Climate drivers of regionally synchronous fires in the inland Northwest (1651–1900)
Emily K. Heyerdahl A G , Donald McKenzie B , Lori D. Daniels C , Amy E. Hessl D , Jeremy S. Littell E and Nathan J. Mantua FA UDSA Forest Service, Rocky Mountain Research Station, 5775 US West Highway 10, Missoula, MT 59808, USA.
B UDSA Forest Service, Pacific Northwest Research Station, 400 N 34th Street, Suite 201, Seattle, WA 98103, USA.
C University of British Columbia, Department of Geography, 1984 West Mall, Vancouver, BC V6T 1Z2, Canada.
D West Virginia University, Department of Geology and Geography, Box 6300, Morgantown, WV 26506, USA.
E University of Washington, College of Forest Resources, Box 352100, Seattle WA 98195-2100, USA.
F University of Washington, Climate Impacts Group, Box 354235, Seattle, WA 98195-4235, USA.
G Corresponding author. Email: eheyerdahl@fs.fed.us
International Journal of Wildland Fire 17(1) 40-49 https://doi.org/10.1071/WF07024
Submitted: 11 November 2006 Accepted: 10 August 2007 Published: 15 February 2008
Abstract
We inferred climate drivers of regionally synchronous surface fires from 1651 to 1900 at 15 sites with existing annually accurate fire-scar chronologies from forests dominated by ponderosa pine or Douglas-fir in the inland Northwest (interior Oregon, Washington and southern British Columbia). Years with widespread fires (35 years with fire at 7 to 11 sites) had warm spring–summers and warm-dry summers, whereas years with no fires at any site (18 years) had the opposite conditions. Spring climate likely affected the length of the fire season via the effects of snowmelt on soil and fuel moisture, whereas summer climate influenced fuel moisture during the fire season. Climate in prior years was not a significant driver of regionally synchronous surface fires, likely because fuels were generally sufficient for the ignition and spread of such fires in these forests. Fires occurred significantly more often than expected by chance when the El Niño–Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO) were both warm phase and less often when they were both cool phase. Interactions between large-scale climate patterns influenced fire synchrony in the inland Northwest because phases of ENSO and PDO were associated with changes in the frequency of warm-dry v. cool-wet spring–summer climate.
Additional keywords: British Columbia, El Niño–Southern Oscillation, fire scars, Oregon, Pacific Decadal Oscillation, Palmer Drought Severity Index, temperature, Washington.
Acknowledgements
We thank Rudy King for guidance on the statistical analysis. We thank Clint Wright for providing fire dates from his Teanaway site. We thank our many colleagues for their help in generating the fire-history chronologies we used in the present analysis. We thank the Helen Riaboff Whiteley Center of the University of Washington for providing the retreat where we began this analysis. We thank Penny Morgan, Tom Swetnam, and two anonymous reviewers for comments on the manuscript.
Baisan CH , Swetnam TW (1990) Fire history on a desert mountain range, Rincon Mountain Wilderness, Arizona, USA. Canadian Journal of Forest Research 20, 1559–1569.
| Crossref | GoogleScholarGoogle Scholar |
Brown TJ , Hall BL (1999) The use of t values in climatological composite analysis. Journal of Climate 12, 2941–2944.
| Crossref | GoogleScholarGoogle Scholar |
Galbraith WA , Anderson EW (1991) Grazing history of the Northwest. Rangelands 13, 213–218.
Grissino-Mayer HD (2001) FHX2 – Software for analyzing temporal and spatial patterns in fire regimes from tree rings. Tree-Ring Research 57, 115–124.
Hessl A, Miller J, Kernan J, Keenum D , McKenzie D (2007) Mapping wildfire boundaries from binary point data: comparing approaches. The Professional Geographer 59, 87–104.
| Crossref | GoogleScholarGoogle Scholar |
Heyerdahl EK, Brubaker LB , Agee JK (2002) Annual and decadal climate forcing of historical fire regimes in the interior Pacific Northwest. The Holocene 12, 597–604.
| Crossref | GoogleScholarGoogle Scholar |
Heyerdahl EK, Morgan P , Riser JP (in press) Multi-season climate synchronized widespread historical fires in dry forests (1630–1900), Northern Rockies, USA. Ecology ,
Kitzberger T, Brown PM, Heyerdahl EK, Swetnam TW , Veblen TT (2007) Contingent Pacific–Atlantic Ocean influence on multi-century wildfire synchrony over western North America. Proceedings of the National Academy of Sciences of the United States of America 104, 543–548.
| Crossref | GoogleScholarGoogle Scholar | PubMed |
McCabe GJ , Dettinger MD (1999) Decadal variability in the strength of ENSO teleconnections with precipitation in the western United States. International Journal of Climatology 19, 1399–1410.
| Crossref | GoogleScholarGoogle Scholar |
McKenzie D, Gedalof Z, Peterson DL , Mote P (2004) Climatic change, wildfire, and conservation. Conservation Biology 18, 890–902.
| Crossref | GoogleScholarGoogle Scholar |
Moore RD , McKendry IG (1996) Spring snowpack anomaly patterns and winter climatic variability, British Columbia, Canada. Water Resources Research 32, 623–632.
| Crossref | GoogleScholarGoogle Scholar |
Redmond KT , Koch RW (1991) Surface climate and streamflow variability in the western United States and their relationship to large-scale circulation indices. Water Resources Journal 27, 2381–2399.
| Crossref | GoogleScholarGoogle Scholar |
Seager R, Kushnir Y, Herweijer C, Naik N , Velez J (2005) Modeling of tropical forcing of persistent droughts and pluvials over western North America: 1856–2000. Journal of Climate 18, 4065–4088.
| Crossref | GoogleScholarGoogle Scholar |
Swetnam TW , Betancourt JL (1990) Fire–Southern Oscillation relations in the southwestern United States. Science 249, 1017–1020.
| Crossref | GoogleScholarGoogle Scholar | PubMed |
