Controlled forest burning can help to offset emissions

Controlled burning of natural environments could help to offset carbon emissions, according to researchers at the University of Cambridge. 

The study, published in the journal Nature Geoscience, highlights how controlled burning can actually help to mitigate the severity of future wildfires. 

Fire burns plant matter and organic layers within the soil and in severe wildfires this leads to erosion and leaching of carbon. 

However, according to the study, fires can also cause other transformations within soils that can offset these immediate carbon losses and may stabilise ecosystem carbon. 

Fire stabilises carbon within the soil in several ways. It creates charcoal, which is very resistant to decomposition, and forms ‘aggregates’ – physical clumps of soil that can protect carbon-rich organic matter at the centre. Fire can also increase the amount of carbon bound tightly to minerals in the soil.

Without fire, soil carbon is recycled – organic matter from plants is consumed by microbes and released as carbon dioxide or methane. But infrequent, cooler fires can increase the retention of soil carbon through the formation of charcoal and soil aggregates that protect from decomposition.

The scientists say that ecosystems can also be managed to increase the amount of carbon stored in their soils. Much of the carbon in grasslands is stored below-ground, in the roots of the plants. Controlled burning, which helps encourage grass growth, can increase root biomass and therefore increase the amount of carbon stored.

‘In considering how ecosystems should be managed to capture and store carbon from the atmosphere, fire is often seen as a bad thing. We hope this new study will show that when managed properly, fire can also be good – both for maintaining biodiversity and for carbon storage,’ said Dr. Adam Pellegrini in the University of Cambridge’s Department of Plant Sciences.