Appraising fuels and flammability in western aspen: a prescribed fire guide

This file was created by scanning the printed publication. Errors identified by the software have been corrected; however, some errors may remain. he did research on field measurement of fuel properties and fire-danger rating systems while with the Lake States Forest Experiment Station. In 1965, he transferred to the Intermountain Fire Sciences Laboratory, Missoula, MT, where he conducted research on the physical properties, inventory, and prediction of fuels. Since 1979, he has been leader of a project that investigates fire effects and use. DENNIS G. SIMMERMAN is a forester with the Fire Effects and Use research work unit at the Intermountain Fire Sciences Laboratory. Previously he worked with the Fire Technology research work unit. He earned a B.S. degree in forestry from the University of Arizona. ACKNOWLEDGMENT The competent and enthusiastic assistance of several individuals contributed materially to this publication. They are Station. Their technical suggestions, locating of study areas, and rating of fire potentials are greatly appreciated. Patricia Andrew's assistance in developing the fire prediction methodology was especially helpful. This report explains how to appraise fuels and flam-mability in aspen forests as a means for choosing good opportunities for prescribed burning and for determining the environmental conditions favorable for a successful burn. The appraisal process is based on a study of physical fuel properties and vegetation occurring in southeastern Idaho and western Wyoming. Fuels were classified into five types: aspen/shrub, aspen/tall forb, aspen/low forb, mixed/ shrub, and mixedlforb, based on overstory composition , shrub coverage, and quantity of herbaceous vegetation. The fuel types are illustrated with color photographs accompanied by information on fuel loadings, vegetational characteristics, adjective fire behavior ratings , and ratings for probability of a successful burn. To aid in writing fire prescriptions the report includes tables of predicted fireline intensity and rate of spread as a function of fine fuel moisture content, vegetation curing, windspeed, and slope. Grazing reduced fire behavior potential by 80 to 90 percent of ungrazed conditions. The authors discuss how fire behavior is affected by downed woody fuel accumulations, leaf fall, small conifers, canopy closure , and rodent activity. Adjective ratings of fire intensity, rate of spread, torching, and resistance to contol incorporate the influence of downed woody fuel accumulations and conifers. The aspen/shrub type is the most flammable, followed by mixed/shrub. The aspen/tall forb is intermediate in flammabilty and has about one-half of the fire intensity potential of aspen/shrub. The aspen/low …

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