The cell wall of wood fibres is composed of layers that have a specific structure and play different roles in the mechanical properties of wood at the macroscopic scale (e.g., tree rings). The variability of the cells distribution, thickness or properties leads to difficulties in the interpretation of complex wood behaviour at the macroscopic scale (mechanosorption, growth stress generation, etc.). The measurement of the mechanical behaviour of each layer, and/or layer components, must help us to overcome some of these difficulties and achieve a better understanding about the origin of wood properties.