SIX CENTURIES OF FIRE HISTORY AT DEVILS TOWERNATIONAL MONUMENT WITH COMMENTS ON REGIONWIDE TEMPERATURE INFLUENCE

摘要

This study documents over six centuries of historic fire events at Devils Tower National Monument in northeast Wyoming, USA. The 691-year tree-ring chronology is based on 37 ponderosa pine (Pinus ponderosa C. Lawson) trees collected at the monument. The period of tree-ring record ranged in calendar years from 1312 to 2002 and fire scar dates (n = 129) ranged from 1330 to 1995. The mean fire interval (MFI) for the entire record was 24.6 years, and intervals for individual trees ranged from 4 to 119 years. A period of increased fire frequency (MFI = 5.7 years) occurred from about 1860 to 1880, corresponding to the period of Euro-American exploration and settlement of the region. Comparisons of fire-climate relationships derived from Devils Tower, the Black Hills, and other Great Plains sites suggest that Devils Tower pre settlement fire events were more similar to those of grasslands. Despite this, current fire intervals and vegetation assessments suggest that conditions are departed from historical conditions. In the Great Plains, temperature appears to be a strong regional-scale determinant of fire frequency, which may become more evident considering global warming predictions.