Finding the Mother Tree: Uncovering the Wisdom and Intelligence of the Forest

by Suzanne Simard

In the high-density plots—where the planted firs were only a few meters apart—the understory was dark. The floor looked bare except for rusty needles, their acidity slowing down the cycling of nutrients. Gray branches snapped off as we worked our way among the trees. I imagined the mycorrhizal network had taken on the pattern of the plantings, wiring trees together as if they were rows of telephone poles. It would become a little more complex as the bigger trees spread their limbs and roots, taking over the growing space where others had died. Our

we moved on to a plot where the firs were spaced farther apart, up to five meters, their girth a little more robust. Seed had dispersed into the openings between the plantings over the years, some probably their kin, others the descendants of those removed, still others from firs in the surrounding forest. Fertilized by pollen of neighbors, or by firs in other valleys, ensuring the population was resilient. Some of these new trees were toddlers, others kindergartners, still others juniors, this patch of forest starting to look like a schoolhouse, with diversity and kinship. The mycorrhizal network, I imagined, was becoming more complex as the forest aged, the biggest trees becoming the hubs—the Mother Trees. Eventually it would look like the web we’d mapped a few years back in the old-growth Douglas-fir forest.

In my first experiment testing whether birch transmitted carbon to fir through mycorrhizas, I thought I’d be lucky to see anything, but then I detected a pulse strong enough to fuel the setting of seeds. I saw fir giving back to birch the energy it needed to build new leaves in the spring. And my posse of students confirmed the findings of reciprocity, not just between birch and fir but among all sorts of trees. In making the mycorrhizal-network map, I thought we might see a few links. Instead we found a tapestry. With Yuan Yuan, I figured it would be a long shot if dying Douglas firs transmitted messages to ponderosa pines. But they did. Another of my students confirmed it in a second study, as did others in labs around the world. Then I considered it a gamble that Douglas-fir Mother Trees would recognize their own kin, never mind that the signals might move through the mycorrhizal network—and mon Dieu! The firs recognized their relatives! The Mother Trees not only sent carbon to help support their mycorrhizal fungal symbionts, they somehow enhanced the health of their kin. And not only their kin, but of strangers too, and other species, promoting the diversity of the community. Was this all luck?

I’d had a hunch those little yellow spruce seedlings back in 1980—the ones who’d sent me on this long journey of a lifetime—were suffering because their bare roots couldn’t connect with the soil. Now I knew they lacked mycorrhizal fungi, whose hyphae would not only have extracted nutrients from the forest floor but also connected the seedlings to the Mother Trees, providing them with carbon and nitrogen until they could stand on their own. But their roots had been confined to their plugs, isolated from the old trees. The subalpine fir that had naturally regenerated on the outskirts of the Mother Trees, though, had been lush with sustenance. But that lingering question since my illness still haunted me: If we are equal to everything in nature, do we share the same goals in death? To pass the wand as best we can. Passing onward to children the most crucial material.

Monika’s Mother-Tree seedlings transmitted more carbon to kin than strangers, as Brian and Amanda had found. But unlike the earlier study, where we’d only detected carbon moving into the mycorrhizal fungi of the kin seedlings, Monika now found that it went straight into their long leaders. The Mother-Tree seedlings flooded the mycorrhizal network with their carbon energy, and it advanced into the needles of her kin, her sustenance soon within them. Et voilà! The data also showed that injury, whether by western spruce budworm or the shears, induced the Mother-Tree seedlings to transfer even more carbon to her kin. Facing an uncertain future, she was passing her life force straight to her offspring, helping them to prepare for changes ahead. Dying enabled the living; the aged fueled their young.

My wish is that we might think twice about salvage harvesting the dying Mother Trees, might be compelled to leave a portion behind to take care of the young, not merely their own but those of their neighbors too. In the wake of diebacks from droughts, beetles, budworms, and fires, the timber industry has been cutting vast swaths of forest, the clear-cuts coalescing over whole watersheds, entire valleys mowed down. The dead trees have been considered a fire risk, but more likely a convenient commodity. Great numbers of healthy neighbors have also been captured for the mills as collateral damage. This salvage clear-cutting has been amplifying carbon emissions, changing the seasonal hydrology in watersheds and in some cases causing streams to flood their banks. With few trees left, the sediments are flowing down rivulets and into rivers already warming with climate change, harming the salmon runs even further. Giving a TED walk in Stanley Park at TED Vancouver, 2017 This

Scientists before me have discovered that the nitrogen from decayed salmon lives in the rings of trees along the rivers from where they came. I wanted to know whether salmon nitrogen was absorbed by mycorrhizal fungi of the Mother Trees and transmitted through their networks to other trees deeper in the forest. Even more, were the salmon nutrients in the trees declining with the reduction in salmon populations and habitat loss, causing the forests to suffer? If so, could this be remedied?

on the midcoast of British Columbia, in the salmon forests

Dr. Tom Reimchen of the University of Victoria and Dr. John Reynolds of Simon Fraser University had discovered salmon nitrogen in rings of cedars and Sitka spruces, and in the plants, insects, and soils. Allen would start our study of how mycorrhizal fungi might transmit the salmon into the trees, and possibly between trees, by determining how the mycorrhizal fungal communities differed alongside streams with various salmon population sizes.

Could a difference in the fungi, in their ability to transmit the salmon nutrients, help account for the great fertility of these rain forests? I could barely contain my excitement as Allen, Teresa, and I jumped into the sedges with our hip waders and headed to shore.

Each bear preying on the spawning salmon transported some 150 fish per day into the forest, where the roots of the trees foraged for the decaying protein and nutrients, the salmon flesh providing more than three-quarters of the tree’s nitrogen needs. The nitrogen in tree rings derived from salmon was distinguishable from the soil’s nitrogen because fish at sea get enriched with the heavy isotope nitrogen-15, which serves as a natural tracer of salmon abundance in the wood.

Scientists could use the year-by-year variation in tree-ring nitrogen to find correlations between salmon populations and changing climate, deforestation, and shifting fisheries practices. An old cedar tree could hold a thousand-year record

Teresa explained that when the colonists took jurisdiction of the waters and forests, they forbade use of the stone traps. The salmon were overfished within the first two decades and have yet to recover fully. Climate change and a warming Pacific Ocean have created new problems by exhausting the fish on their marathon from the ocean, reducing their success at reaching the natal spawning streams. It’s part of a general pattern of destroying interconnecting habitats. To the north on Haida Gwaii, the last of the cedars, some more than a thousand years old, are being clear-cut on Graham Island, leaving the forest along the spawning rivers degraded and the Haida wondering what will happen to their way of life.

This study is ongoing, but our early data show that the mycorrhizal fungal community in the salmon forest differs depending on the number of salmon returning to their natal streams. We still don’t know how far into the forest the mycorrhizal network is transporting the salmon nitrogen, and if—or how—restoration of the tidal stone traps might affect forest health, but we are starting new research and reconstructing some of the stone walls to find answers.

Of late I’ve become increasingly enchanted by the story told by Subiyay, who talks of the trees as people. Not only with a sort of intelligence—akin to us humans—or even a spiritual quality perhaps not unlike ours. Not merely as equivalent to people, with the same bearings. They are people.

The Tree People. I don’t presume to grasp Aboriginal knowledge fully. It comes from a way of knowing the earth—an epistemology—different from that of my own culture. It speaks of being attuned to the blooming of the bitterroot, the running of the salmon, the cycles of the moon. Of knowing that we are tied to the land—the trees and animals and soil and water—and to one another, and that we have a responsibility to care for these connections and resources, ensuring the sustainability of these ecosystems for future generations and to honor those who came before. Of treading lightly, taking only what gifts we need, and giving back.

Of showing humility toward and tolerance for all we are connected to i...

too many decision-makers dismiss this way of viewing nature and rely only on ...

The impact has become too devastating to ignore. We can compare the condition of the land where it has been torn apart, each resource treated in isolation from the rest, to where it has been cared for according to the Secwepemc principal of k̓wseltktnews (translated as “we...

I believe this kind of transformative thinking is what will save us. It is a philosophy of treating the world’s creatures, its gifts, as of equal importance to us. This begins by recognizing that trees and plants have agency. They perceive, relate, and communicate; they exercise various behaviors. They cooperate, make decisions, learn, and remember—qualities we normally ascribe to sentience, wisdom, intelligence. By noting how trees, animals, and even fungi—any and all nonhuman species—have this agency, we can acknowledge that they deserve as much regard as we accord ourselves. We can continue pushing our earth out of balance, with greenhouse gases accelerating each year, or we can re...

the planet has been waiting patiently for us to ...

Making this transformation requires that humans reconnect with nature—the forests, the prairie, the oceans—instead of treating everything and everyone as objects for exploitation. It means expanding our modern ways, our epistemology and scientific methodologies...

Mowing down the forests and harvesting the waters to fulfill our wildest dreams of material wealth just because we can has caught up to us. Hannah, age twenty-one, working in the bush and eating huckleberries, July 2019 I crossed the Columbia River at Castlegar, only half an hour from home, a...

We were at the Britannia Mine—forty-five kilometers north of Vancouver on the shores of Howe Sound on the unceded territory of the Squamish Nation—the largest mine in the British Empire, opened in 1904 to extract the ore bodies that had formed when volcanic pyroclast flowed onto sedimentary rock and the metamorphosed result came into contact with plutonic intrusions. The miners had quarried the faults and fractures where the rich ore lay, boring right through Britannia Mountain, from Britannia Creek on the northern flank to Furry Creek on the southern side, covering an area of about forty square kilometers. They left behind two dozen portals to 210 kilometers of tunnels and shafts, which stretched from 650 meters below sea level to 1,100 meters above.

Even after the mine closed in 1974, it remained one of the largest point sources of metal pollution to the marine environment in North America. Tailings and waste rock were used to fill in the shoreline, and Britannia Creek, containing kilograms of copper, flowed clear but devoid of life into Howe Sound, killing ocean life for at least two kilometers along the shore. Britannia Creek’s water was so toxic at the mine’s closing that Chinook salmon fry, when introduced, died within forty-eight hours.

Trees need to be near one another, to establish in receptive soil, to join together to build the ecosystem, mix with other species, relate in patterns that produce a wood-wide web, because the forest becomes resilient from this complexity. Scientists now are more willing to say that forests are complex adaptive systems, comprised of many species that adjust and learn, that include legacies such as old trees and seed banks and logs, and these parts interact in intricate dynamic networks, with information feedbacks and self-organization. Systems-level properties emerge from this that add up to more than the sum of the parts.

The properties of an ecosystem breathe with health, productivity, beauty, spirit. Clean air, clean water, fertile soil. The forest is wired for healing in this way, and we can help if we follow her lead.

Once the system hits a tipping point, once good decisions are made and acted upon, and when parts and processes are enmeshed again, and the soil rebuilt, recovery is possible—at least in some places.

Our goal is to further develop an emergent philosophy: complexity science. Based on embracing collaboration in addition to competition—indeed, working with all of the multifarious interactions that make up the forest—complexity science can transform forestry practices into what is adaptive and holistic and away from what has been overly authoritarian and simplistic. By

We have the power to shift course. It’s our disconnectedness—and lost understanding about the amazing capacities of nature—that’s driving a lot of our despair, and plants in particular are objects of our abuse. By understanding their sentient qualities, our empathy and love for trees, plants, and forests will naturally deepen and find innovative solutions. Turning to the intelligence of nature itself is the key.