Responses of Plant Biomass in the Brazilian Savanna to Frequent Fires

Fire has been a natural feature of the ecosystem for million years. Still, currently fire regimes have been increasingly altered by human activities and climate change, causing economic losses, air pollution, and environmental damage. In Brazil, savannas (locally known as the Cerrado) occupy almost 25% of the area of the country and contain 70% of the concentrated burned area. Fire frequency is related to the use of biannual fire in agricultural practices, aiming at cleaning cattle pastures, which act as ignition sources for the surrounding natural vegetation. Here, we present an ecological model to demonstrate how biennial fire affects plant biomass and carbon release from fine fuel in the Cerrado. The BEFIRE model (Behavior and Effect of Fire) is the first quantitative model to simulate the relationships between fire frequency, plant biomass, and fire-associated emissions based on the synthesis of knowledge about fire behavior and the effects on ecosystems compiled from experimental burnings in the Cerrado. Our model uses microclimate variables and vegetation structure (the amount of the aboveground biomass of trees, shrubs, herbs, and grasses) as inputs, and generates outputs related to the fire behavior (fire spread rate, fire intensity, and heat released) and the fire effects on the dynamic of plant biomass and post-fire carbon emissions. The BEFIRE model predicts that biennial fires allow for the recovery of the biomass of herbs and grasses, due to its fast growth. However, this fire interval does not allow for the recovery of the biomass of shrubs and trees. These growth limitations alter the co-existence of trees/shrubs and herbs/grasses and prevent the uptake of the total amount of emitted carbon from the combustion of fine fuel. Based on the model results, we proposed some recommendations for fire management in this threatened biome.

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Unmanned Aerial Vehicles for Wildland Fires: Sensing, Perception, Cooperation and Assistance

Drones ◽

10.3390/drones5010015 ◽

2021 ◽

Vol 5 (1) ◽

pp. 15

Author(s):

Moulay A. Akhloufi ◽

Andy Couturier ◽

Nicolás A. Castro

Keyword(s):

Unmanned Aerial Vehicles ◽

Wildland Fire ◽

Fire Intensity ◽

Economic Losses ◽

Small Scale ◽

Environmental Damage ◽

Unmanned Aerial Systems ◽

Wildland Fires ◽

Natural Risk ◽

Aerial Vehicles

Wildfires represent a significant natural risk causing economic losses, human death and environmental damage. In recent years, the world has seen an increase in fire intensity and frequency. Research has been conducted towards the development of dedicated solutions for wildland fire assistance and fighting. Systems were proposed for the remote detection and tracking of fires. These systems have shown improvements in the area of efficient data collection and fire characterization within small-scale environments. However, wildland fires cover large areas making some of the proposed ground-based systems unsuitable for optimal coverage. To tackle this limitation, unmanned aerial vehicles (UAV) and unmanned aerial systems (UAS) were proposed. UAVs have proven to be useful due to their maneuverability, allowing for the implementation of remote sensing, allocation strategies and task planning. They can provide a low-cost alternative for the prevention, detection and real-time support of firefighting. In this paper, previous works related to the use of UAV in wildland fires are reviewed. Onboard sensor instruments, fire perception algorithms and coordination strategies are considered. In addition, some of the recent frameworks proposing the use of both aerial vehicles and unmanned ground vehicles (UGV) for a more efficient wildland firefighting strategy at a larger scale are presented.

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

10.5194/bg-2019-42 ◽

2019 ◽

Cited By ~ 1

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.

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Fire Frequency and Related Land-Use and Land-Cover Changes in Indonesia’s Peatlands

Remote Sensing ◽

10.3390/rs12010005 ◽

2019 ◽

Vol 12 (1) ◽

pp. 5 ◽

Cited By ~ 5

Author(s):

Yenni Vetrita ◽

Mark A. Cochrane

Keyword(s):

Land Use ◽

Land Cover ◽

Fire Regimes ◽

Fire Frequency ◽

Burned Area ◽

Swamp Forest ◽

Lulc Change ◽

Surface Areas ◽

Moderate Resolution ◽

Moderate Resolution Imaging Spectroradiometer

Indonesia’s converted peatland areas have a well-established fire problem, but limited studies have examined the frequency with which they are burning. Here, we quantify fire frequency in Indonesia’s two largest peatland regions, Sumatra and Kalimantan, during 2001–2018. We report, annual areas burned, total peatland area affected by fires, amount of recurrent burning and associations with land-use and land-cover (LULC) change. We based these analyses on Moderate Resolution Imaging Spectroradiometer (MODIS) Terra/Aqua combined burned area and three Landsat-derived LULC maps (1990, 2007, and 2015) and explored relationships between burning and land-cover types. Cumulative areas burned amounted nearly half of the surface areas of Sumatra and Kalimantan but were concentrated in only ~25% of the land areas. Although peatlands cover only 13% of Sumatra and Kalimantan, annual percentage of area burning in these areas was almost five times greater than in non-peatlands (2.8% vs. 0.6%) from 2001 to 2018. Recurrent burning was more prominent in Kalimantan than Sumatra. Average fire-return intervals (FRI) in peatlands of both regions were short, 28 and 45 years for Kalimantan and Sumatra, respectively. On average, forest FRI were less than 50 years. In non-forest areas, Kalimantan had shorter average FRI than Sumatra (13 years vs. 40 years), with ferns/low shrub areas burning most frequently. Our findings highlight the significant influence of LULC change in altering fire regimes. If prevalent rates of burning in Indonesia’s peatlands are not greatly reduced, peat swamp forest will disappear from Sumatra and Kalimantan in the coming decades.

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Modelling spatiotemporal variability in fires in semiarid savannas: a satellite-based assessment around Africa’s largest protected area

International Journal of Wildland Fire ◽

10.1071/wf15152 ◽

2016 ◽

Vol 25 (7) ◽

pp. 730 ◽

Cited By ~ 5

Author(s):

Niti B. Mishra ◽

Kumar P. Mainali ◽

Kelley A. Crews

Keyword(s):

Land Use ◽

Protected Areas ◽

Negative Binomial ◽

Null Model ◽

Fire Regimes ◽

Fire Frequency ◽

Spatiotemporal Variability ◽

Burned Area ◽

Vegetation Types ◽

Variance Explained

The relative importance of various drivers of fire regimes in savanna ecosystems can be location-specific. We utilised satellite-derived time-series burned area (2001–13) to examine how spatiotemporal variations in burned area and fire frequency were determined by rainfall, vegetation morphology and land use in semiarid savanna. Mean precipitation of the rainy season (Nov–Apr) had a strong and positive relationship with burned area in the following dry season (variance explained 63%), with the relationship being strongest inside protected areas (variance explained 73%). Burned area and fire frequency were higher in vegetation types with higher herbaceous cover, indicating a causal link between herbaceous load and fire. Among land use, fire frequency was highest in protected areas and lowest in farms and ranches. Spatial models (generalised linear models with Poisson and negative binomial distribution) accounting for spatial autocorrelation showed that land-use classes and vegetation types together explained approximately half of the deviance in null model (48%). Existence of fences and boreholes resulted in finer-scale spatial differences in fire frequency. There was minimal dependence of vegetation types on land-use classes in determining fire frequency (interaction between the two predictors was minimal). These results have significant implications for understanding drivers of fire activity in savanna ecosystems.

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Managing the human component of fire regimes: lessons from Africa

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2015.0346 ◽

2016 ◽

Vol 371 (1696) ◽

pp. 20150346 ◽

Cited By ~ 56

Author(s):

Sally Archibald

Keyword(s):

Human Impacts ◽

Ghg Emissions ◽

Fire Regimes ◽

Fire Frequency ◽

Time Of Day ◽

Fire Intensity ◽

Global Perspectives ◽

Fire Emissions ◽

Fire Characteristics ◽

Human Component

Human impacts on fire regimes accumulated slowly with the evolution of modern humans able to ignite fires and manipulate landscapes. Today, myriad voices aim to influence fire in grassy ecosystems to different ends, and this is complicated by a colonial past focused on suppressing fire and preventing human ignitions. Here, I review available evidence on the impacts of people on various fire characteristics such as the number and size of fires, fire intensity, fire frequency and seasonality of fire in African grassy ecosystems, with the intention of focusing the debate and identifying areas of uncertainty. Humans alter seasonal patterns of fire in grassy systems but tend to decrease total fire emissions: livestock have replaced fire as the dominant consumer in many parts of Africa, and fragmented landscapes reduce area burned. Humans alter the season and time of day when fires occur, with important implications for fire intensity, tree–grass dynamics and greenhouse gas (GHG) emissions. Late season fires are more common when fire is banned or illegal: these later fires are far more intense but emit fewer GHGs. The types of fires which preserve human livelihoods and biodiversity are not always aligned with the goal of reducing GHG concentrations. Current fire management challenges therefore involve balancing the needs of a large rural population against national and global perspectives on the desirability of different types of fire, but this cannot happen unless the interests of all parties are equally represented. In the future, Africa is expected to urbanize and land use to intensify, which will imply different trajectories for the continent's fire regimes. This article is part of the themed issue ‘The interaction of fire and mankind.

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Contradictions and Continuities: A Historical Context to Euro-American Settlement Era Fires of the Lake States, USA.

10.21203/rs.3.rs-925576/v1 ◽

2021 ◽

Author(s):

Jed Meunier

Keyword(s):

Land Use ◽

Land Use Changes ◽

Historical Context ◽

Fire Behavior ◽

Fire Frequency ◽

Burned Area ◽

Fire Scar ◽

Large Fires ◽

Lake States ◽

Historical Accounts

Abstract BackgroundThe Lake States experienced unprecedented land use changes during Euro-American settlement (settlement) including large, destructive fires. Forest changes were radical in this region and largely attributed to anomalous settlement era fires in slash (cumulation of tops and branches) following cutover logging. In this study I place settlement era fires in a historical context by examining fire scar data in comparison to historical accounts and investigate fire-vegetation-climate relationships within a 400-year context.ResultsSettlement era fires (1851–1947) were less frequent than historical fires (1548–1850) with little evidence that slash impacted fire frequency or occurrence at site or ecoregion scales. Only one out of 25 sites had more frequent settlement era fires and that site was a pine forest that had never been harvested. Settlement era fires were similar across disparate ecoregions and forest types including in areas with very different land use history. Settlement fires tended to burn during significantly dry periods, the same conditions driving large fires for the past 400 years. The burned area in the October 8, 1871 Peshtigo Fire was comprised of mesic forests where fuels were always abundant and high-severity fires would be expected given the conditions in 1871. Furthermore, slash would not have been a major contributor to fire behavior or effects in the Peshtigo Fire.ConclusionsHistorical records, like written accounts of fires and settlement era survey records, provide a reference point for landscape changes but lack temporal depth to understand forest dynamics or provide a mechanistic understanding of changes. While settlement land use changes of Lake States forests were pervasive, fires were not the ultimate degrading factor, but rather likely one of the few natural processes still at work.

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Distinguishing disturbance from perturbations in fire-prone ecosystems

International Journal of Wildland Fire ◽

10.1071/wf18203 ◽

2019 ◽

Vol 28 (4) ◽

pp. 282 ◽

Cited By ~ 15

Author(s):

Jon E. Keeley ◽

Juli G. Pausas

Keyword(s):

Fire Regime ◽

Natural Disturbance ◽

Fire Regimes ◽

Fire Frequency ◽

Fire Intensity ◽

Ecosystem Process ◽

Type Conversion ◽

Vegetation Shifts ◽

In Fire ◽

Historical Range

Fire is a necessary ecosystem process in many biomes and is best viewed as a natural disturbance that is beneficial to ecosystem functioning. However, increasingly, we are seeing human interference in fire regimes that alters the historical range of variability for most fire parameters and results in vegetation shifts. Such perturbations can affect all fire regime parameters. Here, we provide a brief overview of examples where anthropogenically driven changes in fire frequency, fire pattern, fuels consumed and fire intensity constitute perturbations that greatly disrupt natural disturbance cycles and put ecosystems on a different trajectory resulting in type conversion. These changes are not due to fire per se but rather anthropogenic perturbations in the natural disturbance regime.

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Fuel loads, fire regimes, and post-fire fuel dynamics in Florida Keys pine forests

International Journal of Wildland Fire ◽

10.1071/wf05100 ◽

2006 ◽

Vol 15 (4) ◽

pp. 463 ◽

Cited By ~ 28

Author(s):

Jay P. Sah ◽

Michael S. Ross ◽

James R. Snyder ◽

Suzanne Koptur ◽

Hillary C. Cooley

Keyword(s):

Fire Behavior ◽

Florida Keys ◽

Fire Regimes ◽

Life Forms ◽

Pine Forests ◽

Fire Intensity ◽

Fuel Type ◽

Fuel Loads ◽

Fuel Dynamics ◽

Fuel Components

In forests, the effects of different life forms on fire behavior may vary depending on their contributions to total fuel loads. We examined the distribution of fuel components before fire, their effects on fire behavior, and the effects of fire on subsequent fuel recovery in pine forests within the National Key Deer Refuge in the Florida Keys. We conducted a burning experiment in six blocks, within each of which we assigned 1-ha plots to three treatments: control, summer, and winter burn. Owing to logistical constraints, we burned only 11 plots, three in winter and eight in summer, over a 4-year period from 1998 to 2001. We used path analysis to model the effects of fuel type and char height, an indicator of fire intensity, on fuel consumption. Fire intensity increased with surface fuel loads, but was negatively related to the quantity of hardwood shrub fuels, probably because these fuels are associated with a moist microenvironment within hardwood patches, and therefore tend to resist fire. Winter fires were milder than summer fires, and were less effective at inhibiting shrub encroachment. A mixed seasonal approach is suggested for fire management, with burns applied opportunistically under a range of winter and summer conditions, but more frequently than that prevalent in the recent past.

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A century of transformation: Fire regime transitions from 1919 to 2019 in southeastern British Columbia, Canada

10.31219/osf.io/qhtcj ◽

2021 ◽

Author(s):

Jennifer N Baron ◽

Sarah E. Gergel ◽

Paul F. Hessburg ◽

Lori D. Daniels

Keyword(s):

British Columbia ◽

Fire Regime ◽

Fire Suppression ◽

Fire Regimes ◽

Fire Frequency ◽

Burned Area ◽

Annual Number ◽

Fire Size ◽

Climatic Period ◽

Fire Exclusion

The past 100 years marks a transition between pre-colonial and modern era fire regimes, which provides crucial context for understanding future wildfire behavior. Using the greatest depth of digitized fire events in Canada, we identify distinct phases of wildfire regimes from 1919 to 2019 by evaluating changes in mapped fire perimeters (>20-ha) across the East Kootenay forest region (including the southern Rocky Mountain Trench), British Columbia (BC). We detect transitions in annual number of fires, burned area, and fire size; explore the roles of lightning- and human-caused fires in driving these transitions; and quantify departures from historical fire frequency at the regional level. We found that, relative to historical fire frequency, fire exclusion created a significant fire deficit across 89% of the flammable landscape. Fire was active from 1919 to 1940 with frequent and large fire events, but the regime was already altered by a century of colonization. Fire activity decreased after 1940, coinciding with effective fire suppression influenced by a mild climatic period. After 2003, the combined effects of fire exclusion and accelerated climate change fueled a shift in fire regimes of various forest types, with increases in area burned and mean fire size driven by lightning.

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A spatial and temporal assessment of fire regimes on different vegetation types using MODIS burnt area products

Bothalia ◽

10.4102/abc.v46i2.2148 ◽

2016 ◽

Vol 46 (2) ◽

Cited By ~ 3

Author(s):

Nokuphila L.S. Buthelezi ◽

Onisimo Mutanga ◽

Mathieu Rouget ◽

Mbulisi Sibanda

Keyword(s):

Vegetation Type ◽

Fire Regimes ◽

Fire Frequency ◽

Fire Season ◽

Burned Area ◽

Vegetation Types ◽

Remotely Sensed Data ◽

Burnt Area ◽

Coastal Belt ◽

Kwazulu Natal

Background: The role of fire in maintaining grassland diversity has been widely recognised; however, its effect in KwaZulu-Natal grasslands is still rudimentary. In that regard, understanding fire regimes of different vegetation types in KwaZulu-Natal is a critical step towards the development of effective management strategies that are specific to each vegetation type. Objective: To assess the effect of different vegetation types on fire regimes in KwaZulu-Natal using moderate resolution imaging spectroradiometer (MODIS) burnt fire products. Method: Ten years of fire data for four different vegetation types (Ngongoni Veld, KwaZuluNatal Sandstone Sourveld, Eastern Valley Bushveld and KwaZulu-Natal Coastal Belt) were extracted from the MODIS products and used as a basis to establish three parameters: annual burnt areas, fire season and fire frequency. The total burnt area within each vegetation type over the 10-year period was quantified. Results: The KZN Sandstone Sourveld had a high-burnt area of 80% in 2009 with KwaZuluNatal Coastal Belt having the least burnt area of less than 5%. Ngongoni Veld and the KwaZuluNatal Sandstone Sourveld had the highest fire frequency, while the coastal region had low fire frequencies. Results showed high fire prevalence during the late period of the dry season (which extends from June to August) across all the vegetation types. Conclusion: This study underscores the potential of remotely sensed data (MODIS burned area products) in providing a comprehensive view of fire patterns in different vegetation types

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