scholarly journals Grassification and Fast-Evolving Fire Connectivity and Risk in the Sonoran Desert, United States

2021 ◽  
Vol 9 ◽  
Author(s):  
Benjamin T. Wilder ◽  
Catherine S. Jarnevich ◽  
Elizabeth Baldwin ◽  
Joseph S. Black ◽  
Kim A. Franklin ◽  
...  
Keyword(s):  
United States ◽  
Sonoran Desert ◽  
Native Species ◽  
Fire Regimes ◽  
Fire Spread ◽  
Burned Area ◽  
Minor Role ◽  
Desert Grassland ◽  
Fire Dynamics ◽  
Native Grass

In the southwestern United States, non-native grass invasions have increased wildfire occurrence in deserts and the likelihood of fire spread to and from other biomes with disparate fire regimes. The elevational transition between desertscrub and montane grasslands, woodlands, and forests generally occurs at ∼1,200 masl and has experienced fast suburbanization and an expanding wildland-urban interface (WUI). In summer 2020, the Bighorn Fire in the Santa Catalina Mountains burned 486 km2 and prompted alerts and evacuations along a 40-km stretch of WUI below 1,200 masl on the outskirts of Tucson, Arizona, a metropolitan area of >1M people. To better understand the changing nature of the WUI here and elsewhere in the region, we took a multidimensional and timely approach to assess fire dynamics along the Desertscrub-Semi-desert Grassland ecotone in the Catalina foothills, which is in various stages of non-native grass invasion. The Bighorn Fire was principally a forest fire driven by a long-history of fire suppression, accumulation of fine fuels following a wet winter and spring, and two decades of hotter droughts, culminating in the hottest and second driest summer in the 125-yr Tucson weather record. Saguaro (Carnegia gigantea), a giant columnar cactus, experienced high mortality. Resprouting by several desert shrub species may confer some post-fire resiliency in desertscrub. Buffelgrass and other non-native species played a minor role in carrying the fire due to the patchiness of infestation at the upper edge of the Desertscrub biome. Coupled state-and-transition fire-spread simulation models suggest a marked increase in both burned area and fire frequency if buffelgrass patches continue to expand and coalesce at the Desertscrub/Semi-desert Grassland interface. A survey of area residents six months after the fire showed awareness of buffelgrass was significantly higher among residents that were evacuated or lost recreation access, with higher awareness of fire risk, saguaro loss and declining property values, in that order. Sustained and timely efforts to document and assess fast-evolving fire connectivity due to grass invasions, and social awareness and perceptions, are needed to understand and motivate mitigation of an increasingly fire-prone future in the region.

Fire spread from MODIS burned area data: obtaining fire dynamics information for every single fire

2016 ◽  
Vol 25 (12) ◽  
pp. 1228 ◽  
Author(s):  
David Frantz ◽  
Marion Stellmes ◽  
Achim Röder ◽  
Joachim Hill
Keyword(s):  
Large Scale ◽  
Fire Regimes ◽  
Fire Spread ◽  
Burned Area ◽  
Large Area ◽  
Fire Dynamics ◽  
Seed Point ◽  
Individual Object ◽  
The Individual ◽  
Area Data

Fire spread information on a large scale is still a missing key layer for a complete description of fire regimes. We developed a novel multilevel object-based methodology that extracts valuable information about fire dynamics from Moderate Resolution Imaging Spectroradiometer (MODIS) burned area data. Besides the large area capabilities, this approach also derives very detailed information for every single fire regarding timing and location of its ignition, as well as detailed directional multitemporal spread information. The approach is a top–down approach and a multilevel segmentation strategy is used to gradually refine the individual object membership. The multitemporal segmentation alternates between recursive seed point identification and queue-based fire tracking. The algorithm relies on only a few input parameters that control the segmentation with spatial and temporal distance thresholds. We present exemplary results that indicate the potential for further use of the derived parameters.

scholarly journals Non-native plants exert strong but under-studied influence on fire dynamics

NeoBiota ◽  
2020 ◽  
Vol 61 ◽  
pp. 47-64
Author(s):  
Clare E. Aslan ◽  
Brett G. Dickson
Keyword(s):  
Native Species ◽  
Native Plants ◽  
Meta Analysis ◽  
Fire Regimes ◽  
Fire Effects ◽  
Fire Dynamics ◽  
Feedback Cycle ◽  
Quantitative Studies ◽  
Significant Difference ◽  
The Relationship

Altered fire regimes are among the most destructive consequences of anthropogenic environmental change. Fires have increased in frequency in some regions, and invasion by fire-adapted non-native species has been identified as a major driver of this change, which results in a feedback cycle promoting further spread by the non-native species and diminishing occurrence of natives. We notice, however, that non-native species are often invoked in passing as a primary cause of changing fire dynamics, but that data supporting this claim are rarely presented. We therefore performed a meta-analysis of published literature to determine whether a significant relationship exists between non-native species presence and increased fire effects and risk, examined via various fire metrics. Our analysis detected a strongly significant difference between fire metrics associated with non-native and native species, with non-native species linked to enhanced fire effects and risk. However, only 30 papers discussing this linkage provided data to support it, and those quantitative studies examined only eight regions, five biome types, and a total of 22 unique non-native taxa. It is clear that we are only beginning to understand the relationship between non-native species and fire and that results drawn from an extremely limited set of contexts have been broadly applied in the literature. It is important for ecologists to continue to investigate drivers of changing fire regimes as factors such as climate change and land use change alter native and non-native fuels alike.

scholarly journals Warming enabled upslope advance in western US forest fires

2021 ◽  
Vol 118 (22) ◽  
pp. e2009717118
Author(s):  
Mohammad Reza Alizadeh ◽  
John T. Abatzoglou ◽  
Charles H. Luce ◽  
Jan F. Adamowski ◽  
Arvin Farid ◽  
...  
Keyword(s):  
United States ◽  
Forest Fires ◽  
Management Practices ◽  
Warm Season ◽  
Fire Regimes ◽  
High Elevation ◽  
Western United States ◽  
Burned Area ◽  
Climate Trends ◽  
Recent Climate

Increases in burned area and large fire occurrence are widely documented over the western United States over the past half century. Here, we focus on the elevational distribution of forest fires in mountainous ecoregions of the western United States and show the largest increase rates in burned area above 2,500 m during 1984 to 2017. Furthermore, we show that high-elevation fires advanced upslope with a median cumulative change of 252 m (−107 to 656 m; 95% CI) in 34 y across studied ecoregions. We also document a strong interannual relationship between high-elevation fires and warm season vapor pressure deficit (VPD). The upslope advance of fires is consistent with observed warming reflected by a median upslope drift of VPD isolines of 295 m (59 to 704 m; 95% CI) during 1984 to 2017. These findings allow us to estimate that recent climate trends reduced the high-elevation flammability barrier and enabled fires in an additional 11% of western forests. Limited influences of fire management practices and longer fire-return intervals in these montane mesic systems suggest these changes are largely a byproduct of climate warming. Further weakening in the high-elevation flammability barrier with continued warming has the potential to transform montane fire regimes with numerous implications for ecosystems and watersheds.

scholarly journals Response of simulated burned area to historical changes in environmental and anthropogenic factors: a comparison of seven fire models

2019 ◽  
Vol 16 (19) ◽  
pp. 3883-3910 ◽  
Author(s):  
Lina Teckentrup ◽  
Sandy P. Harrison ◽  
Stijn Hantson ◽  
Angelika Heil ◽  
Joe R. Melton ◽  
...  
Keyword(s):  
Land Use ◽  
Co2 Concentration ◽  
Fire Regimes ◽  
Atmospheric Co2 ◽  
Anthropogenic Factors ◽  
Burned Area ◽  
Earth System ◽  
Atmospheric Co2 Concentration ◽  
Fire Models ◽  
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 on simulated burned area, which are prescribed in the simulations. Specifically these drivers are atmospheric CO2 concentration, 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 1921. We analyse the trajectories of differences between the sensitivity and reference simulation to improve our understanding of what drives the global trends in burned area. Where it is possible, we link the inter-model differences to model assumptions. Overall, these analyses reveal that the largest uncertainties in simulating global historical burned area are related to the representation of anthropogenic ignitions and suppression and effects of land use on vegetation and fire. In line with previous studies this highlights the need to improve our understanding and model representation of the relationship between human activities and fire to improve our abilities to model fire within Earth system model applications. Only two models show a strong response to atmospheric CO2 concentration. The effects of changes in atmospheric CO2 concentration on fire are complex and quantitative information of how fuel loads and how flammability changes due to this factor is missing. The response to lightning on global scale is low. The response of burned area to climate is spatially heterogeneous and has a strong inter-annual variation. Climate is therefore likely more important than the other factors for short-term variations and extremes in burned area. This study provides a basis to understand the uncertainties in global fire modelling. Both improvements in process understanding and observational constraints reduce uncertainties in modelling burned area trends.

scholarly journals The Danger of Analogical Myths: Explaining the Power and Consequences of the Sykes-Picot Delusion

AJIL Unbound ◽  
2016 ◽  
Vol 110 ◽  
pp. 132-136 ◽  
Author(s):  
Toby Dodge
Keyword(s):  
United States ◽  
Middle East ◽  
The United States ◽  
Historical Background ◽  
Minor Role ◽  
Historical Significance ◽  
Historical Analogy ◽  
History Of ◽  
Political Units ◽  
Postcolonial States

Even before its hundredth year anniversary on 16 May 2016, the Sykes-Picot agreement had become a widely cited historical analogy both in the region itself and in Europe and the United States. In the Middle East, it is frequently deployed as an infamous example of European imperial betrayal and Western attempts more generally to keep the region divided, in conflict, and easy to dominate. In Europe and the United States, however, its role as a historical analogy is more complex—a shorthand for understanding the Middle East as irrevocably divided into mutually hostile sects and clans, destined to be mired in conflict until another external intervention imposes a new, more authentic, set of political units on the region to replace the postcolonial states left in the wake of WWI. What is notable about both these uses of the Sykes-Picot agreement is that they fundamentally misread, and thus overstate, its historical significance. The agreement reached by the British diplomat Mark Sykes and his French counterpart, François Georges-Picot, in May 1916, quickly became irrelevant as the realities on the ground in the Middle East, U.S. intervention into the war, a resurgent Turkey and the comparative weakness of the French and British states transformed international relations at the end of the First World War. Against this historical background, explaining the contemporary power of the narrative surrounding the use of the Sykes-Picot agreement becomes more intellectually interesting than its minor role in the history of European imperial interventions in the Middle East.

Fine-Scale Fire Spread in Pine Straw

Fire ◽  
2021 ◽  
Vol 4 (4) ◽  
pp. 69
Author(s):  
Daryn Sagel ◽  
Kevin Speer ◽  
Scott Pokswinski ◽  
Bryan Quaife
Keyword(s):  
Fire Spread ◽  
Small Scale ◽  
Natural Setting ◽  
Fine Scale ◽  
Prescribed Burn ◽  
Fire Dynamics ◽  
Rate Of Spread ◽  
Scale Models ◽  
Fire Front ◽  
Visible Images

Most wildland and prescribed fire spread occurs through ground fuels, and the rate of spread (RoS) in such environments is often summarized with empirical models that assume uniform environmental conditions and produce a unique RoS. On the other hand, representing the effects of local, small-scale variations of fuel and wind experienced in the field is challenging and, for landscape-scale models, impractical. Moreover, the level of uncertainty associated with characterizing RoS and flame dynamics in the presence of turbulent flow demonstrates the need for further understanding of fire dynamics at small scales in realistic settings. This work describes adapted computer vision techniques used to form fine-scale measurements of the spatially and temporally varying RoS in a natural setting. These algorithms are applied to infrared and visible images of a small-scale prescribed burn of a quasi-homogeneous pine needle bed under stationary wind conditions. A large number of distinct fire front displacements are then used statistically to analyze the fire spread. We find that the fine-scale forward RoS is characterized by an exponential distribution, suggesting a model for fire spread as a random process at this scale.

Spatial patterns of fire patch size and shape complexity in the Brazilian savanna

2021 ◽  
Author(s):  
Joana Nogueira ◽  
Julia Rodrigues ◽  
Jan Lehmann ◽  
Hanna Meyer ◽  
Renata Libonati
Keyword(s):  
Land Use ◽  
Shape Index ◽  
Fire Spread ◽  
Core Area ◽  
Validation Dataset ◽  
Burned Area ◽  
Fire Size ◽  
Size And Shape ◽  
The North ◽  
Shape Complexity

<p>Fire events on a landscape scale are a widespread global phenomenon that influences the interactions between atmosphere and biosphere. Global burned area (BA) products derived from satellite images are used in dynamic vegetation fire modules to estimate greenhouse gas emissions, available fuel biomass and anthropic factors driving fire spread. Fire size and shape complexity from individual fire events can provide better estimates of fuel consumption, fire intensity, post fire vegetation recovery and their effects on landscape changes to better understand regional fire dynamics. Especially in the Brazilian savannas (Cerrado), a mosaic of heterogeneous vegetation where has prevailed an official “zero-fire” policy for decades leading to an increase in large wildfires, intensified also by rapid changes of land use using fire to land clearing in agriculture and livestock purposes. In this way, we aim to assess the fire size and shape patterns in Cerrado from 2013 to 2015, identifying each fire patch event from Landsat BA product and calculating its fire features with landscape metrics. We calculated its surface area to evaluate fire size and the metrics of shape index, core area and eccentricity from an ellipse fitting from burned pixels to estimate the fire shape complexity. The study focused on 48 Landsat path/row scenes and the analysis final compared the fire features of overlapped patches between the years. The total number of coincident fire patches is higher between the years 2013 and 2015 than 2013-2014 and 2014-2015. Large fires are found in the north and east regions for all comparisons. In this region, high core area values are consistent for having large areas of burnt patches and low shape index values and more elongated patches revealed a low fire shape complexity. These results demonstrate a greater burned area in the north, where the remaining native vegetation and less fragmented landscapes allow the fire to spread, when associated with favorable meteorological conditions. However, with the implementation of a new agricultural frontier in 2015, this region is under greater anthropic pressure with positive trends to land use. In the south, the fire shapes are already more complex and smaller because they are from agricultural areas historically developed, and consequently the landscape is more fragmented. Our results demonstrate a distinct spatial pattern of fire shape and size in Cerrado related to fragmentation of landscape and fire use to land cleaning. This information can help the modelling estimates of fire spread processes driven by topography, orientation of watersheds or dominant winds at local level, contributing to understanding the feedback with land cover/use, climate and biophysical characteristics at regional level to develop strategies for fire management.</p><p><strong>Acknowledges:</strong> J.N is funded by the 'Women in Research'-fellowship program (WWU Münster) and within the context of BIOBRAS Project “Research-based learning in neglected biodiverse ecosystems of Brazil”; funding by DAAD (number 57393735); validation dataset was performed under the Andurá project (number 441971/2018–0) funding by CNPq</p>

scholarly journals A VIIRS direct broadcast algorithm for rapid response mapping of wildfire burned area in the western United States

2018 ◽  
Vol 219 ◽  
pp. 271-283 ◽  
Author(s):  
Shawn Urbanski ◽  
Bryce Nordgren ◽  
Carl Albury ◽  
Brenna Schwert ◽  
David Peterson ◽  
...  
Keyword(s):  
United States ◽  
Rapid Response ◽  
Western United States ◽  
Burned Area ◽  
Response Mapping ◽  
Direct Broadcast

scholarly journals Comparing modelled fire dynamics with charcoal records for the Holocene

2014 ◽  
Vol 10 (2) ◽  
pp. 811-824 ◽  
Author(s):  
T. Brücher ◽  
V. Brovkin ◽  
S. Kloster ◽  
J. R. Marlon ◽  
M. J. Power
Keyword(s):  
Land Surface ◽  
Burned Area ◽  
Surface Model ◽  
Model Output ◽  
Z Score ◽  
Fire Dynamics ◽  
Anthropogenic Forcing ◽  
Natural Fire ◽  
Fire Activity ◽  
Z Scores

Abstract. An earth system model of intermediate complexity (CLIMate and BiosphERe – CLIMBER-2) and a land surface model (JSBACH), which dynamically represent vegetation, are used to simulate natural fire dynamics through the last 8000 yr. Output variables of the fire model (burned area and fire carbon emissions) are used to compare model results with sediment-based charcoal reconstructions. Several approaches for processing model output are also tested. Charcoal data are reported in Z-scores with a base period of 8000–200 BP in order to exclude the strong anthropogenic forcing of fire during the last two centuries. The model–data comparison reveals a robust correspondence in fire activity for most regions considered, while for a few regions, such as Europe, simulated and observed fire histories show different trends. The difference between modelled and observed fire activity may be due to the absence of anthropogenic forcing (e.g. human ignitions and suppression) in the model simulations, and also due to limitations inherent to modelling fire dynamics. The use of spatial averaging (or Z-score processing) of model output did not change the directions of the trends. However, Z-score-transformed model output resulted in higher rank correlations with the charcoal Z-scores in most regions. Therefore, while both metrics are useful, processing model output as Z-scores is preferable to areal averaging when comparing model results to transformed charcoal records.

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