It is quite a profound question. We have to begin with the definition of “language.” By language, we usually mean “meaningful sounds produced by the human speech apparatus (the throat, oral cavity, larynx, tongue, palate, teeth, nasal passage, etc.) that are capable of expressing thoughts.” In simple terms, language is a medium of exchanging ideas. Whatever we use to express our thoughts is language.
Can there be language without a speech apparatus? Certainly. We can convey messages to others through gestures, sounds, light, electricity, writing, and more. These messages themselves form language. But is language exclusive to humans? In other words, are humans the only creatures on Earth that know how to use language?
It can be said with certainty that members of the animal kingdom communicate with one another. In scientific terminology, this is called “cross talk.” One cell communicates with an adjacent cell through cross talk.
Insects, fish, animals, birds, and even trees communicate with each other. Creatures that cannot produce sound, that lack a nose, throat, or tongue, still exchange information. The means of communication may include silent movements, changes in body parts, the release of chemical substances, or the use of electrical signals.
Scientists today are deeply curious about the language of trees. Modern research has revealed that trees can exchange information among themselves in special ways. We once believed that trees, rising from the dark depths of the soil toward the call of the sun, were mute and deaf. But recent findings have changed that view. Trees, often considered among the earliest forms of life, can express pain and distress. They maintain communication with one another, using electrical signals and certain odor-producing chemicals as their medium.
Communication through smell is quite familiar among two-legged and four-legged animals. A tiger, for instance, marks its territory by spreading scent (pheromones). Plants, too, can produce strong chemicals and release their scent to drive away enemies. An example will help illustrate this, but first, another point.
What kind of chemically driven communication system do plants use? Trees use several volatile organic compounds (VOCs) to send signals. These include mainly four types of chemicals: fatty acids, benzenoids, amino acids, and terpenoids.
There are many examples of how trees defend themselves using chemical substances. Consider an incident from a safari park in South Africa. Giraffes were feeding on the leaves of acacia trees. These tall trees are a favorite of giraffes. But the feeding was relentless. Losing too many leaves threatened the trees’ survival. The trees needed to drive the giraffes away. What did they do? They began producing toxic substances in their leaves. Tannin, a compound already present in the leaves, increased in concentration, making the leaves more bitter. At the same time, the trees released ethylene into the air. When nearby acacia trees detected this ethylene gas signal, they too rapidly increased tannin production in their leaves.
Plant processes generally occur slowly, but sometimes they can act quite quickly. By producing chemical compounds, trees can protect themselves for a period of time. They must endure attacks from many insects. By recognizing the chemical nature of an insect’s body fluids, plants produce specific chemicals to defend themselves. In some cases, they even release compounds that attract beneficial organisms.
Plants can also send electrical signals in addition to releasing chemicals. When a tree is injured or struck, its tissues transmit electrical impulses. If one part of the tree is in danger, the message reaches other parts. In response, leaves may produce particular chemical compounds, effectively preparing a defense system. Some trees store toxic, intensely bitter substances in their leaves, which can kill insects that attempt to eat them. Neem leaves are a good example. Many plants also store salicylic acid in their leaves and stems, which is useful to humans and helps protect the plant from insect attacks.
Not only leaves, but roots also transmit warning signals. Fungi attach themselves to the tips of roots. These fungi are not the same as plant cells; they live in the soil. Underground, they form networks connected to plant roots. Through this network, one tree can send danger signals to another. Once the signal reaches a neighboring tree, it too begins producing and releasing toxic chemicals.
Tree roots spread deep and wide beneath the soil. With the help of fungal networks, trees maintain communication among themselves. Modern research has also shown that when a tree becomes weak, its ability to defend itself and communicate decreases. As a result, insects tend to target such weakened trees.
Research on the language of trees is ongoing and continuous. New information is emerging almost every day. This raises an important question: can we still call trees “mute”?
Earlier, the plant world was thought to be static, deaf, and silent. Today, that idea has changed. We now know that trees are dynamic. Although they do not speak through sound, they send messages in different ways through chemicals, electricity, and fungal networks. By sending these messages, they not only protect themselves but also warn neighboring trees of impending danger. Extensive research on the “language of trees” continues, and soon many hidden secrets of the green world will be revealed.
