The tensile strength of isolated wood rays of beech (Fagus sylvatica L.) and its significance for the biomechanics of living trees

Wood rays of beech trees were isolated with the aid of a new kind of milling technique, and their strength was directly measured using microtensile testing. The unexpectedly high tensile strength of approximately 75 MPa in dry conditions leads to the supposition that, besides the known physiological functions of substance storage and conduction, the ray parenchyma also makes a contribution to the biomechanics of living trees which has been previously underestimated.