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Background: Wildfires have caused significant damage in Chile, with critical infrastructure being vulnerable to extreme wildfires. Aim: This work describes a methodology for estimating wildfire risk that was applied to an electrical substation in the wildland–urban interface (WUI) of Valparaíso, Chile. Methods: Wildfire risk is defined as the product between the probability of a wildfire reaching infrastructure at the WUI and its consequences or impacts. The former is determined with event trees combined with modelled burn probability. Wildfire consequence is considered as the ignition probability of a proxy fuel within the substation, as a function of the incident heat flux using a probit expression derived from experimental data. The heat flux is estimated using modelled fire intensity and geometry and a corresponding view factor from an assumed solid flame. Key results: The probability of normal and extreme fires reaching the WUI is of the order of 10−4 and 10−6 events/year, respectively. Total wildfire risk is of the order of 10−5 to 10−4 events/year Conclusions: This methodology offers a comprehensive interpretation of wildfire risk that considers both wildfire likelihood and consequences. Implications: The methodology is an interesting tool for quantitatively assessing wildfire risk of critical infrastructure and risk mitigation measures. A methodology offering a comprehensive interpretation of wildfire risk considering both wildfire likelihood and asset vulnerability is proposed. The former is estimated with an event tree, while the latter is considered as the ignition probability of a polymeric fuel within a critical infrastructure. Wildfire risk is ~10−4 events/year. This article belongs to the Collection ICFFR. [ABSTRACT FROM AUTHOR]

It is generally expected that spatial planning integrates wildfire risk reduction considerations in areas affected by this hazard. However, many spatial planning systems are challenged to adequately deal with this risk. There is a need for applied understandings of planning systems characteristics that facilitate or impede wildfire risk reduction. Accordingly, this research explores spatial planning limitations to the integration of wildfire risk reduction measures by comparing spatial planning and wildfire risk reduction measures based on five key dimensions: structure, realm, spatial scale, territorial boundaries, and time scale. The research used a qualitative case study strategy of the Chilean spatial planning system, employing qualitative content analysis of key documents. The results show that the long-established characteristics of Chile's spatial planning limit its ability to accommodate wildfire risk reduction measures in the five dimensions analyzed. The research contributes to understanding some of spatial planning's constraints to manage wider complex challenges. [ABSTRACT FROM AUTHOR]

Wildfire risk is latent in Chilean metropolitan areas characterized by the strong presence of wildland–urban interfaces (WUIs). The Concepción metropolitan area (CMA) constitutes one of the most representative samples of that dynamic. The wildfire risk in the CMA was addressed by establishing a model of five categories (near zero, low, moderate, high, and very high) that represent discernible thresholds in fire occurrence, using geospatial data and satellite images describing anthropic–biophysical factors that trigger fires. Those were used to deliver a model of fire hazard using machine learning algorithms, including principal component analysis and Kohonen self-organizing maps in two experimental scenarios: only native forest and only forestry plantation. The model was validated using fire hotspots obtained from the forestry government organization. The results indicated that 12.3 % of the CMA's surface area has a high and very high risk of a forest fire, 29.4 % has a moderate risk, and 58.3 % has a low and very low risk. Lastly, the observed main drivers that have deepened this risk were discussed: first, the evident proximity between the increasing urban areas with exotic forestry plantations and, second, climate change that threatens triggering more severe and large wildfires because of human activities. [ABSTRACT FROM AUTHOR]

Traditional uses of the forest (timber, forage) have been giving way to other uses more in demand (recreation, ecosystem services). An observable consequence of this process of forest land use conversion is an increase in more difficult and extreme wildfires. Wildland forest management and protection program budgets are limited, and managers are requesting help in finding ways to objectively assign their limited protection resources based on the intrinsic environmental characteristics of a site and the site's interrelationship with available firefighting resources and existing infrastructure. A Fire Suppression Priority Index, integrating information on both the potential fire behaviour risk (Potential Fire Behaviour Index) and the fire suppression difficulty (Suppression Difficulty Index), provides managers with fundamental information for strategic planning and development of tactical operations to protect the natural environment. Results in the Córdoba Province, Andalusia's autonomous region, Spain, showed a statistically significant relationship between wildfire size and all three indices, demonstrating the utility of the methodology to identify and prioritise forest areas for strategic and tactical fire management operations. In addition, the methodology was tested and validated by trained and qualified wildfire management personnel in Chile and Israel, obtaining similar results as in Spain. [ABSTRACT FROM AUTHOR]

The spatial and temporal behavior of the occurrence of forest fires in Chile was evaluated in the presence of COVID-19 and mobility restrictions. The fire period from 2015-2016 to 2020-2021 was considered and statistics on mobility restrictions were granted by the Government of Chile. The analysis was developed at different scales of geographic perception. At the national and regional levels, the global behavior of the occurrence was determined, and later at the communal level, the political territorial unit, to determine internal variations attributable to the mobility dynamics in the quarantine period. In the process, the meteorological background of the fire activity was also considered. The results indicate that it is possible to rule out a meteorological effect, based on the variation of the moisture content of fine fuel. There was also no statistical association between the humidity of the fuel and the variation in the occurrence of fires. It is concluded that the communes that presented the greatest mobility of people before the pandemic were those that obtained the greatest reduction in fires. The variation in mobility, the product of restriction measures, is a statistical predictor of the increase or decrease in fires.

Fuel moisture content (FMC) proved to be one of the most relevant parameters for controlling fire behavior and risk, particularly at the wildland-urban interface (WUI). Data relating FMC to spectral indexes for different species are an important requirement identified by the wildfire safety community. In Valparaíso, the WUI is mainly composed of Eucalyptus Globulus and Pinus Radiata—commonly found in Mediterranean WUI areas—which represent the 97.51% of the forests plantation inventory. In this work we study the spectral signature of these species under different levels of FMC. In particular, we analyze the behavior of the spectral reflectance per each species at five dehydration stages, obtaining eighteen spectral indexes related to water content and, for Eucalyptus Globulus, the area of each leave—associated with the water content—is also computed. As the main outcome of this research, we provide a validated linear regression model associated with each spectral index and the fuel moisture content and moisture loss, per each species studied. [ABSTRACT FROM AUTHOR]