After the leaves come down, I start to notice all sorts of new things: moss-covered boulders, varying topography, the sparkle of a creek. “Stick season,” say the Eeyores among us. “See-through season,” counter the optimists.
While the rough-barked trunks stand stoically separate, delicate twigs trace a burly lace onto gray skies. Although in silhouette they seem to intertwine, in reality they strive to lift their leaves (when they have them) away from the others to claim their own personal space. Occasionally, two trunks or two branches will miscalculate and intersect to squeak in the wind, or groan as scar tissue melds them together until in death do they part. The real connections, though, happen beneath the duff—almost beneath our notice.
Down there, hidden in the soil, lies the Wood Wide Web. No, that’s not a joke. Dr. Suzanne Simard, a forest ecologist from the University of British Columbia, coined the term to describe the relationships she discovered.
Other scientists have backed up her findings. According to German forester Peter Wohlleben, in his book The Hidden Life of Trees, “most individual trees of the same species growing in the same stand are connected to each other through their root systems.” They accomplish this by grafting. Just like orchardists can coax a new twig to grow on the branch of another apple tree, when two roots of the same species meet underground, they can grow together. The resulting network allows sugars, water, minerals, and chemical signals to travel from tree to tree, and provides stability in windstorms.
What Dr. Simard found even more intriguing, though, was that trees of different species can share resources, too, even though their roots don’t fuse together.
If you follow the roots of almost any plant out to their very tips, you’ll find fungal mycelia. Some fungi just sheath the roots; others actually tap into the root cells. Each plant has its preferred method of connection, and certain species of fungi that it consents to form relationships with. Fungal mycelia extend the plants’ reach into the surrounding soil. This mycorrhizal (myco=fungus; riza=root) network is robust and thickly woven. So thickly, in fact, that scientists say you could find seven miles of fungal hyphae in a pinch of dirt, and hundreds of miles under a single footstep.
Using this network, trees and mycorrhizal fungi live in an incredible symbiotic relationship. Trees feed the fungi with sugars produced during photosynthesis, and may share up to 80 percent of their total production. In return, fungal hyphae significantly increase the absorbing area of roots, which protects trees against drought. Fungi actively break down tightly bound soil nutrients like phosphorous and iron and make them available to plants. This intricate web captures and holds nutrients before they can be lost from the system.
What’s more, mycorrhizal fungi can facilitate nutrient sharing between trees and plants of different species, and take an active part in maintaining a healthy forest. Fungi depend on the presence of a mature, stable forest with its humid microclimate and flow of nutrients. Tree diversity is essential, since monocultures are vulnerable to disease and disturbance. Fungi ensure their own survival when they cultivate the long-term stability of the environment they enjoy. Of course, it’s not a zero-sum game. Many creatures, including us, contribute to and benefit from this synergy. All flourishing is mutual.
Just this little bit of knowledge will help you this fall, to “see through” the superficially independent members of the Wood Wide Web.
By Emily Stone