How do I Calculate Quadratic Mean Diameter?

How do I Calculate Quadratic Mean Diameter?
••• forest image by Dozet from

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.

    Press "(" on the calculator.

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

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

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

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

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

    Things You'll Need

    • Scientific calculator
    • Basal area per acre
    • Trees per acre


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

Related Articles

How to Calculate the Length of Cable on a Drum
How do I Calculate the Geometric Mean on an HP 12C?
How to Calculate the Geometric Mean
What Are the Units for Diameter?
Pine Tree Diameter Vs. Age
How to Calculate Volume of a Circular Cylinder
How to Find a Z Score
How to Calculate the Diameter of a Rectangle
How to Convert Taper to Degrees
How to Find the Area of Squares
How to Calculate the Volume of a Pipe
How to Find Standardized Values for Correlation
How to Find the Radius of a Circle
How to Calculate the Surface Area of a Circle
How to Convert Square Meters to Linear Yards
How to Calculate Square
How to Calculate the Grand Mean
How to Convert a Mean Score to a Percentage
How to Calculate Tree Basal Area
How to Calculate the Root MSE in ANOVA