Suzanne Simard, a professor of forest ecology at University of British Columbia, author of Finding The Mother Tree: Discovering the Wisdom of the Forest and founder of the Mother Tree Project , grew up in the cedar and hemlock inland rainforests of British Columbia in a family of loggers, a dangerous occupation, in which many of her family members were seriously injured. For a while, she also worked in the logging industry until her distress at rapacious clear-cutting set her on a different course. That association with the forest was Suzanne’s entrée into a world that aroused her fascination and curiosity with soil, plants, trees, and forest ecosystems. Her intrigue in the forests ultimately led to a breakthrough scientific discovery dubbed the “Wood Wide Web” by Nature magazine that revealed the symbiotic biological exchanges and communication between forest species via underground mycelial networks. Dr. Simard had to fight through a male-dominated culture in her field to have that discovery taken seriously, but now her brilliant work is being increasingly accepted and has profoundly changed the way we understand forest ecosystems. Bioneers Restorative Food Systems Director, Arty Mangan, interviewed Suzanne Simard at a Bioneers Conference.

ARTY MANGAN: Suzanne, as a doctoral student, you discovered something about the forest that radically upset the status quo. That discovery challenged the dominant idea that the relentless competition for resources was invariably the primary driver underlying the behavior of all living species. What did you find, and how was that discovery received by the scientific community?

SUZANNE SIMARD: I realized that our forest management practices were very destructive. We were trying to turn our old growth forests into plantations on the assumption that we needed to manage the native plants as weeds so that they wouldn’t compete with the marketable conifers. By managing the forests to reduce biodiversity, we were inviting all kinds of distress. Trees were getting infected by pathogens and insect infestations. They seemed to grow well at first, but I could see that they were not going to become healthy trees in the future, and that these forests looked so different than the native old-growth forests that they were replacing.

This led me to look below ground to try to figure out what we were disconnecting. I wasn’t the first person to discover that some mycorrhizal fungi can be symbiotically helpful to trees, that they take photosynthate from trees and use it to grow their mycelium that runs through the soil and simultaneously gather nutrients and water that they bring back to the trees in exchange for that photosynthate. This symbiosis was ubiquitous in our forests; all of our trees depended on it for their lives. The first person to publish on this was David Read in the United Kingdom, and other people were also looking at the likelihood that trees were connected below ground, but it wasn’t common knowledge. I wondered whether the underlying problem with our forests was that we were disconnecting these mycorrhizas that could actually link trees and plants together.

So, I spent decades of my career on that, and I’m still continuing to try to understand these connections in the soil. It really is a “wood wide web,” a sort of internet below ground with a remarkable density of connections. There are thousands of kilometers, even under a square meter of soil, of fungi linking all these plants together. There are avenues of communication from plant to plant, tree to tree.

Deciduous trees such as paper birch and aspen were being killed with herbicides because they were perceived as competitors to the conifers, but in my Ph.D. research, I found that birch and Douglas fir were actually linked together by mycelial webs below ground and were sharing carbon, nitrogen and water back and forth between them, sometimes even very quickly. There is a rapid communication going on. It took us years to figure out how quick it is. These resources, carbon, water and so on, are moving within minutes, hours, over days, years, and it’s a back-and-forth exchange.

Also, the more shade that these so-called weeds were casting on the coveted conifers that were the marketable wood, the more they actually shared carbon with the conifers. So, it led me to realize that we were looking at forests from such a very narrow point of view. Trees and plants are in a sophisticated relationship with each other, and they communicate in very sophisticated ways. Yes, they definitely do compete with each other, but they also collaborate, and it works to their advantage. It actually provides them with vigor and health. Trees are fitter when they grow in biodiverse communities than when they grow alone, but the forest management practices of reducing biodiversity were resulting in less healthy trees and forests. 

There was intense backlash to my findings, mostly because there is a huge chemical industry that profits when chemicals are used to exterminate native plants in forests. It was really about money, and it’s not an easy task to dismantle an entrenched system and structure. I still haven’t done that. There’s an enormous infrastructure and way of doing things built around this belief that competition between species is the only driving force in forests: the development and use of herbicides, how we plant trees, how we work with the plants around them, how we space them apart, how long we let them grow, etc. All of that machinery is put in place in support of the idea that trees just compete with each other. But in fact, that’s not the case. They have very sophisticated ways of communication and interacting that includes collaboration as well.

ARTY: You come from a family of forest loggers who selectively logged the forest and who at least had some sense of overall forest health. Today, devastating forestry practices clear-cut large swaths of forest using huge pieces of equipment weighing as much as 60,000 pounds that are brutally efficient in felling and processing trees. Viewing videos of those feller-buncher machines in action, I felt as though I were witnessing acts of brutal violence. What is the effect of clear-cuts on mycelial networks and on surrounding ecosystems?

SUZANNE: This is something that we’re looking at more and more carefully. Traditional forestry practices started out with horse-logging and hand-falling, so the impact was mostly pretty minimal. Growing up in a family of horse-loggers, I saw the forest as a regenerative place and forestry as a regenerative practice. When my great-grandfather and grandfather and dad would take out individual trees, the forest went through a succession phase. It regenerated very easily. The forest seemed to me to be a very healthy and vibrant place.

But when I became a forester in the 70s and 80s, I realized that wasn’t how forestry was being done. It had become a massive industrial money-making business. Of course, my family was trying to make a livelihood, but it wasn’t a corporate endeavor to make as much money as possible by exploiting forests on a massive scale.

And it kept getting more destructive. Hand-falling gave way to more mechanized falling, then the use of feller-bunchers, and now they use things called “hoe chuckers” that can move up steep slopes and get to places where even 20 years they couldn’t get to. Some of these hoe chuckers even operate at night without people in them. These robots that go in and harvest trees in places that used to be impossible to get to.

Let me give you an idea of the impact of this sort of industrialized logging. I’ve done a lot of research on it, especially as part of the Mother Tree Project, and what we’ve found is this huge loss of the most fertile topsoil from the forest floor. The forest floor is extremely important because it’s where most of the nutrients are contained and where most soil biology occurs. Organic material is mixed in with mineral soil, and it looks very black or dark. It’s full of life, of a whole web of organisms that are working together.

What we found in the Mother Tree Project and verified through many observations in looking at these logging practices is that, in our interior forests, these mechanized harvesting systems are causing the loss of about 60% of the carbon from the forest floor, and this is a big increase from earlier analyses of forest floor loss even just a decade ago. It’s largely because our mechanization and our machinery has changed. Back then, using rubber tire skidders and so on, we were only losing about 30%, so we’ve doubled the losses of soil fertility.

I was on a field trip in the old growth forests in the coast regions with the Kwakwaka’wakw people, which is a nation on the eastern side of Vancouver Island. Next to that was a forest that had been hand-felled 130 years ago, and, about 100 meters away, another piece of forest that had been logged a second time, so in that area the old growth forests had been logged and the second growth logged again. It was now third growth. In the old growth portion, the forest floor is about a meter deep. Right next door in the 130-year-old hand felled forest soil, it was only 50 centimeters, so, even from that old conventional harvesting, half of the forest floor had been lost. In the third growth stand, the forest floor was down to four centimeters. This is an enormous loss.

And just to put it in context at a national scale, Canada contains 25% of the world’s soil carbon, so the country has a global responsibility to be looking after these forests in a better way than what’s going on right now if it wants to be a responsible actor re: climate change.

ARTY: One aspect of your work is that it exposes the deep problems that result from our attempt to industrialize living systems, and some of the language you use, such as “mother trees” and “communication among trees,” seems to point more toward traditional Indigenous knowledge than to contemporary scientific nomenclature, and you once said that the Coast Salish were more scientific in their approach than we are. Can you explain that?

SUZANNE: The coastal nations of the Pacific Northwest, including the Coast Salish, the Nuchatlaht, the Kwakwaka’wakw, the Heiltsuk, the Haida, the Tsimshian, and the Tlingit ­– all the way up and down the coast­– have lived there for thousands of years. On Haida Gwaii, some estimates say that the Haida people were there for 14,000 years. More conservative estimates are that they were there since glaciation, about 10,000 years. Over those thousands of years living on the land, through a process of trying things, observing, adapting, changing, they developed very sophisticated methodologies for stewarding that land they knew so well. It was, of course, in their best interest to look after the land, to respect it, because the land gave back. Those Indigenous cultures’ worldview is that we are all connected, that people are part of the land and the land is part of us.

The ancient land-based wisdom worked well. Many of those societies were very prosperous and developed remarkable culture and art. One example of this is their relationship with salmon. Along the north coast, where I’m from in British Columbia, the people depend on salmon, and they also depend on cedar, which they view as the tree of life. They work very carefully to maintain salmon populations. They use fishing technologies that allowed them to monitor the salmon populations.

From time immemorial, they built tidal traps that have walls made of stone placed under the tide, and during spawning season when the tide comes in and out, the salmon get trapped behind the walls, so they could passively but effectively fish for salmon, but they always knew which ones were the big mother fish, and they let those big mothers migrate upstream and spawn in their natal streams. The mothers, the big old fecund females, laid big eggs that made big fry and created a big healthy salmon population that was sustainable year after year. The carcasses of many of those salmon were carried into the forest and eaten by bears and wolves, and whatever was remaining decayed into the forest floor and was taken up by the trees as nutrients. It provided a crucial natural fertilizer for the trees.

The cedar tree, the tree of life, was very important culturally for all of these nations in that it provided food, shelter, clothing, mats, and boxes. It was very much a part of their lives. They were caring for the trees at the same time that they were looking after the salmon that were basically fertilizing these forests. It was an extremely effective circular flow that involved wisely cooperating with natural systems to guarantee that your people had their needs amply met but that the underlying ecology stayed vital.  

The well fertilized trees would grow big and protective and provided wealth. They also shaded the streams for the salmon fry, which would then go back out to the ocean to carry out the rest of their life cycle. In this way, by monitoring the fish, by selecting the big mothers so that they could go upstream to spawn, they actually enhanced the salmon populations. They were working together with their resources by monitoring and watching and adjusting. Now, if that’s not science, I don’t know what is.

Then colonization came and took over that salmon fisheries practices, and Western science was applied to the harvest. Well, we know what happened to the salmon populations since then because the supposedly “scientific” methods weren’t based on thousands of years of observation of and attunement to what was happening in the salmon runs. That’s why I call the Indigenous way a more sophisticated science. It’s based on a lot more knowledge, care, and adaptation.

These connections are sacred. The connections between people, salmon, trees, wolves, bears, eagles, waters, forests, oceans are sacred relationships that need to be maintained because once they’re broken, then the systems unravel. The indigenous people knew that, and we’re seeing this great unraveling now, expressed in catastrophic loss of biodiversity and in the ravages of climate change.