Biologists have long recognized that fire historically has had strong influence on the ecology of Northern Rocky Mountain forests (Intermountain Fire Research Council 1970; Habeck and Mutch 1973). However, there is little data on frequency and severity of fires in the various forest types before organized fire suppression evolved in the early 1900's. Thus, questions and conjecture have arisen about the patterns and types of fires that occurred: highly destructive crown fires at long intervals or creeping ground fires at short intervals. Confounding this problem are great differences among the types of forests found in this region (R. and J. Daubenmire 1968; Pfister and others, in press) and probably among their respective "fire ecologies." A review of the literature dealing with fire in the Northern Rocky Mountains is provided by Wellner (1970) and is updated by Arno.1

The present study was developed to provide detailed information on historical fire in one small portion of the Northern Rockies. Specifically, the goal was to determine historical frequencies, intensities, and influences of fire on stand structure and composition in various forest types found on the Bitterroot National Forest in west-central Montana. A knowledge of the workings and results of the historical fire regime is an essential element in describing forest ecosystems, development of management alternatives, and planning subsequent programs and projects.

1Arno, Stephen F. Investigation of fire history in the Bitterroot Range, Montana. (In preparation)