Fire Regimes on the Clearwater and Nez Perce National Forests North-Central Idaho

During the summer of 1993, fire history sampling was conducted in several analysis areas on the Clearwater and Nez Perce National Forests in north central Idaho. The goal was to determine fire regime patterns for major forest types in order to aid the development of strategies for ecosystem management. Because this large area contains considerable vegetative diversity, objectives were to select several representative sample areas and determine pre-19OO fire history, and determine the possible effects of post-19OO fire suppression. Three sample areas were chosen after consulting with national forest personnel. The first area was 1n a relatively high elevation old growth forest dominated by lodgepole pine and subalpine fir, adjacent to the northeastern portion of the Selway-Bitterroot Wilderness. Two low elevation analysis areas also were selected, one in highly productive mesic forests (red cedar and grand fir potential climax) in the North Pork Clearwater River drainage, and one in a warmer and drier zone dominated by ponderosa pine, Douglas-fir, and grand fir (Douglas-fir and grand fir potential climax) in the South Pork Clearwater River drainage. After data analysis, results from this sampling were factored into a previous fire regimes model that resulted after work in and around the Selway­Bitterroot Wilderness (Barrett and Arno 1991). North-central Idaho contains a wide range of vegetation types and also represents a major north-south transition zone between relatively dry and relatively moist forest types in Idaho, Consequently, the fire regimes model presented in this report is somewhat preliminary, pending possible addition of future data and an upcoming classification for Inland Northwest forests (ongoing work by author in conjunction with Intermountain Research Station; projected 1996 completion date).