Taking a Look at Wood
Knots are simply branches that the tree has either grown over or grown around.
We learned in "How a Tree Grows" that trees grow outward as well as upward. When they get bigger around, the tree has to grow either around or completely over a branch. The overgrown branch becomes the knot!
Take a look at the picture on the right. Can you see that when this piece of wood was part of a tree it had a branch growing out where the knot is? You can click on the picture to take a closer look.
Knots make whole pieces of wood weaker. So, wood with knots usually isn't as valuable! It's important to know how knots effect the properties of wood when making wood products. We will learn more about wood products in a later lesson.