Abstract
In this paper we discuss the first phase of a 3-year effort to document the fire history of Yellowstone National Park's (YNP) Lamar River drainage southeast of Soda Butte Creek. The overall goal of the study was to provide managers with a more complete understanding of YNP natural fire regimes. Specific objectives were: 1. Determine natural (pre-1900) fire periodicities, severities, burning patterns, and post-fire succession within the study area's major forest types (Douglas fir/ grassland, lodgepole pine/subalpine fir/ spruce, whitebark pine/lodgepole pine/ subalpine fir, and whitebark pine/subalpine fir timberline habitats); 2. document and map the pre-1988 forest age-class mosaic; and 3. digitize the age-class mosaic map for the YNP's GIS data base. This study is considered especially timely because the 1988 fires destroyed much evidence of area fire history. Our sampling in 1989 focused on a 24,000 ha area encompassing the Cache Creek drainage, which was severely burned in 1988. The forest age-class mosaic was sampled by increment boring and sawing fire scar samples from old trees (Arno and Sneck 1977, Barrett and Arno 1988). Aerial photographs were used to map the pre-1988 forest age-class mosaic; Data was digitized for the park's GIS data base. Information from the YNP fire atlas also was useful in interpreting fire patterns during the post-1900 period.