TY - JOUR
T1 - Multi-millennial fire history of the giant forest, Sequoia National Park, California, USA
AU - Swetnam, Thomas W.
AU - Baisan, Christopher H.
AU - Caprio, Anthony C.
AU - Brown, Peter M.
AU - Touchan, Ramzi
AU - Scott Anderson, R.
AU - Hallett, Douglas J.
N1 - Funding Information:
We thank the many people who helped and contributed to our giant sequoia fire history work over the past 20 years, especially: Dave Dulitz, Wayne Harrison, Malcolm Hughes, Linda Mutch, Dave Parsons, Bill Peachy, Nate Stephenson, Susan Smith, Jan van Wagtendonk, and many others. Funding and logistics support were provided by the National Park Service, US Geological Survey’s Global Change Research Program and Western Mountain Initiative, Mountain Home Demonstration State Forest, Calaveras Big Trees State Park, the University of Arizona, and Northern Arizona University. We also thank Nate Stephenson and an anonymous reviewer for their thoughtful review comments and editing of the manuscript.
Funding Information:
Our studies, funded by the National Park Service (and later the US Geological Survey Global Change Research Program and the California State Parks) were aimed specifically at sampling stumps of giant sequoias remaining from logging enterprises of the late nineteenth and early twentieth centuries. It is estimated that roughly one fourth of all giant sequoia trees were felled, including most of the big trees in the huge Converse Basin grove about 30 km north of the Giant Forest. Protecting some of the remaining sequoia groves, including the Giant Forest, was a primary stimulus for the establishment of Sequoia and Kings Canyon national parks (Dilsaver and Tweed ).
PY - 2009
Y1 - 2009
N2 - Giant sequoias (Sequoiadendron giganteum [Lindl.] J. Buchholz) preserve a detailed history of fire within their annual rings. We developed a 3000 year chronology of fire events in one of the largest extant groves of ancient giant sequoias, the Giant Forest, by sampling and tree-ring dating fire scars and other fire-related indicators from 52 trees distributed over an area of about 350 ha. When all fire events were included in composite chronologies, the mean fire intervals (years between fires of any size) declined as a function of in-creasing spatial extent from tree, to group, to multiple groups, to grove scales: 15.5 yr (0.1 ha), 7.4 yr (1 ha.), 3.0 yr (70 ha), and 2.2 yr (350 ha), respectively. We interpreted wide-spread fires (i.e., fire events recorded on ≥2 trees, or ≥25% of all trees recording fires within composites) to have occurred in areas of 70 ha to 350 ha at mean intervals ranging from about 6 yr to 35 yr. We compared the annual, multi-decadal and centennial variations in Giant Forest fire frequency with those documented in tree-ring and charcoal-based fire chronologies from four other giant sequoia groves in the Sierra Nevada, and with independent tree-ring-based reconstructions of summer drought and temperatures. The other giant sequoia fire histories (tree rings and charcoal-based) were significantly (P < 0.001) correlated with the Giant Forest fire frequency record and independent climate reconstructions, and confirm a maximum fire frequency during the warm and drought-prone period from 800 C.E. to 1300 C.E. (Common Era). This was the driest period of the past two millennia, and it may serve as an analog for warming and drying effects of anthropogenic greenhouse gases in the next few decades. Sequoias can sustain very high fire frequencies, and historically they have done so during warm, dry times. We suggest that preparation of sequoia groves for anticipated warming may call for increasing the rate of prescribed burning in most parts of the Giant Forest.
AB - Giant sequoias (Sequoiadendron giganteum [Lindl.] J. Buchholz) preserve a detailed history of fire within their annual rings. We developed a 3000 year chronology of fire events in one of the largest extant groves of ancient giant sequoias, the Giant Forest, by sampling and tree-ring dating fire scars and other fire-related indicators from 52 trees distributed over an area of about 350 ha. When all fire events were included in composite chronologies, the mean fire intervals (years between fires of any size) declined as a function of in-creasing spatial extent from tree, to group, to multiple groups, to grove scales: 15.5 yr (0.1 ha), 7.4 yr (1 ha.), 3.0 yr (70 ha), and 2.2 yr (350 ha), respectively. We interpreted wide-spread fires (i.e., fire events recorded on ≥2 trees, or ≥25% of all trees recording fires within composites) to have occurred in areas of 70 ha to 350 ha at mean intervals ranging from about 6 yr to 35 yr. We compared the annual, multi-decadal and centennial variations in Giant Forest fire frequency with those documented in tree-ring and charcoal-based fire chronologies from four other giant sequoia groves in the Sierra Nevada, and with independent tree-ring-based reconstructions of summer drought and temperatures. The other giant sequoia fire histories (tree rings and charcoal-based) were significantly (P < 0.001) correlated with the Giant Forest fire frequency record and independent climate reconstructions, and confirm a maximum fire frequency during the warm and drought-prone period from 800 C.E. to 1300 C.E. (Common Era). This was the driest period of the past two millennia, and it may serve as an analog for warming and drying effects of anthropogenic greenhouse gases in the next few decades. Sequoias can sustain very high fire frequencies, and historically they have done so during warm, dry times. We suggest that preparation of sequoia groves for anticipated warming may call for increasing the rate of prescribed burning in most parts of the Giant Forest.
KW - Dendrochronology
KW - Fire history
KW - Giant forest
KW - Giant sequoia
KW - Sequoia national park
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U2 - 10.4996/fireecology.0503120
DO - 10.4996/fireecology.0503120
M3 - Article
AN - SCOPUS:77949645934
SN - 1933-9747
VL - 5
SP - 120
EP - 150
JO - Fire Ecology
JF - Fire Ecology
IS - 3
ER -