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

Abstract

-The main wood quality problem affecting poplar trees is tension wood occurrence associated to end-splits after felling, distortions of products, woolly wood, etc. The objective of this study was to estimate the occurrence of tension wood by using the external shape of the stem and the 3D distribution of annual growth rings. This paper is the first of two papers and presents the inter-clonal and intra-tree tension wood variability. A clear clonal-effect was observed on tension wood area percentage (I-MC>I214>Luisa Avanzo). The clone with the best tree morphology (I-MC) showed the highest percentage of tension wood (15.3%). Concerning the intra-tree variability, tension wood extent increased significantly at the tree base (< 30-50 cm). In the radial direction of the stem, the percentage of tension wood showed an U-shape distribution. The first peak, close to the pith, corresponds to the "establishment growth period" during the open growth and the second peak, close to the bark corresponds to the "competition growth period". tension wood / poplar / variability / cultivar / secondary growth Résumé -Présence de bois de tension dans trois variétés de Populus × euramericana. Partie I : Variabilité inter-clonale et intra-arbre du bois de tension. Le principal problème de qualité affectant les peupliers est la présence de bois de tension associée aux fentes à l'abattage, aux déformations des sciages, ou au bois pelucheux… L'objectif principal de ce travail est d'estimer la distribution du bois de tension à partir de la forme détaillée de l'arbre et de son empilement de cernes en 3D. Cet article est le premier d'une série de deux, où nous présentons la variabilité inter-clonale et intra-arbre du bois de tension. L'analyse de la variabilité du pourcentage surfacique de bois de tension met en évidence un fort effet clone (I-MC>I214>Luisa Avanzo) et montre aussi que le clone avec la meilleure conformation morphologique (I-MC) présente la proportion de bois de tension plus élevée (15.3 %). En ce qui concerne la variabilité intra-arbre, la proportion de bois de tension présente une augmentation significative à la base de l'arbre (< 30-50 cm). Dans la direction radiale, la distribution du bois de tension présente une structure bi-modale en forme de « U ». Le premier mode du côté de la moelle correspondrait à une phase de croissance libre, dite phase « d'établissement » et le second du côté de l'écorce à une phase de recherche de la lumière dite « phase de compétition ». bois de tension / peuplier / variabilité / cultivar / croissance secondaire

End-use related physical and mechanical properties of selected fast-growing poplar hybrids (Populus trichocarpa × P. deltoides)

“…This was experimentally proven by Jourez et al [11] for P-euramericana cv 'Ghoy'. Badia et al [1,2] reported different patterns of tension wood distribution between clones. They also stated that tension wood extent is highest at the tree base, which is also reflected in the data presented in Table II.…”

Comparaison du bois de tension et du bois opposé de dix arbres provenant d’espèces différentes de forêt tropicale humide

“…When trees have to restore their verticality after some accidental leaning (or partial uprooting), they will produce a rather wide sector of reaction wood on the lower side of the stem for gymnosperms (compression wood), on the upper side for angiosperms (tension wood) [2,3,19,25]. Due to the usual higher growth rate in the reaction wood sector, the total volume of reaction wood in a log can be significant [16,33].…”

Effects of curvature in hybrid poplar on acoustic velocity at the tree level

“…However, as shown by Clair et al (2003) in research on chestnut, rapid growth in some hardwoods can generate an increase in the amount of reaction wood in the stem thereby reducing the economic potential of the resource due to increased shrinking/swelling and distortion of timber in service. Furthermore, previous studies in poplar have shown that the proportion of reaction wood can vary from 7 to 40% depending on the clone (Badia et al, 2006).…”

“…The proportion of reaction wood is associated with environmental conditions experienced by the tree during its development (Badia et al, 2006). In the case of an environment characterised by the presence of strong wind, the tree will develop a tendency to produce reaction wood to change its centre of gravity so as to bring the stem to a vertical position (forming a curve).…”