Modeling tree-growth: Assessing climate suitability of temperate forests growing in Moncayo Natural Park (Spain)

In the past few decades, temperate forests have been negatively altered by numerous anthropogenic activities and by the impact of ongoing climate change. These changes may require management actions to help preserve some forest tree species. In this sense, highly-detailed knowledge of tree growth and survival across territorial and climatic gradients will be important for forest conservation. We developed a novel approach to determine the optimal zones of forest growth and expansion through climate suitability maps, using a dense tree-ring network of four forest species in Moncayo Natural Park and high-resolution climate data. Our results showed that the mixed-effects models developed using climate data and tree size were able to predict between 65 and 80% of growth variability along the climatic gradient. All studied species were influenced by climate, and the relationship between growth and climate significantly differed along the prevailing climate gradient. Moreover, the suitability maps showed that the current species distribution is limited, and their application may serve as a tool for adaptive management in forests subjected to climate change

Dynamic changes in the lower Gállego River (Ebro Basin, NE Spain) and their relationship with anthropic activities and the quaternary substrate

The lower Gállego River has been strongly degraded since the 1960s due to human activity (gravel mining, dump accumulation, channeling works), which has produced a deep channel incision. Although these humandriven processes are usually reported in fluvial bibliography, in this case, more complex results are observable. For instance, regarding the depth and incision rates, we observed no relationship between the most anthropically impacted areas and the sections with the deepest incisions; moreover, the deepening process continues 40 years after the human interventions ceased. The reason for this maladjustment is the role played by the exhumation of the underlying Pleistocene substrate, affected by the synsedimentary processes of karstification. The appearance of paleodolines filled with fine sediments on the incision bottom and sides is the main factor conditioning the continuity and magnitude of the process. Besides, these paleodepressions direct the river dynamics and course, thus favoring its widening when they appear and causing the development of a new riverbed (Qt13) while the 1960s floodplain (Qt12) is becoming an old terrace located between 5 and 11 m above the new alluvial bottom. There are no previous records about this kind of consequences in the regional fluvial dynamics. El curso bajo del río Gállego ha sido fuertemente degradado desde los años 1960 por la actividad antrópica (extracción de áridos, acumulaciones de escombros, obras de encauzamiento) que ha conducido a una fuerte incisión. Aunque este tipo de procesos inducidos por el hombre son habituales en la bibliografía fluvial, en este caso se aprecian efectos más complejos. Son, por ejemplo, la profundidad y velocidad de la incisión, la falta de relación entre puntos de máxima intervención y los de mayor incisión o la continuidad del proceso cuarenta años después de cesar ese tipo de acciones. La respuesta a estos desajustes está en el papel que está jugando la exhumación del sustrato pleistoceno infrayacente, afectado por procesos sinsedimentarios de karstificación. La aparición de paleodolinas rellenas de sedimentos finos en el fondo y laterales de la incisión es actualmente el principal determinante de su importancia y continuidad. Además, estas paleodepresiones dirigen la dinámica y trazado del río y puntualmente favorecen ensanchamientos laterales. Esto propicia la aparición de un nuevo lecho (Qt13) a medida que el lecho de los años 1960 (Qt12) va quedando como una terraza colgada entre 5 y 11 m sobre el nuevo fondo aluvial. No hay antecedentes de este tipo de consecuencias en la dinámica fluvial regional

Tendencias estacionales de la precipitación en la cuenca del Ebro 1951-2000

We have analyzed seasonal and annual precipitation trend in the Ebro catchment (NE Spain) during the second half of XXth (1951 2000). Data analyzed come from monthly precipitation data base of Mediterranean Spain (MOPREDAMES). The total amount of rainfall series is 424 and the mean value of spatial density is 1 observatory per 200 km2; data base include information in altitude until 1250 m osI. The results allow us to suggest that in the Ebro catchment during the second half of the XXth century annual precipitation has slight decreased in 3/4 of total stations. At seasonal scale the most generalized decreasing of precipitation is found during summer (44% of total stations). Significant decreasing affects 1/3 of total stations in winter, spring and fall. Spatial differences can be described. In winter precipitation shows a generalized negative trend but mainly not significant. During spring and summer we have detected slight increment in the upper catchment area, while left margin of the Ebro catchment has been under negative and significant trend. A clear difference exits from N to S during autumn, with positive and negative trend respectively.Hemos analizado las tendencias de la precipitación anual y estacional de la cuenca del Ebro durante la segunda mitad del siglo XX (1951-2000) con todos los observatorios procedentes de la base de datos de precipitaciones mensuales de la vertiente mediterránea española (MOPREDAMES). El total de series analizadas es de 424, lo que supone una densidad promedio de 1 observatoriocada 200 km2, incluyendo información hasta 1250 m de altitud. Los resultados permiten sugerir que existe un ligero y generalizado descenso de los totales anuales de precipitación que afecta a 3/4 del total de observatorios. Estacionalmente el verano es la estación que muestra un descenso significativo más generalizado (44% de observatorios). En invierno, primavera y otoño el descenso afecta a 1/3 del total. Sin embargo en el espacio el comportamiento de cada estación difiere. Durante el invierno el descenso es generalizado (aunqueno significativo), en primavera y verano se detectan ligeros incrementos de precipitación en la cabecera de la cuenca, mientras en la margen izquierda se localiza un área donde predominan las pérdidas con carácter significativo. El otoño permite establecer una clara distinción entre la margen izquierda, con tendencia positiva, y la margen derecha, con tendencia negativa

Dendro-anthracological tools applied to Scots type pine forests exploitation as fuel during the Mesolithic-Neolithic transition in the southern central pre-Pyrenees (Spain)

This work focuses on the reconstruction of fuelwood procurement during the Mesolithic-Neolithic transition in the southern central Pre-Pyrenees (Spain). The study combines wood charcoal identification with the application of dendro-anthracological approaches in the archaeological sequence of Esplugón (9.4–6.8 kyr cal BP) (Sabiñanigo, Huesca). Scots type pine (Pinus sylvestris tp.) reaches in this record around 90% of exploited firewood in line with its abundance in the inner Iberia mountainous areas during the onset of the Holocene. The classification of pine wood fragments in anthraco-groups is based on the combination of different dendro-anthracological tools: i) pith location tool and wood diameter estimation based on the trigonomethric method tool (ADmodel), ii) the study of growth rate based on the annual tree-ring width measurements, and iii) a modern dendrological dataset. There are hardly any differences observed in firewood procurement between the last hunter-gatherers and the first farmers in the long sequences from rock-shelters with recurrent human occupations. First results from this site point to the exploitation of whole trees but a high use of small pine branches probably from the gathering of branch shedding

Cartografía histórica y reconstrucción paleotopográfica y geoarqueológica de la ciudad romana de caesar augusta (Zaragoza, España)

En este trabajo se ofrece una aproximación a la reconstrucción de la topografía y las características del terreno de Caesar Augusta (Zaragoza). Esta reconstrucción ha sido modelada integrando en un Sistema de Información Geográfico (SIG) el mapa topográfico de Casañal de 1880 –anterior a las principales transformaciones urbanas ocurridas en la ciudad- e información geomorfológica, geoarqueológica y arqueológica. Caesar Augusta fue fundada por los romanos junto al río Ebro en el siglo I aC sobre un asentamiento ibérico previo (Salduie). El área urbana ocupaba una terraza fluvial cuaternaria en la confluencia de los ríos Ebro y Huerva. Esta terraza se eleva unos 10 m sobre esos ríos, con altitudes que varían entre 200-208 m s.n.m. La topografía actual de la ciudad ha variado sustancialmente a lo largo del tiempo, de modo que no es apropiada para reconstruir la morfología original del terreno donde los romanos fundaron Caesar Augusta . Se ha utilizado ArcGIS 10.0 y sus módulos ArcMap y ArcScene para la gestión y análisis de los datos. Los modelos 3D generados muestran muchos elementos topográficos de detalle que en mapas anteriores pasaban desapercibidos. Estos modelos son complementados con datos de la naturaleza geológica del subsuelo provenientes de observaciones realizadas en diversas excavaciones arqueológicas. El modelo digital del terreno derivado del mapa de Casañal y las informaciones complementarias sólo son válidas para reconstrucciones generales. Sin embargo, ha mejorado nuestro conocimiento sobre muchos elementos romanos de Caesar Augusta (topografía del Decumanus y Cardo maximus , cloacas, fosos, muralla, teatro y foro). Y, es más, es ahora posible comprender mejor la geomorfología y el dinamismo fluvial de la ciudad de Zaragoza. In this paper we provide a reconstruction of the topography and characteristics of the terrain of Caesar Augusta (the Roman name of the present-day city of Zaragoza). This reconstruction has been modelled using GIS and integrating the topographic map drawn by Casañal in 1880 –previous to the main urban transforma-tions-with geomorphological, geoarchaeological and archaeological data. Caesar Augusta was founded by Romans near the Ebro River in the 1st century BC in the same place where there was a previous Iberian settlement (Salduie). The urban area occupied a quaternary fluvial terrace in the confluence of the rivers Ebro and Huerva. The terrace stands about 10 m above these rivers, with a varying height between 208-200 masl. The present-day urban topography has suffered many transformations throughout history; therefore, it is impossible to reconstruct the original morphology of the land where the Romans decided to build their town in the past. We have used ArcGIS Desktop 10.0 and its platforms ArcMap and ArcScene for managing and analysing the data. 3D models show many fine topographic features that in were overlooked previous maps. These models are complemented with information about the underground geologic nature, which is known through the observations made in several archaeological excavations. The model derived from Casañal s map and complementary data is only valid for general reconstructions, but it has enhanced our knowledge of many elements of Caesar Augusta (topography of the Decumanus and Cardo maximus, sewage system, moats, wall, theatre, forum), making it possible to better understand the geomorphology and fluvial evolution of the city of Zaragoza

Holocene alluvial sequence in the val de zaragoza (Los Monegros) in the palaeoenvironmental context of the ebro basin (Ne Spain)

Flat-bottomed valleys formed by Holocene fills are the most characteristic landforms in the center of the Ebro basin. This paper analyzes, within a regional framework, a small fluvial basin located in the north of the Alcubierre Range. Three Holocene morphosedimentary units (H1-H3) and a sub-functional level (H4) are identified. These units are representative of the regional geomorphological evolutionary process in the Ebro basin. New chronological insights on climate and landscape management are provided by a study of the Bastarás weir, a construction made for water flow management during the Little Ice Age (LIA). The integration of Val de Zaragoza radiocarbon datings into the regional framework enables the authors to identify the main formation stages, as well as the influence of climatic and human factors on its evolution. The intensification of human pressure in the territory is reflected in a progressive increase in sediment accumulation rates in the valleys, peaking during Roman times and the Little Ice Age. Los valles de fondo plano formados por rellenos holocenos constituyen los paisajes más característicos del sector central de la cuenca del Ebro. En este trabajo se analiza una pequeña cuenca fluvial localizada en el norte de la Sierra de Alcubierre, en la que se han identificado tres unidades morfosedimentarias holocenas (H1-H3) y un nivel subfuncional (H4), que son representativos de la evolución geomorfológica regional de la Cuenca del Ebro. Uno de los aspectos más relevantes del valle lo constituye el azud de Bastarás, construcción realizada durante la Pequeña Edad del Hielo para el aprovechamiento del agua, que aporta nuevos datos cronológicos sobre dicha época y acerca de la gestión del territorio. La integración de las dataciones radiocarbónicas obtenidas en la Val de Zaragoza en un marco regional ha permitido precisar las principales etapas de formación de los valles de fondo plano, así como la importancia de los factores climáticos y humanos en su evolución. La intensificación de la presión humana sobre el territorio queda reflejada en un progresivo aumento en las tasas de acumulación de sedimentos en los valles, alcanzando sus picos máximos en Época Romana y en la Pequeña Edad del Hielo

Spatio‐temporal variability of daily precipitation concentration in Spain based on a high‐resolution gridded data set

An analysis of the spatial and temporal variability of daily precipitation concentration (CI) in Spain was made based on a high‐resolution (5 × 5 km) daily gridded precipitation data set for the 1950–2012 period. For each grid point in the Iberian Peninsula (IP) and Balearic and Canary Islands, the average annual CI was computed, as well as its coefficient of variation and the 5th and 95th percentiles. Annual values were also computed, and the time series of the index were used to assess temporal trends over the whole period. The spatial distribution of the CI showed a strong relationship with the orographic barriers near the coastlines. The Canary Islands showed the highest values of CI, along with the eastern Mediterranean facade of the IP. The highest inter‐annual variations of the CI occurred in the southern IP and in the southern Canary Islands. The trends of CI were, overall, positive and significant, which indicates an increase of daily precipitation concentration over the study period and an increasing environmental risks scenario where erosivity, torrentiality, and floods may become more frequent.This study was supported by research projects CGL2015-69985-R and CGL2014-52135 C3-1-R, and financed by the Spanish Ministerio de Economía y Competitividad (MINECO) and EU FEDER-ERDF funds. RSN, MDL, MAS, and LAL were supported by the Government of Aragón through the ‘Programme of research groups’ (group H38, ‘Clima, Agua, Cambio Global y Sistemas Naturales’), as well as SB (group ‘E68, Geomorfología y Cambio Global’). The authors would also like to thank the Climatology Group (2014SGR300, Catalan Government), the Convenio de Desempeño UTA-MINEDUC, and the FONDECYT Project 11160059 of the Chilean Government.Peer Reviewe