The chemical interactions between wood components i.e., cellulose, hemicelluloses and lignin are of fundamental importance for understanding the chemical aspects of wood formation and its reactivity during fibre processing. Triggered by environmental concerns and oil dependence, there is consensus to find alternative sources of energy, fuel and platform chemicals from a renewable resource. The use of lignocellulosic material as a raw material to meet these demands is being pursued, and a broad potential base has been identified. However, progress will greatly depend on detailed knowledge of how the fibre elements interact with one another in the lignocellulosic material. The present work provides new insights into these interactions, more specifically, covalent bonds between lignin and carbohydrates, normally reffered to as lignin carbohydrate complexes (LCC), and how structural differences between them affect their reactivity. Based on the study, a new ultrastructural model of the fiber wall is presented.