Central OC Times

The severity of wildfires in California has increased significantly over the past few decades due to climate change, according to a study published in Environmental Research Letters by researchers from the University of California, Irvine and the University of Utah. The study highlights that this increase in wildfire intensity has led to accelerated tree losses.

Jon Wang, a professor at the University of Utah and former postdoctoral researcher at UC Irvine, stated, "As California’s climate has become warmer and drier, the severity of the average wildfire increased by 30 percent between the 1980s and 2010s." This escalation means that for every acre burned, damage to tree canopies is greater than it was several decades ago.

James Randerson, co-author of the study and professor at UC Irvine's Department of Earth System Science, explained that more fires are now reaching tree crowns. "When fire moves over a forest’s floor, often the tree canopy will survive and, in some situations, thrive from fire effects on nutrient cycling," he said. "The new research suggests more fire is jumping into the tree crowns, causing more damage and tree mortality."

The researchers noted that wildfires have expanded into new areas with denser forests which were previously protected by cooler summers and higher moisture levels. These regions include northern mountain and coastal areas. Wang commented on this expansion: "There’s a pretty shocking map of just how much these fires have expanded into northern California forests."

The team aimed to determine how much rising tree cover loss is due to increased area burned versus increasing wildfire severity or fires moving into denser forests. Prior research led by Wang indicated a 7% decrease in total tree cover since 1985 due to wildfires and drought-induced die-off.

"We found that on a relative scale tree cover losses were rising faster than the fire-burned areas were," said Wang. This implies that not only are fires getting larger but they are also burning more intensely.

Using satellite imagery from the U.S. government's Landsat Program starting in 1985, researchers quantified fire-driven tree cover loss over recent decades. Randerson emphasized their unique approach: "While past studies have measured fire severity, our study is unique in allowing for a quantitative breakdown of the importance of burned area, severity and forest exposure for the loss of California’s forests."

Wang noted potential changes in forest composition: "Severely burned forests could be replaced by something more adapted to the hot, dry climates of Southern California."

Funding for this research came from various sources including California's Strategic Growth Council Climate Change Research Program and NASA's programs.

UC Irvine continues its efforts through its Brilliant Future campaign launched publicly on October 4th, 2019 aiming for significant philanthropic investment towards university growth across various sectors.

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