Глубина прогорания торфа и потери углерода при лесном подземном пожаре

Among forest fires, underground (peat) fires lead in terms of the amount of material burned per unit area and, consequently, the impact on climate change, but they differ in the complexity of assessing the loss of soil carbon and its emissions to the atmosphere. Using the example of the 2010 forest and peat fire in Moscow oblast (an area of 9 ha with a variable original tree-stand composition), the depth of burnout and loss of soil carbon were determined by reconstructing the prefire soil surface along the root collar of stumps, as well as comparing the characteristics of peat on the burned and adjacent areas. The average (median) burnout depth was 15 ± 8 (14) cm, varying in different areas from 13 ± 5 (11) to 20 ± 9 (19) cm. The burnout depth increased with the relative surface height and was maximum in areas with a predominance of aspen. Based on the data of the layer-by-layer determination of the bulk density, ash content, and carbon content in peat, the dependences of the carbon stock on the peat thickness are obtained. Based on them, and according the depth of burning, the carbon losses are estimated, which amount to an average (median) of 9.8 ± 5.57 (9.22) kg m–2 for the burned-out areas, varying in different areas from 8.61 ± 3.75 (7.39) to 12.9 ± 6.18 (12.3) kg m–2, which is equivalent to a one-time emission of almost 400 t СО2 ha—1 and at least 1.5 times higher than the possible release of CO2 into the atmosphere from the loss of carbon biomass of a growing stand with a stem wood stock of more than 280 m3 ha–1. The results correspond to the upper limit of estimates of soil carbon losses obtained by foreign authors and confirm the underestimation of the factor of underground (peat) fires in the boreal zone in comparison with the tropics and in general when considering the influence of forest and peatland ecosystems on the gas composition of the atmosphere and climate.

Identification of peat-fire-burnt areas among other wildfires using the peat fire index

Peat fires differ from other wildfires in their duration, carbon losses, emissions of greenhouse gases and highly hazardous products of combustion and other environmental impacts. Moreover, it is difficult to identify peat fires using ground-based methods and to distinguish peat fires from forest fires and other wildfires by remote sensing. Using the example of catastrophic fires in July–August 2010 in the Moscow region (the center of European Russia), in the present study, we consider the results of peat-fire detection using Terra/Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) hotspots, peat maps, and analysis of land cover pre- and post-fire according to Landsat-5 TM data. A comparison of specific (for detecting fires) and non-specific vegetation indices showed the difference index ΔNDMI (pre- and post-fire normalized difference moisture Index) to be the most effective for detecting burns in peatlands according to Landsat-5 TM data. In combination with classification (both unsupervised and supervised), this index offered 95% accuracy (by ground verification) in identifying burnt areas in peatlands. At the same time, most peatland fires were not detected by Terra/Aqua MODIS data. A comparison of peatland and other wildfires showed the clearest differences between them in terms of duration and the maximum value of the fire radiation power index. The present results may help in identifying peat (underground) fires and their burnt areas, as well as accounting for carbon losses and greenhouse gas emissions.

Peat fires in tropical peatland release a substantial amount of carbon into the environment and cause significant harm to peatlands and the ecology, resulting in climate change, biodiversity loss, and the alteration of the ecosystem. It is essential to understand peat fires and to develop more effective methods for controlling them. To estimate carbon emissions and monitor fires, the depth of burning can measure the overall burnt down the volume, which is proportional to the carbon emissions that are emitted to the environment. The first step is to understand the technique of measuring the depth of the burn. However, there is a lack of integrated information regarding the burning depth for peat fires. This review paper discusses the techniques used to measure the burning depth, with particular attention given to quantifying carbon emissions. The article also provides information on the types of methods used to determine the burning depths. This research contributes to the field of peat fire by providing a readily available reference for practitioners and researchers on the current state of knowledge on peat fire monitoring systems.

Introduction. The paper considers the influence of radiation forest and peat fires on the spread of radioactive contamination, which affects the well-being of thousands of people. The state of the environment in vast territories is deteriorating; negative socio-economic processes are developing. This is a serious problem of two states: the Russian Federation and the Republic of Belarus. The objectives of the presented work are to study the radiation situation in forests and peat bogs located in the border areas of the Bryansk region, as well as to study the possibility of transferring radioactive materials during forest and peat fires. Materials and Methods. The facts that clarified the theoretical basis of the presented research are highlighted in the scientific literature. The authors took into account, in particular, that: – the activity of radionuclides in the soil decreases in direct proportion to the depth; – a peat fire is an uncontrolled burning; – emissions of caesium-137 fractions (137Cs) during a fire can reach 3–4 %. We know the areas of forests in radiation-contaminated territories (RCT) of the Bryansk region from the applied literature and official sources. The most problematic areas from this point of view have been identified.A mobile radiometric laboratory, a scintillation gamma-ray spectrometer MKS-AT6101S were involved in the expedition research. The results of field gamma-ray spectrometry were recorded in three localities. The calculations for a hypothetical fire were carried out using the SAUR AIUS RSCHS 2030 software tool. Results. The consequences of large and prolonged fires in the exclusion zone of the Chernobyl nuclear power plant are analyzed. It is established that the incidents did not lead to dangerous consequences for the population. The total effective dose of inhalations was ~0.003 % of the permissible level of irradiation. It is noted, however, that the forest soil of the Bryansk region has received significant damage from 137Cs pollution. The density of such pollution exceeded 5 Ci/km2 in 40 % of the affected forests. Of these, an indicator of 15-40 Ci/km2 and more was recorded in 16 %, in some quarters — up to 200 Ci/km2. It is established that zones with a high contamination density (40 Ci/km2) will remain in the region until 2026. Five districts are particularly problematic: Gordeevsky, Zlynkovsky, Klintsovsky, Krasnogorsky and Novozybkovsky. When fixing and predicting harm, the authors of the presented work proceeded from the following fact: during fires, the combustion products (forest litter, grass and undergrowth) contain more radioactive substances than the crowns of trees. In this regard, measurements were not made at a significant height. The field study route was chosen based on the available data on the maximum level of radioactive contamination. The ambient dose equivalent rate (ADER) of gamma radiation recorded at 2,757 points did not exceed 1.2 μSv/h (with an average value of 0.2-0.3 μSv/h). Measurements in the marshes did not reveal traces of 137Cs at a depth of more than 40 cm. The maximum activity of 137Cs was observed in the upper (0–4 cm) soil layer (up to 65 %). Taking into account the data obtained, the possibility of radioactive containation in the event of a forest fire was assessed. According to the calculations in the software environment, radioactive contamination will spread to 348 hectares. The density of radioactive contamination of the area may increase by 5–10 % (from the initial one). 33 people will suffer; there is a threat of death of 1 person. It has been established that a burning peat bog is the most powerful and long-term source of radioactive contamination, therefore it is important to prevent peat and forest fires. This will reduce the transfer of radionuclides and emissions of radioactive fumes. Remote and surface radiation monitoring facilities should be developed. Discussion and Conclusion. The registered ADER is not dangerous for the health of the population of the Bryansk region. However, frequent fires significantly increase the likelihood of transferring active 137Cs to residential areas. In this sense, timely monitoring and forecasting of fires is relevant. The authors formulated proposals to improve the technical and technological components of the solution of the considered problem. 1. To clarify the radiation situation, all-terrain vehicles should be equipped with: – means of registering the radiation situation; – software and hardware complex for automatic collection, analysis of information and its fixation in databases. 2. There should be a reliable cellular communication between all rapid response units in the emergency zone. Further research is focused on the creation of fast-deployable radiation monitoring modules and mobile aerial photography complexes using drones in the emergency zone.

Peat fires differ from other wildfires by significant carbon loss, the emission of greenhouse gases and other combustion products as well as by serious environmental consequences. Not only biomass but also peat is burnt. A possibility of detecting peat fires from satellite and ground-based data is considered for the fires in the Moscow region in 2010. The peat fire detection technique was tested by superimposing data on thermal anomalies from Terra/Aqua MODIS satellite data on the peatland contours, as well as by analyzing the vegetation cover changes before fires and the next year using the Landsat satellite multispectral data. Threshold values were found for the fire duration, maximum temperature, and maximum fire radiative power that characterize peat fires and can be used to discriminate between fires on peat lands and peat fires themselves for taking into account emissions not only from biomass burning but also from soil carbon loss.

Quantifying soil carbon loss and uncertainty from a peatland wildfire using multi-temporal LiDAR

Carbon loss and emissions within a permafrost collapse chronosequence

Underground peat fires are a major hazard to health and livelihoods in Indonesia, and are a major contributor to carbon emissions globally. Being subterranean, these fires can be difficult to detect and track, especially during periods of thick haze and in areas with limited accessibility. Thermal infrared detectors mounted on drones present a potential solution to detecting and managing underground fires, as they allow large areas to be surveyed quickly from above and can detect the heat transferred to the surface above a fire. We present a pilot study in which we show that underground peat fires can indeed be detected in this way. We also show that a simple temperature thresholding algorithm can be used to automatically detect them. We investigate how different thermal cameras and drone flying strategies may be used to reliably detect underground fires and survey fire-prone areas. We conclude that thermal equipped drones are potentially a very powerful tool for surveying for fires and firefighting. However, more investigation is still needed into their use in real-life fire detection and firefighting scenarios.

Anthropogenic activities and climate change are increasing the vulnerability of carbon rich peatlands to wildfires. Peat fires, which are dominated by smouldering combustion, are some of the largest and most persistent wildfires on Earth. Across the northern high latitudes, peat fires have the potential to release vast amounts of long term stored carbon and other greenhouse gases and aerosols. Consequently, peat fires can have huge implications on the carbon cycle and result in a positive feedback effect on the climate system. Peat fires also impact air quality and can lead to haze events, with major impacts on human health. Despite the importance of peat fires they are currently not represented in most fire models, leading to large underestimations of burnt area and carbon emissions in the high latitudes. Here, I present a representation of peat fires in the JULES-INFERNO fire model (INFERNO-peat). INFERNO-peat improves the representation of burnt area across the high latitudes, with notable areas of improvement in Canada and Siberia. INFERNO-peat also highlights a large amount of interannual variability in carbon emissions from peat fires. The inclusion of peat fires into JULES-INFERNO demonstrates the importance of representing peat fires in models, and not doing so may heavily restrict our ability to model present and future fires and their impacts across the northern high latitudes.

Peat fires smoulder for long periods (weeks to months) and releasing large amount of ancient carbon that have been stored for millennia in the organic soils. Recent wildfires in Arctic regions have burned unprecedented swaths of land, demonstrating a detrimental change in the arctic fire regime and highlighting the vulnerability of these biomes to climate change. This work aims to experimentally study Arctic peat fires in the lab scale by using an experimental rig with adjustable air temperature and bottom boundary of the peat fire which imitate the condition of permafrost in the Arctic. The initial temperature of the peat sample varied from -13 to 18°C, and the moisture content (MC) was varied from 50 to 120% in dry-mass basis. The experimental results show that smouldering can be sustained with soil temperatures below the freezing point of water. The range of condition temperature in this study was found to insignificantly affect spread rate but have profound effect on the depth of burn, increasing by up to 66% as bottom boundary decreased from 21 to -7°C. We found that the critical moisture content of ignition under cold condition in this work is between 110 and 120% (dry-mass basis), and is lower than the literature in room temperature (160%). At high moisture content (≥100% MC), smouldering was weakly spreading under air temperature of ~12°C, initial peat temperature of -11°C, and bottom boundary of -7°C. However, spread rate significantly increased as the air and bottom boundary temperatures were increased to 22°C, demonstrating overwintering fires which often found in the Arctic when peat fires were considered to be extinguished only to resurface when warmer season arrives. This study is the first experimental work on smouldering Arctic wildfires with findings that can improve our understanding on the effect of cold temperatures on the smouldering dynamics of peat fires, and presents a novel methodology to investigate Arctic fires at laboratory scale.

In recent years, large wildfires have spread in Arctic regions as a consequence of ongoing climate change. Arctic organic soils are comparatively shallow but may be ancient, thus thousands of years old carbon may be released in smoldering and deeply burning fires. In Greenland, a land known for its icy expanse, fires are extremely rare. However, in summer 2019, the second-largest wildfire ever recorded on the island occurred at the Kangerluarsuk Tulleq fjord in southwestern Greenland. This study aims to produce pioneering in-field data on this tundra fire, focusing on three key aspects: 1) combustion, 2) burn depth, and 3) the age of the carbon released. Understanding whether the released carbon is modern or old is crucial due to different implications for the global carbon cycle and climate. To estimate carbon losses from the Kangerluarsuk Tulleq tundra fire, we established 14 sampling plots in burned areas and at unburned control sites. The selection of sampling plots was guided by a differenced Normalized Burn Ratio (dNBR) map generated using Sentinel-2 data and field reconnaissance. Within each plot, we assessed fire severity to estimate the above-ground carbon loss. For below-ground carbon loss estimation and burn depth analysis, organic soil samples were collected at burned plots and compared with unburned ones. To explore the vegetation succession and burned vegetation type, organic soil profiles (n=10) were extracted down to the mineral ground using a soil box corer and were studied by light-microscopy. Subsamples (n=20) from burned soil horizons were selected for radiocarbon dating to determine the age of carbon released in the fire. Our preliminary results suggest that soil carbon loss was higher than previously reported at an Alaskan tundra fire site with a mean value of 6.718 ± 0.9 kg of C m-2. The mean burn depth was 9.0 ± 1.8 cm, and soil thaw depths during the 2024 summer were approximately 24 cm deeper in the 2019 burned area compared to unburned tundra. Expected radiocarbon results will indicate the maximum age of the carbon released by the fire. Vegetation succession measurements show that post-fire surfaces were predominantly colonized by pioneering non-Sphagnum bryophytes, Cyperaceae, and Ericaceae. The acquired results are first of a kind from a Greenland tundra fire and produce essential data for global climate modeling to assess the climate impacts of increasing Arctic wildfires.

The effects of surface (aboveground) and peat (belowground) fire on a number of soil constituents were examined within a hydrologically altered marsh in the northern Florida Everglades. Peat fire resulted in losses of total carbon (TC), total nitrogen (TN), and organic phosphorus (Po), while inorganic phosphorus (Pi) and total calcium (TCa) concentrations increased. In addition, peat fire led to a more pronounced vertical gradient in constituent concentrations between upper and lower soil layers. Surface fire also affected soil constituents, but impacts were small relative to peat fire. The effects of physical versus chemical processes during burning were assessed using ratios of constituent to TCa concentrations. This measure indicated that increases in the levels of total phosphorus (TP) in peat-burned areas were due primarily to the physical reduction of soil, while decreases in TN and TC were the result of volatilization. Increases in concentrations of Pi fractions arose from both chemically and physically mediated processes. In an ecological context, the observed soil transformations may encourage the growth of invasive plant species, such as southern narrow-leaved cattail (Typha domingensis Pers.), which exhibits high growth rates in response to increased P availability.

Peat fire emits a large amount of carbon to the atmosphere. This emission can affect atmospheric composition and also the climate system. This paper discussed the carbon emission from the 2015 peat fire, the largest after 1997 one. Indonesian National Carbon Accounting System (INCAS) published by The Indonesian Ministry of Environment and Forestry was used to calculate the carbon emission from the peat fire. Peat fire emission factors used in the calculation for region of Sumatera and Kalimantan were selected from previous study, while for Papua’s region extrapolation method was applied. Peat area burned was estimated by using Normalized Burn Ratio (NBR) based on hotspot data enquired from MODIS. The cumulative peatland area burned from July – October 2015 in Indonesia was estimated to be about 623,304 ha, where about 270,691 ha (43%), 320,756 ha (51%) and 31,857 ha (5%) were found in Sumatera, Kalimantan and Papua, respectively. By considering only the three biggest gaseous carbon compounds released by biomass burning (CO2, CO, and CH4), therefore total carbon emitted to the atmosphere during these four months peat fire was estimated to be about 0.002 Gtonnes, of which 81% was in the form of CO2; 16% CO and 2.3% CH4.

Can rain suppress smoldering peat fire?