Fire Behavior - Fuel Hazard
U.S. Department of the Interior (DOI), Bureau of Land Management (BLM), Idaho State Office
At best, predicting surface and canopy fuel loads from mid-scale data is problematic at best. The structure, composition, and arrangement of fuels are dependent upon the disturbance history of any given stand. Disturbance history includes natural processes (e.g., fire, wind, insects, and pathogens), as well as anthropogenic processes (e.g., silvicultural treatments and grazing practices). The only available proxy to the disturbance history (and consequently fuel loadings) available at a mid-scale level is the current structure and composition of vegetation (e.g., cover type, canopy cover, and size class). Unfortunately, the current structure and composition of vegetation is a very poor predictor of stand history. For example, stands having the same cover type, canopy cover, and size class may have substantially different histories; one could have been logged and the fuels cleaned up, and the other could have been impacted by mountain pine beetles.
Since the structure and composition of the current vegetation is a poor predictor of fuel loadings, we had Forest Service and BLM fuels specialist assign a very coarse qualitative ranking of "fuel hazard" (e.g., containment problems) to unique combinations of PVT and FBFM. The specific rule sets can be found in Table 24 of the "Idaho Interagency Assessment or Wildland Fire Risks to Communities: a Description of Methods". The specialists considered the following fire behavior attributes when making these assignments: ROS, fireline intensity, the potential for active crown fires, and the potential for spotting.Access these Data:ESRI GRID