ISORHYTHMIC ANALYSIS OF FOREST-FIRE FUELBED ARRAYS

Isarithmic analysis, a cartographic technique, was used for mapping tw o structurally distinct forest fire fuelbeds. Method-produced errors a nd statistical validity of isarithmically-created surfaces for fuel lo adings and depths were determined and analyzed. The isarithmic method- produced error is a function of data sampling scheme, spatial interpol ation model, and spatial variability of the phenomenon mapped. Using a n unaligned stratified random design and kriging interpolation, error produced by the isarithmic method was proportional to (sample size)-0. 20 times an intercept coefficient that directly reflected variance of each fuel parameter interpolated. As a result, the magnitude of error decreased, at a decreasing rate, with increasing sample size; fuel par ameters that exhibited high spatial variability also had higher magnit udes of error due to larger intercept values. Four or nine sample poin ts were too few for use in the isarithmic mapping of the fuel types ex amined and a minimum of sixteen points was required. The analytical sc heme presented here could yield more reliable information on the eleme nts that compose the forest fire environment.