Fig. 1

Bending treatments. a Asymmetrical bending treatments. b Symmetrical bending treatments. c Principle of stem bending: the stem is bent on a plastic constant-curvature template that imposes a pure bending. D_// is the diameter of the stem in the direction of the bending treatment, ρ is the radius of curvature of the template, L₀ is the initial length of the “bent segment”, namely 40 cm, and ε_max is the maximal strain applied to the stem bark