# How Do I Calculate Quadratic Mean Diameter?

Calculating quadratic mean diameter, a conventional measure of the average tree diameter in a stand, requires estimates of the stand's basal area per acre and trees per acre. Basal area per acre, a measure of the stand's stock, consists of the average of the sum of the cross-sectional area of all of the trees taken at 4 1/2 feet above ground level.

### Step 1

Press "(" on the calculator.

### Step 2

Press "(" again then enter the basal area per acre figure.

### Step 3

Press "/" then the trees per acre figure followed by ")."

### Step 4

Press "/" again and enter "0.005454." Press ")."

### Step 5

Press the "x to the power of y" key, an italic "x" with "y" in superscript above it.

### Step 6

Enter "0.5" and press the equals button. The display will show the quadratic mean diameter in inches, the traditional measurement used.

### Things Needed

- Scientific calculator
- Basal area per acre
- Trees per acre

### TL;DR (Too Long; Didn't Read)

Quadratic mean diameter equals ( [BAPA/TPA] / 0.005454) to the power of 0.5.

### Cite This Article

#### MLA

Butler, Michael. "How Do I Calculate Quadratic Mean Diameter?" *sciencing.com*, https://www.sciencing.com/do-calculate-quadratic-mean-diameter-6893917/. 22 November 2019.

#### APA

Butler, Michael. (2019, November 22). How Do I Calculate Quadratic Mean Diameter?. *sciencing.com*. Retrieved from https://www.sciencing.com/do-calculate-quadratic-mean-diameter-6893917/

#### Chicago

Butler, Michael. How Do I Calculate Quadratic Mean Diameter? last modified March 24, 2022. https://www.sciencing.com/do-calculate-quadratic-mean-diameter-6893917/