Emilia Gutiérrez

University of Barcelona | UB · Department of Ecology

The new scenarios of climate change in Europe predict an increase of drought in Europe with special emphasis in the Mediterranean Basin. These new environmental conditions will cause an extra stress for temperate species already living at their distribution limit. We focused on a small and isolated Silver Fir (Abies alba Mill.) stand situated at it...

July-to-October temperature variations are reconstructed for the last 800 years based on tree-ring widths from the Cazorla Range. Annual tree-ring width at this site has been found to be negatively correlated with temperature of the previous summer. This relationship is genuine, metabolically plausible, and cannot be explained as an indirect correl...

The increasing carbon dioxide (CO2) concentration in the atmosphere in combination with climatic changes throughout the last century are likely to have had a profound effect on the physiology of trees: altering the carbon and water fluxes passing through the stomatal pores. However, the magnitude and spatial patterns of such changes in natural fore...

Identifying how physiological responses are structured across environmental gradients is critical to understanding in what manner ecological factors determine tree performance. Here, we investigated the spatiotemporal patterns of signal strength of carbon isotope discrimination (Δ(13)C) and oxygen isotope composition (δ(18)O) for three deciduous oa...

Key message Clim ate is the main driver of Aleppo pine radial growth variability irrespective of site pro ductivity, with the climate effects on tree growth more limiting from 1970 onwards. Abstract Forest management adaptation to climate change requires identifying the previously most vulnerable stands and the possible climate impacts on forests....

Individual trees, not forests, respond to climate. Such an individual‐scale approach has seldom been used to retrospectively track the radial growth responses of trees to climate in dendrochronology. The aim of this study was to adopt this individual view to retrospectively assess tree sensitivity to climate warming, and to evaluate and compare the...

Background: The alpine treeline ecotone is regarded as a sensor of the effects of global change on alpine plant communities. However, little is known about how treeline dynamics influence the diversity and composition of alpine plant communities. Such information is necessary to forecast how ascending montane forests may affect the composition of a...

A seasonal period of water deficit characterizes tropical dry forests (TDFs). There, sympatric tree species exhibit a diversity of growth rates, functional traits, and responses to drought, suggesting that each species may possess different strategies to grow under different conditions of water availability. The evaluation of the long-term growth r...

The dieback of Atlas cedar forests observed in the last decade in the Aur�es and Belezma mountains has been linked by the majority of researchers and planners to the drought as a principal factor. In 1880 and 1979, high levels of mortality were reported after severe droughts. Our main objective is to reconstruct dry years based on the relationship...

Detecting and extracting the dominant climatic signal from tree-ring records derived from Mediterranean areas remains challenging because the relation between climate and treegrowth are usually characterized by a complex interplay of temperature and precipitation signals, with high spatial and temporal variability. Although several studies have est...

Global climate is currently warming at an unprecedented rate with potentially profound and widespread effects on the distributions of plant species and ecological communities (IPCC 2007 ; Lenoir et al. 2008) . Mountain ecosystems and their unique biota are particularly sensitive to such changes (Beniston 2003) . In high elevation forests, climate h...

1. It is expected that climate warming will enhance tree growth of mountain conifer forests in cold regions. However, trees have shown unstable, age-related and site-dependent growth responses to climate throughout the past century, but information on the drivers controlling such responsiveness at the site and tree scales is lacking. We evaluated w...

Aging in trees implies a progressive reduction in the growth rate, related to a shortening of the growing period and changes in the photosynthetic capability and efficiency. These changes may continue during the old-growth life stages following the juvenile phase and are reflected in tree-ring properties such as growth increment, density or stable...

May-to-September mean temperatures over the larger Pyrenees area (Northern Spain and Southern France) are reconstructed for the last Millennium from 22 maximum density (MXD) tree-ring chronologies. For the standardization of the tree-ring series, two detrending methods (Regional Curve Standardization (RCS) and 300-yr spline) were combined with and...

Species Distribution Models (SDMs) were employed to assess the potential impact of climate change on the distribution of Pinus uncinata in the Pyrenees, where it is the dominant tree species in subalpine forest and alpine tree lines. Predicting forest response to climate change is a challenging task in mountain regions but also a conservation prior...

Cedar forests area in northeastern Algeria (Aurès) is decreasing by the massive tree mortality. In some localities more than 95% of the trees have recently died (e.g. Boumerzoug in Belezma National Park). Three reported episodes of massive tree mortality in 1880, 1980, and 2000 were attributed to drought at least as the triggering factor. Our main...

Cedar forests area in northeastern Algeria (Aurès) is decreasing by the massive tree mortality. In some localities more than 95% of the trees have recently died (e.g. Boumerzoug in Belezma National Park). Three reported episodes of massive tree mortality in 1880, 1980, and 2000 were attributed to drought at least as the triggering factor. Our main...

An annual-resolved precipitation reconstruction for the last 800 yr in Southern Spain has been performed using stable carbon isotope (δ13C) of Pinus nigra tree rings. The reconstruction exhibits high- to low-frequency variability and distinguishes a Little Ice Age (LIA, AD 1350-1850) characterized by lower averaged rainfall than both in the transit...

Long-term data on radial increment dynamics in Mediterranean species may identify which climatic variables are the main constraints for radial growth and at which temporal scales they act. To this end, we examined stem radial fluctuations in Quercus ilex L., the dominant evergreen oak species in the Western Mediterranean Basin, over a period of 11y...

Alpine tree-line ecotones are characterized by marked changes at small spatial scales that may result in a variety of physiognomies. A set of alternative individual-based models was tested with data from four contrasting Pinus uncinata ecotones in the central Spanish Pyrenees to reveal the minimal subset of processes required for tree-line formatio...

We investigated the tree growth and physiological response of five pine forest stands in relation to changes in atmospheric CO2 concentration (ca) and climate in the Iberian Peninsula using annually resolved width and δ13C tree-ring chronologies since ad 1600. 13C discrimination (Δ≈ci/ca), leaf intercellular CO2 concentration (ci) and intrinsic wat...

In this study we examine the process of spontaneous forestation in the subalpine Pinus uncinata domain. We focus our study on six linked issues, ranging from the diachronic comparison of the landscape through aerial imagery, the demography of Pinus uncinata populations and the response of Pinus seedlings to simulated environmental changes. The land...

We investigated whether vessel time series of Holm oak (Quercus ilex L.), a diffuse to semi-ring-porous species, can record a climatic signal which differs from the signal encoded in tree-ring width (TRW). The study was conducted in ten Q. ilex trees from a coppice stand in northeast Spain. Chronologies of TRW, mean vessel area (MVA) and maximum ve...

Aim Impacts of global change, such as land‐use and climate changes, could produce significant alterations in the elevational patterns of alpine tree line ecotones and their adjacent vegetation zones. Because the responses of the tree line to environmental variations are directly related to successful tree regeneration, understanding recruitment dyn...

Winter 1995–1996 was an exceptional snow avalanche season in the Pyrenees. Núria Valley, at the SE Pyrenees, registered four avalanches that reached a rack railway that runs along the valley floor. One of these avalanche paths, Canal del Roc Roig, was studied by dendrochronological means. Muntán et al. (2004) reported tree-ring evidence for two pre...

The map collection "Mapa de Zones d'Allaus" (MZA) (Avalanche Paths Map) 1:25.000 of the Institut Cartografic de Catalunya (ICC) has been made using different information sources: population inquiry, historical research, terrain features and vegetation checking. Other sources of information allow a higher resolution in the cartography, such as the d...

This dendroclimatological research is based on two close pine forests (Pinus sylvestris and Pinus uncinata) located at the Northern Iberian System (Spain), and three tree-ring variables (ring widths, δ 13C and δ 18O). The climate-tree growth system was assessed at local and regional scales using three climate datasets. Calibration of tree-ring reco...

A regional study of snow avalanche processes was undertaken in the SE Pyrenees. Dendrogeomorphology was used to date and reconstruct large-scale snow avalanche events that occurred in the last four decades. Dendrochronological analyses yielded the dates of nine winters when avalanches occurred in the recent past in six studied avalanche paths. Some...

Aims Alpine tree line ecotones are harsh environments where low temperatures constrain tree regeneration and growth. However, the expected upward shift of tree line ecotones in response to climate warming has not been ubiquitous. The lack of coupling between tree line dynamics and climate warming might be explained by factors other than climate var...

Aims: The upper elevation limit of forest vegetation in mountain ranges (the alpine treeline ecotone) is expected to be highly sensitive to global change. Treeline shifts and/or ecotone afforestation could cause fragmentation and loss of alpine habitat, and are expected to trigger considerable alterations in alpine vegetation. We performed an analy...

1 RESUMEN La presión social en los Pirineos se ha incrementado notablemente en los últimos años. En zonas mon-tañosas alpinas, los aludes de nieve representan un peligro potencial para personas y bienes. Para una mejor prevención es necesario conocer las zonas susceptibles y la dinámica de aludes. Esto requiere una inspección del territorio y el es...

This paper examines tree-ring width and δ13C chronologies from a network of five Iberian pine forests to determine their sensitivity to climate variability under different site conditions. Interseries comparisons revealed better and more homogenous agreement among δ13C records than among tree-ring width series of the different sites. This suggests...

Summary • Many studies in northern Europe, North and South America, describe regional trends of population densification at altitudinal and polar tree lines during the 20th century. The purpose of this study was (1) to ascertain if this regeneration enhancement is present across the alpine ecotones of the Pyrenees, (2) if synchronous recruitment tr...

Erratum to: Clim Dyn DOI 10.1007/s00382-007-0349-3Because of misunderstanding between authors of the paper and some data providers, we are responsible for some omission in the authors list and acknowledgements.So we want to give here a new author list:A. Nicault, S. Alleaume, S. Brewer, M. Carrer, P. Nola, E. Guttierez, J.L. Edouard, C. Urbinati an...

Background: Pyrenean timberlines, lowered to various extents through ancient land use, are expected to rise due to abandonment of land use and climate warming.Aims: To provide a comprehensive survey of the timberline in the Catalan Pyrenees, at the landscape, plant community, and tree population levels.Methods: We assessed the present location of t...

Wildfires have decimated forests of Pinus nigra in the Mediterranean Basin in recent decades, but little is known about the fire ecology of this native species. We sampled three small relict forest sites on Sierra Turmell, Castellón, Valencia, northeastern Spain, to determine forest structure and past fire events. The forest was characterized by re...

1.-¿Qué es la dendrocronologia? 2.-Los árboles registran el paso del tiempo 2.1.-Características peculiares de los árboles 2.2.-El crecimiento de los árboles 2.3.-La formación de los anillos 2.4.-Tipos de anillos: estructura de la madera 2.5.-El ritmo de crecimiento: regiones templadas, tropicales y mediterráneas 2.6.-La sensibilidad del cámbium a...

En este trabajo se estudia la formación mensual del anillo del tronco, la caída de acículas y la elongación de las ramas en poblaciones de Pinus sylvestris L. y Pinus uncinata Ram. en el Pirineo Central Español durante 1993. La formación del anillo se produce de principios de junio hasta final de septiembre, si bien la mayoría de su crecimiento se...

Describimos el patrón espacial de un ecotono bosque subalpino-pastos alpinos, que incluye los límites altitudinales del bosque y del árbol, dominado por Pinus uncinata Ram. y localizado en los Pirineos Centrales. Situamos una parcela rectangular (30 x 140 m) cruzando el ecotono con su lado mayor paralelo a la pendiente. Para cada individuo de R unc...

1] We present the first European network of tree ring d 13 C and d 18 O, containing 23 sites from Finland to Morocco. Common climate signals are found over broad climatic-ecological ranges. In temperate regions we find positive correlations with summer maximum temperatures and negative correlations with summer precipitation and Palmer Drought Sever...

Pinus leucodermis (=P. heldreichii var. leucodermis) is widespread in the Balkan Peninsula and is present as a post-glacial relict in Southern Italy. The oldest Italian populations of this species are located at high elevation in the National Park of Pollino, where grazing and logging had endangered their survival, especially during the 20th centur...

To infer future changes in the distribution of tree species in response to climatic variability, we need an understanding of the recruitment dynamics and their climatic controls at the species' distribution limit. We studied the recruitment processes in an isolated population of Pinus uncinata Ram. located at the southwestern limit of the species'...

To infer future changes in the distribution of tree species in response to climatic variability, we need an understanding of the recruitment dynamics and their climatic controls at the species’ distribution limit. We studied the recruitment processes in an isolated population of Pinus uncinata Ram. located at the southwestern limit of the species’...

Tree populations located at the geographical distribution limit of the species may provide valuable information about tree-growth response to changes on climatic conditions. We established nine Pinus nigra, 12 P. sylvestris and 17 P. uncinata tree-ring width chronologies along the eastern and northern Iberian Peninsula, where these species are foun...

In Mediterranean climates trees may go through two periods of dormancy, resulting in special anatomical features such as false rings and other intra-annual density fluctuations (IADFs). In this paper, ring growth and the presence of IADFs were studied in Pinus pinea L. growing in the coastal and inland regions of Alentejo (southern Portugal). In or...

Study of the regeneration of mountain pine at the upper limits of the forest zone. These are the preliminary results of a study of the regeneration of mountain pine (Pinus uncinata) in the Alt Pirineu Natural Park. This is part of the more general project VULPIBOS (VULnerabilitat del paisatge supraforestal pirinenc davant de l'ascens del límit supe...

Dendrogeomorphological studies for natural hazards research in the Iberian Peninsula (Spain and Andorra).

We developed a spatially explicit and individual‐based simulation model describing the dynamics of tree populations across treeline ecotones. Our aims were to identify minimal factors and processes able to generate treeline types with abrupt vs. smooth transitions in different variables (tree height, age, density), to investigate the role of positi...

Over the last three years, 16 European isotope labs collaborated in the EU project ISONET (co-ordinator: G. Schleser, http//www.isonet-online.de) on developing the first large-scale network of δ13C, δ18O and δ2H in from oak, pine and cedar tree-rings, covering sites from Fennoscandia to the Mediterranean region. The sampling design considered not o...

Aim To forecast the responses of alpine flora to the expected upward shift of treeline ecotones due to climatic warming, we investigated species richness patterns of vascular plants at small spatial scales across elevational transects. Location Richness patterns were assessed at local scales along the elevational gradient in two undisturbed treelin...

Tree populations located at the geographical distribution limit of the species may provide valuable information about the response of tree growth to climate warming across climatic gradients. Dendroclimatic information was extracted from a network of 10 silver-fir (Abies alba) populations in the south-western distribution limit of the species (Pyre...

Study of the Mountain Pine regeneration at treeline. The study of mountain pine (Pinus uncinata) regeneration is performed inside the limits of the Parc Natural de l’Alt Pirineu and is part of the VULPIBOS project (Sensitivity of supra-forest landscape of the Pyrenees due to treeline uprising). The aim of the study is to determine the most limiting...

Spatial and temporal dinamics of the upper ecotone of the Mountain Pine. Climatic change, increased emissions of carbon dioxide and nitrate depositions, as well as land-use changes can affect treeline dynamics. Several studies show that subalpine treeline populations can be used to monitor ongoing global planetary change, thus Pyrenean subalpine mo...

L’objectiu de l’Ecologia de segon curs de llicenciatura de Biologia és entendre com les relacions de les espècies entre elles i amb les condicions ambientals existents expliquen certes regularitats en la distribució i l’abundància dels individus de les diverses espècies. L’aproximació d’aquestes pràctiques és procurar una descripció abreujada i exp...

Aim To infer future changes in the distribution of isolated relict tree populations at the limit of a species’ geographical range, a deep understanding of the regeneration niche and the spatial pattern of tree recruitment is needed. Location A relict Pinus uncinata population located at the south‐western limit of distribution of the species in the...

Within the EU-Project ISONET (co-ordinator: G. Schleser, http://www.isonet-online.de), 16 partner institutions collaborate to develop the first large-scale network of stable isotopes (C, O and H), integrating 25 European tree sites reaching from the Iberian Peninsula and southern Italy to Fennoscandia. Key species are oak and pine. The sampling des...

The evergreen Nothofagus betuloides and deciduous Nothofagus pumilio live close together in Tierra del Fuego. The fact that these two species rarely form mixed forests suggests that the soil factor can contribute to the distribution of two species on a local scale. Most of these forests are undisturbed; therefore, soil characteristics may reflect b...

We performed a spatiotemporal analysis of a network of 21 Scots pine (Pinus sylvestris) ring-width chronologies in northern Fennoscandia by means of chronology statistics and multivariate analyses. Chronologies are located on both sides (western and eastern) of the Scandes Mountains (678N–708N, 158E–298E). Growth relationships with temperature, pre...

Treeline ecotones are regarded as sensitive monitors of the recent climatic warming. However, it has been suggested that their sensitivity depends more on changes in tree density than on treeline position. We study these processes and the effect of climate, mainly air temperature, on tree recruitment and recent treeline dynamics. We selected three...

Historical data about ancient avalanches are scarce in the Pyrenees. Dendrochronology can provide new data about past avalanches and their return period, but up to now little research has been carried out with this purpose. The Aludex project aims to obtain information about the frequency and extent of extreme avalanches, using a dendrochronologica...

valanche hazard maps of high accuracy are difficult to produce. For land-use planning and management purposes, a good knowledge of extreme run-out zones and frequencies of avalanches is required. In the present work, vegetation recognition (especially focused on Pinus uncinata trees) and dendrochronological techniques are used to characterize avala...

The aim of this paper is to provide a general and detailed review of the external ef- fects of avalanches on forests and trees and their reaction and corresponding tree-ring features. For the well-known avalanches in 1996 in the Pyrenees, we have been able to establish the correspondence between tree growth form and tree-ring signals mainly on moun...

History of soil use influences the association of plant species thus it must be reflected in the diversity of the vegetation under post-fire regeneration. Plant communities were compared to verify this hypothesis on abandoned terraces and outcrop slopes in Valencia, Spain. Regeneration of the vegetation of "matorral" with Ulex parviflorus was sampl...