Papers by Cristina Vega-Garcia
Science of The Total Environment, Apr 1, 2021
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
EGU General Assembly Conference Abstracts, Apr 1, 2019
Cuadernos de la Sociedad Española de Ciencias Forestales, Dec 21, 2017
Aunque la ordenación de montes ha sido necesariamente multifuncional en nuestras condiciones medi... more Aunque la ordenación de montes ha sido necesariamente multifuncional en nuestras condiciones mediterráneas, nunca ha experimentado más y más diversas demandas que en la actualidad, y es de esperar que éstas aumenten en intensidad en un futuro previsible en el que el desafío radicará en cómo conseguir el aumento de la productividad forestal sin perjuicios para otras funciones. Los avances experimentados por tecnologías de adquisición y análisis de datos (Big Data) medioambientales y forestales a alta resolución espacial y temporal (teledetección, LIDAR), prácticamente a la carta, suministran un nivel de conocimiento y análisis de los sistemas forestales que permite optimizar la toma de decisiones, la modelización y la simulación de sus dinámicas en el futuro, y a su vez anticipar la provisión de los numerosos servicios ecosistémicos demandados. Esta ponencia repasa dichos avances tecnológicos, al tiempo que establece su relación con condicionantes estructurales que han lastrado la planificación forestal desde sus inicios en el país: la estructura de la propiedad, y las políticas forestales.
Imprensa da Universidade de Coimbra eBooks, 2022
In the European Mediterranean region natural-caused wildfires are a small fraction of total ignit... more In the European Mediterranean region natural-caused wildfires are a small fraction of total ignitions. Lightning strikes are the most common source of non-human fires, being strongly tied to specific synoptic conditions and patterns associated with atmospheric instability, such as dry thunderstorms. Likewise, lightning-related ignitions often associate with dry fuels and dense vegetation layers. In the case of Iberian Peninsula, the confluence of these factors favors recurrent lightning fires in the eastern Mediterranean mountain ranges, the western region of "El Bierzo" and central Portugal. However, under appropriate conditions lightning fires can start elsewhere, holding the potential to propagate over vast distances. In this work, we assessed the likelihood of ignition leveraging a large dataset of lightning strikes and historical fires available in Spain. We trained and tested a machine learning model to evaluate the probability of ignition provided that a lightning strikes the ground. Our model was calibrated in the period 2009-2015 using data for mainland Spain plus the Balearic Islands. To build the binary response variable we classified lightning strikes between that triggered a fire event. For each lightning strike we extracted a set of covariates relating fuel moisture conditions, the presence and density of the vegetation layer and the shape of the relief. The final model was subsequently applied to forecast daily probabilities at 1x1 km resolution for the entire Iberian Peninsula. Although the model was originally calibrated in Spain, we extended the predictions to the entire Iberian Peninsula. By doing so we were able to validate in the future our outputs against the Portuguese dataset of recent naturalcaused fires (bigger than 1 ha) from 2001 to 2021. Overall, the model attained a great predictive performance with a median AUC of 0.82. Natural-caused ignitions triggered mainly in low dead (dFMC <8%) and moderate alive (DC > 250) fuel moisture conditions. Lightning strikes with negative polarity seem to trigger fires more frequently when the mean density of discharger was greater than 5. Finally, natural wildfires usually started at higher elevations (above 500 m.a.s.l.).
Science of The Total Environment, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Landscape and Urban Planning, Oct 1, 2022
Science of The Total Environment, Apr 1, 2021
Wildfires in the Mediterranean are strongly tied to human activities. Given their particular link... more Wildfires in the Mediterranean are strongly tied to human activities. Given their particular link with humans, which act as both initiators and suppressors, wildfire hazard is highly sensitive to socioeconomic changes and patterns. Many researchers have prompted the perils of sustaining the current management policy, the so-called ‘total fire exclusion’. This policy, coupled to increasingly fire-prone weather conditions, may lead to more hazardous fires in the mid-long run. Under this framework, the irruption of the COVID-19 pandemic adds to the ongoing situation. Facing the lack of an effective treatment, the only alternative was the implementation of strict lockdown strategies. The virtual halt of the system undoubtedly affected economic and social behavior, triggering cascading effects such as the drop in winter-spring wildfire activity. In this work, we discuss the main impacts, challenges and consequences that wildfire science may experience due to the pandemic situation, and identify potential opportunities for wildfire management. We investigate the recent evolution of burned area (retrieved from the MCD64A1 v006 MODIS product) in the EU Mediterranean region (Portugal, Spain, France, Italy and Greece) to ascertain to what extent the 2020 winter-spring season was impacted by the public health response to COVID-19 (curfews and lockdowns). We accounted for weather conditions (characterized using the 6-month Standardized Precipitation Evapotranspiration Index; SPEI6) to disregard possible weather effects mediating fire activity. Our results suggest that, under similar drought-related circumstances (SPEI6 ≈ -0.7), the expected burned area in 2020 during the lockdown period in the EU (March-May) would lay somewhere within the range of 38,800 ha ± 18,379 ha. Instead, the affected area stands one order of magnitude below average (3,325 ha). This stresses the need of considering the social dimension in the analysis of current and future wildfire impacts in the Mediterranean region.
Journal of Environmental Management, May 1, 2012
The pastoral use of fire to regenerate rangelands is a major cause of wildfires in many Mediterra... more The pastoral use of fire to regenerate rangelands is a major cause of wildfires in many Mediterranean countries. Despite producing important environmental impacts, this phenomenon has hardly ever been studied separately from other wildfire ignition causes. As extensive livestock breeding relies on the available pasture resources, we hypothesised that a higher rate of pastoral wildfire ignitions could be associated with land cover patterns, as these reflect the spatial arrangement of human activities in managed landscapes. To investigate these patterns, we studied landscape structure and the pastoral wildfires recorded between 1988 and 2000 in 24 Nature Park landscapes in Andalusia (Spain). The CORINE Land Cover map was reclassified according to five levels of grazing use and landscape metrics were calculated. Neural networks were developed to model the relationship between landscape metrics and pastoral wildfires, obtaining a set of significant variables which are discussed in the frame of land and livestock management in the region. We conclude that pastoral wildfire ignitions are more likely in landscapes where the pattern of being dominated by a matrix composed of several large patches of low to moderate grazing use, and having abundant small and elongated patches of higher grazing use, is more extreme. This pattern could be reflecting the persistence of numerous small livestock farms within an increasingly abandoned agrarian landscape. To prevent pastoral wildfires, land management could attempt to enlarge and merge those small patches of higher grazing use, reducing the amount of interface and their intermixture with the surrounding poorer pasture resources.
spatial statistics, Mar 1, 2019
In this study, we analyzed the recent dynamics of forest fires in Quercus suber stands in Sardini... more In this study, we analyzed the recent dynamics of forest fires in Quercus suber stands in Sardinia (Italy), Corsica (France), and Catalonia (Spain) for the period 2003-2015.
European Journal of Forest Research, 2020
Understory cover may constraint tree regeneration, impair livestock grazing and increase wildfire... more Understory cover may constraint tree regeneration, impair livestock grazing and increase wildfire hazard. While prescribed burning and thinning are potential options for managing understory, resprouting vigor of large shrubs and small trees negatively affects their cost-benefit ratio. Selection of the largest stem and cleaning the rest of the stools can be an alternative option, if the stem left competes with resprouts for belowground resources. Alternatively, resources stored in the reserved stem may promote the growth of resprouts. Although few studies documented the effects of stem selection on resprouting vigor, no information is available for understory species. This study assessed the effect of stem selection (SS) in comparison to cleaning (CC) on resprouting vigor of box-tree. Both options were randomly applied to individuals growing in the understory of black pine forest in four localities. The resprout number resprouts (Rn) and the maximum resprout length (Lmax) were modeled against treatment, stand canopy cover, and pre-treatment stool basal area. Light availability at the individual level was assessed in a subset (n = 38) growing in two localities. Rn and Lmax were lower in SS than in CC. SS apparently inhibited bud initiation and prompted the reserved stem to compete for belowground resources with new resprouts. Resprouting was negatively related to the stand canopy cover. This effect of light availability was corroborated when measured at the individual level. As a conclusion, the implementation of SS in sub-Mediterranean forests with understory dominated by box-tree is a better management alternative than CC for fuel and forest management purposes.
Desde los años 70 se han creado en nuestros montes áreas recreativas basadas en un modelo de conc... more Desde los años 70 se han creado en nuestros montes áreas recreativas basadas en un modelo de concentración de visitantes y de infraestructuras en cuarteles de recreo. El destino de estas áreas ha sido muy desigual, planteando problemas de gestión al no contarse generalmente con datos fiables de campo sobre afluencia de visitantes y sus características. Este artículo propone como solución la observación directa sobre las áreas recreativas existentes y la recogida de unas pocas variables de interés adaptadas de forma local. Se muestran los resultados más relevantes de la aplicación de este método en seis áreas recreativas en montes públicos de la comarca del Valle de Arán (Lérida). A pesar de su simplicidad, este método proporciona suficiente información para la toma de decisiones sobre el destino de las infraestructuras del área recreativa, y un diagnóstico de los problemas que puedan afectar al entorno físico-biológico y social de los usuarios, lo que permite aplicar las medidas de gestión oportunas.
Landscape Ecology, 2006
... Cristina Vega-Garcı´a1,* and Emilio Chuvieco2 1Agriculture and Forest Engineering Department,... more ... Cristina Vega-Garcı´a1,* and Emilio Chuvieco2 1Agriculture and Forest Engineering Department, University of Lleida, Avda. ... Burned areas in the period showed lower patch density, lower Shannon diversity in-dex, and higher mean patch size before wildfire than non-burned ...
Journal of Environmental Management, 2012
The pastoral use of fire to regenerate rangelands is a major cause of wildfires in many Mediterra... more The pastoral use of fire to regenerate rangelands is a major cause of wildfires in many Mediterranean countries. Despite producing important environmental impacts, this phenomenon has hardly ever been studied separately from other wildfire ignition causes. As extensive livestock breeding relies on the available pasture resources, we hypothesised that a higher rate of pastoral wildfire ignitions could be associated with land cover patterns, as these reflect the spatial arrangement of human activities in managed landscapes. To investigate these patterns, we studied landscape structure and the pastoral wildfires recorded between 1988 and 2000 in 24 Nature Park landscapes in Andalusia (Spain). The CORINE Land Cover map was reclassified according to five levels of grazing use and landscape metrics were calculated. Neural networks were developed to model the relationship between landscape metrics and pastoral wildfires, obtaining a set of significant variables which are discussed in the frame of land and livestock management in the region. We conclude that pastoral wildfire ignitions are more likely in landscapes where the pattern of being dominated by a matrix composed of several large patches of low to moderate grazing use, and having abundant small and elongated patches of higher grazing use, is more extreme. This pattern could be reflecting the persistence of numerous small livestock farms within an increasingly abandoned agrarian landscape. To prevent pastoral wildfires, land management could attempt to enlarge and merge those small patches of higher grazing use, reducing the amount of interface and their intermixture with the surrounding poorer pasture resources.
International Journal of Wildland Fire, 2012
The main goal of this study was to explain the relationship between forest fires and different cl... more The main goal of this study was to explain the relationship between forest fires and different climatic, topographic and vegetation factors, establishing explanatory models from multivariate analysis. The study area comprised peninsular Spain. Two dependent variables were considered: probability of burning and fire size class, from a forest-fire map derived from visual analysis of satellite images from 1991 to 2005 (3337 fires greater than 25 ha). Logistic regression, discriminant analysis and regression trees were used to analyse the probability of burning. The models showed a significant relationship with land cover and slope, where the classification achieved an agreement of ~66%, and this was very similar for the three statistical methods used. Discriminant analysis and regression trees were used to model fire size class. These models appeared more related to ecozones and climatic variables (winter precipitation and mean summer temperature). In this case, the best classification...
A review of remote sensing methods …, 1997
... 1989, Application of remote sensing and Geographic Information Systems to forest fire hazard ... more ... 1989, Application of remote sensing and Geographic Information Systems to forest fire hazard mapping. ... SALAS, J., 1996, Mapping the spatial distribution of forest fire danger using GIS, Int. ... J., 1981, Scene analysis for wildland fire-fuel characteristics in a Mediterranean climate. ...
gis.fs.fed.us
Abstract: A study was conducted in 2002 with the aim of defining and analysing, both spatially an... more Abstract: A study was conducted in 2002 with the aim of defining and analysing, both spatially and temporally, meteorological, topographic, socio-demographic and vegetation conditions which might be linked to the occurrence of forest fires caused by humans in Catalonia in Spain, ...
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Papers by Cristina Vega-Garcia