Fire and Environmental Research Applications Team

Cedar River Fire Hazard Analysis and Fuel Decomposition

FERA recently completed a fire hazard analysis and a fuel decomposition study for the Cedar River Municipal Watershed (CRMW). CRMW is approximately 31 miles east-southeast of Seattle, Washington near the town of North Bend, WA.

Fire Hazard

Fire hazard in the CRMW was assessed to help reconcile ecological restoration efforts and fire management with respect to fuel loadings across the landscape. Specifically the assessment:

• Characterized vegetation patterns and distribution,
• Described and quantified current and potential wildfire hazard
• Developed and simulated potential thinnings and surface fuel treatments to identify options for addressing and minimizing fire hazard, and
• Developed maps of current and predicted fire hazard.

The Fire and Fuels Extension to the Forest Vegetation Simulator (FFE-FVS) was used to quantify fuels for different forest classifications and to predict the characteristics and effects of a fire should one occur during warm, dry weather conditions.

Fuel Decomposition

Fuel decomposition was measured to provide fine-scale temporal data on fuel succession that will inform the coarse-scale assessment of fire hazard for different management options. Specifically the objectives of this study were:

• Quantify fuelbed characteristics (e.g., fuelbed loadings and fuelbed depth) in stands that were thinned at different times,
• Examine the effect of surface fuel treatments on fuelbed characteristics, and
• Estimate fuel loading residence time.

Transects were done to measure fuelbed loading (i.e., tons per acre) and fuelbed depth in stands treated from 2001-2005. Mean loading per size class and mean fuelbed depth were calculated in DRA program (see figure below). A Pacific silver fir decomposition constant or fractional loss rate (percentage lost per year) was used to estimate the residence time of fuel loading after treatment.

Linking the Forest Vegetation Simulator and the Fuel Characteristic Classification System

See FCCS Applications

Team Lead: Morris Johnson

This research was funded by the City of Seattle