References of "Lejeune, Philippe"
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See detailModèles de cubage pour essences multi-tiges : application à des plantations d'acacia
Lejeune, Philippe ULiege; Rondeux, Jacques ULiege

in Cahiers Agricultures (1994), 3(3), 189-194

Tree-volume equations were devised to estimate the volume of wood (excluding bark) of Acacia auriculiformis A. Cunn ex Benth fuelwood plantations in Zaïre. The tables give the total volume of stems and ... [more ▼]

Tree-volume equations were devised to estimate the volume of wood (excluding bark) of Acacia auriculiformis A. Cunn ex Benth fuelwood plantations in Zaïre. The tables give the total volume of stems and branches to an upper girth limit of 9 cm, together with the volumes according to the following classes of girth : 9-14, 15-44 and over 45 cm. Because this species has a high proportion of multiple-stem trees (which begin forking below the breast-height level), girth at 1.30 m is a relatively meaningless concept. Taking the extent of this variable in tree volume estimation into account, various expressions of girth were investigated. Instead of considering each stem girth individually, a "standardised" girth at 1.30 m (from ground level) was adopted. For any given tree, this corresponds to the quadratic sum of all girths measured at 1,30 m. [less ▲]

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See detailUtilisation d'un S.I.G. pour la gestion des ressources forestières : exemple d'application à un inventaire forestier régional
Lejeune, Philippe ULiege; Lecomte, Hugues; Prevot, Hugues ULiege

in Bulletin des Recherches Agronomiques de Gembloux (1993), 28(2-3), 275-286

The development of a Geographic Information System (G.I.S.) leads to new prospects in the field of broad-scale forest inventory, the main objective being to estimate areas and growing stock for the ... [more ▼]

The development of a Geographic Information System (G.I.S.) leads to new prospects in the field of broad-scale forest inventory, the main objective being to estimate areas and growing stock for the different stand types in a given region. The dot grid method typically used to estimate the areas in the case of systematic sampling, can be advantageously replaced by the creation within a G.I.S., of a stand map, that can be overlaid with data issued from the inventory. A methodology is proposed, to produce such a map using color infrared aerial photos at a scale of 1:25,000. Geographical data are processed using ILWIS software. The method has been tested on a 200 km² forest area. The error rate for interpretation of stand types is less than 6 % if one considers the confusions between species. The crossing of this stand map with the sample plots layer provides an estimation of the growing stock per stand type. [less ▲]

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See detailTarifs de cubage peuplement pour le douglas Pseudotsuga menziesii (Mirb.) Franco en moyenne et haute Belgique
Rondeux, Jacques ULiege; Laurent, Christian; Lejeune, Philippe ULiege

in Revue Forestière Française (1991), XLIII(6), 507-513

L'estimation rapide du volume des peuplements de nos principales essences forestières peut être réalisée au moyen de tarifs de cubage de peuplements. Nous avons mis à profit de grand nombre de données ... [more ▼]

L'estimation rapide du volume des peuplements de nos principales essences forestières peut être réalisée au moyen de tarifs de cubage de peuplements. Nous avons mis à profit de grand nombre de données dendrométrique récoltées dans le cadre d'une étude consacrée à la sylviculture et à la production du Douglas, pour établir des tarifs adaptés à la détermination du volume des peuplements de ce résineux en pleine expansion et qui couvre aujourd'hui près de 11 000 hectares en Moyenne et Haute Belgique. Nous présenterons d'abord les caractéristiques du matériel expérimental ainsi que la technique de construction des tarifs et nous fournirons les résultats obtenus pour le volume bois fort tige ainsi que ceux relatifs à différentes découpes, et, nous envisagerons enfin l'utilisation pratique de ces tarifs et rappellerons leur intérêt en matière de gestion forestière. [less ▲]

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See detailEtude technologique de la valorisation par lamellation de chênes indigènes de petites dimensions
Lejeune, Philippe ULiege; Leclercq, André

in Bulletin des Recherches Agronomiques de Gembloux (1990), 25(3), 313-328

The authors have examined the technological feasibility of laminating small sized logs (girth at breast height between 70 and 150 cm) of European oaks (Quercus robur L. and Quercus petraea LIEBL.). This ... [more ▼]

The authors have examined the technological feasibility of laminating small sized logs (girth at breast height between 70 and 150 cm) of European oaks (Quercus robur L. and Quercus petraea LIEBL.). This technique allows indeed to produce from a low grade raw material a product able to compete with solid wood of first choice. The manufacturing of window frames has been taken as an example of the use of laminated oak. The observed output from the sawing of the experimental material seems to point out that only the logs belonging to the girth categories between 105 and 145 cm are really able to be upgraded by this process (output ranging from 19 % up to 28 %). The shrinkage measurements show that the processed raw material is characterized by a low dimensional stability. The effect of the wood species and the kind of glue on the mechanical behaviour of the product has been investigated. Oak has a lower bending strength than merbau but higher than meranti or larch from Oural. Considering the different glues used for this experiment, it has been observed that they give in "dry state" a higher shear strength than solid wood. However, moisture induces to a variable extent a strength loss for all the compared wood adhesives. [less ▲]

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See detailEvaluation des actions anthropiques dans le cadre de l'aménagement agro-sylvo-pastoral de la vallée de la Bougouriba (Burkina Faso)
Lejeune, Philippe ULiege; Hellemans, Ph.; Compère, R.

in Bulletin des Recherches Agronomiques de Gembloux (1989), 24(4), 397-423

Evaluation of natural vegetation affected by human activity in the Valley of the Bougouriba river (Burkina Faso). Utilization of satellite data. The authors analyse the actual situation (state of the ... [more ▼]

Evaluation of natural vegetation affected by human activity in the Valley of the Bougouriba river (Burkina Faso). Utilization of satellite data. The authors analyse the actual situation (state of the natural vegetation and occupation rate by agriculture and stock breeding) in an area under recent colonization, the Bougouriba Valley, located South-West of Burkina Faso. Planning and management of the valley is the task of the "Autorité des Aménagements des Vallées des Volta" (AVV), but important spontaneous migrations of farmers not controlled by the AVV represent a danger for the environment : systematic deforestation, culture on superficial and fragile soils without fallows. While ground observations are necessary to evaluate the phenomenon, the authors have also used a digitalized treatment of thematic maps and satellite imagery to measure the extent of the colonization and the rate of presence on soils that should be reserved for silvo-pastoral activities. Besides, a policy for land use management is proposed with concrete actions for the development of a sedentarised agriculture based on a better association of agriculture and stock breeding. [less ▲]

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