Wildfire Patterns Change in Central Idaho's Ponderosa Pine-Douglas-fir Forest

Abstract Study of long-term fire histories (from fire scars on old trees) helps determine if severe fires were characteristic of the ponderosa pine (Pinus ponderosa) forests in central Idaho before the arrival of Euroamericans. Before 1895, all sample sites had average fire intervals of 10 to 22 years, implying a pattern of light to moderate surface fire. After 1895, fire intervals lengthened considerably, and severe fires became relatively common. Factors apparently influencing this change were a reduction in uncontrolled fires started by American Indians and Euroamericans; heavy livestock grazing that removed fine fuels; establishment of a fire suppression program; accumulation of slash from early logging; and development of dense conifer understories (ladder fuels). Applications of prescribed burning might reduce the risk of severe wildfires. West. J. Appl. For. 1:16-18, Jan, 1986