TY - JOUR
T1 - Late-holocene relationships among fire,climate and vegetation in a forest-sagebrush ecotone of southwestern idaho,USA
AU - Nelson, Nathan A.
AU - Pierce, Jennifer
PY - 2010/12
Y1 - 2010/12
N2 - The forest-sagebrush ecotone is characterized by a more arid climate than forested regions; therefore, establishing fire histories using traditional methods (e.g. fire-scars from trees, charcoal in lake sediments) is problematic. This study uses radiocarbon dating of charcoal preserved in alluvial deposits to reconstruct a record of fire and geomorphic response in southwestern Idaho. Samples indicate three primary periods of fire-related activity: 4400-4000, 2000-1400, and 650-400 cal. yr BP. Charcoal macrofossil identification and comparison with other regional records indicate this area has likely alternated between a 'fuel-limited' system (fires limited by lack of fuels), and a 'moisture-limited' system (fires limited by too much moisture) with changes in Holocene climate. Over the past ~2000 yr, samples from this site indicate most fires occurred during wetter times than the record average. During overall wetter periods, (e.g. 'Little Ice Age' (LIA); 600-100 cal. yr BP) tree density may have increased, and fires occurred during intervals of relative drought. During times of prolonged drought (e.g. 'Medieval Climate Anomaly' (MCA); 1025-650 cal. yr BP) fire was recorded during a wetter interval. After ~600 cal. yr BP, fire activity was similar to alluvial charcoal records of low-intensity fires in a nearby ponderosa pine-dominated drainage, and sagebrush is common in charcoal samples. Both the ponderosa site and the Wood Creek site show low fire activity in ~6500-5000 cal yr BP; climatically, ~7-5 ka appears to correspond with regional records of drought. This work provides a unique record of fire in a semi-arid ecotone where (1) few records exist because of the paucity of dating sites, and (2) climatic sensitivity is likely enhanced.
AB - The forest-sagebrush ecotone is characterized by a more arid climate than forested regions; therefore, establishing fire histories using traditional methods (e.g. fire-scars from trees, charcoal in lake sediments) is problematic. This study uses radiocarbon dating of charcoal preserved in alluvial deposits to reconstruct a record of fire and geomorphic response in southwestern Idaho. Samples indicate three primary periods of fire-related activity: 4400-4000, 2000-1400, and 650-400 cal. yr BP. Charcoal macrofossil identification and comparison with other regional records indicate this area has likely alternated between a 'fuel-limited' system (fires limited by lack of fuels), and a 'moisture-limited' system (fires limited by too much moisture) with changes in Holocene climate. Over the past ~2000 yr, samples from this site indicate most fires occurred during wetter times than the record average. During overall wetter periods, (e.g. 'Little Ice Age' (LIA); 600-100 cal. yr BP) tree density may have increased, and fires occurred during intervals of relative drought. During times of prolonged drought (e.g. 'Medieval Climate Anomaly' (MCA); 1025-650 cal. yr BP) fire was recorded during a wetter interval. After ~600 cal. yr BP, fire activity was similar to alluvial charcoal records of low-intensity fires in a nearby ponderosa pine-dominated drainage, and sagebrush is common in charcoal samples. Both the ponderosa site and the Wood Creek site show low fire activity in ~6500-5000 cal yr BP; climatically, ~7-5 ka appears to correspond with regional records of drought. This work provides a unique record of fire in a semi-arid ecotone where (1) few records exist because of the paucity of dating sites, and (2) climatic sensitivity is likely enhanced.
KW - fire history
KW - fuel limited
KW - geomorphology
KW - Holocene
KW - Idaho
KW - moisture limited
KW - sagebrush-forest ecotone
KW - sedimentary charcoal
UR - http://www.scopus.com/inward/record.url?scp=78649428535&partnerID=8YFLogxK
U2 - 10.1177/0959683610371992
DO - 10.1177/0959683610371992
M3 - Article
AN - SCOPUS:78649428535
SN - 0959-6836
VL - 20
SP - 1179
EP - 1194
JO - Holocene
JF - Holocene
IS - 8
ER -