scholarly journals Holocene fire in Fennoscandia and Denmark

2014 ◽  
Vol 23 (6) ◽  
pp. 781 ◽  
Author(s):  
Jennifer L. Clear ◽  
Chiara Molinari ◽  
Richard H. W. Bradshaw
Keyword(s):  
Land Use ◽  
Biomass Burning ◽  
Late Holocene ◽  
Fire History ◽  
Fire Regime ◽  
Fire Suppression ◽  
Anthropogenic Activity ◽  
Natural Fire ◽  
Fire Scar ◽  
Anthropogenic Land Use

Natural disturbance dynamics, such as fire, have a fundamental control on forest composition and structure. Knowledge of fire history and the dominant drivers of fire are becoming increasingly important for conservation and management practice. Temporal and spatial variability in biomass burning is examined here using 170 charcoal and 15 fire scar records collated throughout Fennoscandia and Denmark. The changing fire regime is discussed in relation to local biogeographical controls, regional climatic change, anthropogenic land use and fire suppression. The region has experienced episodic variability in the dominant drivers of biomass burning throughout the Holocene, creating a frequently changing fire regime. Early Holocene biomass burning appears to be driven by fuel availability. Increased continentality during the mid-Holocene Thermal Maximum coincides with an increase in fire. The mid–late Holocene front-like spread of Picea abies (Norway spruce) and cooler, wetter climatic conditions reduce local biomass burning before the onset of intensified anthropogenic land use, and the late Holocene increase in anthropogenic activity created artificially high records of biomass burning that overshadowed the natural fire signal. An economic shift from extensive subsistence land use to agriculture and forestry as well as active fire suppression has reduced regional biomass burning. However, it is proposed that without anthropogenic fire suppression, the underlying natural fire signal would remain low because of the now widespread dominance of P. abies.

Mapping fuels in Yosemite National Park

2013 ◽  
Vol 43 (1) ◽  
pp. 7-17 ◽  
Author(s):  
Seth H. Peterson ◽  
Janet Franklin ◽  
Dar A. Roberts ◽  
Jan W. van Wagtendonk
Keyword(s):  
Random Forests ◽  
National Park ◽  
Fire History ◽  
Fire Regime ◽  
Fire Suppression ◽  
Remotely Sensed ◽  
Yosemite National Park ◽  
Natural Fire ◽  
Fuel Loads ◽  
Fuel Models

Decades of fire suppression have led to unnaturally large accumulations of fuel in some forest communities in the western United States, including those found in lower and midelevation forests in Yosemite National Park in California. We employed the Random Forests decision tree algorithm to predict fuel models as well as 1-h live and 1-, 10-, and 100-h dead fuel loads using a suite of climatic, topographic, remotely sensed, and burn history predictor variables. Climate variables and elevation consistently were most useful for predicting all types of fuels, but remotely sensed variables increased the kappa accuracy metric by 5%–12% age points in each case, demonstrating the utility of using disparate data sources in a topographically diverse region dominated by closed-canopy vegetation. Fire history information (time-since-fire) generally only increased kappa by 1% age point, and only for the largest fuel classes. The Random Forests models were applied to the spatial predictor layers to produce maps of fuel models and fuel loads, and these showed that fuel loads are highest in the low-elevation forests that have been most affected by fire suppression impacting the natural fire regime.

Stratigraphic Charcoal Analysis on Petrographic Thin Sections: Application to Fire History in Northwestern Minnesota

1988 ◽  
Vol 30 (1) ◽  
pp. 81-91 ◽  
Author(s):  
James S. Clark
Keyword(s):  
Lake Sediments ◽  
Fire History ◽  
Fire Regime ◽  
Fire Suppression ◽  
Fire Regimes ◽  
Charcoal Analysis ◽  
Fire Scars ◽  
Good Correspondence ◽  
Thin Sections ◽  
Fire Scar

Results of stratigraphic charcoal analysis from thin sections of varved lake sediments have been compared with fire scars on red pine trees in northwestern Minnesota to determine if charcoal data accurately reflect fire regimes. Pollen and opaque-spherule analyses were completed from a short core to confirm that laminations were annual over the last 350 yr. A good correspondence was found between fossil-charcoal and fire-scar data. Individual fires could be identified as specific peaks in the charcoal curves, and times of reduced fire frequency were reflected in the charcoal data. Charcoal was absent during the fire-suppression era from 1920 A.D. to the present. Distinct charcoal maxima from 1864 to 1920 occurred at times of fire within the lake catchment. Fire was less frequent during the 19th century, and charcoal was substantially less abundant. Fire was frequent from 1760 to 1815, and charcoal was abundant continuously. Fire scars and fossil charcoal indicate that fires did not occur during 1730–1750 and 1670–1700. Several fires occurred from 1640 to 1670 and 1700 to 1730. Charcoal counted from pollen preparations in the area generally do not show this changing fire regime. Simulated “sampling” of the thin-section data in a fashion comparable to pollen-slide methods suggests that sampling alone is not sufficient to account for differences between the two methods. Integrating annual charcoal values in this fashion still produced much higher resolution than the pollen-slide method, and the postfire suppression decline of charcoal characteristic of my method (but not of pollen slides) is still evident. Consideration of the differences in size of fragments counted by the two methods is necessary to explain charcoal representation in lake sediments.

Late Holocene ecosystem change and disturbance dynamics in central European mountain forests

2020 ◽  
Author(s):  
Niina Kuosmanen ◽  
Petr Kuneš ◽  
Karen Halsall ◽  
Helena Svitavska Svobodova ◽  
Jana Beranova ◽  
...  
Keyword(s):  
Human Activity ◽  
Late Holocene ◽  
Fire History ◽  
Fire Regime ◽  
Ecosystem Dynamics ◽  
Ecosystem Change ◽  
Anthropogenic Activity ◽  
Climate Data ◽  
Disturbance Dynamics ◽  
The Past

<p>Investigating past changes in temperate mountain spruce forest ecosystems and the processes behind them can provide valuable information for understanding present and future ecosystem dynamics. To assess the late Holocene ecosystem change and disturbance history in mountain spruce forests, we sampled four small forest hollows from the High Tatra mountains in Slovakia.  </p><p>We use pollen analysis to reconstruct changes in forest composition over the last circa 5000 cal. yr BP. Fire history is analysed using macroscopic charcoal counts and charcoal area measurements. As disturbance is one of the key factors shaping mountain forest dynamics, the analysed pollen records will be processed with a new method quantifying disturbance based on plant ecological indices (Kuneš et al. 2019). These indices for disturbance will be attributed to pollen taxa and then disturbance frequency and severity for the whole community will be calculated. We assess the role of climate and human impact as potential drivers on the past forest and disturbance dynamics. The climate variable will be constructed from modelled climate data for the last 4000 years and for the past 1000 years we will use climate reconstruction from the tree-ring records from the region. We use human indicator pollen taxa as the variable for human influence on ecosystem dynamics, and to indicate human activity in the region.</p><p>Preliminary results demonstrate opening of the landscape circa 800-500 cal. yr BP in connection with a change in the disturbance regime as indicated by the disturbance indices. The presence of human indicator pollen taxa in all small hollow records suggest landscape opening in connection with anthropogenic activity in the region. In addition, the charcoal records demonstrate periods of fire, which coincide with the opening of landscape and it is plausible that change in the fire regime is connected to the intensified human activity in the region. These results will be discussed further in the presentation in the light of climate data and further data analysis.</p><p>Reference:</p><p>Kuneš, P. Abraham, V. & Herben, T. 2019. Changing disturbance-diversity relationships in temperate ecosystems over the past 12 000 years. Journal of Ecology 107:1678–1688.</p>

Reconstruction of fire regime changes in the French Mediterranean region during the last 8,500 years using microcharcoal 

2021 ◽  
Author(s):  
Marion Genet ◽  
Anne-Laure Daniau ◽  
Maria-Angela Bassetti ◽  
Bassem Jallali ◽  
Marie-Alexandrine Sicre ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Mediterranean Region ◽  
Fire History ◽  
Fine Particles ◽  
Fire Regime ◽  
Hot Spot ◽  
Sediment Delivery ◽  
Climate Conditions ◽  
North West ◽  
Gulf Of Lion

<p>Nowadays, the Mediterranean region is strongly impacted by fires. Projected warming scenarios suggest increasing fire risk in this region considered as hot-spot of the climate change (Liu et al., 2010; Pechony and Shindell, 2010). However, models based on modern-day statistical relationships do not properly account for interactions between climate, vegetation, and fire. In addition, process-based models must be tested not only against modern observations but also under different past climate conditions reflecting the range of climate variability projected for the next centuries (Hantson et al. 2016). Marine sediments are a major source of fire history of nearby land masses. Here, we present a unique 8,500 yr long record of biomass burning changes from southeastern France based on a marine microcharcoal sedimentary record from the Gulf of Lion, located in the subaqueous Rhone river delta. Sediment delivery to the Gulf of Lion comes mainly from the Rhône River draining a large watershed in southeast France (ca.100,000 km2). Due to the direction of dominant winds blowing from the North-North-West (Mistral and Tramontane) and carrying fine particles from the land to the sea, the microcharcoal record likely reflects the biomass burning in the Rhone watershed and South-East of France. Our results show multi-centennial to millennial changes in biomass burning with a periodicity  of 1000 years for the full record and between 500 and 700 years before 5,000 cal BP and after 3,000 cal BP. Large peaks of biomass burning are associated with marked dry periods observed in the region. Burning of biomass is higher when the region is dominated by xerophytic vegetation than when mesophyte vegetation dominates. The trend and periodicity of the biomass burning record suggest a predominant climatic control of fire occurrences since 8,500 cal BP in this region.</p>

Fire regimes and their correlates in the Darwin region of northern Australia

2007 ◽  
Vol 13 (3) ◽  
pp. 177 ◽  
Author(s):  
Owen Price ◽  
Bryan Baker
Keyword(s):  
Fire History ◽  
Ad Hoc ◽  
Fire Regime ◽  
Negative Impact ◽  
Fire Suppression ◽  
Landsat Imagery ◽  
Fire Regimes ◽  
Fire Frequency ◽  
Dry Season ◽  
Generalized Linear Modelling

A nine year fire history for the Darwin region was created from Landsat imagery, and examined to describe the fire regime across the region. 43% of the region burned each year, and approximately one quarter of the fires occur in the late dry season, which is lower than most other studied areas. Freehold land, which covers 35% of the greater Darwin region, has 20% long-unburnt land. In contrast, most publicly owned and Aboriginal owned land has very high fire frequency (60-70% per year), and only 5% long unburnt. It seems that much of the Freehold land is managed for fire suppression, while the common land is burnt either to protect the Freehold or by pyromaniacs. Generalized Linear Modelling among a random sample of points revealed that fire frequency is higher among large blocks of savannah vegetation, and at greater distances from mangrove vegetation and roads. This suggests that various kinds of fire break can be used to manage fire in the region. The overall fire frequency in the Darwin region is probably too high and is having a negative impact on wildlife. However, the relatively low proportion of late dry season fires means the regime is probably not as bad as in some other regions. The management of fire is ad-hoc and strongly influenced by tenure. There needs to be a clear statement of regional fire targets and a strategy to achieve these. Continuation of the fire mapping is an essential component of achieving the targets.

scholarly journals Fire history in Andean Araucaria–Nothofagus forests: coupled influences of past human land-use and climate on fire regimes in north-west Patagonia

2020 ◽  
Vol 29 (8) ◽  
pp. 649 ◽  
Author(s):  
Mauro E. González ◽  
Ariel A. Muñoz ◽  
Álvaro González-Reyes ◽  
Duncan A. Christie ◽  
Jason Sibold
Keyword(s):  
Climate Change ◽  
Land Use ◽  
Fire History ◽  
Fire Regime ◽  
Fire Regimes ◽  
Forest Landscape ◽  
Araucaria Forest ◽  
North West ◽  
Human Land Use ◽  
Nothofagus Forests

Historical fire regimes are critical for understanding the potential effects of changing climate and human land-use on forest landscapes. Fire is a major disturbance process affecting the Andean Araucaria forest landscape in north-west Patagonia. The main goals of this study were to reconstruct the fire history of the Andean Araucaria–Nothofagus forests and to evaluate the coupled influences of climate and humans on fire regimes. Reconstructions of past fires indicated that the Araucaria forest landscape has been shaped by widespread, stand-replacing fires favoured by regional interannual climate variability related to major tropical and extratropical climate drivers in the southern hemisphere. Summer precipitation and streamflow reconstructions tended to be below average during fire years. Fire events were significantly related to positive phases of the Southern Annular Mode and to warm and dry summers following El Niño events. Although Euro-Chilean settlement (1883–1960) resulted in widespread burning, cattle ranching by Pehuenche Native Americans during the 18th and 19th centuries also appears to have changed the fire regime. In the context of climate change, two recent widespread wildfires (2002 and 2015) affecting Araucaria forests appear to be novel and an early indication of a climate change driven shift in fire regimes in north-west Patagonia.

scholarly journals Socioecological transitions trigger fire regime shifts and modulate fire–climate interactions in the Sierra Nevada, USA, 1600–2015 CE

2016 ◽  
Vol 113 (48) ◽  
pp. 13684-13689 ◽  
Author(s):  
Alan H. Taylor ◽  
Valerie Trouet ◽  
Carl N. Skinner ◽  
Scott Stephens
Keyword(s):  
Climate Change ◽  
Native American ◽  
Sierra Nevada ◽  
Fire History ◽  
Climate Models ◽  
Fire Regime ◽  
Fire Suppression ◽  
Gold Rush ◽  
Climatic Effects ◽  
Fire Activity

Large wildfires in California cause significant socioecological impacts, and half of the federal funds for fire suppression are spent each year in California. Future fire activity is projected to increase with climate change, but predictions are uncertain because humans can modulate or even override climatic effects on fire activity. Here we test the hypothesis that changes in socioecological systems from the Native American to the current period drove shifts in fire activity and modulated fire–climate relationships in the Sierra Nevada. We developed a 415-y record (1600–2015 CE) of fire activity by merging a tree-ring–based record of Sierra Nevada fire history with a 20th-century record based on annual area burned. Large shifts in the fire record corresponded with socioecological change, and not climate change, and socioecological conditions amplified and buffered fire response to climate. Fire activity was highest and fire–climate relationships were strongest after Native American depopulation—following mission establishment (ca. 1775 CE)—reduced the self-limiting effect of Native American burns on fire spread. With the Gold Rush and Euro-American settlement (ca. 1865 CE), fire activity declined, and the strong multidecadal relationship between temperature and fire decayed and then disappeared after implementation of fire suppression (ca. 1904 CE). The amplification and buffering of fire–climate relationships by humans underscores the need for parameterizing thresholds of human- vs. climate-driven fire activity to improve the skill and value of fire–climate models for addressing the increasing fire risk in California.

Fire history and vegetation pattern of coniferous forests in Jasper National Park, Albert

1979 ◽  
Vol 57 (18) ◽  
pp. 1912-1931 ◽  
Author(s):  
Gerald F. Tande
Keyword(s):  
National Park ◽  
Fire History ◽  
Fire Suppression ◽  
Temporal Frequency ◽  
Structural Heterogeneity ◽  
Vegetation Pattern ◽  
Forest Patches ◽  
Jasper National Park ◽  
Fire Scar ◽  
High Elevations

Periodicity, location, extent, and severity of fires from 1665 to 1975 were determined for a 43 200-ha area of Jasper National Park using fire-scar dendrochronology. Before fire suppression began in 1913, there were 46 fires with a mean fire return interval (MFRI) of 5.5 years. Twenty-four fires each covered more than 500 ha and had a MFRI of 8.4 years. Fires covering more than 50% of the area had a MFRI of 65.5 years. Present forests originated primarily after the fires of 1889, 1847, and 1758. Most fires between 1665 and 1913 were low to medium intensity, but higher intensities did occur. Interaction of fire periodicity, intensity, and extent determined age, size, density, crown height, and temporal frequency of forest patches. Stands varied from even-age- to multiple-age-classes intermingled over short distances. Multiple-aged stands dominated lower elevations and were maintained by frequent removal, by fire, of low organic matter accumulations. Large, continuous, even-aged forests occurred at mid to high elevations where mesic moisture regimes allowed greater fuel accumulations, and consequently, more intense fires during droughts. Fire periodicity and extent have declined since 1913, accompanied by reduced structural heterogeneity of the forests.

scholarly journals Five thousand years of fire history in the high North Atlantic region: natural variability and ancient human forcing

2021 ◽  
Vol 17 (4) ◽  
pp. 1533-1545
Author(s):  
Delia Segato ◽  
Maria Del Carmen Villoslada Hidalgo ◽  
Ross Edwards ◽  
Elena Barbaro ◽  
Paul Vallelonga ◽  
...  
Keyword(s):  
Black Carbon ◽  
Biomass Burning ◽  
North Atlantic ◽  
Atmospheric Chemistry ◽  
Fire History ◽  
Fire Regime ◽  
Ice Core ◽  
North Atlantic Region ◽  
Atlantic Region ◽  
Ice Cap

Abstract. Biomass burning influences global atmospheric chemistry by releasing greenhouse gases and climate-forcing aerosols. There is controversy about the magnitude and timing of Holocene changes in biomass burning emissions from millennial to centennial timescales and, in particular, about the possible impact of ancient civilizations. Here we present a 5 kyr record of fire activity proxies levoglucosan, black carbon, and ammonium measured in the RECAP (Renland ice cap) ice core, drilled in coastal eastern Greenland, and therefore affected by processes occurring in the high North Atlantic region. Levoglucosan and ammonium fluxes are high from 5 to 4.5 kyr BP (thousand years before 2000 CE) followed by an abrupt decline, possibly due to monotonic decline in Northern Hemisphere summer insolation. Levoglucosan and black carbon show an abrupt decline at 1.1 kyr BP, suggesting a decline in the wildfire regime in Iceland due to the extensive land clearing caused by Viking colonizers. All fire proxies reach a minimum during the second half of the last century, after which levoglucosan and ammonium fluxes increase again, in particular over the last 200 years. We find that the fire regime reconstructed from RECAP fluxes seems mainly related to climatic changes; however over the last millennium human activities might have influenced wildfire frequency/occurrence substantially.

scholarly journals Fire Histoy Determination in the Mixed Conifer/Aspen Community of Bryce Canyon National Park

1993 ◽  
Vol 17 ◽  
pp. 31-35
Author(s):  
Michael Jenkins
Keyword(s):  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
National Park ◽  
Fire History ◽  
Fire Regime ◽  
Mixed Conifer ◽  
Major Objective ◽  
Ponderosa Pine Forests ◽  
Fire Scar ◽  
European Settlement

The major objective of this ongoing study is to document vegetative changes resulting from alteration of the fire regime in the mixed conifer/aspen communities of Bryce Canyon National Park. Previous fire history studies have documented fire return intervals using fire scar analysis of ponderosa pine Pinus ponderosa in the park (Buchannan and Tolman 1983: Wight 1989) and for the Paunsaugunt Plateau (Stein 1988). Numerous other studies have similarly documented the fire regime in pre-European settlement ponderosa pine forests in western North America. The study is being conducted in the more mesic mixed conifer communities at the south end of Bryce Canyon National Park and will specifically document vegetative changes suggested by Roberts et al. (1992) resulting from suppression of frequent low intensity surface fires and overgrazing.

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