Christopher Carcaillet

• PhD
• Professor (Full) at Paris Sciences and Letters (PSL) University

Assisted tree migration has been proposed as a conceptual solution to mitigate lags in biotic responses to anthropogenic climate change. The rationale behind this concept is that tree species currently growing under warmer and drier climates will be more resistant and resilient to the new climatic conditions than tree species naturally growing in c...

Supplementary information about the main text of the article of Michalet et al., 2024, Assisted migration in a warmer and drier climate: less climate buffering capacity, less facilitation and more fires at temperate latitudes?

Fire is a potential significant driver of soil erosion in the Mediterranean area, as it results in the partial removal of vegetation and the alteration of organic matter, affecting soil structure and stability. The erosion of particle sizes is influenced by the intensity and duration of rainfall, regulated by disturbance regimes and vegetation cove...

Supplementary information to support the article of Sayedi et al. 2024, Fire Ecology.

Background The global human footprint has fundamentally altered wildfire regimes, creating serious consequences for human health, biodiversity, and climate. However, it remains difficult to project how long-term interactions among land use, management, and climate change will affect fire behavior, representing a key knowledge gap for sustainable ma...

Il n’y a pas que les humains et les animaux qui migrent. Les arbres le font aussi naturellement, à une vitesse estimée à quelques kilomètres par siècle. Ainsi, via la dispersion de graines, certaines espèces ont pu migrer vers des latitudes plus clémentes, lors des grands changements climatiques passés.Mais face à la rapidité du changement climatiq...

Wildfires are critical socio-ecological features in the Mediterranean basin. In a context of global changes (climate, land use), we questioned whether the wildfire regime was altered in the mountains of Corsica, France. Using tree-ring analysis of fire-scarred trees, we tested for changes in frequency, seasonality, and area. We hypothesized that th...

Supplementary information about the main text of the article Badeau et al. 2024, 202 years of changes in Mediterranean fire regime in Pinus nigra forest, Corsica

Le système de publication scientifique est sous tension : l'accès aux publications doit être libre et gratuit, mais publier a un coût. Historiquement, ce coût revenait aux lecteurs. Désormais, il incombe souvent aux auteurs, permettant un accès gratuit aux lecteurs, avec en 2019 31 % de tous les articles scientifiques publiés qui étaient accessible...

A survey of Pinus cembra (Arolla pine) growing above 2800-m elevation was conducted in an ecoregion of the western Alps, where the highest treeline is at ~ 2650 m. The concepts of treeline and species line are discussed based on these field observations. The species line is the biological limit of a species, with inherited nested historical and cur...

Supplementary information about the article Unsuspected prevalence of Pinus cembra in the high-elevation sky islands of the western Alps

Mountain landscapes are highly heterogeneous due to topography, notably positions along slope and slope shapes, which control ecosystem mechanisms. We hypothesized that tree dieback is controlled by topography, selecting productive and less diverse communities in lower slopes, and stress-resistant and more diverse communities on upper slopes. Under...

The semi-arid forest ecosystems of western Iran dominated by Quercus brantii are often disturbed by wildfires. Here, we assessed the effects of short fire intervals on the soil properties and community diversity of herbaceous plants and arbuscular mycorrhizal fungi (AMF), as well as the interactions between these ecosystem features. Plots burned on...

Human activity has fundamentally altered wildfire on Earth, creating serious consequences for human health, global biodiversity, and climate change. However, it remains difficult to predict fire interactions with land use, management, and climate change, representing a serious knowledge gap and vulnerability. We used expert assessment to combine op...

Here, from macrophylogeographic mtDNA empirical data, we propose a scenario for the evolution and speciation of two important forest trees, European black pine and Scotch pine, and their multiple subspecies and varieties. Molecular clock simulations revealed that INDEL variability in the Pinus mitochondrial genome is relatively old, i.e., from the...

SI of main text about plant macroremains

Sedimentological and biogeochemical measurements were conducted on minerotrophic peat in a wilderness area on a granitic plateau to reconstruct the local ecosystem’s history and clarify the peat’s response to local and global changes. The peat is less than 1900 years old. Its clay and iron (Fe) concentration profiles revealed an increasing atmosphe...

Data from the article: Goutiers, V.; Carcaillet, C. Geo-chemistry and Sedimentology of a Minerotrophic Peat in a Western Mediterranean Mountain Wilderness Area. <Quaternary 2022, 5, 48, doi: 10.3390/quat5040048>. Sedimentological data (granulometry, organic matter), and geochemical data (C, N, P, K, Ca, Mg, S, CEC, pH, weathering proxies, and MTE)...

The model of the maritime pine forest of the Landes de Gascogne (France), which was economically decisive for this region in the 19th century, needs to be rethought. This territory, increasingly populated and shared, is a source of ignition; homogeneous (propagation) maritime pine (flammable) forests should no longer be the only option. Le modèle...

In summer, TV and newspapers often broadcast impressive views of wildfires in Mediterranean forests. These fires are commonly seen as threats to people, their homes, and their property. However, what if wildfires are necessary to sustain the health of some forest plants? Might some plants even need wildfires? Scientists studied this strange issue b...

Background The present article questions the relative importance of local- and large-scale processes on the long-term dynamics of fire in the subalpine belt in the western Alps. The study is based on soil charcoal dating and identification, several study sites in contrasting environmental conditions, and sampling of soil charcoal along the elevatio...

Under climate change, modifications on plants’ growth are expected to be the strongest at species margins. Therein, tree acclimation could play a key role as migration is predicted to be too slow to track shifts of bioclimatic envelops. A requirement is, however, that intra-population genetic diversity be high enough for allowing such adaptation of...

Grant contribution for a PhD

We used bioproxies from paleosoils buried within two aeolian dunes to test hypotheses concerning the origin of dry sandy boreal forests in Canada. These forests are dominated today by Pinus banksiana Lamb. One hypothesis is that too frequent Holocene stand-replacing fires would have transformed the original vegetation through extirpation of suscept...

The present note intends to challenge, based on field observations, the definition of treeline and argues for considering the upper occurrences of tree-species as an integrative result of historical and contemporary processes acting on high-altitude socio-ecosystems. A field survey of Pinus cembra growing above 2800 m asl was conducted, in an ecore...

Changes in community diversity and dynamics after fires in Mediterranean ecosystems are rarely investigated more than a few years after the fire even though pronounced changes can be expected in the longer term due to substitution of canopy species. Pinus halepensis is strongly promoted by wildfire and should therefore be gradually substituted by Q...

The long-term ecological interactions between fire and the composition of dominant trees and shrubs in boreal and cold temperate Fennoscandian forests are still under discussion. We hypothesized that fire-prone taxa should abound during periods and regions characterized by higher fire disturbance, while fire-intolerant taxa should dominate when and...

Although lacustrine sedimentary charcoal has long been used to infer paleofires, their quantitative reconstructions require improvements of the calibration of their links with fire regimes (i.e. occurrence, area, and severity) and the taphonomic processes that affect charcoal particles between the production and the deposition in lake sediments. Ch...

The relationship between Holocene changes in Fennoscandia biomass burning (reconstructed by means of sedimentary charcoal records from lake and peat bogs) and main forest composition (based on pollen reconstructions from the same sites) divided into three different fire sensitivity classes is explored based on the hypothesis that fire-prone species...

Background In Mediterranean mountain socio-ecosystems, both grazing by livestock and the dry season may influence tree regeneration. However, the relative contributions of these drivers are poorly known, even though present and future canopy composition might result from past and present variations in climate and herbivore density. This study aims...

This Policy Brief results from a workshop held at Royal Holloway University of London and funded by PAGES, the Quaternary Research Association (QRA), and Chrono-environnement CNRS/Université de Franche-Comté. The workshop gathered 30 international participants from 15 countries to discuss ongoing challenges on biodiversity conservation and fire pol...

Background: Genetic processes shape the modern-day distribution of genetic variation within and between populations and can provide important insights into the underlying mechanisms of evolution. The resulting genetic variation is often unequally partitioned within species' distribution range and especially large differences can manifest at the ra...

Le projet testera par dendrochronologie la fonction respective des forçages « top-down » (climat : sécheresse, température) et « bottom-up » (usages sylvopastoraux, topographie, exposition, sol) sur les régimes de feu de forêts dans la montagne Corse au cours des derniers siècles. Puis le rôle fonctionnel des feux sur la croissance des arbres sera...

Les forêts « neigeuses », une longue histoire d'adaptation au feu 26 août 2019, 20:44 CEST Les grands incendies qui ont ravagé des millions d'hectares de forêt cet été en Sibérie et l'année précédente en Scandinavie nous l'ont rappelé : les forêts neigeuses ne sont pas épargnées par la menace du feu. Ces forêts froides ne se résument pas aux taïgas...

Des forêts de pin noir en Corse présentent en abondance des traces d’incendies sous la forme de cicatrices à la base des troncs. Ces cicatrices peuvent être datées à l’année près par dendrochronologie (analyse des cernes annuels de croissance du bois), et fourniraient une chronique des feux sur au moins 300 ans. Les analyses statistiques spatiales...

In the boreal forest of eastern North America, the distribution of eastern white cedar (Thuja occidentalis) is characterized by a latitudinal fragmentation gradient from south to north. Marginal populations could be outposts allowing cedar to expand its presence in the north in response to climate change. This study aimed to characterize the spatio...

Key message Whilst livestock has maintained grasslands over centuries in south European mountains, current ungulate densities are insufficient to control tree and forest expansion effectively. The present results based on fir population dynamics and radial/height growth raise questions about the sustainable management of new forests that are former...

Plant leaves host species rich communities of foliar endophytic fungi (FEF). Compared to the other compartments of the plant microbiome, FEF diversity is poorly known. Here we document the communities of FEF associated with the endemic Corsican pine Pinus nigra subsp. laricio at three sites across its natural range and examine the effect of forest...

Fire resistance traits drive tree species composition in surface-fire ecosystems, but how they covary at different scales of variation and with the environment is not well documented. We assessed the covariation of bark thickness, tree height and crown base-to-height ratio across Alpine forests, after accounting for the effects of tree diameter and...

The influence of different drivers on changes in North American and European boreal forests biomass burning (BB) during the Holocene was investigated based on the following hypotheses: land use was important only in the southernmost regions, while elsewhere climate was the main driver modulated by changes in fuel type. BB was reconstructed by means...

Aim Potential fire intensity (PFI) is among the main drivers of fire–vegetation interactions, but how it varies across species ranges is unknown. We test whether PFI and crown fire likelihood (CFL) increase preferentially towards the warm/dry range margins of mountain trees. Location The western Alps. Methods We analysed PFI and CFL patterns acro...

Il est, quelques fois, des avancées scientifiques qui sont de véritables découvertes. C’est ce que deux études conduites dans les Alpes françaises, toutes deux dans le département des Hautes-Alpes, ont révélé. Elles démontrent l’existence de véritables oasis de biodiversité durant la période glaciaire au cœur des massifs parmi les plus hauts des Al...

Up to now, the most widely accepted idea of the periglacial environment is that of treeless ecosystems such as the arctic or the alpine tundra, also called the tabula rasa paradigm. However, several palaeoecological studies have recently challenged this idea, that is, treeless environments in periglacial areas where all organisms would have been ex...

The historical changes of European Black Pine populations size across the whole natural distribution in Europe and Asia Minor was analyzed facing the Plio-Pleistocene climatic fluctuations. Thirteen chloroplast SSRs and SNPs markers have been studied under the assumptions of "neutral evolution". Populations and meta-populations had different histor...

The historical changes of European Black Pine populations size across the whole natural distribution in Europe and Asia Minor was analyzed facing the Plio-Pleistocene climatic fluctuations. Thirteen chloroplast SSRs and SNPs markers have been studied under the assumptions of "neutral evolution". Populations and meta-populations had different histor...

In paleoecology, the function of biomass as a fire driver has become a focus of attention in cold ecosystems, and concerns have been raised about climate in this context. Little is known about the fire frequency and fire–plant relationships during glaciation when woodlands were limited and the climate was cold. Fire history and tree biomass were re...

Documenting succession in forest canopy gaps provides insights into the ecological processes governing the temporal dynamics of species within communities. We analyzed the fruiting patterns of a rare but widely distributed saproxylic macromycete, Xylobolus subpileatus, during the ageing of natural canopy gaps in oak forests. In one of the last rema...

Progresses in reconstructing Earth's history of biomass burning has motivated the development of a modern charcoal dataset covering the last decades through a community-based initiative called the Global Modern Charcoal Dataset (GMCD). As the frequency, intensity and spatial scale of fires are predicted to increase regionally and globally in conjun...

Grazing by livestock and logging are among the main widespread forest uses in mountain forests. Centuries of these anthropogenic disturbances have shaped forests in Europe, especially in the Mediterranean region. Since the 19th century, pastoralism and forestry have experienced deep changes. The present study aims to assess and quantify the effects...

A fuel wood analysis based on the “Principle of Least Effort” helps to decipher the ecological limitations imposed on prehistoric hunter-gatherers. The present study is based on botanical identification of wood charcoal from “Swedish middle Mesolithic” archaeological sites dating from between ca. 9650 and 8300 cal yr BP in northern Sweden, a period...

Tree species responses to climate change will be greatly influenced by their evolutionary potential and their phenotypic plasticity. Investigating tree-rings responses to climate and population genetics at the regional scale is crucial in assessing the tree behavior to climate change. This study combined in situ dendroclimatology and population gen...

The European Black Pine (Pinus nigra Arn.) has a long and complex history. Genetic distance and frequency analyses identified three differentiated genetic groups, which corresponded to three wide geographical areas: Westerns Mediterranean, Balkan Peninsula and Asia Minor. These groups shared common ancestors (14.75 and 10.72 Ma). The most recent sp...

The European Black Pine (Pinus nigra Arn.) has a long and complex history. Genetic distance and frequency analyses identified three differentiated genetic groups, which corresponded to three wide geographical areas: Westerns Mediterranean, Balkan Peninsula and Asia Minor. These groups shared common ancestors (14.75 and 10.72 Ma). The most recent sp...

Forest fires are controlled by local (vegetation, aspect, elevation, land uses) and regional (climate) factors. The role of these factors remains poorly assessed on centennial to millennial time scales. Here, we investigate fire and vegetation history in five subalpine sites over the past 8000 years to determine when, how, and why there were differ...

As the permafrost region warms, its large organic carbon pool will be increasingly vulnerable to decomposition, combustion, and hydrologic export. Models predict that some portion of this release will be offset by increased production of Arctic and boreal biomass; however, the lack of robust estimates of net carbon balance increases the risk of fur...

Aim: Little is known about the understorey flammability of European mountain forests. The aim of this study was to determine the relative effects of climate, vegetation structure and composition on the fuel-driven variation in fire spread and intensity. Location: The western Alps. Methods: Fire spread and intensity were simulated under constant moi...

Current evidences indicate that boreal forest and tundra are exposed to warming. One of the expected results of projected climatic change on trees is a northward shift of biogeographic ranges. In boreal ecosystems, the effects of climate change are expected to be most visible at the species northern margin. Global warming should allow a relaxation...

Forest fire is one of the most critical ecosystem processes in the boreal megabiome, and it is likely that its frequency, size and severity have had a primary role in vegetation dynamics since the Last Ice Age (Kasischke & Stocks 2000). Fire not only organizes the physical and biological attributes of boreal forests, but also affects biogeochemical...

Aim Towards the cold margins of the Northern Hemisphere boreal zone, continuing warming should theoretically provide a longer vegetative season, favouring growth and a northward shift in tree species distribution. The northern distribution of Thuja occidentalis L. (eastern white cedar) is marked by the presence of isolated marginal populations dist...

ABSTRACT: The intensity of cyclic larch budmoth ( Zeiraphera diniana GuenÈe; LBM) outbreaks across the European Alps has been reported to have weakened since the early 1980s. In addition to a warmer climate, changes in land-use cover over modern and historical times may have affected the LBM system. Here, we present tree-ring-based reconstructions...

Key message Our study aims to define isotopic and anatomical responses to fires of P. halepensis . Main results: decrease in tree growth and relative conductivity and increase in water use efficiency. Abstract We investigated the ecophysiological responses of a Pinus halepensis Mill. stand surviving two wildfires in southern France. Basal area, iso...

Assessment of biodiversity in a changing world is a key issue and studies on the processes and factors influencing its history at relevant time scales are needed. In this study, we analyzed temporal trends of plant diversity using fossil pollen records from the North American boreal forest-taiga biome (NABT). We selected 205 pollen records spanning...

This study investigated the fire-vegetation relationship by reconstructing the long-term fire and vegetation dynamics around a small lake in the Mediterranean montane belt on Corsica Island. The vegetation is characterised by forests dominated by Pinus nigra ssp. laricio, an endemic subspecies that is currently threatened. Populations of this taxon...

Using nuclear simple sequence repeats (nuSSRs), we determined the genetic variability in the natural distribution range of maritime pine (Pinus pinaster) in the western Mediterranean region. We analysed the role of global and significant climatic fluctuations in driving the evolutionary diversification of this species. We attempted to determine the...

Fire is a key factor controlling global vegetation patterns and carbon cycling. It mostly occurs under warm periods during which fuel builds up with sufficient moisture, whereas such conditions stimulate fire ignition and spread. Biomass burning increased globally with warming periods since the last glacial era. Data confirming periglacial fires du...

Field application of biochar is intended to increase soil carbon (C) storage. The assessment of C storage potential of biochars lacks methods and standard materials. In this study, we compared the chemical reactivity of biochars and hydrochars and their potential mineralisation before and after physical weathering as one possibility to evaluate the...

Fires have played an important role in creating and maintaining savannas over the centuries and are also one of the main natural disturbances in forests. The functional role of fires in savannas and forests can be investigated through examining sedimentary charcoal in order to reconstruct long-term fire history. However, the relationship between ch...

Relationships between the flammability properties of a given plant and its chances of survival after a fire still remain unknown. We hypothesize that the bark flammability of a tree reduces the potential for tree survival following surface fires, and that if tree resistance to fire is provided by a thick insulating bark, the latter must be few flam...

So far, no phytolith extraction protocols have been tested for accuracy and repeatability. Here we aim to display a phytolith extraction method combining the strengths of two widely used protocols, supplemented with silica microspheres as exogenous markers for quantifying phytolith concentrations. Phytolith concentrations were estimated for samples...

Field application of biochar is intended to increase soil carbon (C) storage. The assessment of C storage potential of biochars lacks methods and standard materials. The reactivity of biochars and hydrochars may be one possible means of evaluating their environmental stability. The aim of this study was to evaluate the reactivity of biochar produce...

1] Paleofire events obtained from the statistical treatment of sedimentary charcoal records rely on a number of assumptions and user's choices, increasing the uncertainty of reconstructio\ns. Among the assumptions made when analyzing charcoal series is the choice of a filtering method for raw Charcoal Accumulation Rate (CHAR raw). As there is no ul...

We developed an algorithm to improve richness assessment based on paleoecological series, considering sample features such as their temporal resolutions or their volumes. Our new method can be applied to both high- and low-count size proxies, i.e. pollen and plant macroremain records, respectively. While pollen generally abounds in sediments, plant...

Strategic introduction of less flammable broadleaf vegetation into landscapes was suggested as a management strategy for decreasing the risk of boreal wildfires projected under climatic change. However, the realization and strength of this offsetting effect in an actual environment remain to be demonstrated. Here we combined paleoecological data, g...

In this era of climate change, understanding past and predicting future fire activity are scientific challenges that are central to the development of sustainable forest management practices and policies. Such objectives, however, are difficult to achieve for several reasons. Uncertainties about future fire activity can be superimposed on the short...

Subalpine ecosystems are mainly affected by surface fires of low to medium intensity. Charcoal production from trees is limited by the duration and the intensity of fires and, thus, by the wood combustibility. Because the combustibility properties of species differ, the functional traits that determine the wood combustibility could explain in part...

Fire-history reconstructions inferred from sedimentary charcoal records are based on measuring sieved charcoal fragment area, estimating fragment volume, or counting fragments. Similar fire histories are reconstructed from these three approaches for boreal lake sediment cores, using locally defined thresholds. Here, we test the same approach for a...

Traditional land use has shaped the Mediterranean region for a long time and has resulted in present-day complex landscapes. The land abandonment dating from the 19th century at a site located in the southwestern Alps (France) makes it possible to analyse how present-day forest stands inherit from past land uses. Tree composition and tree age struc...

Testate amoebae that inhabit peat are sensitive indicators of water table position. In this study, we used testate amoebae in sediments from a mire in the western Alps (Lac du Thyl) to: (1) reconstruct the hydrology of the site over the last 7,000 years, (2) determine how hydrological changes affected testate amoebae diversity and (3) infer past tr...

The significance and cause of the decline in biomass burning across the Americas after AD 1500 is a topic of considerable debate. We synthesized charcoal records (a proxy for biomass burning) from the Americas and from the remainder of the globe over the past 2000 years, and compared these with paleoclimatic records and population reconstructions....