Understanding Wildfire Severity

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Introduction to Today’s Video

Wildfire ‘severity’ describes the ecological effects of a fire. At a landscape-scale, severity is measured using satellite imagery. This process uses images of the vegetation from before and after the fire to create colored maps which show how much plant life is still alive after the fire.

In this episode, we dig deep into the severity patterns of some of Northern California’s largest forest fires in the past 20 years. Our objective is to use real-world examples of how specific fires burned to understand the variety of factors which influence how hot a wildfire burned in specific places. What can the patterns of hot vs cool burns teach us about how fire interacts with landscapes and fuels? How might we use fire to manage wildlands? How does previous management of the land influence its relative flammability?

For this broadcast, we used raw satellite data provided by Drs. Brandon Collins and Jacob Levine in their 2022 research paper ‘Higher incidence of high-severity fire in and near
industrially managed forests’. This research found that:

…Where fires occurred, the odds of high-severity fire on “private industrial” lands were 1.8 times greater than on “public” lands and 1.9 times greater than on “other” lands (that is, remaining lands classified as neither private industrial nor public). Moreover, high-severity fire incidence was greater in areas adjacent to private industrial land, indicating this trend extends across ownership boundaries. Overall, these results indicate that prevailing forest management practices on private industrial timberland may increase high-severity fire occurrence, underscoring the need for cross-boundary cooperation to protect ecological and social systems.

I wanted to take a look at their raw data, and do some visual checks on whether or not their findings held up on fires that I have had personal experience on, either mapping, doing fuels management planning, or that have come up in conversation with my mentors and friends over the years. This broadcast is an extended/freewheeling map tour of some of the larger NorCal fire assignments from my career.

Watch the Livestream, Here:

AI Summary of the Livestream

Zeke Lunder, a geographer from Chico, discussed fire severity in Northern California during a live stream on July 16, 2025. He highlighted the slow start to the fire season and focused on the Green Fire and Butler Fire, noting their current status and strategies for containment. Lunder explained the use of satellite imagery to map fire severity, emphasizing the impact of land management history on fire behavior. He analyzed data from fires between 1992 and 2018 provided by the authors of a paper that found private timberlands often burn with higher severity than public lands. Lunder also discussed the challenges of managing fires in areas with mixed public and private land ownership.

Introduction to the Lookout Live Stream

  • Zeke Lunder introduces the live stream, mentioning it is about wildfire, prescribed fire, and forestry in Northern California.
  • Zeke Lunder provides his background as a geographer working in Chico, focusing on water and wildfire issues.
  • The live stream is sponsored by QTAC Fire, FyreBxx, and WATERAX pumps.
  • Zeke Lunder mentions the slow start to the fire season in Northern California and the focus of the live stream on fire severity.

Overview of Current Fires in Northern California

  • Zeke Lunder discusses the Green Fire and the Butler Fire, noting their current status and the weather conditions affecting them.
  • The Green Fire is smoking daily and pushing lightly to the north, affecting the Modoc Plateau.
  • The Butler Fire is also active, with mapping showing the fire’s progress and the efforts to contain it.
  • Zeke Lunder explains the strategy of tying in the Sulanharas/Squaw Creek arm to control the fire.

Fire Severity Mapping and Satellite Imagery

  • Zeke Lunder explains the use of satellite imagery to map fire severity, highlighting the disruption in the forest canopy.
  • The satellite imagery is sensitive to chlorophyll, showing areas that have been burned more severely.
  • Zeke Lunder describes how plants absorb sunlight, affecting the reflection of different wavelengths of light.
  • Some of the high severity areas in the imagery often are areas that were brush before the fire, burning to black.

Factors Influencing Fire Severity

  • Zeke Lunder discusses the factors influencing fire severity, including fuel moisture, weather, topography, and previous land management.
  • The severity of the Green Fire is described as largely beneficial, with the fire burning slowly and not spreading rapidly.
  • Zeke Lunder mentions the Grand Canyon fire, which was being managed for resource benefit, but caused great damage when it blew up due high winds.
  • The importance of understanding potential fire severity for prescribed fire management is emphasized.

Historical Fire Severity and Land Management

  • Zeke Lunder reviews historical fires in the Klamath Mountains, including the Gap Fire and the Beaver Fire.
  • The impact of past fire severity on future fire behavior is discussed, with examples of areas that burned severely in previous fires.
  • The role of land management in shaping fire severity is highlighted, with examples of private and public land management.
  • Zeke Lunder discusses the challenges of managing fires in areas with mixed land ownership and the impact of past fire severity on future fire behavior.

Impact of Land Ownership on Fire Management

  • Zeke Lunder explains the concept of checkerboard land ownership and its impact on fire management.
  • The challenges of managing fires in areas with mixed public and private land ownership are discussed.
  • The importance of understanding the historical context of fire severity and land management is emphasized.
  • Zeke Lunder suggests consolidating public/private ownerships to improve fire management options in areas with mixed land ownership.

Case Study: Bagley Fire and Fire Severity

  • Zeke Lunder discusses the Bagley Fire that burned in 2012, highlighting the differences in fire severity between private and public lands.
  • The impact of past fire severity and land management on the current fire behavior is examined.
  • The challenges of managing fires in areas with dense plantations adjacent to unmanaged fuel loads are discussed.
  • Zeke Lunder emphasizes the importance of understanding the historical context of fire severity and land management for effective fire management.

Conclusion and Future Directions

  • Zeke Lunder concludes the live stream by thanking the sponsors and the scientists who provided the data on fire severity.