Dissertations / Theses on the topic 'Chêne sessile (Quercus petraea)'
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Bodenes, Catherine. "Différenciation moléculaire entre chêne sessile Quercus petraea (Matt) Liebl. Et chêne pédonculé Quercus robur L." Bordeaux 1, 1996. http://www.theses.fr/1996BOR10600.
Folzer, Hélène. "Approche moléculaire des réponses à l'ennoyage chez le chêne sessile (quercus petraea L. )." Besançon, 2005. http://www.theses.fr/2005BESA2044.
Moreau, Fabienne. "Recherche de marqueurs appliquée à la différenciation moléculaire entre chêne sessile (quercus petraea) et chêne pédoncule (quercus robur)." Poitiers, 1993. http://www.theses.fr/1993POIT2275.
Streiff, Réjane. "Structure génétique spatiale et flux pollinique dans une chênaie mixte : "Quercus petraea (Matt.) Liebl.", "Quercus robur L."." Montpellier 2, 1998. http://www.theses.fr/1998MON20094.
Doussot, Franck. "Variabilité des teneurs en extractibles des chênes sessile (Quercus petraea Liebl. ) et pédonculé (Quercus robur L. ) : influence sur l'élevage des vins en barrique." Bordeaux 1, 2000. http://www.theses.fr/2000BOR12308.
Morisset, Jean-baptiste. "Tomographie à rayons X; analyse et modélisation de l'ontogénèse des épicormiques du chêne sessile (Quercus petraea (L.) Matt.)." Thesis, Paris, AgroParisTech, 2012. http://www.theses.fr/2012AGPT0074/document.
Sessile oak (Quercus petraea) is a major tree species of the French forestry. Its branching, i.e. the phenomenon of twigs implementation, has a unique origin: the proventitious axillary buds set during the annual shoot (AS) elongation. We distinguish the sequential branching and the epicormic branching. Epicormic ontogeny, i.e. transition from a bud to a more complex epicormic twig as an epicormic shoot, a picot or a burl is still little known. The mark left by these twigs in the wood, the rameal trace, can depreciate its commercial value. The study of the epicormic twigs ontogeny is possible with a longitudinal follow-up or a retrospective analysis of an AS, or a dissection of the tree and an observation of the rameal traces. To free ourselves from these tedious methodologies, we used RX computed tomography which allows an exhaustive survey of all the rameal traces of a log, their ontogeny as well as the 3D reconstruction of the log. This PhD allowed to show the important effect of the tree which confers on each one its capacity to set up and maintain epicormics. The more numerous the epicormics were at young stage, the more numerous the epicormics are several years later. This trend is modulated by the actual forest operations, as the maintaining of an accompanying vegetation which play on water and carbohydrates reserve; and by past forest operation as epicormic shoot emission favoured by strong thinning. Nevertheless, the early selection of the crop trees with the few epicormic formations is a silvicultural advice of first importance in order to produce more timber wood of the best quality. A strategy of inclusion of these results in the growth simulator “Fagacées” is proposed
Alberto, Florian. "Différenciation phénologique et moléculaire du chêne sessile le long de gradients environnementaux." Thesis, Bordeaux 1, 2010. http://www.theses.fr/2010BOR14015/document.
In order to assess the capacity of sessile oak (Quercus petraea Matt. Liebl.) to withstand the ongoing climate changes, we estimated its adaptative potential for bud burst within natural populations. These populations are located along two steep temperature gradients: an altitudinal gradient comprising 12 populations located between 131 m 1630 m, and a latitudinal gradient including 21 populations from the species’ distribution range. First the demographic imprint on the overall genetic diversity was assessed on the altitudinal gradient populations using neutral markers. Results showed that genetic diversity was homogeneously distributed along the gradient and maintained at high altitudes. The genetic variability of bud burst was measured in provenance tests for 10 populations of the altitudinal gradient. We found a high level of genetic differentiation and a high heritability for the trait. A high variability was also observed within populations, indicating that selection pressures may fluctuate in natural conditions. Genetic diversity of candidate genes for bud burst was assessed on populations from both gradients. A high level of nucleotide diversity was observed, and linkage disequilibrium was low. Selective signatures were observed on few candidate genes. An association mapping study was performed between bud burst variability and polymorphism at the candidate genes on populations of both gradients separately. A total of 16 associations involving 10 genes were observed. These results suggest an important adaptive potential of sessile oak for bud burst in the face of climate change and provide interesting perspectives for the comprehension of evolutionary processes controlling bud burst adaptation of sessile oak
Parent, Claire. "Étude de la réponse à l'ennoyage chez le chêne sessile (Quercus petraea) et le chêne pédonculé (Quercus robur): Implication de l'hémoglobine non-symbiotique." Phd thesis, Université de Franche-Comté, 2008. http://tel.archives-ouvertes.fr/tel-00367796.
Lagache, Lélia. "Hybridation et dynamique de la spéciation chez les chênes sessile (Quercus petraea) et pédonculé (Quercus robur)." Thesis, Bordeaux 1, 2012. http://www.theses.fr/2012BOR14704/document.
Quercus petraea and Q. robur are two interfertile sympatric species. They occupy distinct stages during forest succession and constitute therefore good models for ecological speciation studies. Despite their differences, they often grow together in mixed stands, allowing the study of their intra- and interspecific reproductive system. Hybridization between these two oak species has been suggested to be frequency-dependent. The effect of the relative species abundance on hybridization is known as the “Hubbs’ effect”, from the name of an ichthyologist who described this mechanism in 1955. My work was to study the processes that limit hybridization between these two species, thereby allowing their coexistence. I conducted an extensive paternity analysis (almost 3500 individuals genotyped at 12 microsatellite markers). First, I tried to delimitate the two oak species by applying for the first time in situ the interfertility criterion. Then, I focused on interspecific crosses by studying those factors influencing hybridization. Results showed that the maintenance of these two species depends on the frequency of each species and their distribution, as both factors influence the quantity of pollen received by female flowers. Thanks to this empirical study and to this modeling approach, we have now a much better view of environmental effects on hybridization. I then compared the characteristics of the reproductive system of each species (pollen dispersal and male fertility) in relation with their ecological strategies. The results suggest that differences in species ecological dynamics are at the origin of the speciation process but that at a finer scale the stability of the environment is crucial for species’ maintenance
Bréda, Nathalie. "Analyse du fonctionnement hydrique des chênes sessile (Quercus petraea) et pédonculé (Quercus robur) en conditions naturelles : effets des facteurs du milieu et de l'éclaircie." Nancy 1, 1994. http://docnum.univ-lorraine.fr/public/SCD_T_1994_0024_BREDA.pdf.
Saintagne, Caroline. "Distribution des régions génomiques différenciant deux espèces proches : le chêne sessile (Quercus petraea) et le chêne pédonculé (Q. robur)." Nancy 1, 2003. http://docnum.univ-lorraine.fr/public/SCD_T_2003_0059_SAINTAGNE.pdf.
Sessile (Quercus petraea) and pedunculate (Q. Robur) oak which are two inter-fertile species colonising the same space, display similar genomes, whereas maintain ecological and morphological specific differences. Two complementary approaches have been applied to study the molecular origin of phenotypic differences: (i) Location of QTL, controlling characters which differentiate the two species, in a genetic linkage map of pedunculate oak; (ii) estimation, in natural mixt stand, of the inter-specific differentiation coefficient (GST) for different types of molecular markers, already mapped in the same map. The both approaches suggests that genome regions involved in inter-specific differentiation are dispersed across the genome, although with a tendency to within-linkage group clustering in small distance. Our results suggest that species differentiation is mainly due multi-locus effects maintained by selective pressure strong enough to prevent gene flow from disrupting them
Trencia, Jacques. "Sylviculture et production du chêne sessile en France." Nancy 1, 1989. http://www.theses.fr/1989NAN10486.
Gérard, Bastien. "Recherche de marqueurs physiologiques de tolérance à l'ennoyage chez le chêne pédonculé (Quercus robur L.) et chez le chêne sessile (Quercus petraea [Matt] Liebl.)." Phd thesis, Université de Franche-Comté, 2008. http://tel.archives-ouvertes.fr/tel-00725019.
Abadie, Pierre. "Génétique et évolution de l'isolement reproducteur entre chêne sessile (Quercus petraea (Matt.) Liebl.) et pédonculé (Q. robur L.)." Thesis, Bordeaux 1, 2011. http://www.theses.fr/2011BOR15270/document.
Speciation can be defined as the range of processes that lead to the evolution of reproductive isolation among groups of individuals. Past decades have witnessed a renewal in the recognition of natural selection as a primary force in the formation of new species, in particular for ecological speciation models in conditions of sympatry. Sessile oak (Quercus petraea (Matt.) Liebl.) and pedunculate oak (Q. robur L.) are two sympatric species which exhibit large morphological and ecological differences, despite relatively high estimated rates of natural hybridization. However, very little is known about the nature and strength of reproductive barriers between those two species. The objective of this thesis was therefore to characterize their isolating barriers at phenotypic and genetic levels, in order to better understand their relative importance, their role in the process of divergence and their evolution in that species complex. A first approach based on controlled crosses has shown (i) the existence of strong barriers at the pre-zygotic level and that of significant although weaker ones at the post-zygotic level, based on observations from fitness of hybrid progenies, and (ii) a large variability for traits linked to barriers phenotypes, across genotypes and also for their expression in different micro-environments. A second approach of population genomics used 33 candidate genes to reproductive isolation and allowed to identify «speciation genes» submitted to divergent selection, the strongest divergence being observed for genes involved in the flowering pathway. The model of colonization of these oak species in natural stands was discussed in the light of these new results
Morisset, Jean-Baptiste. "Tomographie à rayons X; analyse et modélisation de l'ontogénèse des épicormiques du chêne sessile (Quercus petraea (L.) Matt.)." Phd thesis, AgroParisTech, 2012. http://pastel.archives-ouvertes.fr/pastel-00908159.
El, Zein Rana. "Dynamiques saisonnières des réserves carbonées et azotées chez le chêne sessile (Quercus petraea) et le hêtre (Fagus sylvatica) adultes." Thesis, Nancy 1, 2011. http://www.theses.fr/2011NAN10002/document.
Sessile oak and beech are two deciduous temperate broadleaved species, characterized by contrasted foliar and cambial phenologies. In order to progress in our understanding of reserves management in these species, we studied the seasonal dynamics of carbon (C) and nitrogen (N) reserves in adult trees in their natural environment. For this purpose, we developed a multidisciplinary approach associating ecophysiology, biochemistry and isotopy. The monthly monitoring of seasonal variation in C and N reserves in the stem sapwood showed a strong remobilization of starch from the most recent rings of oak in the spring in order to supply the necessary C for early wood growth that is concomitant to leaf expansion in this species. For beech, spring growth seemed to be less dependant on C stored within the stem sapwood. In both species, 2 polypeptides of 13 and 26 kDa accumulated with leaf senescence in the autumn and were highly abundant during the dormant period then they were remobilized with bud burst in the spring. This seasonal variation supports their role in nitrogen storage as vegetative storage proteins (VSP) and does not exclude a role in cold hardiness too. In sessile oak, the in situ 15N labeling of soil N (newly absorbed N) during the bud burst in the spring showed that N reserves accounted for 90% of total N of the new organs (leaves and twigs) at the first stages of growth. The contribution of newly assimilated N became more important when bud burst was achieved. The distribution patterns of non-structural C and N concentrations and amounts at the tree level was realized by an exhaustive sampling of trees from both species in the winter (January) and at full leaf expansion (June). This study showed i) that the distribution of concentrations among tree organs was dependant of the physiological function, wood anatomy and proximity to sink organs, ii) the importance of stem sapwood and coarse roots in reserves storage during the winter, iii) the importance of non-structural nitrogen amounts in leaves and twigs despite their low biomass, iv) higher amounts of non-structural C and N compounds in oak compared to beech, that reflects contrasted needs for spring growth and tissue maintenance during the winter dormancy
Masson, Eric. "Incidence du mode de séchage sur les caractéristiques physico-chimiques du bois de chêne de tonnellerie (Quercus petraea (Matt. ) Liebl. )." Nancy 1, 1999. http://www.theses.fr/1999NAN10302.
Bakker, Mark. "Effet des amendements calciques sur les racines fines de chêne (Quercus petraea et robur) : conséquences des changements dans la rhizosphère." Nancy 1, 1998. http://docnum.univ-lorraine.fr/public/SCD_T_1998_0276_BAKKER.pdf.
Parelle, Julien. "Réponses de jeunes chênes de deux espèces (Quercus robur L. , Q. Petraea [Matt] Liebl. ) à l'hypoxie racinaire : Marqueurs physiologiques, moléculaires et génétiques de sensibilité et application à la comparaison des deux espèces." Nancy 1, 2006. http://www.theses.fr/2006NAN10049.
Pedonculate oak (Q. Robur) and sessile oak (Q. Petraea) differ by their ecological requirements. In particular Q. Robur displays a larger tolerance to water-logging than Q. Petraea. Inter-specific differences were found in the response to water-logging at root metabolism level, with differences in pyruvate decarboxylase (transcripts and activity), key enzyme in the alcoholic fermentation pathway. Moreover, the long term maintenance of the enzymes of sucrose catabolism, should underline a lower carbon unloading in hypoxic roots of Q. Petraea than in Q. Robur. The larger capacity of Q. Robur to produce adventitious roots and hypertrophied lenticels was confirmed. These organs were shown to be related to the degree of water-logging tolerance of the species, despite they do not seem to be involved in root aeration. In addition, the degree of leaf epinasty was demonstrated to be an early symptom of plant sensitivity to the stress. QTL were identified for hypertrophied lenticels formation and for the degree of epinasty in Q. Robur. The use of a multi-environment model allowed to record the temporal evolution of the allelic substitution effect of some of the QTL detected, and evidenced that the response to water-logging probably involves a large number of genes induced simultaneously over the whole genome. The intra-specific variability of response to water-logging suggests that the higher tolerance of Q. Robur would be due to an higher variability resulting in an higher frequency of tolerant seedlings, compared to Q. Petraea, in spite of a common genetic background for the two species, and not to different specific traits
Picon-Cochard, Catherine. "Effets combinés d'un doublement de la concentration en C02 de l'air et de sécheresses édaphiques sur la croissance et l'efficience d'utilisation de l'eau de Quercus petraea, Quercus robur et Pinus pinaster." Nancy 1, 1996. http://www.theses.fr/1996NAN10076.
Valenzuela, Nunez Luis Manuel. "Comparaison interspécifique de la dynamique saisonnière de composés azotés et carbonés chez le chêne sessile (Quercus petraea Matt. Liebl. ), le chêne pédonculé (Quercus robur L. ) et le hêtre (Fagus sylvatica L. ) aux stades juvéniles et adultes : effet de la défoliation et de la lumière sur la gestion des réserves." Nancy 1, 2006. http://docnum.univ-lorraine.fr/public/SCD_T_2006_0177_VALENZUELA-NUNEZ.pdf.
This research allows us to compare the biomass composition in nitrogenous and carbon compounds in three forest tree species. C contents (g / kg biomass) are stable whatever the species and age. N contents (g / kg biomass) are 10 times more in young trees, whatever the species. It has important links between N content and age. The C/N ratio is almost 10 times less in young trees, due to their content of total nitrogen. Stocks for a given age are comparable between species. Starch contributes to total carbon in a more important fraction in young trees: 50 % against 8 % in adult trees. Starch concentration in Quercus robur is more elevated in comparison with Quercus petraea and Fagus sylvatica. This comparison of species, in both youth and adult ages, allowed the evidence of different physiological mechanisms, linked to phenology. This research concerned the characterization of carbon and nitrogenous reserves by difference of present quantities at tree level in two dates corresponding to important phenologic stages. We used the 15N labelling, which allowed partitioning of nitrogen neo-assimilated to nitrogen coming from reserves remobilisation, in young trees defoliated and in different light conditions. Carbon and nitrogen remobilisation of reserves seems to be not synchronous and differed among species: oak renew only 10% of its nitrogen while beech renew 20%. We have characterized a 25kDa polypeptide in the trunk sapwood of Quercus robur, this polypeptide presents all characteristics of a Vegetative Storage Protein (VSP). Limits and uncertainties of methods used during this research are discussed
Wagner, Pierre-André. "Écophysiologie comparée de plants de chêne pédonculé (Quercus robur L. ) et de chêne sessile (Quercus petraea (Matt. ) Liebl. ) soumis à deux contraintes racinaires successives : hypoxie et sécheresse : application à la mise en valeur forestière des pélosol-pseudogleys." Nancy 1, 1996. http://docnum.univ-lorraine.fr/public/SCD_T_1996_0354_WAGNER.pdf.
Barbaroux, Cécile. "Analyse et modélisation des flux de carbone de peuplements forestiers pour la compréhension de la croissance de deux espèces feuillues Quercus petraea et Fagus sylvatica." Paris 11, 2002. http://www.theses.fr/2002PA112084.
Several dendroecological studies (inter-annual variations of the tree-rings width according to the climate) of the sessile oak (ring porous species) and of the beech (diffuse porous species) put into evidence their interrelationships with the climatic signal of the year and differed effects of the climate or the growth. These differed effects are often more obvious and older on oaks. Our objectives are to verify if the anatomies and/or the contrasted phenology (setting up of leaves, resuming of wood growth) of these two species entail a different management of carbohydrate reserves, and of specific carbon allocation pattern, at intra- and in inter-annual scales. To reach these objectives, we have developed a pluridisciplinary approach associating dendrochronology, ecophysiology, dendrometry and modeling of water and carbon functioning of oaks and beeches stands. The analysis of the inter-annual variations of radial growth of the oak and of the beech was based on the last 30 years measurements on 900 varied trees in terms of fertility and age in the Fontainebleau forest. Dendroclimatic study puts into evidence a strong dependence of the beeches stands productivity on the soil water availability during the season of vegetation of the year and the previous year. For oaks stands, the productivity is correlated to the soil water availability during the season of vegetation and to the growth of the previous year. The biochemical analysis of carbohydrate reserves (starch, sucrose, glucose and fructose), made on two pure stands of oaks and beeches of 35 years old in Lorraine, reveals a seasonal dynamics of reserves more obvious as well as an higher concentration for the oak. These differences of reserve management correspond to the important needs in growth of the oak during the phase of carbon heterotrophy. Analyzing the reserves quantities and yearly growth in biomass of the population on several years required preliminary works to describe intra- and inter-trees variability and then to up-scale the studied tree to the stand. Knowledge acquired on the seasonal dynamics of carbohydrate reserves quantities, as well as on the growth phenology of the oak and the beech, have been integrated in a model of stand carbon balance (CASTANEA, E. Dufrêne). The possible changes of carbon allocation to the growth between years can be tested thanks to the model, through hypotheses of interactions between dynamics appropriate in reserves and growth. These modifications have been tested on the Fontainebleau site. .
Ponton, Stéphane. "Analyse de l'efficience d'utilisation de l'eau des chênes pédonculé (Quercus robur L. ) et sessile (Quercus petraea (Matt. ) Liebl. ) : relation avec les dépérissements des chênaies." Nancy 1, 2002. http://docnum.univ-lorraine.fr/public/SCD_T_2002_0184_PONTON.pdf.
The two sympatric European oak species Quercus robur and Q. Petraea display distinct ecological requirements and drought sensitivities. Intrinsic water-use efficiency (WUEint) was studied on the basis of both measurements of instantaneous gas exchange and carbon isotopic composition of plant tissue (d13C). Retrospective analysis of d13C in wood cellulose of adult trees from the two species growing in mixed stands showed a time-stable interspecific difference. Gas exchange measurements performed on 2-year old seedlings grown in "common garden" confirmed the higher WUEint of Q. Petraea than Q. Robur, mainly due to stomatal conductance variations between the two species. A genetic basis to these interspecific differences was suggested. The results provided new insights in the understanding of the ecology of these species. However, no clear relationships were observed between tree-ring growth or d13C and sensitivity to drought-induced decline. The relationship between WUEint and drought resistance is discussed
Bontemps, Jean-Daniel. "Evolution de la productivité des peuplements réguliers et monospécifiques de hêtre (Fagus sylvatica L. ) et de chêne sessile (Quercus petraea Liebl. ) dans la moitié Nord de la France au cours du XXe siècle." Paris, ENGREF, 2006. http://www.theses.fr/2006ENGR0007.
Historical evolution of forest productivity is investigated for the French main two social broadleaved species – common beech (Fagus sylvatica L. ) and sessile oak (Quercus petraea Liebl. ) – in pure even-aged stands from State forests, with an aim of description and quantification at stand scale. The analysis therefore focuses on dominant height growth, a classical proxy for forest productivity. Using a retrospective approach (stem analysis), increments were sampled from two generations of stands associated in couples to ensure control of site conditions. The evolution of growth rate is estimated by statistical modelling of increments, accounting for the effect of stand developmental stage and site differences between couples. Growth trends were assessed at a regional scale, leading to the constitution of 2 samples for beech (Normandie/Picardie, Lorraine/Alsace) and 4 samples for oak (Normandie, val de Loire, plaine d’Allier, Lorraine/Alsace). The increase in dominant height growth rate is widespread on the territory, although its intensity varies along a longitudinal gradient. Whereas it appears to be more pronounced in the Northeastern area for both species, it remains weak or recent in the Northwestern area. Most of the evolution formed in the second half of the century. The secular increase in dominant height growth rate varies between +20% and +100% in extreme situations and reaches an approximate +50-60% common to both species in Northeastern France when eluding the effect of recent years. A multi-causal determinism is suggested. Faster growth rate evolution in recent decades, together with its organisation in space and the sensitivity of species to trophic conditions, emphasize the possible key role of atmospheric nitrogen deposition in the response to environmental changes
Guilley, Edith. "La densité du bois de chêne sessile (Quercus petraea Liebl.) : Elaboration d'un modèle pour l'analyse des variabilités intra- et inter-arbre; Origine et évaluation non destructive de l'effet « arbre »; Interprétation anatomique du modèle proposé." Phd thesis, ENGREF (AgroParisTech), 2000. http://pastel.archives-ouvertes.fr/pastel-00002809.
Gilson, Angelique. "Dynamique saisonnière et répartition du Carbone et de l’Azote : de l’organe au peuplement. Rôle des réserves et effets de l’âge chez le chêne sessile (Quercus petraea)." Thesis, Paris 11, 2015. http://www.theses.fr/2015PA112038/document.
In order to progress in the comprehension of tree carbon and nitrogen functioning, this work studies tree age effects on seasonal changes and quantities of carbon and nitrogen reserves.This study was performed in situ in a chronosequence of three different ages of sessile oaks (8, 20 and 150 years old). Seasonal dynamics of carbon and nitrogen compound concentrations was studied for one year in young branches and fine and medium roots, at key phenological and growth stages. The reserve quantification was possible thanks to the estimation of the living biomass of the tree different organs. The study of age effects on carbon and nitrogen reserve quantities and their distribution within the tree biomass was realized at the dominant tree scale and the stand scale.Seasonal dynamics of carbon reserve formation changes with ageing. Young trees allocate preferentially C to growth; C storage begins only after the end of wood growth. In mature trees, growth and storage occur at the same time during the vegetative period. Seasonal dynamics of nitrogen reserves is overall not different between the three age classes: the minimum nitrogen reserve is observed in summer and the maximum one after yellowing. Mature trees have higher amino acid concentrations, which could be explained by a higher fine root biomass and a higher mycorrhization rate at mature stage, allowing a better soil exploration and mineral nutrient.Carbon and nitrogen reserve quantities of the dominant tree and stand increase within age. Reserve distribution mainly depends on the living biomass distribution between the different organs. Stem stocks the majority of tree and stand carbon and nitrogen reserves for the three age classes. However carbon and nitrogen compound concentrations have an important effect on the reserve localization in tree because carbon and nitrogen reserve distribution can be different from the living biomass one. With this study, we show that carbon compound allocation to storage in coarse roots and branches increase progressively with tree age.The results of this study highlight an evolution in C and N management with tree age
Caignard, Thomas. "Variabilité phénotypique et génétique des traits de reproduction de deux espèces de chêne blanc européen (Quercus petraea et Q. robur)." Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0060/document.
Forest ecosystem dynamics closely depend on tree reproduction. Many studies have investigated the synchronous and non-predictable year-to-year variability of seed production, characteristic of masting species. However, little is known about the sensitivity of tree reproduction to climate variables and to which extent this phenotypic variability is genetically and/or environmentally driven. We intensively studied the reproduction of two European temperate oaks and our aims were (i) to characterize the change in reproductive traits over the last two decades, (ii) to assess the determinism of their variations along environmental gradients and (iii) to estimate the heritability of reproductive traits and identify the regions of their genome related to reproduction. We were able to show a dramatic increase in seed production over the last 14 years. This increase in seed production and size was significantly correlated with increasing spring temperatures. We then confirmed this sensitivity to temperature by studying the reproduction of oak populations growing along the elevation gradient of the Pyrenees. Based on a common garden approach, we then showed significant genetic differentiation between oak provenances and demonstrated that the genetic and phenotypic clines for the reproductive traits observed along the environmental gradient have opposite signs (counter-gradient). Contrary to growth traits, for which genetic variation parallels phenotypic variation, the counter-gradient observed for reproduction-related traits suggested that genetic variation partly counteracts the phenotypic effect of temperature, moderating the change in reproductive effort according to temperature. Finally, using a full-sib family where reproduction was monitored during four consecutive years, we found a high heritability of reproductive traits and showed high genetic differentiation between trees of a same population, which confirms the significant genetic determinism observed earlier. Furthermore, we were able to identify for the first time in forest trees quantitative trait loci (QTLs) associated with seed production and size. Our findings show that reproduction-related traits may undergo evolutionary changes under selective pressure and may be determinant for tree adaptation in response to environmental changes
Bornot, Yoran. "Peut-on changer les trajectoires de croissance du chêne sessile et du sapin de Douglas suite à une sécheresse en modulant la fertilité du sol ?" Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0356/document.
Fertilization and liming are usual practices in agronomy but uncommon in forestry. Experimental liming or fertilization in forest were tested in the 1970’s. The initial aim of these experimentations was to determine if the addition of nutrients on poor or acidic forest soil could increase tree growth or even restore crown condition in case of decline. Physiological studies have established the implication of water availability in soil nutrients uptake and their transport in the sap and also via combined effects in various processes such as cell growth or stomatal control. Recently, extreme drought events responsible of many forest species diebacks have aroused the concern of forest managers. In addition, climate models predict an increase in the frequency and intensity of drought hazards in the future and forest management must be adapted to face them. In this context, and thanks to the current knowledge on the interactions between mineral and water alimentation, we investigate whether nutrient supply could mitigate the negative effects of water deficits by increasing the capacity 1/ to withstand droughts and 2/ to recover optimum growth after the drought induced crisis, i.e. to improve the resilience of trees. Conversely, would the vulnerability of trees to water deficits be increased? To answer this question, we investigated fertilization experiments located in three forests in France and applied on two species, sessile oak and Douglas fir. On each of these sites, selected trees were cored to the pith to determine the annual variations of radial growth from measurements of the tree-rings widths. These growth variations were used as a basis to the calculation of resistance, recovery and resilience indices to drought events, which were quantified using a soil water deficit index computed by the water balance model BILJOU©. On the site of Bercé, the water-use efficiency was estimated from the δ13C of the latewood. Retrospective analyses shown that the radial growth of oak trees in Bercé and Tronçais was significantly increased after the fertilization. Radial growth was then modelled from climate and soil water deficit. Douglas fir radial growth was slightly impacted by the nutrient supply in the Potées site. This analysis highlights the time-limited effect of this nutrient supply on the growth stimulation: no effect subsists more than 10 years after nutrient supply in Bercé and more than 20 years in Tronçais. Despite this transient effect on oak growth, no differences between treatments on the capacity of trees to resist and to recover after drought events was observed. The main factors influencing resistance and recovery of growth were the soil water deficit intensity and duration. These results corroborate δ13C analyzes in oak rings, which, again, were only significantly correlated with climate and were independent of treatment. The lack of modification of the resilience between the treatments, whatever the site and the species studied, is discussed. More broadly, the concept of resilience and its use in dendroecology are questioned
Fernandez, Marine. "Mécanismes écophysiologiques impliqués dans les interactions antagonistes entre le jeune chêne sessile (quercus petraea (Matt.) Liebl.) et la molinie bleue (Molinia caerulea (Moench) L.) : rôles des transferts d'azote, des mycorhizes et des rhizodépôts allélochimiques." Thesis, Université Clermont Auvergne (2017-2020), 2019. http://www.theses.fr/2019CLFAC053.
A better understanding of plant interactions would improve the management of natural and artificial forest regeneration. It is well established that Molinia (Molinia caerulea), a monopolist species of understory, has a particularly depressive effect on young sessile oak (Quercus petraea) establishment and growth. Large capacity of Molinia in water and soil nutrients uptake leads to strong competition by resources exploitation. However, it seems that other interactions are involved in the relationship between young oak and Molinia. Thus, the allelopathic properties of Molinia have been suggested, but no study has shown such an effect on oak. Inversely, young oak seems to facilitate Molinia growth. Oak-Molinia interaction thus has the singularity of being antagonistic: the Molinia inhibits oak growth while this one favors grass growth, but the mechanisms involved are not entirely known. The aim of this thesis was to analyze the functional and ecophysiological mechanisms involved in the interactions between young sessile oak and Molinia. The experiments carried out in the thesis show that (i) oak quickly transfers nitrogen to Molinia by the underground pathways (rhizodeposition of nitrogen compounds in the soil) favoring grass growth, (ii) Molinia presence in the same pot leads to a decrease in the lateral root rate and ectomycorhization rate of oak and (iii) Molinia rhizodeposes secondary metabolites different from those of oak and have an allelopathic potential. In line with current work, the thesis puts into perspective that the chemical compounds emitted by plants in the soil act as real direct or indirect signals (via the biological communities of the soil) and induce neighbors modifications in their metabolism and / or their growth
Gerardin, Théo. "Plasticité et diversité de l’efficience d’utilisation de l’eau chez deux espèces de chêne blanc d’Europe : les chênes pédonculé (Quercus robur L.) et sessile (Quercus petraea (Matt.) Liebl.) : approche descriptive de la dynamique de réponse stomatique aux changements environnementaux." Thesis, Université de Lorraine, 2019. http://www.theses.fr/2019LORR0120/document.
Quercus robur L. and Quercus petraea (Matt.) Liebl. are two sympatric oak species occupying distinctive ecological niches as well as presenting disparate drought tolerances. Available litterature reports the existence of stable inter-specific differences of water use efficiency (WUE) between the two species, Q. petraea displaying higher values than Q. robur. Water use efficiency can be studied at several integration scales both spatially and temporally. Based on instantaneous foliar gaz exchange, the intrinsic water use efficiency can be determined (Wi). On the other hand, water use can be characterised by measurements of the carbon isotopic composition of plant tissues (13C) or by estimation of the whole plant transpiration efficiency (TE), thus allowing a time-integrated estimate of water use. The characterisation of WUE through these different estimators allowed us to put in evidence in oak seedlings grown under controlled conditions a higher transpiration efficiency in Q. robur even though no differences were observed between the two species regarding instantaneous measurements (Wi). TE variations were mainly linked to the variations of the biomass production by the plants while Wi variations were essentially associated to the stomatal conductance. Both intra and inter specific variations of the dynamics of stomatal response to step changes of environmental factors (light, CO2, VPD) could not be clearly linked to the variations of the different WUE estimates nor their respective components. Nevertheless, drought conditions impacted the stomatal dynamics in both species towards faster stomatal responses, especially for stomatal closing. Furthermore, the main observed differences between species were linked to biomass production. Both species displayed different carbon allocation strategies, especially regarding the root compartment. Thus, Q. petraea produced a significantly more ramified and thinner root system than Q. robur. Such behaviour was accentuated under drought stress, under which Q. robur was more sensitive than Q. petraea in term of biomass production. The complexity of the relationships between water use efficiency and all of these morphological and physiological traits as well as the possible drought tolerance implications in both oak species are discussed in this PhD thesis
Gerardin, Théo. "Plasticité et diversité de l’efficience d’utilisation de l’eau chez deux espèces de chêne blanc d’Europe : les chênes pédonculé (Quercus robur L.) et sessile (Quercus petraea (Matt.) Liebl.) : approche descriptive de la dynamique de réponse stomatique aux changements environnementaux." Electronic Thesis or Diss., Université de Lorraine, 2019. http://www.theses.fr/2019LORR0120.
Quercus robur L. and Quercus petraea (Matt.) Liebl. are two sympatric oak species occupying distinctive ecological niches as well as presenting disparate drought tolerances. Available litterature reports the existence of stable inter-specific differences of water use efficiency (WUE) between the two species, Q. petraea displaying higher values than Q. robur. Water use efficiency can be studied at several integration scales both spatially and temporally. Based on instantaneous foliar gaz exchange, the intrinsic water use efficiency can be determined (Wi). On the other hand, water use can be characterised by measurements of the carbon isotopic composition of plant tissues (13C) or by estimation of the whole plant transpiration efficiency (TE), thus allowing a time-integrated estimate of water use. The characterisation of WUE through these different estimators allowed us to put in evidence in oak seedlings grown under controlled conditions a higher transpiration efficiency in Q. robur even though no differences were observed between the two species regarding instantaneous measurements (Wi). TE variations were mainly linked to the variations of the biomass production by the plants while Wi variations were essentially associated to the stomatal conductance. Both intra and inter specific variations of the dynamics of stomatal response to step changes of environmental factors (light, CO2, VPD) could not be clearly linked to the variations of the different WUE estimates nor their respective components. Nevertheless, drought conditions impacted the stomatal dynamics in both species towards faster stomatal responses, especially for stomatal closing. Furthermore, the main observed differences between species were linked to biomass production. Both species displayed different carbon allocation strategies, especially regarding the root compartment. Thus, Q. petraea produced a significantly more ramified and thinner root system than Q. robur. Such behaviour was accentuated under drought stress, under which Q. robur was more sensitive than Q. petraea in term of biomass production. The complexity of the relationships between water use efficiency and all of these morphological and physiological traits as well as the possible drought tolerance implications in both oak species are discussed in this PhD thesis
FONTAINE, FLORENCE. "Les bourgeons epicormiques chez le chene sessile (quercus petraea matt. Liebl. ) : etablissement des bases en vue d'une evaluation dynamique d'un potentiel epicormique." Reims, 1999. http://www.theses.fr/1999REIMS020.
Coq--Etchegaray, Domitille. "Déterminisme génétique de la variation des métabolites spécialisés en lien avec les interactions biotiques chez une plante de grande culture et une espèce forestière dominante." Electronic Thesis or Diss., Bordeaux, 2023. http://www.theses.fr/2023BORD0478.
Chemical compounds also called “specialized metabolites” play a key role in protection and defense of plants against environmental stresses. Many specialized metabolites are involved in defenses against herbivores or contribute to resistance to oxidative stresses. Within species, specialized metabolites production varied extensively between individuals. This variation may be a response of individuals to biotic and abiotic stresses, but also originated from genetic differences among individuals. Thus, specialized metabolites natural variation, whether constitutive or induced in response to the environment, is controlled by genetic differences between individuals, cultivars or populations. During my PhD, we studied the variation of specialized metabolism determined by genetic differences between individuals within two species, sessile oak (Quercus petraea) and bread wheat (Triticum aestivum). In the first chapter, we investigate the natural variation of leaf specialized metabolites and identify the genetic basis underlying the variation within sessile oak populations, a long-lived species displaying high genetic diversity among populations. While studying the natural variation and the underlying genetic basis, we explored the genetic diversity patterns associated with specialized metabolism within and among populations. We showed that a majority of specialized metabolites we investigated don’t display differentiation among populations. Interestingly, we detected genetic polymorphisms with large effects on specialized metabolites suggesting that variation of specialized metabolites within populations has a large genetic component. While studying specialized metabolites annotations and candidate genes we discuss hypotheses that may explain the maintenance of genetic diversity. In the second chapter, we explore the differentiated expression of specialized metabolism-related genes of bread wheat cultivars in response to the infection by a pathogen. Here, we study the potential role of artificial selection, as well as polyploidy, on the capacity of cultivars to induce differentiated gene expression responses of genes related to the specialized metabolism. By studying relative gene expression among copies of homoeologous genes, termed as expression bias, we explored the role of polyploidy on the gene expression response to the infection by a pathogen. Specifically, we explored whether cultivars, with different genetic backgrounds shaped through breeding programs, displayed differentiated expression bias and changes in expression bias in response to the infection. We showed that specialized metabolism homoeologous genes displayed contrasting changes of homoeolog expression biases in response to the infection among cultivars. Identifying the genetic or epigenetic variation among cultivars influencing the plastic response of expression bias improves our understanding of how the selective history of the cultivars modified how the three wheat subgenomes interact. Overall, the results of this work show that the intraspecific variation of specialized metabolite production within these two species is strongly influenced by genetics and that structural genetic variation is an important component of the genetic bases of these traits. Specifically we highlighted the importance of two types of structural variation shaping the variation of specialized metabolites production. In oaks, a diploid species with high genetic diversity, polymorphisms between duplicated genes associated with specialized metabolism appear to be a major source of functional and genetic diversity of the natural variation of specialized metabolism. On the other hand, in wheat, a highly selected species with lower genetic diversity, the relative contribution of homoeologous genes to the transcription of specialized metabolism related genes appears to be a source of variation in the induction of specialized metabolism in response to biotic stresses
Bontemps, Jean-Daniel. "Evolution de la productivité des peuplements réguliers et monospécifiques de hêtre (Fagus silvatica L.) et de chêne sessile (Quercus petraea Liebl.) dans la moitié Nord de la France au cours du XXe siècle." Phd thesis, ENGREF (AgroParisTech), 2006. http://pastel.archives-ouvertes.fr/pastel-00761239.
L'augmentation de la vitesse de croissance en hauteur dominante a un caractère général sur le territoire, structuré selon un gradient longitudinal. Pour chaque essence, elle est plus marquée dans le Nord-Est, tandis qu'elle reste faible ou récente dans le Nord-Ouest. L'essentiel de l'évolution a été acquis dans la seconde moitié du siècle. La progression est ponctuée de crises d'origine climatique, communes ou spécifiques, dont la plus marquée est celle de la décennie 1940. Défavorable au hêtre, la décennie 1990 a été bénéfique au chêne, et explique que l'évolution constatée pour cette essence culmine en fin de siècle à un niveau bien supérieur à celui du hêtre. L'augmentation séculaire est comprise pour les extrêmes entre +20% et +100%, et atteint dans le Nord-Est un niveau commun aux deux essences de +50-60% en excluant la période récente. Dans ce secteur, les évolutions de croissance radiale et en hauteur du hêtre sont similaires. La densité du bois est restée stable. En conséquence, la productivité en biomasse a pu suivre l'évolution estimée sur la hauteur dominante. L'analyse des relations croissance - facteur du milieu permet d'aborder la causalité des changements de productivité, et suggère un déterminisme multifactoriel. Le climat aurait eu jusqu'alors des conséquences essentiellement conjoncturelles. Des effets saisonniers opposés sur la croissance sont de plus possibles. Le caractère récent des évolutions constatées, leur organisation spatiale, conjugués à une sensibilité des essences aux conditions trophiques, font ressortir le rôle clé possible des dépôts atmosphériques azotés dans la réponse aux changements de l'environnement.
Vernay, Antoine. "De la complexité fonctionnelle et écophysiologique des ressources lumières, azote et eau dans le réseau précoce d'interactions entre le jeune chêne (Quercus petraea) et deux Poacées (D. cespitosa et M. caerulea) : conséquences pour la régénération des chênaies tempérées." Thesis, Université Clermont Auvergne (2017-2020), 2017. http://www.theses.fr/2017CLFAC081/document.
Temperate forest ecosystems are prone to regeneration failures because of strong competition between understorey species and tree seedlings. This thesis aimed to improve our understanding of sessile oak seedlings (Quercus petraea) and poacea responses, both in competition among different levels of resource availabilities. Two poacea species were studied, Molinia caerulea and Deschampisa cespitosa. We focused on the role of the different resource combinations (light, water and inorganic nitrogen) on interaction variation (intensity and importance) between those species and underlying ecophysiological mechanisms. Our greenhouse and field experiments allowed us to infer a very early competition, from the first months of interaction between oak seedlings and poacea neighbours. High light level leads to stronger competition from poacea on oak seedlings, increased by nitrogen supply. Secondly nature and extent of these interactions depend on applied abiotic stress level and on considered organs. Thirdly Oak seedlings mainly respond by accumulating resources in coarse roots. These resources are remobilized next year and may have a positive carry-over effect on oak functioning if there is no water stress. Eventually we observed facilitation as well, from oak on D. cespitosa in fertilized environment. Nitrogen supply would foster oak seedling growth, increasing exudate production and root turn-over, to the benefit of D . cespitosa. The poacea would take up this extra nitrogen source for its own development. This study support the idea of including interaction effects of different abiotic factors in competition models. Silvicultural practices would also be enhanced by optimizing species coexistence in temperate forests as soon as tree seedlings and understorey species start to grow together
Hatsch, Elvire. "Repartition de l'aubier et acquisition de la forme de la tige chez le chene sessile (quercus petraea (matt) liebl) : analyse, modelisation et relation avec le developpement du houppier." Paris, ENGREF, 1997. http://www.theses.fr/2000ENGR0051.
Le, Moguédec Gilles. "Modelisation de proprietes de base du bois (coefficients de gonflement et densite du bois) et de leur variabilite chez le chene sessile (quercus petraea liebl. ). Simulations en vue de l'evaluation d'une ressource forestiere." Paris, Institut national d'agronomie de Paris Grignon, 2000. http://www.theses.fr/2000INAP0011.
Trainer, Eva. "Reproduktion in Beständen der Traubeneiche (Quercus petraea (Matt.) Liebl.) Reproduction in sessile oak (Quercus petraea (Matt.) Liebl.) /." [S.l.] : [s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=96268371X.
Bresson, Caroline. "Variations altitudinales de traits fonctionnels foliaires chez les arbres : déterminismes environnemental et génétique." Thesis, Bordeaux 1, 2011. http://www.theses.fr/2011BOR14220/document.
The rapid climate change, which we are currently witnessing, is already modifying the physiology and distribution of species. Predictions of changes in species distributions do not take evolutionary mechanisms and biotic interactions into account. Our main objective was to assess the inherent adaptive capacities of tree populations by i) quantifying the phenotypic variations of functional traits with altitude and ii) studying the extent to which these variations are environmentally driven (phenotypic plasticity) and/or genetically fixed (adaptation). The study took place in the French Pyrenees along an altitudinal gradient range of 1500 m corresponding on average to 8°C of thermal amplitude. We focused on two broadleaved species with a wide European distribution (sessile oak and common beech). This gradient was repeated in two parallel valleys, distant from 30 km. Altitudinal trends were investigated for several morphological, physiological and phenological traits in natural conditions (in situ), in a common garden experiment and in reciprocal transplant experiments (RTEs). The phenotypic variability observed in situ showed significant altitudinal trends for all the studied traits and followed similar patterns for both species. We established that together with temperature, it was also necessary to integrate the variations of atmospheric gas partial pressure along the altitudinal gradient. In the common garden experiment, our results showed that the altitudinal gradient induced genetic differentiations for growth, leaf phenology and several morphological and physiological traits. This experiment made it possible to demonstrate, for both species, a weaker effect of genetic variations than in situ observed variations, suggesting a strong effect of the environment on leaf functional traits. A higher intrapopulation than interpopulation genetic variability was also observed for all traits. Finally, the reciprocal transplant experiments highlighted a high magnitude of phenotypic plasticity whatever the trait and the species
Vivas, Nicolas. "Recherches sur la qualité du chêne français de tonnellerie (Q. Petraea Liebl. , Q. Robur L. ) et sur les mécanismes d'oxydoréduction des vins rouges au cours de leur élevage en barriques." Bordeaux 2, 1997. http://www.theses.fr/1997BOR20504.
Trontin, Jean-François. "Caractérisation et variation d'une famille multigénique, l'ADN ribosomique 5S nucléaire, chez quatre espèces forestières des genres larix M. (Pinaceae) et Quercus L. (Fagaceae)." Nancy 1, 2000. http://docnum.univ-lorraine.fr/public/SCD_T_2000_0186_TRONTIN.pdf.
Lepais, Olivier. "Dynamique d'hybridation dans le complexe d'espèces des chênes blancs européens : chênes pédonculés - Quercus robur L., sessiles - Q. petraea (Matt.) Liebl., pubescents - Q. pubescens Willd. et tauzins - Q. pyrenaica Willd." Thesis, Bordeaux 1, 2008. http://www.theses.fr/2008BOR13624/document.
Hybridisation is a complex process with diverse consequences on species evolution. Hybridisation is difficult to study when species are not clearly morphologically distinguished. Our aim was to study the role of hybridisation in the evolution of the European white oak species complex. We used population genetic tools to quantify contemporary interspecific gene flow and to study the mating system of four oak species. A fast genetic analysis protocol was developed and genetic assignment methods were first tested by simulation and then used to determine the species of each tree and to identify hybrids. These methods revealed that hybrid percentages were between 10 to 30% depending on the natural population studied and that all species pairs were involved. We showed that the census number of species in the stands had an influence on hybridisation dynamics and on introgression direction. We studied the mating system of these species in controlled crosses and in the forest to understand the maintenance of species despite interspecific gene flow. Several reproductive barriers contribute to a partial isolation of species, mostly pre-reproductive and prezygotic. A paternity analysis of maternal progenies sampled in the forest showed that first generation hybridisation was rare but that F1 hybrids were fertile and were mating mostly with one of the two parental species, creating numerous backcrosses that explain the high percentages of hybrids observed in the natural populations studied. Hybridisation and introgression are active processes in oaks and contribute to the evolution of the species complex
Arramon, Gilles. "Les triterpènes et lignanes des bois de chêne européen Quercus robur L. Et Quercus Petraea Liebl. : quantification et apports qualitatifs aux eaux de vie d'Armagnac." Bordeaux 2, 2001. http://www.theses.fr/2001BOR20882.
Jurkštienė, Girmantė. "Paprastojo (Quercus robur L.) ir bekočio (Q. petraea [Matt.] Liebl.) ąžuolų hibridizacija, atsikūrimas ir poveikis dirvožemio mikrobiotai." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2014. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2014~D_20141118_150756-77192.
This study analyzes hybridization of pedunculate (Quercus robur L.) and sessile (Q. petraea [Matt.] Liebl.) oak in forest Trakas (Alytus district), including the following processes related to hybridization: the prevalence of oak undergrowth, leaf litter fall and its biochemical composition, impact on soil microbiota. This study differs from other studies carried out in Europe by its specifics, since the research object is situated at the edge of the natural distribution of sessile oak. It was found the increase of the number of hybrid oaks in the undergrowth. A comparative taxonomic analysis of the parental trees of the Trakas forest showed that the variation of morphological traits of leaves of interspecific hybrids of pedunculate and sessile oaks was higher at juvenile age if compared with any paternal species. Molecular-genetic analysis confirmed suitability and effectiveness of the use of leaf morphological traits for species discrimination. Studies confirmed that hybridization process had a character of asymmetric crossings, a limited number of individuals participate in the introgression process. Backcross with one of the parental species – sessile oak prevails. The leaves litter fall of pedunculate oak was distinguished for a higher content of lignin, which determines decreased activeness of bacteria and, especially, micromicetes in the rhizosphere. The decomposition rate of leaves litter fall and organic compounds in rhizosphere under sessile and hybrid oaks were... [to full text]
Barrere, Julien. "Interactions entre chêne et cervidés durant le processus de renouvellement - cas des peuplements forestiers tempérés de plaine (Quercus robur et Q. petraea)." Electronic Thesis or Diss., Université de Lorraine, 2021. http://www.theses.fr/2021LORR0285.
The abundance and spatial distribution of cervids have drastically increased in France, and more generally in the Northern hemisphere over the last decades. These species play a crucial part in the functioning of forest ecosystems, but the current level of their populations compromises the process of forest regeneration for many tree species of crucial importance such as pedunculate and sessile oak (Quercus robur et Q. petraea). The objectives of this thesis are to quantify and unravel the mechanisms underlying the constraint exerted by cervids on oak regeneration through the consumption of acorns, of oak saplings and of admixed understory species, and (ii) to identify how specific forest management operations (i.e. fencing, felling, and clearing) can limit or enhance this constraint. The analysis of a long-term dataset of red and roe deer rumen content sampled in the study site of La Petite Pierre (Northeastern France) showed that acorns represented a significant resource in the diet of these two species, but that their acorn consumption saturated years of high fructification. Using experimental approaches, we showed that simulated deer browsing on the apical shoot systematically reduced oak sapling height growth both in situ and ex situ, and this was explained by a relatively poor plasticity in resource allocation following browsing to compensate for the loss of tissues. The analysis of a network of fenced-unfenced plots located in several sites in France and in Sweden showed that felling to increase canopy openness enhanced the negative effect of cervids on oak sapling growth and survival through a higher frequentation of cervids under open canopies. Lastly, after implementing the process of herbivory in a forest dynamic model (i.e. Regeneration library of CAPSIS modelling tool), I conducted simulations that suggested that under a high browsing pressure, less frequent clearing operations maintaining highly palatable sapling species such as hornbeam could reduce the negative influence of cervids on oak regeneration. To conclude, this thesis results confirm that cervids exert a significant constraint on the process of oak regeneration, but also suggest that adapted management of the understory vegetation could reduce this constraint and contribute to restore a balance between wildlife and silvicultural activities
Bou, Manobens Jordi. "Efectes del canvi global a les rouredes de Quercus petraea al NE de la Península Ibèrica." Doctoral thesis, Universitat de Girona, 2019. http://hdl.handle.net/10803/667404.
El roure de fulla gran Quercus petraea és àmpliament present a centre Europa. Les poblacions del NE de la Península Ibèrica es trobarien al seu límit meridional de distribució i les de condicions més mediterrànies en el xeric limit per aquesta espècie. Els resultats de la tesi, mostren que la comunitat ha canviat la seva composició d’espècies des de la segona meitat del s. XX, però de forma sensiblement diferent segons cada regió. La dinàmica de les rouredes de roure de fulla gran és, doncs, la de recuperació del canvi dels usos del bosc, i el Montseny és bon exemple d’aquest procés; però, en canvi, per algunes rouredes com les del Montnegre, el canvi climàtic presenta un futur incert. Per aquest motiu és important aprofitar les localitats que es troben en refugis naturals com a reservoris i punts on poder conservar aquest hàbitat
Collet, Catherine. "Effet compétitif de deux graminées forestières sur des jeunes chênes sessiles en conditions contrôlées : interaction avec une sécheresse édaphique." Nancy 1, 1994. http://www.theses.fr/1994NAN10029.
Schröder, Jens. "Zum Einfluss der Witterung auf Wuchsverhalten und Vitalität der Trauben-Eiche (Quercus petraea [Matt.] Liebl.)." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-131592.
Sessile oak (Quercus petraea [MATT.] LIEBL.) is an important tree species in the northeastern lowlands of Germany. The widespread introduction of the species into mature Scots pine (Pinus sylvestris L.) stands as a means of ecological forest conversion has further enhanced its relevance in forest science and management. For a few decades, however, increasing numbers of trees and stands showing a severe decline in vitality have led to critical discussions on the possible role of oaks in today's forest development strategies. The adaptive capacity of Sessile oak will be further challenged by climate change in the future. In this context, more information is needed on the relations between the vitality status and growth, including the development of these relations in the next decades. Thus, the study investigates the dependencies between annual radial increment in Quercus petraea (measured as tree-ring width, TRW) and individual-tree vitality as well as the effects of climatic variables on TRW on different temporal scales. Investigations were carried out using two sets of trial plots. The core plot sequence K1-K5 comprises five mature mixed stands of Sessile oak with Scots pine along a gradient from Saxony-Anhalt to eastern Poland. Trees are 110-150 years old and grow on sandy and partly podsolic cambisols with average water supply. A set of 20 additional plots was established in mixed oak-pine stands in Brandenburg. In addition to growth and yield data for the whole plot, increment cores were extracted from a representative sample of 20 trees per plot. Time series data of local daily mean temperatures and daily precipitation sum were provided by the Potsdam-Institute for Climate Impact Research. Data for 2007-2060 come from the median scenario of the regional climate model "STAR 2" based on the SRES-scenario A1B and assumes an increase in temperature of two Kelvin until 2060. Individual vitality was recorded from 2006 to 2011on the core plots (i) according to the European standard method for the assessment of crown condition based on defoliation percentages in summer (EICHHORN et al. 2006) and (ii) following the approach by KÖRVER et al. (1999) for crown structure classification in winter. Both methods were applied to all dominant and co-dominant oaks in the five subsequent years. Trees on the additional plots were assessed only once. Because they are regarded a reliable indicator of tree vitality, annual radial increment as expressed in tree-ring width (TRW) and the resulting growth rate (tree-ring index) are at the center of the analyses. For TRW time series the parameters autocorrelation and sensitivity were calculated both for the whole investigation period and as floating means ("moving windows"). The program "CLIMTREG" (BECK et al. 2013) was applied to eliminate long-term trends in individual TRW series by means of cubic spline functions and to minimize auto-correlation within the resulting TRI time series. Pointer years were identified on the basis of the mean and standard deviation of annual TRI distributions. Plot-specific "chronologies" were calculated as arithmetic means of all "typical" tree-specific TRI series per plot. To analyze the relations between climate and growth, the programs CLIMTREG (for daily climate data resolution) and "bootRes" for R (monthly resolution; ZANG & BIONDI 2012) were applied to local climate data and the TRI chronologies. The repeated assessments show that during the interval 2006-2011 crown condition as expressed in summer foliage as well as in crown structure has improved considerably. Crown structure values are correlated more closely to individual basal area increment than defoliation percentages. At the same DBH, trees with larger crowns exhibit a significantly better crown structure and less defoliation. Annual radial increment has been increasing on the core plots over the past decades, thus the increment level of the dominant trees is on average slightly higher than that of the first yield class in the table by ERTELD (1963). On the additional plots, mean TRW is parallel to yield table values but shows a slowly decreasing trend in a number of stands. The two core plots in Poland exhibited the highest radial increments 2006-2011, both absolutely and relatively. On the annual level, TRI time series are correlated more closely to precipitation sums than to annual mean temperatures. Except for one of the additional plots, the respective correlation coefficients are statistically insignificant. Correlations did not increase when climate parameters were calculated exclusively for the vegetation period instead of the whole year. According to dendroclimatological analyses on the monthly scale with bootRes, trees on core plots K1 and K3 respond almost similarly to climatic influences: High TRI values are related to above-average precipitation mainly during the winter months, as well as in late summer and early fall of the year of growth. On the other core plots, dependencies are less clear. The relations of TRI to monthly temperature are weaker than those to precipitation with the same ranking of plots regarding their sensitivity. The most favorable influence on TRI is exerted by cool spring to early summer months in the year of growth. Correlation patterns are very similar for both dominant and suppressed trees. Separate analyses of the first and the last half of the investigated interval show that the strength of correlations between TRI and climatic variables has been increasing over the past decades. When summarized over all plots, there were distinctly more significant correlation coefficients in the period from 1984-2006 than from 1951-1983. The analyses using CLIMTREG showed that high summer precipitation in the preceding year clearly promotes above-average TRI values. Another conspicuous climate-influenced time period ranges from late November to February with positive correlations both to precipitation and to temperature (at least partly). The third important period for TRI in most trees on the core plots starts in early April and lasts until Mid-July. During this time, high TRI values are correlated with low temperatures and high precipitation. For most of the plots, the average modeled TRI is higher if the second half of the data interval 1951-2006 is used for calibration rather than the entire interval or its first half. The results of the models based on different calibration periods do not differ very much in terms of the identified variables (i.e. length of influential period and type of climatic parameter). However, the direction of correlations becomes more variable in the more recent past. The results of this study are summarized in a number of risks and opportunities regarding future vitality and growth of Sessile oak under regional conditions. Finally, several options of silvicultural management to support vitality and growth of the species are recommended. These consist basically in promoting favorable conditions and limiting negative influences. A large crown with dense foliage and a well-developed root system are crucial conditions for individual vitality which should be strengthened for instance by reducing stand densities at an early age. Mixed stands have a higher stability towards disturbances and provide more diverse habitats for natural antagonists against defoliators. The relatively weak competitiveness of oaks should be taken into account when advocating mixed stands. Regeneration activities should enhance genetic diversity, promote phenotypes with above-average vitality, and accelerate the adaptation of the species by "assisted migration" of drought-tolerant provenances. Competition for water may be eased by lower stand densities. However, the canopy should be kept sufficiently closed to prevent excessive growth of ground vegetation or increased evapotranspiration. An adapted system to monitor forest growth and vitality should be used to technically assist the species in counteracting major insect outbreaks and other severe biotic risks as early as possible. On a more general level, productive discussions are needed between all stakeholders, interest groups, and the public on the social and political role of forests and the required level of management. This should lead to a stable social and political appreciation of forestry and provide the resources and staff necessary to cope with an uncertain future
Bakour, Riad. "Influence de l'espèce et de la provenance des deux principaux chênes français (Quercus robur L." Phd thesis, ENGREF (AgroParisTech), 2003. http://pastel.archives-ouvertes.fr/pastel-00000871.