Special Issue: Fire History in California
Author: Thomas W. Swetnam
Pages: 1-3
DOI: 10.4996/fireecology.0503001
A common refrain that fire historians hear from managers and scientists is: “Haven’t we done enough fire history studies already, especially in ponderosa pine? What more is there to learn?” It is true that there are dozens of published studies in western North America using tree rings to evaluate the historical range and variability of past fire regimes. It is also true that the majority of these studies were conducted in pine dominant or mixed-conifer forests where moderate to high frequency surface fire regimes prevailed for centuries before the fire suppression era.
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Fire History of a Lower Elevation Jeffrey Pine-Mixed Conifer Forest in the Eastern Sierra Nevada, California, USA
Author: Nicole M. Vaillant and Scott L. Stephens
Pages: 4-19
DOI: 10.4996/fireecology.0503004
For thousands of years, fire has shaped coniferous forests of the western United States. In more recent time, land use practices have altered the role fire plays in the Sierra Nevada. By understanding the past, land managers can design better fuel treatments today. This research explores the fire regimes of Sagehen Experimental Forest in the eastern Sierra Nevada, California, through a fire scar reconstruction of lower elevation Jeffrey pine (Pinus jeffreyi Balf.) and Jeffrey pine-mixed conifer stands. Read More.
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Climate, Rain Shadow, and Human-Use Influences on Fire Regimes in the Eastern Sierra Nevada, California, USA
Author: Malcolm P. North, Kip M. Van de Water, Scott L. Stephens, and Brandon M. Collins
Pages: 20-34
DOI: 10.4996/fireecology.0503020
There have been few fire history studies of eastern Sierra Nevada forests in California, USA, where a steep elevation gradient, rain shadow conditions, and forest stand isolation may produce different fire regimes than those found on the range’s western slope. We investigated historic fire regimes and potential climate influences on four forest types ranging in elevation from 1700 m to 3200 m on the Sierra Nevada’s eastern slope and the White Mountains’ western slope. Sample areas (approximately 15 ha to 45 ha) had mean site fire return intervals ranging from 4.8 yr to 16.9 yr across ten Jeffrey pine (Pinus jeffreyi Balf.) sites, and 13.4 yr to 45.7 yr across four high elevation lodgepole (P. contorta Douglas ex Louden), foxtail (P. balfouriana Balf.) and bristlecone (P. longaeva D.K. Bailey) pine sites. Read More.
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Using Bigcone Douglas-Fir Fire Scars and Tree Rings to Reconstruct Interior Chaparral Fire History
Author: Keith J. Lombardo, Thomas W. Swetnam, Christopher H. Baisan, Mark I. Borchert
Pages: 35-56
DOI: 10.4996/fireecology.0503035
Bigcone Douglas-fir (Pseudotsuga macrocarpa [Vasey] Mayr) is a long-lived, fire-adapted conifer that is endemic to the Transverse Ranges of southern California. At the lower and middle reaches of its elevational distribution, isolated stands of bigcone Douglas-fir are surrounded by extensive stands of chaparral. Our dendrochronology investigations have revealed that these ancient trees commonly record multiple past fires as fire scars in their lower boles. We hypothesized that the fire-scar record found within and among bigcone Douglas-fir stands reflects the temporal and spatial patterns of fire in the surrounding chaparral. Read More.
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Top-Down and Bottom-Up Controls on Fire Regimes along an Elevational Gradient on the East Slope of the Sierra Nevada, California, USA
Author: Lisa Gill and Alan H. Taylor
Pages: 57-75
DOI: 10.4996/fireecology.0503057
Fire is an ecologically significant process in the fire-prone ponderosa pine and mixed conifer forests of the northern Sierra Nevada. Fire regimes are influenced by processes that operate over a range of scales that can be grouped broadly as bottom-up (e.g., topography, forest type) or top-down (e.g., climate variation, human land use) controls. To identify the bottom-up versus top-down controls on fire regimes, we quantified spatial and temporal variation in fire occurrence and extent using fire-scar dendrochronology. Inter-annual climate variability and human land use patterns strongly influenced fire regimes. Read More.
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Human and Climatic Influences on Fire Occurrence in California’s North Coast Range, USA
Author: Carl N. Skinner, Celeste S. Abbott, Danny L. Fry, Scott L. Stephens, Alan H. Taylor, Valerie Trouet
Pages: 76-99
DOI: 10.4996/fireecology.0503076
Outside of the immediate coastal environments, little is known of fire history in the North Coast Range of California. Fire scar specimens were collected from ponderosa pine (Pinus ponderosa C. Lawson), sugar pine (Pinus lambertiana Douglas), incense cedar (Calocedrus decurrens [Torr] Florin), and Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) for seven plots in mixed-conifer forests from the Mendocino National Forest, California, USA. Five plots were on high ridges immediately adjacent to the Sacramento Valley (DRY plots). The other two plots were on mesic north facing slopes interior in the range (MESIC plots), and were separated from the Sacramento Valley by at least one to several ridge systems. These two plots were selected because they supported populations of rare lady’s slipper orchids (Cypripedium fasciculatum [Kellogg ex S. Watson] and C. montanum [Douglas ex Lindl.]). Read More.
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Fire History, Stand Origins, and the Persistence of McNab Cypress, Northern California, USA
Author: Chris R. Mallek
Pages: 100-119
DOI: 10.4996/fireecology.0503100
Despite their substantial contribution to the uniqueness and diversity of the California Floristic Province’s flora and vegetation, surprisingly little is known about the region’s native cypress species (genus Hesperocyparis Bartel & R.A. Price). Current ideas about the fire regimes that maintained these species in the past are based largely or solely on assumptions about the expression and function of life-history characteristics. Empirical studies of fire history are generally lacking. I used a combination of dendrochronological methods, field observations, and contemporary fire records to investigate the history of fire and its role in stand development in McNab cypress (Hesperocyparis macnabiana [A. Murray bis] Bartel), an uncommon serotinous cypress endemic to northern California. Read More.
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Multi-Millennial Fire History of the Giant Forest, Sequoia National Park, California, USA
Author: Thomas W. Swetnam, Christopher H. Baisan, Anthony C. Caprio, Peter M. Brown, Ramzi Touchan, R. Scott Anderson, and Douglas J. Hallett
Pages: 120-150
DOI: 10.4996/fireecology.0503120
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 increasing 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 widespread 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. Read More.
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