From Raging Wildfires to Habitat Restoration | Soil Health

Washington (GGM) Analysis | February 14, 2021 by Catherine Zacuto, M. Ed.

Wildfires are unpredictable, destructive, and, in recent times, more common. Among their many victims is the soil. Soil forms the foundation of our food chain, and so is of primary importance. Cristina Santin and Stefan H. Doerr conjure up a graphic image for us: Soil is the “living, breathing skin of the Earth.” It’s an image to keep in mind when considering how the land recovers from a fire.

What’s the heart of the matter? According to Santin and Doerr, fires affect soil in different ways, depending primarily on the temperature of the fire. At lower temperatures, fire reduces the microbial biomass that releases carbon dioxide and plant nutrients into the soil. It destroys seed banks and fine roots. At higher temperatures, the chemicals in the soil, like the pH, change. This impacts the stability of the soil and its ability to absorb water. All of these lead to the increased likelihood of soil erosion.

As often happens, a storm comes on the heels of a fire, dramatically increasing the danger of mudslides and debris flows. Even months after the fire, burn-scarred areas are threatened. Big Sur, experienced this recently as a portion of scenic Highway 1 near a burn-scar was washed out after a torrential rainstorm. While there are some benefits to natural soil erosion (adding essential nutrients to streams and rivers) with the advent of climate change and its extreme weather events, soil erosion has become a problem. Crops suffer as the nutrient-rich topsoil gets washed away, leaving exposed bare mineral soil that water cannot penetrate. This means less carbon for plants and less carbon stored. Fires also create the opportunity for aggressive invasive species to take root, harming native plants and causing soil damage.

How does this impact you? This issue affects our farmers more than any other population, and thus our food supply. The fields that grow our food are essential to our survival. Additionally, millions of tons of stored soil carbon are released during a wildfire. We simultaneously lose billions of trees that store carbon, creating a devastating long term effect. The path to restoring both the soil and the trees begins with soil health recovery. We need to take immediate action to prevent excessive soil erosion resulting from raging wildfires and devastating storms. Many universities and governmental agencies have joined in the effort, conducting research, reestablishing habitats, and keeping the public informed. But restoring the soil takes time, maybe even years. Throughout history, maintaining our food supply has been paramount. In modern times, we must also work to protect our resources. Restoring natural habitats strengthens the soil, allowing it to absorb and store carbon, a critical step toward meeting the goals of the Paris Climate Agreement.

What can you do to help? If you’ve been affected by fires and soil erosion, there are a multitude of resources available to help you recover and restore your environment, a few are listed below. Fortunately, revegetation may occur naturally after the fire. However, it is important to protect the soil as quickly as possible after a wildfire. The Forest Service has a few tips:

Mulch to establish ground cover to reduce the risk of soil erosion.
Build back the soil structure by reseeding native grasses to hold the soil in place and add nutrients and carbon back into the soil.
Create barriers with straw wattles, sandbags, silt fences, or straw bale check dams to prevent further erosion.
Introduce red wigglers, our eco-system engineers, to help expedite the timeline for soil recovery.
Avoid introducing non-native species which damage the soil and harm native plants.

Continued vigilance is required to prevent aggressive invasive species from taking over after a fire. According to the National Forest Foundation, they will continue to be a threat until native plants, trees, and shrubs are established.
Next Steps

Take preventative steps to protect your soil from eroding.
Add groundcover to secure and improve the soil.
Plant diverse native species of plants, trees, and shrubs.
Work with local organizations to add native trees, plants and shrubs to public spaces.
Pay attention to changes being made in your area, and make your voice heard.