Description

FSPro uses the Energy Release Component (ERC) for fuel model G to derive fire weather percentiles which are used to bin fuel moisture and other inputs to the model. ERC is part of the National Fire Danger Rating System (NFDRS) which is used in the lower 48 states but does not perform as well as the Canadian Forest Fire Danger Rating System (CFFDRS) Build-up Index (BUI) in Alaska's boreal forest types. Energy Release Component is the potential available energy per square foot of flaming fire at the head of the fire and is expressed in units of BTUs per square foot. ERC for fuel model G used by FSPro involves moisture inputs for the entire fuel complex, i.e., 1-hr, 10-hr, 100-hr, 1000-hr, and the live fuel moisture. The Buildup Index (BUI) is a numeric rating of the total amount of fuel available for combustion. It describes moisture conditions in the dead moss and upper duff layers, approximately 3-15 cm from the surface. ERC and BUI perform roughly the same function in their respective fire danger rating systems, representing moisture conditions at the scale of days to weeks. However there are some key differences. ERC is an index designed to track cylindrical fuels particles, e.g., twigs, branches, logs, and live herbaceous and shrub fuels. BUI is an index designed to track stratified layers of fuel: live moss, dead moss, and duff. Previous LTANs in Alaska have expressed some skepticism in using ERC in place of BUI. This analysis provides insight to the overall problem by addressing a specific fire in Alaska, the 2009 Titna River Fire (420) using the Minchumina RAWS (500623).