Declining pine growth in Central Spain coincides with increasing diurnal temperature range since the 1970s

Growing evidence suggests environmental change to be most severe across the semi-arid subtropics, with past, present and projected drying of the Mediterranean Basin posing a key multidisciplinary challenge. Consideration of a single climatic factor, however, often fails to explain spatiotemporal growth dynamics of drought-prone ecosystems. Here, we present annually resolved and absolutely dated ring width measurements of 871 Scots pines (Pinus sylvestris) from 18 individual plot sites in the Central Spanish Pinar Grande forest reserve. Although comprising tree ages from 6 to 175 years, this network correlates surprisingly well with the inverse May–July diurnal temperature range (r = 0.84; p < 0.00011956–2011). Ring width extremes were triggered by pressure anomalies of the North Atlantic Oscillation, and the long-term growth decline coincided with Iberian-wide drying since the mid-1970s. Climate model simulations not only confirm this negative trend over the last decades but also project drought to continuously increase over the 21st century. Associated ecological effects and socio-economic consequences should be considered to improve adaptation strategies of agricultural and forest management, as well as biodiversity conservation and ecosystem service.

Climate sensitivity of Mediterranean pine growth reveals distinct east-west dipole

The European Mediterranean region is governed by a characteristic climate of summer drought that is likely to increase in duration and intensity under predicted climate change. However, large-scale network analyses investigating spatial aspects of pre-instrumental drought variability for this biogeographic zone are still scarce. In this study we introduce 54 mid- to high-elevation tree-ring width (TRW) chronologies comprising 2186 individual series from pine trees (Pinus spp.). This compilation spans a 4000-km east–west transect from Spain to Turkey, and was subjected to quality control and standardization prior to the development of site chronologies. A principal component analysis (PCA) was applied to identify spatial growth patterns during the network's common period 1862–1976, and new composite TRW chronologies were developed and investigated. The PCA reveals a common variance of 19.7% over the 54 Mediterranean pine chronologies. More interestingly, a dipole pattern in growth variability is found between the western (15% explained variance) and eastern (9.6%) sites, persisting back to 1330 AD. Pine growth on the Iberian Peninsula and Italy favours warm early growing seasons, but summer drought is most critical for ring width formation in the eastern Mediterranean region. Synoptic climate dynamics that have been in operation for the last seven centuries have been identified as the driving mechanism of a distinct east–west dipole in the growth variability of Mediterranean pines.

Pinus nigra (European black pine) as the dominant species of the last glacial pinewoods in south-western to central Iberia: a morphological study of modern and fossil pollen

Aim Our aim was to discriminate different species of Pinus via pollen analysis in order to assess the responses of particular pine species to orbital and millennial-scale climate changes, particularly during the last glacial period. Location Modern pollen grains were collected from current pine populations along transects from the Pyrenees to southern Iberia and the Balearic Islands. Fossil pine pollen was recovered from the south-western Iberian margin core MD95-2042. Methods We measured a set of morphological traits of modern pollen from the Iberian pine species Pinus nigra, P. sylvestris, P. halepensis, P. pinea and P. pinaster and of fossil pine pollen from selected samples of the last glacial period and the early to mid-Holocene. Classification and regression tree (CART) analysis was used to establish a model from the modern dataset that discriminates pollen from the different pine species and allows identification of fossil pine pollen at the species level. Results The CART model was effective in separating pollen of P. nigra and P. sylvestris from that of the Mediterranean pine group (P. halepensis, P. pinea and P. pinaster). The pollen of Pinus nigra diverged from that of P. sylvestris by having a more flattened corpus. Predictions using this model suggested that fossil pine pollen is mainly from P. nigra in all the samples analysed. Pinus sylvestris was more abundant in samples from Greenland stadials than Heinrich stadials, whereas Mediterranean pines increased in samples from Greenland interstadials and during the early to mid-Holocene. Main conclusions Morphological parameters can be successfully used to increase the taxonomic resolution of fossil pine pollen at the species level for the highland pines (P. nigra and P. sylvestris) and at the group of species level for the Mediterranean pines. Our study indicates that P. nigra was the dominant component of the last glacial south-western/central Iberian pinewoods, although the species composition of these woodlands varied in response to abrupt climate changes.

Macrofossils as records of plant responses to rapid Late Glacial climatic changes at three sites in the Swiss Alps

Plant macrofossils from the end of the Younger Dryas were analysed at three sites, Gerzensee (603 m asl), Leysin (1230 m asl), and Zeneggen (1510 m asl). For the first two sites an oxygen-isotope record is also available that was used to develop a time scale (Schwander et al., this volume); dates refer therefore to calibrated years according to the GRIP time scale. Around Gerzensee a pine forest with some tree birches grew during the Younger Dryas. With the onset of the isotopic shift initiating the rapid warming (about 11,535 cal. years before 1950), the pine forest became more productive and denser. At Leysin no trees except some juniper scrub grew during the Younger Dryas. Tree birches, pine, and poplar immigrated from lower altitudes and arrived after the end of the isotopic shift (about 11,487 B.P.), i.e., at the beginning of the Preboreal (at about 11,420 B.P.). Zeneggen is situated somewhat higher than Leysin, but single tree birches and pines survived the Younger Dryas at the site. At the beginning of the Preboreal their productivity and population densities increased. Simultaneously shifts from Nitella to Chara and from silt to gyttja are recorded, all indicating rapidly warming conditions and higher nutrient levels of the lake water (and probably of the soils in the catchment). At Gerzensee the beginning of the Younger Dryas was also analysed: the beginning of the isotopic shift correlates within one sample (about 15 years) to rapid decreases of macrofossils of pines and tree birches.

Construcción de colecciones sociales en bibliotecas iberoamericanas : El caso Pinterest

Este trabajo descriptivo exploratorio se propone detectar y analizar el uso de la red social Pinterest por bibliotecas iberoamericanas. Se analizaron 648 sitios de bibliotecas en la red social y se recopilaron los siguientes datos de cada una: institución a la que pertenecen, ubicación geográfica, tipos de bibliotecas y actividad en el servicio (tipos de tableros, pines que crearon y cantidad de seguidores). Se concluye que el tipo de bibliotecas que más están utilizando esta red son las públicas, populares y universitarias, con un fuerte predominio de las españolas.

Construcción de colecciones sociales en bibliotecas iberoamericanas : El caso Pinterest

Este trabajo descriptivo exploratorio se propone detectar y analizar el uso de la red social Pinterest por bibliotecas iberoamericanas. Se analizaron 648 sitios de bibliotecas en la red social y se recopilaron los siguientes datos de cada una: institución a la que pertenecen, ubicación geográfica, tipos de bibliotecas y actividad en el servicio (tipos de tableros, pines que crearon y cantidad de seguidores). Se concluye que el tipo de bibliotecas que más están utilizando esta red son las públicas, populares y universitarias, con un fuerte predominio de las españolas.

Construcción de colecciones sociales en bibliotecas iberoamericanas : El caso Pinterest

Este trabajo descriptivo exploratorio se propone detectar y analizar el uso de la red social Pinterest por bibliotecas iberoamericanas. Se analizaron 648 sitios de bibliotecas en la red social y se recopilaron los siguientes datos de cada una: institución a la que pertenecen, ubicación geográfica, tipos de bibliotecas y actividad en el servicio (tipos de tableros, pines que crearon y cantidad de seguidores). Se concluye que el tipo de bibliotecas que más están utilizando esta red son las públicas, populares y universitarias, con un fuerte predominio de las españolas.

Promoting mixed stands through conversion treatments. Effect of holm oak coppices thinning on black pine regeneration

The effects of conversion treatments, depending on ecological factors and silvicultural parameters (thinning intensity, thinning type and rotation, among others) have been studied during the last fifteen years in an experimental trial in Central Spain. The general climate is continental Mediterranean; soils are low depth and limy; vegetation is an homogeneous dense coppices of Quercus ilex with isolated Pinus nigra trees. The experimental design (three locations) includes different thinning intensities (from 0 to 100% of extracted basal area). Inventories have been carried out in 1994 and 2010; thinning treatments were done in 1995 and 2011. Analysis of the effects of the conversion treatment show the increment of diameter and height growth rates, the canopy recovery and the stand resprouting, finding differences in these effects between thinning treatments. Besides the induced changes at holm oak stand, the application of conversion treatment clearly changed the woodland dynamics. Fifteen years after the thinnings, floristic composition varied and an abundant pine regeneration was installed in the woodland. In this work we describe the changes between inventories in tree species composition and diameter distribution, specially in the case of black pine. The conversion treatment caused changes in forest dynamics in the short term, increasing biodiversity and diversifying the forest structure. The fast installation of Pinus regeneration suggests the potential of the zone for the establishment of multipurpose mixed Quercus-Pinus stands in wide areas where Quercus species were favoured by human populations for firewood production. Conversion treatment of coppices, with the creation of mixed stands, constitutes a good management alternative for extensive areas and an interesting technique to adaptation to global change.

Palaeobiogeographical perspectives on pinus pinea, a controversial and enigmatic mediterranean pine

The origins of some species of economic importance occurring over the Mediterranean Basin have been a traditional matter of debate that has important implications for land management. The case of Pinus pinea L. (Stone pine) is probably one of the most controversial, due to its documented long-term interaction with humans and its presence as a symbolic tree in certain areas of the Mediterranean (e.g., southwestern Iberia and Tuscany). Among the rest of the Mediterranean pines, several features make this pine unique (it has a characteristic crown shape, an edible kernel, cones that require three years to mature, and a very depauperate genetic diversity across its range). In addition, its palaeoecological information is rather limited, as the taxonomic precision attained by pollen analysts is insufficient for this tree and macroremains (such as kernels or anatomically well preserved wood) are needed to unequivocally detect the species in the fossil record. Recent findings of macrofossils of Pinus pinea in inland Iberia (Duero Basin) extend the late- Holocene range of the species, but the palaeobiogeographical information and the exhaustive genetic data available still suggest a very limited natural area (but still not sufficiently well defined) and a long and intense history of linkage to humans.

Pinus uncinata Ramond ex DC.: Conservation and proposal of management at its southwestern limit of distribution (Castillo de Vinuesa, Soria, Spain)

Pinus uncinata forms forests in the centre and southwest of the Alps and in the subalpine Pyrenees (at around 1700 – 2600 m) (Costa Tenorio et al., 1997). The species reaches the southwestern limit of its distribution at the top of Mount Castillo de Vinuesa (Soria, Spain). The small population on this mountain occupies just 66 ha, but is very important from a geobotanical viewpoint since it is just one of two populations (the other being in the Sierra de Gúdar range in Teruel, Spain) isolated from the main area where the species is found in the Iberian Peninsula (The Pyrenees)

Phenotypic and genetic sources of variability of cavitation resistance in Pinus canariensis

Phenotypic and genetic sources of variability of cavitation resistance in Pinus canariensis

Local variability of serotinous cones in a Canary Island pine (Pinus canariensis) stand

The endemic Canary Island pine (Pinus canariensis) has an effective strategy to counteract fire disturbance in the short term. It has a mixed strategy that combines the presence of serotinous cones and thick barks with the ability to re-sprout from the trunk after a fire, a rare trait in pine species. High frequency of fires in the Canary Islands is related to human action, as natural fires by lightning or vulcan activity have very low frequency; hence, the how and whys of the presence of serotinous cones in the species is still a topic of debate. Previous studies showed that the frequency of serotinous cones varies from stand to stand. Here, we analyzed the presence of serotinous cones at a local scale. We selected a Canary Island pine stand in the transition zone between dry and humid forests in the south of Tenerife. Branches were pruned from 20 trees in order to evaluate the presence of serotinous vs. non-serotinous cones by direct verticile counting on the branches. The opening temperature of serotinous cones was assessed in the laboratory. Percentages of serotinous vs. non-serotinous cones varied from 0 to 93 %, showing high variability between trees. Opening temperatures were very high (above 65 ºC) as compared to other Mediterranean pine species with serotinous cones

Physical data acquisition and PWM signal generation using a microcontroller allowing control for DC motor rotation speed

El objetivo de este proyecto es diseñar un sistema capaz de controlar la velocidad de rotación de un motor DC en función del valor de temperatura obtenido de un sensor. Para ello se generará con un microcontrolador una señal PWM, cuyo ciclo de trabajo estará en función de la temperatura medida. En lo que respecta a la fase de diseño, hay dos partes claramente diferenciadas, relativas al hardware y al software. En cuanto al diseño del hardware puede hacerse a su vez una división en dos partes. En primer lugar, hubo que diseñar la circuitería necesaria para adaptar los niveles de tensión entregados por el sensor de temperatura a los niveles requeridos por ADC, requerido para digitalizar la información para su posterior procesamiento por parte del microcontrolador. Por tanto hubo que diseñar capaz de corregir el offset y la pendiente de la función tensión-temperatura del sensor, a fin de adaptarlo al rango de tensión requerido por el ADC. Por otro lado, hubo que diseñar el circuito encargado de controlar la velocidad de rotación del motor. Este circuito estará basado en un transistor MOSFET en conmutación, controlado mediante una señal PWM como se mencionó anteriormente. De esta manera, al variar el ciclo de trabajo de la señal PWM, variará de manera proporcional la tensión que cae en el motor, y por tanto su velocidad de rotación. En cuanto al diseño del software, se programó el microcontrolador para que generase una señal PWM en uno de sus pines en función del valor entregado por el ADC, a cuya entrada está conectada la tensión obtenida del circuito creado para adaptar la tensión generada por el sensor. Así mismo, se utiliza el microcontrolador para representar el valor de temperatura obtenido en una pantalla LCD. Para este proyecto se eligió una placa de desarrollo mbed, que incluye el microcontrolador integrado, debido a que facilita la tarea del prototipado. Posteriormente se procedió a la integración de ambas partes, y testeado del sistema para comprobar su correcto funcionamiento. Puesto que el resultado depende de la temperatura medida, fue necesario simular variaciones en ésta, para así comprobar los resultados obtenidos a distintas temperaturas. Para este propósito se empleó una bomba de aire caliente. Una vez comprobado el funcionamiento, como último paso se diseñó la placa de circuito impreso. Como conclusión, se consiguió desarrollar un sistema con un nivel de exactitud y precisión aceptable, en base a las limitaciones del sistema. SUMMARY: It is obvious that day by day people’s daily life depends more on technology and science. Tasks tend to be done automatically, making them simpler and as a result, user life is more comfortable. Every single task that can be controlled has an electronic system behind. In this project, a control system based on a microcontroller was designed for a fan, allowing it to go faster when temperature rises or slowing down as the environment gets colder. For this purpose, a microcontroller was programmed to generate a signal, to control the rotation speed of the fan depending on the data acquired from a temperature sensor. After testing the whole design developed in the laboratory, the next step taken was to build a prototype, which allows future improvements in the system that are discussed in the corresponding section of the thesis.

Historia holocena de los pinares montanos de los sistemas Central y Cantábrico: Un objetivo con dos enfoques, biogeográfico y dendroecológico

Los estudios paleoecológicos holocenos basados en macro- y megafósiles encierran un gran valor debido a que su información tiene generalmente carácter local, su origen es conocido, pueden ser datados directamente mediante el método radiocarbónico, y pueden identificarse a un nivel taxonómicamente preciso. Sin embargo son pocas las áreas del Sur de Europa en las que sea conocida una alta densidad de yacimientos con restos leñosos de gran tamaño. En esta tesis, se presentan datos de 53 yacimientos de la sierra de Gredos y de la cordillera Cantábrica (Península Ibérica). Los restos fueron hallados en ambientes variados, como zonas higroturbosas, turberas erosionadas o lagos, y fueron identificadas mediante el estudio de la anatomía de la madera o mediante rasgos morfológicos. En la sierra de Gredos, la evidencia paleobotánica indica la existencia de un panorama relativamente estable a lo largo del Holoceno medio y principio del Holoceno final y sugiere la persistencia, a lo largo de milenios, de un piso de pinares ampliamente distribuído en cotas altas de la sierra. La información obtenida de piñas y frutos mejoran la información taxonómica disponible y revelan la existencia tanto de Pinus sylvestris como de Pinus nigra en estas sierras durante el Holoceno. La datación radiocarbónica, medición de anillos de crecimiento y sincronización preliminar de 26 secciones de troncos de subfósiles demuestran el potencial de este material de las montañas de Iberia central en la obtención de cronologías holocenas de pino. En la cordillera Cantábrica, los datos aportan información espacialmente precisa de distribuciones de ciertas especies arbóreas durante el Holoceno. En las zonas centrales de la cordillera, han sido hallados fundamentalmente restos de pino, mientras que en las zonas más occidentales los pinos estás ausentes y los restos encontrados corresponden a otras especies de caducifolios (Betula, Salix, Quercus) y arbustos (Erica, Fabaceae) Esta información paleobiogeográfica constrasta con la distribución natural actual de Pinus sylvestris y Pinus nigra en el área de estudio. En la sierra de Gredos, la naturalidad de las escasos rodales de pinos que aún persisten ha sido discutida, mientras que en la cordillera Cantábrica, la única especie del grupo que persiste es P. sylvestris y está localizada en unos pocos relictos. El clima pudo haber jugado un papel importante en una primera fase de declive de los pinares durante el Holoceno inicial, mostrado en numerosos registros polínicos de manera casi sincrónica y asociada a una expansión de frondosas. Sin embargo la información histórica disponible y la comparación entre las áreas de distribución de los pinares en el presente, modelizada y en momentos anteriores a la la generalización de la presión antrópica sugiere que durante los últimos dos milenios, la actividad humana ha sido responsable de la desaparición de estas especies como árboles naturales en áreas extensas. ABSTRACTMacro- and megafossil studies provide information of great value in palaeoecology because such evidence is spatially precise, directly radiocarbon dated and usually taxon-specific. However, few areas of southern Europe have a high density of sites with Holocene woody remains. Here, local data from 53 sites in the Gredos Mountains and the Cantabrian Range (Iberian Peninsula) is presented. Woody remains were recovered from mires, eroded peat bogs and lakes and were identified by their wood anatomy or morphological traits. In the Gredos Mountains, palaeobotanical evidence portrays a relatively stable picture of tree distribution over the mid- and beggining of the late-Holocene, and suggests the persistence of a widespread belt of pinewoods. Cones and fruits enlarge the taxonomic information available and reveal that both Pinus sylvestris and Pinus nigra were present locally during the Holocene. Radiocarbon dating, tree ring measurement and preliminary cross-dating of 26 pine sub-fossil logs demonstrate the potential of obtaining a long pine chronology from subfossil wood from the mountains of Central Iberia. In the Cantabrian Range the data provide spatially precise evidence of tree distribution in the region during the Holocene. Pines were mostly identified in the central areas, whereas at the western edge no pine evidence was detected and deciduous trees (Betula, Salix, Quercus) and shrubs (Erica, Fabaceae) were identified. This palaeoecological information contrasts with the current natural distribution ranges of P. sylvestris and P. nigra in the study area. In the Gredos Mountains, the naturality of the few pine stands currently growing has been heavily debated. In the Cantabrian Range P. sylvestris is the only pine species that is today present, and its natural presence is now limited to a few enclaves. Climate may have played a key role in the early-Holocene, as pollen archives document a pine demise that is synchronous with the spread of broadleaved taxa. However, available historical data and the comparison of the reconstructed distribution of pinewoods before extensive human forest disturbance with both present and modelled distributions suggests that during the last two millennia, anthropogenic activity may have removed these species as native trees from a large territory.

Pinos y arte : ensayo de contextualización en la naturaleza desde el Paleolítico a Roma

Al ser la naturaleza objeto de representación artística por el hombre, campos tan diversos como el arte y la ciencia forestal pueden compartir sus orígenes. Los pinos son un género botánico repartido por la cuenca mediterránea capaces de suscitar emociones al haber sido sujetos de lo que fue una innovación cultural. Se propone que los pinos pudieron ser objeto de las primeras representaciones artísticas de los antiguos pobladores de la Península Ibérica. La metodología en la selección de resultados se basa en patrones morfológicos: patrón 1 (plántulas de pino en sus primeras etapas de crecimiento), patrón 2 (dibujos asimilables a ramas de pino) y patrón 3 (dibujos de pinos de gran porte). La presentación de los resultados se estructura en: parte I (referente a las representaciones artísticas estimadas como de pinos en la prehistoria, diferenciando el arte paleolítico del post-paleolítico), parte II (contempla los resultados encontrados en el repertorio iconográfico del arte Íbero y Celtíbero) y parte III (presenta una selección de resultados del arte romano en Hispania). Las diferentes etapas artísticas se articulan comenzando con una introducción, seguida de enfoques multidisciplinares que incluyen una visión histórica del paisaje o de la ecología de la vegetación. A continuación se exponen los resultados de la revisión realizada en cada etapa histórica y el estudio y descripción de las piezas seleccionadas (localización geográfica, datación arqueológica, clasificación genérica de técnica, materiales, dimensiones, iconografía, contexto cultural y procedencia) y por último su discusión en cuanto a su adscripción al género Pinus y a la flora presente en el entorno, caso de ser posible. Esta información se completa con gráficos, diagramas, mapas y tablas situándolas en su contexto arqueológico y cronológico, aportando datos sobre el carácter utilitario, simbólico o ideológico de los pinos, cuya pervivencia se manifiesta en ser protagonistas de gran número de festejos en la España rural de nuestros días. SUMMARY Nature has been represented in paintings since ancient times, which enables fields of study as separate as art and forest science to share a common origin. Pine-tress belong to a botanical genus widely distributed throughout the Mediterranean basin, which are capable of rising emotion and being a representation of what at that time was cultural innovation, subsequently becoming symbols. In this dissertation we hypothesise that pine forest may have been one of the first artistic representations of the ancient dwellers of the Iberian Peninsula. The methodology used for the selection of results is based on morphological patterns, i.e.: Patern 1 (pine seedlings at their first developmental stages), Pattern 2 (drawings associated with pine branches and shoots), and Pattern 3 (paintings of large pine-trees). Results are shown according to the following structure: Part I (relating to prehistoric paintings identified as pines and differentiating Paleolithic from Post-Paleolithic art), Part II (involves the results gathered concerning Iberian and Celtiberian iconographic art) and Part III (including a selection of Roman art in Hispania concerning pine representations). The different artistic periods are linked beginning by an Introduction, followed by a multidisciplinary approach ranging from a historical landscape analysis to plant ecology within a Mediterranean context. Thereafter, results are presented by assessing each historical period and by describing each of the particular art pieces subjected to investigation (geographical location, archaeological date, generic classification of the art technique, materials, dimensions, iconography and cultural context and origin). Finally, the results are discussed according to their ascription to the Pinus genus and when possible, in relation with the surrounding flora. The information provided is complemented with diagrams, maps and tables to enable its understanding within a chronological and archaeological context and providing evidence for the functional, symbolic and ideological character of pines, which are still alive in Spain in the form of many rural feasts with particular kinds of celebrations where this species plays a central role.