Enter the total diameter of a tree at 4.5 feet off the ground into the calculator to determine the basal area.

## Basal Area Formula

The following formula is used to calculate the basal area of a tree.

BA = F * DBH^2 * N

- Where BA is the basal area
- F is the foresters constant (.005454)
- DBH is the average diameter of the tree at “breast height” which is 4.5 feet (in)
- N is the number of trees per acre.

## Basal Area Definition

Basal area is defined as the total area of an acre that is occupied by tree stems.

## Basal Area Example

How to calculate basal area?

**First, determine the average diameter of the trees at “breast height”.**For this example, we will say we measure 10 trees, and on average they have a diameter of 10 inches at breast height (4.5 feet).

**Next, measure the number of trees per acre.**After counting, we find the number of trees per acre to be 250.

**Finally, calculate the basal area.**Using the formula above, we find the basal area to be .005454*10^2*250 = 136.35 square feet per acre.

## FAQ

**What is basal area?**

A basal area is defined as the total area of an acre occupied by the tree stems.

**What is a foresters constant?**

The foresters constant described above is used to convert inches to square feet.