Basal area

Okay buddy, have you ever looked at a tree and noticed that the trunk of the tree is bigger at the bottom than it is at the top? Well, that's because the tree needs a wider base to hold it up.

Now, imagine drawing a circle around the base of the tree trunk on the ground. This circle tells you how much space the tree takes up on the ground. This is called the basal area.

Scientists use basal area to help them see how many trees or how much forest is in an area. They measure the basal area by calculating the size of all the tree trunks in a particular area, by drawing a circle around each tree and adding up all the circles.

So, the bigger the basal area, the more trees or the bigger the forest in that area. Pretty cool, right?