Effects of drought acclimation on the mechanical properties of Ochroma pyramidale, Betula pendula and Acacia karroo tree seedling stems

摘要

Drought acclimation in woody plants tends to be associated with the development of denser vascular tissue. As wood density may be correlated with the mechanical properties of the tissue, we hypothesized that seedlings subjected to drought would develop stems that had a higher density as well as stiffer and stronger tissue. We tested our hypothesis on establishing trees of the species Betula pendula, Acacia karroo and Ochoma pyramidale. The seedlings were grown for 1 year under well-watered as compared with cyclically droughted conditions. The modulus of elasticity in bending, yield stress, density and pith- and bark fractions of the stems at different heights were measured.