Wildfire Heterogeneity: Empirical vs. Simulated Observations—The Carmel 2010 Wildfire as a Case Study

Abstract

Three general factors affect wildfire behavior and outcome: vegetation properties, weather patterns during the wildfire and topography. A heterogeneous landscape emerges from the interactions among these factors in open and natural areas following wildfires. Herein, an attempt is made to analyze the spatial heterogeneity of the Carmel 2010 fire using aerial photographs and fire spread simulation models. Additionally, simulation models were used to assess the sensitivity of fire properties to variations in foliar moisture content and wind speed. Image analysis results indicate that broadleaved communities in the Carmel region are less flammable compared to pine stands, resulting in larger areas of undamaged vegetation within the extent of the burned area. Once a vegetation patch is burned, however, the proportion of the area severely affected by the fire is not fundamentally different, with 64.6% of the trees severely damaged in the pine stands, compared to 60.5% in the broadleaved stands. Simulation results also suggest that flame height and variance is higher in the pine stands compared to other vegetation communities. Further, simulation results indicate that the fire event was more sensitive to wind speed than to foliar moisture content. Increasing wind speed from 8 to 40 km/h resulted in a 2.5-fold average increase in flame heights and a 50% decrease in the coefficient of variation, compared to an irregular response observed following manipulations of foliar moisture content. Consequently, it is suggested that extreme conditions generate more severe damage and result in lower landscape heterogeneity.

Keywords:

• Carmel 2010 wildfire
• fire spread simulation models
• image analysis
• landscape heterogeneity