Jesús Julio Camarero

Pyrenean Institute of Ecology, Spanish National Research Council · Conservation of Natural Ecosystems

Purpose of Review The capacity of woody plants to cope with climate change depends on their adjustments to changing environmental conditions by phenotypic plasticity or by genotypic changes (i.e., local adaptation). To determine whether intraspecific trait variation (ITV) translates into resistance or tolerance to drought and eventually how it rela...

Riparian alder forests are threatened by Phytophthora across Europe. Comparative studies of the pathogenicity of Phy-tophthora species are crucial for developing effective management strategies. Although only a limited number of species, particularly P. × alni, lead to tree decline in natural environments, many species demonstrate pathogenicity in...

The Himalayas are one of the most seismically active regions in the world; thus, experiencing frequent catastrophic earthquakes. A growing body of evidence has shown that large earthquakes severely impact on forest ecosystems, particularly in mountain regions. However, little is known about the impact of severe earthquakes on Himalayan forests. Her...

Severe droughts limit tree growth and forest productivity worldwide, a phenomenon which is expected to aggravate over the next decades. However, how drought intensity and climatic conditions before and after drought events modulate tree growth resilience remains unclear, especially when considering the range-wide phenotypic variability of a tree sp...

Key message Abies alba Mill.– Pinus uncinata Ramond. ecotone dynamics are examined along both altitudinal and protection level gradients by combining field inventories and Landsat data. An upward expansion of A. alba to the subalpine belt is observed in the last decades as a result of stand maturation after logging cessation. Context High-mountain...

Ongoing climatic change is threatening the survival of drought-sensitive tree species, such as silver fir (Abies alba). Drought-induced dieback had been previously explored in this conifer, although the role played by tree-level genetic diversity and its relationship with growth patterns and soil microsite conditions remained elusive. We used doubl...

Evapotranspiration demand has increased rapidly as temperatures have risen, affecting forest productivity. Consequently, carbon (C) uptake by forests is being modified; therefore, a more refined knowledge of the relationships between C capture and hydroclimate variability is required, particularly in drought-prone regions. In this study, we analyze...

High-resolution temperature reconstructions in the previous millennium are limited in Northeast Asia, but they are important for assessing regional climate dynamics. Here, we present, for the first time, a 202-year reliable reconstruction of April temperature changes before the millennium volcanic eruption in 946 CE using tree rings of carbonized l...

Riparian forests are among the most dynamic but threatened terrestrial ecosystems. Their dynamism and conservation depend on historical changes in river geomorphology, which can be evaluated through changes in channel sinuosity. However, we lack long-term assessments on sinuosity and how they impact riparian forest composition, tree growth and dead...

The benefits of masting (volatile, quasi-synchronous seed production at lagged intervals) include satiation of seed predators, but these benefits come with a cost to mutualist pollen and seed dispersers. If the evolution of masting represents a balance between these benefits and costs, we expect mast avoidance in species that are heavily reliant on...

Despite the importance of species interactions in modulating plant range shifts, little is known on the responses of coexisting life forms to a warmer climate. Here, we combine a long-term monitoring of cambial phenology in sympatric trees and shrubs at two treelines of the Tibetan Plateau, with a meta-analysis of ring-width series from 344 shrubs...

Key message Reconstruction of needle dynamics reveals prolonged drought legacy effects on crown condition that represent early warnings of drought-induced dieback in Scots pine. Abstract Understanding the mechanisms of drought-induced forest dieback and tree mortality is a priority for predicting forest responses to climate change. However, long-t...

South rear-edge populations of widely distributed temperate and boreal tree species such as birches (Betula pubescens and B. pendula) are considered particularly vulnerable to climate warming, and at the same time they constitute genetic reservoirs of drought-adapted ecotypes. Here, we compared radial growth patterns and responses to climate, river...

Understanding the chemical composition of our planet's crust was one of the biggest questions of the 20th century. More than 100 years later, we are still far from understanding the global patterns in the bioavailability and spatial coupling of elements in topsoils worldwide, despite their importance for the productivity and functioning of terrestr...

Forest plantations are more vulnerable to the stress induced by biotic and abiotic factors than are naturally regenerated forests. These effects can be aggravated by a lack of management in large reforestation areas, and thinning could, therefore, help trees to reduce dieback and tree mortality related to drought. We address this question using a d...

The growth responses to climate variability are still unknown in locally threatened conifers from dry regions, but this information is necessary for improving the conservation of relict populations under increasing aridification. We characterized the radial growth patterns and responses to climate of Tetraclinis articulata, a Cupressaceae tree ende...

Forests around the world are facing climate change. Increased drought stress and severe heat waves in recent decades have negatively impacted on forest health, making them more vulnerable and prone to dieback and mortality phenomena. Although the term vulnerability is used to indicate an increased susceptibility of forests to climate change with a...

Assessing tree growth patterns and deviations from expected climate baselines across wide environmental gradients is fundamental to determine forest vulnerability to drought. This need is particularly compelling for the southernmost limit of the tree species distribution where hot droughts often trigger forest dieback processes. This is the case of...

Humans have shaped open oak forests for centuries through pollarding and grazing. Nowadays, these cultural landscapes face the abandonment of their traditional uses and new threats, including rising temperatures and increasing drought stress, especially in southern Europe. We need precise data on the long-term radial growth changes of these oak woo...

Climate warming may induce growth decline in warm-temperate areas subjected to seasonal soil moisture deficit, whereas increasing atmospheric CO 2 concentration (C a) is expected to enhance tree growth. An accurate understanding of tree growth and physiological processes responding to climate warming and increasing C a is critical. Here, we analyze...

In seasonally dry forests, wildfires can reduce competition for soil water among trees and improve forest resilience to drought. We tested this idea by comparing tree-ring growth patterns of Pinus pinea stands subjected to two prescribed burning intensities (H, high; L, low) and compared them with unburned (U) control stands in southwestern Spain....

The loss of resilience and prolonged recovery times after extreme climate events can be used as early warning signals of impending tipping points or abrupt irreversible changes. However, evidence of such critical slowing down in growth series is still lacking in terrestrial ecosystems under harsh environmental conditions such as alpine shrublands....

Background and aims: The vulnerability and responsiveness of forests to drought is immensely variable across biomes. Intraspecific tree responses to drought in wide-niche breadth species that grow across contrasting climatically environments may provide key information regarding forest resistance and species distribution shifts under climate chang...

Recent drought-induced dieback alters forest dynamics, which are also shaped by past management. In western Pyrenean silver fir (Abies alba) stands, dieback concurs in space and time with the legacies of past management, but the impacts on forest growth, structure and composition are unknown. We aim to disentangle how dieback interacts with the leg...

Climate extremes such as cold spells are becoming more frequent as climate variability increases. However, few studies have evaluated the impacts of winter cold spells on forest cover, tree growth and leaf and sapwood non-structural carbohydrate (NSC) concentrations. We analyzed changes in tree cover using remote sensing data and compared the radia...

Droughts are becoming more frequent in the Mediterranean basin due to warmer conditions. Droughts negatively impact forests growth for several years, often generating negative legacies or carryover effects. However, these legacies differ among tree species, sites and drought characteristics and have been mainly studied considering tree growth or ca...

The Mediterranean region is projected to experience severe drying trends and more extreme hydroclimate events as a consequence of anthropogenic climate change over the next century. In some places this signal may have already emerged from natural variability. Here we provide context for recent and future changes with a new high-resolution (0.5$^o$)...

Increasing intensity and frequency of droughts are leading to forest dieback, growth decline and tree mortality worldwide. Reducing tree-to-tree competition for water resources is a primary goal for adaptive climate silviculture strategies, particularly in reforested areas with high planting density. Yet, we need better insights into the role of st...

Aim Our understanding of the mechanisms that maintain forest diversity under changing climate can benefit from knowledge about traits that are closely linked to fitness. We tested whether the link between traits and seed number and seed size is consistent with two hypotheses, termed the leaf economics spectrum and the plant size syndrome, or whethe...

Background: Plasticity in response to environmental drivers can help trees cope with droughts. However, our understanding of the importance of plasticity and physiological adjustments in trees under global change is limited. Methods: We used the International Tree-Ring Data Bank (ITRDB) to examine 20th century growth responses in conifer trees duri...

Evidence is accumulating that the radial growth of high-elevation Rhododendron shrubs has high dendrochronological potential. However, it remains unclear if the growth responses of alpine Rhododendron shrubs to climate are contingent on site conditions. Herein, the climate–growth relationships of alpine Rhododendron przewalskii Maxim. shrubs were i...

1. It is a challenge to scale-up from simplified proxies to ecosystem functioning since the inherent complexity of natural ecosystems hinders such an approach. One way to address this complexity is to track ecosystem processes through the lens of plant functional traits. Elevational gradients with diverse biotic and abiotic conditions offer ideal s...

Mediterranean riparian forests have been altered by past use and are also negatively impacted by climate and hydrological droughts. However, we lack data on their historical changes in extent combined with multi-proxy, long-term assessments of tree growth and leaf gas exchange responses to climate, drought severity and river flow. These evaluations...

Aims Shifts in xylem phenology directly determine the forest capacity for carbon sequestration. However, a systematic understanding of the spatial patterns and the underpinning drivers in determining the cessation of wood formation ( C cw ) is lacking at a pan‐continental scale. Here, we addressed this knowledge gap by compiling a new dataset of mu...

Hydroclimate affects the radial growth responses of trees, but the drivers of their spatial and population variability are not sufficiently understood. We addressed this issue by sampling several conifer populations located at the same latitude, but at different longitude and elevation in western (W) and eastern (E) Mexican regions. We used dendroe...

Tree phenology is sensitive to climate warming and changes in seasonal precipitation. Long xylogenesis records are scarce, thus limiting our ability to analyse how radial growth responds to climate variability. Alternatively, process-based growth models can be used to simulate intra-annual growth dynamics and to better understand why growth bimodal...

Floodplain forests are sensitive to climate warming and increased drought, as showed by recent oak (Quercus robur) dieback and mortality episodes. However, a comprehensive comparison of coexisting tree species under different climate settings or biomes are lacking. Herein, we compared growth rates, growth responses to climate and drought severity,...

The scientific value of botanical and zoological specimen collections may be disminishes if they are not subjected to strict processes of classification and ordination. In this article we describe the xylotheque hosted at the Zaragoza premises of the Pyrenean Institute of Ecology (IPE-CSIC) and built with the samples provided by the IPE-CSIC dendro...

Intensive livestock management impacts forest and trees in different ways. Pig manure is a major source of nitrogen (N) pollution of surface and ground waters in some European regions such as north-eastern Spain, but it is understudied how manure application impacts agroforestry systems. How pig manure affects tree radial growth and the N cycle was...

Snow cover is one of the most important factors affecting the regeneration and growth of shrubs in cold arctic and alpine ecosystems. In many of these cold regions, climate change in the last century is manifested not only in a rapid rise of temperature, but also in an increase in winter precipitation. For instance, in the Ural Mountains, winter tu...

Climate warming is expected to lengthen the growing season of tree species and enhance radial growth rates. Alternatively, a longer growing season could not lead to improved radial growth if wood production depends more on growth rate than on growing season length. We test these ideas by comparing leaf phenology data and the estimated start and end...

Wood formation during the growing season is shaped by the intra-annual variability of climatic conditions. In the Mediterranean, the cambial activity is seasonally constrained by winter low temperature and summer drought, resulting in bimodal growth patterns. Although bimodal growth is an ecologically important adaptation of woody species to season...

Despite growing interest in predicting plant phenological shifts, advanced spring phenology by global climate change remains debated. Evidence documenting either small or large advancement of spring phenology to rising temperature over the spatio-temporal scales implies a potential existence of a thermal threshold in the responses of forests to glo...

Accurate projections of growing-season duration of trees are crucial in evaluating the capacity of forests to mitigate climate warming through growth and CO2 uptake. However, little is known on how and to what extent the growing season of tree height growth will change under future warming. Herein, we projected the height-growth phenology of Smith...

High-resolution temperature reconstructions in the prior millennium are limited in northeast Asia, but important for assessing regional climate dynamics. Here, we present, for the first time, a reconstruction of April temperature for ~300 years before the Millennium volcanic eruption in 946 AD, using tree rings of carbonized logs buried in the teph...

Drought-induced dieback is a matter of global concern. It has been widely reported and could compromise the climate warming mitigation potential of forests. That is why we need reliable early-warning proxies to achieve better forecasts of forest dieback and tree death. Tree-ring data can provide some of these needed proxies. I propose considering m...

During the past years, growth and productivity of different oak species have been constrained by water shortage in seasonally dry regions such as the Mediterranean Basin. Thinning could improve oak radial growth in these drought-prone regions through the reduction of tree competition for soil water in summer. However, we still lack adequate, long-t...

There is debate on which tree species can sustain forest ecosystem services in a drier and warmer future. In Europe, the use of non-native timber species, such as Douglas fir (Pseudotsuga menziesii [Mirb.] Franco), is suggested as a solution to mitigate climate change impacts because of their high growth resilience to drought. However, the biogeogr...

Drought-induced forest dieback can lead to a tipping point in community dominance, but the coupled response at the tree and stand-level response has not been properly addressed. New spatially and temporally integrated monitoring approaches that target different biological organization levels are needed. Here, we compared the temporal responses of d...

Extreme climate events such as late spring frosts (LSFs) negatively affect productivity and tree growth in temperate beech forests. However, detailed information on how these forests recover after such events are still missing. We investigated how LSFs affected forest cover and radial growth in European beech (Fagus sylvatica L.) populations locate...

Tree species inhabiting riparian forests under Mediterranean climate have evolved to face summer water shortage but may fail to cope with future increases in drought severity. Thus, understanding tree growth phenological variations in response to environmental conditions is necessary to assess the impact of seasonal drought in riparian forests. In...

Local differentiation at distribution limits may influence species' adaptive capacity to environmental changes. However, drivers, such gene flow and local selection, are still poorly understood. We focus on the role played by range limits in mountain forests to test the hypothesis that relict tree populations are subjected to genetic differentiatio...

Climate–atmospheric patterns affect ecological processes. The El Niño Southern Oscillation (ENSO) represents the strongest global source of climate variability at annual scales, but its impacts on Mediterranean forests are still understudied. Here, ENSO signals recorded by river flow and radial growth series of Mediterranean riparian forests are un...

Assessing post-fire recovery is essential to forecast how ecosystems will respond to future warmer conditions and higher fire severity. Such assessments must consider site conditions and the post-fire recovery of trees and shrubs. We used tree-ring data and intrinsic water-use efficiency (WUEi) to quantify the post-fire responses of a tree (Pinus p...

Trees grow at night, when the vapor pressure deficit (VPD) is low enough. Therefore, intra-annual density fluctuations (IADFs) should be formed when the VPD drops below a certain threshold. This idea is tested by assessing climate-latewood IADF relationships in six conifer species under Mediterranean climate conditions. Hourly climate and dendromet...

Key message Pine benefited from a warming climate with increasing recruitment and upslope shifts of alpine treeline but birch treelines were mostly static highlighting the influence of other confounding, local factors. Abstract Alpine treeline is considered as a sensitive indicator to climate change. Given that low temperature is a primary constra...

Pollarded woodlands are iconic components of European rural landscapes. Pollarding is a traditional management technique used to obtain timber and firewood. However, these woodlands are subjected to different stressors in rapidly depopulating rural regions under continental Mediterranean areas where riparian black poplar (Populus nigra) pollards ar...

Plasticity in response to environmental drivers can help trees cope with droughts. However, our understanding of the importance of plasticity and physiological adjustments in trees under global change is limited. We examine 20th century growth responses in Gymnosperm trees during (resistance) and following (resilience) years of severe soil and atmo...

Plain Language Summary The occurrence patterns of seasonal extreme drought and wetness events are dramatically shifting with climate warming. However, how will different seasonal extreme climate regimes affect the bioclimatic sensitivity of tree growth remains poorly understood. In this study, we investigated the sensitivity of tree growth to diffe...

Forest biomass is an important component of terrestrial carbon pools. However, how climate, biodiversity, and structural attributes co-determine spatiotemporal variation in forest biomass remains not well known. We aimed to shed light on these drivers of forest biomass by measuring diversity and structural attributes of tree species in 400-m 2 plot...

Wood encodes environmental information that can be recovered through the study of tree-ring width and wood anatomical variables such as lumen area or cell-wall thickness. Anatomical variables often provide a stronger hydroclimate signal than tree-ring width, but they show a low tree-to-tree coherence. We investigate the sources of variation in tree...

Alteration of forest by climate change and human activities modify the growth response of trees to temperature and moisture. Growth trends of young forests with even-aged stands recruited recently when the climate became warmer and drier are not well known. We analyze the radial growth response of young conifer trees (37–63 years old) to climatic p...