Fire Distribution Research Articles

The landscape genetics of a mass-flowering fire-ephemeral plant.

Obligate fire ephemerals are annual plants that have germination and reproduction cued by fire occurrence, persisting between fire events in a long-lived soil seed bank. Within these species, gene flow is restricted not only geographically but also temporally because individuals are limited to reproducing with others affected by the same fire event. The patchwork-like distribution of fires may therefore promote population isolation. In contrast to past fires, the Australian fires of 2019-2020 were of unprecedented extent, providing an opportunity to investigate the landscape genetics of a fire ephemeral, Actinotus forsythii, across multiple populations and to compare it to a common congener, Actinotus helianthi. For both species, we used single nucleotide polymorphisms to infer patterns of population structure and calculate measures of genetic diversity. We also estimated a phylogeny of Actinotus forsythii to understand the differentiation of a geographically isolated population. For A. forsythii, the within-population diversity (allelic richness = 1.56) was greater, and the among-population differentiation (FST = 0.30) was lower than that observed for A. helianthi (allelic richness = 1.33, FST = 0.57). Actinotus forsythii had distinct geographic groupings, and a geographically isolated population of this species was genetically highly differentiated. Despite the fire-dependent, asynchronous gene flow, predicted between site disconnect, and possible within-site homogeneity, our results suggest that burn mosaic could be influencing gene flow patterns and fire-triggered mass flowering may promote genetic diversity within Actinotus forsythii.

Study on the Driving Factors of the Spatiotemporal Pattern in Forest Lightning Fires and 3D Fire Simulation Based on Cellular Automata

Lightning-induced forest fires frequently inflict substantial damage on forest ecosystems, with the Daxing’anling region in northern China recognized as a high-incidence region for such phenomena. To elucidate the occurrence patterns of forest fires caused by lightning and to prevent such fires, this study employs a multifaceted approach, including statistical analysis, kernel density estimation, and spatial autocorrelation analysis, to conduct a comprehensive examination of the spatiotemporal distribution patterns of lightning-induced forest fires in the Greater Khingan Mountains region from 2016–2020. Additionally, the geographical detector method is utilized to assess the explanatory power of three main factors: climate, topography, and fuel characteristics associated with these fires, encompassing both univariate and interaction detections. Furthermore, a mixed-methods approach is adopted, integrating the Zhengfei Wang model with a three-dimensional cellular automaton to simulate the spread of lightning-induced forest fire events, which is further validated through rigorous quantitative verification. The principal findings are as follows: (1) Spatiotemporal Distribution of Lightning-Induced Forest Fires: Interannual variability reveals pronounced fluctuations in the incidence of lightning-induced forest fires. The monthly concentration of incidents is most significant in May, July, and August, demonstrating an upward trajectory. In terms of temporal distribution, fire occurrences are predominantly concentrated between 1:00 PM and 5:00 PM, conforming to a normal distribution pattern. Spatially, higher incidences of fires are observed in the western and northwestern regions, while the eastern and southeastern areas exhibit reduced rates. At the township level, significant spatial autocorrelation indicates that Xing’an Town represents a prominent hotspot (p = 0.001), whereas Oupu Town is identified as a significant cold spot (p = 0.05). (2) Determinants of the Spatiotemporal Distribution of Lightning-Induced Forest Fires: The spatiotemporal distribution of lightning-induced forest fires is influenced by a multitude of factors. Univariate analysis reveals that the explanatory power of these factors varies significantly, with climatic factors exerting the most substantial influence, followed by topographic and fuel characteristics. Interaction factor analysis indicates that the interactive effects of climatic variables are notably more pronounced than those of fuel and topographical factors. (3) Three-Dimensional Cellular Automaton Fire Simulation Based on the Zhengfei Wang Model: This investigation integrates the fire spread principles from the Zhengfei Wang model into a three-dimensional cellular automaton framework to simulate the dynamic behavior of lightning-induced forest fires. Through quantitative validation against empirical fire events, the model demonstrates an accuracy rate of 83.54% in forecasting the affected fire zones.

Estimation and research of the temperature field models of large space spherical mesh shell structures under localized fire

This paper firstly investigated fire dynamics characteristics and the temperature field distributions of large space spherical mesh shell (SMS) structures under localized fire in FDS, and divided the temperature fields into plume region, smoke accumulation region and ceiling jet region. Based on the classical axisymmetric plume model, the predictive models for the steady-state and transient temperature fields in different fire regions for large space SMS structures were proposed in this paper. Thereafter, the proposed temperature models were compared with the simulated results and experimental test results by other scholars, and they were in good agreement. In order to further discover the realistic fire development progress and temperature distribution of large space fire, and validate the proposed temperature field models, this paper designed and conducted three full-scale large space fire tests (Test-1 ∼ Test-3) with different fire source powers in a large space building. Results showed that temperature fields of large space fires could be consisted of near-fire region (Flame region) and far-fire region (Plume region and Ceiling jet region). The steady-state fire source powers were tested for 443 kW, 886 kW, 1090 kW for Test-1, Test-2 and Test-3, respectively, while their maximum temperatures of the roof reached 75 °C, 105 °C and 120 °C. Based on McCaffrey plume model, we further proposed the transient temperature model in flame region for large space structures, and its accuracy was verified by the test results. Moreover, the proposed steady-state and transient temperature fields for large space SMS structures were compared with the tested temperature field data, and the tested and predicted temperature curves were generally in good agreement in plume and ceiling jet regions. Finally, the test results aimed to provide a scientific basis and reference for the fire safety and structural fire-resistant design of large space buildings.

Smoke control and temperature distribution of tunnel fires under longitudinal ventilation combined with shaft exhaust

Longitudinal segmental smoke exhaust is often used for fire tunnels longer than 5 km. With the combined effect of longitudinal ventilation in the main tunnel and fan suction in the exhaust shaft, the smoke exhaust path is different from that of a traditional single-tube tunnel. Findings reported in the literature is insufficient to support the rapid development of extra-long road tunnels. In this paper, a numerical model was established by FDS (Fire Dynamics Simulator), and a 1:15 model test platform was built for verification. The effects of different longitudinal velocities, exhaust velocities, bifurcation angles, and exhaust shaft slopes on tunnel fires were analyzed for the longitudinal ventilation combined with shaft exhaust smoke evacuation mode (LVSE). The results show that when the exhaust velocity is greater than 4.5m/s, increasing the exhaust velocity has a limited effect on reducing the smoke length downstream of the exhaust shaft. The bifurcation angle has a significant effect on the velocity distribution in the ventilation shaft and the main tunnel. When the bifurcation angle is less than 45°, the airflow in the main tunnel is more likely to enter the exhaust shaft, and the velocity in the exhaust shaft is more than 5m/s. It is more favorable to reduce the smoke length when the slope of the exhaust shaft is not less than 7%. The high-temperature flue gas collects and forms a vortex near the vent under the LVSE mode, which makes the temperature decay rate slower than that when only longitudinal ventilation is used. The temperature decay model for the LVSE mode is obtained. This study is intended to provide a reference basis for the fire safety design of extra-long road tunnels under the LVSE mode.

Construction and assessment of a fire risk index system for typical grasslands in Xinjiang, China

BackgroundFire hazards have a substantial impact on grassland ecosystems, and they are becoming more frequent and widespread because of global changes and human activities. However, there is still a lack of a widely accepted or practical method to evaluate grassland fire risk. In our study of typical grasslands in northern Xinjiang, we selected 18 evaluation indicators for grassland fires from three aspects of hazard, exposure, and vulnerability. Employing the analytic hierarchy process, weighted comprehensive evaluation method, and standard deviation classification, we determined the fire risk level thresholds, aiming to develop efficient and precise methods for assessing grassland fire risks, and ultimately created a grid-based map of grassland fire risk levels.ResultsThe risk level of grassland fires is determined by the combined spatial heterogeneity of fire-causing factors’ hazard and fire hazard-bearing bodies’ vulnerability and exposure. The hazard of grassland fire and fire hazard-bearing bodies’ vulnerability and exposure are dominated by medium level and medium–low level. Most areas of grassland fire risk levels are medium–low, medium, or medium–high risk, with few areas being high risk or low risk. The grassland fire risk exhibits a spatial distribution characterized by higher risks in the western and lower in the eastern; high and medium–high risk areas are primarily distributed in the western and some northeastern regions of the study area. The simulate result effectively represents the spatial distribution of grassland fire in the research area.ConclusionWe established a grassland fire risk index system and model, creating a spatial distribution map of grassland fire risk levels based on grid. Few grassland areas have fire risks and show a patchy distribution. The results generally reflect the spatial distribution pattern of grassland fire risks in the study area. This research provides technical support for scientifically formulating local grassland fire disaster prevention and relief strategies.

Flame Geometry and Temperature Distribution of Jet Fires in Pits

Flame Geometry and Temperature Distribution of Jet Fires in Pits

Experimental study on the effect of longitudinal ventilation on spill fire characteristics in sloped tunnels

A series of spill fire tests were carried out in a reduced-scale tunnel (6 m × 0.6 m × 0.45 m), considering different discharge rates (60–140 ml/min), ventilation rates (0∼1.26 m/s), and tunnel slopes (3 %, 5 %, 7 %). Some crucial characteristic parameters during the quasi-steady combustion stage of tunnel spill fires were analyzed, including the diffusion shape of the liquid fuel, mass burning rate per unit area, flame morphology and plume temperature, and the critical ventilation velocity. The results show that as the tunnel slope increases, the diffusion shape of the liquid fuel transitions from circular to an ellipse shape and then to rectangular or linear shape. Moreover, the mass burning rate per unit area decreases with increasing ventilation rates at low ventilation (V < 0.5 m/s), while it remains almost constant at high ventilation rates (V ≥ 0.5 m/s). This could be attributed to variations in flame tilt behavior under different ventilation conditions. Predictive models for the flame tilt angle and the vertical temperature distribution of tunnel spill fires under the effect of ventilation were further established and verified. Furthermore, the critical ventilation velocity of tunnel spill fires remains essentially unchanged as the discharge rate (or fire source power) increases. This phenomenon was explained by analyzing the resistance of the spill fire plume and the buoyancy generated by the smoke temperature. This work could serve as a critical reference for assessing disaster risks and executing emergency rescue operations during tunnel spill fires.

Numerical simulation of high-pressure jet fire in on-board hydrogen storage cylinders under fire conditions

Hydrogen fuel cell vehicles (HFCVs) may cause fires in the event of an accident. When the high-pressure hydrogen storage cylinders are exposed to fire for a long time, there will be a risk of catastrophic consequences such as leakage, jet fire and explosion. Fire test is the main method to study the safety performance of hydrogen storage cylinders. During the firing process, the wall and internal temperature of the hydrogen storage cylinder rise gradually, and the thermally activated pressure relief device (TPRD) of the cylinder reaches a certain temperature and then releases high-pressure hydrogen to prevent the cylinder from bursting. As the hydrogen storage cylinder is in the fire environment, the release of high-pressure hydrogen will be ignited to form a jet fire and cause damage to personnel and equipment. In this paper, CFD software Fluent was used to numerically simulate the local fire test of the hydrogen storage cylinder with high-temperature air as the fire source. The variation law of cylinder wall temperature, gas temperature and pressure inside the cylinder, and the activation of TPRD were analyzed. At the same time, on the basis of the fire test simulation, a high-pressure hydrogen jet fire simulation numerical model caused by the TPRD action was established. The velocity field, temperature field and hydrogen concentration distribution of the jet fire were obtained, and the overpressure generated by the jet fire and the flame length size were analyzed. The results show that the high-pressure hydrogen released by TPRD was ignited under the fire condition to produce a jet flame and generated an overpressure in the jet direction, and the influence range of the overpressure was smaller than the influence range of the jet flame.

Assessing four decades of fire behavior dynamics in the Cerrado biome (1985 to 2022)

BackgroundFire significantly transforms ecology and landscapes worldwide, impacting carbon cycling, species interactions, and ecosystem functions. In the Brazilian Cerrado, a fire-dependent savanna, the interaction between fire, society, and the environment is evident. Given that wildfires significantly contribute to greenhouse gas emissions, our study aimed to analyze four decades of burned area data to understand changes in fire dynamics, using Collection 2 of annual MapBiomas Fire maps (1985 to 2022). Our study examined spatiotemporal patterns, fire recurrence, fire distribution across land uses, temporal changes in fire scar size, burned area variations across ecoregions, and their correlation with farming areas.ResultsFrom 1985 to 2022, fire impacted 40% (792,204 km2) of the Cerrado biome, with 63% burning more than once. Natural vegetation was the most affected, primarily due to human-driven ignition during the dry season. A noticeable trend of later peaks in fire activity, concentrated towards the end of the dry season, along with an increase in patch size over time, characterized a clear shift in the Cerrado fire regime. Recently, the MATOPIBA region and the northern biome exhibited significant fire clusters, with burned areas rising alongside farming expansion. The ecoregion-based analysis identified fire hotspots, with the "Bananal" ecoregion, the largest wetland area in the biome, exhibiting increased fire recurrence and larger patch size over time.ConclusionsOur four-decade analysis of fire dynamics in the Cerrado revealed human-induced changes in the fire regime, originally shifting from July to September to a new fire season from August to October. This shift poses several environmental threats given their overlap with the driest months of the year. This study improved our understanding of changes in fire patterns and their impacts on each ecoregion and land use. Wetlands experienced the highest relative burned area, highlighting their ecological importance and increased vulnerability. In the southern Cerrado, where farming is established and natural vegetation more fragmented, fire events tend to decrease; while in the north, with recent farming expansion, fire susceptibility rises. Conservation-oriented strategies, like the Brazilian Integrated Fire Management (MIF), are crucial for mitigating impacts while enhancing the Cerrado’s resilience to climate change.

Spatio-Temporal Analysis of Wildfire Regimes in Miombo of the LevasFlor Forest Concession, Central Mozambique

Wildfires are an intrinsic and vital driving factor in the Miombo ecosystem. Understanding fire regimes in Miombo is crucial for its ecological sustainability. Miombo is dominant in Central Mozambique, having one of the highest fire incidences in the country. This study evaluated the spatio-temporal patterns of fire regimes (intensity, seasonality, frequency and fire return interval) in the LevasFlor Forest Concession (LFC), Central Mozambique using remotely sensed data from 2001 to 2022. We conducted hotspot spatial statistics using the Getis-Ord Gi* method to assess fire distribution and patterns. The results revealed that 88% of the study area was burnt at least once from 2001 to 2022, with an average burned area of 9733 ha/year (21% of LFC’s total area). Fires were more likely to occur (74.4%) in open and deciduous Miombo types. A total of 84% of the studied area, burned in a range of 4 to 22 years of fire return interval (FRI) over the 21 assessed. Only 16% of the area was affected by high to very high FRI (1 to 4 years), with an average FRI of 4.43 years. Generally, fires are more frequent and intense in September and October. These results highlight the usefulness of remote sensing in evaluating long-term spatiotemporal fire trends for effective fire management strategies and control measures in African savanna ecosystems.

Fire protection priorities in the oak forests of Iran with an emphasis on vertebrate habitat preservation

This study examines the impact of fire incidents on wildlife and habitats in the western oak forests of Iran (Zagros region). These forests are globally recognized for their exceptional biodiversity but are frequently threatened by wildfires. To achieve this, the study uses the space–time scan statistics permutation (STSSP) model to identify areas with a higher frequency of fires. The study also analyzes the effects of fires on the Zagros forests from 2000 to 2021 using remote-sensing MODIS data. Also, to understand the elements at risk of fire, burned areas were assessed based on the richness of vertebrate species, determined by the distribution of 88 vertebrate species. The results show that the annual fire rate in the Zagros forests is 76.2 (fire occurrences per year), calculated using the Poisson distribution. Findings show the highest fire rates are found in the northwest and a part of the south of the Zagros. The northwest of the Zagros also has the largest number of single fires and clusters, indicating a wide spatial distribution of fire in these regions. On the other side, it was unexpectedly found that these regions have the richest number of species and higher habitat value. The results demonstrate a significant correlation between the value of the habitat and the extent of burned areas (p < 0.05). The study also reveals that the greatest impact of fires is on small vertebrates. The overlap of frequent fire spots with the richest regions of Zagros oak forests in terms of vertebrate diversity emphasizes the need for strategic forest risk reduction planning, especially in these priority zones.

Using AutoML and generative AI to predict the type of wildfire propagation in Canadian conifer forests

Accurate prediction of wildfire behaviour is critical for safe and effective fire management and suppression. This study focused on developing and evaluating machine learning (ML) models based on a dataset collected of outdoor experimental fires in Canadian conifer forests. Binary classification models (surface fire vs. crown fire) and multi-class fire type models (surface, passive crown, active crown) were created using ensemble tree methods (Random Forest, XGBoost) and automated ML (AutoGluon, TabPFN). Generative adversarial networks (GAN) were used to generate synthetic data to overcome imbalances in the type of fire distribution. The results show automated ML methods applied to the binary problem to perform best of all tested methods, with an overall accuracy of 91%. TabPFN had the highest accuracy for the multi-class problem, with the use of GAN improving model fit. Results show overfitting issues with some of the ML models, highlighting the need of independent evaluation when ML models are developed. The TabPFN models have potential for application in supporting fire management, namely in fuel management and identifying situations with high fire spread and intensity potential that can impact firefighter safety.

Land Cover Disaggregated Fire Occurrence and Particulate Matter2.5 Relationship in the Mekong Region: A Comprehensive Study

Air pollution has become an increasing concern in the Mekong region due to seasonal vegetative burning triggered by related anthropogenic activities and climate change. While the assumption of a correlation between agriculture burning and air pollution is a common postulation, little evidence exists on the association between fire incidents and air pollution concentrations. The current study explores the relationship between satellite-derived fire occurrence, land surface characteristics, and particulate matter 2.5 (PM2.5) concentrations for the five Lower Mekong countries, namely Cambodia, Laos, Myanmar, Thailand, and Vietnam, in an effort to gain new insights into fire distributions related to air quality. Publicly available daily active fire hotspots from the VIIRS satellite instrument, annual land cover products from the MODIS satellite, and mean monthly ground-level PM2.5 estimates from the V5.GL.04 database were analyzed in two relational assessments; first, the distribution of VIIRS active fire counts and fire radiative power (FRP) temporally and spatially and secondly, the correlations between the monthly VIIRS active fire counts, cumulative monthly FRP and mean monthly PM2.5 estimates per country and land cover type. The results suggest a statistically significant positive correlation between monthly fire counts, cumulative FRP, and PM2.5 estimates for each country, which differ based on land cover. The strongest correlation between monthly fire incidences and PM2.5 estimates was found in the case of Myanmar. For all countries combined, fires detected in forests displayed the highest correlation with monthly PM2.5 estimates. This study demonstrates the use of the VIIRS active fire product and provides important insights into temporal and spatial fire distributions as baseline information for fire prevention and mitigation strategies in the Mekong region.

COMPARATIVE STUDY OF EGRESS TIME ON BRAWIJAYA STADIUM AND GOR JAYABAYA KEDIRI

Egress time in stadiums and sports buildings is one of the important things to consider in providing safety and tranquility for the audience in the building. The purpose of accessibility systems and adequate evacuation circulation planning in sports buildings is to provide evacuation routes that are easily accessible to spectators and minimize crowds and accumulation of people at the exit. This study aims to determine the most effective evacuation time at the Brawijaya Stadium and GOR Jayabaya in Kediri and the difference in the evacuation of spectators in a fire situation in open and closed buildings. This research uses simulation experimental research methods using Pathfinder and Pyrosim applications to find the most effective evacuation time in each building. The final results show that the addition of a radial gangway, the addition of exit doors, and the improvement of circulation flow effectively reduce the length of evacuation time in both buildings. At the Brawijaya Stadium, the evacuation time was 6 minutes and 59 seconds. GOR Jayabaya requires an evacuation time of 6 minutes and 56 seconds. In addition, there are differences in the distribution of smoke and fire in open and closed buildings. Keywords: Egress Time; Evacuation Time; Evacuation Circulation.

Hotspot driven air pollution during crop residue burning season in the Indo-Gangetic Plain, India

Intensive crop residue burning (CRB) in northern India triggers severe air pollution episodes over the Indo-Gangetic Plain (IGP) each year during October and November. We have quantified the contribution of hotspot districts (HSDs) and total CRB to poor air quality over the IGP. Initially, we investigated the spatiotemporal distribution of CRB fire within the domain and pinpointed five HSD in each Punjab and Haryana. Furthermore, we have simulated air quality and quantified the impact of CRB using the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem), incorporating recent anthropogenic emissions (EDGAR v5) and biomass burning emissions (FINN v2.4) inventories, along with MOZART-MOSAIC chemistry. The key finding is that HSDs contributed ∼80% and ∼50% of the total fire counts in Haryana and Punjab, respectively. The model effectively captured observed PM₂.₅ concentrations, with a normalized mean bias (NMB) below 0.2 and R-squared (R2) exceeding 0.65 at the majority of validation sites. However, some discrepancies were observed at a few sites in Delhi, Punjab, Haryana, and West Bengal. The National Capital Region experienced the highest PM₂.₅ concentrations, followed by Punjab, Haryana, Uttar Pradesh, Bihar, and West Bengal. Moreover, HSDs were responsible for about 70% of the total increase in CRB-induced PM₂.₅ in the western, central, and eastern cities, and around 50% in the northern cities. By eliminating CRB emissions across the domain, we could potentially save approximately 18,000 lives annually. Policymakers, scientists, and institutions can leverage the framework to address air pollution at national and global scales by targeting source-specific hotspots. This approach, coupled with appropriate technological and financial solutions, can contribute to achieving climate change and sustainable development goals.

Geographic Information System (GIS) Spatial Analysis to Detect the Distribution Pattern of Unused Land Fires at Ogan Ilir Regency

Land fires pose a serious threat to the environment and communities in Ogan Ilir Regency, South Sumatra. This study aims to analyze the distribution pattern of land fires using GIS spatial analysis technology. Through Sentinel-2 image classification and fire intensity analysis, it had been identified focal points of dormant land fires mainly in South Indralaya, North Indralaya, and West Pemulutan sub-districts. The results of this study provide in-depth insight into the spatial distribution of land fires and the factors that influence their occurrence. This research also produced a map of the distribution of fire hotspots in unused land areas. From the research, it can be concluded that spatial analysis can map in detail and comprehensively the burning locations on unused land. The implication of this research is the need to develop more effective mitigation strategies to address the risk of land fires in the future. Therefore, this study not only makes an important contribution to the scientific literature but also offers new directions for research and policy focused on sustainable and effective land fire risk management.

Theoretical and numerical study on ceiling temperature distribution of fire in the SRRT with curvature considering train blocking

The slopping rack railway tunnel (SRRT) with curvature is applied to pass through mountainous areas due to the terrain. And the temperature distribution under train blocking in the SRRT with curvature is significantly different when a fire occurs, posing a great threat to personnel safety. The train blocking and two curvature types of C-shaped and S-shaped are considered, and the mathematical expressions for temperature distribution with coefficients of slope and curvature are derived. The effects of slope, curvature, and train blocking on ceiling temperature are investigated using numerical simulation, and the applicability of the mathematical expressions is demonstrated through fitting. The results show that the mathematical expression for ceiling temperature distribution is a piecewise function with a stepped-down descent. The temperature attenuation is separated into three stages for C-shaped, and four stages for S-shaped. The coefficients are approximately linear with slope and curvature radius respectively. The train blocking on the ceiling maximum temperature for C-shaped is of a stronger effect than for S-shaped, and the slope on the temperature at the train tail for C-shaped is of a weaker effect than for S-shaped.

Behavior of Fire-damaged RC Beams After Strengthening with Various Techniques

High temperatures during a fire can significantly degrade the structural capacity of concrete. However, in many cases, it is possible to restore and strengthen fire-damaged concrete rather than completely rebuild damaged structures. The study considered two types of concrete (normal 25 MPa and high-strength 65 MPa) with two types of strengthening techniques: carbon-fiber-reinforced polymers (CFRP) sheets with different thicknesses of 1.5 and 2.5 mm and slurry-infiltrated fibrous concrete (SIFCON) jacketing with different fiber sizes of 20 and 30 mm. The numerical simulations and analyses were conducted to capture the complex behavior of fire-damaged concrete members (beams). A fire-damaged concrete beam subjected to an extreme or critical fire Exposure time (2 hours) was evaluated and modified using a finite element simulation approach. The simulation process included three stages: the first, subjecting the concrete beam to thermal loading; the second, reflecting the fire distribution map to another model of applying mechanical loading; and the third, involving the application of strengthening to the damaged model. The results showed that the strengthening using CFRP with a thickness of 2.5 improved the load-carrying capacity compared with SIFCON in both types of concrete. 200% improvement for the normal-strength concrete beam and a 136% improvement for the high-strength concrete beam, compared to the damaged beams. Doi: 10.28991/CEJ-2024-010-01-012 Full Text: PDF

Vegetation Fires in the Lubumbashi Charcoal Production Basin (The Democratic Republic of the Congo): Drivers, Extent and Spatiotemporal Dynamics

In the Lubumbashi charcoal production basin (LCPB) in Southeastern DR Congo, agricultural and charcoal production activities regularly give rise to fires that lead to considerable degradation of the miombo open forest. This study analyzes the drivers of the spatiotemporal distribution of active fires and burnt areas in the LCPB by processing MODIS and Landsat data. In addition, a kernel density analysis method (KDE) was used to estimate fire risk, while the effect of the road network and dwellings on vegetation fires was highlighted in areas between a 0 and 3000 m radius. The obtained results revealed that fires in the LCPB generally occur between April and November, mainly during the day, between 11 a.m. and 12 p.m. These fires are concentrated in the central and southwestern part of the LCPB, more specifically in the savannahs and near roads. From 2002 to 2022, an average of 11,237 active fires and an average of 6337 km2 of burnt areas were recorded in the LCPB. Each year, these fires peak in August, and despite their steady decline, the few fires that have affected the forests have caused more devastation (more than 2790 km2/year) than those observed in the fields and savannah. These figures highlight the imperative need to put in place fire prevention and management measures in the LCPB, with particular emphasis on awareness, monitoring, and fire-fighting measures.

Study on flame height and temperature distribution of double-deck bridge fire based on large-scale fire experiments

Vehicle fire is one of the important causes of bridge fires. This study conducted large-scale actual fire experiments by simulating heat release rates (HRR) of oil tank truck fires with 50 MW, 100 MW, and 200 MW in rectangular oil pans of varying sizes. The flame shape and spatial temperature distribution at different HRRs were studied bycontrollingvariables such as wind speed,firesource location, andlayer spacing. The results indicated that the actual HRR of the large-scale fire exceeded the anticipated value. In large-scale fire experiments, flame splitting into two main peaks was observed along the long side of the rectangular oil pan due to the coupling effect of ambient wind, long side, and sidewall effect of the diagonal web member. The average flame height was determined through image processing, and subsequently, a formula for predicting flame height during bridge fires under varying heat release rates was developed through the use of dimensionless analysis and feature length analysis. The spatial temperature distribution in the vertical direction of the axis of the center of the fire source, the temperature distribution of the diagonal web member and the bottom of the dense crossbeams, which are critical components of the bridge, were also analyzed. Furthermore, the conclusion that the flame in the lower bridge space which split into two main peaks is validated by the results. The results of this study can provide important theoretical support for investigating bridge fire resistance strategies.