The height, crown, and trunk of trees set them apart from shrubs and vines. Branches and leaves form the crown, or treetop. The trunk keeps the tree standing up, anchors the crown, and allows water and sap to move up and down the tree. It provides homes for animals and becomes lumber for people's houses.
People use wood for making toilet paper, pencils, and other things.
Roots keep the tree from falling over. They also gather water and nutrients from the soil. A root can be thinner than a strand of hair or more than a foot wide. Ninety-nine percent of a tree's roots grow within three feet of the soil surface. The distance the roots spread out from the trunk can equal twice the height of the tree.