Trees Feel: The Line Between Plants and Animals Is Thinner Than You Think
Did you ever ask yourself about the complexity of trees?
When you look at a forest, what do you think? What do you see? A large group of diverse wooden bodies — old or young, with trunks wide or thin. Large canopies that block sunlight or specimens with pointy branches and fewer leaves.
However they may look, one fact is certain: they are trees. Below, you see grass, moss, flowers, and bushes. All plants. Plants — are they alive? Absolutely.
But do they know they are alive? That is a fascinating question we only recently began to ask.
Why want to question nature?
Simplicity is something we often take for granted. If something seems simple, most think digging deeper is a waste of energy. Let’s be glad scientists are not most people.
Ecosystems are complex. We lived in the dark for so long about them that we can’t even grasp how much we don’t understand.
Would you believe trees are all connected? They create communities, helping each other and signaling threats. Their roots form a network that reaches far and wide.
Like the internet. Or, as scientists call it: The Wood Wide Web
Trees are very slow in everything they do. They grow and react in slow motion — by our standards. But nobody, not even trees, likes sluggish internet.
Their network needed its own optic fiber: enter fungi and their mycelium. The thin mushroom roots travel through the soil, easing connections between trees. They also provide nutrients, such as nitrogen, in exchange for glucose.
Ok, but what about the senses?
I hear you. Even if trees are connected, that doesn’t mean they have senses. So, case closed, right? Not really.
Scientists decided to look closer once again. Their discoveries are intriguing — and they might change our view of the world.
How trees “see”
Similarly to us, plants have photoreceptors. These cells detect light and direct biological mechanisms accordingly.
Information about light intensity comes from phytochromes (red and far-red receptors) and phototropins (blue light receptors). With their help, trees can orientate away from shade.
Notice how they only pick up and process red and blue? That’s why leaves are green — it is the only hue that gets reflected for us to see.
Plants also have Circadian Rhythms: internal biological clocks in tune with the external environment. We use ours to know when to sleep — jet lag is their fault. For trees, they regulate flowering, leaf movement, and metabolic activities.
How trees “smell”
Wait, what? Surely, that can’t be true.
We all knew about photosynthesis — sight may have made sense. But smell?
Trees need to know when insects attack them in order to defend themselves. To do this, they sense Volatile Organic Compounds (or VOCs). These substances are released when a tree is in distress. So, what do they imply?
When a tree releases VOCs, other trees can pick them up through the air — so, they smell them. The neighboring trees then produce substances that can impair or kill the insects. In short, they prepare for a potential attack.
We’ve seen this happen with larger predators as well. A study conducted on the behavior of Giraffes saw that after feasting on a tree, they didn’t choose another one nearby. Instead, they traveled to trees farther away, which wouldn’t have gotten the distress signal yet.
That way, the Giraffe could eat fresh, sweet leaves all day — without ever tasting the sour defense substances produced by the trees.
Some plants sense touch
Have you ever heard of Mimosa Pudica? No? Let me introduce you to the plant which hates being touched.
Climbing plants, such as vines, also detect touch. That’s the way they grow around objects.
How do they do it, I hear you ask?
They have mechanoreceptors, specialized cells that detect mechanical stress. These cells often work through ion channels that open or close in response to mechanical forces.
Another help is electric signals. They are similar to animal nerve impulses and react to mechanical stimuli. These signals travel through plant tissues to initiate responses such as leaf folding.
Can plants also “hear”?
You’ve probably heard it before: plants react well to classical music. Is it true?
Sadly, we’re not sure. While yes, plants have been shown to react to sound vibrations, that’s where scientific proof stops.
Some frequencies can enhance seed germination, root growth, and overall plant health. But we can’t directly correlate that to different types of music or human voices.
I know, you wanted your house plant to love Mozart as much as you do. Maybe one day.
What if they could speak, too?
That’s right. Some scientists think plants can “speak” to each other. Not with words, of course.
They use ultrasonic vibrations. In simple terms, high-frequency sounds we can’t hear. So, how do we detect them?
Researchers use specialized equipment, such as contact microphones and acoustic sensors. These tools can capture sounds made by plants during water transport and stress responses.
Bioacoustics is an emerging field, but it could be helpful. Imagine if we could hear thirsty plants — agriculture would be a breeze.
What else is there?
We’ve talked about plants being able to sense their surroundings, but there’s more. In science, there’s always more.
The facts in this article may be reduced to rather simple physics or chemistry. But there is something else, much more fascinating, that we’re only beginning to grasp.
That, however, is a story for another day.
Until then, be nice to plants. They might sense and remember you.
The information in this article is inspired by Peter Wohlleben’s fascinating book “The Hidden Life of Trees: What They Feel, How They Communicate — Discoveries From a Secret World”. I highly encourage you to read it, since it covers even more captivating facts than I could fit here.
