I ski around a bend on a wilderness trail and take a moment to enjoy the sun on my face and catch my breath. Native kinnikinnick, subalpine tree roots and a few dead flower stalks bask on a south-facing slope in a patch of warm soil — so warm the snow doesn’t stick. Last summer when I dug in my garden, there was life in the soil, but what about on this 25-degree day? I wonder what’s going on in this exposed soil, who is living here and what might be going on with the soil under the snow. Curious about anything to do with plants and bugs, I decide to dig a little deeper and “get the dirt” on winter soil. 

Scientific research reveals that soil is extremely dynamic. It is full of living organisms: insects, bacteria, fungi, protozoa and nematodes. In addition to organic matter, minerals and water, soil contains gases, primarily nitrogen, oxygen, and carbon dioxide. “In just a teaspoon of healthy soil, there are over 1 billion bacterial individuals and more than six miles of fungal mycelium,” according to the Denver Botanic Gardens. These soil inhabitants — critters, if you will — break down dying and dead plant and animal matter to create healthy nutrient-rich humus, otherwise known as great soil, to provide food for plants. 

Plants, in turn, provide shade to help soil retain moisture, supply nutrients and even impart sugars that act as antifreeze to the soil. This symbiosis, or the relationship between two organisms of different species, is like so many other relationships on the planet. Some examples are bees and flowers, whales and barnacles, paintbrush and penstemon and me and coffee. 

Living organisms in Colorado’s soil have evolved to endure our particular weather conditions: dry and cold. It’s easy to imagine their busy lives during spring, summer and fall when they happily munch and move and procreate in warm soil. But what happens to them in winter? 

Although some microbes may freeze and not survive, many merely slow down their munching and decomposing activities. They have also developed strategies such as living in pockets of water with a higher salt content, lowering their metabolic activities and traveling toward warmer soil temperatures. It’s sort of like me on a cold snowy day moving slowly toward a hot tub with a bag of chips. 

Soil responds to air temperature above ground and below ground due to heat emanating from the Earth’s core. In winter, soil layers deep in the ground are warmer than layers closer to the surface that are cooled by dipping winter air temperatures. Snow that stays on top of the ground without melting acts like an insulation blanket preventing the ground heat’s escape into the atmosphere and preventing cold air from getting in. This soil does not freeze as deeply as exposed soil and maintains a more welcoming environment for the living organisms. 

The exposed soil I saw on the south-facing slope is repeatedly freezing and thawing from lack of constant snow cover and is not as hospitable toward the surface for critters to survive. My guess is the greater abundance of these living organisms are actually under the snow-covered soil – and under our skis. An additional benefit of snow-covered soil is that it will melt more quickly in spring, which translates to more growing time for plants and more parties for the critters in the soil. 

Like our billions of neighbors under the snow, I hope you evolve some excellent strategies for surviving the cold temperatures ahead, create some lasting symbiotic relationships and enjoy our winter woods. Tread lightly.

“Get Wild” publishes weekly in the Summit Daily News. Sherie Sobke is an Eagle-Summit Wilderness Alliance hiker, volunteer ranger, backwoods skier, Sierra Club and Dark Sky member, owner of Alpine Earth Gardens and a supporter of Eagle Summit Wilderness Alliance, an all-volunteer nonprofit that helps the U.S. Forest Service protect and preserve the wilderness areas in Eagle and Summit counties. For more information, visit EagleSummitWilderness.org.