Finding the Mother Tree: Discovering the Wisdom of the Forest

by Suzanne Simard

The trees soon revealed startling secrets. I discovered that they are in a web of interdependence, linked by a system of underground channels, where they perceive and connect and relate with an ancient intricacy and wisdom that can no longer be denied.

One of the first clues came while I was tapping into the messages that the trees were relaying back and forth through a cryptic underground fungal network. When I followed the clandestine path of the conversations, I learned that this network is pervasive through the entire forest floor, connecting all the trees in a constellation of tree hubs and fungal links.

Chemicals identical to our own neurotransmitters. Signals created by ions cascading across fungal membranes. The older trees are able to discern which seedlings are their own kin. The old trees nurture the young ones and provide them food and water just as we do with our own children. It is enough to make one pause, take a deep breath, and contemplate the social nature of the forest and how this is critical for evolution. The fungal network appears to wire the trees for fitness. And more. These old trees are mothering their children. The Mother Trees.

When Mother Trees—the majestic hubs at the center of forest communication, protection, and sentience—die, they pass their wisdom to their kin, generation after generation, sharing the knowledge of what helps and what harms, who is friend or foe, and how to adapt and survive in an ever-changing landscape. It’s what all parents do.

The scientific evidence is impossible to ignore: the forest is wired for wisdom, sentience, and healing. This is not a book about how we can save the trees. This is a book about how the trees might save us.

Humus is the greasy black rot in the forest floor sandwiched between the fresh litter from fallen needles and dying plants above and the mineral soil weathered from bedrock below. Humus is the product of plant decay. It’s where the dead plants and bugs and voles are buried. Nature’s compost.

We think that most important clues are large, but the world loves to remind us that they can be beautifully small.

Myco like fungus, and rhiza like root. Mycorrhiza was fungus root. My. Core. Rise. Ah.

saprophytes, the fungal species that decompose dead stuff,

They were helpers to plants, mycorrhizal fungi.

The mycorrhizal symbiosis was credited with the migration of ancient plants from the ocean to land about 450 to 700 million years ago. Colonization of plants with fungi enabled them to acquire sufficient nutrients from the barren, inhospitable rock to gain a toehold and survive on land. These authors were suggesting that cooperation was essential to evolution.

“The Coast Salish say that the trees also teach about their symbiotic nature. That under the forest floor, there are fungi that keep the trees connected and strong.”

Gunning for fast early growth by weeding out native plants in hopes of future profits was not going to end well. For anyone.

Why was it always so much work to stay connected? To be a family?

“I tucked this in with the other experiments,” I said, smiling. I was getting good at hiding the controversial ones among the mainstream studies when I applied for grants.

The sharing of energy and resources meant they were working together like a system. An intelligent system, perceptive and responsive.

Roots didn’t thrive when they grew alone. The trees needed one another.

clear-cutting and removal of birch was detrimental to the long-term productivity of the forest. The numbers showed that forest growth declined with each successive one-hundred-year cutting-and-weeding cycle. Without the companionship of birch, with its microbes transforming nitrogen along mycorrhizal networks and bacteria helping guard against root disease, the growth of pure Douglas-fir stands declined to half of that evidenced in mixtures with birch. Birch, on the other hand, maintained its productivity without fir.

Garden plants usually associate with arbuscular mycorrhizal fungi, unlike the ectomycorrhizal fungi on most trees.

There are only a couple hundred arbuscular mycorrhizal species worldwide, compared to the thousands of ectomycorrhizal species. These arbuscular mycorrhizal fungi are generalists, meaning that even the few species that exist in nature can colonize the roots and should link most of the garden vegetable plants. Like corn, squash, beans, peas, tomatoes, onions, carrots, eggplant, lettuce, garlic, potatoes, yams.

Plants are attuned to one another’s strengths and weaknesses, elegantly giving and taking to attain exquisite balance. A balance that can also be achieved in the simple beauty of a garden. In the complex society of ants. There’s grace in complexity, in actions cohering, in sum totals. We can find this in ourselves, in what we do alone, but also in what we enact together. Our own roots and systems interlace and tangle, grow into and away from one another and back again in a million subtle moments.

A later study would show that the roots of at least half of the pines in a stand are grafted together, and the larger trees subsidize the smaller ones with carbon. Blood runs thicker than water.

But my work was showing that some carbon also moved to unrelated individuals, ones of an entirely different species. From birch to fir, and back again.

Ecosystems are so similar to human societies—they’re built on relationships. The stronger those are, the more resilient the system.

“Kin seedlings also have heavier root tips than strangers and greater colonization by the mycorrhizas of the Mother Trees,”

seeing that Mother Trees are also bigger when they’re next to their kin?” Amanda asked. “It makes sense if they’re passing signals back and forth.” Of course it did. Being connected and communicative affects the parents as much as the kids.

“but the Mother Trees are sending more carbon to the mycorrhizal fungi of their kin than the others! Kin-recognition molecules seem to have carbon and micronutrients.”

“Even a tiny amount moving into the mycorrhizal fungi of the seedlings could mean the difference between life and death when the little ones are small,” I said. Germinants struggling to survive in the deep shade, or during the summer dry spell, could live instead of die with the slightest boost, the smallest of advantages, if it came at the right time. Not only that, the bigger the Mother Tree, the healthier she was, the more carbon she gave.

Communication among relatives is important, but it also matters in whole communities. In a couple of experimental families, the Mother Trees even gave as much to the mycorrhizas of a stranger as her kin.

Mother Trees give their kids a head start, but they also tend the village to ensure it flourishes for their young.

Maybe society should keep old Mother Trees around—instead of cutting most of them down—so they can naturally shed their seed and nurture their own seedlings. Maybe clear-cutting the old, even if they’re not well, wasn’t such a good idea. The dying still have much to give. We already knew the elders were habitat for old-growth-dependent birds and mammals and fungi. That old trees stored far more carbon than young ones. They protected the prodigious amounts hidden in the soil, and they were the sources of fresh water and clean air. Those old souls have been through great changes, and this affected their genes. Through the changes, they’d gathered crucial wisdom, and they offered this up to their offspring—providing protection, laps into which the new generations got started, the foundation from which to grow.

already seen that stressed firs passed more carbon to neighboring pines than did healthy firs, and Amanda had also discovered that, in the proximity of healthy Mother-Tree seedlings, kin seedlings had better nutrition than strangers, and their mycorrhizal fungi received more carbon. But so far we hadn’t seen whether dying Mother Trees passed their carbon legacy into the shoots, the lifeblood, of her kin seedlings, beyond the fungal web.

now we know Mother Trees can truly nurture their offspring. Douglas firs, it turns out, recognize their kin and distinguish them from other families and different species. They communicate and send carbon, the building block of life, not just to the mycorrhizas of their kin but to other members of the community. To help keep it whole. They appear to relate to their offspring as do mothers passing their best recipes to their daughters. Conveying their life energy, their wisdom, to carry life forward. The yews too were in this web, in relationship with their lifelong companions, and with people like me recovering from illness or just walking through their groves.

Diversity matters.

everything in the universe is connected—between the forests and prairies, the land and the water, the sky and the soil, the spirits and the living, the people and all other creatures.

Some mortality wasn’t a bad thing. It made room for diversity, regeneration, complexity. It kept the bugs down and created firebreaks. A lot of death, though, could cause a cascade of changes, rippling through the landscape, upsetting the balance.

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.

figured it would be a long shot if dying Douglas firs transmitted messages to ponderosa pines. But they did.

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.

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.

The concept of the Mother Tree and her connections to those around her had even made it into Hollywood, as a central concept to the tree in the film Avatar. How the film resonated with people reminded me how naturally crucial it is for people to connect to mothers, fathers, children, family—our own and the families of others—and to trees and animals and all of the creatures of nature, as one.

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.

Mistreatment of one species is mistreatment of all.

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.