Publication Date
5-8-2026
Document Type
Article
Publication Title
Fire Ecology
Volume
22
Issue
1
DOI
10.1186/s42408-026-00486-4
Abstract
Background: Chaparral, including maritime chaparral, burns at high severity, but also has unique fire intensities within sites due to weather, topography, and fuels. These differences cause unique fire effects, including fuel consumption and floral biodiversity. A highly instrumented prescribed headfire within a steep canyon (California Canyon Fire Experiment, Salinas, CA) provided an opportunity to investigate the relationship between thermal image measurements, taken from both helicopter and ground stations, and vegetation burn severity. We used remote sensing to describe thermal exposure as a proxy for fire intensity, including maximum temperature and duration at high temperatures, across a range of fire intensities. Then, we compared methods of measuring post-fire remaining twig diameter for two species: Adenostoma fasciculatum (chamise) and Salvia mellifera (black sage). Results: Our results show that some post-fire twig diameter sampling methods do not relate well to thermal imagery-based thermal exposure. Duration of heating is a better indicator of fire effects than maximum temperature. For duration of heating, twig diameter is influenced most by how long the shrubs burn above lower temperatures rather than time at higher temperatures. While black sage and chamise have significantly distinct fire effects in terms of remaining twig diameter, the magnitude of difference was small and likely not ecologically important. Lastly, because the relationship between severity and twig diameter may diminish as twig tips weather, the timing of measurements is an important consideration for post-fire assessments. Conclusions: More wildfires and prescribed fires are occurring in chaparral, and both researchers and managers want to assess their fire effects. For prescribed fires, managers and researchers concerned about the desired heterogeneity of fire effects may benefit from using twig measurements as a fire severity proxy. More understanding of chaparral fire effects is needed to grasp the implications on biodiversity. Future refinement of estimating fire severity may help researchers and managers in this goal.
Funding Number
2230778
Funding Sponsor
San José State University
Keywords
California Canyon Fire Experiment, Fire effects, Mediterranean, Prescribed fire, Shrub, Shrubland, Wildfire
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
Department
Urban and Regional Planning; Meteorology and Climate Science; Biological Sciences
Recommended Citation
Jannike E. Allen, David Benterou, Henri Brillon, Killian T. Cook, Andrew Klofas, Xiangyu Ren, Craig Clements, Ashley R. Grupenhoff, Mario Miguel Valero, Bo Yang, and Katherine M. Wilkin. "Reexamining the Relationship Between Post-Fire Twig Diameter and Fire Intensity in California’s Chaparral to Better Assess Fire Severity" Fire Ecology (2026). https://doi.org/10.1186/s42408-026-00486-4
