Mapped versus actual burned area within wildfire perimeters: Characterizing the unburned

Kolden, Crystal A.; Lutz, James A.; Key, Carl H.; Kane, Jonathan T.; Wagtendonk, Jan W. van

doi:10.1016/j.foreco.2012.08.020

Cited by 165 publications

(158 citation statements)

References 53 publications

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“…Accuracy of historical fire data decreases with age, due to both record-keeping and in that older methods of mapping wildfires often demonstrate considerable inaccuracies when compared to modern methods utilizing geospatial technologies [31,42,43]. Our spatial overlap of fire perimeter data assumes that all area within that perimeter burned; however, it is also widely acknowledged that, on average, up to 25% of the area within perimeters does not burn and remains as unburned islands [44][45][46].…”

Section: Limitationsmentioning

confidence: 99%

Spatial Distribution of Wildfires Ignited under Katabatic versus Non-Katabatic Winds in Mediterranean Southern California USA

Kolden

Abatzoglou

2018

Fire

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Wildfires are a major hazard to humans in the southern California Mediterranean ecosystem and improving our understanding and delineation of different fire regimes is critical to mitigating wildfire-related hazards. Recent research has demonstrated that there are two distinct fire regimes in this region based on the presence or absence of katabatic winds (primarily Santa Ana winds) concurrent with the fire. Here, we expand the katabatic wind category to include Sundowner winds along the Santa Barbara front range and analyze the spatial relationships and difference in ignition sources between fires associated with katabatic and non-katabatic wind events from 1948-2017. We found distinct spatial extents for katabatic versus non-katabatic fires, with areas of the higher number of repeat fires generally associated with one fire type or the other. These spatial delineations were consistent with prior analyses of katabatic wind patterns and were also related to the climatology of marine influences across the region. Finally, we contextualize the burn perimeter of the 2017 Thomas Fire, the largest fire in modern California history, relative to spatial patterns of katabatic and non-katabatic fires. The 2017 Thomas Fire began during the longest Santa Ana event in the last 70 years in an area that has been burned repeatedly by Santa Ana fires. However, the Thomas Fire ultimately burned into a region where there were no prior Santa Ana fires. The spatial delineation of two relatively distinct fire regimes is critical to making management decisions, such as where to locate suppression resources at critical times and where fuel treatments might be most effective. However, the anomalous pattern of the Thomas Fire also points to the potential for changes in anthropogenic and environmental factors to disrupt historical spatial patterns and suggests that spatial patterns of fire regimes are themselves prospective metrics of global change.

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Section: Limitationsmentioning

confidence: 99%

Spatial Distribution of Wildfires Ignited under Katabatic versus Non-Katabatic Winds in Mediterranean Southern California USA

Kolden

Abatzoglou

2018

Fire

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“…Unburned patches within a fire polygon are common [17,55,56] and can significantly alter the differential reflectance at 1 km resolution so that small unburned patches at 30 m resolution can be also considered as unburned at 1 km resolution. When comparing the most used global BA products, all products have been acknowledged to underestimate burned-area and that an increase in pixel size or burned patch elongation, results in larger estimation errors [48].…”

Section: Uncertain Boundaries and Patch Size Underestimationmentioning

confidence: 99%

Can We Go Beyond Burned Area in the Assessment of Global Remote Sensing Products with Fire Patch Metrics?

et al. 2016

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Global burned area (BA) datasets from satellite Earth observations provide information for carbon emission and for Dynamic Global Vegetation Model (DGVM) benchmarking. Fire patch identification from pixel-level information recently emerged as an additional way of providing informative features about fire regimes through the analysis of patch size distribution. We evaluated the ability of global BA products to accurately represent morphological features of fire patches, in the fire-prone Brazilian savannas. We used the pixel-level burned area from LANDSAT images, as well as two global products: MODIS MCD45A1 and the European Space Agency (ESA) fire Climate Change Initiative (FIRE_CCI) product for the 2002-2009 time period. Individual fire patches were compared by linear regressions to test the consistency of global products as a source of burned patch shape information. Despite commission and omission errors respectively reaching 0.74 and 0.81 for ESA FIRE_CCI and 0.64 and 0.62 for MCD45A1 when compared to LANDSAT due to missing small fires, correlations between patch areas showed R 2 > 0.6 for all comparisons, with a slope of 0.99 between ESA FIRE_CCI and MCD45A1 but a lower slope (0.6-0.8) when compared to the LANDSAT data. Shape complexity between global products was less correlated (R 2 = 0.5) with lower values (R 2 = 0.2) between global products and LANDSAT data, due to their coarser resolution. For the morphological features of the ellipse fitted over fire patches, R 2 reached 0.6 for the ellipse's eccentricity and varied from 0.4 to 0.8 for its azimuthal directional angle. We conclude that global BA products underestimate total BA as they miss small fires, but they also underestimate burned patch areas. Patch complexity is the least correlated variable, but ellipse features appear to provide information to be further used for quality product assessment, global pyrogeography or DGVM benchmarking.

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“…For this assessment, we included all area within fire perimeters. We recognize that there is substantial variability in burn severity, including unburned areas, within MTBS perimeters (Kolden et al 2012), but our goal was to assess all potential overlap with the similarly inclusive and coarseresolution insect polygon data.…”

Section: Fire Data From Monitoring Trends In Burn Severity (Mtbs)mentioning

confidence: 99%

“…Such a constrained approach may help to resolve the insect and non-insect components of our insect-fire likelihood matrix (Appendix D), but it would also reduce further any potential insect-fire overlap. Similarly, the MTBS fire perimeters contain a wide range of fire effectsincluding unburned or unburnable patches (Kolden et al 2012)-that could mask potential insect-fire signals. Future research could focus on how moderate-and high-severity fires are linked to insects and other potential drivers (e.g., climate; Kulakowski and Jarvis 2011).…”

Section: Uncertainties and Future Researchmentioning

confidence: 99%

Does wildfire likelihood increase following insect outbreaks in conifer forests?

et al. 2015

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Abstract. Although there is acute concern that insect-caused tree mortality increases the likelihood or severity of subsequent wildfire, previous studies have been mixed, with findings typically based on standscale simulations or individual events. This study investigates landscape-and regional-scale wildfire likelihood following outbreaks of the two most prevalent native insect pests in the US Pacific Northwest (PNW): mountain pine beetle (MPB; Dendroctonus ponderosae) and western spruce budworm (WSB; Choristoneura freemani). We leverage seamless census data across numerous insect and fire events to (1) summarize the interannual dynamics of insects and wildfires across forested ecoregions of the PNW; (2) identify potential linked disturbance interactions with an empirical wildfire likelihood index; (3) quantify this insect-fire likelihood across different insect agents, time lags, ecoregions, and fire sizes. All three disturbance agents have occurred primarily in the drier, interior conifer forests east of the Cascade Range. In general, WSB extent exceeds MPB extent, which in turn exceeds wildfire extent, and each disturbance typically affects less than 2% annually of a given ecoregion. In recent decades across the PNW, wildfire likelihood does not consistently increase or decrease following insect outbreaks. There is evidence, however, of linked interactions that vary across insect agent (MPB, WSB), space (ecoregion), and time (interval since insect onset). Specifically, in most cases following MPB activity, fire likelihood is neither higher nor lower than in non-MPB-affected forests. In contrast, fire likelihood is lower following WSB activity across multiple ecoregions and time lags. In addition, insect-fire likelihood is not consistently associated with interannual fire extent, suggesting that other factors (e.g., climate) control the disproportionately large fire years accounting for regional fire dynamics. Thus, although both bark beetles and defoliators alter fuels and associated fire potential, the windows of opportunity for increased or decreased fire likelihood are too narrow-or the phenomena themselves too rare-for a consistent signal to emerge across PNW conifer forests. These findings suggest that strategic plans should recognize (1) the relative rarity of insect-fire interactions and (2) the potential ecosystem restoration benefits of native insect outbreaks, when they do occur.

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Mapped versus actual burned area within wildfire perimeters: Characterizing the unburned

Cited by 165 publications

References 53 publications

Spatial Distribution of Wildfires Ignited under Katabatic versus Non-Katabatic Winds in Mediterranean Southern California USA

Spatial Distribution of Wildfires Ignited under Katabatic versus Non-Katabatic Winds in Mediterranean Southern California USA

Can We Go Beyond Burned Area in the Assessment of Global Remote Sensing Products with Fire Patch Metrics?

Does wildfire likelihood increase following insect outbreaks in conifer forests?

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