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How trees communicate by Suzanne Simard. Can you remember when you were a child and you wondered whether your toys came to life when you went to sleep? As an Arborist I have had similar thoughts about trees and the forest. Do the trees all start having a big chat when I’m not around, just like in a Lord of the Rings book? Well it turns out, in the case of trees at least, that this does happen. And not just when your back is turned. The forest is alive with communication.
This post will shed some light on how and why trees communicate with each other.
When you first look out at a forest landscape it is easy to describe what you see as a collection of individuals, each preoccupied with advancing its own interests, and competing with its neighbor. We have this Darwinian idea that the whole forest is one big race for survival, each tree out for themselves. This is only in part true. Competition does exist, but so do does cooperation. Research has shown that trees and plants actually work together so that the forest system as a whole survives and flourishes.
The above ground part of a tree that is most apparent to our observation is only a tiny part of what is going on in the forest. Under the ground thousands and thousands of kilometers of roots weave their way around in a massive interconnected network. This network is further enhanced by fungi (mushrooms). These too have roots which surround and bond with the roots of the plants, greatly increasing the magnitude of this network. You could almost imagine the whole thing like the internet for trees and plants.
It is via this network that communication takes place.
It has been known for a while that trees and fungi have a symbiotic relationship, the fungi adding their roots to the system to help the trees absorb more nutrients and the trees sharing some of what they obtain with the fungi. However, more recently it has been discovered that trees also share with each other. Experiments were performed and the results showed that trees growing together shared many types of nutrients with each other. Communication was two way, with the levels of nutrients varying throughout the year depending on which tree needed more. It was found that trees of different species even communicated with each other. It was also found that trees could recognize their individual offspring in the forest and provide them with more nutrients so that their genes had a greater chance of surviving.
Communication was not only in the form of nutrient exchange. Also warning of predation or attack by pests and diseases. Trees that were being grazed could tell others so that they could withdraw tasty nutrients from their foliage making grazing less attractive. Messages to strengthen defenses against infections were also detected, enabling trees to prepare themselves before an attack took place. It is thought that this has come about because trees need each other for survival. It’s the whole ecosystem that must survive for any of the individuals to have a chance. By working together in this way, the likelihood of passing on genes that will be successful is greatly increased, ensuring a favorable environment for the future.
This mirrors cooperation in our own society and by how working together we can overcome common challenges.
This information can really change how we view trees and the forest environment. It highlights the need to conserve old forest and think carefully about how we manage timber harvesting in order to leave an ecosystem that is still intact and healthy. Leaving some of the older trees on site is vitally important so that they can nurture the younger trees and increase their chances of successfully reaching maturity.
Anyone wishing to learn more about this topic should watch the following TED talk from Suzanne Simard