How to relate the standing tree shape to internal wood characteristics: Proposal of an experimental method applied to poplar trees

Abstract

-This paper presents an experimental method allowing 3D measurements of the geometry of a standing mature tree to be closely linked to the spatial distribution of internal wood properties. The accuracy of the geometrical information is assessed from repeated measurements performed on 10 mature poplar trees and demonstrates that wind is the most limiting factor. Since the method was developed to study the spatial distribution of tension wood, some pictures of the latter are presented. Furthermore, some preliminary relationships between variables derived from measurements such as the height, the local tree slope, the eccentricity of the tension wood area, or the eccentricity of the disc are discussed to illustrate the potential of the method.standing tree / 3D digitising / internal structure / reaction wood / metrology Résumé -Comment connecter la forme d'un arbre sur pied aux propriétés internes du bois : proposition d'une méthode expérimentale appliquée sur des peupliers. Cet article présente une méthode expérimentale de mesure de la géométrie tridimensionnelle d'un arbre sur pied mature permettant un couplage étroit avec la mesure des propriétés internes du bois. La précision de l'information géométrique est estimée à partir de mesures répétées sur 10 peupliers et met en évidence le vent comme principal facteur limitant. La méthode ayant été développée pour étudier la distribution spatiale du bois de tension, quelques illustrations de cette dernière sont présentées. En outre, des relations préliminaires liant des variables telles que la hauteur, l'inclinaison locale de l'arbre, l'excentricité de la zone de bois de tension ou l'excentricité de la rondelle sont discutées afin d'illustrer le potentiel de la méthode.arbre sur pied / digitalisation 3D / structure interne / bois de réaction / métrologie

Tension wood occurrence in three cultivars of Populus × euramericana. Part I: Inter-clonal and intra-tree variability of tension wood

“…In order to connect the occurrence of tension wood (TW) to the standing trunk shape it was necessary to find a method to calculate the tree shape, the log shape, the discs and the ring properties in the same system of coordinate. In this case, a chain of devices combining laser distancers and image analysis systems was used [14]. The result was a precise location of the characteristics measured on each disc in the standing tree.…”

“…The result was a precise location of the characteristics measured on each disc in the standing tree. Using this information, the local lean per disc or per growth ring could be calculated as the angle between the vertical axis and a line joining the centre of gravity of the disc below and above the disc studied [14]. Then the mean local lean per tree, was calculated as the average of the different local lean per disc analysed in the stem.…”

Assessment of the assortment potential of the growing stock – a photogrammetry based approach for an automatized grading of sample trees

“…As restriction, linking with wood traits and internal defects was not yet realized and can be identified as further development target (e.g. [4,24,29]). Furthermore, stem form related assortment criteria like stem curvature and ovality of the cross section were excluded from the presented approach because the analyzed timber selling contracts did not focus on these stem form attributes.…”

Assessment of tension wood detection based on shiny appearance for three poplar cultivars

“…Three tree-shape indexes were defined on the basis of a tree shape inventory [9]: straight, leaned, and flexuous. One specimen per shape index was finally chosen to model tension wood.…”