Fire Behavior Prediction (FBP) System
Introduction
The CFFDRS FBP system is not integrated into the U.S. fire behavior analysis tools, e.g., BehavePlus, FARSITE, FlamMap, WFDSS, or IFTDSS. Tools are available to U.S. users via the following:
- Field Guides (Alaska, Michigan, Minnesota)
- Online Calculators (AKFF, GLFF)
- Installable Software (REDapp)
This flowchart highlights the basic inputs and outputs for the FBP system, demonstrating many similarities to the US tools provided to support fire behavior prediction.
However, there are significant differences. Most important are the way that weather (fuel moisture and wind) and fuel (fuel types) are applied.
Weather Inputs
The ISI and BUI, drawn from the daily FWI system and adjusted for local conditions, are used directly as wind and fuel moisture inputs in fire behavior calculations. This facilitates the use of RAWS observations in fire behavior estimation.
FBP Fuel Types
Designed specifically for use in predicting the full range of fire behavior in northern forest ecosystems, there are 18 fuel types among five fuel groups. The classification recognizes coarse vegetative cover and structure types. Each CFFBP Fuel Type integrates the surface and canopy fuel characteristics, providing for evaluation of crown fire initiation and propagation without additional canopy characterizations.
An Excel workbook for comparing fuel types is available for download here.
Conifer Fuel Types
These fuel types represent the most important fire potential throughout the boreal forest. C-2 (spruce) and C-4 (pine) represent extreme potential with active crown fire anticipated under most conditions. C-3, C-5, and C-7 represent more moderate potential with taller trees and higher surface to canopy gaps.
Grass Fuel Types
These two grass fuel types are intended to differentiate between spring grass fuel beds (O-1a after snowmelt and late summer cured grass fuelbeds (O-1b). Their use requires characterization of the curing level in the grasses. They can be used for flammable grass/shrub fuelbeds, though generally require lower curing levels to properly slow spread rates.
Mixed Wood Fuel Types
Common to the Boreal Forest, these fuel types represent areas where varying combinations of conifers and hardwoods can support a range of crown fire potential ranging from torching trees to active crown fire. Use of these fuel types usually require assumption of the conifer percentage in the canopy fuels.
Deciduous Fuel Types
These fuel types were calibrated to largely pure stands of Trembling Aspen and/or Paper Birch. They may over-estimate potential in northern hardwood stand of the eastern U.S. and underestimate potential in oak dominated central hardwoods of the eastern and central U.S.
Slash Fuel Types
Calibrated to post-logging fuelbeds with substantial fuel loads, they may or may not effectively represent blowdown areas.
Example Fire Behavior Lookup Table
FBP Lookup tables can be found in the Field Guides (AK, MI, MN) that can be downloaded at the links below or at the top of the section. This example shows that spread rates, flame lengths, and fire type can be determined once the user has identified the fuel type, the ISI, and the BU( or grass curing for open types.
