On the shores of Lake Tahoe at Emerald Bay State Park grows what some consider to be the most iconic old-growth forest in the Lake Tahoe Basin. Giant ponderosa pines — some of the last remaining in the area — share space with at least 13 other tree species.

New research from the University of California, Davis, is shedding light on when and where to plant tree seedlings to help restore forests after high-severity wildfires, and it has a lot to do with shrubs. 

In hotter, drier areas where natural regeneration is weaker, well-timed tree planting can boost recovery by up to 200%, but the outcome also depends on competition with shrubs, a paper in the journal Forest Ecology and Management concludes.

Long-term smoke exposure from massive wildfires lowers the energy reserves of orchard trees and can cut their nut production by half, researchers at the University of California, Davis, found. The smoke can affect trees for months after a megafire, depressing their bloom and the next season’s harvest. This finding reveals a new danger from wildfires that could affect plant health in both agricultural and natural environments.

Nature Plants published the study today (Oct. 2).

Not all forest fires have devastating effects. Low- and moderate-severity forest wildfires can reduce the intensity of future conflagrations for as long as 20 years in certain climates, according to new research by the University of California, Davis. 

Where there’s smoke, there’s not necessarily fire.

Wildfire smoke, sometimes drifting from hundreds of miles away, touched nearly every lake in North America for at least one day per year from 2019 to 2021, according to a study from the University of California, Davis. 

As much as 70% of California was covered by wildfire smoke during parts of 2020 and 2021, according to a study from the University of California, Davis. The study, published today in the journal Communications: Earth & Environment, combined lake-based sensors with satellite imagery to find that maximum smoke cover has increased by about 116,000 square miles since 2006.

Springtime brings native wildflowers to bloom in the Santa Monica Mountains, northwest of Los Angeles. These beauties provide food for insects, maintain healthy soil and filter water seeping into the ground — in addition to offering breathtaking displays of color. 

They’re also good at surviving after wildfire, having adapted to it through millennia. But new research shows wildflowers that usually would burst back after a blaze and a good rain are losing out to the long-standing, double threat of city smog and nonnative weeds.

Prescribed fire, which mimics natural fire regimes, can help improve forest health and reduce the likelihood of catastrophic wildfire. But this management tool is underused in the fire-prone U.S. West and Baja California, Mexico, due to several barriers. 

A paper from the University of California, Davis, pinpoints those obstacles and suggests four key strategies that policymakers and land managers can take to get more “good fire” on the ground in North America’s fire-adapted ecosystems. The paper also provides examples of how people are surmounting some of these obstacles.

As California works to meet climate and air quality goals, a key to the transition will come from biomass, which is renewable organic material from plants and animals.

Satellite data from across California’s landscapes reveal an increase in nitrogen dioxide levels in remote forest areas, and wildfire and soil emissions are likely the reasons why, according to a paper from University of California, Davis, published today in the journal Environmental Research Letters.