No matter how much space and light are available, radial growth distribution in Fagus sylvatica L. trees is under strong biomechanical control

Abstract Key message This study presents the first attempt to quantify how thigmomorphogenetic syndrome is involved in Fagus sylvatica L. tree growth responses thinning. An experimental design preventing mechanosensing half of trees demonstrated that radial distribution roots and along stem under strong biomechanical control. Context Studies on mechanosensitive control real forest conditions are rare those existing date all deal with conifer species. In current context global changes, it important disentangle different biotic abiotic factors affect growth. Aims Whereas changes after thinning usually interpreted as decreased competition for resources, this investigates importance controls inside tree. Methods an even-aged beech stand, 40 pole-sized (size class at thinning) were selected, plot was thinned and, within each sub-plot (thinned unthinned), guy-wired order remove mechanical stimulations lower part stem. Four years later, felled volume increment, ring width height, largest structural measured. The effect stimulation two treatments unthinned) assessed. Results Removal increment well root but did not axial When strain removed, height changed drastically ice-cream cone-like distribution, indicating a shape. Conclusion allocation Mechanical explain more than 50% stimulated by thinning, whatever indicator. A further challenge better understand cambial cells perceive strains during integrate into process-based tree-growth modeling.