Application of confocal laser scanning microscopy in dendrochronology

We used the Confocal Laser Scanning Microscope (CLSM) Olympus LEXT OLS5000 for non-destructive observation and image analysis of wood anatomy traits in growth layers of tree species from different climatic zones. In European beech (Fagus sylvatica), where tree rings can generally be recognised, we discuss the changes in tree-ring structure due to adverse effects (insect attacks). Growth layers in Mediterranean Aleppo pine (Pinus halepensis) from south-eastern Spain are not always annual and contain numerous intra-annual density fluctuations (IADFs). Ocote pine (Pinus oocarpa) growing at high elevation in Honduras showed growth layers with clear growth ring boundaries and IADFs. In both pines, CLSM allowed us to recognise and measure tracheid parameters to define density fluctuations. In tropical true mahogany (Swietenia macrophylla) from Venezuela and cedrela (Cedrela odorata) from Costa Rica, we studied the growth layers with variable dimensions of vessels demarcated by marginal axial parenchyma

Contrasting Patterns of Tree Growth of Mediterranean Pine Species in the Iberian Peninsula

Wood formation is the primary biological process through which carbon is durably sequestered in woody plants, and is thus a major contributor to mitigate climate change. We analyzed the tree growth patterns of four conifer species across the Iberian Peninsula (IP) based on a dense dendrochronological network (179 sites) combined with a high resolution climate dataset. Generalized linear-mixed models were used to predict the potential tree growth of different pine species under different climate conditions considering different age classes. We found a strong age dependency of tree growth, significant variations across the climate gradients, and a significant interaction of both age and climate effects on the four species considered. Overall, Pinus halepensis was the species with the highest climate sensitivity and the highest growth rates in all age classes and across its distribution area. Due to its stronger plastic character and its potential adaptability, Pinus halepensis was demonstrated to be the most suitable species in terms of tree growth and potentiality to enhance carbon sequestration in the IP. Since its potential distribution largely exceeds its actual distribution, P. halepensis arises as a key species to cope with future climate conditions and to keep fixing carbon regardless of the climatic circumstances

When Density Matters: The Spatial Balance between Early and Latewood

Understanding the influence of the current climate on the distribution, composition, and carbon storage capacity of Mediterranean tree species is key to determining future pathways under a warmer and drier climate scenario. Here, we evaluated the influence of biotic and environmental factors on earlywood (EW) and latewood (LW) growth in Aleppo pine (Pinus halepensis Mill.). Our investigation was based on a dense dendrochronological network (71 sites), which covered the entire distribution area of the species in the Iberian Peninsula (around 119.652 km2), and a high-resolution climate dataset of the Western Mediterranean area. We used generalized linear-mixed models to determine the spatial and temporal variations of EW and LW across the species distribution. Our results showed an intense but differentiated climatic influence on both EW and LW growth components. The climatic influence explained significant variations across the environmental gradients in the study area, which suggested an important adaptation through phenotypic plasticity and local adaptation to varying climatic conditions. In addition, we detected a clear spatial trade-off between efficiency and safety strategy in the growth patterns across the species distribution. Additionally, in more productive areas, the trees presented a higher proportion of EW (more efficient to water transport), while, in more xeric conditions, the LW proportion increased (more safety to avoid embolisms), implying an adaptation to more frequent drought episodes and a higher capacity of carbon depletion. We therefore concluded that Mediterranean forests adapted to dryer conditions might be more efficient as carbon reservoirs than forests growing in wetter areas. Finally, we advocated for the need to consider wood density (EW/LW proportion) when modeling current and future forest carbon sequestrations

Creación y análisis de una red dendroclimática de pinus halepensis mill. en el ámbito mediterráneo

Ponencia presentada en: VII Congreso de la Asociación Española de Climatología: clima, ciudad y ecosistemas, celebrado en Madrid entre el 24 y 26 de noviembre de 2010.[ES]En este trabajo presentamos los avances en el proceso de creación de una densa red de cronologías de Pinus halepensis en la Península Ibérica. El análisis preliminar de esta red que actualmente incluye 28 cronologías, sugiere que la diversidad de regímenes climáticos y la alta variabilidad de las dinámicas temporales de los mismos se traducen en una gran variabilidad en las respuestas dendroclimáticas. Esta inestabilidad espacial observada sugiere a su vez que las relaciones clima-crecimiento ahora observadas pueden estar están sujetas a cambios en la medida que las condiciones climáticas se vean modificadas.[EN]In this article we present advances in the development of a tree-ring network of Pinus halepensis Mill. for the Mediterranean fringe of Spanish peninsula. Our results based on 28 available chronologies show large phenotypic plasticity in P. halepensis linked to climate variability and, in particular, highlight the ability of this species to adapt its growth rhythm to various climate regimes. This finding reveals an high instability in climate-growth relationships and, consequently that important modifications in the climate-growth relationship may be expected in future climates.Ministerio Ciencia y Tecnología (Proyecto CGL2008-05112-C02 y Gobierno de Aragón (Grupo de Investigación “Clima, Agua, Cambio Global y Sistemas Naturales, BOA 69, 11-06-2007)

Missing rings in Pinus halepensis

Climate predictions for the Mediterranean Basin include increased temperatures, decreased precipitation, and increased frequency of extreme climatic events (ECE). These conditions are associated with decreased tree growth and increased vulnerability to pests and diseases. The anatomy of tree rings responds to these environmental conditions. Quantitatively, the width of a tree ring is largely determined by the rate and duration of cell division by the vascular cambium. In the Mediterranean climate, this division may occur throughout almost the entire year. Alternatively, cell division may cease during relatively cool and dry winters, only to resume in the same calendar year with milder temperatures and increased availability of water. Under particularly adverse conditions, no xylem may be produced in parts of the stem, resulting in a missing ring (MR). A dendrochronological network of Pinus halepensis was used to determine the relationship of MR to ECE. The network consisted of 113 sites, 1,509 trees, 2,593 cores, and 225,428 tree rings throughout the distribution range of the species. A total of 4,150 MR were identified. Binomial logistic regression analysis determined that MR frequency increased with increased cambial age. Spatial analysis indicated that the geographic areas of south-eastern Spain and northern Algeria contained the greatest frequency of MR. Dendroclimatic regression analysis indicated a non-linear relationship of MR to total monthly precipitation and mean temperature. MR are strongly associated with the combination of monthly mean temperature from previous October till current February and total precipitation from previous September till current May. They are likely to occur with total precipitation lower than 50 mm and temperatures higher than 5°C. This conclusion is global and can be applied to every site across the distribution area. Rather than simply being a complication for dendrochronology, MR formation is a fundamental response of trees to adverse environmental conditions. The demonstrated relationship of MR formation to ECE across this dendrochronological network in the Mediterranean basin shows the potential of MR analysis to reconstruct the history of past climatic extremes and to predict future forest dynamics in a changing climate

Cuantificación de los gradientes climáticos altitudinales en la vertiente norte del macizo del Moncayo a partir de una nueva red de estaciones automáticas en altura

Ponencia presentada en: VIII Congreso de la Asociación Española de Climatología celebrado en Salamanca entre el 25 y el 28 de septiembre de 2012.[ES]Uno de los problemas de la investigación del clima en áreas de montaña es el de la escasez de observatorios. En España sólo 63 registran a más de 1.500 msnm. En este trabajo presentamos los primeros resultados obtenidos de la red automática de observatorios instalada en el año 2009 en el Macizo del Moncayo dentro del proyecto El Parque Natural del Moncayo como observatorio del cambio global (GA-LC-031/2010). Las estaciones se localizan en la ladera norte del macizo a 1.050 y 1.750 msnm. Esos datos han servido para completar la escasa información climática existente en la zona y construir un gradiente climático altitudinal para la vertiente norte del macizo, numerosas veces descrito pero no cuantificado.[EN]One of the main problems of climate research in mountain areas is the scarcity of weather stations. In Spain, only 63 recorded are more than 1,500 meters above sea level. In this work we present the first results of the automatic weather stations installed in 2009 in the Moncayo area (NE of Spain) within the project GA-LC-031/2010. The weather stations are located on the northern slope of the mountain at 1,050 and 1,750 meters above sea level. These data have provided information to complete the existing climate data in the area and calculate an altitudinal climatic gradient to the slopes of the mountain, many times described but not quantified.DGA-La Caixa, (Proyecto: GA-LC-031/2010); Gobierno de Aragón (Grupo de Investigación “Clima, Agua, Cambio Global y Sistemas Naturales, BOA 69, 11-06-2007)

Identificación de la influencia climática en el crecimiento secundario del Pinus halepensis Mill. a partir del estudio de la madera temprana y tardía

Ponencia presentada en: VIII Congreso de la Asociación Española de Climatología celebrado en Salamanca entre el 25 y el 28 de septiembre de 2012.[ES]Una de las características específicas del Pinus halepensis Mill. es la plasticidad fenológica que ofrece su crecimiento, manifestada en dos ciclos anuales de carácter equinoccial. Los estudios dendroclimáticos tradicionales identifican la relación entre el clima y el crecimiento de esta especie a partir del grosor anual del anillo, método que puede enmascarar las diferencias en la respuesta del árbol frente a las condiciones térmicas y pluviométricas en esos dos periodos. El objetivo del trabajo que aquí presentamos es el de analizar si a partir del análisis del grosor de la madera temprana (earlywood) y la madera tardía (latewood) de los anillos de crecimiento anual del P. halepensis pueden detectarse respuestas diferenciales de la especie frente al clima en cada uno de esos periodos fundamentales de su crecimiento. Para ello se dispone de 28 cronologías localizadas en la vertiente mediterránea que cubren la práctica totalidad del rango climático de distribución natural de P. halepensis en España, un rango amplio en razón de la plasticidad ecológica antes señalada.[EN]The phenological plasticity in tree growth is recognized to be one of the characteristics of Pinus halepensis Mill., which growth may be divided in two annual cycles. The traditional dendroclimatic studies usually identify the relationship between climate and growth of this species from the annual tree-ring widths which may hide different influences of different climate elements over these two periods. The objective of the present study is to determine the influence of seasonal climatic conditions on earlywood and latewood, and to find out if such seasonal information derived from annual tree rings can give us a better interpretation and identification of climate-growth relationships on the seasonal scale in P. halepensis. For this purpose we used 28 chronologies from the Mediterranean area covering almost all the climatic range of natural distribution of P. halepensis in Spain, a wide range because of the aforementioned ecological plasticity.Ministerio Ciencia y Tecnología (Proyecto CGL2008-05112-C02), DGA-La Caixa, (Proyecto: GA-LC- 031/2010); Gobierno de Aragón (Grupo de Investigación “Clima, Agua, Cambio Global y Sistemas Naturales, BOA 69, 11-06-2007)

Reconstrucción de temperaturas a escala diaria en el Parque Nacional del Moncayo (España)

Ponencia presentada en: IX Congreso de la Asociación Española de Climatología celebrado en Almería entre el 28 y el 30 de octubre de 2014.[ES]El presente trabajo muestra una metodología para reconstruir series completas de temperatura máxima y mínima diarias a partir de modelos regresivos diarios y locales utilizando los metadatos inherentes a los datos climáticos: latitud, longitud y altitud. Se han utilizado 66 observatorios del conjunto del Macizo del Moncayo procedentes de las redes de la Agencia Estatal de Meteorología, la Confederación Hidrográfica del Ebro y el Parque Natural del Moncayo, cubriendo un rango altitudinal de 2.000 metros y un periodo temporal desde 1950 hasta 2012.[EN]Present work shows a new methodology to reconstruct complete maximum and minimum temperature series from regressive daily and local models using inherent metadata of climatic data: latitude, longitude and altitude. 66 observatories in whole Moncayo massif have been used from different networks: Spanish Meteorological Agency, Ebro River Basin, and Moncayo Natural Park, covering an altitudinal range of 2,000 meters and a temporal period from 1950 to 2012