To ensure human longevity, let nature replenish the forest.

The autumn forest is a funfair of curiosities. Every fungal fruiting body is a standing surprise, endowed with molecules that reveal a knowledge no less than extraordinary.

For hundreds of years, the kingdom of fungi has been overlooked as a minor or even odious aspect of nature, compared to the kingdom of trees and flowering plants. The digital generation is now discovering that fungi are fascinating. The corridors of exploration run deep in human consciousness, through fields and woodlands, connecting all lifeforms across the land. People are captivated. These eukaryotic organisms, which include microscopic yeasts and moulds as well as mushrooms, play a herculean role underground in supporting all terrestrial life.

While an appreciation of fungi’s important environmental role is becoming widespread, an area less celebrated is how they contribute to medicine, and in supporting health and wellbeing more generally.

Fungi are responsible for some of the most important medicines of the modern age. Scientific medicine harnesses fungal species in various ways to target human pathogens and illness. Powerful antibiotic, anti-parasitic, and anti-cancer drugs have been discovered from fungal compounds in recent years; this means we no longer need to die from common infections that, not even one hundred years ago, would have sent our forebears swiftly to their graves.

Medicinal mushrooms are another type of medicine — distinct from the synthetic drugs mentioned above, including penicillin — whereby crude mushroom material is consumed either fresh or dried for its healing effects. This class of medicine is understood not in the context of pharmaceutical drugs, but as health supplements which boast up to 130 medicinal functions, from anti-tumour and antioxidant to antiviral, anti-parasitic, and many others. Among these species are tree fungi such as reishi, turkey tail and chaga, perhaps too woody in texture to enjoy in a risotto. Other species are fragrant and edible such as shiitake and enoki that feature in many recipes.

Birch polypore is a type of medicinal tree fungus which grows almost exclusively on birch trees in the northern hemisphere. Termed ‘nature’s first aid kit’ for its impressive range of medicinal uses, this is one species that more people should get to know and appreciate.

Since as far back in time as the Neolithic Age, Birch polypore has a unique history of being used in sophisticated ways by Europeans. Yet the way forests are now commodified, which prioritises yield and productivity over allowing diverse species to flourish, this remarkable tree fungus, and all healing forest species alike, will become an increasingly rare sight.

Throughout autumn and winter, varieties of rubbery and woody conks burst from the bark of decaying trees. Tree fungi, also called bracket fungi or polypore, are especially peculiar. These are stores of biochemicals that primarily destroy life, but can also restore it. In the forest ecosystem they are the chief agents of wood decay, which is classified into brown rot, white rot and soft rot. Each type of rot has a different way of consuming dead wood.

Brown rot causes the wood to harden, darken and fracture into cubic pieces. Chicken of the woods, Lactiporus sulphureus, a forager’s favourite, and birch polypore, Fomes betulinas, are two examples. Honey mushroom, tinder punk, artist’s conk and turkey tail cause white rot which turns the wood a soft stringy and spongy texture.

All broadleaf trees in the northern hemisphere are susceptible to tree fungi. Some species aren’t fussy about which kind of tree they live on. Shaggy bracket (Inonotus hispidus), for instance, will happily feed on ash, plane, walnut and apple trees. Birch polypore, on the other hand, is only ever found on birch trees.

In the English countryside, deciduous woodland has been disappearing rapidly over the past two hundred years. Forests rich in medicinal tree fungi are becoming harder to find. The remaining ancient woods are patchy, small and threatened by construction works, new roads, railways and housing schemes.

Throughout the 20th century more than half of woodland has been replaced with a monoculture of Sitka spruce: a strictly managed economic crop, now making up a majority of the public access forest in Britain and Ireland. These plantations are called Forestry Management Units (FMUs). Here, trees aren’t allowed to grow as trees do, but as branchless stands, and their straightness is the single most important commercial quality. They don’t reach old age, as they are felled for timber when they are fifteen years old.

The book Seeing Like a State by anthropologist James C. Scott offers a way of understanding how we came to shape our world at odds with nature, and indeed our own sensibilities. ‘Fiscal forestry’ is the process he refers to as ‘the simplification, or narrowing of vision, that brings into sharp focus certain limited aspects of an otherwise far more complex reality’. This way of seeing has greatly reduced the number of different species we encounter in woodlands.

In the plantations the neat, geometric rows of branchless conifers only make sense when viewed through a utilitarian lens, whereby ‘the actual tree with its vast number of possible uses is replaced by an abstract tree representing a volume of lumber or firewood.’ Entirely absent are the natural vegetation, shrubs and creeping ground plants.

At the frayed edges of the plantation, bordering the farmland, the control of forestry management tapers off and nature silently restores unauthorised relationships. It was here I spotted four perfectly formed birch polypore conks high up on a hedgerow tree overlooking a livestock field. Not quite believing my eyes, I climbed up to get a closer look.

The dome shaped tops were smooth and flawless; the colour of frothy cappuccino and milk. They smelled cloying and antibacterial, like chlorine. I’m not much of a forager; because who am I to pluck a living thing from its earth bed and interrupt a sacred conversation? But that afternoon I returned home with three trophy conks I had torn from the bark.

A Neolithic ‘iceman’, whose mummified body had been recovered from a melting glacier in the Italian Alps, had been preserved in a frozen state for over 5,300 years. He was found with two ‘walnut-sized’ pieces of birch polypore threaded to a leather thong with decorative tassels. Researchers believe he was suffering from intestinal parasites known as whipworm, and was ‘fighting them with measured doses’ of birch polypore.

You might imagine what would happen if researchers 5,000 years in our future found the mummified remains of a person alive today, who had died on their way home carrying medicine from their local chemist. By analysing the mummy and the prescription, they could draw fascinating inferences about our healthcare system and state of health — and even deep misunderstandings.

When the Neolithic age began around 12,000 years ago with the birth of agriculture, forests were  pharmacies. Ancient people who lived in these forests had intimate knowledge of its fungal fruits and how to use them. Archaeological digs of settlements, unconnected to the Iceman discovery, have come up time and again with remnants of polypore species, indicating tree fungi were precious resources that played a role in human survival.

The popular mycologist Paul Stamets writes in a journal article ‘although mushrooms have long been used by various cultures, only recently has modern science rediscovered what the ancients knew long ago — that mushrooms can be deep reservoirs of powerful medicines.’

Indeed, only recently has science confirmed birch polypore to be a powerful anti-inflammatory, anti-cancer, anti-fungal and anti-bacterial agent. Some of its bioactive extracts have contributed to new and important medicines: Piptamine is an antibiotic that treats e coli infection and Betulinic acid is used in various medicines, notably to treat cancer and malaria — it also kills whipworm (Trichuris trichiura), the parasite found in the Iceman’s intestines.

From Siberia to Scandinavia, and across the northern hemisphere, birch polypore is one of the oldest known natural remedies. According to sources, it was used by Russian peasants to cure tumours. From the Iceman’s story we know hunter-gatherers in the alpine countries deemed it valuable enough to carry carefully on medicine strings. Birch polypore knowledge, however, belongs to a non-written system of ancient medicine which is altogether lost to us.

I boiled a few slices of the special fungus in a pan, watching the resins and oils leach out and swirl in the water. The tea tasted bitter, but gave me no ill effects. Three large polypore fruits, sliced and dried, provided around three months of health tonic. I wanted to know how to use it: should I drink it every day like taking a course of vitamins, or just a cup now and then when I was feeling run down? It seemed a bit unfair that for the entire town there was only one tree in the local forestry unit that produced this medicine. Perhaps someone else needed it more than I did? I split the harvest with a friend who suspected she might have ‘long Covid’. She later told me that it helped her to recover.

Birch fungus is common in British and Irish woodlands — but deciduous woodlands are not, which makes the solitary example in my local forestry unit even more poignant. The opportunity to find, forage and use these fungal medicines to support health has been greatly diminished by scientific forestry.

Our severance from nature entailed a loss of general knowledge about local plants and fungi. Those who enjoy the outdoors and seek out its wonders will no doubt come up against the boundaries between science and romance which put a psychological limit on access to, immersion within, and exploration of nature. The amateur feels self-consciousness identifying plants or fungi, the domain of the trained botanist or mycologist.

To recommend a natural remedy that worked for you, you ought to have a diploma in herbalism. By showing an interest in medicinal mushrooms, you’ll risk being taken to task by riders of the science stallion telling you there is no evidence for their effectiveness outside the lab.

Wherever you venture in nature, you’ll find the controlling hand of one science or another.

By definition, folk medicine is ‘the sum total of knowledge of all healing practices and beliefs about the causes and treatments of illness’ in the premodern world. The term loosely represents an unsystematic, unofficial and unverifiable jumble of superstition and belief. This is, perhaps, the total of everything science has been systematically eliminating since the 17th century, when Francis Bacon formulated the precursor to the scientific method.

Tasked with dispelling ignorance and building reality upon official knowledge, science has assumed an absolute monopoly on truth. But in following this rigorous process of elimination, might we have committed an avoidable error in rejecting the favourable along with the unfavourable?

In the ancient world, knowledge of medicine was localised, general and ecological. It was important to observe a species in its natural context and understand its relationships in order to make correct assumptions about its identity and uses. For the hunter gatherer, this knowledge was essential: a matter of life and death. Of two species that look similar, one could cure and the other could kill.

Indigenous cultures in modern times have retained this system and some of this knowledge is still alive. However, common knowledge of how to use local plants medicinally has almost completely disappeared in many industrialised countries.

Plant and fungal medicine is as old as human existence. It is an ancient part of human culture and way of seeing in nature that arose in Africa between 100,000 to 200,000 years ago; a way of solving complex problems of survival in a dangerous environment that daily foreshadows disease, injury and death.

Jing-Ke Weng, professor of plant biology at the MIT, describes how the ancient knowledge system of Traditional Chinese Medicine (TCM) is not incompatible with modern, evidence-based medicine.

“Just like the rise of chemo diversity in plants which is entirely a trial-and-error process, our encounter with medicinal plants is also a trial-and-error process, based on thousands of years of experiments on human subjects”, he explains in a documentary.

Weng describes an ancient process of discovery which is systematic and based on empirical evidence. In the ancient world these experiments took place over an extremely long period in time. Plants and fungi that have remained in the TCM canon for thousands of years have done so precisely because they've proven themselves effective time and time again.

Traditional medicine ends where modern science begins: it is the task of science to remove a species from its natural context in order to study it in vitro, in isolation from its natural context. The process of drug discovery breaks down a species into its constituent parts to determine the precise effects these have on living tissue. In the laboratory, relationships are removed and complexity is stripped away, bringing the active molecules into sharp relief. By the time the molecules have been synthesised, they are far removed from their origins in nature. Pharmaceutical drugs are given long, illegible names which convey information about the chemical structure of the ingredient.

Scientific specialisation entails a ‘narrowing of vision’ which often fails to see a bigger picture. Healthcare was once bound up with an intimate knowledge of plants and fungi, and, therefore, entailed a deep human sympathy with the environment. Advances in modern science mean we now enjoy much longer average lifespans and experience less of the physical pain and suffering that plagued our ancestors.

Yet, over millennia, our predecessors were able to deliver the human race safely to the 17th century, despite relying on plant medicines and being ignorant of bacterial and viral causes of disease. Their success strongly suggests they had a sophisticated system of knowledge, built on reasoning and testing and verifying information.

Our modern world, built on skyscrapers of facts, facts, and more facts, has produced a reality where comfort and abundance come easy, as long we keep heading in the same linear direction. But the foundations are thin and the system creaks, without the informal networks and natural associations that could otherwise provide support. This ‘separation of knowledge’ between medicinal plants and ecological knowledge reveals just how vulnerable humankind has become: to the ravages of environmental erosion and armies of viruses gaining resistance to our modern medicines, which mutate and grow with each passing day.

Prioritising forests as sacred places of wisdom, knowledge and healing, by allowing nature to restore and replenish its unofficial relationships, would surely assist the longevity of the human species.

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