HEAT-CONTENT VARIATION OF SIERRA-NEVADA CONIFERS

A study of fuels of Siena Nevada conifer species showed that percent a sh content, heat content with ash, and heat content without ash of nee dle and duff fuels significantly varied by species, fuel component, an d developmental stage of the overstory. Ash and heat contents of woody fuels varied by species and fuel component but not by developmental s tage. Bark fuels significantly differed by species, while no factor si gnificantly affected cone fuels. Regional variation in ash and heat co ntent was evident but small. However, the values reported here for hea t content with ash for fine fuels averaged 2.50 MJ kg(-1) higher than the standard values used in fire behavior prediction systems. Using st andard values can result in significant under predictions of fireline intensity of an average of 16 percent for all species of up to 47 perc ent for Pinus albicaulis.