Trees have three main parts - the leaves, the trunk and the roots. The upper part of the tree with the branches is called the crown . Needles or leaves are the part of the tree that make sugar from air and water. They do this by a chemical process called photosynthesis in which energy from the sun, carbon dioxide from the air, and water recombine to form sugars and oxygen.
Stomates are tiny holes that control the amount of air that enters and leaves the tree.
Chlorophyll is a chemical that makes leaves green. It is found inside the plant's cells where chloroplasts absorb the sun's energy for photosynthesis. The trunk has several layers. The outer bark protects the tree from fire or insects and insulates it from extreme heat and cold. The phloem is the layer of cells that forms a pipeline to carry sugars from the leaves to the rest of the tree.