Megafires in Chile 2017: Monitoring multiscale environmental impacts of burned ecosystems

Barrera, Francisco de la; Barraza, Francisco; Favier, Philomène; Ruiz, Vannia; Qüense, Jorge

doi:10.1016/j.scitotenv.2018.05.119

Cited by 118 publications

(86 citation statements)

References 49 publications

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“…Regeneration in burned areas is mainly controlled by burn severity and basal area, with influences of topography and biotic interactions, but fire refugia also play a role as seed sources for post-fire dynamics in the longer term [42]. As an important driver of the dynamics of these forests, burn severity is generally assessed in the ecological studies of fire events [43][44][45]. However, field-validation of burn severity mapping methodologies for Patagonian forests is scarce [46].…”

Section: Introductionmentioning

confidence: 99%

Field-Validated Burn-Severity Mapping in North Patagonian Forests

2020

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Burn severity, which can be reliably estimated by validated spectral indices, is a key element for understanding ecosystem dynamics and informing management strategies. However, in North Patagonian forests, where wildfires are a major disturbance agent, studies aimed at the field validation of spectral indices of burn severity are scarce. The aim of this work was to develop a field validated methodology for burn-severity mapping by studying two large fires that burned in the summer of 2013–2014 in forests of Araucaria araucana and other tree species. We explored the relation between widely used spectral indices and a field burn-severity index, and we evaluated index performance by examining index sensitivity in discriminating burn-severity classes in different vegetation types. For those indices that proved to be suitable, we adjusted the class thresholds and constructed confusion matrices to assess their accuracy. Burn severity maps of the studied fires were generated using the two most accurate methods and were compared to evaluate their level of agreement. Our results confirm that reliable burn severity estimates can be derived from spectral indices for these forests. Two severity indices, the delta normalized burn ratio (dNBR) and delta normalized difference vegetation index (dNDVI), were highly related to the fire-induced changes observed in the field, but the strength of these associations varied across the five different vegetation types defined by tree heights and tree and tall shrub species regeneration strategies. The thresholds proposed in this study for these indices generated classifications with global accuracies of 82% and Kappa indices of 70%. Both the dNBR and dNDVI classification approaches were more accurate in detecting high severity, but to a lesser degree for detecting low severity burns. Moderate severity was poorly classified, with producer and user errors reaching 50%. These constraints, along with detected differences in separability, need to be considered when interpreting burn severity maps generated using these methods.

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Section: Introductionmentioning

confidence: 99%

Field-Validated Burn-Severity Mapping in North Patagonian Forests

2020

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“…Besides meteorology, advection of a PM plume over the city could be a candidate cause for such events. For instance, wildfires occurring in the forests surrounding the city occasionally explain major peaks of particulate matter in Santiago (Rubio et al, 2015;de la Barrera et al, 2018), but these events mostly take place in austral summer, and no such event was reported during our period of study. In addition, the strong concentration gradients observed between nearby stations ( Fig.…”

Section: Pm 25 Peaks Descriptionmentioning

confidence: 70%

Soccer games and record-breaking PM2.5 pollution events in Santiago, Chile

Lapere¹,

Menut²,

Mailler³

et al. 2019

Preprint

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Abstract. In wintertime, high background concentrations of atmospheric fine particulate matter (PM2.5) are commonly observed in the metropolitan area of Santiago, Chile. Hourly peaks can be very strong, up to ten times average levels, but have barely been studied so far. Based on atmospheric composition measurements and chemistry-transport modeling (WRF-CHIMERE), the chemical signature of sporadic skyrocketing wintertime PM2.5 peaks is analyzed. This signature and the timing of such extreme events traces their origin back to massive barbecue cooking by Santiago's inhabitants during international soccer games. The peaks end up evacuated outside Santiago after a few hours but trigger emergency plans for the next day. Decontamination plans in Santiago focus on decreasing traffic, industrial and residential heating emissions. Thanks to the air quality network of Santiago, this study shows that cultural habits such as barbecue cooking also need to be taken into account. For short-term forecast and emergency management, cultural events such as soccer games seem a good proxy to prognose possible PM2.5 peak events. Not only this result can have an informative value for the Chilean authorities, but a similar methodology could also be reproduced for other cases throughout the world in order to estimate the burden on air quality of cultural habits. In particular, the present study shows that investigating the atmospheric composition in large cities during major events is key for the design of effective air pollution mitigation policies.

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“…Although several studies addressed fire risk of large fires and mega-fires (e.g. Attiwill and Adams 2013;de la Barrera et al 2018;Williams 2013), the use of different fire size ranges in Mediterranean areas for analysis and modelling is still an approach seldom proposed. In this line, a similar study in Portugal (Moreira et al 2010) utilized size classes to explore Fig.…”

Section: Discussionmentioning

confidence: 99%

Size dependency of variables influencing fire occurrence in Mediterranean forests of Eastern Spain

Peris-Llopis

Mola‐Yudego

2020

Eur J Forest Res

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Fires are among the most damaging disturbances to forests in the Mediterranean area. The study analyses the occurrence and characteristics of forest fires in Eastern Spain to identify key variables related to burnt forest land, differentiating fires according to their burnt area. Data are retrieved from digital cartography, the Spanish Forest Map and data concerning fires. Based on previous research, the variables included are altitude, slope, aspect, fuel, species, population and road density. The fires are classified in small (5-50 ha), medium (50-500 ha) and large (> 500 ha). Four models are considered to explain the proportion of burnt area based on weighted generalized linear models: a general model and one per size class. The results highlight the different relations of similar variables with fires according to the size. When a single model is considered to explain all area burnt, the relationships are mainly driven by large fires. The larger area is burnt on forests with pine, bushes and small trees, whereas smaller fires tend to occur on lower altitude, low slope, high population and road densities. There are large differences in the variables according to the fire sizes, especially for the presence of pine (negative in the medium fires model but positive for the large fires model) and Pasture (which only explains the small fires). The models can be applied to analyse occurrence by fire size in Mediterranean areas, and the results can help elaborate fire prevention strategies and land-planning schemes.

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Megafires in Chile 2017: Monitoring multiscale environmental impacts of burned ecosystems

Cited by 118 publications

References 49 publications

Field-Validated Burn-Severity Mapping in North Patagonian Forests

Field-Validated Burn-Severity Mapping in North Patagonian Forests

Soccer games and record-breaking PM<sub>2.5</sub> pollution events in Santiago, Chile

Size dependency of variables influencing fire occurrence in Mediterranean forests of Eastern Spain

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Megafires in Chile 2017: Monitoring multiscale environmental impacts of burned ecosystems

Cited by 118 publications

References 49 publications

Field-Validated Burn-Severity Mapping in North Patagonian Forests

Field-Validated Burn-Severity Mapping in North Patagonian Forests

Soccer games and record-breaking PM&lt;sub&gt;2.5&lt;/sub&gt; pollution events in Santiago, Chile

Size dependency of variables influencing fire occurrence in Mediterranean forests of Eastern Spain

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Product

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Soccer games and record-breaking PM<sub>2.5</sub> pollution events in Santiago, Chile