Sunlight has returned to the Yukon, and each day more and, as the ground thaws, a universe beneath our feet is waking up. Sure, we look forward to spring, to the pastel tones and the flowers, but in reality, the season is a mucky one. As the snow melts, last year’s half-forgotten projects emerge from the snow and thawing “evidence” of dog ownership in the yard. The smell of old decaying leaves and mud permeates the air. But don’t lament this brown and smelly period; rather, rejoice that it’s within the mud and the rotting leaves that magic is underway.
Our tiny neighbours in the soil (including bacteria, fungi, protozoa and worms) are getting to work breaking down the leaves, the cast-off fruit peels and, yes, the dog’s collection in the yard. These overlooked creatures break down large pieces of dead material into smaller and smaller pieces that are sifted into the soil. From there the feast really begins, with an entire universe of species all playing their role, breaking down one thing or another. Looking at the volume of life teaming in the soil makes our above-ground life look rather basic. In fact, one teaspoon of healthy soil can contain more creatures than there are humans on Earth, and can be composed of up to 50,000 unique species.
It is this cosmos of creatures that not only decomposes remnants of the year before, but that also plays a key role in our carbon emissions. For healthy old-growth soils, made cool by the shade of trees, it’s our soil-borne friends that directly reduce carbon emissions to the atmosphere by trapping carbon in new soil. However, if we clear the trees and let the sun warm the soil, that process shifts from carbon storage, to the opposite—releasing carbon dioxide to the atmosphere, rather than building up soil. But old-growth soils do so much more, and every day we get glimpses of their magic.
That old-growth soil is knit together into a tapestry of fungal threads (hyphae) that is more remarkable than can be believed. Those threads, growing through the soil, break down nitrogen, potassium and phosphorus that enable plant communities above them to thrive. Some also use powerful acids to break down rocks, to release key minerals like zinc and copper. Bacteria famously enable plants to capture nitrogen from the air by building shared tissues in the roots of some plants.
While many of us know that the fungi are a key part in decomposition, some fungi are hunters in the soil, using their growing threads to stalk and hunt prey. The fungal threads snake through the soil and seek out roundworms and invertebrates to feast on. Some fungi find their prey and envelop them, but more surprisingly, other species attack their targets with poisonous harpoons concealed in their cells. The oyster mushrooms you see at the grocery store are one of those vicious hunters in the soil who survive by attacking and paralyzing tiny worms in the soil.
Without a doubt the most fascinating part of our underfoot world is what scientists have called the Wood Wide Web. The Wood Wide Web describes complex interconnections between plants, fungi and other species that serve as both a communications network, as well as a pipeline of shared nutrients. Through this fungal network, trees share information via chemical signals that communicate about insect attacks, disease outbreaks and other threats to the forest. These messages are relayed between the tips of plant roots and the threads of fungi, across vast distances. This relationship is not free for the trees; the fungi charge a “fee” to be a “post office and takeout joint.” To pay for the service, trees share up to one-third of their sugar production with their fungal partners. Like the capturing of carbon in soil, this network requires old-growth soil that is free from disturbance. It’s this co-operation among species that challenges notions of what competition in nature looks like and how ecology has many models of success. Today, more and more discoveries are made that expand the range of information and nutrients shared through the soil.
So, this year, rather than just celebrating the return of the leaves, think about the wonderous world beneath each of our steps. And when you see the first mushrooms of the year starting to pop up, remember, they are charismatic spokespersons for a community we are only beginning to glimpse. For more information, check out books by Suzanne Simard, Peter Wohlleben, and Merlin Sheldrake.
