EARTH SYSTEM SCIENCE
SEMINAR SERIES
 

October 30, 2025
12:00 - 1:00 PM
Y2E2, Room 299 
 

Scott Stephens, Ph.D.

Professor of Fire Science and Forest Policy
ESPM Department, UC Berkeley

“Forest Fires in California’s New Climate Reality: Challenges and Opportunities” 

Abstract
Fire suppression and past logging have changed frequent-fire-adapted forests making them much more vulnerable to wildfire and drought, climate change is making this problem even worse. Managed wildfire in Yosemite over the last 50-years has produced forests resilient to fire and climate change but more recent efforts have produced variable results. An extensive network of field plots across three short-interval successive fires in the northern Sierra Nevada evaluated the influence of forest structure, topography, and weather on fire severity in a third successive fire. Low- to moderate-severity fire has the ability to restore ecosystem processes but our results suggest that it can also create fuel conditions that drive higher fire severity in successive fires. Vegetation and fuel conditions existing prior to the initial first-entry fire can largely influence post-reburn outcomes, manipulating these forests with fuels treatments before wildfire could improve outcomes. Results from a 20-year fuels/restoration study in the northern Sierra Nevada found that all three active treatments (prescribed fire only, mechanical only, mechanical followed by fire) produced forest conditions that were much more resistant to wildfire than the untreated control. The only treatment that produced intertree competition somewhat similar to historical conditions was Mech + Fire, indicating these stands should be more resilient to forest stressors. Although California has focused on this issue in the past decades more completed projects are needed to conserve California’s forest into the future. Policies such as those found in Australia could enhance outcomes by getting more treatments implemented versus a US focus on planning.

Biography
Scott Stephens is interested in the interactions of wildland fire and ecosystems. This includes how prehistoric fires once interacted with ecosystems, how current wildland fires are affecting ecosystems, and how future fires and management will influence people and ecosystems. He is also interested in wildland fire and forest policy and how it can be improved to meet the challenges of the coming decades, both nationally and internationally. Working with Indigenous partners to learn how to steward ecosystems into the future with climate change is a key area of research.

Stephens has given testimony on fire and forest policy at the US House of Representatives, the White House, California Assembly and Senate, California Governor’s office, and severed on the 2024 US Wildfire Commission. He is on the Board of Directors of the Climate Wildfire Institute and is one of the leaders of The Stewardship Project which is a partnership of Indigenous people and western science to improve federal fire policy. He was selected in the  Top 1% of Researchers Worldwide in 2024 (https://clarivate.com/highly-cited-researchers/)