Restoring wildfire to the Sierra Nevada: Impacts on water resources and drought response: Webinar

About the Webinar

 Fire suppression in the Sierra Nevadas has led to highly dense and homogeneous forests. Such landscapes use large amounts of water, and reduce the amount of rain and snow that reaches the ground. This could mean that fire suppression leads to a decrease in water available for streamflow or sustaining plants through long summers. Forest management strategies in which lightning-caused fires are allowed to burn naturally (within specified safety parameters) have potential to reverse the effects of fire suppression. Following a century of fire suppression, The Illilouette Creek Basin in Yosemite National Park has experienced 40 years of wildfires, reducing forest cover and increasing meadow and shrubland areas. We have collected evidence from field measurements, remote sensing, modeling, and streamflow data which suggests that restoring the fire regime has increased landscape and hydrologic heterogeneity, and likely improves resilience to disturbances such as drought and disease. Soil moisture observations during the drought years of 2013-2016 suggest that transitions from dense forest to shrublands or meadows following fire can increase summer water storage. Recent snow depth measurements in Illilouette Basin showed deeper spring snowpacks in burned areas compared to dense forests, which has big implications given the importance of snow to the water resources of California. Results from a distributed ecohydrological model demonstrate both localized and basin-scale hydrological effects of the observed fire-caused land cover changes. This watershed provides a unique view of relatively long-term effects of restoring a landscape’s frequent fire regime on vegetation change, changes in water stores, and drought resistance. Understanding these effects is increasingly important as management of wildfires for resource benefit becomes more widely accepted, and as the likelihood of drought and wildfire increase.

About the Presenter

Gabrielle Boisramé is a postdoc in the Stephens lab at the University of California, Berkeley. Her current research focuses on the interactions between wildfire, land cover, and water in the Sierra Nevadas. Since 2013 she has been using a combination of fieldwork, remote sensing, and hydrological modeling to explore how managing natural wildfire in landscapes can improve water resources and forest health. This work is focused in Yosemite and Kings Canyon National Parks. Dr. Boisramé received her PhD in environmental engineering from UC Berkeley and earned a B.A. in applied mathematics at Whitman College.