scholarly journals Late Holocene fire history documented at Lake Khamra, SW Yakutia (Eastern Siberia)

2020 ◽  
Author(s):  
Ramesh Glückler ◽  
Ulrike Herzschuh ◽  
Luidmila Pestryakova ◽  
Stefan Kruse ◽  
Stuart Vyse ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Boreal Forests ◽  
Late Holocene ◽  
Fire History ◽  
The Arctic ◽  
Permafrost Degradation ◽  
Reconstructed Temperature ◽  
Fire Activity ◽  
Microscopic Charcoal ◽  
Macroscopic Charcoal

<p>Recent large-scale fire events in Siberia have drawn increased attention to boreal forest fire history. Boreal forests contain about 25% of all global biomass and act as an enormous carbon storage. Fire events are important ecological disturbances connected to the overarching environmental changes that face the Arctic and Subarctic, like vegetation dynamics, permafrost degradation, changes in soil nutrient cycling and global warming, and act as the dominant driver behind boreal forest’s landscape carbon balance. By looking into past fire regimes we can learn about fire frequency and potential linkages to other environmental factors, e.g. fuel types, reconstructed temperature/humidity or geomorphologic landscape dynamics. Unfortunately, fire history data is still very sparse in large parts of Siberia, a region strongly influenced by climate change. The Global Charcoal Database (www.paleofire.org) lists only a handful of continuous charcoal records for all of Siberia, with only three of those featuring published data from macroscopic charcoal as opposed to microscopic charcoal from pollen slides.</p><p>We aim to reconstruct the late Holocene fire history using lacustrine sediments of Lake Khamra (SW Yakutia at N 59.99°, E 112.98°). It covers an area of c. 4.6 km² with about 22 m maximum water depth, located within the zone of transition from summer-green and larch-dominated to evergreen boreal forest. We present the first continuous, high-resolution (c. 10 years/sample) macroscopic charcoal record (> 150 μm) including information on particle size and morphology for the past c. 2200 years. We compare this to complementary information from microscopic charcoal in pollen slides, a pollen and non-pollen palynomorph record as well as μXRF data. This multi-proxy approach adds valuable data about fire activity in the region and allows a comparison of different prevalent fire reconstruction methods. As the first record of its kind from Siberia, it provides a long-term context for current fire activity in central Siberian boreal forests and enables a better understanding of the environmental interactions occurring in the changing subarctic landscape.</p>

Mid- and Late Holocene vegetation dynamics and fire history in the boreal forest of European Russia: A case study from Meshchera Lowlands

2016 ◽  
Vol 459 ◽  
pp. 570-584 ◽  
Author(s):  
Elena Yu. Novenko ◽  
Andrey N. Tsyganov ◽  
Elena M. Volkova ◽  
Dmitrii A. Kupriyanov ◽  
Iya V. Mironenko ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Vegetation Dynamics ◽  
Late Holocene ◽  
Fire History ◽  
European Russia

scholarly journals Arctic ground squirrel population collapse in the boreal forests of the Southern Yukon

2015 ◽  
Vol 42 (2) ◽  
pp. 176 ◽  
Author(s):  
Jeffery R. Werner ◽  
Charles J. Krebs ◽  
Scott A. Donker ◽  
Rudy Boonstra ◽  
Michael J. Sheriff
Keyword(s):  
Boreal Forest ◽  
Ground Squirrel ◽  
Boreal Forests ◽  
Ground Squirrels ◽  
The Arctic ◽  
Arctic Ground Squirrel ◽  
Forest Zone ◽  
Winter Climate ◽  
Population Collapse ◽  
Predator Pit

Context The arctic ground squirrel (Urocitellus parryii) comprised 17% of the biomass of herbivores in the Yukon boreal forest during the summer months from 1987 to 1996 and was responsible for 23% of the energy flow at the herbivore level. By 2000, ground squirrel populations in this region collapsed to nearly zero and have remained there. Aims We summarise the population monitoring (since 1975) and recent experimental work that has been done on this key herbivore in the Kluane area of the southern Yukon to test one mechanistic hypothesis as the possible explanation for this population collapse and subsequent lack of recovery: predation. Methods Ground squirrels are the preferred summer prey of bird and mammal predators when snowshoe hare (Lepus americanus) populations are declining. We used translocations into formerly occupied habitat and radiotelemetry to determine movements and causes of death from 2009 to 2014. We surveyed 158 sites between 2008 and 2013 to measure the disappearance of colonies in alpine and forest habitats over 25 000 km2. Key results Ground squirrels from 2000 to 2013 comprised a small fraction of the herbivore biomass in the boreal forest zone, down from 17% earlier. Most forest populations (~95%) are currently extinct, whereas just over half (65%) of low-elevation meadow populations are locally extinct. One hypothesis is that ground squirrels in the forest have been driven into a predator pit from which they cannot recover. They remain abundant in alpine tundra (93% occupancy rate) and around airport runways and human habitations (97% occupancy), but there is no apparent dispersal from alpine areas down into the boreal forest. Conclusion The predator pit hypothesis is a likely explanation for the initial collapse and sustained decline in population size from 2000 to 2013. Recent attenuation of the hare cycle and milder winter climate have allowed shrubs to expand throughout the forest, thereby reducing visibility and increasing predation risk. This conclusion will be tested in further research using reintroductions to formerly occupied sites. Implication If the loss of this herbivore from the boreal forest is not reversed, predator pressure on the other major herbivores of the montane forest zone is likely to change significantly.

scholarly journals A Comparative Analysis of Burned Area Datasets in Canadian Boreal Forest in 2000

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Laia Núñez-Casillas ◽  
José Rafael García Lázaro ◽  
José Andrés Moreno-Ruiz ◽  
Manuel Arbelo
Keyword(s):  
Comparative Analysis ◽  
Boreal Forest ◽  
Boreal Forests ◽  
Burned Area ◽  
Diverse Group ◽  
Spatial Accuracy ◽  
Noaa Avhrr ◽  
Fire Activity ◽  
Canadian Boreal Forest ◽  
Area Data

The turn of the new millennium was accompanied by a particularly diverse group of burned area datasets from different sensors in the Canadian boreal forests, brought together in a year of low global fire activity. This paper provides an assessment of spatial and temporal accuracy, by means of a fire-by-fire comparison of the following: two burned area datasets obtained from SPOT-VEGETATION (VGT) imagery, a MODIS Collection 5 burned area dataset, and three different datasets obtained from NOAA-AVHRR. Results showed that burned area data from MODIS provided accurate dates of burn but great omission error, partially caused by calibration problems. One of the VGT-derived datasets (L3JRC) represented the largest number of fire sites in spite of its great overall underestimation, whereas the GBA2000 dataset achieved the best burned area quantification, both showing delayed and very variable fire timing. Spatial accuracy was comparable between the 5 km and the 1 km AVHRR-derived datasets but was remarkably lower in the 8 km dataset leading, us to conclude that at higher spatial resolutions, temporal accuracy was lower. The probable methodological and contextual causes of these differences were analyzed in detail.

Determinants of ~1000-year woody vegetation dynamics at the southern boreal forest margin in Northeast China

2020 ◽  
Author(s):  
Chenyi Zhu ◽  
Hongyan Liu ◽  
Hongya Wang ◽  
Siwen Feng ◽  
Yue Han
Keyword(s):  
Boreal Forest ◽  
Boreal Forests ◽  
Carbon Stock ◽  
Vegetation Change ◽  
Vegetation History ◽  
Permafrost Degradation ◽  
Vegetation Development ◽  
Southern Boundary ◽  
Complete Replacement ◽  
Permafrost Thawing

<p>The most dramatic permafrost degradation is expected to occur at its southernmost distribution, which causes significant vegetation changes in the southernmost boreal forests and consequently affects the carbon stock. To reveal determinants of vegetation change and, in particular, the role of permafrost dynamics, the reconstruction of the long- term vegetation history spanning a warming-cooling cycle is required. Here, we showed that over the last 990 years, vegetation development was characterized by changes in the relative proportions of taxa, such as<em> Larix</em>, <em>Pinus</em> and <em>Corylus</em>, corresponding to the variation in temperature. However, since ~1950 AD, rapid warming has led to the breakdown of the stable relationship among vegetation, climate and permafrost, and the proportion of conifers has shown an increasing trend in the short term due to the influence of permafrost thawing regulated by terrain. In general, we have observed that the coupling system of vegetation, climate and permafrost was stable before ~1950 AD; however, there has been a transition in the most recent rapid warming-induced permafrost thawing. As the southern boundary of permafrost moves northward, it is suspected that the boreal forest in this region will be unstable or may even collapse in the future, and the complete replacement of conifers by broad-leaved trees could greatly reduce the carbon stock in this area by that time.</p>

scholarly journals Seven hundred years of human-driven and climate-influenced fire activity in a British Columbia coastal temperate rainforest

2016 ◽  
Vol 3 (10) ◽  
pp. 160608 ◽  
Author(s):  
Kira M. Hoffman ◽  
Daniel G. Gavin ◽  
Brian M. Starzomski
Keyword(s):  
British Columbia ◽  
Fire History ◽  
Southern Oscillation ◽  
The Arctic ◽  
Climate Indices ◽  
Late Nineteenth Century ◽  
Temperate Rainforest ◽  
Decadal Scale ◽  
Fire Activity ◽  
Temperate Rainforests

While wildland fire is globally most common at the savannah-grassland ecotone, there is little evidence of fire in coastal temperate rainforests. We reconstructed fire activity with a ca 700-year fire history derived from fire scars and stand establishment from 30 sites in a very wet (up to 4000 mm annual precipitation) temperate rainforest in coastal British Columbia, Canada. Drought and warmer temperatures in the year prior were positively associated with fire events though there was little coherence of climate indices on the years of fires. At the decadal scale, fires were more likely to occur after positive El Niño-Southern Oscillation and Pacific Decadal Oscillation phases and exhibited 30-year periods of synchrony with the negative phase of the Arctic Oscillation. Fire frequency was significantly inversely correlated with the distance from former Indigenous habitation sites and fires ceased following cultural disorganization caused by disease and other European impacts in the late nineteenth century. Indigenous people were likely to have been the primary ignition source in this and many coastal temperate rainforest settings. These data are directly relevant to contemporary forest management and discredit the myth of coastal temperate rainforests as pristine landscapes.

Climate Feedbacks in the Alaskan Boreal Forest

2006 ◽  
Author(s):  
F. Stuart Chapin III ◽  
A. David McGuire
Keyword(s):  
Boreal Forest ◽  
Arctic Ocean ◽  
Fresh Water ◽  
Land Surface ◽  
Boreal Forests ◽  
Energy Exchange ◽  
Climate System ◽  
The Arctic ◽  
The Arctic Ocean ◽  
Forest Biome

The boreal forest biome occupies an area of 18.5 million km2, which is approximately 14% of the vegetated cover of the earth’s surface (McGuire et al. 1995b). North of 50°N, terrestrial interactions with the climate system are dominated by the boreal forest biome because of its large aerial extent (Bonan et al. 1992, Chapin et al. 2000b; Fig. 19.1). There are three major pathways through which the function and structure of boreal forests may influence the climate system: (1) water/energy exchange with the atmosphere, (2) the exchange of radiatively active gases with the atmosphere, and (3) delivery of fresh water to the Arctic Ocean. The exchange of water and energy has implications for regional climate that may influence global climate, while the exchange of radiatively active gases and the delivery of fresh water to the Arctic Ocean are processes that could directly influence climate at the global scale. In this chapter, we first discuss the current understanding of the role that boreal forests play in each of these pathways and identify key issues that remain to be explored. We then discuss the implications for the earth’s climate system of likely responses of boreal forests to various dimensions of ongoing global change. Most of the energy that heats the earth’s atmosphere is first absorbed by the land surface and then transferred to the atmosphere. The energy exchange properties of the land surface therefore have a strong direct influence on climate. Boreal forest differs from more southerly biomes in having a long period of snow cover, when white surfaces might be expected to reflect incoming radiation (high albedo) and therefore absorb less energy for transfer to the atmosphere. Observed winter albedo in the boreal forest varies between 0.11 (conifer stands) and 0.21 (deciduous stands; Betts and Ball 1997). This is much closer to the summer albedo (0.08–0.15) than to the winter albedo of tundra (0.6–0.8), which weather models had previously assumed to be appropriate for boreal forests. The incorporation of true boreal albedo into climate models led to substantial improvements in medium-range weather forecasting (Viterbo and Betts 1999).

Postglacial Vegetation and Fire History in the Chirripó Páramo of Costa Rica

1993 ◽  
Vol 40 (1) ◽  
pp. 107-116 ◽  
Author(s):  
Sally P. Horn
Keyword(s):  
Costa Rica ◽  
Late Holocene ◽  
Fire History ◽  
Charcoal Analysis ◽  
Climatic Warming ◽  
Lowland Forest ◽  
Fire Activity ◽  
Ice Retreat ◽  
The Impact ◽  
Cordillera De Talamanca

AbstractPollen and charcoal analysis of a 5.6-m sediment core from Lago de las Morrenas (9°29′N, 83°29′W; 3480 m) provides evidence of postglacial vegetation and fire history in the highlands of the Cordillera de Talamanca, Costa Rica. The site is presently surrounded by treeless páramo vegetation and apparently has been so since deglaciation about 10,000 yr B.P. Pollen spectra suggest no pronounced changes in vegetation since ice retreat. Fires set by people or lightning have burned the páramo repeatedly, with fire activity probably highest during the late Holocene, but these fires have not carved páramo from forest. Pollen percentages for Gramineae and other páramo taxa decline upward, whereas percentages for certain subalpine, lower montane, and lowland forest taxa increase slightly; these changes may reflect the impact of prehistoric human activity or slight upslope migrations of forest taxa owing to climatic warming. There is no clear evidence of higher timberlines during the mid-Holocene.

Fire history and the relationship with late Holocene mining activities in the NW Romanian Carpathians reconstructed from two peat core sequences

2020 ◽  
Author(s):  
Ancuta Petras ◽  
Gabriela Florescu ◽  
Simon M. Hutchinson ◽  
Cécile Brun ◽  
Marie-Claude Bal ◽  
...  
Keyword(s):  
Grain Size ◽  
Late Holocene ◽  
Fire History ◽  
Local Environment ◽  
Anthropogenic Pressure ◽  
Mining Activities ◽  
Bedrock Erosion ◽  
Fire Activity ◽  
Romanian Carpathians ◽  
The Relationship

<p>Little is known about how areas of high ecological value and biodiversity hotpots will be impacted in the long-term by increasing anthropogenic pressure, added to future climate warming. One such example is the Romanian Carpathians, among the richest biogeographical regions in Europe in terms of biodiversity indicators and home to the largest unmanaged old-growth forests in Europe. This area is currently threatened by forest clearance and other anthropogenic land-use change, poor management practices and increased risk to wildfire. Peat bogs are among the most important palaeo-archives for the reconstruction of past environmental changes and disturbance regimes, with the potential to provide the longer-term perspective at a local to regional scale necessary for a sustainable management and restoration of these areas. Here we reconstruct late Holocene fire history and the relationship with anthropogenic disturbance, particularly mining, in a former mining area located in Lapus Mts, NW Romanian Carpathians, based on two peat sequences.</p><p>To reconstruct past fire activity, we used sedimentary macroscopic charcoal and also employed macro-charcoal morphologies to determine the type of material burnt (wood, grass, forbs). Past local soil/bedrock erosion and regional atmospheric pollution from historical mining were reconstructed on the basis of abiotic sediment properties such as elemental geochemistry, magnetic mineral characteristics, organic matter content and particle size. Our results show clear variations in macro-charcoal concentration, which coincide with changes in the geochemical, magnetic and grain-size indicators. Specifically, increases in macro-charcoal concentration, particularly the wood charcoal morphotype, were shortly followed in both cores by marked increases in heavy metal concentration and by enhanced soil and bedrock erosion, as inferred from geochemical, magnetic and grain-size proxies. This suggests increased local disturbance during intervals with mining activities and indicates the likelihood that humans used fire to clear the forests and open the access to the mining sites. Such actions likely resulted in topsoil removal and bedrock left exposed to environmental and climatic factors. Over the last centuries, the recovery of the local environment is evident in the proxies, with low fire activity and low soil/bedrock erosion, which coincides with the cessation of local mining activities. </p><p>By showing both impact and recovery of the landscape, our study offers insight into the past evolution of this area and can be used to predict future possible responses of the local environment to anthropogenic stressors.   </p>

scholarly journals Measurement report: Introduction to the HyICE-2018 campaign for measurements of ice nucleating particles in the Hyytiälä boreal forest

2021 ◽  
Author(s):  
Zoé Brasseur ◽  
Dimitri Castarède ◽  
Erik S. Thomson ◽  
Michael P. Adams ◽  
Saskia Drossaart van Dusseldorp ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Ponderosa Pine ◽  
Boreal Forests ◽  
Ice Nucleation ◽  
The Arctic ◽  
Research Station ◽  
Many Sources ◽  
Boreal Environment ◽  
Measurement Infrastructure ◽  
Ponderosa Pine Forest

Abstract. The formation of ice particles in Earth’s atmosphere strongly influences the dynamics and optical properties of clouds and their impacts on the climate system. Ice formation in clouds is often triggered heterogeneously by ice nucleating particles (INPs) that represent a very low number of particles in the atmosphere. To date, many sources of INPs, such as mineral and soil dust, have been investigated and identified in the lower latitudes. Although less is known about the sources of ice nucleation at higher latitudes, efforts have been made to identify the sources of INPs in the Arctic and boreal environments. In this study, we investigate the INP emission potential from high latitude boreal forests. We introduce the HyICE-2018 measurement campaign conducted in the boreal forest of Hyytiälä, Finland between February and June 2018. The campaign utilized the infrastructure of the SMEAR II research station with additional instrumentation for measuring INPs to quantify the concentrations and sources of INPs in the boreal environment. In this contribution, we describe the measurement infrastructure and operating procedures during HyICE-2018 and we report results from specific time periods where INP instruments were run in parallel for inter-comparison purposes. Our results show that the suite of instruments deployed during HyICE-2018 reports consistent results and therefore lays the foundation for forthcoming results to be considered holistically. In addition, we compare the INP concentration we measured to INP parameterizations, and we show a very good agreement with the Tobo et al. (2013) parameterization developed from measurements conducted in a ponderosa pine forest ecosystem in Colorado, USA.

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