Four short decades ago, the prevailing wisdom among forestry officials was the “Free To Grow” model by which, when a forest was clear cut for lumber, the earth was to be cleared of as much vegetation as possible to make room for planting monocultures of the most profitable trees, neatly spaced in symmetric grids. Allowing other shrubs and trees to exist next to your cash seedlings, everybody knew and instinctively felt, would rob resources from those seedlings and doom them to an early demise.
The problem was, the ideal Free To Grow forests of government theory were proving to be anything but robust. Stricken by disease, heat shock, and more susceptible to short term water shortages, these designed forests were not prospering as they should have, but as there was too much bureaucratic inertia at that point behind the Free To Grow concept, it seemed likely that it would continue as the central dogma of reforesting for decades to come, replacing vibrant and diverse forest life with acres of barren, herbicide soaked soil from which one variety of trees struggled to strain its way skyward.
In 1980, however, a woman employed by the foresting industry took a look at the yellowed and dying saplings growing from their professionally cleared patches of earth and, as all good scientists do, asked herself the great Why which would determine the course of all her coming days: why, removed from all competition for resources, did these trees appear to be doing worse than those left to grow amongst all manner of competitors in the wild forest?
Her name was Suzanne Simard, and in the decades to come her experiments would rewrite all of the central dogmas of forest management, though at an often cruel personal cost. She grew up the descendent of a long line of hard-living Canadian frontiersmen, who had carved their livings from the timber of the Canadian wilderness at the sustainable scale of pre-modern logging practices. She grew up a hard-scrabble, dirt-chewing tomboy who had the wild expanses of the northern forests as her playground. She knew from an early age about the rich world of fungal connections that lived just beneath the forest’s top layer of decaying leaves, a branching universe of multitudinous mushrooms and sprawling subterranean structures that all could agree were beautiful and awesome, but probably nothing more than that.
The wilderness loving child grew up to do what many forest-attuned Canadian youth did, and got her first jobs working for the local timber industry, plotting out clear-cut sites and evaluating prescriptions for how the cleared fields ought to be re-planted. The goal was to plant as much of the fastest growing, most profitable trees there were, and to eliminate anything else that competed with those cash trees. Simard suspected, however, that this policy was not only ecologically unsound, destroying biodiversity in exchange for one particularly desirable species, but also ultimately self-defeating. Leaving the timber industry, she began working for the British Columbia Ministry of Forests, where she had opportunities to test her theories about how fir saplings interact and perhaps even cooperate with neighboring shrubs and plants that ultimately improve their long term health and survivability.
Her investigations concentrated on the potential role of fungal networks in acting as intermediaries between fir saplings and more established plants for the exchange of crucial resources. Those branching networks are capable of rapid response to environmental change and of forming mycorrhizal attachments to plants through which they can transport nutrients and water in the soil to those plants in exchange for their photosynthetically generated sugars. One of the primary problems of Free To Grow approaches was that they destroyed these systems and the plants they sprung from, leaving new seedlings with nothing to connect to in the soil, and nothing to protect them from infection.
Through a series of rigorously planned and executed experiments, Simard discovered that not only do saplings draw nutrients from fungal webs in the soil that they are directly connected to, but that trees of different types can shuttle resources back and forth to each other through these intermediaries. Birch, for example, which logging companies considered a natural enemy of pine, turned out to play a much more complicated role than anticipated, with the deciduous tree and the conifer shuttling carbon back and forth to each other as each hit its preferred season for photosynthetic activity. Even those pine saplings growing in the direct shade of birch received enough benefit from the sugars flowing from the faster growing trees, not to speak of the resistance to disease-causing bacterias conveyed by the birch’s roots, to offset the diminished access to light and allow the tree to grow.
Simard’s results were showing, to put it mildly, that the reigning orthodoxies of forest practice were dangerously unsophisticated in their approach to the inter-dependencies of forest life, and they won her few friends in the field. Threatened by this newcomer who dared question the wisdom of clear-cut techniques followed by herbicide-soaked bare-soil grid planting, they were actively hostile to her ideas and eventually Simard was informed that her job was not secure, and she would do well to find other means of employment.
Married, with a young daughter, and without a steady income in the household, tough decisions had to be made. While her husband insisted they could live a simple life in the woods without the need to make much money, Simard did not want to abandon the research which she was sure held the key to a saner North American forestry policy, and wanted instead to take a position at the University of British Columbia. Her husband did not want to move to the city and take up a “Mr. Mom” role in the household, but ultimately agreed to try it for two years as Simard attempted to balance teaching, an ambitious research program, and the demands of home life. Some time after the two year trial period, Simard’s husband returned with the children to the comparative wilderness of Nelson, British Columbia, a nine hour drive that Simard gamely attempted every weekend to be with her family.
It was, in the end, a crushing load to bear, and Simard’s marriage would ultimately not survive the strain. All the while, however, her professional life was uncovering ever more startling layers of forest complexity. Working with her graduate students and a growing cohort of collaborators, Simard established that the forest’s oldest trees, which she termed “Mother Trees”, are bound in a tight relation to the seedlings connected to their fungal web, and are able to recognize which trees in that web are related to them, and which are not, and are able to preferentially send more resources to those individuals who are their kin.
Take a moment to let that set in.
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Okay, continuing on. Simard and her team found that, when an elder tree is stressed, and approaching death, it shoves its stored-up resources out into its network, giving its last drops of nutrients and energy to its offspring to allow them to better survive, and also conveying information to those offspring about potential dangers they should start protecting themselves against. Put together, her four decades of research (part of which were carried out while suffering from, and ultimately surviving, breast cancer that had spread to her lymphatic system) represent a grand recognition that, just beneath the soil, trees utilize an elaborate communications system which allows them to shuttle water, carbon, nitrogen, and other nutrients to the places where it is most needed, to recognize genetically related individuals, to warn each other about coming threats, to pool resources to protect against infection, and to use the particular strengths of each tree in a common grid that benefits all.
Little wonder, then, that the saplings Simard found in the 1980s shoved into bare earth, for all the access to sun and water that they enjoyed, found survival difficult. To indulge in some shameless anthropomorphization, it would be akin to taking an orphan child, and sticking them without supervision in a mansion stocked with nothing but candy, and expecting them to thrive. It takes a forest, a living and complex biome, to grow a tree, and until we take Simard’s evidence seriously and adapt our foresting policies accordingly, we shall continue to make the mistakes of the past, reaping nature’s accumulated bounty and sowing a dangerously diminished future.
In the nearly half century since Simard began her studies, a new generation of forestry officials has risen, free of many of the dogmas of the past, and the good news is that they are starting to heed the data Simard has dedicated her life to accruing, and are writing policies for how forests are to be logged and replanted that take into account Simard’s discoveries about the importance of diverse mycorrhizal connections. Meanwhile, Simard herself continues to speak for the trees, sharing her discoveries through Ted talks, through the Mother Tree Project she founded in 2015, and most recently through her memoir, Finding the Mother Tree: Discovering the Wisdom of the Forest, published in 2021. She has survived professional scorn and prejudice, deep personal loss, and the vicious machinations of cancer, and stands today directing our attention to the forests that will determine so much of our global future, to observe and learn and ultimately, if we are wise, to act.