Trees communicating? Protecting their offspring? Sending warning signals? Even helping “competing” species? These are some of the incredible things we have heard about the “Wood Wide Web”. But, is it true? Or has the story got ahead of the science? A team of mycorrhizal researchers has discovered some painful truths about these fungal connections we have all come to be fascinated with. Justine Karst breaks down the myths and misconceptions about Common Mycorrhizal Networks (CMN), and the pain it caused her to do so. The first 50min is the science, the last 50min is the story behind it.
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Quotes
58.47 - 58.52: “If it makes you really mad, or if it makes you really happy, pause.”
1.00.49 - 1.00.55: “Distortion is distortion; whether you like where it goes or not, it needs to be called out”.
Takeaways
Early interest in mycorrhizal networks (5.22)
Justine grew up in interior British Columbia and spent her childhood exploring and loving the forest. However, she also experienced the fear of forest fires and thought deeply about the future of forests. Her dad was laid off from the local sawmill when it closed, forcing them to move. She studied ecology in her undergraduate program and forest ecology in her Master’s. She was fascinated by a paper showing carbon transfer possibly through a mycorrhizal network and begged the author, Melanie Jones, to let her complete her graduate studies with her.
The wood wide web (09.17)
Justine talks about how the belowground transfer of carbon in the field is not conclusively proven to occur through a mycorrhizal network, what some call the ‘wood wide web’. People have begun take notice of the wood wide web in the last 5 years. She defines a common mycorrhizal network as when roots of two different individual plants (could be different species) are physically connected by fungal tissue. Her research has focused on the mycorrhizal ecology of forests. She has also been involved in experiments testing the function of common mycorrhizal networks in forests.
Exploring the functions of mycorrhizal networks (14.43)
Justine discusses the types of fungi in the soil and the genotyping methods used on roots and fungi found in small slices of the soil to identify mycorrhizal networks. Only two studies in the world have done high-resolution sampling showing with high certainty that roots of different trees are linked by the same fungus. While there’s reason to think mycorrhizal networks are common in the soil, it’s not known the length of the connections and how long they persist, which creates doubt about their ability to move resources. Mycorrhizal fungi are very important in forests, but the function of their network is inconclusive.
What the world was thinking (21.03)
Justine was invited to interview for a documentary on mycorrhizal networks in forests. She was surprised by the speaking notes she was sent, which suggested concepts she has not heard of before. She reached out to Melanie to clarify her doubts, who mentioned that the study she was on often got miscited. Justine suggested she revisit why this was happening. Jason Hoeksema also contacted Justine as he had been observing the same. The three of them, having spent their careers in mycorrhizal ecology, began writing a paper together in 2021.
Debunking the myths (27.23)
The paper that Justine, Melanie and Jason worked on evaluated some of the widely held assumptions about mycorrhizal networks - that they are widespread in forests, their benefits to trees, and the communication of warning signals between trees through the mycorrhizal networks. Not enough studies have been done to conclusively support these ideas, and the methods used are difficult to control for confounding effects. Using different mycorrhizal types to trace their resource transfer in the soil works but there are issues making it difficult to quantify how much resources move through the soil rather than through the mycorrhizal network .
The truth about mycorrhizal research (42.10)
Justine, Melanie and Jason could not find any peer-reviewed, published field studies testing the claim that trees recognise their kin and send warning signals to them. One graduate thesis even proved those claims wrong. Justine, Melanie and Jason were saddened by the ongoings in the field but acknowledged how difficult it is to do field studies. When they looked at how scientists interpret these claims, they found that nearly 50% of the papers today citing original studies made unsupported statements.
“We’re looking to nature for how society should behave or act” (55.07)
Justine has found that the public loves the idea of trees cooperating with one another through “benevolent fungi”. She believes that emotions serve a purpose in our decision-making but they can also be easily manipulated by others. While she wants to see people rethink their connections with nature, she does not want science to be distorted towards that end. Because of the misinformation about common mycorrhizal networks, the difference between possibility and established fact has become blurry.
“I’d rather know the truth than believe in a fairytale” (1.05.45)
Justine acknowledges that her study may have burst the bubble for many but believes that the truth is helpful to all scientists. However, the lack of conclusive evidence on common mycorrhizal networks, in her opinion, does not devalue the conversations around species interactions. She highlights that since experts in the field are looked upon by the public in order to understand it, it is important that the claims they make are supported by evidence. She believes her job is to be critical but kind in shining a light on the misinformation and creating a way forward from it.
Common mycorrhizal networks 2.0 (1.13.12)
Justine, Melanie and Jason poured their personal time into completing this study, and are still passionate about the subject, despite the flak they may have received. However, Justine does get the rare message of support. Their study had three scientists sign the review, and their associating their reputation with the study was reassuring to her. The trio revised the manuscript based on their feedback and ensured it was thorough. Doing this work has taught her to critically engage with studies she comes across.
“Science has to recognize when it’s not invited” (1.27.35)
Justine recognizes that science sometimes may be in conflict with values and that it’s inappropriate to use science to attack values. However, it is essential to recognize that evidence is not part of discussion on values, so it is important to balance the facts-based current state against the values-based desired state. The dream of the wood wide web is an example of how science was distorted to legitimize a value due to positive bias in scientific literature. This work has taken a toll on Justine, but she finds support in Melanie.
Professional obligations (1.39.37)
Justine, Melanie and Jason deliberated doing their study because they knew how many people it would make uncomfortable, but they also knew they had a professional obligation to let the public know. Justine hopes their work inspires people to do new field experiments and contribute to the body of ideas in the field so that the public believes that “science is not the only tool but it’s a good tool to understand our world”. She looks forward to doing her own field experiments with humility and awareness.
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