The Internet of Trees: Here's how trees talk to each other
Dogs bark, lions roar, birds sing, whales whistle, humans speak and tree. Do trees communicate? Well, they ‘chat’ with each other through a complex underground network made of mycorrhizal fungi. Trees rely on this network to communicate and gain knowledge just as much as we rely on the internet! No wonder scientists call this fungal network the Wood Wide Web. Want to know more? Read on.
Give and take
Trees and mycorrhizal fungi share a fascinating symbiotic relationship. Symbiosis, as you all know, is a close, long-term relationship between two organisms. In this case, it is mutualistic symbiosis, as the association benefits both the organisms involved. Here’s a sneak peek into the process of symbiosis for you.
Mycorrhizal are thread-like fungi that live on or around the roots of trees. They form an extensive network in the soil connecting neighbouring trees. Since fungi cannot produce their own food, they rely on trees for fatty acid and sugary meals, the products of plant photosynthesis. In return, they transfer nutrients (such as phosphates and nitrates) and moisture from tiniest pores within the soil to the plants via their root-associated network. This underground fungal network is known to extend for many miles and thus vastly expands the area that plants can draw sustenance from and withstand drought. Studies have found that certain stressed and dying trees can even pass resources to their neighbours before they die. The fungi’s gestures of gratitude do not end there. They also help plants transmit messages to one another.
What kind of messages are these?
More often than not, these are messages of warning. When a tree is attacked by insects, it will release certain chemicals that travel through the fungal network and warn other trees of the danger. By having an early warning, other trees are able to protect themselves better. For instance, a tree may alter its biochemistry by increasing the levels of toxins in its tissues in order to deter pests. Strange are the ways of nature, it seems!
Beyond words
Communication between multi-cellular animals usually involves neurons. But fungi lack a nervous system. In that case, how is communication possible? Well, they have something remarkably similar. Instead of neurons, they have what is called hyphae. These thread-like filaments form a thin web called mycelium which links fungal colonies within the soil.
Scientists recently mapped the complex system of mycorrhizal fungi and found that language-like electrical impulses were being transmitted along hyphae. As part of the study, scientists used tiny electrodes to record the rhythmic electrical impulses transmitted across the mycelium of four different species of fungi. They found that impulses vary according to amplitude, frequency and duration. By drawing mathematical comparisons between the patterns of these impulses with those more typically associated with human speech, scientists suggest they form the basis of a fungal language comprising up to 50 words.
The complexity of the languages used by the different species of fungi seemed to differ. The number of electrical impulses travelling through hyphae increased when fungi encountered new sources of food. Scientists believe it’s possible that fungi use this “language” to let each other know about new food sources or injury. They may be using a different language to share information about potential sources of danger. The impulses are believed to travel across network, connecting even distant trees.