Trees and plants communicate to each other, and their community, above and below the ground. Above soil level, when trees are being attacked (stressed) they release volatile organic chemicals (VOC). These VOC are picked up by neighboring plants and forewarn them to defend themselves. These same chemicals can also attract help in the form of predators to feed on the attacking pests. Each chemical is a ‘word’ and these words are combined to make a specific sentence – this allows plants to chatter. A well known VOC is the aroma generated by freshly cut grass.
Below the ground, when trees are attacked they increase their defense against the invaders by revving up their defensive genes and increase their production of defense enzymes. They send these chemical signals down their roots to the mycorrhiza network, where neighboring trees detect these signals and trigger their own defense mechanisms. This can happen in as little as 6 hours.
Turns out, trees can’t live without their mycorrhiza. Under a simple footstep there are 300 miles of fungal highway. This connectivity is not just between same species but between all species and works like our internet. This forest connectivity is vast and is world wide. But why have this co operative between tree and fungus? It is quite simple; the fungus can’t photosynthesize but can pick up nutrients, especially Nitrogen and Phosphorus, and exchange these nutrients with the plants for their photosynthetic product of sugar.
The biggest users of the fungal network are the Hub trees. These are the mother trees which are nurturing the young in the understory. The hub trees send extra Carbon to the shaded understory young trees. In this way, the survival rate of the saplings increases 4X. It has been discovered that hub trees have kin identification capability where they can distinguish the difference between strange and kin trees. Mother trees have bigger mycorrhiza nodes and networks with related trees vs. strange trees. When a mother tree is injured or dying it will pour out excess Carbon into the fungal network but also defense signals.
So the next time you take a walk out into the woods – see the trees for the interwoven community that they are.