The first half of Dr. Suzanne Simard’s 2021 book “Finding the Mother Tree: Discovering the Wisdom of the Forest” was discussed in a previous article. This guide focuses on the second half, and her conclusion that the ancient Mother Trees must be preserved so that forests are resilient and healthy.
Simard takes the reader through her experimental design processes, from her earliest experiments to her most recent data-gathering trips. Few of her experiments contain less than 50 tree seedlings, and most of them take months or years to begin producing data. Because of this, the experiments are long and tedious, but they reveal critical data to support her hypotheses about the mycorrhizal (fungal) network that trees use for communication.
Two decades after Simard first planted birch and fir saplings, she returned to the area to make observations on their growth and connections. The conclusions she had made after the first few years were still accurate descriptions of how the trees had grown and connected. She says that, “In the early years, the mycorrhizal connections with birch had helped the fir saplings grow taller, and in adulthood, this head start still mattered. Two decades later, firs performed better in the neighborhood of birches than where they’d been cut off from their neighbors or where they’d grown only among other firs.”
The firs were healthier, too, with better nutrition and less disease. “Grown intimately together, this forest had almost twice the productivity of the stands” where Simard had dug trenches to cut off the root network. “This was the opposite of the usual foresters’ expectations,” she points out.
Coast Salish people teach that trees have personhood, and that they demonstrate symbiosis because they are connected by a web of fungi underground that keeps them strong. The Skokomish people tell a similar story about a network of roots and fungi. Simard talks about how this is different from western science, which mandates the dissection of systems to look at each of their parts in objective isolation, and how this makes it difficult to publish research on an entire ecosystem.
“Somehow,” she writes, “with my Latin squares and factorial designs, my isotopes and mass spectrometers and scintillation counters, and my training to consider only sharp lines of statistically significant differences, I have come full circle to stumble onto some of the indigenous ideals: Diversity matters. And 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 the other creatures.”
Old trees have weathered countless stressors over their long lives, and they carry the specialized chemicals that allowed them to survive. Simard’s research has shown that these Mother Trees pass along these chemicals—the memory of the stressors—to their offspring and their neighbors. This happens between trees of different species, also, as she showed in an experiment involving Douglas firs and ponderosa pines. Even dying or injured trees donate their residual carbon to nearby kin, as Simard detected using isotope-labeled carbon dioxide.
Simard says that seedlings grown in nurseries, without the need or ability to seek out additional water and nutrients through their roots, often suffer when transplanted into a forest because they can’t connect to the Mother Trees or the community through the essential mycorrhizal network. However, when forests are allowed to regenerate on their own, or are planted with accommodation to this vital network, they are healthier and more resilient.
“Ecosystems are so similar to human societies — they’re built on relationships,” Simard explains. “The stronger those are, the more resilient the system. […] Our success in coevolution — our success as a productive society — is only as good as the strength of these bonds with other individuals and species. Out of the resulting adaptation and evolution emerge behaviors that help us survive, grow, and thrive.”