Wait, plants could talk?

When my team and I worked with theater actors, we learned a concept called subtext. Subtext is what is really going on underneath what is being said or what is being played out in a scene. It is what you really hear in your head that is different from what is coming out of your mouth or being expressed by your gestures. Knowing that, imagine a whole different scene of stories being played out by the subtext in each of our heads when we interact with one another – a dramatic collective of subtext that defines who we are as belonging to a family of humans.

Now think of plants. From where we view them, they are these upward, sometimes sprawling, sometimes just shooting straight up living things. Some of them are giants, while some are of human-friendly heights. When I was in school, trees were about growing “up,” and aside from the perfunctory mention of the roots that get nutrients from the soil to make trees grow, much of the story about trees was about “up.” Even in the famous poem by Joyce Kilmer, it is “a tree that looks at God all day,” that is, towards the sky. I think this is because we humans tend to think that what we see is all there is. We know that plants need sunlight from “above” to be able to do its job – mix light with nutrients it gets from the soil – to produce sugars. But “up” is the tree’s “script” in nature. It is part of it, but not all of it. They are what we see. The subtext is literally underground – the understory. And these are not just the roots. 

Each tree or plant has roots that are linked via networks. Like how fiberoptic and underground cables link the internet, these networks are formed by fungal roots called mycorrhizas. These mycorrhizas have threads called mycelium and their other parts are visible aboveground as mushrooms. These fungi conquer the roots of trees to form a relationship where the fungi and the tree benefits. The mycelium is sort of like the extension of plant roots, as mycelium threads creep throughout the soil, coating every soil particle to extract water and nutrients that they can give to the trees. The network is so intricate and dense that like your intestines, a single square foot could be stretched into hundreds of kilometers. The trees, in exchange, give fungi sugars that the fungi cannot produce by themselves because they are not capable of photosynthesis. Fungi do not know what to make of light. 

Since mycelium threads reach out in all directions, they connect all plants with each other. And this is how plants communicate – in secret. This is no creative interpretation, but science fact. This was revealed by fascinating, laborious experiments by Susan Simard, an expert on forests. In her charming and enlightening TED Talk, she talked about why “communication” is really the word to describe what plants do via their understory network.

She said that the whole scenario underneath is not just about resource exchange and an interplay of nature-defined roles. It is also about signaling other plants when harm is present or – get this – even when recognizing kin! Yes, plants do show a preference for plants belonging to their “tribe.” Nepotism is everywhere in nature. (READ: Plants talk (really) but are we listening?)

As a network, there are “hubs,” Simard explained, and these are the “mother” trees that have extensive mychorrhizas. She did an experiment where she saw that mother trees do send more carbon to their own seedlings underground than they do to other connected seedlings in the network. The mother trees even send hormones and defense signals, boosting their own seedlings’ chances of survival. But even between different species, Simard found that the trees can send each other what they need, depending on the season. Her often cited case is that of the fir and birch trees. During summertime when the Douglas fir becomes shaded, the birch tree gives its excess carbon to the fir and in the fall, when the fir has excess carbon, it goes to the birch tree. 

So cutting a forest is not just about losing trees which would have supplied us with oxygen and would have kept the carbon that human activities keep releasing and which causes dramatic climate change. That is just a part of the story of what plants are all about. They have a planet within our own planet, and that planet is keeping us alive! Losing plants in a massive scale such as when we decimate forests is literally pulling the ground from underneath us!   

Lose a mother tree, and we lose the mycorrhiza network that embraces it. Then we lose the protection it gives to its seedlings and other trees. It is like a library of life where the topics are all connected. Then we lose the books in the library of life one by one. Having only a few kinds of trees is having only a few books and calling it a library and demanding from it the nourishment and complexity that only a diversity of books could give.

So the next time you ever encounter a plant or a tree, look up, but then, also look down. Be aware of the buzz of life everywhere underneath your feet which extends everywhere, beyond where you and your tree stands. That is how we should always look at nature – not in pieces, but as a whole, connected. So yes, indeed, poems about trees are made by fools, but thinking that trees are optional for life is not only dumb – it is also suicidal. – Rappler.com

Maria Isabel Garcia is a science writer. She has written two books, “Science Solitaire” and “Twenty One Grams of Spirit and Seven Ounces of Desire.” You can reach her at sciencesolitaire@gmail.com.