PARENT SESSION
Contributed Oral Session 7: Disturbance Ecology: Fire; Litter; Animal response
Monday, August 8, 8:00 AM - 11:30 AM, Meeting Room 518 A, Level 5, Palais des congrès de Montréal
Fire rising in the forest: Ladder fuel hazard assessment using a mixed qualitative and quantitative approach.
Menning, Kurt *,1, Stephens, Scott1, 1 Department of Environmental Science, Policy and Management, Berkeley, CA, USA
ABSTRACT- The measurement of ladder fuels - vegetative matter that can convey flames from the forest floor up into the canopy - is important for understanding the severity of a fire's ecological effects in a forest. Unfortunately, ladder fuels are extremely difficult to measure due to their three dimensional arrangement. Previous efforts typically have been based on either expert opinion (quantitative) or intensive measurements (qualitative). Both approaches have severe limitations: expert opinion assessments vary and may not be repeatable; physical measurements can be laborious, expensive and spatially limited. We devised a mixed quantitative-expert opinion system for assessing ladder fuels. The Ladder Fuel Hazard Assessment (LaFHA) approach requires a trained technician to rapidly categorize low, mid and high aerial fuels using a flowchart. At the same time, the continuity of the fuel ladder is assessed both for minimum height to crown and maximum gap in the most continuous fuel ladder. The process is repeated for each of the four quadrants of a plot. The flowchart leads the evaluator to assign a LaFHA category with gap and canopy data. Later, during data processing, data on slope and vegetation type can be used to modify the ratings quantitatively. Here, data from the first two field seasons (2003-4) of our study in the Plumas National Forest (California, USA) are reported. Evaluations were performed in 240 measured plots and 510 songbird calling sites (3000 total assessments). Initial analysis placed 17% of the highest fire-spread category of ladder fuels, 22% in the second highest, 25% in the third, and 36% in the lowest. Evaluation and validation of this method using real fire data is a goal for the next year. Validation will allow us to link the assessed categories and quantified values based on them to actual probabilities of the fire spread up into the canopy.
Key words: fire ecology, forest fire fuels, forest canopy, fire spread