This lecture covers the mechanical properties of wood, including density variations, microfibril angle, compression wood, standard wood testing methods like bending, compression, tension, and hardness tests, modulus of elasticity, modulus of rupture, stress/strain graphs, elasticity and rupture, failure at the microscopical level, types of failure in bending, wood as a viscoelastic material, effect of stress beyond proportional limit, compression test calculations, cell deformation under compression, micro cracks under compression, and the influence of moisture on wood mechanical properties.