Nature’s Friendships

Author: Ellie Wang

Editor: Liane Xu

Artist: Nicole Tseng

What do you think of when you picture a forest? Conventionally, it would be a collection of silent and isolated trees, grouped only because of their physical closeness. However, new research reveals that forests are communities, connected through a network of symbiotic relationships with fungi. Mycorrhizae, a type of symbiotic relationship that exists between plants and fungi, are the key to a thriving forest.

If we travel back in time, we would witness the migration of plants and fungi from the ocean onto land. These organisms each had one distinct kind of struggle. Plants couldn’t readily absorb the required nutrients and minerals, and fungi couldn’t harness the sun’s energy to create carbohydrates for energy to sustain life processes. To put it simply, they needed each other. Plants perform photosynthesis to provide energy for both of them, and fungi absorb nutrients and minerals from the soil in the same considerate manner. Thus, about 520 million years later, old-growth forests, filled with trees of all ages, still stand with the help of mycorrhizae.

Mycorrhizae networks exist underground, with fungi connected to the roots of trees. This allows the flow of nutrients and carbohydrates between fellow trees and between tree and fungus. Resources usually flow from the oldest trees to the youngest. Sometimes, dying trees even give a significant amount of their carbon to others connected to the network, providing for them even in their final moments. Research done by Suzanne Simard, a professor of forest ecology at the University of British Columbia, demonstrates that old-growth forests are successful due to mycorrhizae. In contrast, commercial logging fields, cleared of any old trees or mycorrhizae, are full of saplings vulnerable to disease and climatic stress. It’s no wonder that about 90% of all vascular land plants are connected by mycorrhizae. Contrary to the principles of Darwinism, altruism is the secret to the survival of trees, not ruthless competition.

Trees and fungi aren’t the only ones to live with these lifelines. Humans are teeming with microbes in our guts, assisting us indigestion and modifying our immune systems. In nearly every cell, there are energy-producing mitochondria which were once free-roaming bacteria, now living within us. Frankly, humanity wouldn’t be where it is right now without these precious symbiotic relationships. In this case, nature can teach us a valuable lesson of altruism and compassion. How much do we hamper progress by not reaching out a helping hand?

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