The major noncarbohydrate, polypenolic structural constituent of wood and other native plant material that encrusts the cell walls and cements the cells together. It is a highly polymeric substance, with a complex, cross-linked, highly aromatic structure of molecular weight about 10,000 derived principally from coniferyl alcohol (C10H12O3) by extensive condensation polymerization. Higher heating value (oven dry basis): HHV=9111 BTU/LB (5062 CAL/G, 21178 J/G)[3].