Ladder Fuels – Not Total Biomass
Wildfires are becoming more extreme, and understanding what drives their severity is critical for better forest management. A new study using NASA’s GEDI spaceborne lidar has uncovered a surprising result: ladder fuels—not total biomass—are the best predictor of wildfire severity. Even in extreme conditions like steep slopes and high winds, the structure of fuels beneath the canopy dictated fire intensity. These findings challenge traditional wildfire models and highlight the power of lidar in understanding fire behavior at scale.
GEDI: A Game-Changer for Wildfire Research
The Global Ecosystem Dynamics Investigation (GEDI) is a spaceborne lidar system installed on the International Space Station (ISS), designed to measure the 3D structure of forests. Unlike traditional satellite imagery, which primarily captures the forest canopy, GEDI penetrates through the layers of vegetation, providing an unprecedented view of fuel structure from the ground up. By delivering high-resolution vertical profiles of forests across the globe, GEDI enables scientists to quantify biomass, canopy height, and fuel continuity—essential data for modeling wildfire behavior. Its ability to collect consistent, large-scale lidar data makes it an invaluable tool for wildfire risk assessment.
A New Paradigm For Fire Management
This study analyzed 42 large wildfires in California from 2019–2021 and found that ladder fuels—vegetation between 0–10 meters—were the strongest predictor of wildfire severity. Traditional metrics like canopy biomass and height were less reliable, especially under extreme conditions such as high winds (greater than 9.3 meters per second) and steep slopes (greater than 20 degrees). The results suggest that fire management strategies should focus more on reducing ladder fuels rather than thinning entire canopies. GEDI-derived metrics outperformed optical imagery and airborne lidar in predicting fire behavior, reinforcing the importance of 3D fuel structure data.
With wildfire severity increasing due to climate change, GEDI’s insights can revolutionize how we assess and manage fire risks. Forest treatments targeting ladder fuels, such as understory thinning and prescribed burns, could be key to mitigating future megafires.
For a deeper dive, check out the full publication:
Ladder fuels rather than canopy volumes consistently predict wildfire severity.
For more examples of lidar being used in forestry, please visit Riegl’s Innovative Solutions for Forestry Applications.
