Dendrochronology

Production of wood and bark begins in the cambium, a one cell thick layer beneath the inner bark. This remarkable layer of cells produces both the tissue destined to become the bark and the wood. The layer produced on exterior side of the cambium is called phloem or inner bark that contains sieve tubes that transport sugars and amino acids (synthesized in the leaves) downward to the roots. On the inner side, the cambium produces …

…units) fill spaces between cellulose chains and various size fibrils. The lignin is a phenolic compound (benzene with attached methoxy, propyl and hydroxy groups) which is tightly bound to the cellulose. In the production of paper in pulp mills, chemical removal of the lignin (the waste product and pollutant) leaves a water-cellulose fiber mixture which is dried and rolled in a series of heated cylinders which compresses the fibers together, forming a sheet of paper.