A tree is a tall plant with a trunk and branches made of wood. Trees can live for many years. The oldest tree ever discovered is approximately 5,000 years old and the oldest tree from the UK is about 1,000. The four main parts of a tree are the roots, the trunk, the branches, and the leaves.
The roots of a tree are usually under the ground. However, this is not always true. The roots of the mangrove tree are often under water. A single tree has many roots. The roots carry nutrients and water from the ground through the trunk and branches to the leaves of the tree. They can also breathe in air. Sometimes, roots are specialized into aerial roots, which can also provide support, as is the case with the banyan tree.
The trunk is the main body of the tree. The trunk is covered with bark which protects it from damage. Branches grow from the trunk. They spread out so that the leaves can get more sunlight.
What is a Tree?
Trees, shrubs, and vines belong to many different plant families. Some are closely related, like ponderosa pine and limber pine. Others are not closely related at all, like eastern redcedar and silver maple. However, trees, shrubs, and vines all have one thing that separates them from the rest of the plant world: a woody stem that is perennial or that lives for many years. Grasses and certain other plants may be perennial, but their tops are regrown year after year from rhizomes, bulbs, or other organs found at or just under the soil surface.
Let’s look at each of the parts of a woody plant’s stem and see how they are put together and how they grow larger year after year. If you could tunnel into a woody plant’s stem, whether the trunk of a tree or a twig on a shrub, you would first encounter bark, then cambium, and finally wood or xylem. Bark is the outer covering on the trunk, twigs, and woody roots. The outer bark we are familiar with is a layer of dead corky cells protecting the rest of the stem. The inner bark, or phloem, is a live spongy layer just inside the outer bark that moves sugars and other substances from the leaves to the stem, roots, and other places where they are needed. Inner bark eventually grows out to form part of the outer bark.
In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves.