High-severity wildfire is increasing in Sierra Nevada and Southern Cascade forests and has been burning at unprecedented rates compared to the years before Euro-American settlement, according to a study from the Safford Lab at the University of California, Davis, and its collaborators. Those rates have especially shot up over the past decade. 

Just over 9,900 wildfires burned about 4.3 million acres in 2020. That’s more than twice the previous record of acres burned in California. Yet it is about average compared to burn rates likely experienced before Euro-American settlement, according to a study from the University of California, Davis, that summarizes the 2020 fire season and examines its drivers.

Smoke billows over the forest like a slow-moving fog. Dried oak leaves singe, crackle and curl into ash. Neighbors, scientists and agency staffers rake the embers, directing the flames with calm, careful control. Ted Odell’s grandson runs along his namesake trail, Henry’s Hill, to adjust a hose. 

This is Odell’s property in Placer County, where five of his 11 acres are being burned by prescribed fire with assistance from Placer County Resource Conservation District, UC Davis researchers and others. 

Aerosols carried in wildfire smoke plumes that are hundreds of hours old can still affect climate, according to a study out of the University of California, Davis. 

The research, published in the journal Environmental Science and Technology, suggests that wildfire emissions even 10 days old can affect the properties of aerosols — suspended liquid or particles that are key to cloud formation. 

What does a “resilient” forest look like in California’s Sierra Nevada? A lot fewer trees than we’re used to, according to a study of frequent-fire forests from the University of California, Davis.

More than a century ago, Sierra Nevada forests faced almost no competition from neighboring trees for resources. The tree densities of the late 1900s would astonish most Californians today. Because of fire suppression, trees in current forests live alongside six to seven times as many trees as their ancestors did — competing for less water amid drier and hotter conditions. 

UC Davis is part of a team of western land grant universities sharing a $7.5 million grant from the U.S. Department of Agriculture to study the effect of wildfire smoke on grapes and wine.

Oregon State University is leading the 4-year project to better understand how wildfire smoke compromises grapes, which poses a threat to the $20 billion wine industry in the United States.

When hikers returned to UC Davis Stebbins Cold Canyon Reserve in 2016, a year after a wildfire swept through its expanse of oak trees and chaparral in Northern California, half of them expected to see a devastated landscape. But pre- and post-hike surveys conducted by the University of California, Davis, reveal that roughly a third returned energized, awed and excited about the changes they saw.