Tree

A tree is a tall plant with woody tissue that regularly renews its growth. Trees are important for the existence and diversity of life on Earth and are classified based on visual criteria[1]. Although there is no scientific definition to separate trees and shrubs, a useful definition for a tree is a woody plant having one erect perennial stem (trunk) at least three inches in diameter.

The following are the parts of a tree:
 * Leaves: broadleaf or needles; primary location for photosynthesis and producing hormones and other chemicals.
 * Twigs and Branches: support structures for leaves, flowers, and fruits.
 * Crown: the upper part of the tree composed of leaves, twigs, branches, flowers, and fruit.
 * Flowers: the site of reproduction. Trees can be male, female, or both. Conifers, however, do not have petals and typical flower structures.
 * Fruits and Seeds: all trees have seeds. Most are inside of the fruit.
 * Trunk: generally a single “stem,” but can be multiple-stemmed. The main functions include supporting the crown, transporting water and nutrients, and storing food.

The outside layers of the tree trunk are the living portion, and the cambium produces new wood and new bark.