Wooden base of arboreal plants. Its transversal section is formed by diverse patterns positioned in concentric bands that indicate the various stages of the growth of the tree and that essentially present the following succession (from inside out): medulla, heart-wood, sap-wood, cambium, liber and bark. The study of this structure and of its characteristics (in particular of anisotropy), as the knowledge of various types of cuts practiced for the realization of boards, is fundamental for understanding the behavior and the deterioration of wood, that is for the conservation of works in wood, and among these, panel paintings.