A proscribed burn at Pocosin Lakes National Wildlife Refuge. Credit: Curt Richardson, Duke University High-intensity fires can destroy peat bogs and cause them to emit huge amounts of their stored carbon into the atmosphere as greenhouse gases, but a new Duke University study finds low-severity fires spark the opposite outcome.
The smaller fires help protect the stored carbon and enhance the peatlands’ long-term storage of it.
The flash heating of moist peat during less severe surface fires chemically alters the exterior of clumped soil particles and "essentially creates a crust that makes it difficult for microbes to reach the organic matter inside," said Neal Flanagan, visiting assistant professor at the Duke Wetland Center and Duke’s Nicholas School of the Environment.
This reaction—which Flanagan calls "the crème brulee effect"—shields the fire -affected peat from decay. Over time, this protective barrier helps slow the rate at which a peatland’s stored carbon is released back into the environment as climate-warming carbon dioxide and methane, even during periods of extreme drought.
By documenting this effect on peatland soils from Minnesota to Peru, "this study demonstrates the vital and nuanced, but still largely overlooked, role fire plays in preserving peat across a wide latitudinal gradient, from the hemi-boreal […]