Le prix du meilleur poster AnaEE France 2018 a été remis lors de la Conférence d’Ecologie Fonctionnelle (Nancy, décembre 2018), à l’équipe de Jana DLOUHA, Thiéry CONSTANT, François NINGRE, Vivien BONNESOEUR, Bruno MOULIA et Meriem FOURNIER pour leur présentation sur la résistance biomécanique au vent d’une hêtraie (résumé en anglais).
Wind sensing and thigmomorphogenetic enhancement of secondary growth as a major contributor to the biomechanical resistance to wind in a beech forest.
Jana DLOUHA1, Thiéry CONSTANT1, François NINGRE1, Vivien BONNESOEUR1, Bruno MOULIA2, Meriem FOURNIER1
1Université de Lorraine, AgroParisTech, INRA, UMR Silva, F-54000 Nancy, France
2Université Clermont Auvergne, INRA, PIAF, F-63000 Clermont-Ferrand, France
The mechanism responsible for acclimation of trees to mechanical cues induced by wind is called thigmomorphogenesis. Stimulations perceived by trees as a result of swaying are the longitudinal strains - elongation or compression - of wood living cells. In reaction to these stimuli, a tree modulates the spatial distribution of wood biomass to secure itself against the wind load by increasing its diameter growth to boost its stem resistance to breakage, by limiting its height growth to reduce the wind load, and, by developing its root system to improve its anchorage.
In this study, we investigate the effect of thinning on radial growth of beech poles on a sample of forty trees submitted to four treatments: control free and guyed trees and thinned free and guyed trees. The aim was to separate the effect of increased availability of resources (light, nutrients etc.) from the thigmomorphogenetic effect. Results show that the contribution of wind load to increased radial growth after thinning ranged between 40 to 70% depending on the year climatic conditions. Similar difference is observed between control trees free to sway and guyed showing that the intensity of thigmomorphogenetic response does not depend on the growth potential. Further investigations are necessary to understand differences between species in order to better evaluate their acclimation potential to predicted climatic changes.