Wildfires are devastating to the soil

After another record year for California wildfire, concern is now turning to the soil impacted by firestorms, reported Sarah Klearman in the Napa Valley Register.

High-temperature flames can incinerate vegetation and destroy plant root systems, said Toby O'Geen, UC Cooperative Extension soil specialist at UC Davis. The loss of vegetation destabilizes the landscape, making it vulnerable to serious erosion or flooding.

"The most important way to battle erosion is to have surface cover - living vegetation anchoring your soil," O'Geen said. "We have none of that. If you have soil with existing susceptibility (to erosion) and now nothing to hold it in place, it's a new disaster."

Particularly catastrophic fire can make the soil surface water repellent, which allows water to pond up and release higher concentrations of run-off water even when rainfall is low.

"That creates more massive erosive events - it gives rise to accelerated erosion, and in some extreme instances, mudslides," O'Geen said.

An area near Shaver Lake where the 2020 Creek Fire burned most of the living vegetation and old tree stumps. (Photo: Jeannette Warnert)

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