SUBALPINE FOREST FIRE HISTORY: EVIDENCE FOR MIXED SEVERITY FIRE REGIMES IN MIXED-CONIFER AND LODGEPOLE PINE FORESTS IN WESTERN MONTANA.

SUTHERLAND, E.K., E.T. ZIEGLER, E.A. MACE, AND E.K. HEYERDAHL

In the northern ( U.S.) Rockies, subalpine forests grow in harsh environments (cold and dry), with snowy winters and dry summers. Fire regimes are tied to a larger disturbance complex of drought, insect infestation, fire, and regeneration. Accordingly, fire regimes are described as mixed-severity – a gradient of low severity fires with occasional torching of individual trees to widespread stand-replacing fire. Knowledge about the scales of activity (temporal and spatial) among drought, insects, fire, and regeneration is lacking, but needed, for management of water, fisheries, and hazardous fuels. Here we present the history and spatial scale of fire in seven headwater drainages in western Montana dominated by mixed-conifer and lodgepole pine. Our evidence includes crossdated fire-scar histories as well as stand demographies and comparison to climate, insect (where available) and wildfire records.