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To some, forest ecologist is a pioneer in the tradition of Jane Goodall, Rachel Carson and Lynn Margulis. To others, she has veered too far from what science tells us. In 1997, she published a breakthrough paper showing that trees exchange food and nutrients via an underground fungal network connecting their roots, a system the journal Nature dubbed ““.

In 2021, Simard published . Her work found a huge new audience, tapping into a public thirst for evidence of community in nature, much like James Lovelock’s Gaia hypothesis. But, as with Gaia, there was an intense backlash, as some researchers objected to the claim that trees shared resources.

Simard grew up in a family of loggers and knows better than most the damage that unsustainable modern forestry practices are having on ecosystems. As an academic at the University of British Columbia, Canada, she runs the Mother Tree project, a major research programme aimed at understanding the relationships between trees in forest ecosystems. Drawing again on that work, she has just published , a sequel to Finding the Mother Tree.

Rowan Hooper: What is the “mother tree” concept?
Suzanne Simard: I did research to demonstrate that trees form communities; they are in relationship with each other. In the rainforest of British Columbia, I showed the trees are connected below ground through fungal networks and they communicate by shuttling resources.

I was looking at photosynthate [sugar made by photosynthesis] moving between trees and how the mother tree is the most connected tree because of its ability to combine all the connection points. Mother trees just have many more points of connection with all the other trees. They regenerate the forest, they provide seedlings that tap into the networks of old trees and that facilitates their regeneration.

So the mother tree is really just the biggest, oldest tree in the forest, so highly connected and important in regeneration.

It’s not just offspring this network is connecting, it’s other species?
Yes. When I published my work in Nature and on the cover they called it the “wood wide web”, I was looking at connections between paper birch and Douglas firs, two very different species. I found they shared resources. The direction of how and where the resources went depended on the photosynthetic ability of those trees, whether it was spring, summer or fall, whether they were shaded or not. The richer tree was providing more to the tree that had more of a need for photosynthate.

When did the backlash start?
I would say there were two waves. The first was a little wave in the late nineties. It was mostly UK scientists. They said there wasn’t enough evidence. I did rebut the criticisms and it died down. It was really after Finding the Mother Tree the tsunami of criticism started.

A of all your work said the evidence that the fungal network persists for a long time isn’t good enough. What happened next?
All those criticisms were looking for flaws, saying that there isn’t enough evidence fungal networks exist and we’re overinterpreting their importance. They would say things like, she’s discounting the importance of competition in forests. But I always talk about the multiplicity of interactions, including competition. I each point, one at a time. I was really flattened. I was really low. I was fortunate I was able to go to the rainforest and talk to the Indigenous people and really understand their dream culture and reverence for trees and connection to the spirit world through the trees.

I felt so at home. I came away just going, yeah, I’m going to continue my work talking about this because this speaks to us globally as people.

Would you say you’re still a scientist?
I’m very much a scientist.

I don’t mean that in a bad way, but perhaps science might not be enough for what you want to do?
Sometimes I’ve said I’m a recovering scientist. I still use the scientific method because I recognise its power. We can publish our work in reputable journals and people say, well, that’s peer reviewed, it must be credible. At the same time, I recognise its limitations and try to use it to help people see the much deeper understanding of us and our relationship to the world in Indigenous knowledge systems.

So you do your science in the traditional way, then write books, which allow you latitude to talk about interconnectedness.
People get that the world is a connected place. Our very societies and communities are built on our relationships, and I wanted to tap into people’s knowledge and say, you know what? We really need to embrace this because we’ve forgotten where we came from and we’re seeing our world unravelling. And in the scientific community, those messages were not getting out. So that’s why I wrote the book.

Do you think that is part of the pushback? Because you went a bit further than science allows?
If you want to reach people, you need to capture their imaginations, and people understand stories, right? Scientific writing is not story, it’s a method for delivering information in a really efficient way. A story captures people’s imagination, and when it’s your own story about how science works or how that science was done, people become engaged.

You’re right, I did take the science and I interpreted it in ways that I felt were important to me, and some people might say that I went beyond the realm of science. I guess that was kind of the point, to really bring the humanity into this.

We spoke about the mother tree, but what about your huge, scientific Mother Tree project?
The Mother Tree project is a thousand kilometres long. It crosses a climate gradient from hot/dry forest to cold/wet forest. The idea is that this gradient can represent how climate becomes more arid. We can use it to make predictions and demonstrate how forests will change.

We’re trying different methods of leaving old trees, mother trees, behind while doing some logging, comparing letting a forest grow on its own to harvesting from below, thinning out some of the smaller trees, making little gaps in the canopy, taking out 70 per cent of the forest and leaving 30 per cent in patches.

We’re finding amazing stuff. For example, that leaving old trees behind really matters. You can protect carbon pools. You can protect biodiversity, especially species that live in old forests.

Is it true James Cameron’s hometree in the Avatar movies was based on your work?
Yes. I hadn’t seen Avatar, but I got a phone call saying, “we’re looking at your work to guide our ideas”. I thought that was really cool.

Avatar is way beyond science now, but it gets interconnectedness…
Kids get this right away, because their world is really expansive. When I was a kid, the trees were my friends, who I played with.

You felt part of nature like many kids do. Was that knocked out of you when you worked in forestry?
That’s exactly true. I always had this connection and understood the forest. And then when I went to university, they told me the forest didn’t work that way, that trees are not in a relationship, they’re individuals and we can grow them up to be big and strong and then cut them down.

But it’s not how a forest works. You can’t just remake it in your own image and have it be healthy and strong. I pulled away and said, I need to understand what I know already [about connectedness] and demonstrate it using scientific methodology – for myself, but also to change forestry practices.

How’s your mission to change the forestry industry going?
Forestry has become more and more extractive. We’ve got more and more loss of old-growth forests. But things are changing in terms of how people feel. They see how our landscape has been changed by industrial logging, and they’re not happy, they’re pushing industry to change. But we’ve lost so much in the process.

This is an edited version of an interview from �鶹��ý‘s podcast The World, the Universe and Us