Intratree Variation in Viscoelastic Properties of Cell Walls of Masson Pine (Pinus Massoniana Lamb)

In this study, Pinus massoniana Lamb at different heights, across the annual rings, and between earlywood and latewood was measured by X-ray diffraction and the chemical composition was analyzed by chemical treatment. Results indicated that the microfibril angle (MFA) decreased and the chemical composition changed little with the increase in height from 1 m to 9 m. In the radial direction, the MFA decreased and the chemical composition changed little with an increase in annual rings. The cellulose content of latewood was higher than that of earlywood. The viscoelastic changes of wood cell walls at different heights, across the annual rings by the method of quasi-static nanoindentation and dynamic modulus mapping techniques. Results indicated that the wood cell walls' elastic modulus increased, and the creep rate and creep compliance decreased with the increase in height; The elastic modulus and hardness increased with the annual rings. The cell walls' storage modulus increased and the loss modulus gradually decreased with an increase in height; the storage modulus gradually increased and the loss modulus decreased with the annual rings.