13 research outputs found
Le XXIIIe CongrÚs mondial de l'IUFRO à Séoul : Sustaining Society and the environnement ? Un bilan vu par les étudiants impliqués au sein de l'IFSA
A number of French students who are members of the International Forestry Students Association (IFSA) were
part of the delegation that attended the 23rd world congress of the International Union of Forest Research
Organisations (IUFRO) for 23 to 28 August 2010 in Seoul, South Korea. This article describes the content and
main results of this important congress for forestry research, presenting the authorsâ views on various
subjects they consider important.Des Ă©tudiants français membres de lâAssociation internationale des Ă©tudiants forestiers (IFSA) ont fait partie
de la dĂ©lĂ©gation qui sâest rendue au 23e congrĂšs mondial de lâUnion internationale des instituts de recherches
forestiÚres (IUFRO) du 23 au 28 août 2010 à Séoul en Corée du Sud. Cet article décrit le contenu et les principaux
résultats de cet important congrÚs pour la recherche forestiÚre et donne le point de vue des auteurs
sur divers sujets qui leur tiennent Ă coeur
Discrete semiparametric regression models with associated kernel and applications
International audienc
A generalized self-thinning relationship for multi-species and mixed-size forests
Introduction: The self-thinning relationship established by Reineke in 1933 assumes a relationship between the number of stems and the quadratic mean diameter in fully stocked pure stands. This rule is extensively used for management purposes, but it has been initially calibrated for pure, even-aged stands for relatively few species. Objectives: Here, we extend this relationship to mixed-species and mixed-size forests through a generalized modeling approach. Reinekeâs rule can be seen as a particular case of this generalized approach. Resource sharing is taken as a starting point; thus, both site fertility and diameter heterogeneity are taken into account. Discussion: Calibration on actual inventories is made on a dataset of 82 French stands. The theoretical relationship is successfully adjusted for species in which enough data were available, namely, common beech (Fagus sylvatica L.), oak (Quercus petraea [Mattuschka] Liebl and Quercus robur L.), and Norway spruce (Picea abies [L.] Karst). Conclusion: Self-thinning exponents obtained for beech and oak (1.86 and 1.76, respectively) can be used in the mixed-species equation that we developed. These results encourage calibrating the parameters for other species if appropriate data are available
Une rencontre europĂ©enne organisĂ©e par les Ă©tudiants de lâIFSA : implication dans le plan dâaction forestier et lâĂ©ducation forestiĂšre
Students at ENGREF Nancy who are members of IFSA (International Forestry Studentsâ Association) organised an international meeting from 10th to 12th May, 2007, bringing together 26 student organizations from all over Europe. 120 people met for lectures and discussion on topical issues relevant to European forests such as competitiveness of the forest-based industries, dendroenergy, changes in forest-based trades, climate change, forest certification, hunting, governance, public awareness-building and student exchanges on a European scale. This event was an unique opportunity for many people to speak about European issues using English to compare notes and share ideas.Les Ă©lĂšves de lâENGREF Nancy, membres de lâIFSA (International Forestry Studentsâ Association), ont organisĂ© du 10 au 12 mai 2007 une rencontre internationale rĂ©unissant 26 organisations Ă©tudiantes de lâEurope entiĂšre. PrĂšs de 120 personnes se sont retrouvĂ©es autour de confĂ©rences et dĂ©bats sur des thĂšmes dâactualitĂ© pour la forĂȘt en Europe, tels que la compĂ©titivitĂ© du secteur forestier, le bois-Ă©nergie, les changements dans les mĂ©tiers forestiers, les changements climatiques, la certification forestiĂšre, la chasse, la gouvernance, la sensibilisation du public et les Ă©changes dâĂ©tudiants Ă travers lâEurope. Cette rencontre a Ă©tĂ© lâoccasion pour beaucoup de parler en anglais sur des sujets dâintĂ©rĂȘt europĂ©en, dans un cadre dâĂ©change et de partage des points de vue
A unique data base in France for individual tree volumes and biomass for use in all-purpose models of wood energy
A base for volume and biomass data of the aerial woody compartments of individual trees was constituted
under the ANR EMERGE (French acronym for âdesigning models for a robust, all-purpose estimation of wood
energyâ) project by seven bodies involved in forest research and management in France (ONF, INRA, Cemagref,
IFN, FCBA, CNPF and CIRAD) so as to come up with a robust model of woody resources in forests. These
measurements, taken for various logging diameters, sometimes down to the slenderest branches, have been
performed since the beginning of the 20th century forming a unique data base in France. The data cover a
broad range of age groups, sizes, species, stand structures and environmental factors (soil, climate). Of particular
interest is the distribution of the available data in relation to French resources as estimated in the
National Forest Inventory so as to use sampling campaigns to collect missing information under the EMERGE
project. Another significant feature is the potential for designing robust, all-purpose models of volumes and
biomass for various logging diameters depending on species, stage of development, geographic gradients,
variations in silvicultural practises and possible effect of date of measurement.Une base de donnĂ©es de volumes et biomasses de compartiments ligneux aĂ©riens dâarbres individuels a Ă©tĂ©
rassemblĂ©e dans le cadre du projet ANR EMERGE (Ălaboration de modĂšles pour une estimation robuste et
gĂ©nĂ©rique du bois Ă©nergie), par sept organismes dâĂ©tude et de gestion de la forĂȘt en France (ONF, INRA,
Cemagref, IFN, FCBA, CNPF et CIRAD), afin de modéliser de façon robuste la ressource ligneuse forestiÚre. Ces
mesures dĂ©taillĂ©es selon diffĂ©rents niveaux de dĂ©coupe, parfois jusquâaux plus fines branches, rĂ©alisĂ©es
depuis le début du XXe siÚcle, représentent une base de données unique en France. Les données couvrent
de larges gammes dâĂąge, de taille, dâessences et structures de peuplements, ainsi que les facteurs environnementaux
(sol, climat). On sâintĂ©resse particuliĂšrement Ă la distribution des donnĂ©es disponibles par rapport
Ă la ressource française estimĂ©e par lâIFN, afin de combler dâĂ©ventuelles lacunes lors des campagnes dâĂ©chantillonnage
prĂ©vues dans le cadre du projet EMERGE ainsi quâĂ la possibilitĂ© dâune modĂ©lisation robuste et
générique des volumes et biomasses à différentes découpes par rapport aux espÚces, aux stades de développement,
aux gradients gĂ©ographiques, aux variations sylvicoles, et en sâaffranchissant dâun Ă©ventuel effet
de la date de mesure
Estimation harmonisée du volume de tige à différentes découpes
National audienceLe volume tige, on connaĂźt... mais pour quelle dĂ©coupe, quelle essence, quelle rĂ©gion voire forĂȘt ? Comment assurer des estimations cohĂ©rentes Ă large Ă©chelle ? Comment anticiper lâĂ©volution des usages, avec des spĂ©cifications (dĂ©coupeâŠ) de plus en plus variables ? La solution : un modĂšle unique paramĂ©trĂ© par essence (ou groupe dâessences), calĂ© sur le volume total, valable partout et modulable selon la dĂ©coupe. Vous en doutez ? EMERGE lâa fait ! En introduisant une nouvelle « entrĂ©e », la hauteur de dĂ©crochement. Attention : pour bien comprendre cet article, il faut avoir lu le prĂ©cĂ©dent
Design and characterization of a single photoelectron calibration system for the NectarCAM camera of the medium-sized telescopes of the Cherenkov Telescope Array
International audienceIn this work, we describe the optical properties of the single photoelectron (SPE) calibration system designed for NectarCAM, a camera proposed for the Medium Sized Telescopes (MST) of the Cherenkov Telescope Array (CTA). One of the goals of the SPE system, as integral part of the NectarCAM camera, consists in measuring with high accuracy the gain of its photo-detection chain. The SPE system is based on a white painted screen where light pulses are injected through a fishtail light guide from a dedicated flasher. The screen â placed 15Â mm away from the focal plane â is mounted on an XY motorization that allows movements over all the camera plane. This allows in-situ measurements of the SPE spectra via a complete scan of the 1855 photo-multiplier tubes (PMTs) of NectarCAM. This calibration process will enable the reduction of the systematic uncertainties on the energy reconstruction of Îł -rays coming from distant astronomical sources and detected by CTA.We discuss the design of the screen used in the calibration system and we present its optical performances in terms of light homogeneity and timing of the signal
Significant differences and curvilinearity in the self-thinning relationships of 11 temperate tree species assessed from forest inventory data
Annuaire du CollĂšge de France 2015-2016
La 116e Ă©dition de lâAnnuaire du CollĂšge de France reflĂšte lâactivitĂ© scientifique de lâinstitution pour lâannĂ©e acadĂ©mique 2015-2016. Elle contient notamment les rĂ©sumĂ©s dĂ©taillĂ©s des enseignements ainsi quâune prĂ©sentation des recherches menĂ©es par les professeurs du CollĂšge de France, leurs laboratoires et Ă©quipes de recherche