This exploration of the wonders of plants was first presented to the Unitarian Universalist Congregation of Glens Falls in Queensbury, New York, on October 5, 2025. The talk is balanced between science and spirituality and is appropriate for most audiences.
The first time I went to a state wildlife rehabilitation conference, the keynote speaker was some guy named Doug Tallamy. The conference program said he was an entomologist, so I figured he was going to talk about bugs. He did, but he also talked about trees. I came home from the conference with a deep dislike of Bradford pears and an equally deep reverence for oak trees.
I’ve always been more fauna than flora, but hearing about how oaks support so many other species, caterpillars to squirrels to blue jays, sparked my interest in ecology, both the science-y and spiritual sides of it. Since then, I’ve been on a native tree planting kick, and I’ve grown in my understanding and appreciation for trees.
There’s some pretty wonderful stuff I’m going to share with you about trees, but there’s also a sad reality. Globally, we’re cutting down 15 billion trees a year, and losing forest at the rate of something like the land area of Portugal annually [1]. I believe the trees are victims of a story humans have been telling themselves about who’s “better” on the evolutionary scale. Plants are definitely not like animals and scientists and philosophers have been putting them on the bottom since Plato. It’s cultural, this oppressive conceptual framework that has been used to justify the domination and exploitation of the plant kingdom. And it sticks, even though both science and ecospirituality are currently questioning that paradigm.
I probably can’t put a stop to the logging today, but maybe something I share will stay with you, so you can be part of telling a different story about plants. I should probably start, though, with a little more about Doug Tallamy.
If you don’t know the name, you might know the movement he helped found, Homegrown National Park, promoting native tree planting in every backyard. Tallamy is a professor at the University of Delaware and, as I mentioned, an entomologist, as well as an ecologist and conservationist. He wrote several books, too. Tallamy did a fascinating study of the moth caterpillars that lived an and ate an oak tree in his yard. He found 245 species of moth on that one tree, 27 of which he knew would only live on oaks. Now we’ve been told, mostly by those who sell pesticides and tree service, that having caterpillars eating a tree is a bad thing, but here’s the thing. What I learned from Doug Tallamy’s keynote is that those caterpillars are important food for birds. So, when we spray to save trees, trees which are, by the way, well adjusted to some chewing on by the caterpillars, when we spray we’re also eliminating food for birds, other insects, and even some parasites that would naturally keep the caterpillars in check.
I mean, if the number of mosquito bites I had in the spring was any indication, bugs seem like they’re still plenty abundant, right? But insects are down by 45% since the early 80s. It’s probably not a coincidence that we removed half the forests during the same time period. I’m going to circle back to Tallamy, the critical link between plants and insects, and oak trees in particular, but there are wonders to be considered before then.
I’m going to start at the top. The top of the trees, that is, because that’s where the leaves are. That’s the part of the tree that eats light. Now maybe you don’t think plants can eat light, and if you expect plants to do things that humans do in the same way we do them, you probably wouldn’t call photosynthesis eating. But consider that what we and all the other animals are trying to do is take in something we call food, apply a chemical process to break it down and get some glucose, the sugar, and then use that glucose to fuel other things in the body, then plants are definitely eating, like us. And not like us.
Zoe Schlanger, author of The Light Eaters, explains plant eating like this: Plants draw water up from their roots and capture carbon dioxide through tiny pores on the undersides of their leaves. They absorb light, which is energy, through their leaves, too, and that energy tears apart both the water and carbon dioxide molecules. Half the oxygen gets released and gets used by animals in a handy process we call breathing. Six molecules of carbon dioxide and six molecules of H2O release six molecules of oxygen and one very precious molecule of glucose. The glucose is used to make more leaves, which in turn provide more glucose, and is sent down into the roots so they can grow, which means they can bring in more water [2]. Maybe you get the science, but consider this: plants, through photosynthesis, take non-living elements, air, water, and light, and turn them into food for themselves and food for the rest of the living world. And some medicine, too. Whatever you ate today either is a plant, is something that ate plants, or something that ate something that ate plants. We can’t swallow inanimate elements and turn them into food just by standing in the sun. We are absolutely, totally dependent on plants to do that for us.
Now I want to get to the root of things. Well, the roots of trees, because some really interesting stuff happens there. I mentioned that tree roots draw water out of the soil and send it up to the leaves for photosynthesis. But down there is also an amazing communication network thanks to a special relationship between trees and mushrooms.
What we call mushrooms are really the fruit of fungus, the part that’s above ground. Most of a fungus lives in the soil, intertwined with tree roots. Tiny threads, called mycelium, wrap around or bore into the roots of trees and, essentially, connect trees together. It’s called the mycorrhizal network or, by some, the wood-wide web. The mycorrhizal network is used to transfer water, nitrogen, carbon, minerals, and that precious glucose, between plants. Older, taller trees send nutrients and sugar to saplings growing in the shade so they can grow. They may even, according to one study on Douglas Firs at the University of Reading in the U.K., be able to recognize the root tips of their relatives and favor them when sharing nutrients.
It’s very nice of the fungi to provide this service, but they don’t do it for free. The fungi get a steady source of carbon as payment, plus they keep about 30% of the sugars for their own growth, useful since they can’t produce their own. Fungi can collect nutrients, though, and absorb phosphorus and other minerals from the soil, which they share with the trees. It seems like a win-win, the fungi-tree cooperation.
As trees get older, they develop more fungal connections. Their roots go deeper, where they can reach more water to pass on to their saplings, and are even thought to be able to detect the ill health of neighboring trees and send nutrients to help. These trees are known as hub trees or, my preferred name, mother trees.
Now I have to say this is not set science. It’s very difficult to study mycelium networks. When you dig up a tree’s roots you kill the fungus you want to study. And there are other pathways that might be involved, like pores in the soil and direct from tree root to tree root. And I’m okay with there still being some mystery around this. That’s where the spiritual part comes in. I feel awe just thinking about how much we don’t know about things like mycelium. And the idea of a network of cooperation kind of upends the whole survival of the fittest thing. If it was a case of individual selection, trees would use resources in a way that benefitted only them, not the group of trees and other organisms in the area. If that was the case, there would be no mixed wood forests. There wouldn’t even be any groves of a single species. Instead, trees are having these conversations and taking care of each other, increasing the resilience of the whole community.
Expecting trees to be competitive is a problem of human understanding. We want to see other forms of life as models for our human behavior, which is based on our societal values. But trees just aren’t like that.
Can we ever understand what trees are thinking? Probably not. But it’s an interesting thought experiment to consider the motivations of those we’ve put down at the bottom of the evolutionary ladder. Can plants have intentions? How about fungi?
I once took a plant shamanism workshop with the controversial herbalist Susun Weed. After a shamanic journey during which I had a lengthy conversation with a bush in a planter about the meanings of freedom and movement, there was some Q&A. Someone asked about mushrooms and why so many were poisonous, and Weed said something that just stuck with me. She said, “Mushrooms are toxic because you’re no good to them until you’re dead.” Let me tell you, I’ve never looked at a mushroom the same way again. But she’s right, in a way. Fungus feeds on dead stuff. And that’s where some of the things fungus shares with trees comes from. And we think we’re in charge. Ha. All the mushrooms are out to get us. Really, though, they can wait.
Anyway, human motivation, in the western industrialized world anyway. is different. We can’t wait. It’s all about how many resources we can extract today so everything is productive for our benefit. When it comes to trees, we want forests full of trees that can be used commercially, like pine and maple. The trees that don’t suit our needs, like aspen and birch, get taken out. So even when the loggers replant, they are just planting monocrops, not restoring the once biodiverse and vibrant plant ecosystems. And they take the big mother trees, which can collapse the whole forest. If the mother trees are still there, they can help the forest heal itself by supporting new growth. When they are cut, the mycorrhizal network disappears and nobody thrives.
Now I’m using the collective “we,” because I know you relate differently than most to the natural world, but we are part of a system that extracts and exploits, not just other species but our fellow humans, too. We, western society, have a problem with leisure. There can be little to no time, except maybe when we’re sleeping, that we aren’t productive. Even when we aren’t at our jobs we have things to do to keep up the house and yard, right? And a lot of that, when you think about it, is stuff like mowing our monoculture lawns, blowing the leaves, and spraying the caterpillars in the trees.
Which brings me back to Doug Tallamy. And some things I learned about oaks from him. I mentioned they host many species of moth caterpillars, which are an important food source for birds. There’s also the acorns, which feed squirrels, of course, but also deer, wild turkeys, and jays. We think squirrels do a lot of the planting of oaks but blue jays also cache acorns by burying them, and effectively plant more than three thousand oaks a year, each. And flying means they have larger territories than the squirrels. Jays helped the oaks spread around the earth faster than any other tree species. And everyone eats well.
Oaks are also saving us from flooding. A two-inch downpour, which amounts to about 54 thousand gallons per acre, can be almost entirely captured by oak forest leaf litter and the humus created by it, then it slowly releases it into the water table. Without that leaf litter, the same rainfall would cause a flood. The soil pores also filter the water so it’s clean by the time it reaches the water table.
As oaks age, their inner xylum tissues break down, resulting in hollow spots in their trunks. A hollow trunk isn’t a sign that a tree has to come down. Instead, it’s just normal aging in an oak tree. And the hollows provide homes for rare fungi, racoons, opossums, squirrels, who, by the way, have more success raising babies in the hollows than in their leaf dreys. The hollows also house bats and, sometimes, bobcats. Oaks support their ecosystems with more than just food, it seems.
I talked about the mycorrhizal fungi. Oak roots have extensive relationships with them. The fungi put carbon into the surrounding soil where, if not disturbed, it can stay for hundreds of years. Which is nice, because that means it isn’t in the atmosphere. And they have relationships with other trees, too. In forests, trees interlock their roots in this continuous matrix, making it difficult to uproot any of them, even in extreme weather, which probably comes in handy since we, unlike the trees, keep putting more carbon into the atmosphere.
Why am I telling you all this about oak trees? Well, to quote Tallamy, “We cannot casually accept the loss of oaks without also accepting the loss of thousands of other plants and animals that depend on them” [3]. Elaine Miller, a professor of philosophy at Miami University in Ohio, wrote, “There is a grave danger in the fact that nature has been appropriated by an approach that seeks to harness and utilize it without recognizing that loss such a process involves” [4]. It’s going to catch up to us humans eventually.
So, what do we, ecologically aware spiritual people that we are, what do we do? We plant oaks and other natives. That’s what Homegrown National Park is about. There isn’t too much “over there, out there” left to conserve, not when a Portugal’s worth of forest disappears every year. But there are suburban backyards, golf courses, urban parks, places reclaimed from mines and dumps, where we can plant oaks and other native trees and allow the natural cooperation to restore the land. That means, though, that we have to learn to coexist with more-than-human species, including the trees.
What I hope you’ll do, though, is absorb some little bit of what I shared today. Maybe you’ll remember that insects need trees, and birds need insects. Maybe you’ll think about how plants eat light, and how we breathe because they do, and eat, too. Or you have some new wonder about the mycorrhizal networks, the wood-wide web. Or you’ll remember that hollow oak trees are just aging gracefully. And you’ll tell the story of how trees cooperate, how they help each other grow and create resilient forests, where all beings thrive. Plants aren’t like us. We don’t have the kind of magic that turns water, air, and light into food. But they do, and they share it with us. And that’s pretty amazing.
References:
- Hannah Ritchie (2021) – “Deforestation and Forest Loss” Published online at OurWorldinData.org. Retrieved from: ‘https://ourworldindata.org/deforestation’ [Online Resource]
- Schlanger, Zoë. 2024. The Light Eaters: How the Unseen World of Plant Intelligence Offers a New Understanding of Life On Earth. Harper, an imprint of HarperCollins Publishers.
- Tallamy, Douglas W.. The Nature of Oaks: The Rich Ecology of Our Most Essential Native Trees. United States: Timber Press, 2021.
- Miller, Elaine. “Disseminaion, Rhizomes, Efflorescence: The Legacy of the Vegetative Soul in Twentieth-Century Thought.” In Vegetal Entwinements in Philosophy and Art: A Reader, edited by Giovanni Aloi and Michael Marder. The MIT Press, 2023.