Le dépérissement du chêne en forêt de Tronçais Les causes écologiques

Becker, Michel; Lévy, Ghyslain

doi:10.1051/forest:19820407

Cited by 49 publications

(38 citation statements)

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“…In a study of the influence of the intense 1985-1988 drought on tree mortality in the southern Appalachian mixed-Quercus species forest, Clinton et al [45] found scarlet oak (Q. coccinea) to be the most frequently dead or declining species, in agreement with previous reports showing a primary link to drought-induced outbreak of Armillaria mellea. The analysis of the oak decline which occurred in France following the severe 1976 drought showed that only Quercus robur was affected [14]. This could be explained by a higher sensitivity of Q. robur than Q. petraea to water deficits and a higher susceptibility to root pathogens [109,161,205].…”

Section: Species-specific and Genetic Effectsmentioning

confidence: 97%

Interactive effects of drought and pathogens in forest trees

et al. 2006

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-This review synthesizes the available knowledge on drought-disease interactions in forest trees with a focus on (1) evidence and patterns of drought-disease interactions, (2) current understanding of processes and mechanisms, and (3) three well documented cases studies. The first part is based on the analysis of a database of slightly more than one hundred studies, obtained by keyword searches combining drought, diseases or pathogens, and forest trees. A large majority of published studies referred to a positive association between drought and disease, i.e. disease favoured by drought or drought and disease acting synergistically on tree health status, with a predominance of canker/dieback diseases, caused by pathogens like Botryosphaeria, Sphaeropsis, Cytospora and Biscognauxia (Hypoxylon). The type of disease-related variables (incidence vs. severity) and the intensity and timing of water stress were shown to be significant factors affecting the drought-infection interaction. Interactions with other abiotic stresses and species-specific and genetic effects, related to host or pathogen, have also been reported. Direct effects of drought on pathogens are generally negative, although most fungal pathogens exhibit an important plasticity and can grow at water potentials well below the minimum for growth of their host plants. Studies on indirect effects of drought on pathogens through other community interactions are still relatively scarce. Positive drought-infection effects can mostly be explained by indirect effects of drought on host physiology. The predisposition and the multiple stress hypotheses are presented, as well as recent developments in the study of the molecular basis of abiotic and biotic stress, and their interactions. Sphaeropsis sapinea on pines, Biscognauxia mediterranea on oaks and root pathogens in declines associated with drought provide illustrative examples, treated as case studies, of pathogens of current significance associated with drought. The conclusion highlights some knowledge gaps, e.g. the role of latent parasites and the shift to a pathogenic stage, or the genetics of some fungal groups. The need for prevention of pathogen dispersal, especially crucial in the case of latent pathogens, is emphasized. drought / water stress / pathogenic fungi / predisposition / forest trees Résumé -Interactions entre sécheresse et agents pathogènes chez les arbres forestiers. Cette revue synthétise les connaissances actuelles sur les interactions entre sécheresse et maladies chez les arbres forestiers, avec trois grandes parties : (1) description des types d'interaction ; (2) connaissances acquises sur les mécanismes impliqués ; (3) trois études de cas bien étudiées. La première partie est basée sur l'analyse d'une base de données d'une centaine d'études, sélectionnées par recherche sur mots clés. La plupart de ces études se rapportent à des maladies favorisées par la sécheresse ou à un effet synergique entre sécheresse et maladie sur l'état sanitaire des arbres, avec une prédominance de m...

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Section: Species-specific and Genetic Effectsmentioning

confidence: 97%

Interactive effects of drought and pathogens in forest trees

et al. 2006

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“…The implication of drought in oak stand decline was demonstrated in France (after the 1976' drought [13], after the 1989-1991 dry sequence [20]), in Poland [130], and in all Central Europe wide [142]. Nevertheless, the latter authors proposed a conceptual model of the interaction of abiotic (drought) and biotic factors (defoliation for two consecutive years) responsible for the onset of oak decline.…”

Section: Drought Induced Mortalitymentioning

confidence: 99%

Temperate forest trees and stands under severe drought: a review of ecophysiological responses, adaptation processes and long-term consequences

et al. 2006

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-The extreme drought event that occurred in Western Europe during 2003 highlighted the need to understand the key processes that may allow trees and stands to overcome such severe water shortages. We therefore reviewed the current knowledge available about such processes. First, impact of drought on exchanges at soil-root and canopy-atmosphere interfaces are presented and illustrated with examples from water and CO 2 flux measurements. The decline in transpiration and water uptake and in net carbon assimilation due to stomatal closure has been quantified and modelled. The resulting models were used to compute water balance at stand level basing on the 2003 climate in nine European forest sites from the CARBOEUROPE network. Estimates of soil water deficit were produced and provided a quantitative index of soil water shortage and therefore of the intensity of drought stress experienced by trees during summer 2003. In a second section, we review the irreversible damage that could be imposed on water transfer within trees and particularly within xylem. A special attention was paid to the inter-specific variability of these properties among a wide range of tree species. The inter-specific diversity of hydraulic and stomatal responses to soil water deficit is also discussed as it might reflect a large diversity in traits potentially related to drought tolerance. Finally, tree decline and mortality due to recurrent or extreme drought events are discussed on the basis of a literature review and recent decline studies. The potential involvement of hydraulic dysfunctions or of deficits in carbon storage as causes for the observed long term (several years) decline of tree growth and development and for the onset of tree dieback is discussed. As an example, the starch content in stem tissues recorded at the end of the 2003's summer was used to predict crown conditions of oak trees during the following spring: low starch contents were correlated with large twig and branch decline in the crown of trees. drought / water balance / time lag effect / hydraulic properties / dieback Résumé -Arbres et peuplements forestiers tempérés soumis à sécheresse : une revue des réponses écophysiologiques, des processus d'adaptation et des conséquences à long terme. La sécheresse exceptionnelle de 2003 a été l'occasion de faire le point de nos connaissances sur les mécanismes écophysiologiques permettant aux arbres de traverser un tel évènement climatique extrême. L'analyse a été conduite à l'échelle de l'arbre et du peuplement, tandis que l'intensité de la sécheresse a été quantifiée à l'aide d'un calcul de bilan hydrique sur neuf sites forestiers européens contrastés du réseau CARBOEUROPE. Le rôle du couvert dans les échanges avec l'atmosphère est rappelé puis intégré dans l'analyse des réductions de bilan d'eau et de carbone en 2003 dus à la régulation stomatique. Les caractéristiques du complexe sol-racine, important à la fois pour l'accès à la ressource et à l'efficience de son absorption, constituent un des premiers traits d'ada...

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“…Preliminary observations showed that, in mixed stands, only one species, Quercus robur, was declining (Becker and Lévy, 1982) whereas the closely related species Q petraea was more drought-resistant. Another related species, Q pubescens, is mostly found in Southern Europe where severe drought develops every summer.…”

Section: Introductionmentioning

confidence: 99%

Vulnerability to air embolism of three European oak species (Quercus petraea (Matt) Liebl, Q pubescens Willd, Q robur L)

et al. 1992

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Summary — The vulnerability to water-stress induced cavitation and the petiole leaf specific conductivity (LSC) have been studied on excised branches of Quercus petraea, Q pubescens, Q robur and Q rubra. Seasonal evolution of xylem embolism in the petioles and twigs of mature Q petraea has been followed together with increasing soil water deficit. Field experiments showed that Q petraea suffered from embolism damage in both petioles and twigs after heavy drought. Large differences in terms of vulnerability to cavitation and LSC have been found between species. Q pubescens presented the highest LSC and the lowest vulnerability together with Q petraea. Q robur was found to be more vulnerable than Q petraea although with comparable LSC. Q rubra was the most vulnerable species and exhibited the lowest LSC. It was concluded that these species could be classified according to how their hydraulic mechanism is conceived to resist cavitation events : Q pubescens was the most resistant followed in order by Q petraea, Q robur, and Q rubra. Results are discussed in terms of plant segmentation and drought resistance.

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Le dépérissement du chêne en forêt de Tronçais Les causes écologiques

Cited by 49 publications

References 0 publications

Interactive effects of drought and pathogens in forest trees

Interactive effects of drought and pathogens in forest trees

Temperate forest trees and stands under severe drought: a review of ecophysiological responses, adaptation processes and long-term consequences

Vulnerability to air embolism of three European oak species (Quercus petraea (Matt) Liebl, Q pubescens Willd, Q robur L)

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