By Sadie Doyle

The Conversations of the Wood Wide Web

By Sadie Doyle

In my hometown of Newburyport, Massachusetts lies Maudslay State Park, a formerly private property turned public park. It is 483 acres of field and forest, well-known for its towering white pines, and one that I have been exploring all my life. Located within a large estate historically owned by a wealthy family, there are naturally rumours that Maudslay is haunted. To scare each other, teenagers tell stories of deceased family members and staff wandering the grounds. The stories are fun, but there really is a spirit of sorts, and more to Maudslay—indeed more to any forest—than meets the eye.

The kingdom of fungi is an overlooked guiding hand in the foundations and functions of life. Popular image conjures small fruiting bodies, often umbrella shaped, popping out of the ground, but mushrooms are only the aspect of the organism that are easiest to see, and most species do not even have them. Fungi are mainly recognized as decomposers, but the depths of their roles are uniquely widespread and entwined with organisms. They are found nearly everywhere on earth, from marine sediment to human bodies, and ecosystems would collapse, or never exist at all, without them. They play parts in a great deal of different relationships, but I am specifically fascinated with fungi that grow in a relationship with plants, called mycorrhizae.

A common way for fungi to spread is through expanding their mycelium, a process by which they form branching, exploratory networks of tiny threads called hyphae. When they spread and connect with other mycelium underground, they form what are called common mycorrhizal networks and they connect nearly every tree in a forest by threading themselves into root hairs. Some mycologists refer to mycorrhizal fungi as keystone organisms; others call them ecosystem engineers. These unseen architects work to maintain the intricate dynamics of a forest.

If you have ever gone walking in the woods and felt that your environment is awake, it is. The feeling that you are not among many different individuals, but inside of something vast, is an accurate one. The trees around you and the soil beneath your feet are thrumming with energy and engaging in constant dialogue in a language that we are only just beginning to investigate.

Forestry has long been a science of harsh competition. The assumption was that the strongest trees live to grow up, and the weakest trees never make it to maturity, so foresters concluded that each tree stood alone in its quest for survival. This idea was carried out in forestry practices that prevented forests from forming strong communities to protect one another. If trees are all fending for themselves anyways, then foresters felt confident it made things easier for remaining trees if you cut down a large slew of trees at once, or harvested trees at the heart of an old-growth forest. It is not just forestry. Scientists have to balance two truths: that organisms are interconnected and dependent on one another to maintain balance, and that organisms have to compete with each other for limited resources. In forests, these two ideas fit together differently than traditional notions would dictate.

In 1984, English botanist David Read proved that it was possible for carbon, an essential element for plants to carry out photosynthesis, to pass between plants through fungal connections, something that had been hypothesized since the 1960’s but never demonstrated. He used donor and receiver plants, with or without mycorrhizal fungi present, and fed the donors radioactive carbon dioxide. For plants that did not have a fungal network, he detected radioactivity only in the donor plant, but with a fungal network, both plants showed radioactivity. These findings were significant progress, but the experiment had been conducted in a laboratory, so his conclusion did not suggest that carbon transfer between plants could happen naturally.

Canadian forest ecologist Suzanne Simard built off of Read’s findings when she designed a manipulative experiment on a tree plantation in British Columbia, and what she found changed the study of ecology forever. In an NPR article “How do Trees Collaborate?” Simard discusses her work. She took pairs of trees and exposed one tree in each

pair to carbon-14, a radioactive carbon isotope. She found that when the birch had taken up the carbon, its neighbor, the fir, had also absorbed it. One tree was given the isotope, but both trees had it. “I ran from plot to plot. And I checked all 80 replicates,” Simard says, “The evidence was clear. Paper birch and Douglas fir were in a lively two-way conversation.” Simard was the first to publish a study claiming that carbon can naturally move between trees through the fungal network connecting their roots. She also found that shaded fir seedlings, deprived of the sun that they need to carry out photosynthesis, received more carbon from birches than unshaded seedlings. The seedlings that were better endowed with sunlight were transferring their excess carbon sugars. Not only did they share, but they shared equitably. To a community of scientists that had been operating under the idea that trees thrived by diminishing other

trees, this was a radical finding.

Trees are not as competitive as we used to think, this is not to say that any ecosystem is a sentimental utopia of kindness. Professor Tony D’Amato, director of the UVM forestry program and research forests, weighed in on connections between trees in regards to forest management. He states, “there are scenarios where one tree is going to compete with another one. It’s not always going to be a harmonious kind of interaction.” Forests do have competition, since they contend with limited resources. However, the more we learn about how they function as a whole, the more it seems that collaboration is far more important to the success of the forest. These limited resources are often shared, not hoarded. In other words, a forest is not simply a mass of individual organisms because its success depends on the aid distributed to the weakest trees. In a healthy forest, older trees share their wealth of nutrients with younger, vulnerable trees. A tree growing in a disadvantageous environment will be compensated, like the shaded fir seedlings in Simard’s experiment that received more carbon from their fellow seedlings that had greater access to sunlight. We know now that in order to properly observe a tree and the scope of its needs, we have to look at the ties it forms with these fungal highways and other trees.

Professor D’Amato explained, “we’ve just grown to recognize over the past several decades that ecosystem ecology and ecosystem management has become a big part of how

we manage forests, that forests are complex, and so when we’re managing them we want to be maintaining these complex dynamics that are out there, through managing for dead wood, managing for species that aren’t going to make a good saw log, but make a really great habitat, or really good for sustaining mycorrhizal symbioses.”

Merlin Sheldrake is a biologist who studied fungal networks in Panama’s tropical forests. He wrote the book Entangled Life, the first book I ever read about fungi and their far-reaching influences. The book focuses on relationships and how they blur the borders between ostensibly separate

organisms. While discussing the connections between mycorrhizal networks and the agriculture and forestry industries, Sheldrake muses that “where the person’s self begins and ends is not as straightforward a question as it might seem at first glance. Mycorrhizal relationships challenge us with a similar question.” They demand a broadened view of life. They transfer water, carbon, phosphorus, nitrogen, and information in the form of electrical signals. They fortify plants against drought, disease, salinity, and attacks from insects. They increase the amount of water that the ground can take in, prevent nutrients from washing out of the soil, and will even physically hold soil together. This eases a burden on our climate, as most of the carbon in northern temperate forests is stored in soil and transferred to the fungi. In fact, these fungi are responsible for four percent of atmospheric carbon sequestered annually. Fungi

are important coordinators of life within a forest; it is impossible to comprehend the full picture by considering a tree in isolation from its community. The way that trees use these relationships to share and receive from other members of their environment, based on their needs and ability, is a mutually beneficial system and a reason why forests survive to develop into healthy ecosystems.

Individual trees in a forest cannot survive without one another or the networks that facilitate their connections. This statement challenges the ideals that we use to categorize things in nature, and in our own society. According to Darwin, the weaker members of species die, while the strong survive to pass on their genes, and thus the fundamental law of nature is competition between individuals. Where does a tree end? Where does a person? Although we consider ourselves advanced, humans rely on the patterns we observe in nature to make sense of ourselves.

In the United States, we have mirrored Darwin’s rule and turned it into an economic and social regime. We think of ourselves as competing for limited resources, and the only way to win is to push one another out of the way to take as much as we can, but the “natural phenomenon” that inspired this thinking was never as pervasive as we believed it was. We do not have to abide by outdated ideals of self-interest because we are starting to realize how difficult it is to define the ‘self’ in an interwoven world.

The “survival of the fittest” approach needlessly leaves

people behind, and it deprives everyone of the community that would fortify them. Cooperation is a far more effective tool for survival than cut throat rivalry. I am not myself without the scientists that I look up to like Read, Simard, and Sheldrake. They are not successful without using each other’s contributions to aid in new discoveries. A tree is not just a tree, and when you go walking in the woods, you are stepping into a collaborative community. In our society of limited resources, I wonder what we would become if we formed our own networks of mutual compassion. H Art by Maya Kagan