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The ‘wood wide web’ theory charmed us all – but now it’s the subject of a bitter fight among scientists | Sophie Yeo
Environment Science

The ‘wood wide web’ theory charmed us all – but now it’s the subject of a bitter fight among scientists | Sophie Yeo

You have probably heard the theory, that the health of forests depends on common mycorrhizal networks. Trees send resources to their neighbours through strands of hyphae, which act as an underground arboreal postal service, connecting root systems within the soil. Mature trees preferentially provide their offspring with resources, ensuring the survival of their own.

Not ringing any bells? Try switching “common mycorrhizal network” with “wood wide web”, the more familiar term that has described this phenomenon in hundreds of more mainstream places: novels, magazines, films and television series. The wood wide web is one of those rare things – a scientific theory that has captured the popular imagination.

The explosion of interest comes not from an unaccountable passion for fungal networks but for what the theory implies: that the natural world is not static and cruel, but rather a living community governed by the same moral principles as our own.

The concept of the wood wide web originated in a series of scientific papers led by the forest ecologist Suzanne Simard. Her 2021 book, Finding the Mother Tree, cemented the hypothesis as a global phenomenon. No one can blame an academic for framing their work in terms the layperson can understand, even if some precision is lost along the way. But trouble arises when a scientific theory gains a life of its own, becoming culturally relevant in a way that ignores, simplifies, or contradicts the facts that birthed it.

This is what has happened in the case of the wood wide web. In 2023, three scientists, led by Justine Karst at the University of Alberta, published a paper in the journal Nature Ecology & Evolution arguing that the wood wide web theory had gone too far. Their language was measured: it was not that these mycorrhizal networks didn’t exist, they said, but rather that the claims about what they did outstripped the evidence. More research was needed.

Simard did not take the criticism well. Their paper, she responded, was “an injustice to the whole world”. In an article published in Nature last month, she accused Karst of a conflict of interest because she had taken funding from Canada’s Oil Sands Innovation Alliance – the implication being that her comments were financially rather than scientifically motivated.

Karst then hit back at these claims, both in the article and later on X. “This was an attack made in bad faith to demean my character and question my objectivity,” she wrote. “Behind the scenes of the ‘debate’ has been ugly. It might get worse and I could spend more time defending my character than debating the evidence. I hope you understand that I can only lose in this situation. So, I’m out. Debate without me.”

We think of science as neutral: experiments unfolding neatly, numbers noted on spreadsheets, society advancing in increments towards an absolute truth. Scientists are the automatons behind this process – temporarily able to transcend the biases, beliefs and subjectivity that make everyday life so complicated for the rest of us.

But that could not be further from the truth. Scientists are not superhuman – they, too, form attachments. Indeed, in their original article, Karst et al did not blame Simard alone for the runaway success of the wood wide web. Other scientists had also exaggerated the evidence, they wrote, citing papers in support of the hypothesis, even when the actual papers were lukewarm on the idea. No wonder so many journalists had seized on the metaphor: not only was it emotionally appealing, it also seemed incontrovertibly true. As a result, the speed at which the idea had spread through the public realm had outpaced the science underpinning the idea itself.

The wood wide web is among many instances of scientific ideas going rogue. I have spent the last three years writing a book on environmental history – a subject particularly prone to myth and misrepresentation. I usually found that simplicity and romance won out over complexity and nuance. Repetition easily supplanted reality; when enough voices sing in unison, few stop to question whether the words are true.

One of the many myths I encountered during my research was the Great Wood of Caledon; that is, the notion that the Highlands were once covered in a great pinewood – until humans cut it down. Indeed, the central tenets of the myth are often repeated in the media and by politicians.

However, contrary to the popular understanding, palaeoecological evidence suggests that prehistoric climate change played a large part in the demise of these forests. The reality is more complex and less politically appealing than the oft-repeated myth. But we should not fear difficult ideas.

I like simplicity and romance, but I also like accuracy and open-minded debate. Scotland has fewer pinewoods than it could; the past doesn’t change that. Meanwhile, scientists continue to work quietly to untangle the many mysteries of mycorrhizae. How widespread are these networks in forests? Do they really benefit seedlings? Can mature trees actually support their kin? Let us hope that the wood wide web is flexible enough to incorporate such progress as it happens. As Karst herself put it: “Less hype. More hyphae.”

Science thrives on debate. When people become wedded to a particular idea, that debate can get personal. Opponents are no longer challenging a hypothesis but a worldview, one that many people beyond science have become attached to. We owe it to the planet – and to each other – to stay open to the truth.

  • Sophie Yeo is editor of Inkcap Journal and the author of Nature’s Ghosts: The world we lost and how to bring it back

Source: theguardian.com