Nowadays, the design of composite materials considering sustainability and the environmental impact of the production is conspicuous. Therefore, in this work, we focus on investigating the mechanical behaviour and structure of a new green wood-based fibrous composite material bonded with a novel polymer matrix. The constitutive prediction models employing the material and structure design approaches simultaneously are proposed here to describe the material's microstructure. The goal is speeding up trials and reducing experiments expenses by replacing tests with computer simulations. Additionally, the relationship between material behaviour and structure is established and will be later used to generate Representative Volume Elements (RVEs) for finite element analysis (FEA).