A tree is a plant. Trees are perennial plants that use photosynthesis to make their own food like other plants. They have woody stems and trunks and tend to live for many years.
To be considered a tree, a plant should have at least one erect, perennial stem that is at least 3 inches in diameter at a point 4.5 feet above the ground with a crown of foliage. The mature height should be at least 13 feet. Plants that are not tall enough to be trees are often called shrubs. Trees are secured into the ground by roots. This root system pulls water and nutrients from the ground for the tree to use. Trees are classified as deciduous or evergreen. Trees that lose their leaves in the fall are deciduous, while evergreen trees keep their leaves and remain green throughout the year.