The Ents: they’re walking, talking trees, and they are a figment of Tolkien’s imagination, right? Not quite. Tree species around the world can cooperate via their fungal friends, and they are connected to each other through a complex web of ecological interrelationships that sounds like it has leaped off of the pages of a fantasy book.
Fungi and Trees: An Unseen Partnership
You might know that trees and fungi are connected. You walk through the forest and you notice that certain large fungi love to sprout up next to certain types of trees. The story below the soil is even more complex. Some trees like the Red Alder (Alnus rubra) have fungal symbionts such as Alpova diplophloeus, Paxillus inuolutus, Astraeus pteridis, and Scleroderma hypogaeum. These fungi allow certain trees and other plants to move nitrogen from the air into the soil: essentially, these trees fertilize the soil as they grow.
The Struggle to Survive in the Forest
However, the connections between fungi and trees run deeper than that. At the beginning of their lives, baby trees have a hard go of it. The environment is dark underneath the canopy of the bigger trees, and those large trees have the ability to hog the water and soil resources, starving the baby trees who struggle to survive. But somehow another generation of trees grows slowly upward. How can this be?
Baby Trees Survive With a Little Help From Their Parents
Baby trees survive and thrive through fungi, and with a little help from their parents. Although the larger trees could take up all of the forest’s resources, they don’t. Just as the branches of the forest canopy interconnect, the roots and fungi underneath the ground are connected as well. And underneath the ground, they’re carrying out a subtle negotiation of resources that allows smaller trees to survive.
Underground Networks of Fungi Help Grow New Trees
University of British Columbia forest ecologist Suzanne Simard discovered that the trees were using fungal networks to move water, carbon, and other resources to the smaller trees in the forest. These resources are essential to tree life and growth. The largest trees in the forest hold the most fungal networks, and they have the ability to distribute resources to the smaller trees. In a way, these trees are cooperating.
Humans live above the ground. Like the ecosystems beneath the surface of the oceans, the world underneath the soil is one that is foreign to most of us. It can be hard to believe that soil life is so complex, but it is, and it sustains the vast diversity of life above the soil. Although we tend to think of plants as competing for light, nutrients, and water, the reality is that plants are more cooperative than we might think, thanks to the assistance of their fungal associates.
Mycorrhizal Ecology. Marcel G. A. van der Jeijden and Ian R. Sanders, eds. Ecological Studies 157. Springer, 2002.
Northeastern Area State and Private Forestry. Red Alder. Accessed June, 2011.