For centuries, we viewed forests as quiet, passive collections of individual trees competing for sunlight and resources. But recent scientific discoveries have revealed a breathtaking secret: forests are bustling with communication. Below the ground, trees are engaged in a complex social network, sharing information and resources in ways we are only just beginning to understand.
The foundation of tree communication is a vast, intricate underground network of fungi. This symbiotic relationship between tree roots and fungi is called a mycorrhizal network, but it’s more excitingly known as the “Wood Wide Web.” It functions like a biological internet, connecting not just trees of the same species but entire, diverse forest communities.
Fungi cannot produce their own food through photosynthesis. Instead, they attach their thin, web-like threads, called mycelium, to the roots of trees. The trees provide the fungi with carbon-rich sugars produced during photosynthesis. In return, the fungi act as a massive extension of the tree’s root system, exploring the soil and absorbing vital nutrients like nitrogen, phosphorus, and water, which they then transfer to the tree.
This network isn’t just a simple trade. It’s a dynamic superhighway. A single mature tree can be connected to hundreds of other trees, creating a complex web that allows for incredible levels of interaction. Ecologist Suzanne Simard, a pioneer in this field, discovered that older, more established trees act as central hubs, managing the flow of resources throughout their community.
One of the most stunning discoveries is that trees use this network to warn each other of danger. When a tree is attacked by pests, such as aphids or leaf-eating caterpillars, it doesn’t just suffer in silence. It initiates a defense response, producing chemical compounds to make its leaves less palatable or even toxic.
More amazingly, it sends electrochemical distress signals through the mycorrhizal network to its neighbors. Receiving this early warning, nearby trees can ramp up their own defenses before the pests even arrive. This proactive community defense greatly increases the forest’s overall resilience.
Communication also happens above ground. When attacked, some plants release airborne chemical signals called volatile organic compounds (VOCs). A classic example is the acacia tree in the African savanna. When a giraffe starts to eat its leaves, the acacia not only increases the tannin levels in its own leaves to make them bitter but also releases ethylene gas into the air. Nearby acacia trees detect this gas and immediately begin producing more tannins, preparing for the approaching browser.
Dr. Simard’s research also uncovered the profound role of what she calls “mother trees.” These are the largest, oldest trees in the forest, acting as the central hubs of the network. They are connected to hundreds of other trees and play a crucial role in nurturing the next generation.
A mother tree can identify its own kin, or its seedlings, growing on the forest floor. Through the fungal network, it sends them more carbon, nutrients, and water than it sends to unrelated seedlings, giving its offspring a significant head start in the competitive forest environment. When a mother tree is dying, it doesn’t just hoard its resources. Instead, it begins a process of “dumping” its carbon and defensive signals into the network, a final act that provides a massive boost to the surrounding community and ensures the health of the next generation.
This discovery challenges the old idea of forests being solely about competition. It reveals a deeply cooperative system where the strong actively support the weak, and the community’s health is prioritized.
The field of tree communication is constantly evolving, revealing even more layers of complexity. While the “Wood Wide Web” is now well-documented, scientists are exploring other potential communication methods.
These discoveries are fundamentally changing how we manage and protect our forests. Understanding them not as collections of individual timber resources but as complex, interconnected superorganisms is vital for conservation and reforestation efforts.
Do all trees communicate in this way? Most, but not all. The vast majority of plant species, including most forest trees like firs, birches, and pines, form mycorrhizal relationships. However, some families of plants, such as the cabbage family (Brassicaceae), typically do not form these connections.
Can we listen to trees talking? Not in the way we think of “talking.” The communication is primarily chemical and electrical. While we can’t hear it with our ears, scientists can measure the electrochemical signals and analyze the chemical compounds being exchanged to interpret what is being “said.”
How does this change our view of forests? It shifts the perspective from a model of pure competition to one that includes immense cooperation and community. It shows that forests are intelligent, resilient systems that actively manage resources, defend themselves, and nurture their young, forcing us to see them as living communities rather than just scenery or resources.