En las últimas décadas, los incendios forestales han sido una preocupación en distintas regiones del mundo, especialmente, por el incremento en su ocurrencia producto de actividades humanas y cambios ...en el clima. En este estudio se examinaron las tendencias espacio-temporales en la ocurrencia y superficie afectada por incendios en la región del Maule durante el período 1986-2012. Se utilizó la base de datos de incendios de la Corporación Nacional Forestal, cuyos registros fueron representados espacialmente mediante una grilla de 2x2 km. La ocurrencia se mantuvo estable durante el periodo analizado con un promedio de 378 eventos por año. La superficie quemada presentó tres periodos por sobre el promedio de 5.273 hectáreas al año. La mayor parte de los incendios afectó superficies < 5 ha, mientras que un número muy pequeño de eventos explicaron la mayor parte del área quemada anualmente en la región. Según el combustible de inicio, aumentaron aquellos eventos iniciados en plantaciones forestales y disminuyeron aquellos originados en bosque nativo. Las causas de incendios asociadas al tránsito y al transporte resultaron ser las más importantes. El número de eventos causados accidentalmente por quema de desechos aumentó significativamente en el periodo estudiado. La mayor parte de los incendios se localiza en la zona costera y en el llano central, fuertemente asociados a la red vial y a las ciudades más pobladas. Este trabajo es una contribución a la caracterización de los incendios forestales en la región del Maule, representando las estadísticas de incendios de forma espacialmente explícita.
During the last decades, climate and land use changes led to an increased prevalence of megafires in Mediterranean-type climate regions (MCRs). Here, we argue that current wildfire management ...policies in MCRs are destined to fail. Focused on fire suppression, these policies largely ignore ongoing climate warming and landscape-scale buildup of fuels. The result is a 'firefighting trap' that contributes to ongoing fuel accumulation precluding suppression under extreme fire weather, and resulting in more severe and larger fires. We believe that a 'business as usual' approach to wildfire in MCRs will not solve the fire problem, and recommend that policy and expenditures be rebalanced between suppression and mitigation of the negative impacts of fire. This requires a paradigm shift: policy effectiveness should not be primarily measured as a function of area burned (as it usually is), but rather as a function of avoided socio-ecological damage and loss.
In recent decades large fires have affected communities throughout central and southern Chile with great social and ecological consequences. Despite this high fire activity, the controls and drivers ...and the spatiotemporal pattern of fires are not well understood. To identify the large-scale trends and drivers of recent fire activity across six regions in south-central Chile (~32-40° S Latitude) we evaluated MODIS satellite-derived fire detections and compared this data with Chilean Forest Service records for the period 2001-2017. MODIS burned area estimates provide a spatially and temporally comprehensive record of fire activity across an important bioclimatic transition zone between dry Mediterranean shrublands/sclerophyllous forests and wetter deciduous-broadleaf evergreen forests. Results suggest fire activity was highly variable in any given year, with no statistically significant trend in the number of fires or mean annual area burned. Evaluation of the variables associated with spatiotemporal patterns of fire for the 2001-2017 period indicate vegetation type, biophysical conditions (e.g., elevation, slope), mean annual and seasonal climatic conditions (e.g., precipitation) and mean population density have the greatest influence on the probability of fire occurrence and burned area for any given year. Both the number of fires and annual area burned were greatest in warmer, biomass-rich lowland Bío-Bío and Araucanía regions. Resource selection analyses indicate fire 'preferentially' occurs in exotic plantation forests, mixed native-exotic forests, native sclerophyll forests, pasture lands and matorral, vegetation types that all provide abundant, flammable and connected biomass for burning. Structurally and compositionally homogenous exotic plantation forests may promote fire spread greater than native deciduous-Nothofagaceae forests which were once widespread in the southern parts of the study area. In the future, the coincidence of warmer and drier conditions in landscapes dominated by flammable and fuel-rich forest plantations and mixed native-exotic and sclerophyll forests are likely to further promote large fires in south-central Chile.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
RESUMEN El bosque de Araucaria araucana (“pewén” en lengua Mapuche), con sus especies asociadas del género Nothofagus, es singular desde el punto de vista evolutivo, biológico y sociocultural. Por la ...interdependencia con el pueblo Mapuche-Pewenche, se lo considera un ecosistema biocultural. Este trabajo es una revisión integral binacional de información científica actualizada aplicable a su gestión y conservación. La comunidad científica avanzó significativamente en el conocimiento de: a) la interrelación y significancia del ecosistema biocultural; b) la diversidad genética regional; c) el régimen de incendios, sus factores determinantes, su rol en el bosque y la capacidad de recuperación de la biodiversidad frente a distintas severidades de quema; d) el rol ecológico de la producción de semillas y sus interacciones con la fauna granívora y nidificadora de cavidades; e) el decaimiento y muerte del dosel debido al estrés ambiental y al surgimiento de nuevos patógenos del pewén; f) las consecuencias de la invasión de pinos y de mamíferos exóticos que alteran las interacciones biológicas y los procesos ecológicos originales y; g) los efectos de la ganadería y la sobreexplotación de leña y piñones sobre la integridad ecológica y la biodiversidad. Este conocimiento se considera fundamental para fortalecer políticas y estrategias de protección, conservación y gestión de este ecosistema endémico, escaso, amenazado regional y globalmente declarado en peligro. Frente a las problemáticas identificadas, es imperioso lograr el empoderamiento social del pueblo Mapuche-Pehuenche, el respeto intercultural y la efectivización de las políticas públicas para la conservación y uso sustentable de este ecosistema biocultural.
Abstract
This paper evaluates the relationship between fire occurrence (number and burned area) and climate variability (precipitation and maximum temperatures) across central and south‐central Chile ...(32°–43° S) during recent decades (1976–2013). This region sustains the largest proportion of the Chilean population, contains ecologically important remnants of endemic ecosystems, the largest extension of forest exotic plantations, and concentrates most of the fire activity in the country. Fire activity in central Chile was mainly associated with above‐average precipitation during winter of the previous year and with dry conditions during spring to summer. The later association was particularly strong in the southern, wetter part of the study region. Maximum temperature had a positive significant relationship with burned area across the study region, with stronger correlations toward the south. Fires in central Chile were significantly related to El Niño–Southern Oscillation, through rainfall anomalies during the year previous to the fire season. The Antarctic Oscillation during winter through summer was positively related to fires across the study area due to drier/warmer conditions associated with the positive polarity of this oscillation. Climate change projections for the region reveal an all‐season decrease in precipitation and increases in temperature, that may likely result in an increment of the occurrence and the area affected by fires, as it has been observed during a multi‐year drought afflicting central Chile since 2010.
En muchas regiones del mundo los incendios están siendo cada vez más frecuentes y severos. Las principales causas de estos patrones se asociarían tanto a cambios en el clima como en las prácticas de ...uso de la tierra. La presente contribución examina sucintamente los recientes cambios y proyecciones climáticas y su potencial influencia en la ocurrencia de incendios en la zona centro-sur de Chile, así como las medidas de adaptación necesarias para hacer frente a este problema. Diversos estudios coinciden en que el mayor efecto del cambio climático en esta zona estará asociado a la disminución de las precipitaciones lo cual incidiría en un incremento de la ocurrencia y área afectada por incendios forestales. Bajo este escenario, el principal desafío está en definir acertadamente las políticas y estrategias de mitigación y adaptación sectoriales con la finalidad de promover bosques más saludables, -en términos de productividad, diversidad y resiliencia- asegurando una provisión continua de servicios ecosistémicos bajo un clima cambiante.
Sustained human pressures on the environment have significantly increased the frequency, extent, and severity of wildfires, globally. This is particularly the case in Mediterranean regions, in which ...human-caused wildfires represent up to 90% of all recorded wildfire ignitions. In Chile, it has been estimated that nearly 90% of wildfires are related to human activities, and that their frequency and distribution have steadily increased over the last decade. Despite this, the role of socio-economic factors in driving wildfire activity and its spatiotemporal distribution remains unclear. In this study, we assess the association between socio-economic drivers and spatiotemporal patterns of wildfires in the Mediterranean region of south-central Chile over the period 2010–2018. Our results show that 98.5% of wildfires are related to human activities, either accidentally (58.2%) or intentionally (36.6%). Wildfires occurred primarily during the summer months and their density at the commune-level was associated with increased road access, as well as with the percentage of land covered by agriculture, exotic tree plantations, and native forest. Wildfire activity at the commune-level was also related to socio-economic variables such as population density, proportion of indigenous population, and unemployment rate, although such associations varied considerably depending on the region and on whether the wildfire was started accidentally or intentionally. Our study provides a comprehensive and interdisciplinary assessment of the complex ways in which land-cover and socio-economic factors drive the distribution of wildfire activity in south-central Chile. It represents an important guide for policy-making, as well a baseline for research into strategies aimed at predicting and mitigating wildfire activity at both local and national levels.
Display omitted
•In south-central Chile 98.5% of fire ignitions are caused by people.•Fires occur primarily during the summer months.•Fire density is associated with road access and landcover type.•Population density and unemployment rate were important socio-economic drivers.•Fire management needs to consider social, ecological and economic dimensions.
Forest fire activity has increased in recent years in central and south‐central Chile. Drought conditions have been associated with the increase of large wildfires, area burned and longer fire ...seasons. This study examines the influence of drought on fire regimes and discusses landscape management opportunities to decrease fire hazard. Specifically, we investigate the effect of the 2010–2015 Megadrought (MD) compared to 1990–2009 period on fire activity (fire‐season length, number of fires and burned area across months, fire sizes, regions and vegetation cover types, simultaneity, and duration of fires) in central and south‐central Chile (32°–39° S), using contemporary fire statistics derived from the Chilean Forest Service. For large fire events (>200 ha) the average season length increased by 67 d (44%), comparing 2010–2015 to 1990–2009. Earlier and later ignition dates resulted in extended fire seasons in MD years. During the MD, the number, area burned, simultaneity, and duration of large fires increased significantly compared to the control period, including the unprecedented occurrence of large fires during winter. The burned area in large fires increased in all vegetation types, during the MD compared to the control period, especially in the exotic plantation cover type. The regions that were most affected by fire (i.e., total area burned) during the MD were Maule, Bío‐Bío, and Araucanía (35–39° S) that concentrate >75% of forest plantations in Chile. Although both maximum temperatures and precipitation are drivers of fire activity, a simple attribution analysis indicates that the sustained rainfall deficit during 2010–2015 was the most critical factor in the enhanced fire activity. Future climate change predictions indicate more recurrent, intense, and temporally extended droughts for central and south‐central Chile. Under this scenario, land‐use planning and fire and forest management strategies must promote a more diverse and less flammable landscape mosaic limiting high load, homogenous, and continuous exotic plantations.
► Plantations grew ten-fold in 32 years at 6375hayear−1 (6.4% annual rate). ► A large percentage of plantations (32%) occurred on large corporate landholdings. ► A large percentage of new plantations ...directly caused deforestation. ► The autologistic model can help predict areas most vulnerable to future change.
Timber plantation expansion is a significant form of landscape change with reported negative environmental and social impacts. We analyze the proximate drivers of plantation expansion in southcentral Chile, one of the countries in South America with the highest rates of afforestation and reforestation in the last decades. Satellite images from 1975, 1990 and 2007 were used to estimate autologistic regressions for the periods 1975–1990 and 1990–2007. Timber plantations (mostly Pinus radiata) increased from 29,213ha in 1975 (5.5% of the landscape) to 224,716ha in 2007 (42.4% of the landscape). We found a clearer pattern of expansion between 1975 and 1990 as compared to 1990–2007, associated with soils of forest suitability, steep slopes, and proximity to main cities, corporate landholding, and large farms. Between 1990 and 2007 some of these drivers lost significance as plantations expanded in all directions and became the predominant land cover. Additionally, 41.5% of new plantations in the 1975–1990 period and 22.8% in the 1990–2007 period were established by clearing secondary native forests, which corroborates that plantation expansion in Chile has been a direct cause of deforestation and biodiversity loss. Understanding the proximate drivers of plantation expansion is essential in order to advance our comprehension of the underlying patterns and causes of this landscape change, which will allow us to better predict which areas are more vulnerable to change, and help to prevent adverse environmental and social impacts as plantations expand to the southern regions of the country.
Chile's Valparaíso hills on fire González, Mauro E; Syphard, Alexandra D; Fischer, A Paige ...
Science (American Association for the Advancement of Science),
2024-Mar-29, 2024-03-29, 20240329, Letnik:
383, Številka:
6690
Journal Article
PDF
