Post-fire Period Research Articles

Drivers of Pinus halepensis Plant Community Structure across a Post-Fire Chronosequence

The Pinus halepensis (Aleppo pine) forests prevailing in the western part of the Mediterranean Basin are amongst the most severely affected by fire due to their inherent flammability. Our understanding of the environmental factors driving post-fire community dynamics is currently limited by the lack of time-series data at temporal scales. In this present study, we analyzed a chronosequence of Greek Aleppo pine forests spanning a post-fire period of 65 years. Our goal is to explore the role of post-fire age, altitude, exposure, slope level, parent-rock material, rock cover, and cover of evergreen sclerophyllous shrubs (maquis) on plant assemblage diversity (species richness and Menhinick’s diversity index) and composition. Post-fire age had a significant effect on taxonomic distinctness and community turnover but not on species richness. Taxonomic distinctness increased with post-fire age due to a higher prevalence of the families Fabaceae, Asteraceae, and Poaceae during the early post-fire period. Maquis cover was significantly associated with Menhinick’s diversity index, taxonomic distinctness, and community turnover. Exposure and slope influenced only Menhinick’s diversity index. The turnover in species composition was primarily driven by the geographical proximity of the forests and secondarily by post-fire age and the maquis cover. This highlights the importance of the initial floristic composition in the process of autosuccession after a fire in Mediterranean-climate ecosystems.

Time since fire affects ecological stoichiometry of plant–soil–microbial systems of Betula platyphylla, a pioneer species in burnt areas of China’s boreal forest

Plant stoichiometry and nutrient allocation may reflect adaptation strategies to environmental nutrient changes. Fire, as a major disturbance in forests, mediates soil nutrient availability that may influence plant nutrient dynamics. However, plant–soil stoichiometric allocation strategies during different post-fire periods and the effects of soil, enzymes, and microbial biomass on plant stoichiometry are largely unknown. The pioneer tree species Betula platyphylla in burnt forests of northern China was the object of this study, and severely burned areas selected with different fire years. Nearby unburned areas acted as a control. Carbon (C), nitrogen (N), and phosphorus (P) contents in leaves, branches, and fine roots and rhizosphere soil, C-, N- and P-acquiring enzyme activities were examined. Microbial biomass C, N, and P were measured, and factors influencing C:N:P stoichiometry of plants during the burned area restoration were explored. Our results show that C and N contents in leaves increased with time since fire, while C and P in branches and C, N and P in fine roots decreased. Activities of C-, N-, and P-acquiring enzymes and microbial biomass N increased with time since fire. Redundancy analysis showed that changes in soil N-acquiring enzyme activity, microbial biomass C, and N had significant effects on plant ecological stoichiometry. These results show a significant flexibility in plant nutrient element allocation strategies and C:N:P stoichiometric characteristics. Soil extracellular enzyme activity drives the changes in stoichiometry during the process of post-fire restoration.

Post-fire resurveys reveal predictability of long-term conifer recruitment in severely burned California dry forests

High severity fire is far outpacing post-fire reforestation capacity across the American West, highlighting the need to better understand when and where natural regeneration is sufficient to meet short- and long-term reforestation goals. The vast majority of available post-fire data represents regeneration in the first few years following a fire, raising the question of how well recovery trajectories can be predicted from early post-fire snapshots. We utilize a unique dataset from seven wildfires and 78 plots surveyed twice following stand-replacing fire in two California ecoregions, the northern Sierra Nevada and Klamath Mountains, to ask (1) how are post-fire vegetation and conifer densities changing over time and (2) how well do relatively early post-fire sampling efforts and biophysical factors (availability of seed source, shrub competition, and microclimate) explain longer-term (12–23 year) conifer recovery in California dry forests. Change in conifer seedling density between survey periods was highly variable. Overall, densities of all conifer species during the first decade after fire provided reliable estimates of longer-term conifer recovery in northern California dry forests, though in different ways for different species. Early post-fire seedling density readily explained longer-term densities for less shade-tolerant species, yellow pine (Pinus ponderosa and Pinus jeffreyi) and Douglas-fir (Pseudotsuga menziesii). In contrast, early seedling density was a poor predictor for shade-tolerant species, predominantly white fir (Abies concolor), with site conditions better explaining longer-term density. In general, the probability of a site experiencing net seedling mortality between surveys was highest in sites with high shrub cover and the probability of net recruitment increased with decreasing heat load, suggesting a continued role of microclimate and competition in forest recovery long after the initial post-fire period. Our results lend support to the use of relatively early post-fire surveys to infer longer-term forest recovery trajectories for forest management planning and can help refine reforestation prioritization tools.

Climate limits vegetation green-up more than slope, soil erodibility, and immediate precipitation following high-severity wildfire

BackgroundIn the southwestern United States, post-fire vegetation recovery is increasingly variable in forest burned at high severity. Many factors, including temperature, drought, and erosion, can reduce post-fire vegetation recovery rates. Here, we examined how year-of-fire precipitation variability, topography, and soils influenced post-fire vegetation recovery in the southwestern United States as measured by greenness to determine whether erosion-related factors would have persistent effects in the longer post-fire period. We modeled relationships between post-fire vegetation and these predictors using random forest and examined changes in post-fire normalized burn ratio across fires in Arizona and New Mexico. We incorporated growing season climate to determine if year-of-fire effects were persistent during the subsequent 5 years or if temperature, water deficit, and precipitation in the years following fire were more influential for vegetation greenness. We expected that post-fire factors that drive erosion would reduce greenness; however, these effects would explain less variability in post-fire greenness than growing season climate.ResultsWe found reductions in post-fire greenness in areas burned at high severity when heavy and intense precipitation fell on more erodible soils immediately post-fire. In highly erodible scenarios, when accounting for growing season climate, coefficient of variation for year-of-fire precipitation, total precipitation, and soil erodibility decreased greenness in the fifth year. However, more of the variation in greenness was explained by variability of growing season vapor pressure deficit and growing season precipitation.ConclusionsOur results suggest that while the factors that contribute to post-fire erosion and its effects on vegetation recovery are important, at a regional scale, the majority of the variability in post-fire greenness in high-severity burned areas in southwestern forests is due to climatic drivers such as growing season precipitation and vapor pressure deficit. Given the increasing scale of area burned at high severity and the potential for more post-fire erosion, quantifying how these factors alter ecosystem development is central to understanding how different ecosystem types will be distributed across these landscapes with additional climate change.

Restricted plant diversity limits carbon recapture after wildfire in warming boreal forests

Incomplete wildfire combustion in boreal forests leaves behind legacy plant-soil feedbacks known to restrict plant biodiversity. These restrictions can inhibit carbon recapture after fire by limiting ecosystem transition to vegetation growth patterns that are capable of offsetting warmth-enhanced soil decomposition under climate change. Here, we field-surveyed plant regrowth conditions 2 years after 49 separate, naturally-occurring wildfires spanning the near-entire climatic range of boreal Fennoscandia in order to determine the local to regional scale drivers of early vegetation recovery. Minimal conifer reestablishment was found across a broad range of fire severities, though residual organic soil and plant structure was associated with restricted growth of a variety of more warmth-adapted vegetation, such as broadleaf trees. This dual regeneration limitation coincided with greater concentrations of bacterial decomposers in the soil under increased mean annual temperature, potentially enhancing soil carbon release. These results suggest that large portions of the boreal region are currently at risk of extending postfire periods of net emissions of carbon to the atmosphere under limitations in plant biodiversity generated by wildfire and a changing climate.

The effect of fire on tree-ring width and tracheid dimensions of Pinus nigra

Summary Forest fires play a significant role in the growth and development of trees because they can damage the phloem and cambium. Fire injury induces the formation of fire scars that can cause xylem dysfunction. The study area is located in Taşköprü, Kastamonu (Western Black Sea of Turkiye), where two forest fires occurred in 1957 and 2020. In this study, the effect of the 1957 fire on the tree-ring widths and tracheid dimensions of Pinus nigra trees was investigated. We measured tree-ring widths and tracheid dimensions of fire-scarred (FS) and unscarred (UF) trees during four different periods: the pre-fire period (1947–1956), fire event year (1957), and post–fire periods (1958–1967 and 2011–2020). In this study, UF trees showed almost 2.5–3 times wider tree–ring widths (TRWs) than FS trees. FS and UF trees also showed great variation in tracheid dimensions in the four different periods; the average tracheid diameter (TD), lumen area (TLA), and wall thickness (TWT) values increased significantly in UF trees compared to FS trees during the fire event and post-fire periods. The average TD, TLA, and average tracheid lumen diameter (TLD) decreased during the fire and post-fire years in the FS trees. In this study, we suggest that fire injury significantly affects the tracheid dimensional traits of FS Pinus nigra trees. Our results also suggest that although Pinus nigra trees experienced serious fire damage, they continued to grow but with a decrease in tracheid size.

Qualitative Content Analysis Related to the Use of Instagram @pertamina as a Communication Technology in Response to Post Fire Crisis Plumpang Depo March 2023

On March 3, 2023, a fire occurred at the Pertamina Plumpang Depot, Koja, North Jakarta. Transparency and good communication regarding the responsibilities carried out by Pertamina are important steps in maintaining trust and minimizing the negative impact on the company's reputation. Situational Crisis Communication Theory can be applied in managing communication in crisis situations. The @pertamina Instagram account shows empathy and concern in dealing with the crisis caused by this fire. This article aims to analyze the use of Instagram as a crisis response strategy after the Plumpang Depo fire on March 3, 2023, with a focus on content on the @pertamina account. A qualitative content analysis method was used in this study, with the unit of analysis in the form of content on Instagram @pertamina in the post-fire period at the Plumpang Depo, namely between 4 and 8 March 2023. Data collection was carried out through observing content, including uploads, descriptions on images, and information on the post, and there are ten contents examined. In this study, it was found that Pertamina uses a crisis response strategy model in the form ofdeal response strategy in responding to the crisis. The @pertamina Instagram account is used as a communication technology that becomes a bridge to the public in dealing with crises with consistency and in accordance with society's expectations, such as providing compensation, apologizing, and showing regret, without trying to prove the truth or allude that the crisis originates from factors outside the organization's

Investigation of 2021 wildfire impacts on air quality in southwestern Turkey

In the summer of 2021, unusually intense wildfires happened in southwestern Turkey, especially in Antalya and Mugla with destroying effects on forests, wildlife, and communities residing there. This study aims to understand the air quality impacts of these wildfires. A time period (June–September 2021) covering pre-, fire, and post-periods was investigated using NO2 ground-based observations and TROPOMI CO, HCHO, and NO2 satellite retrievals along with VIIRS FRP. Eight fire regions were selected for detailed analysis in Antalya (An-1-2), Mugla (Mu-1-4), and Mersin (Me-1-2). The highest fire intensity was found in An-1 and followed by Mu-1. CO also showed strongest signals over An-1 (6.73 × 1018 molecules/cm2) with highest levels (1.44 × 1019 molecules/cm2) in the downwind of the wildfires. NO2 showed fire signals in or in very close proximity to the fire regions with strongest signal and largest impact area in An-1 (>8.75 × 1016 molecules/cm2). HCHO showed a different pattern due to HCHO undergoing chemical production and loss in the wildfire plume. HCHO highest levels were not observed over the fire regions, but inside the transported plume with maximum levels for An-1 (3.60 × 1016 molecules/cm2) and for An-2 (3.23 × 1016 molecules/cm2). CO and NO2 increase continued not only in fire, but also in post-fire period, whereas HCHO levels indicated decreases in post-fire compared to pre-fire period. The increases in column concentrations in fire period ranges from 17.6 to 123.1% for CO, 40.6–116.5% for HCHO and 34.4–294.5% for NO2. Higher increases were observed over the Mediterranean Sea especially for CO. Correlations with FRP indicated highest correlations with CO and NO2 and low correlations with HCHO. This study showed that the capability of sparse, ground-level air quality monitoring stations to capture wildfire impacts are limited in the region, because the plume transport was driven by wind direction and wildfire smoke plumes are elevated due to buoyancy. Satellite retrievals are better for capturing the wildfire plume transport and estimating the overall air quality impacts of wildfires.

Sudden water exposure on geared firefighters may cause unexpected burns in post-fire periods

The wetting of fire protective clothing (FPC) is a possibility during fire suppression activities. Hose spraying, inadequate hose usage, accidental water splashes, etc., can be significant water sources which may drastically alter the thermal performance of the FPC. The effect of wetting the FPC outer shell during an exposure scenario on its thermal performance is studied in this numerical study. The exposure scenario considered consists of heat exposure and post-exposure phases, assuming the wetting only happens in the post-fire. Results are discussed relative to when the wetting occurs (i.e., pre-wetting, wetting, and post-wetting phases), identifying the main heat and mass transfer mechanisms responsible for the registered thermal hazards. Second-degree burn times, as well as other thermal performance indicators, are obtained for different wetting times, heat exposure intensities, and outer shell wetting levels. Wetting of the outer shell of an FPC during an exposure scenario can have a highly non-linear effect on second-degree burn occurrence, making it a very challenging phenomenon to consider in the design of FPCs. Firefighters should be warned that any water sprinkling after a fire exposure may cause burns at the most unexpected times during a typical firefighting scenario.

Transformation of peat deposits and carbon accumulation in post-pyrogenic raised bogs within the taiga zone of West Siberia

The aim of the study was to assess of the transformation of the hydrologic and physical properties of peat deposits and peat accumulation rates in the post-pyrogenic sites of drained fens in the taiga zone of West Siberia. Location and time of the study. Field studies were conducted in 2022 on the Bakchar fen (drained for forestry, seven plots) and Ust-Bakchar fen (drained for peat extraction, three plots) located in the Tomsk region. Methods. Peat sampling was carried out from two boreholes at each plot in the hollow and the hummock. The sampling increment was 5 cm; the total depth was 45–90 cm. Peat samples were taken at nine subsites by the envelope method on each plot in 0–30 cm layer by 10 cm increment for water content determination in laboratory. Laboratory study of peat characteristics was carried out using the following methods: water and ash content measurements (GOST 11306-2013, GOST 11306-2013), estimation of peat decomposition and humification degree, botanical composition (GOST 28245-89), as well as measuring peat bulk density. Carbon stocks in the upper layer of peat deposits was estimated using the values of peat ash content and density. Results. The peat deposit of the upper layers was formed mainly by sphagnum peat with Sphagnum fuscum plant residues predominating. The differences between hollows and hummocks in their peat properties were manifested to a depth of 5–15 cm from the surface of depressions. The burnout of the hollows led to the changes of all peat properties to a depth of 10–15 cm: the changes were more pronounced in ash content, which was 1.5–9 times higher in the 0–5 cm layer as compared with the unburned site. The changes in peat properties on positive relief forms, i.e. moss hummocks, was less evident in the upper 0–5 cm layer, but reached a greater depth of 30 cm. The change was revealed mainly as an increase in peat ash content due to the migration of ash elements from the surface of burnt hollows and as an increase in bulk density due to subsidence of moss hummocks with the died-off sphagnum moss. Although the average water content in postpyrogenic and unburned sites was the same, amounting to 90–91% in the 0–30 cm layer, some difference was observed between the microrelief forms. The post-pyrogenic site in the Bakchar fen was characterized by water content decrease in hollows and hummocks, the maximum values being observed at an altitude near the average surface. In the Ust-Bakchar fen, water content was found to decrease from hollows to hummocks. In the Bakchar fen, 30 years after the fire peat accumulation occurred only on positive microrelief forms, where the 35 cm thick layer formed after the fire. Taking into account the microrelief heterogeneity, carbon accumulation over the post-fire period was estimated as 1.9 kg C/m2 or 60 g C/m2 per year. Peat accumulation seemed much slower in the Ust-Bakchar fen and was apparently absent on most of the surface. The average rate was estimated as 7 g C/m2 per year. Conclusions. The study found fen hollows to be most prone to burnout. The consequences of the fire manifest themselves in the drying of the upper layer of the peat deposit, thus preventing intensive overgrowth by sphagnum mosses 6–8 years after the fire. At the drained for forestry site in the Bakchar fen, 30 years after the fire the peat accumulation rate on moss hummocks was comparable to the rate in the unburned areas.

Fire effect on bamboo-dominated forests in Southwestern Amazon: impacts on tree diversity and forest structure

Severe droughts increase the forest flammability, especially if fires are recurrent. Considering that fires tend to alter the forest structure and reduce biological diversity, we analyzed the fire effect on the tree plant community and forest structure over a 10-year post-fire period. The study was carried out in two tropical forest fragments located in the eastern Acre State in southwestern Brazilian Amazon. In each fragment, we established three plots of 250 × 10 m2 in an unburned forest and three in a burned forest. In these plots, we collected all tree individuals with DBH≥10 following the RAINFOR protocol, with censuses made in 2011, 2014, 2016, 2017, 2019, 2020 and 2021. The fire significantly reduced the abundance, basal area, and aboveground biomass of tree species, and altered the species composition along the post-fire temporal gradient. The absence of differences in the species richness and species diversity between unburned and burned forests is probably related to the life cycle of bamboo. The results suggest that, 10 years after the fire, the structure and phytosociology of the forest have not yet fully recovered.

Resilient and regenerative Rural Tourism: the case of Travancinha Village, Portugal

In the recent past, Portugal has suffered from devastating rural fires, particularly in its hinterland regions, with current data on climate change suggesting an increasing risk. This risk jeopardizes these regions’ living conditions, while simultaneously deterring visitors. Still, particularly small-scale, locally embedded rural tourism projects may also help introduce changes in regional landscape management and enhance community resilience. The main goal of this study is to a) analyze the importance of prevention in addressing the challenges imposed by climate change in low-density territories, specifically associated to rural fires in the inland of Portugal, and b) explore how rural tourism can contribute to the resilience and regeneration of the destination after fire-incidents. Based on a qualitative study using a constructive-interpretive case study, namely that of Travancinha village (Municipality of Seia, in Portugal’s Central Region), semi-structured in-depth interviews were conducted with local tourism agents, local authorities, and tourism development agents and subjected to content-analysis. Also, documents and secondary data were analysed, namely statistics and policy documents regarding measures of climate change risk prevention, combat, and mitigation. Based on this, an analysis was performed regarding the pre- and post-fire periods of 2017 and 2022. The results reveal the importance of community collaboration in rural and low-density territories, in the analyzed case, and a model of regenerative tourism, based on community resilience, is proposed. Some conditioning factors for the success of this model are also identified. munidade.

Nonstructural carbohydrates explain post-fire tree mortality and recovery patterns.

Trees use nonstructural carbohydrates (NSCs) to support many functions, including recovery from disturbances. However, NSC's importance for recovery following fire and whether NSC depletion contributes to post-fire delayed mortality are largely unknown. We investigated how fire affects NSCs based on fire-caused injury from a prescribed fire in a young Pinus ponderosa (Lawson & C. Lawson) stand. We assessed crown injury (needle scorch and bud kill) and measured NSCs of needles and inner bark (i.e., secondary phloem) of branches and main stems of trees subject to fire and at an adjacent unburned site. We measured NSCs pre-fire and at six timesteps post-fire (4days-16months). While all trees initially survived the fire, NSC concentrations declined quickly in burned trees relative to unburned controls over the same post-fire period. This decline was strongest for trees that eventually died, but those that survived recovered to unburned levels within 14months post-fire. Two months post-fire, the relationship between crown scorch and NSCs of the main stem inner bark was strongly negative (Adj-R2=0.83). Our results support the importance of NSCs for tree survival and recovery post-fire and suggest that post-fire NSC depletion is in part related to reduced photosynthetic leaf area that subsequently limits carbohydrate availability for maintaining tree function. Crown scorch is a commonly measured metric of tree-level fire severity and is often linked to post-fire tree outcome (i.e., recovery or mortality). Thus, our finding that NSC depletion may be the mechanistic link between the fire-caused injury and tree outcome will help improve models of post-fire tree mortality and forest recovery.

Assessment of forest fire emissions in Uttarakhand State, India, using Open Geospatial data and Google Earth Engine.

In the recent past, forest fires have increased due to the changing climate pattern. It is necessary to analyse and quantify various gaseous emissions so as to mitigate their harmful effects on air pollution. Satellite remote sensing data provides an opportunity to study the greenhouse gases in the atmosphere. The multispectral sensor of the Tropospheric Monitoring Instrument (Sentinel-5) is capable of recording the reflectance of wavelengths vital for measuring the atmospheric concentrations of methane, formaldehyde, aerosol, carbon monoxide, etc., at a spatial resolution of 0.01°. The present study utilized the Google Earth Engine (GEE) platform to study the emissions caused by forest fires in four districts of Uttarakhand State of India, which witnessed unprecedented fires in April-May 2021. All the datasets were ingested in GEE, which has the capability to analyse large datasets without the need to download them. The pre-fire period chosen was September 2020; the fire period was February-May 2021, and the post-fire period was June 2021. The variables chosen were aerosol absorbing index (AAI), carbon monoxide (CO) and nitrogen dioxide (NO2). The climate parameter temperature (Moderate Resolution Imaging Spectroradiometer Land Surface Temperature) and precipitation (from Climate Hazards Group InfraRed Precipitation (CHIRPS) Pentad) were also studied for the period mentioned. The results indicate a different trend for emissions in each district. For AAI, maximum emissions were noted in district Nainital followed by Almora, Tehri Garhwal and Garhwal. For CO emissions, the most affected district was Almora followed by Nainital, Garhwal and Tehri Garhwal. For NO2 emissions, the most affected district was Garhwal, followed by Nainital, Tehri Garhwal and Almora. Delta Normalized Burn Ratio was computed from Sentinel data (difference of pre-fire and post-fire images) to assess the burnt area severity. The Delta Normalized Burn Ratio values observed that the district with the most burnt area is Garhwal, followed by Nainital, Almora and Tehri Garhwal. The elevated temperatures and scanty rainfall patterns regulated the intensity and duration of forest fire. Monitoring the gaseous emissions as a consequence of forest fire in the GEE platform is much easier and more convenient at a regional level. Such data is much needed for mitigation measures to be implemented in time.

Predicting Postfire Sediment Yields of Small Steep Catchments Using Airborne Lidar Differencing

AbstractPredicting sediment yield from recently burned areas remains a challenge but is important for hazard and resource management as wildfire impacts increase. Here we use lidar‐based monitoring of two fires in southern California, USA to study the movement of sediment during pre‐rainfall periods and postfire periods of flooding and debris flows over multiple storm events. Using a data‐driven approach, we examine the relative importance of terrain, vegetation, burn severity, and rainfall amounts through time on sediment yield. We show that incipient fire‐activated dry sediment loading and pre‐fire colluvium were rapidly flushed out by debris flows and floods but continued erosion occurred later in the season from soil erosion and, in ∼9% of catchments, from shallow landslides. Based on these observations, we develop random forest regression models to predict dry ravel and incipient runoff‐driven sediment yield applicable to small steep headwater catchments in southern California.

Arthropod Recolonization of Soil Surface Habitat in Post-Fire Mulch Treatments

Increasing size, severity, and human proximity to fires in the western US are driving a need for more effective ecosystem restoration in the immediate post-fire period. Surface treatments, such as mastication of logging slash, reduce erosion and improve soil nutrient and water retention on steep slopes. However, few studies have investigated the impact of these treatments on arthropod communities over time. Our objective was to determine which insect communities return to these treated areas and if the mulch changes the community structure over time. We surveyed arthropod abundance using pitfall traps in mulch treatments in a landscape-scale fire near Flagstaff, Arizona, and a controlled split-plot experiment outside of the larger fire footprint. Predatory beetles were more abundant in mulch in the large landscape treatment, with no differences in abundance in the split plots. Fungivores had no significant mulch preference, and several native bark beetles were more abundant in the untreated sites. We found that the size of the fire footprint and distance to the intact forest matrix likely impact arthropod community composition over time. We were unable to fully evaluate vegetation recovery, but further work will allow us to understand how surface treatments impact the interaction of arthropods and vegetation.

Peculiarities of the Vital Functions Restoration in Pallas Black Pines Following a Forest Fire

Using the biophysics and visual assessment methods, a study on the vital state dynamics of the Pallas black pine (Pinus nigra subsp. pallasiana D. Don) trees damaged by fire was conducted. It is shown that a ground fire has a noticeable effect on the biophysical characteristics of the Pallas pine. In the post-fire period, there is a change in the electrical resistance of the tree trunk tissues, as well as an increase in its variation coefficient, which reflects the deterioration of their vital condition. The relationship between the parameters of the trunk tissues’ polarization coefficient and the level of the pine trees’ pyrogenic damage was revealed. The intensity of the needles yellowing reflects the amount of stress the trees experience during the pyrogenic impact, it is determined not only by the severity of the impact, but also by the protective response resulting in the mobilisation of the vitality reserves during the post-shock period. The negative effects of stress are manifested in a prolonged decline of the plants’ vital state. Differentiation of the Pallas black pine trees based on the types of response to the damaging impact was revealed. The individuals of an increased regenerative capacity ensure the group preservation under a strong short-term negative impact. Individuals with a weak response realise their advantage in a situation of a lingering stress, conservatively utilising their vitality reserves, which ensures the possibility of long-term survival under inhospitable conditions. Currently, the natural populations of Pallas black pine, are forming “scissors” of two evolutionarily different natural selection tendencies. Under the lingering stressful conditions, individuals with weaker reaction are more likely to survive and the elimination of individuals with a strong response to stress increases, which entails a decrease in the resistance of populations to a strong destructive effect.

Динамика напочвенного покрова в биотопах сосновых лесов при фрагментации, вызванной пожарами, в условиях лесостепной зоны

The ground cover in the forest plant community is the most dynamic structure. We analyzed the ground cover in the pre- and post-fire period in the forest community of a pine forest of natural origin, not damaged by fires, but located on the border of the harem. The study was carried out in biotopes of pine forest (Voronezh region, Educational and Experimental Forestry Enterprise of Voronezh State Forestry Engineering University named after G.F. Morozov) by describing the ground cover of the transect in several types of forest of areas undamaged by fire: dry forest, raw forest, subor. Over the past decade, the total number of ground cover species in the pine forest has been preserved (63 species), their species composition is changing. The greatest species diversity is characteristic of suborea. By 2022, steppe and meadow plants, primarily cereals, will appear in the flora, which indicates a change in environmental conditions. Ground lichens have completely disappeared, as well as 19 species of indicator plants, six of which are included in the Red Book of the Voronezh Region. There was a change in the structure of plant groups. Along with the indicator species, meadow and steppe species appear in the groups. The total projective coverage of the ground cover decreased from 80 to 68 %, as well as the projective coverage of the thicket (from 60 to 50%), mosses (from 80 to 70%), lingonberries (from 40 to 30%) in groups.

Physical and biogeochemical drivers of solute mobilization and flux through the critical zone after wildfire

A nine-year time series of nutrient cation and anion concentration and efflux from three forested catchments in the Jemez River Basin Critical Zone Observatory (JRB-CZO) in northern New Mexico was used to quantify the pulse of chemical denudation resulting from varying levels stand-replacing wildfire intensity in May-June of 2013. The 3 years of pre-fire and 6 years of postfire data were also probed to shed light on the mechanisms underlying the pulsed release and the subsequent recovery. The initial large solute pulse released to the streams—K+, Ca2+, Mg2+, SO42-, Cl−, dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), and total dissolved nitrogen (TDN)—was caused by leaching of hillslope ash deposits during the first monsoon storms post-fire. Debris flow following the wildfire likely redistributed much of the ash-containing sediments along streams and valley bottoms. Sustained elevated solute concentrations observed in the surface waters throughout the post-fire period relative to pre-fire baselines is consistent with these soluble materials being periodically flushed from the soils during wet seasons, i.e., snowmelt and summer monsoons. As microbial mediated reactions and biotic uptake—due to plant regrowth—recover after fire, nutrient ion export (e.g., NO3-, Cl− and SO42-) steadily decreased toward the end of the post fire period, but remained above pre-fire levels, particularly for NO3- and SO42-. Surface water concentrations of polyvalent cations (e.g., Al and Fe) decreased significantly after the fire. Our observations suggest that changes in organic matter composition after fire (e.g., increased humification index—HIX) and the presence of pyrogenic carbon may not favor organo-metal complexation and transport. Finally, differences in burn severity among the three watersheds presented in this study, provide insights of the relative impact of solute exports and resilience. The catchments that experienced high burn severity exhibited greater solute fluxes than the less severely burn. Moreover, despite these differences, toward the end of the post-fire period these surface waters presented low and similar solute effluxes, indicating system recovery. Nonetheless, magnitudes and rebounds were solute and process specific. The results of this study highlight the importance of surface and near surface physical and biogeochemical processes on the long-lasting geochemical denudation of forested catchments following wildfires of varying intensities.

Modelling of the fire impact on CONSTOR RBMK-1500 cask thermal behavior in the open interim storage site

Spent nuclear fuel and long-lived radioactive waste must be carefully handled before disposing them off to a geological repository. After the pre-storage period in water pools, spent nuclear fuel is stored in casks, which are widely used for interim storage. Interim storage in casks is very important part in the whole cycle of nuclear energy generation. This paper presents the results of the numerical study that was performed to evaluate the thermal behavior of a metal-concrete CONSTOR RBMK–1500 cask loaded with spent nuclear fuel and placed in an open type interim storage facility which is under fire conditions (steady-state, fire, post-fire). The modelling was performed using the ANSYS Fluent code. Also, a local sensitivity analysis of thermal parameters on temperature variation was performed. The analysis demonstrated that the maximum increase in the fuel load temperatures is about 10 °C and 8 °C for 30 min 800 °C and 60 min 600 °C fires respectively. Therefore, during the fire and the post-fire periods, the fuel load temperatures did not exceed the 300°C limiting temperature set for an RBMK SNF cladding for long-term storage. This ensures that fire accident does not cause overheating of fuel rods in a cask.