References of "Hebert, Jacques"
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See detailEffect of growth rate on the physical and mechanical properties of Douglas-fir in Western Europe
Polet, Caroline; Henin, Jean-Marc; Hebert, Jacques ULiege et al

in Canadian Journal of Forest Research = Journal Canadien de la Recherche Forestière (2017), 47

To quantify the impact of forest management and tree growth rate on the potential uses of Douglas-fir wood, nine physico-mechanical properties were studied on more than 1250 standardized clear specimens ... [more ▼]

To quantify the impact of forest management and tree growth rate on the potential uses of Douglas-fir wood, nine physico-mechanical properties were studied on more than 1250 standardized clear specimens. These were collected from trees cut in 11 even-aged stands (6 trees/stand) located in Wallonia (Southern Belgium). Stands were 40 to 69 years old and the mean tree girth was ca. 150 cm. The mean ring width of the 66 trees ranged from 3 to more than 7 mm. Statistical analysis evidenced significant but weak effects of ring width. So, mean ring width and cambial age of the specimens considered jointly only explain 28 to 40% of the variability of the properties studied. From a purely technological standpoint, maintaining mean ring width under 4 mm/year in juvenile wood and 6 mm/year in mature wood should allow all potential uses of Douglas-fir wood. Our results and the literature demonstrate, however, the importance of genetic selection as a complement of silvicultural measures to improve or guarantee the technological properties of Douglas-fir wood. [less ▲]

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See detailPréserver le bois de structure reste indispensable
Lesire, Cécile; Christiaens, Christophe; Charron, Stéphane et al

in CSTC-Contact (2017), 2017/3

The wood used in our regions as a structural element (Lumber, timber framing) are often made of softwood (spruce, Douglas fir, Scots pine, ...). However, these species of wood do not have sufficient ... [more ▼]

The wood used in our regions as a structural element (Lumber, timber framing) are often made of softwood (spruce, Douglas fir, Scots pine, ...). However, these species of wood do not have sufficient natural durability with respect to biological agents (insects and fungi). However, more and more professionals are wondering if this treatment remains necessary in the case of the presence of a (biodegradable) insulation already treated. In other words, would the treatment of the insulation (eg boron salt), because of its biocidal and volatile nature, also protect the wood structure adjacent to the biological agents ( fungi and insects)? [less ▲]

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See detailIdentification of sprinkling storage facilities for windblown timber using a GIS-based modeling approach
Riguelle, Simon ULiege; Jourez, Benoît ULiege; Hebert, Jacques ULiege et al

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment (2017), 21(2),

After catastrophic storm events, the storage of windblown timber is an effective measure for mitigating economic losses in the forest sector by preventing wood decay, protecting stands from secondary ... [more ▼]

After catastrophic storm events, the storage of windblown timber is an effective measure for mitigating economic losses in the forest sector by preventing wood decay, protecting stands from secondary damage, and regulating the timber supply in the middle and long term. In this study, we first propose a GIS-based methodology for identifying suitable sprinkling storage terminals in Wallonia (Belgium). In addition, we suggest an approach for building a coherent regional network as well as methods for selecting and activating terminals within this network after a storm, depending on the severity and distribution of the damage. The GIS-based approach was used to crosscheck technical requirements related to sprinkling storage according to operational and environmental constraints in the Ardenne, which is the most forested sub-region of Wallonia. A three-step process was employed to identify suitable areas. Nine procurement areas were also delineated according to the regional forest inventory plots as a reference for choosing the terminals that should be included in the regional network and activated after the storm. We generated and evaluated 96 scenarios. In the second step, a network of 30 terminals was suggested, which corresponded to a storage capacity of 4 million m³. This network could facilitate the flexibility in the strategic management of storage after huge storms. The procurement area approach also helps addressing routing and transportation issues in a simple way. The GIS approach facilitates the selection of sprinkling storage terminals, but field validation and enhanced collaboration between public and private landowners and forest owners would still be needed. [less ▲]

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See detailNational Forest Inventories - Assessment of Wood Availability and Use: Belgium (Wallonia)
Alderweireld, Matthieu; Rondeux, Jacques; Latte, Nicolas ULiege et al

in Vidal, Claude; Alberdi, Iciar A.; Mateo, Laura Hernández (Eds.) et al National Forest Inventories - Assessment of Wood Availability and Use (2016)

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See detailNouvelles normes sylvicoles pour les peuplements purs équiennes d'épicéa et de douglas
Perin, Jérôme ULiege; Hebert, Jacques ULiege; Lejeune, Philippe ULiege et al

E-print/Working paper (2016)

Ces documents rassemblent les tables de production (version 2016) représentant les nouvelles normes sylvicoles recommandées pour les peuplements purs équiennes d'épicéa commun et de douglas. Un ensemble ... [more ▼]

Ces documents rassemblent les tables de production (version 2016) représentant les nouvelles normes sylvicoles recommandées pour les peuplements purs équiennes d'épicéa commun et de douglas. Un ensemble de 10 tables de production est présentée pour chaque essence, associant deux densités de plantation (2.5 x 2 m et 2 x 2 m) et 5 classes de productivité (0 à IV). [less ▲]

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See detailIntegrated and systemic management of storm damage by the forest-based sector and public authorities
Riguelle, Simon ULiege; Hebert, Jacques ULiege; Jourez, Benoît ULiege

in Annals of Forest Science : a Multidisciplinary and International Journal (2016), 73

The paper’s goals are to identify key challenges in the currentwindthrow management framework and present a blueprint for howto progress in the settlement of regional strategies.SWOT analyses are used to ... [more ▼]

The paper’s goals are to identify key challenges in the currentwindthrow management framework and present a blueprint for howto progress in the settlement of regional strategies.SWOT analyses are used to highlight relevant issues and opportunities in classical approaches from both the forest-based sector and public authorities’ perspectives. Despite the large body of knowledge that allows decision-makers to react promptly after huge storms, strategic responses still suffer from too individual and fragmented decisions and a lack of holistic economic assessments. To tackle these issues, the paper suggests using systemic and integrated risk management approaches. It also presents the ways to enhance the forest-based sector’s resistance and resilience towards economic shock and supports decision-making with the help of systemic analysis. This shift of paradigm is one of the key requirements in optimizing the way of dealing with storm damage, but public authorities should concur with it more actively by improving decisional and administrative frameworks. Contribution of the co-authors Co-authors are PhD thesis’ supervisors and have thoroughly reviewed the paper. [less ▲]

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See detailSupporting integrated and systemic management of windthrow crises by public decision-makers
Riguelle, Simon ULiege; Hebert, Jacques ULiege; Lejeune, Philippe ULiege et al

Poster (2016, April 21)

This poster presents the development of an integrated framework for systemic management of storm damage risk in Wallonia (Belgium) and how it can be implemented throughout the risk management cycle with ... [more ▼]

This poster presents the development of an integrated framework for systemic management of storm damage risk in Wallonia (Belgium) and how it can be implemented throughout the risk management cycle with user-friendly tools and suitable methodologies. [less ▲]

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See detailProduction de nanocellulose à partir de pâte à papier: Hydrolyse enzymatique et valorisation des coproduits dans une stratégie de bioraffinage forestier intégré
Bombeck, Pierre-Louis ULiege; Richel, Aurore ULiege; Jacquet, Nicolas ULiege et al

Conference (2016, January 19)

Présentation succincte de la thématique de recherche doctorale et de son contexte

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See detailL’utilisation de l’hydrolyse enzymatique pour la production de nanocellulose dans une stratégie de bioraffinage forestier intégré (Synthèse Bibliographique)
Bombeck, Pierre-Louis ULiege; Hebert, Jacques ULiege; Richel, Aurore ULiege

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2016), 20(1), 94-103

Introduction. In a world that seeks to break free from petrochemicals, the concept of forest biomass biorefinery is increasingly being studied as a way to maximize the value of the components of this ... [more ▼]

Introduction. In a world that seeks to break free from petrochemicals, the concept of forest biomass biorefinery is increasingly being studied as a way to maximize the value of the components of this biomass. Due to the high added value expected when transforming cellulose fibers into nanocellulose, this technology is highly attractive to the pulp and paper industrial world. <br />Literature. The concept of integrated forest biorefinery is to adapt existing pulp mills so as to maximize the value of the co-products. Through the use of various methods, two types of nanocellulose may be obtained from the cellulose in the pulp. Due to its production of valuable byproducts, enzymatic hydrolysis is an interesting method to use for this purpose, but it must be combined with mechanical post-treatments. The production of nanocellulose from chemical pulp takes place in the final step of pulp production, and could be implemented without modifying the existing mills. The economic viability of this mode of production and the potential market size are the subject of recent studies that appear encouraging. <br />Conclusions. Nanocellulose is a promising biomaterial whose field of application continues to grow. Cellulose in wood pulp can be used as a raw material for the production of nanocellulose using enzymatic pre-treatments that generate valuable co-products. This process can be integrated into a conventional chemical pulp mill and constitutes a broadening of the products available to the pulp and paper industry. [less ▲]

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See detailInfluence of a long-term storage in anaerobic conditions on Norway spruce (Picea abies, L. Karst.) physical and mechanical wood properties
Riguelle, Simon ULiege; Lesire, Cécile ULiege; Hebert, Jacques ULiege et al

in Wood Material Science & Engineering (2016)

Timber storage is a key aspect of storm damage management. After huge storms, sprinkling storage is usually the most used conservation process but anaerobic storage in sealed silos appears as good ... [more ▼]

Timber storage is a key aspect of storm damage management. After huge storms, sprinkling storage is usually the most used conservation process but anaerobic storage in sealed silos appears as good alternative to preserve wood quality over long periods. This paper investigates the impact of long-term (57 months) storage of Norway spruce logs in anaerobic atmosphere on wood properties. Tests were performed on clear wood specimens and on lumbers to determine the modulus of elasticity (E), the static bending strength (σf) and the dynamic bending strength (K). Storage effects on impregnability and colour variation were also studied. Results show no effect of storage on E, σf and K. The naturally poor impregnability of Norway spruce is not improved by the anaerobic conditions, compared to traditional wet storage. Triangle tests reveal no discernible colour variation between logs that underwent anaerobic storage and the control sample. As a conclusion, despite a mould (Gliocladium solani) frequently observed on logs surface after the storage, the process offers ideal conservation conditions. While overall cost remains the main drawback for using anaerobic storage at large scale, the process can be recommended for high value logs, especially since it has few environmental impacts. [less ▲]

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See detailVariation radiale de l'angle des microfibrilles de cellulose et de la longueur des trachéides chez le Douglas
Vaianopoulos, Céline; Hebert, Jacques ULiege; Jourez, Benoît ULiege

Poster (2015, November 04)

Le Douglas (Pseudotsuga menziesii) connaît depuis quelques décennies un essor important en Wallonie, du fait entre autre de son potentiel de croissance supérieur à celui de l’Epicéa. Néanmoins, la ... [more ▼]

Le Douglas (Pseudotsuga menziesii) connaît depuis quelques décennies un essor important en Wallonie, du fait entre autre de son potentiel de croissance supérieur à celui de l’Epicéa. Néanmoins, la sylviculture appliquée à cette essence est généralement calquée sur celle de l’Epicéa, ce qui ne permet pas nécessairement de profiter pleinement du potentiel de l’espèce. Aussi, pour guider l’action des sylviculteurs, une étude visant à évaluer l’impact de la vitesse de croissance sur les propriétés du bois de Douglas a été initiée. Il est admis aujourd’hui que l’angle des microfibrilles de cellulose (AMF) de la paroi des trachéides, ainsi que la longueur des trachéides, en complément de caractéristiques telles que la masse volumique, la largeur des cernes ou la texture, pourraient permettre d’expliquer plus finement le comportement mécanique du bois sans défaut. Afin de tenter de le démontrer, dans un premier temps, l’étude a porté sur les variations de l’AMF et de la longueur des trachéides au sein des arbres en fonction de différents paramètres : la largeur des cernes, l’âge du cerne, la position radiale et la hauteur dans l’arbre. Par la suite, ces résultats seront utilisés pour identifier les relations entre les propriétés mécaniques du bois et ses caractéristiques anatomiques. L’objectif final est de relier les caractéristiques de croissance avec les propriétés du bois produit et d’en déduire des recommandations sylvicoles. [less ▲]

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See detailWIND-STORM: A Decision Support System for the Strategic Management of Windthrow Crises by the Forest Community
Riguelle, Simon ULiege; Hebert, Jacques ULiege; Jourez, Benoît ULiege

in Forests (2015), 6

Storms are one of the most damaging agents for European forests and can cause huge and long-term economic impacts on the forest sector. Recent events and research have contributed to a better ... [more ▼]

Storms are one of the most damaging agents for European forests and can cause huge and long-term economic impacts on the forest sector. Recent events and research have contributed to a better understanding and management of destructive storms, but public authorities still lack appropriate decision-support tools for evaluating their strategic decisions in the aftermath of a storm. This paper presents a decision support system (DSS) that compares changes in the dynamics of the regional forest-based sector after storm events under various crisis management options. First, the development and implementation of a regional forest model is addressed; then, the potential application of the model-based DSS WIND-STORM is illustrated. The results of simulated scenarios reveal that this DSS type is useful for designing a cost-effective regional strategy for storm-damage management in the context of scarce public resources and that public strategies must encompass the whole forest-based sector to be efficient. Additional benefits of such a DSS is to bring together decision-makers and forest stakeholders for a common objective and therefore to enhance participatory approaches to crisis management. [less ▲]

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See detailStudy of durability and the physico-mechanical properties of thermally modified wood
Ninane, Maxime; Jourez, Benoît ULiege; Hebert, Jacques ULiege

Poster (2015, January 30)

Heat-treated wood is a credible alternative for certain kinds of tropical timber. It is also an alternative for certain polluting wood preservatives. This study aims to determine the changes in physico ... [more ▼]

Heat-treated wood is a credible alternative for certain kinds of tropical timber. It is also an alternative for certain polluting wood preservatives. This study aims to determine the changes in physico-mechanical properties and durability of wood that is subjected to heat treatment. For this, we studied five species (oak, ash, natural beech and a variant known as steamed beech, poplar, Douglas-fir). For each species, we had fifteen reference samples and fifteen corresponding treated samples. The results show a decrease in the hygroscopicity and an increase in dimensional stability of heat-treated wood in relation to the degradation of hemicelluloses. The mechanical properties are influence variously, because heat-treated wood is stiffer but also more brittle. The modulus of elasticity increases slightly after treatment. Side hardness and compressive fracture of heat-treated wood may increase up to 30%. On the other hand, the modulus of rupture, the ability to slit and impact may decrease by 50%, 60% and 70%. The durability of heat-treated wood against wood-destroying fungi increases. However, within each species, the durability increase varies greatly. Additional tests conducted to understand this variability, suggests that the heat distribution is not homogeneous within the processing unit. Moreover, our work suggests that durability is related to the fixed carbon content and that this path would be interesting to explore in the future. [less ▲]

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See detailEtude de la qualité du bois d'épicéa conservé sous bâches hermétiques
Riguelle, Simon ULiege; Lesire, Cécile ULiege; Hebert, Jacques ULiege et al

in Forêt.Nature (2015), 137(Octobre-Décembre), 61-68

Le stockage de bois dans des silos hermétiques à l’air est un procédé de conservation original développé en Allemagne au lendemain des tempêtes de 1999. Une expérimentation en conditions réelles sur des ... [more ▼]

Le stockage de bois dans des silos hermétiques à l’air est un procédé de conservation original développé en Allemagne au lendemain des tempêtes de 1999. Une expérimentation en conditions réelles sur des grumes d’épicéa a été menée de 2008 à 2013 à Eupen (Wallonie, Belgique) afin d’étudier l’évolution des propriétés visuelles, physiques et mécaniques du bois conservé via ce procédé et apporter des garanties quant à la valorisation industrielle ultérieure de ces bois. Le taux d’oxygène au sein du silo étanche est resté inférieur à 2 % tout au long du stockage qui s’est déroulé de manière optimale. À l’ouverture du silo, les grumes présentaient un aspect comparable à du bois fraîchement abattu, l’écorce restant adhérente. Cependant, un mycélium blanchâtre superficiel attribuable à Gliocladium solani a été observé sur l’écorce des surfaces exposées de la pile, sans affecter toutefois le bois en profondeur. L’essai de sciage en condition industrielle s’est révélé convaincant pour les professionnels de la filière bois. Les sciages n’ont pas été affectés par les 57 mois de stockage : ils présentaient un aspect et une couleur similaires aux débits caractéristiques provenant de grumes d’épicéa frais. En laboratoire, des essais de caractérisation de la couleur, de l’imprégnabilité, des propriétés physiques (densité, humidité) et mécaniques (module d’élasticité, module de rupture et résilience) ont été effectués sur des échantillons prélevés avant l’ensilage (témoins) et sur des échantillons issus des mêmes arbres prélevés lors de l’ouverture du silo près de cinq années plus tard. Aucune différence statistiquement significative n’a pu être mise en évidence entre les bois témoins et ceux conservés sous bâches hermétiques. Il ressort de cette expérience que la méthode de conservation sous bâches hermétiques peut être envisagée comme une alternative au stockage par aspersion pour des lots de bois chablis de bonne qualité et de forte valeur marchande sans risque de réduction du potentiel de valorisation. [less ▲]

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See detailOak barks as raw materials for the extraction of polyphenols for the chemical and pharmaceutical sectors: a regional case study
Dedrie, Maxime; Jacquet, Nicolas ULiege; Bombeck, Pierre-Louis ULiege et al

in Industrial Crops and Products (2015), 70

Despite their potential for chemical recycling, residues from forest harvesting and wood processing are mostly used for industrial applications with low added value (energy, paper pulp, panels). Bark of ... [more ▼]

Despite their potential for chemical recycling, residues from forest harvesting and wood processing are mostly used for industrial applications with low added value (energy, paper pulp, panels). Bark of both oak species, Quercus robur L. 1753, Quercus petraea (Matt.) Liebl. 1784 is a by-product from sawmill and pulp mill activities. Bark is mainly used as a fuel for the same wood plants. The aim of this study is to look at the feasibility of enhancing the value of this material through the extraction of bioactive molecules such as polyphenols (i.e. catechin, gallic and ellagic acids). First, the effect of industrial storage of logs and bark on their polyphenol content was explored. Then, referring to the selection of tan oaks in the past, the question of an optimum harvesting age is addressed in order to maximize the polyphenol content of the barks. In the end, molecular diversity of bark is examined through the identification of molecules of interest, using different chromatographic analyses. The results show an effect of the industrial context and an effect of the raw material age on the chemical properties of the bark. First investigations also highlight molecules of interest and the molecular diversity, which needs to be further explored. [less ▲]

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See detailInfluence de la vitesse de croissance sur le classement de lames de bardage de Douglas wallon (Belgique)
Pollet, Caroline; Henin, Jean-Marc; Hebert, Jacques ULiege et al

Poster (2014, November 12)

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See detailDétermination de la durabilité des complexes parois et toitures vis-à-vis d’attaques biologiques
Jourez, Benoît ULiege; Hebert, Jacques ULiege; Christiaens, Christophe ULiege et al

Conference given outside the academic context (2014)

Le secteur de la construction est en perpétuel évolution et de nouveaux systèmes constructifs sont proposés aux candidats bâtisseurs. Ils vissent à répondre aux nouvelles exigences de performance ... [more ▼]

Le secteur de la construction est en perpétuel évolution et de nouveaux systèmes constructifs sont proposés aux candidats bâtisseurs. Ils vissent à répondre aux nouvelles exigences de performance (mécanique, acoustique, thermique), de développement durable ainsi qu'à des exigences économiques. Néanmoins, ces nouveaux systèmes constructifs innovants, pour lesquels un manque de recul est observé, doivent encore démontrer leur capacité à maintenir dans le temps leur efficacité initiale et leur durabilité afin d'aboutir à des systèmes performants, durables et sans risques de pathologie. A ce titre, ces complexes, la paroi perspirante et la toiture plate compacte, doivent faire l'objet d'investigations en vue d'évaluer leur durabilité vis-à-vis des attaques par les agents de dégradation biologique. La tendance actuelle s'oriente vers des complexes constitués en majorité de matériaux biodégradables (bois, panneau, isolant naturel) tout en évitant l'emploi de produits nocifs pour la santé des habitants qui sont de plus en plus conscients de leur empreinte écologique et réticents à l'incorporation de substances chimiques potentiellement nocives. Il est à noter cependant que les constituants de ces complexes bien que biodégradables doivent aussi faire preuve d'une durabilité suffisante qui ne devrait pas être limitée à la durée de la garantie décennale assumée par le concepteur/entrepreneur du bâtiment mais s'étendre à la durée de vie de celui-ci. L'origine du projet OPTIDUBO repose sur le fait que le comportement hygroscopique de ces complexes et leur durabilité face à l'attaque des agents biologiques de dégradation (insectes xylophages et champignons lignivores) sont peu connus ou documentés alors que ceux-ci sont de plus en plus utilisés dans la construction d'habitations. Ce chapitre se focalise sur la détermination de la durabilité des complexes parois perspirantes et toiture plate compacte vis-à-vis des agents biologiques de dégradation. Il vise à répondre aux deux questions suivantes:  Dans ces complexes, un ou plusieurs des constituants de la paroi sont-ils attaquables ?  Le traitement de l'isolant au sel de bore est-il susceptible de protéger efficacement le complexe de toute attaque? [less ▲]

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