Macroscopic conditions wood is composed of bark, xylem and pith.
Bark: all tissues wrapped around the outer side of the secondary xylem of the trunk, branches, and roots of wood;
Cambium: Located between the bark and xylem, the diameter of the wood becomes thicker due to the meristem function of the cambium;
Secondary xylem: located between the cambium and the medulla, derived from the division and growth of the cambium;
The pith core: generally in the middle of the trunk, wrapped by xylem, providing nutrients for the growth of young trees, with a short life cycle.
