Cabinets can be made from all sorts of materials, but one of the most popular is wood. Trees such as oak, mahogany, alder and pine are popular choices for making cabinets.
You are an apprentice cabinetmaker. You wonder why wood is one of the better construction materials. Your boss tells you to start by learning about the tree itself. "I'll bet you didn't know that a tree is more dead than alive," he says.
You are puzzled. How can this be? Read the following excerpt to learn more about tree biology.
Peel away the layers of a tree to see its components. First you will see the outer bark, composed of dead cells, which protects the tree from all types of injuries and from burrowing insects. It also insulates the tree against extreme cold and hot
The inner bark, called phloem, is like a pipeline that carries food produced in the leaves down to the trunk and to the roots. Interestingly, the phloem only lives for a short time, and then dies to become a part of the outer bark.
Inside the inner bark is the cambium cell layer, which is the only growing part of the trunk. Each year, the cambium produces new inner bark on the outside, and on the inside produces new sapwood. Sapwood carries water and minerals from the roots
up the tree. As new outside layers of sapwood are added, the inside layers die. The dead inside layers are called the heartwood. The heartwood, even though it is dead, gives the tree its strength.
You jotted down some questions as you read the article. Can you answer them?
- What is the function of the outer bark?
- What happens to the phloem after it dies?
- What layer gives the tree its strength?