Forests have always been magical places. But in the last couple decades, they seem to have gotten a little more magical. We've learned that trees are connected to each other through a vast underground network—an internet of roots and fungi often called the "wood wide web". We've learned that, through this network, trees share resources with each other. And we've learned that so-called mother trees look out for their own offspring, preferentially sharing resources with them. There's no question that this is all utterly fascinating. But what if it's also partly a fantasy?
My guest today is Dr. Justine Karst. Justine is a forest ecologist at the University of Alberta. Her research focuses on mycorrhizas—these are the symbioses formed between fungi and plant roots that are thought to be the basis of the "wood wide web." Last year, Justine and colleagues published a perspective piece in which they argued that some of the claims around the wood wide web have gotten out of hand. These new ideas about forests, they argued, have gotten decoupled from the actual on-the-ground—or under-the-ground—science. In reality, it's a field still riddled with unknowns and mixed findings.
Here, Justine and I do a bit of mycorrhiza 101—we talk about what mycorrhizas are, how they evolved, and what the structures actually look like. We discuss the original 1997 study that inspired the term "wood wide web." We consider why it's so hard to figure out what's actually going on, mechanistically, under the forest floor. We discuss the increasingly popular notion of plant intelligence and what it means to empirical researchers in this area like Justine. We talk about why people—both members of the public and scientists themselves—have found wood wide web ideas so charming. And, finally, we discuss the question of whether a little bit of hype is really so bad—particularly if it gets people excited about forests, about science, and about conservation.
I got as excited about the "wood wide web" as anyone. The idea totally captured my imagination a couple of years ago. So I was intrigued—if also a little dismayed—to learn recently that these ideas were getting some pushback. And I knew immediately we should talk to one of the researchers leading that pushback.
Alright friends, let's get to it. On to my conversation with Dr. Justine Karst. Enjoy!
A transcript of this episode is available here.
Notes and links
5:00 – Popular treatments sometimes mentioned as over-hyping the wood wide web (and associated ideas) include The Hidden Life of Trees, Finding the Mother Tree, and the novel The Overstory.
9:30 – The landmark 1997 paper by Simard et al. that kicked off interest in the so-called wood wide web.
11:00 – A study showing that fungi are more closely related to animals than to plants.
11:30 – For more on the new interest in "plant intelligence" see our previous episodes here and here. On the notion of "fungal intelligence," see here.
18:00 – A 1975 paper presenting a hypothesis about the origins of land plants.
20:00 – The California "mushroom bible" mentioned.
23:00 – A brief post (and infographic) on the differences between arbuscular mycorrhizas and ectomycorrhizas.
23:30 – Richard Powers' influential novel, The Overstory. Note that the novel doesn't exclusively focus on the wood wide web; it covers ideas and findings about trees and forests, many of which are uncontroversial.
36:00 – Dr. Karst co-authored her perspective piece in Nature Ecology & Evolution with Dr. Melanie Jones and Dr. Jason Hoeksema.
50:00 – For more on aspens and how they constitute clonal organisms, see here.
52:00 – The "mother tree" idea was popularized in Dr. Suzanne Simard's book, Finding the Mother Tree.
1:04:00 – Another recent critique of the wood wide web and mother tree idea is here. In it the authors write: "Reaching out to the general public to make people care about forests is certainly a praiseworthy goal, but not when it involves the dissemination of a distorted view of the plant world. In other words: the end does not justify the means."
1:05:30 – Others influenced by The Overstory include Barack Obama and Bill Gates.
1:09:00 – A primer on myco-heterotrophic plants.
1:13:00 – See a recent presentation by Dr. Jared Farmer on trees and "chronodiversity" here.
Recommendations
'Seeing plants anew,' Stella Stanford
'Mother trees and socialist forests: Is the 'wood-wide web' a fantasy?', Daniel Immerwahr
Many Minds is a project of the Diverse Intelligences Summer Institute, which is made possible by a generous grant from the John Templeton Foundation to Indiana University. The show is hosted and produced by Kensy Cooperrider, with help from Assistant Producer Urte Laukaityte and with creative support from DISI Directors Erica Cartmill and Jacob Foster. Our artwork is by Ben Oldroyd. Our transcripts are created by Sarah Dopierala.
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