Assessing the role of compound drought and heatwave events on unprecedented 2020 wildfires in the Pantanal

Abstract The year 2020 had the most catastrophic fire season over the last two decades in the Pantanal, which led to outstanding environmental impacts. Indeed, much of the Pantanal has been affected by severe dry conditions since 2019, with evidence of the 2020’s drought being the most extreme and widespread ever recorded in the last 70 years. Although it is unquestionable that this mega-drought contributed significantly to the increase of fire risk, so far, the 2020’s fire season has been analyzed at the univariate level of a single climate event, not considering the co-occurrence of extreme and persistent temperatures with soil dryness conditions. Here, we show that similarly to other areas of the globe, the influence of land-atmosphere feedbacks contributed decisively to the simultaneous occurrence of dry and hot spells (HPs), exacerbating fire risk. The ideal synoptic conditions for strong atmospheric heating and large evaporation rates were present, in particular during the HPs, when the maximum temperature was, on average, 6 ºC above the normal. The short span of the period during those compound drought-heatwave (CDHW) events accounted for 55% of the burned area of 2020. The vulnerability in the northern forested areas was higher than in the other areas, revealing a synergistic effect between fuel availability and weather-hydrological conditions. Accordingly, where fuel is not a limiting factor, fire activity tends to be more modelled by CDHW events. Our work advances beyond an isolated event-level basis towards a compound and cascading natural hazards approach, simultaneously estimating the contribution of drought and heatwaves to fuelling extreme fire outbreaks in the Pantanal such as those in 2020. Thus, these findings are relevant within a broader context, as the driving mechanisms apply across other ecosystems, implying higher flammability conditions and further efforts for monitoring and predicting such extreme events.

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Integrating past variability in climate-driven Mediterranean fire hazard assessments for 2020-2100

10.21203/rs.3.rs-164555/v1 ◽

2021 ◽

Author(s):

Marion Lestienne ◽

Boris Vannière ◽

Thomas Curt ◽

Isabelle Jouffroy-Bapicot ◽

Christelle Hély

Keyword(s):

Fire Hazard ◽

Fire Risk ◽

Future Climate ◽

Effect Of Temperature ◽

Fire Season ◽

Burned Area ◽

Prevention Policy ◽

Rcp Scenarios ◽

Precipitation Decrease ◽

The Future

Abstract In the Mediterranean basin, Corsica (French island) harbours among the best-preserved Mediterranean forest ecosystems and its high biodiversity could be threatened by the climate and disturbance-regime changes due to the global warming. This study aims i) to estimate the future climate-related fire hazard in Corsica for the current century (2020–2100) based on two RCP scenarios (RCP4.5 and RCP8.5), and ii) to compare the predicted trends with the entire Holocene period for which fire hazard has previously been assessed. An ensemble of future climate simulations from two IPCC RCP scenarios has been used to compute the Monthly Drought Code (MDC) and the Fire Season Length (FSL) and to assess the level of fire hazard assessment. Here, we show that the MDC and the FSL would both strongly increase over the next decades due to the combined effect of temperature increase and precipitation decrease in the Corsica region. Moreover, the maximum Holocene FLS (7000 to 9000 years ago), will be reached (and even exceeded depending upon the scenario) after 2040. For the first time in the Holocene, we may be confronted to an increase in the number of fire-prone months driven by climate combined with many human-caused ignitions. This combination should increase the burned area from 15–140%. For the next 30 years, the game seems to be already played as both RCP scenarios resulted in similar increase in fire hazard intensity and duration. It is thus mandatory to reconsider fire-management and fire-prevention policy to mitigate the future fire risk, and its catastrophic consequences for ecosystems, population, and economy.

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Climate drivers of the 2017 devastating fires in Portugal

Scientific Reports ◽

10.1038/s41598-019-50281-2 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 22

Author(s):

Marco Turco ◽

Sonia Jerez ◽

Sofia Augusto ◽

Patricia Tarín-Carrasco ◽

Nuno Ratola ◽

...

Keyword(s):

High Temperature ◽

Climatic Factors ◽

Standardized Precipitation Index ◽

Fire Risk ◽

Fire Season ◽

Burned Area ◽

Moisture Index ◽

Temperature Conditions ◽

The Standardized Precipitation Index ◽

Extreme Fire

Abstract A record 500,000 hectares burned in Portugal during the extreme wildfire season of 2017, with more than 120 human lives lost. Here we analyse the climatic factors responsible for the burned area (BA) from June to October series in Portugal for the period 1980–2017. Superposed onto a substantially stationary trend on BA data, strong oscillations on shorter time scales were detected. Here we show that they are significantly affected by the compound effect of summer (June-July-August) drought and high temperature conditions during the fire season. Drought conditions were calculated using the Standardized Precipitation Evapotranspiration Index (SPEI), the Standardized Precipitation Index (SPI) and the Standardized Soil Moisture Index (SSI). Then the extent to which the burned area has diverged from climate-expected trends was assessed. Our results indicate that in the absence of other drivers, climate change would have led to higher BA values. In addition, the 2017 extreme fire season is well captured with the model forced with climate drivers only, suggesting that the extreme fire season of 2017 could be a prelude to future conditions and likewise events. Indeed, the expected further increase of drought and high temperature conditions in forthcoming decades, point at a potential increase of fire risk in this region. The climate-fire model developed in this study could be useful to develop more skilled seasonal predictions capable of anticipating potentially hazardous conditions.

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Understanding the Impact of Different Landscape-Level Fuel Management Strategies on Wildfire Hazard in Central Portugal

Forests ◽

10.3390/f12050522 ◽

2021 ◽

Vol 12 (5) ◽

pp. 522

Author(s):

Akli Benali ◽

Ana C. L. Sá ◽

João Pinho ◽

Paulo M. Fernandes ◽

José M. C. Pereira

Keyword(s):

Management Strategies ◽

Treatment Strategies ◽

Fire Season ◽

Burned Area ◽

Treatment Area ◽

Fuel Treatment ◽

The North ◽

Wildfire Hazard ◽

Central Portugal ◽

The Impact

The extreme 2017 fire season in Portugal led to widespread recognition of the need for a paradigm shift in forest and wildfire management. We focused our study on Alvares, a parish in central Portugal located in a fire-prone area, which had 60% of its area burned in 2017. We evaluated how different fuel treatment strategies may reduce wildfire hazard in Alvares through (i) a fuel break network with different extents corresponding to different levels of priority and (ii) random fuel treatments resulting from a potential increase in stand-level management intensity. To assess this, we developed a stochastic wildfire simulation system (FUNC-SIM) that integrates uncertainties in fuel distribution over the landscape. If the landscape remains unchanged, Alvares will have large burn probabilities in the north, northeast and center-east areas of the parish that are very often associated with high fireline intensities. The different fuel treatment scenarios decreased burned area between 12.1–31.2%, resulting from 1–4.6% increases in the annual treatment area and reduced the likelihood of wildfires larger than 5000 ha by 10–40%. On average, simulated burned area decreased 0.22% per each ha treated, and cost-effectiveness decreased with increasing area treated. Overall, both fuel treatment strategies effectively reduced wildfire hazard and should be part of a larger, holistic and integrated plan to reduce the vulnerability of the Alvares parish to wildfires.

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Demographic Effects of Severe Fire in Montane Shrubland on Tasmania’s Central Plateau

Fire ◽

10.3390/fire4030032 ◽

2021 ◽

Vol 4 (3) ◽

pp. 32

Author(s):

Judy A. Foulkes ◽

Lynda D. Prior ◽

Steven W. J. Leonard ◽

David M. J. S. Bowman

Keyword(s):

Woody Species ◽

Fire Frequency ◽

Fire Season ◽

Burned Area ◽

Large Area ◽

Seedling Regeneration ◽

Central Plateau ◽

Conservation Area ◽

Severe Fire ◽

Representative Area

Australian montane sclerophyll shrubland vegetation is widely considered to be resilient to infrequent severe fire, but this may not be the case in Tasmania. Here, we report on the vegetative and seedling regeneration response of a Tasmanian non-coniferous woody montane shrubland following a severe fire, which burned much of the Great Pine Tier in the Central Plateau Conservation Area during the 2018–2019 fire season when a historically anomalously large area was burned in central Tasmania. Our field survey of a representative area burned by severe crown fire revealed that more than 99% of the shrubland plants were top-killed, with only 5% of the burnt plants resprouting one year following the fire. Such a low resprouting rate means the resilience of the shrubland depends on seedling regeneration from aerial and soil seedbanks or colonization from plants outside the burned area. Woody species’ seedling densities were variable but generally low (25 m−2). The low number of resprouters, and reliance on seedlings for recovery, suggest the shrubland may not be as resilient to fire as mainland Australian montane shrubland, particularly given a warming climate and likely increase in fire frequency.

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Using the Landsat Burned Area Products to Derive Fire History Relevant for Fire Management and Conservation in the State of Florida, Southeastern USA

Fire ◽

10.3390/fire4020026 ◽

2021 ◽

Vol 4 (2) ◽

pp. 26

Author(s):

Casey Teske ◽

Melanie K. Vanderhoof ◽

Todd J. Hawbaker ◽

Joe Noble ◽

John Kevin Hiers

Keyword(s):

Prescribed Fire ◽

Spatial Data ◽

Fire History ◽

Fire Management ◽

Fire Behavior ◽

Fire Risk ◽

Behavior Modeling ◽

Burned Area ◽

Burned Areas ◽

Burn Probability

Development of comprehensive spatially explicit fire occurrence data remains one of the most critical needs for fire managers globally, and especially for conservation across the southeastern United States. Not only are many endangered species and ecosystems in that region reliant on frequent fire, but fire risk analysis, prescribed fire planning, and fire behavior modeling are sensitive to fire history due to the long growing season and high vegetation productivity. Spatial data that map burned areas over time provide critical information for evaluating management successes. However, existing fire data have undocumented shortcomings that limit their use when detailing the effectiveness of fire management at state and regional scales. Here, we assessed information in existing fire datasets for Florida and the Landsat Burned Area products based on input from the fire management community. We considered the potential of different datasets to track the spatial extents of fires and derive fire history metrics (e.g., time since last burn, fire frequency, and seasonality). We found that burned areas generated by applying a 90% threshold to the Landsat burn probability product matched patterns recorded and observed by fire managers at three pilot areas. We then created fire history metrics for the entire state from the modified Landsat Burned Area product. Finally, to show their potential application for conservation management, we compared fire history metrics across ownerships for natural pinelands, where prescribed fire is frequently applied. Implications of this effort include increased awareness around conservation and fire management planning efforts and an extension of derivative products regionally or globally.

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Quantitative Analysis of Forest Fires in Southeastern Australia Using SAR Data

Remote Sensing ◽

10.3390/rs13122386 ◽

2021 ◽

Vol 13 (12) ◽

pp. 2386

Author(s):

Aqil Tariq ◽

Hong Shu ◽

Qingting Li ◽

Orhan Altan ◽

Mobushir Riaz Khan ◽

...

Keyword(s):

Forest Fires ◽

Prescribed Burning ◽

Fire Risk ◽

Fire Season ◽

Prescribed Burn ◽

Backscatter Coefficient ◽

Prescribed Burns ◽

Southeastern Australia ◽

Sar Data ◽

Sar Imagery

Prescribed burning is a common strategy for minimizing forest fire risk. Fire is introduced under specific environmental conditions, with explicit duration, intensity, and rate of spread. Such conditions deviate from those encountered during the fire season. Prescribed burns mostly affect surface fuels and understory vegetation, an outcome markedly different when compared to wildfires. Data on prescribed burning are crucial for evaluating whether land management targets have been reached. This research developed a methodology to quantify the effects of prescribed burns using multi-temporal Sentinel-1 Synthetic Aperture Radar (SAR) imagery in the forests of southeastern Australia. C-band SAR datasets were specifically used to statistically explore changes in radar backscatter coefficients with the intensity of prescribed burns. Two modeling approaches based on pre- and post-fire ratios were applied for evaluating prescribed burn impacts. The effects of prescribed burns were documented with an overall accuracy of 82.3% using cross-polarized backscatter (VH) SAR data under dry conditions. The VV polarization indicated some potential to detect burned areas under wet conditions. The findings in this study indicate that the C-band SAR backscatter coefficient has the potential to evaluate the effectiveness of prescribed burns due to its sensitivity to changes in vegetation structure.

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Emerging Anthropogenic Influences on the Southcentral Alaska Temperature and Precipitation Extremes and Related Fires in 2019

Land ◽

10.3390/land10010082 ◽

2021 ◽

Vol 10 (1) ◽

pp. 82

Author(s):

Uma S. Bhatt ◽

Rick T. Lader ◽

John E. Walsh ◽

Peter A. Bieniek ◽

Richard Thoman ◽

...

Keyword(s):

Climate Model ◽

Simulation Analysis ◽

Historical Context ◽

Fire Risk ◽

Internal Variability ◽

Fire Season ◽

Temperature And Precipitation ◽

Southcentral Alaska ◽

Meteorological Observations ◽

Climate Model Simulations

The late-season extreme fire activity in Southcentral Alaska during 2019 was highly unusual and consequential. Firefighting operations had to be extended by a month in 2019 due to the extreme conditions of hot summer temperature and prolonged drought. The ongoing fires created poor air quality in the region containing most of Alaska’s population, leading to substantial impacts to public health. Suppression costs totaled over $70 million for Southcentral Alaska. This study’s main goals are to place the 2019 season into historical context, provide an attribution analysis, and assess future changes in wildfire risk in the region. The primary tools are meteorological observations and climate model simulations from the NCAR CESM Large Ensemble (LENS). The 2019 fire season in Southcentral Alaska included the hottest and driest June–August season over the 1979–2019 period. The LENS simulation analysis suggests that the anthropogenic signal of increased fire risk had not yet emerged in 2019 because of the CESM’s internal variability, but that the anthropogenic signal will emerge by the 2040–2080 period. The effect of warming temperatures dominates the effect of enhanced precipitation in the trend towards increased fire risk.

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PERFIL DOS INCÊNDIOS FLORESTAIS NO BRASIL DE 1994 A 1997

FLORESTA ◽

10.5380/rf.v32i2.2287 ◽

2002 ◽

Vol 32 (2) ◽

Cited By ~ 2

Author(s):

Ronaldo Viana Soares ◽

Juliana Ferreira Santos

Keyword(s):

Forest Fire ◽

Vegetation Type ◽

Secondary Growth ◽

Minas Gerais ◽

Size Class ◽

Fire Season ◽

Burned Area ◽

Native Forest ◽

Fire Statistics ◽

Fire Control

O conhecimento do perfil dos incêndios florestais é muito importante para o planejamento do controle dos mesmos. O objetivo deste trabalho foi estabelecer o perfil dos incêndios florestais no país através de dados coletados, em áreas protegidas, no período de 1994 a 1997, através de formulários preenchidos por empresas e instituições florestais. Foram registrados e informados 1.957 incêndios e apesar deste número não representar a totalidade dos incêndios ocorridos no período estudado, constituiu-se numa base confiável para se conhecer as principais características dos incêndios. Os resultados mostraram que a área média atingida por incêndio no período analisado foi de aproximadamente 135 ha, sendo Minas Gerais o estado líder, tanto em número de incêndios informados (62,7% do total) como em área queimada (25,2%). O grupo Incendiários foi a principal causa dos incêndios, com 56,6% das ocorrências, vindo a seguir as Queimas para limpeza com 22,1%. Com relação à área queimada o grupo Queimas para limpeza , com 74,1% da superfície atingida, foi a principal causa, ficando o grupo Incendiários em segundo lugar com 19,8%. A principal estação de incêndios no país se estende de julho a novembro, quando ocorreram 79,2% dos incêndios, correspondendo a 98,6% da área atingida. O maior número de incêndios (39,7% das ocorrências) foi registrado em Outro tipo de vegetação, que inclui cerrado, capoeira e campo. Com relação à área atingida, entretanto, 92,5% foi registrada em Florestas Nativas. Quanto à distribuição dos incêndios através das classes de tamanho, 23,9% foi enquadrado na classe I ( 0,1 ha). É importante ressaltar que quanto maior a eficiência no combate aos incêndios, maior é a concentração dos mesmos na classe I. Apesar de corresponder a apenas 2,4% das ocorrências, os incêndios da classe V ( 200,0 ha) foram responsáveis por 94,5% da área queimada. FOREST FIRE STATISTICS IN BRAZIL FROM 1994 TO 1997 Abstract Forest fire statistics knowledge is an important tool for fire control planning. The objective of this research was to collect information on forest fire occurrence in Brazilian protected areas in the period of 1994 to 1997. The analyzed variables were the number of fires and burned areas per state of the federation, monthly distribution, probable causes, affected vegetation, size class distribution, and average burned area per fire. Results showed that the average burned area per fire was approximately 135 ha and Minas Gerais ranked first, both in number of registered fires (62.7%) and burned surface (25.2%). Incendiary, with 56.6% of the occurrences was the leading cause, followed by debris burning with 22.1%. However, as for the affected area, Debris burning was the leading cause (74.1%), followed by Incendiary (19.8%). The fire season extends from July to November, when 79.2% of the fires occurred, corresponding to 98.6% of the burned surface. Miscellaneous, that includes savanna, secondary growth forest, and grassland were the most affected vegetation type (39.7% of the occurrences). In relation to the burned surface, Native Forest (92.5%) ranked first. The distribution of the registered fires through the size classes presented 23.9% of the occurrences in Class I ( 0.1 ha), whereas 94.5% of the burned area were result of Class V ( 200 ha) fires. Size Class II (0.1 to 4.0 ha), with 49.1% of the occurrences, ranked first in number of registered fires during the analyzed period.

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Estimates of biomass burning emissions in tropical Asia based on satellite-derived data

Atmospheric Chemistry and Physics ◽

10.5194/acp-10-2335-2010 ◽

2010 ◽

Vol 10 (5) ◽

pp. 2335-2351 ◽

Cited By ~ 78

Author(s):

D. Chang ◽

Y. Song

Keyword(s):

Biomass Burning ◽

Atmospheric Chemistry ◽

Crop Residue ◽

Fire Season ◽

Burned Area ◽

Published Data ◽

Tropical Asia ◽

Fire Emissions ◽

Burned Areas ◽

In Fire

Abstract. Biomass burning in tropical Asia emits large amounts of trace gases and particulate matter into the atmosphere, which has significant implications for atmospheric chemistry and climatic change. In this study, emissions from open biomass burning over tropical Asia were evaluated during seven fire years from 2000 to 2006 (1 March 2000–31 February 2007). The size of the burned areas was estimated from newly published 1-km L3JRC and 500-m MODIS burned area products (MCD45A1). Available fuel loads and emission factors were assigned to each vegetation type in a GlobCover characterisation map, and fuel moisture content was taken into account when calculating combustion factors. Over the whole period, both burned areas and fire emissions showed clear spatial and seasonal variations. The size of the L3JRC burned areas ranged from 36 031 km2 in fire year 2005 to 52 303 km2 in 2001, and the MCD45A1 burned areas ranged from 54 790 km2 in fire year 2001 to 148 967 km2 in 2004. Comparisons of L3JRC and MCD45A1 burned areas using ground-based measurements and other satellite data were made in several major burning regions, and the results suggest that MCD45A1 generally performed better than L3JRC, although with a certain degree of underestimation in forest areas. The average annual L3JRC-based emissions were 123 (102–152), 12 (9–15), 1.0 (0.7–1.3), 1.9 (1.4–2.6), 0.11 (0.09–0.12), 0.89 (0.63–1.21), 0.043 (0.036–0.053), 0.021 (0.021–0.023), 0.41 (0.34–0.52), 3.4 (2.6–4.3), and 3.6 (2.8–4.7) Tg yr−1 for CO2, CO, CH4, NMHCs, NOx, NH3, SO2, BC, OC, PM2.5, and PM10, respectively, whereas MCD45A1-based emissions were 122 (108–144), 9.3 (7.7–11.7), 0.63 (0.46–0.86), 1.1 (0.8–1.6), 0.11 (0.10–0.13), 0.54 (0.38–0.76), 0.043 (0.038–0.051), 0.033 (0.032–0.037), 0.39 (0.34–0.47), 3.0 (2.6–3.7), and 3.3 (2.8–4.0) Tg yr−1. Forest burning was identified as the major source of the fire emissions due to its high carbon density. Although agricultural burning was the second highest contributor, it is possible that some crop residue combustion was missed by satellite observations. This possibility is supported by comparisons with previously published data, and this result may be due to the small size of the field crop residue burning. Fire emissions were mainly concentrated in Indonesia, India, Myanmar, and Cambodia. Furthermore, the peak in the size of the burned area was generally found in the early fire season, whereas the maximum fire emissions often occurred in the late fire season.

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Needle Senescence Affects Fire Behavior in Aleppo Pine (Pinus halepensis Mill.) Stands: A Simulation Study

Forests ◽

10.3390/f11101054 ◽

2020 ◽

Vol 11 (10) ◽

pp. 1054 ◽

Cited By ~ 1

Author(s):

Rodrigo Balaguer-Romano ◽

Rubén Díaz-Sierra ◽

Javier Madrigal ◽

Jordi Voltas ◽

Víctor Resco de Dios

Keyword(s):

Mediterranean Basin ◽

Fire Behavior ◽

Western Mediterranean ◽

Aleppo Pine ◽

Fire Season ◽

Burned Area ◽

Crown Fire ◽

Wind Speeds ◽

Western Mediterranean Basin ◽

Needle Senescence

Research Highlights: Pre-programmed cell death in old Aleppo pine needles leads to low moisture contents in the forest canopy in July, the time when fire activity nears its peak in the Western Mediterranean Basin. Here, we show, for the first time, that such needle senescence may increase fire behavior and thus is a potential mechanism explaining why the bulk of the annual burned area in the region occurs in early summer. Background and Objectives: The brunt of the fire season in the Western Mediterranean Basin occurs at the beginning of July, when live fuel moisture content is near its maximum. Here, we test whether a potential explanation to this conundrum lies in Aleppo pine needle senescence, a result of pre-programmed cell death in 3-years-old needles, which typically occurs in the weeks preceding the peak in the burned area. Our objective was to simulate the effects of needle senescence on fire behavior. Materials and Methods: We simulated the effects of needle senescence on canopy moisture and structure. Fire behavior was simulated across different phenological scenarios and for two highly contrasting Aleppo pine stand structures, a forest, and a shrubland. Wildfire behavior simulations were done with BehavePlus6 across a wide range of wind speeds and of dead fine surface fuel moistures. Results: The transition from surface to passive crown fire occurred at lower wind speeds under simulated needle senescence in the forest and in the shrubland. Transitions to active crown fire only occurred in the shrubland under needle senescence. Maximum fire intensity and severity were always recorded in the needle senescence scenario. Conclusions: Aleppo pine needle senescence may enhance the probability of crown fire development at the onset of the fire season, and it could partly explain the concentration of fire activity in early July in the Western Mediterranean Basin.

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