Free Standard AU & NZ Shipping For All Book Orders Over $80!
Register      Login
International Journal of Wildland Fire International Journal of Wildland Fire Society
Journal of the International Association of Wildland Fire
RESEARCH ARTICLE

Late Holocene fire–climate relationships of the western San Juan Mountains, Colorado

Erica R. Bigio A C , Thomas W. Swetnam A and Philip A. Pearthree B
+ Author Affiliations
- Author Affiliations

A Laboratory of Tree-Ring Research, 1215 E. Lowell St., University of Arizona, Tucson, AZ 85721, USA.

B Arizona Geological Survey, 1955 E. Sixth Street, PO Box 210184, Tucson, AZ 85721, USA.

C Corresponding author. Email: ebigio@email.arizona.edu

International Journal of Wildland Fire 26(11) 944-962 https://doi.org/10.1071/WF16204
Submitted: 9 November 2016  Accepted: 6 August 2017   Published: 27 October 2017

Abstract

In recent decades, warming temperatures and severe drought have contributed to large and severe wildfires in the south-western United States. To put current wildfires in a long-term context, we reconstructed fire events with alluvial stratigraphy methods in south-western Colorado, and compared with paleoclimate records over the late Holocene. The chronology of 32 fire-related sedimentation events from six tributary basins was established using 48 radiocarbon dates. Based on deposit characteristics, we found episodes of increased high-severity fire for 2750–2350 cal yr BP (800–400 BCE); 1400–1175 cal yr BP (550–775 CE); 1050–700 cal yr BP (900–1250 CE); and 525–250 cal yr BP (1425–1700 CE). There were peaks in low-severity fires in 2350–2000 cal yr BP (400–50 BCE) and 300–70 cal yr BP (1650–1880 CE). Two of the four episodes of high-severity fire corresponded with multi-decadal droughts, including clusters of extreme drought years. The most recent fire episode was preceded by wetter conditions and decreased frequency of extreme drought years, which facilitated the build-up of fuel loads. However, previous high-severity episodes were not consistently preceded by wetter conditions. Steep slopes and overall rugged terrain were also likely contributing factors to fuel accumulation and high-severity fires. A recent wildfire followed a fire-free interval of greater than 120 years and likely contained more extensive areas of high-severity burned area than fire events over the late Holocene.

Additional keywords: alluvial sediments, fire history, fire-related debris flow, mixed conifer, ponderosa pine.


References

Allen CD, Savage M, Falk DA, Suckling KF, Swetnam TW, Schulke T, Stacey PB, Morgan P, Hoffman M, Klingel JT (2002) Ecological restoration of Southwestern ponderosa pine ecosystems: a broad perspective. Ecological Applications 12, 1418–1433.
Ecological restoration of Southwestern ponderosa pine ecosystems: a broad perspective.Crossref | GoogleScholarGoogle Scholar |

Allen CD, Anderson RS, Jass RB, Toney JL, Baisan CH (2008) Paired charcoal and tree-ring records of high-frequency Holocene fire from two New Mexico bog sites. International Journal of Wildland Fire 17, 115–130.
Paired charcoal and tree-ring records of high-frequency Holocene fire from two New Mexico bog sites.Crossref | GoogleScholarGoogle Scholar |

Anderson RS, Allen CD, Toney JL, Jass RB, Bair AN (2008) Holocene vegetation and fire regimes in subalpine and mixed conifer forests, southern Rocky Mountains, USA. International Journal of Wildland Fire 17, 96–114.
Holocene vegetation and fire regimes in subalpine and mixed conifer forests, southern Rocky Mountains, USA.Crossref | GoogleScholarGoogle Scholar |

Armour J, Fawcett PJ, Geissman JW (2002) 15 k.y. paleoclimatic and glacial record from northern New Mexico. Geology 30, 723–726.
15 k.y. paleoclimatic and glacial record from northern New Mexico.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD38XmvVSrsr4%3D&md5=08ca43bd9ca670033bb1664c56aae5f8CAS |

Asmerom Y, Polyak V, Burns S, Rassmussen J (2007) Solar forcing of Holocene climate: new insights from a speleothem record, southwestern United States. Geology 35, 1
Solar forcing of Holocene climate: new insights from a speleothem record, southwestern United States.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXhtVSiu7vE&md5=fa19dd2af85256dfcd8e580d178025f5CAS |

Bigio E, Swetnam TW, Baisan CH (2010) A comparison and integration of tree-ring and alluvial records of fire history at the Missionary Ridge fire, Durango, Colorado, USA. The Holocene 20, 1047–1061.
A comparison and integration of tree-ring and alluvial records of fire history at the Missionary Ridge fire, Durango, Colorado, USA.Crossref | GoogleScholarGoogle Scholar |

Bigio ER, Swetnam TW, Baisan CH (2016) Local-scale and regional climate controls on historical fire regimes in the San Juan Mountains, Colorado. Forest Ecology and Management 360, 311–322.
Local-scale and regional climate controls on historical fire regimes in the San Juan Mountains, Colorado.Crossref | GoogleScholarGoogle Scholar |

Blair RW, Gillam M (2011) Geomorphic history of the San Juan Mountains. In ‘The Eastern San Juan Mountains: Their Geology, Ecology and Human History’. (Eds RW Blair, G Bracksieck) pp. 61–78. (University of Colorado Press: Boulder, CO, USA)

Breshears DD, Cobb NS, Rich PM, Price KP, Allen CD, Balice RG, Romme WH, Kastens JH, Floyd ML, Belnap J, Anderson JJ, Myers OB, Meyer CW (2005) Regional vegetation die-off in response to global-change-type drought. Proceedings of the National Academy of Sciences of the United States of America 102, 15144–15148.
Regional vegetation die-off in response to global-change-type drought.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2MXhtFGqtb3I&md5=87615e826291fba1fce5f84097fe8fb9CAS |

Brown PM, Wu R (2005) Climate and disturbance forcing of episodic tree recruitment in a southwestern ponderosa pine landscape. Ecology 86, 3030–3038.
Climate and disturbance forcing of episodic tree recruitment in a southwestern ponderosa pine landscape.Crossref | GoogleScholarGoogle Scholar |

Calder WJ, Parker D, Stopka CJ, Jiménez-Moreno G, Shuman BN (2015) Medieval warming initiated exceptionally large wildfire outbreaks in the Rocky Mountains. Proceedings of the National Academy of Sciences of the United States of America 112, 13261–13266.
Medieval warming initiated exceptionally large wildfire outbreaks in the Rocky Mountains.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC2MXhs1SqurzP&md5=ae50b4cbf383ca7eccd28517ddbc9510CAS |

Cannon SH, Powers PS, Savage WZ (1998) Fire-related hyperconcentrated and debris flows on Storm King Mountain, Glenwood Springs, Colorado, USA. Environmental Geology 35, 210–218.
Fire-related hyperconcentrated and debris flows on Storm King Mountain, Glenwood Springs, Colorado, USA.Crossref | GoogleScholarGoogle Scholar |

Cannon SH, Bigio ER, Mine E (2001) A process for fire-related debris flow initiation, Cerro Grande fire, New Mexico. Hydrological Processes 15, 3011–3023.
A process for fire-related debris flow initiation, Cerro Grande fire, New Mexico.Crossref | GoogleScholarGoogle Scholar |

Cannon SH, Gartner JE, Holland-Sears A, Thurston BM, Gleason JA (2003) Debris-flow response of basins burned by the 2002 Coal Seam and Missionary Ridge fires, Colorado. In ‘Engineering Geology in Colorado – Contributions, Trends, and Case Histories: Association of Engineering Geologists Special Publication 14’ (Colorado Geological Survey Special Publication 55). (Eds DD Boyer, PM Santi, WP Rogers) Available at http://citeseerx.ist.psu.edu/viewdoc/download?doi= 10.1.1.586.4773&rep=rep1&type=pdf [Accessed 25 September 2017]

Cannon SH, Gartner JE, Wilson RC, Bowers JC, Laber JL (2008) Storm rainfall conditions for floods and debris flows from recently burned areas in southwestern Colorado and southern California. Geomorphology 96, 250–269.
Storm rainfall conditions for floods and debris flows from recently burned areas in southwestern Colorado and southern California.Crossref | GoogleScholarGoogle Scholar |

Cannon SH, Gartner JE, Rupert MG, Michael JA, Rea AH, Parrett C (2010) Predicting the probability and volume of postwildfire debris flows in the intermountain western United States. Geological Society of America Bulletin 122, 127–144.
Predicting the probability and volume of postwildfire debris flows in the intermountain western United States.Crossref | GoogleScholarGoogle Scholar |

Carroll CJ, Gillam M, Ruf JC, Loseke TD, Kirkham RM (1999) ‘Geologic Map of the Durango East Quadrangle, La Plata County, Colorado.’ (Colorado Geological Survey: Denver, CO, USA)

Conroy JL, Overpeck JT, Cole JE, Shanahan TM, Steinitz-kannan M (2008) Holocene changes in eastern tropical Pacific climate inferred from a Galapagos lake sediment record. Quaternary Science Reviews 27, 1166–1180.
Holocene changes in eastern tropical Pacific climate inferred from a Galapagos lake sediment record.Crossref | GoogleScholarGoogle Scholar |

Cook ER, Meko DM, Stahle DW, Cleveland MK (2008) North American summer PDSI reconstructions, Version 2a. IGBP PAGES/World Data Center for Paleoclimatology Data Contribution Series # 2008–046. (NOAA/NGDC Paleoclimatology Program: Boulder, CO, USA) Available at ftp://ftp.ncdc.noaa.gov/pub/data/paleo/ drought/NAmericanDroughtAtlas.v2/ [Accessed 24 September 2017]

Cook ER, Woodhouse CA, Eakin CM, Meko DM, Stahle DW (2004) Long-term aridity changes in the western United States. Science 306, 1015–1018.
Long-term aridity changes in the western United States.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2cXptFyjur4%3D&md5=f8143299678f5b59ad268ddecb8787c0CAS |

Cook ER, Seager R, Heim Jr RR, Vose RS, Herweijer C, Woodhouse C (2010) Megadroughts in North America: placing IPCC projections of hydroclimatic change in a long-term palaeoclimate context. Journal of Quaternary Science 25, 48–61.
Megadroughts in North America: placing IPCC projections of hydroclimatic change in a long-term palaeoclimate context.Crossref | GoogleScholarGoogle Scholar |

Costa JE (1988) Rheologic, geomorphic and sedimentologic differentiation of water floods, hyperconcentrated flows, and debris flows. In ‘Flood Geomorphology’ (Eds VR Baker, RC Kochel, PC Patton) pp. 113–122. (Wiley-Intersciences: New York, NY, USA)

Dillon GK, Holden ZA, Morgan P, Crimmins MA, Heyerdahl EK, Luce CH (2011) Both topography and climate affected forest and woodland burn severity in two regions of the western US, 1984 to 2006. Ecosphere 2, art130
Both topography and climate affected forest and woodland burn severity in two regions of the western US, 1984 to 2006.Crossref | GoogleScholarGoogle Scholar |

Fall PL (1997) Timberline fluctuations and late Quaternary paleoclimates in the southern Rocky Mountains, Colorado. Geological Society of America Bulletin 109, 1306–1320.
Timberline fluctuations and late Quaternary paleoclimates in the southern Rocky Mountains, Colorado.Crossref | GoogleScholarGoogle Scholar |

Fitch EP (2012) Holocene fire-related alluvial chronology and geomorphic implications in the Jemez Mountains, New Mexico. MSc Thesis, University of New Mexico, Albuquerque, NM, USA.

Fitch EP, Meyer GA (2016) Temporal and spatial climatic controls on Holocene fire-related erosion and sedimentation, Jemez Mountains, New Mexico. Quaternary Research 85, 75–86.
Temporal and spatial climatic controls on Holocene fire-related erosion and sedimentation, Jemez Mountains, New Mexico.Crossref | GoogleScholarGoogle Scholar |

Frechette JD, Meyer GA (2009) Holocene fire-related alluvial-fan deposition and climate in ponderosa pine and mixed-conifer forests, Sacramento Mountains, New Mexico, USA. The Holocene 19, 639–651.
Holocene fire-related alluvial-fan deposition and climate in ponderosa pine and mixed-conifer forests, Sacramento Mountains, New Mexico, USA.Crossref | GoogleScholarGoogle Scholar |

Fulé PZ, Covington WW, Moore MM (1997) Determining reference conditions for ecosystem management of southwestern ponderosa pine forests. Ecological Applications 7, 895–908.
Determining reference conditions for ecosystem management of southwestern ponderosa pine forests.Crossref | GoogleScholarGoogle Scholar |

Fulé PZ, Korb JE, Wu R (2009) Changes in forest structure of a mixed conifer forest, southwestern Colorado, USA. Forest Ecology and Management 258, 1200–1210.
Changes in forest structure of a mixed conifer forest, southwestern Colorado, USA.Crossref | GoogleScholarGoogle Scholar |

Gabet E, Bookter A (2008) A morphometric analysis of gullies scoured by post-fire progressively bulked debris flows in southwest Montana, USA. Geomorphology 96, 298–309.
A morphometric analysis of gullies scoured by post-fire progressively bulked debris flows in southwest Montana, USA.Crossref | GoogleScholarGoogle Scholar |

Gartner JE, Cannon SH, Santi PM, Dewolfe VG (2008) Empirical models to predict the volumes of debris flows generated by recently burned basins in the western U.S. Geomorphology 96, 339–354.
Empirical models to predict the volumes of debris flows generated by recently burned basins in the western U.S.Crossref | GoogleScholarGoogle Scholar |

Graham NE, Hughes MK (2007) Reconstructing the Mediaeval low stands of Mono Lake, Sierra Nevada, California, USA. The Holocene 17, 1197–1210.
Reconstructing the Mediaeval low stands of Mono Lake, Sierra Nevada, California, USA.Crossref | GoogleScholarGoogle Scholar |

Graham NE, Hughes MK, Ammann CM, Cobb KM, Hoerling MP, Kennett DJ, Kennett JP, Rein B, Stott L, Wigand PE, Xu T (2007) Tropical Pacific – mid-latitude teleconnections in medieval times. Climatic Change 83, 241–285.
Tropical Pacific – mid-latitude teleconnections in medieval times.Crossref | GoogleScholarGoogle Scholar |

Grissino-Mayer HD, Romme WH, Floyd ML, Hanna DD (2004) Climatic and human influences on fire regimes of the southern San Juan Mountains, Colorado, USA. Ecology 85, 1708–1724.
Climatic and human influences on fire regimes of the southern San Juan Mountains, Colorado, USA.Crossref | GoogleScholarGoogle Scholar |

Haffey CM (2014) Patterns and predictors of crown fire induced type conversion in dry conifer forests. MSc Thesis, Department of Environmental Sciences and Policy, Northern Arizona University, Flagstaff, AZ, USA.

Herweijer C, Seager R, Cook ER, Emile-Geay J (2007) North American droughts of the last millennium from a gridded network of tree-ring data. Journal of Climate 20, 1353–1376.
North American droughts of the last millennium from a gridded network of tree-ring data.Crossref | GoogleScholarGoogle Scholar |

Holden ZA, Morgan P, Crimmins MA, Steinhorst RK, Smith AMS (2007) Fire season precipitation variability influences fire extent and severity in a large southwestern wilderness area, United States. Geophysical Research Letters 34, L16708
Fire season precipitation variability influences fire extent and severity in a large southwestern wilderness area, United States.Crossref | GoogleScholarGoogle Scholar |

Iniguez JM, Swetnam TW, Baisan CH (2009) Spatially and temporally variable fire regime on Rincon Peak, Arizona, USA. Fire Ecology 5, 3–21.
Spatially and temporally variable fire regime on Rincon Peak, Arizona, USA.Crossref | GoogleScholarGoogle Scholar |

Jenkins SE, Sieg CH, Anderson DE, Kaufman DS, Pearthree PA (2011) Late Holocene geomorphic record of fire in ponderosa pine and mixed-conifer forests, Kendrick Mountain, northern Arizona, USA. International Journal of Wildland Fire 20, 125–141.
Late Holocene geomorphic record of fire in ponderosa pine and mixed-conifer forests, Kendrick Mountain, northern Arizona, USA.Crossref | GoogleScholarGoogle Scholar |

Kelly R, Chipman ML, Higuera PE, Stefanova I, Brubaker LB, Hu FS (2013) Recent burning of boreal forests exceeds fire regime limits of the past 10 000 years. Proceedings of the National Academy of Sciences of the United States of America 110, 13055–13060.
Recent burning of boreal forests exceeds fire regime limits of the past 10 000 years.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3sXhsVSjsb7K&md5=e84be6b84023b496588003fa41049a3fCAS |

Korb JE, Wu RY (2011) Fire, climate and forest health. ‘The Eastern San Juan Mountains: Their Geology, Ecology and Human History.’ (Eds RW Blair, G Bracksieck) pp. 151–172. (University of Colorado Press: Boulder, CO, USA)

Korb JE, Fulé PZ, Wu R (2013) Variability of warm/dry mixed conifer forests in southwestern Colorado, USA: implications for ecological restoration. Forest Ecology and Management 304, 182–191.
Variability of warm/dry mixed conifer forests in southwestern Colorado, USA: implications for ecological restoration.Crossref | GoogleScholarGoogle Scholar |

Margolis EQ, Balmat J (2009) Fire history and fire–climate relationships along a fire regime gradient in the Santa Fe municipal watershed, NM, USA. Forest Ecology and Management 258, 2416–2430.
Fire history and fire–climate relationships along a fire regime gradient in the Santa Fe municipal watershed, NM, USA.Crossref | GoogleScholarGoogle Scholar |

Margolis EQ, Meko DM, Touchan R (2011) A tree-ring reconstruction of streamflow in the Santa Fe River, New Mexico. Journal of Hydrology 397, 118–127.
A tree-ring reconstruction of streamflow in the Santa Fe River, New Mexico.Crossref | GoogleScholarGoogle Scholar |

Marlon JR, Bartlein PJ, Gavin DG, Long CJ, Anderson RS, Briles CE, Brown KJ, Colombaroli D, Hallett DJ, Power MJ, Scharf EA, Walsh MK (2012) Long-term perspective on wildfires in the western USA. Proceedings of the National Academy of Sciences of the United States of America 109, E535–E543.
Long-term perspective on wildfires in the western USA.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38XksVyhu7g%3D&md5=674ea336b71aaf5c3991440c00d317acCAS |

Meko DM, Woodhouse CA, Baisan CA, Knight T, Lukas JJ, Hughes MK, Salzer MW (2007) Medieval drought in the upper Colorado River Basin. Geophysical Research Letters 34, L10705
Medieval drought in the upper Colorado River Basin.Crossref | GoogleScholarGoogle Scholar |

Meyer GA, Wells SG (1997) Fire-related sedimentation on alluvial fans, Yellowstone National Park, U.S.A. Journal of Sedimentary Research 67, 776–791.

Meyer GA, Wells SG, Jull AJT (1995) Fire and alluvial chronology in Yellowstone National Park : climatic and intrinsic controls on Holocene geomorphic processes. Geological Society of America Bulletin 107, 1211–1230.
Fire and alluvial chronology in Yellowstone National Park : climatic and intrinsic controls on Holocene geomorphic processes.Crossref | GoogleScholarGoogle Scholar |

Miller JD, Safford HD, Crimmins M, Thode AE (2009) Quantitative evidence for increasing forest fire severity in the Sierra Nevada and Southern Cascade Mountains, California and Nevada, USA. Ecosystems 12, 16–32.
Quantitative evidence for increasing forest fire severity in the Sierra Nevada and Southern Cascade Mountains, California and Nevada, USA.Crossref | GoogleScholarGoogle Scholar |

Monitoring Trends in Burn Severity (MTBS) (2017) MTBS data access: fire level geospatial data. MTBS Project (USDA Forest Service/US Geological Survey). Available at http://mtbs.gov [Accessed 24 September 2017]

Nelson NA, Pierce J (2010) Late-Holocene relationships among fire, climate and vegetation in a forest-sagebrush ecotone of southwestern Idaho, USA. The Holocene 20, 1179–1194.
Late-Holocene relationships among fire, climate and vegetation in a forest-sagebrush ecotone of southwestern Idaho, USA.Crossref | GoogleScholarGoogle Scholar |

O’Connor CD, Falk DA, Lynch AM, Swetnam TW (2014) Fire severity, size, and climate associations diverge from historical precedent along an ecological gradient in the Pinaleño Mountains, Arizona, USA. Forest Ecology and Management 329, 264–278.
Fire severity, size, and climate associations diverge from historical precedent along an ecological gradient in the Pinaleño Mountains, Arizona, USA.Crossref | GoogleScholarGoogle Scholar |

Park Williams A, Allen CD, Macalady AK, Griffin D, Woodhouse CA, Meko DM, Swetnam TW, Rauscher SA, Seager R, Grissino-Mayer HD, Dean JS, Cook ER, Gangodagamage C, Cai M, McDowell NG (2013) Temperature as a potent driver of regional forest drought stress and tree mortality. Nature Climate Change 3, 292–297.
Temperature as a potent driver of regional forest drought stress and tree mortality.Crossref | GoogleScholarGoogle Scholar |

Pielke Sr RA, Doesken N, Bliss O, Green T, Chaffin C, Salas JD, Woodhouse CA, Lukas JJ, Wolter K (2005) Drought 2002 in Colorado: an unprecedented drought or a routine drought? Pure and Applied Geophysics 162, 1455–1479.
Drought 2002 in Colorado: an unprecedented drought or a routine drought?Crossref | GoogleScholarGoogle Scholar |

Pierce JL, Meyer GA, Jull AJT (2004) Fire-induced erosion and millennial-scale climate change in northern ponderosa pine forests. Nature 432, 87–90.
Fire-induced erosion and millennial-scale climate change in northern ponderosa pine forests.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2cXpt1eitLo%3D&md5=6715cf26c09f819f7d463f786b26f1a0CAS |

Poling M (2016) ‘Trends in burn severity in the southwestern USA from 1984–2013.’ MSc Thesis, Department of Forestry, Northern Arizona University, Flagstaff, AZ, USA.

Reimer P, Baillie M, Bard E, Bayliss A, Beck J, Blackwell P, Bronk Ramsey C, Buck C, Burr G, Edwards R, Friedrich M, Grootes P, Guilderson T, Hajdas I, Heaton T, Hogg A, Hughen K, Kaiser K, Kromer B, McCormac F, Manning S, Reimer R, Richards D, Southon J, Talamo S, Turney C, van der Plicht J, Weyhenmeyer C (2009) IntCal09 and Marine09 radiocarbon age calibration curves, 0–50,000 years cal BP. Radiocarbon 51, 1111–1150.
IntCal09 and Marine09 radiocarbon age calibration curves, 0–50,000 years cal BP.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXivVamur0%3D&md5=70788de0e56091f1f6d676699e4ee67dCAS |

Roos CI (2008) Fire, climate and social-ecological systems in the ancient southwest: alluvial geoarchaeology and applied historical ecology. PhD Dissertation, Department off Anthropology, University of Arizona, Tucson, AZ, USA.

Roos CI, Swetnam TW (2012) A 1416-year reconstruction of annual, multidecadal, and centennial variability in area burned for ponderosa pine forests of the southern Colorado Plateau region, southwest USA. The Holocene 22, 281–290.
A 1416-year reconstruction of annual, multidecadal, and centennial variability in area burned for ponderosa pine forests of the southern Colorado Plateau region, southwest USA.Crossref | GoogleScholarGoogle Scholar |

Routson CC, Woodhouse CA, Overpeck JT (2011) Second century megadrought in the Rio Grande headwaters, Colorado: how unusual was medieval drought? Geophysical Research Letters 38, L22703
Second century megadrought in the Rio Grande headwaters, Colorado: how unusual was medieval drought?Crossref | GoogleScholarGoogle Scholar |

Salzer MW, Kipfmueller KF (2005) Reconstructed temperature and precipitation on a millennial timescale from tree-rings in the southern Colorado Plateau, USA. Climatic Change 70, 465–487.
Reconstructed temperature and precipitation on a millennial timescale from tree-rings in the southern Colorado Plateau, USA.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2MXntFSht7g%3D&md5=d6dd424fa401911c1d222bc0c12fb995CAS |

Seager R, Ting M, Held I, Kushnir Y, Lu J, Vecchi G, Huang H-P, Harnik N, Leetmaa A, Lau N-C, Li C, Velez J, Naik N (2007) Model projections of an imminent transition to a more arid climate in southwestern North America. Science 316, 1181–1184.
Model projections of an imminent transition to a more arid climate in southwestern North America.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXls1Kisb8%3D&md5=971457feedd277a7eae4da5c84da599fCAS |

Shakesby RA, Doerr SH (2006) Wildfire as a hydrological and geomorphological agent. Earth-Science Reviews 74, 269–307.
Wildfire as a hydrological and geomorphological agent.Crossref | GoogleScholarGoogle Scholar |

Stephens SL, McIver JD, Boerner REJ, Fettig CJ, Fontaine JW, Hartsough BR, Kennedy PL, Schwilk DW (2012) The effects of forest fuel-reduction treatments in the United States. Bioscience 62, 549–560.
The effects of forest fuel-reduction treatments in the United States.Crossref | GoogleScholarGoogle Scholar |

Stephens SL, Agee JK, Fulé PZ, North MP, Romme WH, Swetnam TW, Turner MG (2013) Managing forests and fire in changing climates. Science 342, 41–42.
Managing forests and fire in changing climates.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3sXhsF2jtrjE&md5=34a9385dca0a2639f3ad0406c53b7764CAS |

Stine S (1994) Extreme and persistent drought in California and Patagonia during mediaeval time. Nature 369, 546–549.
Extreme and persistent drought in California and Patagonia during mediaeval time.Crossref | GoogleScholarGoogle Scholar |

Stuiver M, Reimer PJ (1993) Extended 14C data base and revised Calib 3.0 14C age calibration program. Radiocarbon 35, 215–230.
Extended 14C data base and revised Calib 3.0 14C age calibration program.Crossref | GoogleScholarGoogle Scholar |

Swetnam TW, Baisan CH (1996) Historical fire regime patterns in the southwestern United States since AD 1700. In ‘Fire Effects in Southwestern Forests: Proceedings of the Second La Mesa Fire Symposium’ (Ed. CD Allen) USDA Forest Service, General Technical Report RM-GTR-286, pp. 11–32. (Fort Collins, CO, USA)

Swetnam TW, Baisan CH (2003) Tree-ring reconstructions of fire and climate history in the Sierra Nevada and southwestern United States. In ‘Fire and Climatic Change in Temperate Ecosystems of the Western Americas’. (Eds TT Veblen, WL Baker, G Montenegro, TW Swetnam) pp. 154–192. (Springer-Verlag: New York, NY, USA)

Swetnam TW, Betancourt JL (1990) Fire-southern oscillation relations in the southwestern United States. Science 249, 1017–1020.
Fire-southern oscillation relations in the southwestern United States.Crossref | GoogleScholarGoogle Scholar | 1:STN:280:DC%2BC3cvjt1ygsQ%3D%3D&md5=ffce871ebbce7d83235f25fc5720cf95CAS |

Swetnam TW, Betancourt JL (1998) Mesoscale disturbance and ecological response to decadal climatic variability in the American southwest. Journal of Climate 11, 3128–3147.
Mesoscale disturbance and ecological response to decadal climatic variability in the American southwest.Crossref | GoogleScholarGoogle Scholar |

Swetnam TW, Baisan CH, Caprio AC, Brown PM, Touchan R, Anderson RS, Hallett DJ (2009) Multi-millennial fire history of the Giant Forest, Sequoia National Park, California, USA. Fire Ecology 5, 120–150.
Multi-millennial fire history of the Giant Forest, Sequoia National Park, California, USA.Crossref | GoogleScholarGoogle Scholar |

Telford RJ, Heegaard E, Birks HJB (2004) The intercept is a poor estimate of a calibrated radiocarbon age. The Holocene 14, 296–298.
The intercept is a poor estimate of a calibrated radiocarbon age.Crossref | GoogleScholarGoogle Scholar |

Toney JL, Anderson RS (2006) A postglacial palaeoecological record from the San Juan Mountains of Colorado US : fire, climate and vegetation history. The Holocene 16, 505–517.
A postglacial palaeoecological record from the San Juan Mountains of Colorado US : fire, climate and vegetation history.Crossref | GoogleScholarGoogle Scholar |

Trouet V, Diaz HF, Wahl ER, Viau AE, Graham R, Graham N, Cook ER (2013) A 1500-year reconstruction of annual mean temperature for temperate North America on decadal-to-multidecadal time scales. Environmental Research Letters 8, 024008
A 1500-year reconstruction of annual mean temperature for temperate North America on decadal-to-multidecadal time scales.Crossref | GoogleScholarGoogle Scholar |

Weppner KN, Pierce JL, Betancourt JL (2013) Holocene fire occurrence and alluvial responses at the leading edge of pinyon–juniper migration in the Northern Great Basin, USA. Quaternary Research 80, 143–157.
Holocene fire occurrence and alluvial responses at the leading edge of pinyon–juniper migration in the Northern Great Basin, USA.Crossref | GoogleScholarGoogle Scholar |

Westerling AL (2016) Increasing western US forest wildfire activity: sensitivity to changes in the timing of Spring. Philosophical Transactions of the Royal Society B: Biological Sciences 371, 20150178
Increasing western US forest wildfire activity: sensitivity to changes in the timing of Spring.Crossref | GoogleScholarGoogle Scholar |

Westerling AL, Hidalgo HG, Cayan DR, Swetnam TW (2006) Warming and earlier spring increase western US forest wildfire activity. Science 313, 940–943.
Warming and earlier spring increase western US forest wildfire activity.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD28XotFCitbo%3D&md5=cbcea74aa07cca2474f3f7a57e8a12acCAS |

Whitlock CW, Anderson RS (2003) Fire history reconstructions based on sediment records from lakes and wetlands. ‘Fire and Climatic Change in Temperate Ecosystems of the Western Americas’. (Eds TT Veblen, WL Baker, G Montenegro, TW Swetnam) pp. 3–31. (Springer-Verlag: New York, NY< USA)

Williams AP, Allen CD, Millar CI, Swetnam TW, Michaelsen J, Still CJ, Leavitt SW (2010) Forest responses to increasing aridity and warmth in the southwestern United States. Proceedings of the National Academy of Sciences of the United States of America 107, 21289–21294.
Forest responses to increasing aridity and warmth in the southwestern United States.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXhs1Wis7bN&md5=11e4913f742aaab7e7172ddc09c221deCAS |

Wise EK (2016) Five centuries of US west coast drought: occurrence, spatial distribution, and associated atmospheric circulation patterns. Geophysical Research Letters 43, 4539–4546.
Five centuries of US west coast drought: occurrence, spatial distribution, and associated atmospheric circulation patterns.Crossref | GoogleScholarGoogle Scholar |

Woodhouse CA, Kunkel KE, Easterling DR, Cook ER (2005) The twentieth-century pluvial in the western United States. Geophysical Research Letters 32, 11–14.
The twentieth-century pluvial in the western United States.Crossref | GoogleScholarGoogle Scholar |

Woodhouse CA, Meko DM, MacDonald GM, Stahle DW, Cook ER (2010) A 1200-year perspective of 21st century drought in southwestern North America. Proceedings of the National Academy of Sciences of the United States of America 107, 21283–21288.
A 1200-year perspective of 21st century drought in southwestern North America.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXhs1Wis7bM&md5=5637dd3b0f6cfc6fa34134400a8d3d9cCAS |