When we go to the forest, we usually find peace in the stillness of nature. However in reality, underneath our feet is an entire network that is sending and receiving messages all day. It’s called the wood-wide web, a network for trees to communicate using fungi.
These fungi are called mycorrhizal fungi, and they live in the roots of trees and plants. Fungi are a big part of trees, and they coexist with the trees in a mutually beneficial relationship.
Types of fungi that live with trees are molds, mushrooms, and yeasts. Although some fungi may look like plants, these appearances are deceiving. We currently believe that fungi first appeared in the Paleozoic period around 300 million years ago, and they now make all organic organisms decompose and disappear.
Fungi are essential to plant survival. They have hair-like filaments called hyphae in the soil, which pump water more effectively than the tree’s roots.
Mycorrhizal fungi use acid to melt holes into rocks and suck out nitrogen and phosphorus. In return for the fungi’s work for the trees, the trees provide the mycorrhizal fungi with sugar, which they create through photosynthesis. 20 to 80 percent of the glucose that trees make goes to their fungi neighbors.
Trading minerals, water, and sugar for their host trees is not all that the mycorrhizal fungi do. They form massive networks of fungi threads called mycelium, and these threads can extend through thousands of acres and connect entire forests. Older trees have more complex fungi networks, and younger trees develop and expand their network as they grow older. These networks act as roads that ship chemical currencies, and the fungi act as tiny sugar storage holders for the trees if they need a boost.
What is even more amazing about these networks is that if a tree is dying, it can release its extra glucose into the wood-wide web. Nearby trees are able to inherit this glucose, even if the tree is a different species.
Trees can also use the networks to send warnings. Suppose an insect or parasite bites into a tree. The tree can then send a chemical message through the underground network, which warns trees deeper in the forest that there is a danger and insects are eating the leaves. In response, the trees produce bitter compounds that make their leaves tasteless to the insects.
However, these networks aren’t always used for good and helping each other; they can be misused to harm fellow trees. Some trees use the web to spread chemical attacks to sabotage other trees that attempt to grow too close. Trees can use the network to go to war with a tree that invades its territory.
Fungi networks make one question what’s going on right beneath one’s feet and how there is an entire world underneath us that humans can’t see.