Bark (tree) – the outside covering of the stems and roots of trees and woody plants; protects from external threats, rids the tree of wastes by absorbing and locking them into its dead cells and resins, and includes phloem which transports large quantities of nutrients throughout the plant

Branch (tree) – secondary woody stem or limb connected to, but not a part of the central trunk of a tree or shrub; large branches are called boughs and small branches are know as twigs

Cambium – a thin layer between the xylem and phloem of plants

Heartwood – older, inactive central wood of a tree or woody plant which is usually darker and denser than the surrounding sapwood

Leaves – any of the usually flat, green, above-the-ground parts that grow in various shapes from the stems or branches of plants and trees 

Phloem – the living tissue in vascular plants that carries nutrients, particularly sucrose, to all parts of the plant

Roots – underground portion of a plant that lacks buds, leaves or nodes and serves as support, draws minerals and water from the surrounding soil and sometimes stores food; also an underground stem such as a rhizome, corm or tuber

Sapwood – the outer portion of wood that lies between the cambium and heartwood

Tree – a perennial woody plant having a main trunk and usually a distinct crown

Trunk (tree) – the thick, central woody stem of a tree

Xylem – complex tissue found in vascular plants