scholarly journals Rocky Mountain subalpine forests now burning more than any time in recent millennia

2021 ◽  
Vol 118 (25) ◽  
pp. e2103135118
Author(s):  
Philip E. Higuera ◽  
Bryan N. Shuman ◽  
Kyra D. Wolf
Keyword(s):  
21St Century ◽  
Fire History ◽  
Average Rate ◽  
Rotation Period ◽  
Rocky Mountain ◽  
Fire Season ◽  
Subalpine Forests ◽  
The Past ◽  
Fire Activity ◽  
Central Rocky Mountains

The 2020 fire season punctuated a decades-long trend of increased fire activity across the western United States, nearly doubling the total area burned in the central Rocky Mountains since 1984. Understanding the causes and implications of such extreme fire seasons, particularly in subalpine forests that have historically burned infrequently, requires a long-term perspective not afforded by observational records. We place 21st century fire activity in subalpine forests in the context of climate and fire history spanning the past 2,000 y using a unique network of 20 paleofire records. Largely because of extensive burning in 2020, the 21st century fire rotation period is now 117 y, reflecting nearly double the average rate of burning over the past 2,000 y. More strikingly, contemporary rates of burning are now 22% higher than the maximum rate reconstructed over the past two millennia, during the early Medieval Climate Anomaly (MCA) (770 to 870 Common Era), when Northern Hemisphere temperatures were ∼0.3 °C above the 20th century average. The 2020 fire season thus exemplifies how extreme events are demarcating newly emerging fire regimes as climate warms. With 21st century temperatures now surpassing those during the MCA, fire activity in Rocky Mountain subalpine forests is exceeding the range of variability that shaped these ecosystems for millennia.

scholarly journals Fire in ice: two millennia of Northern Hemisphere fire history from the Greenland NEEM ice core

2014 ◽  
Vol 10 (1) ◽  
pp. 809-857 ◽  
Author(s):  
P. Zennaro ◽  
N. Kehrwald ◽  
J. R. McConnell ◽  
S. Schüpbach ◽  
O. Maselli ◽  
...  
Keyword(s):  
Black Carbon ◽  
Biomass Burning ◽  
Fire History ◽  
Global Climate ◽  
Ice Cores ◽  
Dominant Factor ◽  
The Past ◽  
Past 2000 Years ◽  
Isotopic Analyses ◽  
Fire Activity

Abstract. Biomass burning is a major source of greenhouse gases and influences regional to global climate. Pre-industrial fire-history records from black carbon, charcoal and other proxies provide baseline estimates of biomass burning at local to global scales, but there remains a need for broad-scale fire proxies that span millennia in order to understand the role of fire in the carbon cycle and climate system. We use the specific biomarker levoglucosan, and multi-source black carbon and ammonium concentrations to reconstruct fire activity from the North Greenland Eemian (NEEM) ice cores (77.49° N; 51.2° W, 2480 m a.s.l.) over the past 2000 years. Increases in boreal fire activity (1000–1300 CE and 1500–1700 CE) over multi-decadal timescales coincide with the most extensive central and northern Asian droughts of the past two millennia. The NEEM biomass burning tracers coincide with temperature changes throughout much of the past 2000 years except for during the extreme droughts, when precipitation changes are the dominant factor. Many of these multi-annual droughts are caused by monsoon failures, thus suggesting a connection between low and high latitude climate processes. North America is a primary source of biomass burning aerosols due to its relative proximity to the NEEM camp. During major fire events, however, isotopic analyses of dust, back-trajectories and links with levoglucosan peaks and regional drought reconstructions suggest that Siberia is also an important source of pyrogenic aerosols to Greenland.

The effect of fires on susceptibility of subalpine forests to a 19th century spruce beetle outbreak in western Colorado

2006 ◽  
Vol 36 (11) ◽  
pp. 2974-2982 ◽  
Author(s):  
Dominik Kulakowski ◽  
Thomas T Veblen
Keyword(s):  
19Th Century ◽  
Fire History ◽  
Abies Lasiocarpa ◽  
Subalpine Forests ◽  
Dendroctonus Rufipennis ◽  
The Past ◽  
Engelmann Spruce ◽  
Spruce Beetle ◽  
History Of ◽  
Colorado Rocky Mountains

In the subalpine forests of the Colorado Rocky Mountains, research on disturbances that have occurred over the past several decades has shown that prior occurrence of disturbances can alter the extent and severity of subsequent disturbances. In the current study, we consider how fire history affected stand susceptibility to a mid-19th century spruce beetle (Dendroctonus rufipennis Kirby 1837) outbreak. Twenty-one sites were randomly located in an Engelmann spruce – subalpine fir (Picea engelmannii Parry ex Engelm. – Abies lasiocarpa (Hook.) Nutt.) forest across ~2000 km2 of the Grand Mesa area, Colorado. At each site, dendrochronological methods were used to reconstruct the history of severe fires and beetle outbreak. Stand-origin dates were estimated by collecting increment cores from 20–27 of the largest trees at each sample site. The beetle outbreak was reconstructed based on coincident releases among nonhost trees that survived the outbreak. Forest stands originated following severe fires in ca. 1790, ca. 1740, and ca. 1700. The 1840's outbreak affected 67% of these stands. Stands that initiated following the ca. 1790 fire were less susceptible to the outbreak than older stands. These findings indicate that stand-replacing fires have mitigated susceptibility to outbreaks of spruce beetles not only during recent outbreaks, but also over the past centuries.

The Past as Prelude to the Future for Understanding 21st-Century Climate Effects on Rocky Mountain Trout

Fisheries ◽  
2012 ◽  
Vol 37 (12) ◽  
pp. 542-556 ◽  
Author(s):  
Daniel J. Isaak ◽  
Clint C. Muhlfeld ◽  
Andrew S. Todd ◽  
Robert Al-chokhachy ◽  
James Roberts ◽  
...  
Keyword(s):  
21St Century ◽  
Rocky Mountain ◽  
Climate Effects ◽  
The Past ◽  
The Future

scholarly journals Fire in ice: two millennia of boreal forest fire history from the Greenland NEEM ice core

2014 ◽  
Vol 10 (5) ◽  
pp. 1905-1924 ◽  
Author(s):  
P. Zennaro ◽  
N. Kehrwald ◽  
J. R. McConnell ◽  
S. Schüpbach ◽  
O. J. Maselli ◽  
...  
Keyword(s):  
Black Carbon ◽  
Biomass Burning ◽  
High Latitude ◽  
Fire History ◽  
Global Climate ◽  
Ice Cores ◽  
Back Trajectories ◽  
The Past ◽  
Isotopic Analyses ◽  
Fire Activity

Abstract. Biomass burning is a major source of greenhouse gases and influences regional to global climate. Pre-industrial fire-history records from black carbon, charcoal and other proxies provide baseline estimates of biomass burning at local to global scales spanning millennia, and are thus useful to examine the role of fire in the carbon cycle and climate system. Here we use the specific biomarker levoglucosan together with black carbon and ammonium concentrations from the North Greenland Eemian (NEEM) ice cores (77.49° N, 51.2° W; 2480 m a.s.l) over the past 2000 years to infer changes in boreal fire activity. Increases in boreal fire activity over the periods 1000–1300 CE and decreases during 700–900 CE coincide with high-latitude NH temperature changes. Levoglucosan concentrations in the NEEM ice cores peak between 1500 and 1700 CE, and most levoglucosan spikes coincide with the most extensive central and northern Asian droughts of the past millennium. Many of these multi-annual droughts are caused by Asian monsoon failures, thus suggesting a connection between low- and high-latitude climate processes. North America is a primary source of biomass burning aerosols due to its relative proximity to the Greenland Ice Cap. During major fire events, however, isotopic analyses of dust, back trajectories and links with levoglucosan peaks and regional drought reconstructions suggest that Siberia is also an important source of pyrogenic aerosols to Greenland.

scholarly journals Vegetation response to wildfire and climate forcing in a Rocky Mountain lodgepole pine forest over the past 2500 years

The Holocene ◽  
2020 ◽  
Vol 30 (11) ◽  
pp. 1493-1503
Author(s):  
Barrie V Chileen ◽  
Kendra K McLauchlan ◽  
Philip E Higuera ◽  
Meredith Parish ◽  
Bryan N Shuman
Keyword(s):  
Pinus Contorta ◽  
Vegetation Change ◽  
Fire History ◽  
Lodgepole Pine ◽  
Rocky Mountain ◽  
Pine Forest ◽  
The Past ◽  
High Severity ◽  
Decadal Scale ◽  
Pollen Types

Wildfire is a ubiquitous disturbance agent in subalpine forests in western North America. Lodgepole pine ( Pinus contorta var. latifolia), a dominant tree species in these forests, is largely resilient to high-severity fires, but this resilience may be compromised under future scenarios of altered climate and fire activity. We investigated fire occurrence and post-fire vegetation change in a lodgepole pine forest over the past 2500 years to understand ecosystem responses to variability in wildfire and climate. We reconstructed vegetation composition from pollen preserved in a sediment core from Chickaree Lake, Colorado, USA (1.5-ha lake), in Rocky Mountain National Park, and compared vegetation change to an existing fire history record. Pollen samples ( n = 52) were analyzed to characterize millennial-scale and short-term (decadal-scale) changes in vegetation associated with multiple high-severity fire events. Pollen assemblages were dominated by Pinus throughout the record, reflecting the persistence of lodgepole pine. Wildfires resulted in significant declines in Pinus pollen percentages, but pollen assemblages returned to pre-fire conditions after 18 fire events, within c.75 years. The primary broad-scale change was an increase in Picea, Artemisia, Rosaceae, and Arceuthobium pollen types, around 1155 calibrated years before present. The timing of this change is coincident with changes in regional pollen records, and a shift toward wetter winter conditions identified from regional paleoclimate records. Our results indicate the overall stability of vegetation in Rocky Mountain lodgepole pine forests during climate changes and repeated high-severity fires. Contemporary deviations from this pattern of resilience could indicate future recovery challenges in these ecosystems.

Holocene fire history reconstruction of a mid-elevation mixed-conifer forest in the Eastern Cascades, Washington (USA)

The Holocene ◽  
2021 ◽  
pp. 095968362098803
Author(s):  
Zoe A Rushton ◽  
Megan K Walsh
Keyword(s):  
Fire History ◽  
Fire Regime ◽  
Fire Severity ◽  
Fire Regimes ◽  
Conifer Forest ◽  
Mixed Conifer ◽  
The Past ◽  
Mixed Conifer Forest ◽  
Fire Activity ◽  
Eastern Cascades

Fire histories of mid-elevation mixed-conifer forests are uncommon in the eastern Cascades, limiting our understanding of long-term fire dynamics in these environments. The purpose of this study was to reconstruct the fire and vegetation history for a moist mid-elevation mixed-conifer site, and to determine whether Holocene fire activity in this watershed was intermediate to fire regimes observed at higher and lower elevations in the eastern Cascades. Fire activity and vegetation change was reconstructed using macroscopic charcoal and pollen analysis of sediment core from Long Lake. This site is located ~45 km west of Yakima, WA, and exists in a grand fir-dominated, mixed-conifer forest. Results show low fire activity from ca. 9870 to 6000 cal yr BP, after which time fire increased and remained frequent until ca. 500 cal yr BP. A woodland environment existed at the site in the early Holocene, with the modern coniferous forest establishing ca. 6000–5500 cal yr BP. A mixed-severity fire regime has existed at the site for the past ~6000 years, with both higher- and lower-severity fire episodes occurring on average every ~80–100 years. However, only one fire episode occurred in the Long Lake watershed during the past 500 years, and none within the past ~150 years. Based on a comparison with other eastern Cascade sites, Holocene fire regimes at Long Lake, particularly during the late Holocene, appear to be intermediate between those observed at higher- and lower elevation sites, both in terms of fire severity and frequency.

Gradually increasing forest fire activity during the Holocene in the northern Ural region (Komi Republic, Russia)

The Holocene ◽  
2019 ◽  
Vol 29 (12) ◽  
pp. 1906-1920 ◽  
Author(s):  
Chéïma Barhoumi ◽  
Odile Peyron ◽  
Sébastien Joannin ◽  
Dmitri Subetto ◽  
Alexander Kryshen ◽  
...  
Keyword(s):  
Forest Fire ◽  
Fire History ◽  
Gradual Increase ◽  
Komi Republic ◽  
Ecosystem Dynamics ◽  
Ural Mountain ◽  
The Holocene ◽  
The Past ◽  
Fire Activity ◽  
The Impact

In many boreal regions of Russia the past natural variability of forest fire activity remains largely undocumented, preventing accurate assessment of the impact of current climate warming on forest ecosystem dynamics. This study aims to reconstruct the Holocene fire history of the northern Ural mountain foothills, in the Komi Republic, based on analyses of charcoal particles from peatland deposits and coupled with dendrochronological investigations. The results show that there was a gradual increase in forest fire activity during the past 11,000 years. Between 11,000 and 5100 cal. yr BP, the mean fire return interval (FRI) oscillated between 600 and 200 years. During this period, regional data showed that cold temperature, humid climatic conditions, combined with steppe vegetation between 11,000–9000 cal. BP, and then the development of spruce-dominated forest between 9300 and 4600 cal. yr BP, were less conducive to fires. After 5100 cal. yr BP, a gradual increase in drought conditions through reduced precipitations, associated with the establishment of a Scots pine forest favored fire frequency, with a mean FRI under 200 years (range, 200–40 years). Nowadays (since CE 1500), human activity induces an unprecedented fire activity with a mean FRI below 100 years (range, 100–40 years).

Remembering the Past in Nineteenth-Century Scotland

2014 ◽  
Author(s):  
James J. Coleman
Keyword(s):  
Nineteenth Century ◽  
National Identity ◽  
19Th Century ◽  
21St Century ◽  
Collective Memories ◽  
The Past ◽  
Prevailing View ◽  
The Way

At a time when the Union between Scotland and England is once again under the spotlight, Remembering the Past in Nineteenth-Century Scotland examines the way in which Scotland’s national heroes were once remembered as champions of both Scottish and British patriotism. Whereas 19th-century Scotland is popularly depicted as a mire of sentimental Jacobitism and kow-towing unionism, this book shows how Scotland’s national heroes were once the embodiment of a consistent, expressive and robust view of Scottish nationality. Whether celebrating the legacy of William Wallace and Robert Bruce, the reformer John Knox, the Covenanters, 19th-century Scots rooted their national heroes in a Presbyterian and unionist view of Scotland’s past. Examined through the prism of commemoration, this book uncovers collective memories of Scotland’s past entirely opposed to 21st-century assumptions of medieval proto-nationalism and Calvinist misery. Detailed studies of 19th-century commemoration of Scotland’s national heroes Uncovers an all but forgotten interpretation of these ‘great Scots’ Shines a new light on the mindset of nineteenth-century Scottish national identity as being comfortably Scottish and British Overturns the prevailing view of Victorian Scottishness as parochial, sentimental tartanry

scholarly journals Exploring the past of Mavrovouni forest in the Pindus Mountain range (Greece) using tree rings of Bosnian pines

Trees ◽  
2021 ◽  
Author(s):  
Anastasia Christopoulou ◽  
Nikolaos M. Fyllas ◽  
Barbara Gmińska-Nowak ◽  
Yasemin Özarslan ◽  
Margarita Arianoutsou ◽  
...  
Keyword(s):  
Fire History ◽  
Ring Width ◽  
Severe Drought ◽  
Mountain Range ◽  
Degree Days ◽  
Mature Trees ◽  
The Past ◽  
Natural Agent ◽  
Fire Ignition ◽  
Animal Grazing

Abstract Key message Long Bosnian pine chronologies from different mountains are shaped by different climatic parameters and can help identify past drought events and reconstruct landscape histories. Abstract We developed a 735-year-long Pinus heldreichii chronology from the southern distribution limit of the species, expanding the available database of long Bosnian pine chronologies. Tree-ring growth was mainly positively correlated with growing degree days (GDD: r1950–2018 = 0.476) while higher temperatures during both winter and growing season also enhanced growth (TWT: r1950–2018 = 0.361 and TGS: 0.289, respectively). Annual precipitation, during both calendar and water years, had a negative but weaker impact on annual tree growth. The newly developed chronology correlates well with chronologies developed from the neighboring mountains. The years with ring width index (RWI) lower than the average were found to correspond to cool years with dry summers. Still, the newly developed chronology was able to capture severe drought events, such as those in 1660, 1687, and 1725. Several old living trees had internal scars presumably caused by fires. Therefore, old mature trees could be used for fire history reconstruction in addition to climate reconstruction. Although the presence of lightning scars indicates an important natural agent of fire ignition, human activities associated with animal grazing could also be an underlying reason for fires in the region.

scholarly journals Twenty-first century droughts have not increasingly exacerbated fire season severity in the Brazilian Amazon

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
R. Libonati ◽  
J. M. C. Pereira ◽  
C. C. Da Camara ◽  
L. F. Peres ◽  
D. Oom ◽  
...  
Keyword(s):  
Forest Fires ◽  
Brazilian Amazon ◽  
First Century ◽  
Fire Season ◽  
Fire Intensity ◽  
Amazon Forest ◽  
Active Fire ◽  
Fire Activity ◽  
Twenty First Century ◽  
In Fire

AbstractBiomass burning in the Brazilian Amazon is modulated by climate factors, such as droughts, and by human factors, such as deforestation, and land management activities. The increase in forest fires during drought years has led to the hypothesis that fire activity decoupled from deforestation during the twenty-first century. However, assessment of the hypothesis relied on an incorrect active fire dataset, which led to an underestimation of the decreasing trend in fire activity and to an inflated rank for year 2015 in terms of active fire counts. The recent correction of that database warrants a reassessment of the relationships between deforestation and fire. Contrasting with earlier findings, we show that the exacerbating effect of drought on fire season severity did not increase from 2003 to 2015 and that the record-breaking dry conditions of 2015 had the least impact on fire season of all twenty-first century severe droughts. Overall, our results for the same period used in the study that originated the fire-deforestation decoupling hypothesis (2003–2015) show that decoupling was clearly weaker than initially proposed. Extension of the study period up to 2019, and novel analysis of trends in fire types and fire intensity strengthened this conclusion. Therefore, the role of deforestation as a driver of fire activity in the region should not be underestimated and must be taken into account when implementing measures to protect the Amazon forest.

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