In our earlier posts about “The Power of Trees,” we have discussed how trees hear, feel, and react. This time we will tackle about how trees communicate with each other thru a system. If you were asked this question, do trees communicate with each other? What would be your answer? For someone who hasn’t been reading about trees, their answer would be no. Surprisingly, the answer is yes.
How Trees Communicate
Trees might appear tall, strong, and silent, but they communicate with each other. According to Dr. Suzanne Simard, a popular forest ecologist from the University of British Columbia, a type of fungi is formed underground which serves as a communication network between trees in North American forests. Mother trees in the forest are hubs in this mycorrhizal fungal network, it plays an important role in supporting other trees around it, particularly their offspring.
According to Simard, just like a mother, the trees will treat its offspring in certain ways. The trees will set aside their competitive behavior to make room for their newest kin and send signals via mycorrhizal networks. The biggest, oldest trees are connected more to other trees than the smaller trees since they have more root systems. Thus, when a new tree establishes on the forest floor, if it is only a few feet away from the mother trees it will link into the same network and accesses the biggest resource network.
The fungal networks don’t work only between related trees, but likewise among trees of different species in the similar community. In a study done by Simard and published in the 1997 issue of Nature, she used radioisotopes to trace nitrogen, water, and carbon moving between a paper birch tree and a Douglas fir, which are both abundant in the inland forests of British Columbia. When Simard shaded one tree, the carbon-based sugars would be transported to the other tree. Thus, instead of competing for resources, they are sharing it using the fungal networks. An estimated 250 to 300 trees are connected to each other via the fungal network in a single forest stand.
Another proof trees use fungal networks to communicate with other trees is when there is an incoming threat from pests. When trees are attacked, their defense mechanism increases to protect them against their invaders. They do this by boosting their defense genes to produce defense enzymes. To warn their neighbors, the mother trees sends chemical signals to their roots via the mycorrhizal networks. When other trees received the signals, they upregulate their defense genes as well.
According to Simard, the defense signals travel among trees in as short as 6 hours. She also added, when fungal networks are undamaged they allow a different variety of trees, each with their own weaknesses and strengths, to stay alive in the forest.