Until recently, fungi have been a relatively  neglected area of study, but as Merlin Sheldrake’s recent book, Entangled Life, [1] reveals, the fungal world is as vast, varied and complex as the realms of plants and animals which have been the object of human investigation since antiquity. Combining the latest scientific research – the field is called ‘mycology’ – with stories of personal experience and a vivid style of writing, Entangled Life is an accessible and comprehesive introduction to a subject which seems to have particular relevance to us today. Isabella Tree – of Wilding fame [2] – has said that it ‘changes the way we need to look at life, the planet and ourselves’ and it does, indeed, seem that almost every page reveals some new, hitherto unsuspected wonder.

Fungi do not fit in to our traditional classification of things as animal, vegetable or mineral. They lie somewhere between plants and animals, and as Merlin points out, there is no university department devoted specifically to them. Before the burgeoning interest of the last few decades, many aspects of fungal life were largely invisible and their properties unknown; of the estimated 2.2 to 3.8 million species, 90 per cent are still undocumented. We began by asking him what he thinks  has brought them into view now.

“I think there are a number of reasons, some of them quite simple. One is that we now have technologies that we simply did not have a few decades ago, like DNA sequencing, which enables us to take a pinch of soil and work out all the organisms that are present in it. So increased access to microbial and fungal lives allows us to ask more questions and satisfy our curiosity about them in new ways. We see a similar explosion of interest in other types of microbe, like bacteria, for the same reasons.

“There are other factors. Fungi live their lives as networks – known as mycelium. In recent decades network thinking has risen to prominence within many disciplines of human study. This has been driven in part by the Internet and the digital networks that we are now all familiar with, but network models are also now used, for example, in biology, where parts of cells are understood to be strung together in networks of interaction.

“Yet another reason is that there has been lots of work on the properties of the psychedelic compound psilocybin, produced by a number of species of ‘magic’ mushrooms. Psilocybin has shown great promise in treating conditions ranging from depression to addiction. There is a huge amount of research into the subject going on now, and it has already led to psilocybin mushrooms being decriminalised in several US states.”

Hidden Networks

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When most of us think of fungi we think of mushrooms, but these are only the fruits of the much larger mycelium which are hidden from view. These sprawling web-like structures can be huge: one honey fungus in Oregon spreads over ten kilometres, weighs hundreds of tons, and is estimated to be between 2,000 and 8,000 years old. And they are ubiquitous: the mycelium in a teaspoon of soil, Merlin tells us in the book, would stretch from one to ten metres if they were teased out. It seems amazing, we comment, that we have been living in such intimate contact with these life forms all the time, and yet we have been almost completely unaware that they are there.

“The question of visibility was a big challenge in writing the book. Fungi have long been known to us as things like mushrooms, or in the form of alcoholic drinks or bread. But when we are talking about mycelium living in the soil, our senses can only take us so far. So I had to think carefully about how to write about them in a way that would allow people to relate to them. I had to use metaphors and stories to make them more accessible and to engage people’s imaginations.”

The most obvious metaphor, as we have already mentioned, is that of the Internet. Does he think that this paved the way for this new understanding? Merlin thinks it is not so simple. “The understanding of biological networks and computer networks have really developed in parallel, rather than one leading to another. It was in the late 1990s that the term ‘the wood wide web’ was coined, just at the time when the Internet was coming into being and the World Wide Web was being mapped. But much of the early research was going on in the ’80s. Without doubt, though, ‘network thinking’ has made it possible to conceive of this kind of system, where resources are distributed and shared.”

But there are many other images and metaphors which Merlin employs. In describing how the multiple growing tips of a fungus (called hyphae) act – at one level, in a seemingly independent way but at another the whole body acts as a single entity – he makes an analogy with swarms of insects or schools of fish. In these, the members act as a collective even though, as in fungi, there is no central command centre. However, he points out that mycelium quickly outgrow the swarm analogy. “Because all the hyphal tips in a network are connected to one another… one cannot dismantle a mycelial network hypha by hypha once it is grown as we could pick apart a swarm of termites.” [3] Fungi therefore exhibit an even higher – and more mysterious – degree of interconnectivity than we see in the animal world.

In other places, he uses physiological imagery. Referring to the use of layered diagrams to describe the structure of the body in textbooks – one layer for organs, one for bones, one for the nervous system, etc. – he imagines that if we were to draw the same sort of diagram for the earth’s biological systems, the vast networks of mycelium would have a whole layer to themselves. He calls them ‘ecological connective tissue’, and ‘the living seam by which much of the world is stitched into relation’.[4]

But he is also aware that these metaphors can restrict our understanding of what is, in the end, a life form which is very different from anything else we know. “We lose something when we use the analogy with, say, digital networks to understand mycelium, because actually they are not made up of cables and routers; they are living organisms. So when we talk about the ‘wood wide web’ there is a danger of mechanising it.”

Unusually perhaps for a scientist, Merlin is not only interested in what we can learn about fungi. He also wants to think about what they can teach us: “We tend to make analogies using human ideas, human systems, which we project onto ecosystems. But we don’t have to do this. Instead, we could try to think ‘outside the skull’ and let the ecosystems themselves become metaphors for human life. We could allow them to be what they are, and let them populate our imaginations with useful analogies of how to make sense of ourselves.”

Interconnectedness

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The term ‘wood wide web’ refers to the discovery in the ’80s of the extensive symbiotic relationship between trees and fungi in forests. ‘Symbiotic’ means literally ‘living together’, and biologically, refers to a collaboration between different species which is mutually beneficial. The fungi enable individual trees to draw nutrients and resources from the soil and to share them with other trees, in a sense communicating with them. In return, the trees provide fungi with the nutrition and resources they need to thrive (for more, see video right or below).

This degree of cooperation means that it is hard to say where one species begins and the other ends, challenging the idea that the world is made up of individual beings that operate independently. Merlin agrees: “We really like stories where we are isolated individuals who can go about our lives doing as we wish. It is this type of individualist narrative that helps to justify the environmental destruction and degradation that we are wreaking on the planet: if we really understood that everything is interconnected, we would see that by destroying the ecosystems that sustain us we are ultimately harming ourselves, and that it is irrational and unjustifiable. And of course, it is irrational and unjustifiable but we live within powerful narratives about independence and autonomy which help us forget this.”

It also rather changes our understanding of the way things develop and grow. When we consider the relationship between plants and fungi, did fungi help plants to evolve or is it the other way round? Merlin thinks that it is probably both. “If you look at 400 million year old fossilised roots you can see fungi living inside them and they look just like the ones that we see today. Plants, on the other hand, have changed quite a lot over this time.

“Of course, there have also been huge innovations in the fungal world – the appearance of mushrooms, for instance, to help the spread of spores – but the basic mycelial lifestyle seems to have existed for a very long time and there is not much that can be improved on. You could perhaps say that fungi hit the jackpot early on.

“But actually, we cannot really answer a question like this. It is a perfect example of the way that symbiosis forces us to think not in terms of individuals but of relationships. What we call plants are algae that have evolved into plants alongside fungi, so everything we see in the plant world is the outcome of an association. It is all a two-way process.”

Immersion in the World

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Symbiosis also makes us think in non-hierarchical ways. In the book, Merlin points out that when thinking of the wood wide web, for instance, we tend to consider primarily the benefit to trees as the ‘higher’ – and therefore, we assume, dominant – organism, but certain phenomena can only be explained when we understand that this is a true partnership in which conditions are also optimised for the fungi.

Our tendency to see hierarchies is most manifest when we think of ourselves as the pinnacle of evolution, the top of the pyramid. But Merlin would like to change this perspective. “I think it is interesting for us to pose questions like: where are we looking at the world from? Where are we positioning ourselves? I think we can do a lot of work to de-centre our privileged human placement by doing little things like asking: who is domesticating whom? If we keep asking this question, then the power – I should perhaps say, the assumed power – of the human becomes diluted. I think these lines of enquiry can bring us into a more honest and less destructive relationship with the living world.”

Thinking about our relationship with the world, it is noticeable that Merlin himself is a very hands-on sort of scientist, and immersion – often literally – in his subject matter is one of the striking features of his research as documented in Entangled Life. Chapter 7, for instance, begins with words: “I lay naked in a mound of decomposing wood chips and was buried up to my neck by the spadeful” – describing his sampling of a Japanese fermentation bath in California.[5] Is this a form of science that he thinks should be encouraged?

“Well I think it depends on what kind of person you are. This is really just a method that I like; I am interested in the way things work and can explore them more readily if I am in direct contact with my subjects. It opens up new pathways of enquiry for me...

The Living Foundation of Life

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Fungi have not just been pivotal to the evolution of life in the past: they continue to be central to its maintenance in the present. Could we say that they are the underpinning of the whole organic world? “Yes, you could say that, but the same is true for bacteria. In evolutionary terms, multi-cellular organisms and the whole hierarchy of the higher plants and animals are relatively recent. These microbes create the conditions for life, and continue to do so. You can think of them as a kind of living foundation.”

This understanding has enormous, important implications for the way that we understand the ecology of the planet. For plants to flourish, they need a good supply of nutrients and this requires them to form healthy relationships with mycorrhizal fungi in the soil. Therefore the fungi also need conditions in which they can flourish. All this adds up to the health of soil being of paramount importance. As Merlin explains: “Ever since human beings have started farming, around Neolithic times, the most important thing that we have had is the fertility of the soil. We have needed to think about what we put into the soil and how we are maintaining its fertility, because it is our bank – our capital – that produces the food that sustains us every year.

soil, a living collective

“When you think properly about the soil, and begin to see it as a living collective, then you can see that fungi play a lot of different roles in maintaining it. But the first step is to realise that we need to add carbon back into the soil – often in the form of vegetal mass. This might look like growing a crop and ploughing it back into the earth or by letting animals trample plant matter into the ground so that bulk is added to the soil, rather than it being reduced to a kind of mineral powder. When you harvest without putting mass back into the soil, then you are basically mining – mining the carbon, just as we remove coal from the earth.

“But if you put the carbon back, then you create conditions where these microbes can go about their lives. Then they will re-establish the mycelium webs by means of which the complex ecological and dynamical processes which characterise a healthy system can flourish.”

The problem with most of our current farming methods – and our forestry – is that not only do they not replenish the soil, but they also break it up so that the mycelium cannot do their work. As Merlin explains: “Modern industrial agriculture has developed without considering the life of the soil at all. More than this, one could say that it has developed without considering the life of humans who depend upon it. It is a massive, industrial corporate project which has its priorities in the wrong places, and it is leading us into a disastrous situation.”

So, is it hoped that this new knowledge about the interconnectedness of plants and fungi will lead to a change? “Yes, indeed. This is already happening in grassroots sustainable agriculture circles, where people have been thinking a lot about soil, and how fungi and microbes can not only be maintained in it, but also used to improve and nurture it. For instance, some people are working with old agricultural systems like the Korean system where they use compost ‘teas’ – liquid fertilisers – that you add to your plants and which also help the microbes within the soil.”

He goes on: “But I think that these ideas will also have an effect upon people within conventional agricultural circles as it becomes clear that our present unsustainable methods are going to have an impact within a very short time frame – in fact it is already happening; this is not in some distant future. I think that farmers will watch their soil turn to dust and blow away, and then it will be clear what the effect has been of all these chemical fertilisers produced by the big agri companies, and that our present system cannot go on without causing total disaster. So the movement for change is picking up speed for sure – let’s just hope that it is not too late!”