A new study published in Environmental Research Letters reveals that the severity of the state’s wildfires has rapidly increased over the last several decades, contributing to greater forest loss than would have been expected from past increases in burned areas.
“Fire severity increased by 30% between the 1980s and 2010s,” said Jon Wang, an assistant professor at the University of Utah School of Biological Sciences. This means that for every acre of forest scorched by fire, the damages to mature trees are considerably higher than what occurred in the average fire several decades ago.
“When fire moves through an area on the forest floor, often mature trees survive and, in some situations, they may thrive from fire effects on nutrient cycling,” said study co-author James Randerson, professor in the UC Irvine Department of Earth System Science. “The new research suggests more fire is jumping into the tree crowns, causing more damage and tree mortality.”
“Forest exposure has increased 41% over the past four decades, suggesting denser forests are now more vulnerable to wildfire,” said Wang.
“There’s a pretty shocking map of just how much these fires have expanded into northern California forests,” Wang said. “There’s just a lot more fire in these northern forests than there used to be. Climate change allows severe fires to affect forests that once tolerated milder fires.”