A 7600 yr vegetation and fire history from Anthony Lake, northeastern Oregon, USA, with linkages to modern synoptic climate patterns

2019 ◽  
Vol 91 (2) ◽  
pp. 705-713
Author(s):  
Colin J. Long ◽  
Jaqueline J. Shinker ◽  
Thomas A. Minckley ◽  
Mitchell J. Power ◽  
Patrick J. Bartlein
Keyword(s):  
High Resolution ◽  
Great Basin ◽  
Fire History ◽  
Fire Occurrence ◽  
Charcoal Analysis ◽  
Dry Air ◽  
Blue Mountains ◽  
Climate Patterns ◽  
Dry Conditions ◽  
In Fire

AbstractWe used pollen and high-resolution charcoal analysis of lake sediment to reconstruct a 7600 yr vegetation and fire history from Anthony Lake, located in the Blue Mountains of northeastern Oregon. From 7300 to 6300 cal yr BP, the forest was composed primarily of Populus, and fire was common, indicating warm, dry conditions. From 6300 to 3000 cal yr BP, Populus declined as Pinus and Picea increased in abundance and fire became less frequent, suggesting a shift to cooler, wetter conditions. From 3000 cal yr BP to present, modern-day forests composed of Pinus and Abies developed, and from 1650 cal yr BP to present, fires increased. We utilized the modern climate-analogue approach to explain the potential synoptic climatological processes associated with regional fire. The results indicate that years with high fire occurrence experience positive 500 mb height anomalies centered over the Great Basin, with anomalous southerly component of flow delivering dry air into the region and with associated sinking motions to further suppress precipitation. It is possible that such conditions became more common over the last 1650 cal yr BP, supporting an increase in fire despite the shift to more mesic conditions.

Variability in fire - climate relationships in ponderosa pine forests in the Colorado Front Range

2008 ◽  
Vol 17 (1) ◽  
pp. 50 ◽  
Author(s):  
Rosemary L. Sherriff ◽  
Thomas T. Veblen
Keyword(s):  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Fire History ◽  
Southern Oscillation ◽  
Primary Objective ◽  
Fire Occurrence ◽  
Ponderosa Pine Forests ◽  
Fire Scar ◽  
Montane Zone ◽  
In Fire

Understanding the interactions of climate variability and wildfire has been a primary objective of recent fire history research. The present study examines the influence of El Niño–Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO) and Atlantic Multidecadal Oscillation (AMO) on fire occurrence using fire-scar evidence from 58 sites from the lower ecotone to the upper elevational limits of ponderosa pine (Pinus ponderosa) in northern Colorado. An important finding is that at low v. high elevations within the montane zone, climatic patterns conducive to years of widespread fire are different. Differences in fire–climate relationships are manifested primarily in antecedent year climate. Below ~2100 m, fires are dependent on antecedent moister conditions that favour fine fuel accumulation 2 years before dry fire years. In the upper montane zone, fires are dependent primarily on drought rather than an increase in fine fuels. Throughout the montane zone, fire is strongly linked to variations in moisture availability that in turn is linked to climate influences of ENSO, PDO and AMO. Fire occurrence is greater than expected during the phases of each index associated with drought. Regionally widespread fire years are associated with specific phase combinations of ENSO, PDO and AMO. In particular, the combination of La Niña, negative PDO and positive AMO is highly conducive to widespread fire.

scholarly journals Reconstructing fire history in central Mongolia from tree-rings

2012 ◽  
Vol 21 (1) ◽  
pp. 86 ◽  
Author(s):  
Amy E. Hessl ◽  
Uyanga Ariya ◽  
Peter Brown ◽  
Oyunsannaa Byambasuren ◽  
Tim Green ◽  
...  
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Cross Sections ◽  
Fire History ◽  
Test Case ◽  
Fire Occurrence ◽  
Central Mongolia ◽  
Targeted Sampling ◽  
In Fire ◽  
Use Factors

Rising temperatures are expected to increase wildfire activity in many regions of the world. Over the last 60 years in Mongolia, mean annual temperatures have increased ~2°C and the recorded frequency and spatial extent of forest and steppe fires have increased. Few long records of fire history exist to place these recent changes in a historical perspective. The purpose of this paper is to report on fire history research from three sites in central Mongolia and to highlight the potential of this region as a test case for understanding the relationships between climate change, fire and land use. We collected partial cross-sections from fire-scarred trees and stumps at each site using a targeted sampling approach. All three sites had long histories of fire ranging from 280 to 450 years. Mean Weibull fire return intervals varied from 7 to 16 years. Fire scars at one protected-area site were nearly absent after 1760, likely owing to changes in land use. There is limited synchrony in fire occurrence across sites, suggesting that fire occurrence, at least at annual time scales, might be influenced by local processes (grazing, human ignitions, other land-use factors) as well as regional processes like climate. Additional data are being collected to further test hypotheses regarding climate change, land use and fire.

scholarly journals Hydrological dynamics and fire history of the last 1300 years in western Siberia reconstructed from a high-resolution, ombrotrophic peat archive

2015 ◽  
Vol 84 (3) ◽  
pp. 312-325 ◽  
Author(s):  
Mariusz Lamentowicz ◽  
Michał Słowiński ◽  
Katarzyna Marcisz ◽  
Małgorzata Zielińska ◽  
Karolina Kaliszan ◽  
...  
Keyword(s):  
Fire History ◽  
Western Siberia ◽  
Plant Macrofossils ◽  
Testate Amoebae ◽  
Carbon Accumulation ◽  
Ice Age ◽  
Fire Activity ◽  
Dry Conditions ◽  
History Of ◽  
In Fire

Siberian peatlands provide records of past changes in the continental climate of Eurasia. We analyzed a core from Mukhrino mire in western Siberia to reconstruct environmental change in this region over the last 1300 years. The pollen analysis revealed little variation of local pine-birch forests. A testate amoebae transfer function was used to generate a quantitative water-table reconstruction; pollen, plant macrofossils, and charcoal were analyzed to reconstruct changes in vegetation and fire activity. The study revealed that Mukhrino mire was wet until the Little Ice Age (LIA), when drought was recorded. Dry conditions during the LIA are consistent with other studies from central and eastern Europe, and with the pattern of carbon accumulation across the Northern Hemisphere. A significant increase in fire activity between ca. AD 1975 and 1990 may be associated with the development of the nearby city of Khanty-Mansiysk, as well as with the prevailing positive Arctic Oscillation.

A lake sediment–based paleoecological reconstruction of late Holocene fire history and vegetation change in Great Basin National Park, Nevada, USA

2021 ◽  
pp. 1-15
Author(s):  
Christopher S. Cooper ◽  
David F. Porinchu ◽  
Scott A. Reinemann ◽  
Bryan G. Mark ◽  
James Q. DeGrand
Keyword(s):  
Great Basin ◽  
Relative Abundance ◽  
Vegetation Change ◽  
Fire History ◽  
Ice Age ◽  
Sediment Geochemistry ◽  
Catchment Scale ◽  
Composition And Structure ◽  
Hydroclimate Variability ◽  
Late Fifteenth

Abstract Analyses of macroscopic charcoal, sediment geochemistry (%C, %N, C/N, δ13C, δ15N), and fossil pollen were conducted on a sediment core recovered from Stella Lake, Nevada, establishing a 2000 year record of fire history and vegetation change for the Great Basin. Charcoal accumulation rates (CHAR) indicate that fire activity, which was minimal from the beginning of the first millennium to AD 750, increased slightly at the onset of the Medieval Climate Anomaly (MCA). Observed changes in catchment vegetation were driven by hydroclimate variability during the early MCA. Two notable increases in CHAR, which occurred during the Little Ice Age (LIA), were identified as major fire events within the catchment. Increased C/N, enriched δ15N, and depleted δ13C values correspond with these events, providing additional evidence for the occurrence of catchment-scale fire events during the late fifteenth and late sixteenth centuries. Shifts in the vegetation community composition and structure accompanied these fires, with Pinus and Picea decreasing in relative abundance and Poaceae increasing in relative abundance following the fire events. During the LIA, the vegetation change and lacustrine geochemical response was most directly influenced by the occurrence of catchment-scale fires, not regional hydroclimate.

Fire regime shift linked to increased forest density in a piñon–juniper savanna landscape

2014 ◽  
Vol 23 (2) ◽  
pp. 234 ◽  
Author(s):  
Ellis Q. Margolis
Keyword(s):  
Regime Shift ◽  
Fire History ◽  
Fire Regime ◽  
Fire Regimes ◽  
Fire Frequency ◽  
Climatic Conditions ◽  
Tree Density ◽  
High Severity ◽  
Wide Range ◽  
In Fire

Piñon–juniper (PJ) fire regimes are generally characterised as infrequent high-severity. However, PJ ecosystems vary across a large geographic and bio-climatic range and little is known about one of the principal PJ functional types, PJ savannas. It is logical that (1) grass in PJ savannas could support frequent, low-severity fire and (2) exclusion of frequent fire could explain increased tree density in PJ savannas. To assess these hypotheses I used dendroecological methods to reconstruct fire history and forest structure in a PJ-dominated savanna. Evidence of high-severity fire was not observed. From 112 fire-scarred trees I reconstructed 87 fire years (1547–1899). Mean fire interval was 7.8 years for fires recorded at ≥2 sites. Tree establishment was negatively correlated with fire frequency (r=–0.74) and peak PJ establishment was synchronous with dry (unfavourable) conditions and a regime shift (decline) in fire frequency in the late 1800s. The collapse of the grass-fuelled, frequent, surface fire regime in this PJ savanna was likely the primary driver of current high tree density (mean=881treesha–1) that is >600% of the historical estimate. Variability in bio-climatic conditions likely drive variability in fire regimes across the wide range of PJ ecosystems.

Holocene Climatic Variations Inferred from Treeline Fluctuations in the White Mountains, California

1973 ◽  
Vol 3 (4) ◽  
pp. 632-660 ◽  
Author(s):  
Valmore C. LaMarche
Keyword(s):  
Great Basin ◽  
Warm Season ◽  
White Mountains ◽  
North American Cordillera ◽  
Climatic Variations ◽  
The Past ◽  
The North ◽  
Pinus Longaeva ◽  
Bristlecone Pine ◽  
Dry Conditions

AbstractRemains of dead bristlecone pine (Pinus longaeva Bailey) are found at altitudes up to 150 m above present treeline in the White Mountains. Standing snags and remnants in two study areas were mapped and sampled for dating by tree-ring and radiocarbon methods. The oldest remnants represent trees established more than 7400 y.a. Experimental and empirical evidence indicates that the position of the treeline is closely related to warm-season temperatures, but that precipitation may also be important in at least one of the areas. The upper treeline was at high levels in both areas until after about 2200 B.C., indicating warm-season temperatures about 3.5°F higher than those of the past few hundred years. However, the record is incomplete, relative warmth may have been maintained until at least 1500 B.C. Cooler and wetter conditions are indicated for the period 1500 B.C.-500 B.C., followed by a period of cool but drier climate. A major treeline decline occurred between about A.D. 1100 and A.D. 1500, probably reflecting onset of cold and dry conditions. High reproduction rates and establishment of scattered seedlings at high altitudes within the past 100 yr represents an incipient treeline advance, which reflected a general climatic warming beginning in the mid-19th century that has lasted until recent decades in the western United States. This evidence for climatic variation is broadly consistent with the record of Neoglacial advances in the North American Cordillera, and supports Antevs' concept of a warm “altithermal age” in the Great Basin.

Current and future patterns of forest fire occurrence in China

2020 ◽  
Vol 29 (2) ◽  
pp. 104 ◽  
Author(s):  
Zhiwei Wu ◽  
Hong S. He ◽  
Robert E. Keane ◽  
Zhiliang Zhu ◽  
Yeqiao Wang ◽  
...  
Keyword(s):  
Forest Fire ◽  
General Circulation ◽  
Southern China ◽  
Northern China ◽  
General Circulation Models ◽  
Boosted Regression Trees ◽  
Fire Occurrence ◽  
Representative Concentration Pathways ◽  
Fire Patterns ◽  
In Fire

Forest fire patterns are likely to be altered by climate change. We used boosted regression trees modelling and the MODIS Global Fire Atlas dataset (2003–15) to characterise relative influences of nine natural and human variables on fire patterns across five forest zones in China. The same modelling approach was used to project fire patterns for 2041–60 and 2061–80 based on two general circulation models for two representative concentration pathways scenarios. The results showed that, for the baseline period (2003–15) and across the five forest zones, climate variables explained 37.4–43.5% of the variability in fire occurrence and human activities were responsible for explaining an additional 27.0–36.5% of variability. The fire frequency was highest in the subtropical evergreen broadleaf forests zone in southern China, and lowest in the warm temperate deciduous broadleaved mixed-forests zone in northern China. Projection results showed an increasing trend in fire occurrence probability ranging from 43.3 to 99.9% and 41.4 to 99.3% across forest zones under the two climate models and two representative concentration pathways scenarios relative to the current climate (2003–15). Increased fire occurrence is projected to shift from southern to central-northern China for both 2041–60 and 2061–80.

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