Trees, and plants in general, to me have always been the start of a much more interesting ecosystem. They are the heterotrophic instigators of nature, using the power of the sun they can make sugars and this basically gets everything going. Above that they seemed uninteresting. However, I listened to a fascinating episode of RadioLab called “From tree to shining tree” in which the details of the Wood Wide Web were unravelled into my ears. These organisms are not solitary sugar factories but part of a vast interconnected system. Below ground all trees have a symbiosis with fungi, enabling the fungi to gain glucose from the tree in exchange for water and mineral ions but each fungi doesn’t just tap up one tree for this. Instead the hyphae of the fungi link different trees, often of the same species but sometime of different species, all together into a vast network. If you have seen Avatar this might ring a bell. This connectedness allows trees to share resources with each other in times of need; for example when one member of the forest is sick or when certain species are in leaf but others are yet to be.
But why would trees want to do this? Surely if your neighbour is sick then you will be able to grow above them and gain access to the precious sunlight that they are shading you from? Well yes and no, plants do compete but trees all do better in an intact forest: low wind speeds and cool temperatures lead to reduced evaporation and more water for all, as well as reduced risk of being blown over. But they don’t just give each other glucose, they can also signal to each other about potential risk, such as insect attack or disease. The key players in these networks are the old trees, those mighty majestic mothers of the forest who are probably 500 years old, and this has implications for forest management. There is a great TED talk about this by the researcher who discovered these networks Prof Suzanne Simrad called “How trees talk to each other.”
I recommend reading, listening to or watching any/all of these links. Truly fascinating.
Hidden Life of Trees (Book) https://www.amazon.co.uk/Hidden-Life-Trees-Communicate-Discoveries-Secret/dp/1771642483
Prof Suzanne Simrad TED Talk
RadioLab “From tree to shining trees” http://www.radiolab.org/story/from-tree-to-shining-tree/