52 research outputs found

    Los anillos de crecimiento como indicadores climáticos

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    Short communication: Many missing rings in old Canary pines can be related with age, fires and traditional uses

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    Nuevas citas de olmo de montaña (Ulmus glabra Huds.) en el sector oriental del sistema central español

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    Se citan y describen trece nuevas poblaciones de Ulmus glabra Huds., en el sector oriental del sistema central español, en las provincias de Guadalajara, Madrid y Segovia. Palabras clave: corología, Ulmus, Sistema Central, España. ----------ABSTRACT---------- New sites of wych elm (Ulmus glabra Huds.) in the eastern sector of the Spanish Central System. Thirteen new populations of Ulmus glabra Huds. in the eastern sector of the Spanish Central System, in the provinces of Guadalajara, Madrid and Segovia, are cited and described. Keywords: chorology, Ulmus, Spanish Central range

    Evidencias dendrogeomorfológicas de inundaciones en la cuenca alta del río Noguera Pallaresa (Pirineos, España)

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    Las zonas montañosas son propensas a inundaciones torrenciales que se caracterizan por su capacidad de movilizar grandes volúmenes de sedimentos y otros materiales como troncos y otras piezas de madera de gran tamaño. En el caso de la cuenca alta del río Noguera Pallaresa (Pirineos de Lleida, España), las principales inundaciones destructivas están bien identificadas y descritos sus principales parámetros, pero aún falta el detalle espacial y temporal de éstos y otros eventos menos severos. Con el objetivo de ampliar la información sobre los efectos de estas inundaciones, este trabajo analiza y compara diferentes fuentes de datos, a partir de muestreos dendrogeomorfológicos realizados en dos afluentes del río Noguera Pallaresa: el río Flamisell (en el margen derecho) y el río Romadriu (en el margen izquierdo). La datación de los principales indicadores dendrogeomorfológicos en ambos afluentes, especialmente cicatrices y cambios bruscos de crecimiento, así como las fechas estimadas de establecimiento de los árboles, se han contrastado con datos de fuentes documentales, geomorfológicas, meteorológicas e hidrológicas. Se ha comprobado que, en estas pequeñas y medianas subcuencas, con precipitaciones muy heterogéneas a causa de la orografía, los datos instrumentales (a menudo muy escasos) pueden no reflejar adecuadamente la dinámica hidrológica. Por tanto, se constata que el análisis de las fuentes dendrogeomorfológicas y documentales es fundamental para caracterizar y evaluar la incidencia de estas inundaciones torrenciales en diferentes ámbitos territoriales

    Subfossil macroremains in the iberian central range: preliminary results from new sites

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    Análisis dendroecológico de maderas holocenas en un yacimiento de Castilla la Mancha (España)

    Flood Hazard Management in Public Mountain Recreation Areas vs. Ungauged Fluvial Basins. Case Study of the Caldera de Taburiente National Park, Canary Islands (Spain)

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    Las Angustias River is an ungauged stream in the Caldera de Taburiente National Park (Spain), where frequent intense flash-flood events occur. The aim of this research is to analyze the flood hazard at the Playa de Taburiente. Based on the limited information available (short time-series of daily precipitation), a statistical frequency analysis of 24 h rainfall was completed and the precipitation results were transformed into surface runoff. To determine if the model underestimates the flows that are generated in the basin, the dendro-geomorphological information available was used to calibrate results. The results of the HMS model were significantly lower. At this point, both the rainfall data and the rainfall-runoff model were re-analyzed to maximize the rainfall intensity values and the runoff generated (increasing the CN value for the basin). For the 1997 flood event, a 1250 m3·s−1 flood minimizes the RMSE for the disturbed tree sample; this flow value also clearly exceeds any peak flow derived from the rainfall-runoff analysis. It is only when rainfall intensity and surface runoff are maximized that the peak flows obtained approximate those associated with dendro-geomorphological data. The results highlight the difficulties of flood hazard management in ungauged torrential basins in mountain recreational areas (such as National Parks). Thus, in the absence of flow records, when considering the maximum rainfall intensity scenario may be a useful and effective tool for flood risk management

    Improving Flood Maps in Ungauged Fluvial Basins with Dendrogeomorphological Data. An Example from the Caldera de Taburiente National Park (Canary Islands, Spain)

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    Flash floods represent one of the more usual natural hazards in mountain basins, and, combined with the lack of reliable flow data and the recreational use of the drainage basin by tourists and hikers, there is a significant risk of catastrophe. Here, we present a dendro-geomorphological reconstruction of a past flash flood event in the Caldera de Taburiente N.P. (Canary Islands, Spain), an ungauged drainage basin in the SW side of the volcanic island of La Palma. We couple two-dimensional hydraulic modelling in a highly-resolved topographic environment (LiDAR data) with (1) peak flow data for various Tyear return periods from an uncalibrated hydrological model and (2) a data set of scars on trees, to investigate the magnitude of a 1997 dated flash-flood. From the results, flood hazards and associated risks would be clearly underestimated by using only the unique available hydrological data (a rainfall gauge station downstream of the study area). Hydraulic models using scars data show a higher flood hazard scenario, improving the flood hazard map by using all available flood evidence. Moreover, all this will allow for better implementation of appropriate adaptation policies by National Park managers, and therefore the mitigation of future disasters
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