Pierre Mérian

Institut national de l’information géographique et forestière | IGN · Laboratory of Forest Inventory (Laboratoire de l'Inventaire Forestier)

Tree genetic makeup may provide an important control of growth dynamics; however, no studies have previously attempted to evaluate its effects in natural trembling aspen stands. In this study, we examined the relative contribution of genetics (i.e. clonal diversity, observed heterozygosity) and environmental conditions (i.e. insects, climate) on as...

Une étude comparative de 151 peuplements purs et mélangés de sapin pectiné dans le massif vosgien détermine la complémentarité d’utilisation des ressources face aux contraintes environnementales, sécheresse notamment. Certaines espèces adaptent leur usage de la ressource différemment suivant la compétition ou l’accès aux ressources d’eau. Le sapin...

Temporal instability of forest sensitivity to climate has been evidenced at high elevations and latitudes, and in Mediterranean contexts. Investigations under temperate conditions, where tree growth is under the dual control of temperature and drought, are scarce and could provide valuable information about the ability of forest to cope with climat...

Sessile oak is among the major species in European temperate forests, both in terms of spatial distribution and economic value. In spite of this, research on sensitivity of sessile oak growth to climate is confined to a number of local studies (on the scale of a forest or region). Its scope does not enable the spatial variation of this sensitivity...

Regional chronology and climate-growth relationships assessment are known to be sensitive to sampling effort. To disentangle the respective benefits of increasing whether the number of plots or the number of trees per plot when investigating climate-growth relationships under temperate conditions, we propose to simulate samples from a set of 84 plo...

In dendroecology, sampling effort has a strong influence of both regional chronology properties and climate–tree growth relationships assessment. Recent studies evidenced that decreasing sample size leads to a weakening of the bootstrapped correlation coefficients (BCC). The present analysis focused on the risk of mis-estimating the significance of...

In most dendroecological studies, climate–tree growth relationships are established for trees growing on pure stands. However, response to climate may be affected by inter-species interactions and local constraints, which beg the question of the effect of mixture on tree growth response under various ecological conditions. To assess these effects,...

This report (in French) presents the main principles and methods used in dendrochronology. This report is mainly addressed to young researchers and students.

Temporal instability of climate signal in tree-ring width of the five dominant species (Pinus nigra ssp. nigra, P. sylvestris, P. uncinata, Abies alba, Fagus sylvatica) growing under Mediterranean mountainous climate was studied over the last century (1910-2004). To disentangle the tree–climate–site complex, the effects of both soil water availabil...

Temporal instability of climate signal in tree-ring width of the five dominant species (Pinus nigra ssp. nigra, P. sylvestris, P. uncinata, Abies alba, Fagus sylvatica) growing under Mediterranean mountainous climate was studied over the last century (1910-2004). To disentangle the tree–climate–site complex, the effects of both soil water availabil...

In temperate conditions, studies dealing with spatio-temporal instabilities in climate sensitivity of forest tree species are scarce and often led at local and regional scales, which prevents from drawing global responses to the environment and its variations. The dendrochronological dataset merging (more than 4500 cored trees) allowed analyzing th...

Temporal instability of climate signal in tree-ring width of the five dominant species (Pinus nigra, P. sylvestris, P. uncinata, Abies alba, Fagus sylvatica) growing under Mediterranean mountain climate was studied over the last century (1910-2004). To disentangle the tree–climate–site complex, the effects of both soil water availability (dry, mesi...

Dendroecology is based on the estimation of target population climate sensitivity from a finite number of trees (N). Recent studies evidenced a sample-size-related bias in the climate-tree growth relationships estimations, decreasing sample size leading to a weakening of the bootstrapped correlation coefficients. The present analysis pointed out th...

Study 1 In most dendroecological studies, climate–growth relationships are established for trees growing on pure stands. However, response to climate may be affected by inter-species interactions and local constraints which begs the question of the effect of mixture on tree growth response under various ecological conditions. To assess these effect...

Existing literature investigates the effect of the number of cored trees per plot (N) on chronology statistics. The present study sought to highlight (i) the effect of N on the reliability of both chronology and climate–growth relationships and (ii) its variability across five European tree species with differentiated ecophysiological patterns. Fif...

Temporal instability of forest climate-growth relationships has been evidenced at high elevations and latitudes, and in Mediterranean contexts. Investigations under temperate conditions, where growth is under the control of both winter frost and summer water stress, are scarce and could provide valuable information about the ability of forest to co...

Le réchauffement important déjà observé en Europe et en France, et les prévisions à la fin du XXe siècle questionnent la communauté forestière sur la pérennité des espèces et des écosystèmes dans ce contexte en évolution rapide. L’analyse de la réponse des essences au climat peut se faire par des approches dendroclimatologiques dans lesquelles les...

In most dendrochronological studies, climate–growth relationships are established on dominant trees to minimize non-climatic signals. However, response to environmental factors may be affected by tree-size, which begs the question of the representativeness of dominant trees on the stand level. To highlight the variations in climate–growth relations...

Significant warming already observed in Europe and in France together with predictions made at the end of the 20th century raise questions in the forestry and forest-based community about the sustainability of species and ecosystems in this rapidly changing context. A dendroclimatological approach can be adopted to analyse the response of species t...

The influence of climate on the radial growth of 63 mature stands (1879 trees) growing under different climatic and soil conditions was investigated using chronologies developped from the French Network RENECOFOR. The relationships between climate and ring widths were analyzed using extreme growth years and response functions analysis (1949-1994)....

The growth response of sessile oak to extreme climatic years has been investigated from 1914 to 1993 using extreme years growth, i.e. pointer years. 31 mature and pure stands were cored in northern France (720 trees), under varied climates, from oceanic to semi-continental conditions. The analysis has highlighted similarities in growth characterist...

The influence of climate on the radial growth of 63 mature stands (1879 trees) growing under different climatic and soil conditions was investigated using chronologies developped from the French Network RENECOFOR. The relationships between climate and ring widths were analyzed using extreme growth years and response functions analysis (1949-1994)....

The growth response of sessile oak to extreme climatic years has been investigated from 1914 to 1993 using extreme years growth, i.e. pointer years. 31 mature and pure stands were cored in northern France (720 trees), under varied climates, from oceanic to semi-continental conditions. The analysis has highlighted similarities in growth characterist...