Norway spruce are now dead. ‘The insect pressure is very high.’ Earlier, Sass-Klaassen told me that the situation of the Norway spruce is currently leading to a ‘panic in forestry’. ‘After all, a large part of the European timber market revolves around Norway spruce. Now we have to look for an alternative.’

To investigate the extremely dry year of 2022, the Dendrolab was obviously not able to look at the rings yet – these hadn’t been formed yet. That is why Sass-Klaassen used sensors that measure the invisible movement of the trunks from the outside. Trunks contract during the day because they lose water through evaporation through the leaves. During the night, the tree absorbs water from the soil again through the roots and then the trunk expands. These are tiny movements of the trunk, not perceptible to the naked eye, but measurable with the sensor. This daily rhythmic movement is also known as the ‘heartbeat of the tree’. ‘In the summer of 2022, we saw with the sensors that the trees reacted strongly to the enormous precipitation deficit in August, but that they also recovered somewhat at the end of August, when the rain came.’ Sass-Klaassen explains that trees are extremely flexible. ‘Otherwise, they would never be able to live that long.’

However, there is a limit to that flexibility. Too much heat, too much drought, soil acidification due to nitrogen deposition, and air pollution. ‘It’s one, one, one. We have come to the point that ‘nature’ can no longer take care of it all on its own. It’s not hopeless, but action is needed.’




The question is what form that action should take. The call to empathize with the tree, that anthropomorphizing call for empathy, may awaken people who have never delved into trees before. A tree with a heartbeat and a terrible youth who talks to his family via the wood wide web: a tree like this captures your attention more than a handbook full of Latin tree names.

Yet at the same time, the ‘humanization’ of trees fills me with a certain discomfort, especially if it goes beyond artistic expression and has legal implications by claiming rights for nature. In Other Lands, the phenomenal science journalism work by the British Alex Halliday, I read about the history of the earth, the ‘house of millions of years’. Australopithecus ansmensis, which also includes the famous Lucy fossil, descends from the first hominids to appear 3.2 million years ago in Kanapoi (the African Somali Plate). The trees descend from algae via different lines and arose much earlier. During the so-called ‘Cambrian Explosion’, the explosion of life 500 million years ago, the first seeds were laid through algae and mosses for trees to eventually develop during the ‘crushing humidity and invigorating heat’ of the Carboniferous (350-300 million years ago) and more or less dominate the earth. Halliday describes how high-density tree root systems (26,000 roots per square meter) not only kept trunks together and anchored to each other but also how these ‘root plates’’ changed the soil itself. ‘Roots transform landscapes because they initiate other processes in the soil’. In fact, there is no soil without roots. ‘Digging root systems pulverize sand, retain humus, and change the chemical composition of the atmosphere. Roots determine the course of rivers.’ In this way, trees created the earth on which humans could eventually live.

Tree roots created our home and tree leaves allow us to breathe by making oxygen from the light of the sun. The role of trees in the ‘house of millions of years’ is so powerful and awe-inspiring that I fail to see trees as vulnerable beings to whom we would grant rights. I see a big forest where the trees laugh together, chuckling in their gnarly fists: ‘You? Seriously? You give us rights? haha! Don’t worry about us. We’ll survive. Rather worry about yourself…’ This too is humanization again, I know.

Trees have survived previous waves of extinction on Earth, but whether humans will be able to do so remains to be seen. We need them more than they need us. Protecting trees is perhaps primarily a matter of well-understood self-interest. When I asked the late Christopher Stone in 2016 about the impact of ‘Should trees have standing?’, he concluded that the environmental movement had achieved a lot in a legal sense with proceedings based indirectly on human rights and not on direct rights of nature. In this way, regulations for the protection of the environment and nature may paradoxically mean that legal personality is less likely to be granted to non-human entities such as trees.




The lawyers of the speculative trial in the Amstelpark therefore explicitly refer to human rights, enshrined in international treaties. They refer to the ‘fast-growing and global trend where more than 37 countries have already enshrined the concept of Rights for Nature in laws and regulations and more than 409 worldwide initiatives advocating the recognition of rights for Nature, of general rights for Mother Earth.’ rights of specific natural areas or animals. The question is whether all these weighty and important cases are best served by standing up for ‘rights of trees’ or whether it would perhaps be more helpful to enforce ‘the duties of the people’ in an entirely human-shaped legal system.

Peter Akkerman, chairman of The Forest That Owns Itself, founded by young people, speaks of the foundation’s goal of nature with self-government. Although humans are still welcome in the forest, this foundation does not want ‘ideal habitat types into which the forest is subsequently transformed’, Akkerman says. Instead, we want to look at the life that is already there and see how we can support it.’ They started with a piece of forest near Soest (NL) that has been returned to nature ‘forever’.

Akkerman puts his finger on the sore spot. Absolute property rights are a cornerstone of the Western legal system and of the capitalist system in which we live. Many indigenous peoples do not have such a form of property rights. The ground gives and the ground takes. There are systems of interdependencies that are far removed from the pyramidal structure of absolute ownership and rights derived from it such as usufruct, rent, or pledge.

This perspective on the world cannot be reconciled with the system of interdependencies that together make up a forest. Just as in quantum mechanics matter dissolves in mutual relations at the smallest imaginable level, an ecosystem cannot be divided into separate property relations. An ecosystem such as a forest consists of a large web of mutual relationships that together are greater than the sum of its parts.

Why would we squeeze trees into that human mold of ‘rights’? The system of property and individual rights is a concept of western colonial mankind. This is the person who messed up and this is the person who must be held accountable. Isn’t it better to focus on the duties of this human being than to try to artificially fit trees into the mold of the Western ruler?




In the National Museum of Antiquities in Leiden I stand before a thick, round disc of cedar wood from Lebanon, overcome by a pleasant smell, a seductive mixture of conifer, honey, and tobacco. Sweet and sticky sap glistens on the yellow-orange wood slice. Dr. Tania Zaven, regional director of the North Mount Lebanon/Byblos archaeological site, is delighted with the wood: ‘The cedar tree is Lebanon’s national pride and is even depicted on the flag. If you cut a cedar tree in Lebanon, you will go to prison.’ The chance was therefore small that she would be able to obtain cedar wood for the exhibition in Leiden. Most cedar trees in Lebanon have been felled and the trees that remain are intensively protected. Until a few months ago a violent storm broke out. Zaven, who lives next door to the Byblos archaeological site, saw that a large cedar tree had been felled in a neighbor’s yard and immediately asked them if they would like to donate a piece of the wood for the exhibition.

The cedar wood forms the fitting conclusion to the impressive exhibition Byblos: the world’s oldest port city. Wealth, trade, and civilization from the early Bronze Age: everything in Byblos started with the prestigious wood of the cedar trees, which were cut in the forest around Byblos and easily transported by river and sea. The wood was sturdy and the trunks could grow up to forty meters in length, particularly suitable for making boats. The Egyptian pharaohs had their sarcophagi made from the sought-after cedar wood, but cedar resin was also used as glue and preservative, for mummification and the sealing of wine jars.

The sea route between Egypt and Byblos was already in use at the end of the fourth millennium BC. Because ships carried more than just logs, this is how Byblos quickly became an important seaport.

There are different versions of the Babylonian poem the ‘Epic of Gilgamesh’, I read in the public book accompanying the exhibition, written by David Kertai with contributions by Jonah Lendering. In all versions, the cedar forest plays an important role. Gilgamesh, king of the Mesopotamian city of Uruk, goes with his wild friend Enkidu, to cut down cedar trees. Before that, however, they must first kill Huwawa, the guardian of the cedars. ‘After a fierce battle, they sail with the timber across the Euphrates back to Uruk. There Gilgamesh attracts the attention of the goddess Ishtar, but he rejects her. She takes revenge by sending the Bull of Heaven to Earth, but the two heroes also kill this monster’, the authors of the book accompanying the exhibition, write. Because Huwawa and the Bull of Heaven were divine, Gilgamesh’s friend Enkidu is afflicted with a deadly disease as punishment. Gilgamesh falls into deep mourning and sets out in search of the secret of immortality. Only when he finds out that he too, king of Uruk, will have to die, does he accept this truth, and he returns to Uruk a wiser man and a better king.

Robert Macfarlane recently wrote in the New York Review of Books about the latest translation of Gilgamesh’s epic. The episode about the cedar forest is actually ‘an epic within the epic’. He writes that it meets the literary genre’s conditions with a challenging journey that allows the hero to prove his strength. Historically, it was a military raid on the woody springs of a neighboring empire.’ But Macfarlane also believes that there are ‘strong indications that the episode about the cedar forest is intended as a parable of exploitation of the environment.’ Translator Sophus Helle describes the lush, living forest in detail and contrasts it with the ‘flatly leveled wasteland’ before concluding that ‘the Babylonian literature comes closest to an ecological critique here.’

Amitav Ghosh provides the same ecological criticism in his recent book The Nutmeg’s curse: parables for a planet in crisis. In 1621, Jan Pieterszoon Coen led a fleet to the Banda Islands, a Moluccan archipelago known for the rare nutmeg tree. The VOC virtually exterminated the native population for its own lucrative spice trade. Ghosh not only criticizes the violent, ‘VOC mentality’ that inexorably links trade with war but also emphasizes the way in which colonialism and depletion of the earth are intrinsically intertwined. Here, the nutmeg tree is more than a metaphor: genocide and ecocide stem from the same source.

Of course, the designers of the Amstelpark did not kill people, cut forests, or exploit any overseas land, but the way the park is composed, as a kind of colonial ‘Wunderkammer’ of exotic plants and trees, stems from the same attitude towards nature.




Recently, the Markiezen oak of the Amelisweerd estate was voted ‘tree of the year’. ‘Oaks are always very popular’, says Ute Sass-Klaassen, ‘this Markiezen oak winning is a clear signal from the community that they do not agree with the felling of parts of the forest of Amelisweerd for the expansion of the A27 highway’.

But as well-intentioned as such elections may be, electing an individual tree as ‘tree of the year’ says more about the current human age in which we live than it does about the trees that are elected. We live in a time in which trees compete with each other individually and where we obsessively judge the world around us and try to sum it up in the top five lists of the most beautiful, the best, and the best smartest. A time in which we prioritize individual achievements, rights, and interests, and overlook collective intelligence, cooperation, and interdependencies. Collectives and group rights of larger, emergent entities such as a forest do not fit well in Western legal systems. In the Western legal system, after all, the individual and his property are central.

Sass-Klaassen tells me that it is important to look at the forest, at the entire ecosystem. Trees also die there. But people don’t like looking at dead trees. In addition, in most Dutch forests, young – mainly deciduous trees, the ones we so badly want to make our forests more diverse, do not stand a chance, because wild boars and deer eat everything. But people like deer, so we let this happen.’ She believes that cutting down trees for timber harvesting is not problematic if it is done in a sustainable way. ‘If we want to use renewable materials instead of steel, plastic, and cement, we will also have to look at the production function of forests.’

In the book How Forests Think (2013), anthropologist Eduardo Kohn questions the basic principles of our understanding of humanity. Kohn spent four years doing field research with the Runa, an indigenous group of people in the Amazon region of Ecuador. He not only examined, as is customary in traditional anthropology, the way in which these people give meaning to the world around them. He also tried to understand how the environment itself gives meaning to people, and how there is a reciprocal process. He wonders how the jungle thinks, how dogs dream, and how the jaguar sees us. ‘How other organisms see us matters. The fact that other organisms see us changes us.’

Kohn calls it ‘anthropology beyond mankind’ and wants to contribute to the post-humanist critique of our Western perception of man as an exceptional being, as being superior to all other forms of life. In doing so, we have shut ourselves off from the world around us. We study the world through our human forms of meaning, such as language, culture, and history. ‘The object of analysis, mankind, thus takes on the same human form as the analysis itself,’ writes Kohn. ‘But this way we can’t see how we as humans are connected in many ways to a wider world of life.’

That is why, according to Kohn, it is so important that we develop an ethnography that extends beyond humans. That means, among other things, that we have to learn to think beyond language, which makes this kind of research chaotic and confusing for many Western people. We need a broader umbrella for our thinking and being, but can we think beyond ourselves, or are we trapped within the boundaries of our human language and culture?

With his project, Elmo Vermijs has attempted to investigate how people and trees give each other meaning. It is special that he himself explicitly stepped aside and made room for a collaborating collective of artists, lawyers, judges, and scientists. Before the meeting started, everyone was introduced to each other, even the trees. We stood in the circle and Vermijs asked for a moment of silence to be with each other and with the trees. Connecting the arts, science, law, and policy; this is the beginning of what Eduardo Kohn advocates, the beginning of a different way of being human, the beginning of learning to understand ‘how a forest thinks’.



This essay was published in the Groene Amsterdammer on Feb. 1, 2023