scholarly journals Estimating carbon emissions from African wildfires

2009 ◽  
Vol 6 (3) ◽  
pp. 349-360 ◽  
Author(s):  
V. Lehsten ◽  
K. Tansey ◽  
H. Balzter ◽  
K. Thonicke ◽  
A. Spessa ◽  
...  
Keyword(s):  
Carbon Emissions ◽  
Net Primary Productivity ◽  
Fire Regime ◽  
Climatic Conditions ◽  
Burned Area ◽  
Similar Response ◽  
Response Patterns ◽  
Model Framework ◽  
Burnt Area ◽  
In Fire

Abstract. We developed a technique for studying seasonal and interannual variation in pyrogenic carbon emissions from Africa using a modelling approach that scales burned area estimates from L3JRC, a map recently generated from remote sensing of burn scars instead of active fires. Carbon fluxes were calculated by the novel fire model SPITFIRE embedded within the dynamic vegetation model framework LPJ-GUESS, using daily climate input. For the time period from 2001 to 2005 an average area of 195.5±24×104 km2 was burned annually, releasing an average of 723±70 Tg C to the atmosphere; these estimates for the biomass burned are within the range of previously published estimates. Despite the fact that the majority of wildfires are ignited by humans, strong relationships between climatic conditions (particularly precipitation), net primary productivity and overall biomass burnt emerged. Our investigation of the relationships between burnt area and carbon emissions and their potential drivers available litter and precipitation revealed uni-modal responses to annual precipitation, with a maximum around 1000 mm for burned area and emissions, or 1200 mm for litter availability. Similar response patterns identified in savannahs worldwide point to precipitation as a chief determinant for short-term variation in fire regime. A considerable variability that cannot be explained by fire-precipitation relationships alone indicates the existence of additional factors that must be taken into account.

scholarly journals Estimating carbon emissions from African wildfires

2008 ◽  
Vol 5 (4) ◽  
pp. 3091-3122 ◽  
Author(s):  
V. Lehsten ◽  
K. J. Tansey ◽  
H. Balzter ◽  
K. Thonicke ◽  
A. Spessa ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Carbon Emissions ◽  
Management Practice ◽  
Climatic Conditions ◽  
Total Carbon ◽  
Annual Precipitation ◽  
Burned Area ◽  
Biogeochemical Model ◽  
Model Framework ◽  
Land Management Practice

Abstract. Africa is a continent dominated by fire. Vegetation fires, occurring naturally or human-ignited as a land management practice, have a long history in the continent's savannah ecosystems. These fires contribute substantially to the total carbon emissions (e.g. as CO2, CO, CH4, Volatile Organic Compounds, Black Carbon) over large parts of the continent. Many recent attempts to assess the total area burnt and the amount of carbon emitted have been based on satellite remote sensing of active fires. To calculate emissions, the burned area estimates are typically multiplied with emission factors that are specific for each compound and land cover type, or used to distribute output from a biogeochemical model spatially. We developed a technique for estimating carbon emissions using a modelling approach to scale burned area estimates from L3JRC, a map recently generated from remote sensing of burn scars instead of active fires. Carbon fluxes were calculated by the novel fire model SPITFIRE embedded within the dynamic vegetation model framework LPJ-GUESS, using daily climate input. For the time period from 2001 to 2005 an average area of 195.5±24×104 km2 was burned annually, releasing an average of 723±70 Tg C to the atmosphere; these estimates for the biomass burned are within the range of previously published estimates. Despite the fact that the majority of wildfires are ignited by humans, strong relationships with climatic conditions have been identified in savannas worldwide, driving inter-annual variability. Our investigation of the relationships amongst carbon emissions and its potential drivers, available litter and precipitation showed that burned area as well as carbon emissions show a uni-modal response to precipitation with a maximum at ca. 1000 mm annual precipitation for burned area and emissions and a maximum of ca. 1200 mm annual precipitation for litter availability.

Fire regime shift linked to increased forest density in a piñon–juniper savanna landscape

2014 ◽  
Vol 23 (2) ◽  
pp. 234 ◽  
Author(s):  
Ellis Q. Margolis
Keyword(s):  
Regime Shift ◽  
Fire History ◽  
Fire Regime ◽  
Fire Regimes ◽  
Fire Frequency ◽  
Climatic Conditions ◽  
Tree Density ◽  
High Severity ◽  
Wide Range ◽  
In Fire

Piñon–juniper (PJ) fire regimes are generally characterised as infrequent high-severity. However, PJ ecosystems vary across a large geographic and bio-climatic range and little is known about one of the principal PJ functional types, PJ savannas. It is logical that (1) grass in PJ savannas could support frequent, low-severity fire and (2) exclusion of frequent fire could explain increased tree density in PJ savannas. To assess these hypotheses I used dendroecological methods to reconstruct fire history and forest structure in a PJ-dominated savanna. Evidence of high-severity fire was not observed. From 112 fire-scarred trees I reconstructed 87 fire years (1547–1899). Mean fire interval was 7.8 years for fires recorded at ≥2 sites. Tree establishment was negatively correlated with fire frequency (r=–0.74) and peak PJ establishment was synchronous with dry (unfavourable) conditions and a regime shift (decline) in fire frequency in the late 1800s. The collapse of the grass-fuelled, frequent, surface fire regime in this PJ savanna was likely the primary driver of current high tree density (mean=881treesha–1) that is >600% of the historical estimate. Variability in bio-climatic conditions likely drive variability in fire regimes across the wide range of PJ ecosystems.

Inter- and intra-annual profiles of fire regimes in the managed forests of Canada and implications for resource sharing

2012 ◽  
Vol 21 (4) ◽  
pp. 328 ◽  
Author(s):  
Steen Magnussen ◽  
Stephen W. Taylor
Keyword(s):  
Resource Sharing ◽  
Joint Distribution ◽  
Fire Management ◽  
Fire Regime ◽  
Fire Regimes ◽  
Fire Season ◽  
Burned Area ◽  
Fire Activity ◽  
In Fire ◽  
Regional Synchrony

Year-to-year variation in fire activity in Canada constitutes a key challenge for fire management agencies. Interagency sharing of fire management resources has been ongoing on regional, national and international scales in Canada for several decades to better cope with peaks in resource demand. Inherent stressors on these schemes determined by the fire regimes in constituent jurisdictions are not well known, nor described by averages. We developed a statistical framework to examine the likelihood of regional synchrony of peaks in fire activity at a timescale of 1 week. Year-to-year variations in important fire regime variables and 48 regions in Canada are quantified by a joint distribution and profiled at the Provincial or Territorial level. The fire regime variables capture the timing of the fire season, the average number of fires, area burned, and the timing and extent of annual maxima. The onset of the fire season was strongly correlated with latitude and longitude. Regional synchrony in the timing of the maximum burned area within fire seasons delineates opportunities for and limitations to sharing of fire suppression resources during periods of stress that were quantified in Monte Carlo simulations from the joint distribution.

scholarly journals Exploring spatial-temporal dynamics of fire regime features at mainland Spain

2017 ◽  
Author(s):  
Adrián Jiménez-Ruano ◽  
Marcos Rodrigues Mimbrero ◽  
Juan de la Riva Fernández
Keyword(s):  
Temporal Dynamics ◽  
Fire Regime ◽  
Fire Frequency ◽  
Change Point Detection ◽  
Burnt Area ◽  
Temporal Behaviour ◽  
Sen’S Slope ◽  
Large Fires ◽  
The Mediterranean ◽  
In Fire

Abstract. This paper explores spatial-temporal dynamics in fire regime features, such as fire frequency, burnt area, large fires, and natural- and human-caused fires, as an essential part of fire regime characterisation. Changes in fire features are analysed at different spatial–regional and provincial/NUTS3 levels, together with summer and winter temporal scales, using historical fire data from Spain for the period 1974–2013. Temporal shifts in fire features are investigated by means of change point detection procedures – Pettitt test, AMOC (At Most One Change), PELT (Pruned Exact Linear Time) and BinSeg (Binary Segmentation) – at regional level to identify changes in the time series of the features. A trend analysis was conducted using the Mann–Kendall and Sen's slope tests at both regional and NUTS3 level. Finally, we applied a Principal Component Analysis (PCA) and Varimax Rotation to trend outputs – mainly Sen's slope values – to summarize overall temporal behaviour, also to explore potential links in the evolution of fire features. Our results suggest that most fire features show remarkable shifts between the late 1980s and the first half of the 1990s. Mann–Kendall outputs revealed negative trends in the Mediterranean region. Results from Sen's slope suggest high spatial and intra-annual variability across the study area. Fire activity related to human sources seems to be experiencing an overall decrease in the north-west provinces, particularly pronounced during summer. Conversely, the hinterlands and the Mediterranean coast are gradually becoming less fire-affected. Finally, PCA enabled trends to be synthesized into four main components: winter fire frequency (PC1), summer burnt area (PC2), large fires (PC3) and natural fires (PC4).

scholarly journals Sensitivity of simulated historical burned area to environmental andanthropogenic controls: A comparison of seven fire models

2019 ◽  
Author(s):  
Lina Teckentrup ◽  
Sandy P. Harrison ◽  
Stijn Hantson ◽  
Angelika Heil ◽  
Joe R. Melton ◽  
...  
Keyword(s):  
Land Use ◽  
Global Change ◽  
Fire Regime ◽  
Fire Behavior ◽  
Fire Regimes ◽  
Burned Area ◽  
Strong Response ◽  
Fire Models ◽  
In Fire ◽  
The Impact

Abstract. Understanding how fire regimes change over time is of major importance for understanding their future impact on the Earth system, including society. Large differences in simulated burned area between fire models show that there is substantial uncertainty associated with modelling global change impacts on fire regimes. We draw here on sensitivity simulations made by seven global dynamic vegetation models participating in the Fire Model Intercomparison Project (FireMIP) to understand how differences in models translate into differences in fire regime projections. The sensitivity experiments isolate the impact of the individual drivers of fire, which are prescribed in the simulations. Specifically these drivers are atmospheric CO2, population density, land-use change, lightning and climate. The seven models capture spatial patterns in burned area. However, they show considerable differences in the burned area trends since 1900. We analyse the trajectories of differences between the sensitivity and reference simulation to improve our understanding of what drives the global trend in burned area. Where it is possible, we link the inter-model differences to model assumptions. Overall, these analyses reveal that the strongest differences leading to diverging trajectories are related to the way anthropogenic ignitions and suppression, as well as the effects of land-use on vegetation and fire, are incorporated in individual models. This points to a need to improve our understanding and model representation of the relationship between human activities and fire to improve our abilities to model fire for global change applications. Only two models show a strong response to CO2 and the response to lightning on global scale is low for all models. The sensitivity to climate shows a spatially heterogeneous response and globally only two models show a significant trend. It was not possible to attribute the climate-induced changes in burned area to model assumptions or specific climatic parameters. However, the strong influence of climate on the inter-annual variability in burned area, shown by all the models, shows that we need to pay attention to the simulation of fire weather but also meteorological influences on biomass accumulation and fuel properties in order to better capture extremes in fire behavior.

scholarly journals Exploring spatial–temporal dynamics of fire regime features in mainland Spain

2017 ◽  
Vol 17 (10) ◽  
pp. 1697-1711 ◽  
Author(s):  
Adrián Jiménez-Ruano ◽  
Marcos Rodrigues Mimbrero ◽  
Juan de la Riva Fernández
Keyword(s):  
Temporal Dynamics ◽  
Fire Regime ◽  
Fire Frequency ◽  
Change Point Detection ◽  
Burnt Area ◽  
Temporal Behaviour ◽  
Sen’S Slope ◽  
Large Fires ◽  
The Mediterranean ◽  
In Fire

Abstract. This paper explores spatial–temporal dynamics in fire regime features, such as fire frequency, burnt area, large fires and natural- and human-caused fires, as an essential part of fire regime characterization. Changes in fire features are analysed at different spatial – regional and provincial/NUTS3 – levels, together with summer and winter temporal scales, using historical fire data from Spain for the period 1974–2013. Temporal shifts in fire features are investigated by means of change point detection procedures – Pettitt test, AMOC (at most one change), PELT (pruned exact linear time) and BinSeg (binary segmentation) – at a regional level to identify changes in the time series of the features. A trend analysis was conducted using the Mann–Kendall and Sen's slope tests at both the regional and NUTS3 level. Finally, we applied a principal component analysis (PCA) and varimax rotation to trend outputs – mainly Sen's slope values – to summarize overall temporal behaviour and to explore potential links in the evolution of fire features. Our results suggest that most fire features show remarkable shifts between the late 1980s and the first half of the 1990s. Mann–Kendall outputs revealed negative trends in the Mediterranean region. Results from Sen's slope suggest high spatial and intra-annual variability across the study area. Fire activity related to human sources seems to be experiencing an overall decrease in the northwestern provinces, particularly pronounced during summer. Similarly, the Hinterland and the Mediterranean coast are gradually becoming less fire affected. Finally, PCA enabled trends to be synthesized into four main components: winter fire frequency (PC1), summer burnt area (PC2), large fires (PC3) and natural fires (PC4).

scholarly journals Burned area trends in the Brazilian Cerrado: the roles of climate and anthropogenic drivers

2020 ◽  
Author(s):  
Patrícia S. Silva ◽  
Julia A. Rodrigues ◽  
Filippe L. M. Santos ◽  
Joana Nogueira ◽  
Allan A. Pereira ◽  
...  
Keyword(s):  
Land Use ◽  
Fire Management ◽  
Fire Regime ◽  
Fire Season ◽  
Burned Area ◽  
Eastern Region ◽  
Fire Weather Index ◽  
North Eastern ◽  
In Fire ◽  
Anthropogenic Drivers

<p>Fire is a natural disturbance in the Brazilian savannas, Cerrado, with substantial ecological and economic impacts. Most studies have characterized the fire regime in this biome using climate drivers but neglected the geographical variation of anthropogenic activities. These factors can trigger inappropriate fire-fighting decisions and biodiversity conservation policies. This takes special relevance in fire-prone biomes with recent fire management policies as Cerrado, which have been highly modified over the last decades due to changes in land use and climate. </p><p>Here, we aim to identify how variations in climate and anthropogenic drivers influence burned area (BA) trends at the regional level (microregions) in Cerrado. We evaluated satellite-derived BA (MCD64, collection 6) for 172 microregions from 2001 to 2018 across the entire biome. The Canadian Forest Fire Weather Index (FWI) was used as a proxy of climate using meteorological variables from ECMWF’s ERA5 reanalysis product. The human leverage, considered here as population density (PD) and land use (LU), were derived, respectively, from the annual census of the Brazillian Institute of Geography and Statistics (IBGE) and from a Brazilian platform of annual land use/cover mapping (MapBiomas). Recent BA trends considering the drivers FWI, LU and PD, were estimated using the non-parametric Theil-Sen regression and the modified Mann-Kendall test. </p><p>Results showed BA trends over the last 18 years were significant and spatially contrasted along Cerrado: positive trends were found in the north-eastern region (in particular, the most recent agricultural frontier in Brazil: MATOPIBA) whereas the south-western region showed negative trends. PD showed positive trends in all microregions and, similarly, LU obtained positive trends over most of Cerrado. Positive FWI trends were also found over the central and north-eastern regions and FWI was the driver that explained most of BA variance in Cerrado. LU and PD were found to have much more complex relations with BA. Moreover, regarding the seasonal variability of microregions with positive and negative trends, the former were found to begin earlier in June and last longer, indicating that the overall fire season in Cerrado may be extending. </p><p>The approach presented here allows the exploration of recent trends affecting fires, crucial to inform and support better allocation of resources in fire management under current and future conditions.</p><p>The study was funded by Conselho Nacional de Desenvolvimento Científico e Tecnológico, Brazil (CNPQ) through grants 305159/2018-6 and 441971/2018-0. P. Silva is funded by Fundação para a Ciência e a Tecnologia (FCT), grant number SFRH/BD/146646/2019.</p>

scholarly journals Climate change, fire return intervals and the growing risk of permanent forest loss in boreal Eurasia

2021 ◽  
Author(s):  
Arden Burrell ◽  
Qiaoqi Sun ◽  
Robert Baxter ◽  
Elena Kukavskaya ◽  
Sergey Zhila ◽  
...  
Keyword(s):  
Climate Change ◽  
Boreal Forests ◽  
Fire Regime ◽  
Global Climate ◽  
Field Studies ◽  
Forest Loss ◽  
Burnt Area ◽  
Recruitment Failure ◽  
Extreme Risk ◽  
In Fire

Climate change has driven an increase in the frequency and severity of fires in Eurasian boreal forests. A growing number of field studies have linked the change in fire regime to post-fire recruitment failure and permanent forest loss. In this study we used four burnt area and two forest loss datasets to calculate the landscape-scale fire return interval (FRI) and associated risk of permanent forest loss. We then used machine learning to predict how the FRI will change under a high emissions scenario (SSP3-7.0) by the end of the century. We found that there is currently 133 000 km2 at high, or extreme, risk of fire-induced forest loss, with a further 3 M km2 at risk by the end of the century. This has the potential to degrade or destroy some of the largest remaining intact forests in the world, negatively impact the health and economic wellbeing of people living in the region, as well as accelerate global climate change.

Fire Regime of the Okefenokee Swamp and Its Relation to Hydrological and Climatic Conditions

1993 ◽  
Vol 3 (4) ◽  
pp. 229 ◽  
Author(s):  
ZY Yin
Keyword(s):  
Water Level ◽  
Management Practices ◽  
Fire Regime ◽  
Southern Oscillation ◽  
Climatic Conditions ◽  
Burnt Area ◽  
Enso Events ◽  
Okefenokee Swamp ◽  
Fire Activity ◽  
Complex Ecosystem

A fire record of the Okefenokee Swamp National Wildlife Refuge during the period 1938-1989 was examined in this study. Frequency analysis indicated that fires with burnt area 50% or more of the swamp area have return periods longer than 100 years, much longer than the previously assumed 20-25 year return period. Results of statistical analysis showed that fire activity is significantly related to die water level of the Okefenokee Swamp. Based on this relationship, a potential fire size can be estimated for a given water level. It seemed difficult to prove the link between the fire activity in the Okefenokee Swamp and the El Nino/Southern Oscillation (ENSO) events. However, further analysis revealed that the hydrological condition of the swamp is significantly related to the ENSO events. During the warm events, the Okefenokee Swamp area is wetter than normal; during the cold events, the area is drier than normal, and major fires tend to occur. The investigation of the fire regime may help achieve a better understanding of the effect of fires on the dynamics of this large complex ecosystem. The results are also useful for the refuge managers, especially in the mid- to long-term planning of fire management practices.

Fire history in relation to site type and vegetation in Vienansalo wilderness in eastern Fennoscandia, Russia

2004 ◽  
Vol 34 (7) ◽  
pp. 1400-1409 ◽  
Author(s):  
Tuomo H Wallenius ◽  
Timo Kuuluvainen ◽  
Ilkka Vanha-Majamaa
Keyword(s):  
Fire History ◽  
Fire Regime ◽  
Forest Type ◽  
Fire Frequency ◽  
Small Scale ◽  
Forest Patches ◽  
Burnt Area ◽  
Wilderness Area ◽  
In Fire ◽  
Scale Variation

A wildfire area in a boreal forest landscape dominated by Pinus sylvestris L., in the Vienansalo wilderness area in eastern Fennoscandia, was examined for its spatial characteristics and fire history. The boundaries of the 360-ha fire that occurred in 1969 were mapped, and the vegetation types of burnt and unburnt areas were inventoried. Fire history was investigated in 40 study plots, and fire scars, tree ages, and charcoal in peat or soil were used for evidence of past fires. The complex shape of the 1969 fire and the detected small-scale variation in past fire frequencies were concordant with the existing small-scale variation in site moisture and vegetation characteristics in the area. Moist depressions, swamps, and more fertile forest patches dominated by Picea abies (L.) Karst. often did not burn when the nearby dryish forest type did. There was also temporal variability in fire frequency. An abrupt increase in the number of fires occurred in the late 17th century. In the mid-19th century, both the number of fires and the annually burnt area in the region decreased. Our results show that in the examined wildfire area, there has been considerable and consistent small-scale spatial variation in fire frequency and that historical fire regime evidently has been strongly affected by human activity.

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