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See detailContribution à l’amélioration de l’épidémiosurveillance des maladies animales en Afrique francophone de l’Ouest et du Centre
Ouagal, Mahamat ULg

Doctoral thesis (2014)

Livestock is an important source of income in most developing countries. In Africa, it often makes up 10% to 20% of the gross national product at level. One of the major constraints to the development of ... [more ▼]

Livestock is an important source of income in most developing countries. In Africa, it often makes up 10% to 20% of the gross national product at level. One of the major constraints to the development of this sector is animal diseases, which sometimes generate significant economic losses with social consequences that are often very burdensome for farmers. They restrict trade between countries. Reducing the impact of these constraints necessarily involves the prevention and the control of diseases. For this purpose, an adequate knowledge of the epidemiology of the diseases is a prerequisite to define a strategy for their prevention and/or the design of appropriate monitoring measures. One of the essential tools of production remains the epidemiological information network for the surveillance of animal diseases. It is also a tool for decision in international trade involving livestock products. For this purpose, its effectiveness is a guarantee for its credibility. An effective network system must be well organized, meet scientific standards and satisfy the efficiency characteristics which are sensitivity, specificity, acceptability, responsiveness and cost. In west and central Africa, epidemiological surveillance networks of animal diseases are mostly created in the 1990s through the Pan African Program for the Control of Epizootics. A 2004 assessment carried out by this program revealed that these networks are at different stages and found weaknesses in their efficiency. To contribute to the improvement of these systems, an analysis of some performance parameters of these networks has been conducted and suggestions for improvement were made. To achieve this overall objective, the following specific objectives were listed: (i) analyze the technical and functional organization of epidemiological surveillance networks in West and Central Africa; (ii) compare the effectiveness of active surveillance and passive surveillance, the two main monitoring methods used by the networks in West and Central Africa using the case study of the epidemiological surveillance network, in Chad, namely REPIMAT; (iii) assess the sensitivity of an epidemiological surveillance network from an approach based on prevalence of a disease such as Foot and Mouth Disease; (iv) develop performance indicators for regular monitoring of the epidemiological surveillance network for animal diseases in West and Central Africa, again by taking the case of REPIMAT; and finally, (v) estimate the cost incurred by an epidemiological surveillance network in West and Central Africa, for example the REPIMAT. Each of these specific objectives leads to a specific study of which results are presented below: Organization of epidemiological surveillance networks in West and Central Africa The survey on technical and institutional organizations networks in west and central Africa was organised on the basis of a written questionnaire. It involved nine networks of which five were in West Africa (Senegal, Burkina Faso, Ivory Coast, Togo, Guinea) and four in Central Africa (Cameroon, Central African Republic, Democratic Republic of Congo and Chad). The results of this survey showed that the oldest epidemiological surveillance network is that of Chad, REPIMAT. There are more similarities than differences between these networks. In general, network monitoring of animal diseases in west and central Africa are technically and institutionally well formalized. The establishment and operation of the networks surveyed are mainly financed by foreign aid. In general, these are epidemiological surveillance networks that monitor several diseases. All countries surveyed have a central national laboratory for the analysis of samples collected. However, only four countries (Cameroon, Côte d'Ivoire, Guinea and Senegal) can make a diagnosis of all diseases selected for monitoring. The laboratories are considered as partners with surveillance networks in most of the countries surveyed. All networks use the PID/ARIS for data management. In addition to the latter, countries such as Guinea, DRC, Senegal and Chad use a national database developed with Access®. On average, 26% of veterinary stations on the total networks surveyed are involved in the monitoring. This proportion varies from 7% to 91%. However, insufficient diagnostic capacity of laboratories and inadequate operational steering committees are the two main weaknesses of the networks concerned with this survey. Comparison between active and passive surveillance within the network of epidemiological surveillance of animal diseases in Chad The comparison between active and passive surveillance involved 106 REPIMAT surveillance stations randomly divided into 52 active surveillance stations and 54 passive surveillance stations. Vaccination status of nine diseases and their respective prevalence levels are monitored by the network. A work plan was developed for each station. The stations of active surveillance make monthly visits to four herds (villages) to look for monitored diseases and also organise four information meetings with farmers how to react in case of suspicion of the monitored diseases. Passive surveillance stations only organise, monthly, four information meetings with farmers. Suspicions in each station are recorded on a specific form developed for each disease. The agent mentions if the suspicion is performed following a breeder call, a visit from herds or a sensitization meeting. Monitoring lasted 24 months. The results of this study showed that regardless of the type of surveillance, diseases monitored with the exception of rare diseases (Rinderpest, and Rift Valley fever) are reported by the monitoring agents. However, we note that the number of calls recorded following suspicions of farmers (41%) was significantly higher (p <0.05) than suspicions made during visits to herds (30%) or in meetings (29%). For moderately prevalent diseases, the suspicions are mainly calls farmers (77%) and regardless of the type of monitoring (73% for active surveillance and 84% for passive surveillance). On the other hand, for FMD, a disease with high prevalence, 37% of suspicions are recorded by visiting farms. Overall, no significant difference was observed between the types of surveillance because of a low rate of disease onset during sensitization meetings by the active surveillance stations. Passive surveillance stimulated by awareness meetings appears to be a mode for surveillance in the conditions of Chad and cheaper. However, for rare diseases, the specific methods of active surveillance (such as, for example, sentinel flocks) seems preferable. Evaluation of the sensitivity of the animal disease epidemiological surveillance network for Foot and Mouth Disease in Chad Evaluation of the sensitivity of the animal disease epidemiological surveillance network for Foot and Mouth Disease in Chad The study on the network sensitivity was carried out in REPIMAT by taking the surveillance of FMD as an example. FMD is the disease most frequently suspected by REPIMAT. However, the reporting of cases is limited to clinical suspicion. The samples for the purpose of laboratory diagnostic for confirmation of these suspicions are not made. In order to assess the sensitivity of REPIMAT for this disease, a serological survey was conducted in eight of the nine regional delegations with the highest cattle population of the country. The samples were analyzed by the National Reference Laboratory for FMD in Brescia (Italy) with the support of the European Commission action against FMD. The 3ABC and SP-ELISA tests were used for the detection of antibodies and the serotype of the virus. The number of FMD suspicions reported within the network was compared with the seroprevalence. Epidemiological information on the disease, including the circulating serotypes in Chad, was also provided. A total of 796 cattle sera were collected. The seroprevalence rate at individual level was 35.6% (95% CI: 32.2 to 39.0) and that at the herd level was 61.9% (95% CI: 51.9 to 71.2). A strong correlation was observed between the estimated prevalence and number of clinical suspicions reported within REPIMAT. The disease is present in all livestock regional delegations surveyed with a high prevalence in the delegations located in the south, the wettest area, and where cross-border movements are the most important. Serotypes A, O, SAT1and SAT2 were identified. Development of operating performance indicators of Chad epidemiological surveillance network for animal diseases: REPIMAT The maintenance and effectiveness of a disease monitoring system requires regular evaluation to identify timely deficiencies that may occur. For this purpose, the performance indicators are essential tools. One approach for developing performance indicators as well as their application in the operation of 43 monitoring stations REPIMAT was carried out. An analysis of the objectives and operation mechanism of REPIMAT allowed retaining three main components, namely the field workers, the animation cell and the laboratory. The activities of each of these components were listed. The analysis of the outcomes of these activities resulted in the development of the performance indicators that can be used in the operation of REPIMAT. The application of these indicators has highlighted the weaknesses of each component. Estimated cost of a network for animal diseases epidemiological surveillance in Central Africa: the case of Chad network In sub-Saharan Africa, most of the networks for epidemiological surveillance of animal diseases were temporarily financed by external aid. The sustainability of such decision support tools should have been insured by national public funds. The objective of this study was to estimate the costs involved in running an animal disease epidemiological surveillance network by taking the example of such network in Chad (REPIMAT) and its weight in the state budget. These costs were then compared to those of other epidemiological surveillance in West Africa networks. The results of this study showed that the total annual operating and implementing cost of REPIMAT is estimated at € 666 349 (437 096 291 FCFA) for the entire system comprising 106 monitoring stations constituting the local level, 26 livestock sectors, nine regional livestock delegations representing the intermediate level and an animation cell constituting the central level. This cost represents only 3% (2% of fixed costs and 1% of variable costs) of the budget allocated by the Chadian Ministry of Livestock. Fixed costs (72%) weighed more than variable costs (28%) regardless of the levels of intervention. This estimate is similar to the estimated costs of epidemiological surveillance networks in Benin, Ghana, Mauritania and Senegal. Considering only the variable costs (operation), the annual cost of operating a surveillance station, the most important entity in the system was only 932 € or 611 352 FCFA. The surveillance cost is mainly related at the local level (surveillance stations) and intermediate level (livestock sectors and regional livestock delegations) to the cost involved in health surveillance as well as the equipment it requires. This thesis allowed to analyze some parameters of effectiveness of a surveillance network for animal diseases including general organization, type of surveillance, sensitivity, cost and to develop a tool for continuous monitoring of operating a network. It is difficult to meet all the efficiency criteria of an animal disease surveillance network, however, the few parameters studied which are interrelated will help if they are used properly to improve the efficiency of an epidemiological surveillance system of animal diseases in sub-Saharan Africa. [less ▲]

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See detailExercices pratiques de lois de base
Goblet, Cédric; Grandjean, Geoffrey ULg

Learning material (2014)

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See detailLe créateur de carton de tapisserie au XVIe siècle. Remarques méthodologiques à partir de l’activité du peintre Michel Coxcie (1499-1592)
Laruelle, Anne-Sophie ULg

Conference (2014, January 30)

Cette communication se propose de revoir, d’une manière large, les questions liées à « l’auteur » en tapisserie, en les envisageant dans le cadre de l’activité de Michel Coxcie. Artiste de cour et peintre ... [more ▼]

Cette communication se propose de revoir, d’une manière large, les questions liées à « l’auteur » en tapisserie, en les envisageant dans le cadre de l’activité de Michel Coxcie. Artiste de cour et peintre officiel de la Ville de Bruxelles, Coxcie est de loin le plus inventif et le plus productif dans le domaine de la conception de pièces tissées entre les années 1540 et 1563. Nous verrons que la contribution du « Raphaël flamand » à la tapisserie est délicate à appréhender et se présente certainement comme la plus problématique de l’ensemble de son activité (en raison des transformations dues au passage du patron vers le textile, des multiples intervenants au sein de l’atelier…). Enfin, considérer en parallèle l’activité des autres cartonniers romanistes flamands (Bernard Van Orley, Pieter Coecke, Pieter de Kempeneer) et des artistes présents en Italie (Johannes Stradanus) peut assurément contribuer à une meilleure compréhension de ces problèmes et fournir des indications sur la méthode à adopter. L’objectif est également de déterminer les limites de notre propre enquête. [less ▲]

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See detailÀ la Chandeleur, la crêpe reprend vigueur
Frankinet, Baptiste ULg; Lempereur, Françoise ULg

in Culture, le Magazine Culturel de l'Université de Liège (2014)

Entretien avec Françoise Lempereur autour de l’origine de cette fête et des multiples coutumes qui y sont liées

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See detailLa philosophie schizophrénique
Englebert, Jérôme ULg

Scientific conference (2014, January 30)

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See detailQuadratic reformulations of nonlinear binary optimization problems
Crama, Yves ULg

Conference (2014, January 30)

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See detailTechniques additives vs techniques conventionnelles-les microstructures
Mertens, Anne ULg; Lecomte-Beckers, Jacqueline ULg

Conference given outside the academic context (2014)

Très flexibles et particulièrement bien adaptées à la production de petites séries, les techniques additives suscitent un intérêt croissant, notamment pour la mise en oeuvre de matériaux métalliques. Par ... [more ▼]

Très flexibles et particulièrement bien adaptées à la production de petites séries, les techniques additives suscitent un intérêt croissant, notamment pour la mise en oeuvre de matériaux métalliques. Par-delà la diversité des techniques que ce terme recouvre (laser beam melting, electron beam melting, laser cladding…) et par-delà la variété des alliages qu’elles permettent de mettre en oeuvre, quelques caractéristiques récurrentes se dessinent: 1) La nature fortement directionnelle des procédés additifs, lié au fait que la pièce est fabriquée “couche par couche” 2) Des cycles de chauffe et de refroidissement ultra-rapides, en fonction des déplacements du/des faisceau(x) La présente communication s’attache à illustrer ces deux caractéristiques essentielles des techniques additives au moyen d’exemples touchant aux principaux alliages métalliques (aciers, alliages d’aluminium ou de titane…), et à en dégager les risques et les opportunités qu’offrent les techniques additives du point vue du contrôle et de l’optimisation des microstructures et des propriétés d’usage qui en découlent… [less ▲]

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See detailMathematical modeling od the mitral valve. From local to global hemodynamics
Paeme, Sabine ULg

Doctoral thesis (2014)

Mitral valve dysfunction is a relatively common heart disease which typically requires mechanical valve replacement, with consequent high social and economic costs. More specifically, ischemic mitral ... [more ▼]

Mitral valve dysfunction is a relatively common heart disease which typically requires mechanical valve replacement, with consequent high social and economic costs. More specifically, ischemic mitral insufficiency following myocardial infarction has a dynamic behavior that can lead to failure in its detection in certain patients, creating a situation with increased risk of morbidity and mortality. Improving the tracking and the control of valvular pathologies is therefore crucial, as it offers significant opportunities to improve care, costs and prognosis for patients with this disease. To study heart and cardiac valve dysfunction, cardiologists need information about detailed pressure and flow dynamics around and through the valves, atria and ventricles. However, non-invasive information about pressure is currently limited to indices at specific times and invasive catheterization data, which is more traumatic for the patient, is not usually routinely available. One alternative to this involves mathematical modeling of the cardiovascular system which offers a non-invasive and inexpensive way of studying cardiac and circulatory dynamics. This is particularly beneficial where detailed, continuous measurements may not be practicable. This study consisted of the development of a multi-scale closed-loop model of the cardiovascular system that accounted for progressive mitral valve aperture area over the entire cardiac cycle. This multi-scale model, which included detailed mitral valve and left atrium models, was tested over a range of physiological situations and clinical data. The goal was to validate the model’s ability to reproduce clinically measured physiological and pathophysiological behavior in a manner that would enable a model to be made patient-specific using available data. The resulting model was designed to be made patient-specific, and thus capture and reproduce the patient’s unique hemodynamic state on both global and local scales. In particular, it was shown to provide significant information about the patient’s mitral valve dynamics and the detailed flow dynamics and pressure around it. These data are not currently available without extensive, invasive measurements, and this therefore represents a significant step forward in model-based sensing and diagnosis. It is hoped that the model and methods developed in this study will be a powerful tool in assisting medical teams in investigating, tracking, diagnosing and controlling the cardiovascular system. More specifically, the mitral valve, as well as other similar valves, could be directly monitored to improve the diagnosis, costs and prognosis of valvular dysfunction. Furthermore, the overall results justify detailed in vivo animal experiments to thoroughly validate these models and methods in advance of clinical trials. [less ▲]

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See detailProbabilistic parameterisation of the surface mass balance–elevation feedback in regional climate model simulations of the Greenland ice sheet
Edwards, T.; Fettweis, Xavier ULg; Gagliardini, O. et al

in Cryosphere (The) (2014), 8

We present a new parameterisation that relates surface mass balance (SMB: the sum of surface accumulation and surface ablation) to changes in surface elevation of the Greenland ice sheet (GrIS) for the ... [more ▼]

We present a new parameterisation that relates surface mass balance (SMB: the sum of surface accumulation and surface ablation) to changes in surface elevation of the Greenland ice sheet (GrIS) for the MAR (Modèle Atmosphérique Régional: Fettweis, 2007) regional climate model. The motivation is to dynamically adjust SMB as the GrIS evolves, allowing us to force ice sheet models with SMB simulated by MAR while incorporating the SMB–elevation feedback, without the substantial technical challenges of coupling ice sheet and climate models. This also allows us to assess the effect of elevation feedback uncertainty on the GrIS contribution to sea level, using multiple global climate and ice sheet models, without the need for additional, expensive MAR simulations. We estimate this relationship separately below and above the equilibrium line altitude (ELA, separating negative and positive SMB) and for regions north and south of 77° N, from a set of MAR simulations in which we alter the ice sheet surface elevation. These give four "SMB lapse rates", gradients that relate SMB changes to elevation changes. We assess uncertainties within a Bayesian framework, estimating probability distributions for each gradient from which we present best estimates and credibility intervals (CI) that bound 95% of the probability. Below the ELA our gradient estimates are mostly positive, because SMB usually increases with elevation: 0.56 (95% CI: −0.22 to 1.33) kg m−3 a−1 for the north, and 1.91 (1.03 to 2.61) kg m−3 a−1 for the south. Above the ELA, the gradients are much smaller in magnitude: 0.09 (−0.03 to 0.23) kg m−3 a−1 in the north, and 0.07 (−0.07 to 0.59) kg m−3 a−1 in the south, because SMB can either increase or decrease in response to increased elevation. [less ▲]

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See detailLogiciels d'analyse de textes : typologie et approfondissement des outils d'étiquetage réflexif
Lejeune, Christophe ULg

Scientific conference (2014, January 30)

Cet atelier se compose de deux parties. Dans la première, Christophe Lejeune propose une typologie (en six familles) permettant d'appréhender la diversité les logiciels d'analyse de textes disponibles. Il ... [more ▼]

Cet atelier se compose de deux parties. Dans la première, Christophe Lejeune propose une typologie (en six familles) permettant d'appréhender la diversité les logiciels d'analyse de textes disponibles. Il explicite les apports de chaque famille, ses limites et son ancrage méthodologique particulier (en analyse de contenu, de discours ou par théorisation ancrée). La deuxième partie se concentre sur une seule de ces familles : les logiciels d'étiquetage réflexif (comme NVivo, Atlas.ti ou WeftQDA). Isabelle Duvernoy (INRA, UMR 1248 Agir) présente son expérience avec un de ces logiciels (notamment en termes de préparation du matériau, de codage et de rédaction de mémos). Christophe Lejeune illustre, quant à lui, l'usage des schématisations, les modalités de travail collaboratif et les requêtes textuelles. Ces témoignages permettront d'ouvrir une discussion à propos des atouts de ces outils ainsi que des pièges à éviter. [less ▲]

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See detailLa question du concepteur d’ensembles sculptés au Moyen Âge : le cas des portails occidentaux de la cathédrale d’Amiens
Lekane, Marie ULg

Conference (2014, January 30)

In recent decades, art historians have used the notion of program in order to characterize the structuring of an artistic ensemble by a thought or a common idea which may be of political, aesthetic or ... [more ▼]

In recent decades, art historians have used the notion of program in order to characterize the structuring of an artistic ensemble by a thought or a common idea which may be of political, aesthetic or religious order. The three west portals of Amiens Cathedral lend themselves particularly well to a programmatic reflection because they are homogeneous in their chronology, their implementation and their style. The question is even more relevant in Amiens where the statues appear to be distributed and organized in a particularly harmonious and planned way. Once structural, stylistic and iconographic filiations with earlier buildings taken into account (Notre Dame de Paris, in particular), it should important to highlight some of the Amiens peculiarities. I place this research in line with Cécile Voyer’s remark which states that differences and variations convey precious information on the image makers’ intentions. My idea is to query some iconographic or formal particularities in echo with a figure linclosely associated with the construction process and with the theological-historical context. I am thinking, in particular, of the Council of Lateran IV convoked in November 1215, that is to say ten year before the building of the West portals supposedly started, which was attended by Evrard de Fouilloy, Bishop of Amiens, who is responsible for the reconstruction of the Cathedral from 1218. The eminence of the Dean Jean Halgrin of Abbeville, regent in Theology at the University of Paris and contemporary of the early stages of the reconstruction, invites us to wonder about his possible participation in the design of the overall Amiens. [less ▲]

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See detailPourquoi pratiquer la philosophie dès l'école primaire ?
Herla, Anne ULg

Conference (2014, January 29)

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See detailGibt es einen Standard für Standard?
Münzberg, Franziska ULg

Scientific conference (2014, January 29)

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See detailOn collaboration and competition in scientific community
Bessonov, Kyrylo ULg

Speech (2014)

Competition in sciences is increasing today to the levels that it becomes damaging to the scientific progress. In this talk we will talk about benefits of collaboration of healthy competition. Will also ... [more ▼]

Competition in sciences is increasing today to the levels that it becomes damaging to the scientific progress. In this talk we will talk about benefits of collaboration of healthy competition. Will also concentrate on negative aspects of competition and will provide detailed examples illustrating each of the negative points of stiff competition. In addition historical outlook of the scientific community organization and formalization of science will be briefly touched upon in the talk [less ▲]

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See detailMetallographic analysis and damage characterization of Pt-Rh alloy
Reginster, Sylvie ULg

Conference given outside the academic context (2014)

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See detailAnalyse de discours et sciences sociales. Rencontre et malentendu
Lejeune, Christophe ULg

Scientific conference (2014, January 29)

Historiquement, les sciences sociales ont développé différentes techniques pour analyser le matériau langagier. Les recherches sur les média ont inventé l'analyse de contenu pour mesurer la propagande ... [more ▼]

Historiquement, les sciences sociales ont développé différentes techniques pour analyser le matériau langagier. Les recherches sur les média ont inventé l'analyse de contenu pour mesurer la propagande dans les journaux. L'analyse de discours a équipé les sciences du langage. Pour exploiter leurs entretiens, les sociologues se sont dotés de l'analyse par théorisation ancrée. Plusieurs décennies après leur élaboration, ces techniques sont mobilisées indépendamment de leur origine disciplinaire, du type de matériau et de la question de recherche. Cette autonomisation méthodologique peut séduire. Elle entretient cependant une certaine confusion entre technique et méthode. Partant d'illustrations concrètes, Christophe Lejeune plaide pour un recours raisonné aux techniques, qui n'entrave ni la rigueur, ni la réflexivité, ni l'inventivité méthodologique. [less ▲]

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See detailLes aventures du corps et de l’identité dans la photographie de mode
Dondero, Maria Giulia ULg

in Nouveaux Actes Sémiotiques (2014), 117

L’objectif de ce travail est d’explorer certaines caractéristiques de la photographie de mode : en premier lieu, les façons dont elle se met en scène en tant que photo de mode, et en second lieu, les ... [more ▼]

L’objectif de ce travail est d’explorer certaines caractéristiques de la photographie de mode : en premier lieu, les façons dont elle se met en scène en tant que photo de mode, et en second lieu, les manières dont elle-même théorise le fonctionnement plus général de l’univers de la mode. [less ▲]

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See detailA côté des produits de la prairie, quels aliments pour complémenter les rations des vaches laitières ?
Beckers, Yves ULg

Conference given outside the academic context (2014)

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See detailInfluence du changement climatique sur l'accroissement du hêtre en Wallonie
Latte, Nicolas ULg; Claessens, Hugues ULg

Conference (2014, January 28)

Depuis quelques décennies, des signes d’affaiblissement de plus en plus marqués ont été observés sur le hêtre (Fagus sylvatica L.) un peu partout en Europe. L’inquiétude grandissante des gestionnaires ... [more ▼]

Depuis quelques décennies, des signes d’affaiblissement de plus en plus marqués ont été observés sur le hêtre (Fagus sylvatica L.) un peu partout en Europe. L’inquiétude grandissante des gestionnaires forestiers s’inscrit dans la problématique complexe du changement climatique. Une étude dendroécologique a donc été réalisée afin de mieux comprendre la relation entre l’accroissement du hêtre et son environnement. Des mesures de cernes ont été effectuées sur des échantillons de bois issus de 158 hêtres sélectionnés dans douze hêtraies (de 84 à 206 ans) situées le long du gradient climatique de Wallonie (de 67 à 590 m d’altitude). L’analyse de l’évolution temporelle de l’accroissement et de sa relation avec le climat a abouti à 3 résultats majeurs : (1) l’accroissement du hêtre a augmenté à partir des années 30 puis à diminuer de manière soutenue à partir des années 1980, (2) la sensibilité climatique des hêtraies a aussi fortement augmenté et cette augmentation est plus forte pour les peuplements de base altitude, et (3) les températures plus élevées en été et en début d’automne ont un impact négatif de plus en plus prononcé sur l’accroissement. Le réchauffement global rend les arbres de plus en plus dépendants de l’eau disponible (précipitation et sol). Les sécheresses et canicules plus fréquentes et intenses semblent progressivement affaiblir les arbres que puissent de plus en plus dans leur réserve. L’étude comprend une discussion complète intégrant l’interprétation écophysiologique des résultats mis en évidence. [less ▲]

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See detailEtude de la croissance et du niveau de production des peuplements résineux en Wallonie
Perin, Jérôme ULg

Conference given outside the academic context (2014)

Nos recherches visent à améliorer les connaissances de base en sylviculture et en écologie des essences résineuses dans l’optique d’une gestion forestière à vocation principale de production de bois de ... [more ▼]

Nos recherches visent à améliorer les connaissances de base en sylviculture et en écologie des essences résineuses dans l’optique d’une gestion forestière à vocation principale de production de bois de qualité. Nos études se focalisent principalement sur les futaies équiennes pures de douglas, d'épicéa et de mélèzes mais il est prévu de les étendre aux peuplements mélangés d'épicéa-douglas. D'un point de vue pratique, cette action de recherche vise, à terme, à proposer différents scénarios sylvicoles qui devraient fournir un panel de solutions techniques directement applicables sur le terrain, en fonction des essences elles-mêmes, des stations et des conditions locales particulières auxquelles les sylviculteurs sont confrontés. A cet effet, nous tentons de mieux comprendre les relations liant la croissance en hauteur et en grosseur des arbres avec les caractéristiques des peuplements comme la surface terrière, le volume ou le nombre de tiges. Dans un premier temps, de nouveaux modèles de productivité ont été élaborés pour l'épicéa, le douglas et les mélèzes. Ils permettent une estimation rapide et précise du potentiel de production d'un peuplement à partir de la connaissance de sa hauteur dominante et de son âge. Ces modèles ont été incorporés dans une application informatique simple d'utilisation mise à la disposition du public. Plus récemment, nous avons finalisé la mise au point de nouveaux modèles de croissance en grosseur et d'outils permettant de simuler les prélèvements et la mortalité naturelle. Tous ces modèles et ces outils ont été intégrés au sein d'un simulateur nommé "GYMNOS". Ce module informatique permet de simuler l'évolution des peuplements résineux de la plantation à la mise à blanc et de tester des scénarios sylvicoles. La vitesse de croissance, la rentabilité, la qualité du bois produit, la stabilité des peuplements,... sont actuellement évalués dans GYMNOS en fonction de divers paramètres tels que les densités de plantation, l'âge du peuplement lors de la première éclaircie, l'intensité et la fréquence des prélèvements, le terme d'exploitabilité,... L'analyse critique du résultat de tous ces tests mènera à définir les caractéristiques des nouveaux scénarios sylvicoles optimisés pour les pessières, les douglasaies et les mélézières. [less ▲]

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