References of "Thibaut, André"
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See detailAutécologie du merisier
Claessens, Hugues ULg; Thibaut, André; Rondeux, Jacques ULg

in Fiche technique n°20 - Département de la Nature et des Forêts (2011), (20), 37

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See detailSite Index Curves For Alnus Glutinosa (L.) Gaertn. In Southern Belgium: Effect Of Site On Curve Shape
Thibaut, André; Claessens, Hugues ULg; Rondeux, Jacques ULg

in Forestry (2004), 77(2), 157-171

Site index curves were developed for Alnus glutinosa (L.) Gaertn. in southern Belgium. Five models of Duplat and Tran-Ha were fitted to a data set of 15 stem analyses divided into two data subsets clearly ... [more ▼]

Site index curves were developed for Alnus glutinosa (L.) Gaertn. in southern Belgium. Five models of Duplat and Tran-Ha were fitted to a data set of 15 stem analyses divided into two data subsets clearly characterized by different height growth patterns. Model III was found to fit data sets best, both separately and combined. Various statistical comparisons made between the two curve sets underline shape variations corresponding to different soil conditions. A comparison between Belgian and other European curves highlights the effect of the soil on growth curve shape, which is at least as important as that of climatic factors. However, for practical reasons, the use of a general global model, which does not specifically take into account differences in height growth patterns, is satisfactory for productivity evaluation and is recommended for forest management. [less ▲]

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See detailLa forêt luxembourgeoise en chiffres. Résultats de l'inventaire forestier national au Grand-Duché de Luxembourg 1998-2000
Rondeux, Jacques ULg; Wagner, M.; Thibaut, André et al

Book published by Administration des Eaux et Forêts du Grand-Duché de Luxembourg - Service de l'Aménagement des Bois et de l'Economie Forestière (2003)

Ce livre brosse un tableau de la forêt luxembourgeoise sur base de données statistiques obtenues grâce au premier Inventaire Forestier National pour le Grand-Duché, réalisé dans un réseau d'observation ... [more ▼]

Ce livre brosse un tableau de la forêt luxembourgeoise sur base de données statistiques obtenues grâce au premier Inventaire Forestier National pour le Grand-Duché, réalisé dans un réseau d'observation permanent d'environ 5.200 placettes. [less ▲]

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See detailUn modèle de gestion informatisé pour les plantations d'épicéa commun en Ardenne belge
Lejeune, Philippe ULg; Thibaut, André; Pauwels, Dominique

in Les cahiers forestiers de Gembloux (2000), (24), 26

Norway spruce (Picea abies (L.) Karst.) is the first forest species devoted to production in the Wallonian region. Many private and public foresters have to face management problems for these stands ... [more ▼]

Norway spruce (Picea abies (L.) Karst.) is the first forest species devoted to production in the Wallonian region. Many private and public foresters have to face management problems for these stands : rotation length, definition of thinning type, harvesting scheduling, future income and profitability estimation, ... The management model presented in this article can give some answers to these questions. It is made of two components : on one hand, a growth model predicts stand growth in connection with site index and silvicultural parameters, and, on the other hand several modules compute silvicultural indicators (stability index, mortality rate, assortments, ...) and financial indicators (prediction of future incomes and profitability). The management model allows to test and compare in a flexible way different scenarios applicable to stands described by their initial stage (number of stems and basal area per hectare, dominant height). These tools are integrated in a spreadsheet application using Excel TM, which makes it very easy to use by the forest manager who wants to base his managment on objective criteria. [less ▲]

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See detailElaboration de courbes de croissance en hauteur dominante pour les mélèzes (Larix decidua Mill. et Larix kaempferi (Lamb.) Carr.) en Belgique méridionale
Pauwels, Dominique; Thibaut, André; Lejeune, Philippe ULg et al

in Annals of Forest Science : a Multidisciplinary and International Journal (1999), 56(1), 27-34

Site index curves have been determined for Japanese and European larch in Wallonia (Southern Belgium, figure 1). Seven models have been tested (figure 2) to adjust the data from stem analysis in 19 stands ... [more ▼]

Site index curves have been determined for Japanese and European larch in Wallonia (Southern Belgium, figure 1). Seven models have been tested (figure 2) to adjust the data from stem analysis in 19 stands for Japanese larch and in eight stands for European larch (table I). The mean squares of the models have permitted to compare each other (table II). The Duplat et Tran-Ha model IV is the most suitable to describe the dominant height growth. The information issued from 194 temporary plots (134 in Japanese larch stands and 60 in European larch) is used to determine five productivity levels based upon equal intervals of 3 m between 34 and 22 m of dominant height at 50 years (figures 3 and 4). Considering the little height growth difference between the two species of larch (figure 5 and table IV), a unique model is retained (table V). The growth speed is presented in figure 6. [less ▲]

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See detailSite index curves and autecology of ash, sycamore and cherry in Wallonia (Southern Belgium)
Claessens, Hugues ULg; Pauwels, Dominique; Thibaut, André et al

in Forestry (1999), 72(3), 171-182

The work described in this article forms part of an exploratory study whose aim was to determine the main aspects of the autecology of ash (Fraxinus excelsior L.), sycamore (Acer pseudoplatanus L.) and ... [more ▼]

The work described in this article forms part of an exploratory study whose aim was to determine the main aspects of the autecology of ash (Fraxinus excelsior L.), sycamore (Acer pseudoplatanus L.) and cherry (Prunus avium L.) in Wallonia (Southern Belgium). The potential productivity of these species was studied using the site index approach (the height a crop achieves at a given age) which is the most widely accepted means for estimating site quality. As a first step, a set of site index curves were constructed from stem analysis and semi-permanent plots data using the Johnson (1935) and Schumacher (1939) model for ash and the Duplat and Tran-Ha (1986) model II for sycamore and cherry. For ash, dominant height achieved at age 50 is related to various soil-site characters (through adequate multiple regression analysis) in order to make the predictions of site quality applicable to both forested and non-forested land. Furthermore the sites expressed through soil attributes are classified in 'a site catalogue' for each species according to their productivity level. [less ▲]

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See detailConstruction de tarifs de cubage d'arbres pour l’aulne glutineux (Alnus glutinosa (L.) Gaertn.).
Thibaut, André; Rondeux, Jacques ULg; Claessens, Hugues ULg

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (1998), 2(3), 203-213

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See detailTarifs de cubage et paramètres de forme. L'aulne glutineux.
Rondeux, Jacques ULg; Lejeune, Philippe ULg; Thibaut, André et al

in Silva Belgica (1998), 105(6), 7-12

Dans le cadre de cette recherche dont l'un des objectifs finaux est la construction de modèles de croissance, une première étape a été consacrée à l'établissement de tarifs de cubage d'arbres appropriés à ... [more ▼]

Dans le cadre de cette recherche dont l'un des objectifs finaux est la construction de modèles de croissance, une première étape a été consacrée à l'établissement de tarifs de cubage d'arbres appropriés à l'aulne glutineux et à la région de croissance étudiée. Cette démarche était d'autant plus utile que très peu de travaux dendrométriques sont disponibles pour cette essence en Europe. [less ▲]

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See detailTarifs de cubage pour l'aulne glutineux (Alnus Glutinosa (L.) Gaertn.) en Belgique méridionale
Thibaut, André; Rondeux, Jacques ULg; Claessens, Hugues ULg

in Revue Forestière Française (1998), 50(3), 244-250

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See detailTables de production relatives au douglas (Pseudotsuga menziesii (MIRB.) Franco)
Rondeux, Jacques ULg; Thibaut, André

Book published by Les Presses Agronomiques de Gembloux (1996)

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See detailIndices et courbes de fertilité pour les peuplements de douglas (Pseudotsuga menziesii (MIRB.) FRANCO) en Belgique
Thibaut, André; Rondeux, Jacques ULg; Claessens, Hugues ULg

Book published by Faculté universitaire des sciences agronomiques de Gembloux (1995)

Height growth, site index curves and equations for managed even-aged pure stands of douglas-fir under management in the Southern Belgium are presented. They were derived from 256 temporary sample plots ... [more ▼]

Height growth, site index curves and equations for managed even-aged pure stands of douglas-fir under management in the Southern Belgium are presented. They were derived from 256 temporary sample plots, 87 of which were remeasured to give top height periodic increments. The range age and site classes being not equally covered, a special attention was paid to the increments of the total height of dominant trees (1 tree / are of sample plot). A large number of equations were tested to determine which was best suited to express the relationship of age and top height. Regression was employed to fit 4 digitized freehand curves drawn on the average pattern of top heights and top height increments observed at various ages. The form of the JOHNSON-SCHUMACHER model used in this study is : Hdom = b0 exp [-b1/(A-b2)], where : Hdom = top height, A = age, b0, b1 et b2 = coefficients to be estimated by non-linear regression procedures, exp = "e", the base of Naperian logarithms. The coefficients were estimated for the 4 curves. Each of the resulted equations was solved for height at age 50, thereby asigning a site index value to each equation. Site index was introduced into the height-age equation as an independent variable by expressing the coefficients as function of site index itself. Three site index curves corresponding to 36,33 and 30 m attained at age 50 were then derived. The logical issue of this study is to develop a prediction equation based on ecological factors wich should be most correlated with site index. [less ▲]

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See detailLe frêne en Condroz : stations et productivité potentielles
Claessens, Hugues ULg; Thibaut, André; Lecomte, Hugues et al

Book published by IRSIA (1994)

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See detailFacteurs écologiques de production du frêne en Condroz et productivité des stations potentielles
Claessens, Hugues ULg; Thibaut, André; Rondeux, Jacques ULg

in Cahiers Forestiers de Gembloux (1993), 11

The aim of the present study is to correlate site variables with measured site index restricted to pure even-aged or nearly even-aged stands of ash. The site evaluation has been made through 81 ... [more ▼]

The aim of the present study is to correlate site variables with measured site index restricted to pure even-aged or nearly even-aged stands of ash. The site evaluation has been made through 81 experimental plots distributed throughout the Condroz under a wide range of ecological conditions and types of soils. Site index (top height at 50 years) was measured on each plot using tree height-age relationship according to an appropriate methodology [THIBAUT and al., 1992]. In order to appreciate the relative importance of all the observed or measured site factors, plots were grouped in three major groups related to site conditions and defined as follows : alluvial and colluvial sites, flats and slopes either on deep muddy soils or on stony soils. Topographic position, soil depth and soil drainage conditions had the highest correlation with measured site index. These variables and the three site groups have been successfully used as independent variables in a regression model that is an interesting tool for evaluating productive potential of a site for ash even devoid of trees. [less ▲]

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See detailEtablissement de courbes de productivité pour les peuplements de frêne (Fraxinus excelsior L.) en région limono-calcaire du Condroz et de l'Entre-Sambre-et-Meuse
Thibaut, André; Claessens, Hugues ULg; Rondeux, Jacques ULg

Book published by Faculté universitaire des sciences agronomiques de Gembloux (1992)

Site index curves have been prepared for ash stands (Fraxinus excelsior L.) in the region of Condroz and Entre-Sambre-et-Meuse, characterized by the abundance of calcareous loamy soils. The data for this ... [more ▼]

Site index curves have been prepared for ash stands (Fraxinus excelsior L.) in the region of Condroz and Entre-Sambre-et-Meuse, characterized by the abundance of calcareous loamy soils. The data for this study were obtained from 27 permanent sample plots, 48 temporary plots and 10 stem analyses. The three sources of data are dealing with the most main types of ecological conditions of the studied region. They have led to the construction of top height/age curves for ash stands. In order to assess the productivity level of such plantations in Belgium, their site index curves have been compared to those observed in four other European countries. Furthermore, the site index (top height at 50 years) has been related to site characteristics, as soils groups and plants communities, observed into the ash plots. Using the relationships between site index and site factors, an evaluation of site quality form soil and vegetative characteristics can be made regardless of the presence or absence of the forest stand. [less ▲]

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See detailConstruction d'une table de production pour le douglas (Pseudotsuga menziesii (MIRB.) FRANCO) en Belgique
Rondeux, Jacques ULg; Laurent, C.; Thibaut, André

Book (1991)

A general yield table has been compiled for even-aged pure stands of douglas fir [Pseudotsuga menziesii (MIRB.) FRANCO] in Belgium. It reflects the probable development at normal fully stocked stands ... [more ▼]

A general yield table has been compiled for even-aged pure stands of douglas fir [Pseudotsuga menziesii (MIRB.) FRANCO] in Belgium. It reflects the probable development at normal fully stocked stands under the silviculture at the time of the data collection. We have used 256 temporary sample plots, 87 of which have been remeasured 2 or 3 times. A family of functions (the JOHNSON-SCHUMACHER model) has been used to develop a site communication system based on the top height at age 50. The standing crop (number of trees, volume, basal area, basal area mean stem) calculated as a function of age and site index is derived from stem girth distribution fitted by means of the WEIBULL function. Concerning the increments and the thinnings, the corresponding values have been calculated from individual tree girth increments (from borings) and comparison between stem distributions at the beginning and at the end of a period corresponding to a thinning cycle. This table is the heart of a future set of variable density yield tables. The yield of Douglas in Belgium is also compared with the yield observed in next European countries. [less ▲]

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