Quirks and Quarks·Q&A

A pioneering forest researcher's memoir describes 'Finding the Mother Tree'

Suzanne Simard has found that forest trees are connected with an underground circulatory system that allows them to communicate and share resources, and that 'Mother trees' are the most connected of all.

Suzanne Simard's work has revealed the connection and communication between forest trees

Professor Suzanne Simard's new book is 'Finding the Mother Tree: Discovering the Wisdom of the Forest.' (Bill Heath)

Originally published on May 1, 2021

If you've ever walked through the forest and heard the whispering of the trees, it's easy to imagine that there's conversation happening — that there's a kind of intelligence in the community of the forest. Of course, in the modern technological world, it's easy to dismiss this sort of thing as airy romanticism. 

But biologist Suzanne Simard discovered, or perhaps rediscovered, the reality of the interconnection and intelligence of the forest. She's been able to find out that the trees are indeed whispering to each other — communicating not through the wind, but through the soil. 

Simard has spent the last four decades, with rigorous experiment and study, understanding how trees talk to each other. She's found that they are part of a mutually supportive community, sharing resources with both kin and strangers that are in need. In doing so, she's profoundly changed the way we should see forests.

Simard has just published a new scientific memoir describing her life and research. It's called Finding the Mother Tree: Discovering the Wisdom of the Forest.

Suzanne Simard is a Professor of Forest Ecology at the University of British Columbia.

Here's part of her conversation with Bob McDonald on Quirks & Quarks.

I didn't know how deeply your roots go into the forests you've studied. Tell me about that. 

I grew up in the Monashee mountains of British Columbia. I grew up in these cathedrals, these forests that had huge trees. That's the world I knew, and that's really the foundation of who I am and what I studied.

(Penguin Random House Canada)

My grandfather and his and my great-grandfather and all of my great-uncles and uncles and my dad were all horse loggers, and so I got to see how that was done. It was dangerous work. It was exciting work. It really shaped me. 

When you began your work in forestry, it seems that it was a bit of a shock to you and a disappointment as you realized how the industry actually worked. 

I absolutely love the forest, and I was thrilled that I was able to get a job and get a degree in forestry. I felt so fortunate. But of course, you know, I was one of the first girls. Also it was at the beginning of industrial clear-cut logging in the 1970s. When I became a young forester myself working for the industry, I was shocked. That's when I was really going 'hmm, I wonder what we're doing here.' 

You got some very early insights that trees aren't just biological units that can be extracted and then replanted. How did that start for you? 

I had gotten my master's degree, and my job was to grow young plantations using the techniques that were thought to be important at the time, which meant clear-cutting. And then we were planting trees and then weeding out all the native plants, or as many as people could get out of there. Because the view at the time — and it still is — that competition that encroached on these crop trees. The Douglas firs and the pines and spruces that we were trying to grow for profit were being robbed of their resources by these competitors. And that was done using herbicides or just cutting them out. 

It got me thinking, are we really doing the right things here? Don't these plants have some role to play in protecting these trees, to form a community with these trees? 

We were actually making the situation worse by short-circuiting natural successional processes, which increases the diversity of the forest, which actually now we know provides a lot of protection against insects and diseases and actually is more productive in the long term. 

An aerial view of an old-growth clearcut in the Nahmint Valley from May 2018. An exceptionally large Douglas-fir tree can be seen on the ground. (TJ Watt)

What was your first insight into the role of mushrooms and fungi in the health of the forest? 

I started to realize as I studied more and more — and eventually went and did my doctorate in this — that there are all these kinds of functional groups of fungi and the mycorrhiza are actually throughout our forests. These mycorrhizal fungi actually go into a symbiosis with the tree, where the fungus grows through the soil, picks up nutrients and water, brings it back to the tree or the plant ,and the plant gives it carbon or photosynthesis in exchange. I ended up just focusing on the mycorrhiza because I realized that they were so fundamental to the health of the forest. 

At the time, there was this new research coming out of the United Kingdom by Sir David Read, who was looking at in the laboratory how these mycorrhizal fungi can actually link up little pine seedlings together in little garden boxes and that they could actually transmit carbon from one seedling to another. And so I just became enthralled with that. 

Well, tell me about the deep insight you got from studying the relationship between birch and fir trees. 

When I saw the birch being weeded out, it was killing the firs. And so I thought, well, are they sharing these mycorrhizal fungi? Did they form a network? And so I did these early studies and I found that they are connected in the forests. And I did this labelling where I used isotopes, carbon 14 and carbon 13, labelling birch and fir with two different isotopes and then seeing these isotopes moved back and forth between these two different tree species. 

We were viewing Birch as the big competitor. While it was competing certainly for light, it was also shoveling carbon over to Douglas fir. And I view that as a way to enhance the diversity of the community. It was a community effect that kept that community healthy and alive.

Professor Simard at home in the forest (Jean Roach)

So you found that the fungi were actually sort of the circulatory system sharing resources between trees, even trees of different species? 

Yeah, yeah. Actually, that's a really cool way to say it, circulatory system. Blood is moving around in the forests, but it's actually resources, right? So they need carbon, they need nitrogen and phosphorus. They need water. And it turns out they're sharing all of this stuff through the circulation system constantly. 

Your work at UBC led to the idea of the hub tree, or the title of your book, The Mother Tree. Tell me about that. 

We did this project where we took six forests and we were able to map the fungal linkages between the different trees. And what emerged from the map was that everything was linked to everything else. All these trees were linked together, but the biggest trees and the oldest trees that were the most highly connected to all the other trees. 

I had graduate students who planted seeds around these old trees where they could connect the seedlings that were germinating, could connect with the old trees versus some that could not. And we found that the germinates [seedlings] that could connect to the old trees survive better and they grew faster and they had better nutrition. 

Ultimately, we also discovered that they could also recognize which were their own seedlings, their own kin. And so all of this work came together to convince me to call these not hub trees, which is a very forgettable word, but to call them mother trees, because of their nurturing ability in the forests. 

Simard's work has shown that giant Fir trees like this at Francis/King Regional Park in Saanich, B.C., can feed resources to neighbouring trees and even detect which saplings are related to it. (Chad Hipolito/Canadian Press)

Throughout your book, you make it clear that while you've worked out these ideas scientifically, that Indigenous peoples understood these relationships in the forest already. 

Yeah, and this is so amazing. This is perhaps the most important part. I was so fortunate that I got a postdoc in about 2015. Her name is Dr. Teresa Ryan, and she is Tsimshian Nation. And we just started working together and she really opened up the world for me. 

I had been struggling along as a Western scientist with this idea of connection. And why aren't we embracing the idea of a connection in forests? And talking to Teresa, she says, 'You know, we've always known about these connections. That is our world view.' 

So I realized at that point that what I was discovering with these Western scientific tools had long been known for thousands of years by the First Nations of Canada and the north and in the U.S. 

I hope what my work can do is help society to look more closely at what the Aboriginal people of North America and throughout the world have long known and listen to their wisdom, because it's there already. 

How do you see your findings about the interconnectivity in the forests changing the way we're doing forestry? 

Well, I'm hopeful that it will. So far it hasn't. I've started this project called the Mother Tree Project. The goal of that project is how do we better manage our forests for connection and so that these forests are resilient and healthy as climate changes. My work and Aboriginal wisdom shows that the forest relies on those connections to stay healthy. And so my hope is that we can take this and apply it to forest practices where we do more partial cutting to protect biodiversity, protect carbon foster regeneration. 

It's not a simple solution because at the same time that if we can shift to more selective cutting doesn't mean that we cut more area. We have to actually reduce our cut in order for this to work. And it's not rocket science. It's really just hard political decision-making. We have the science to guide it already. 

Produced by Jim Lebans