Calculating log volume using mid-point measurement involves using a cylinder with the same length as the log and with a diameter equal to the mid-point diameter of the log under bark. Mid-point measurement may be used on all tree species, regardless of diameter and length.

The formula for calculating the mid-point-measured volume is given by:

\[ V = \frac{\pi}{4} \cdot L \cdot D_{mi}^2 \cdot 10^{-8} \]

where:

- \( V \) is the log volume in m³sub
- \( L \) is the log length in cm
- \( D_{mi} \) is the mid-point diameter in mm

Let's assume the following values:

- Log Length: 500 cm
- Mid-Point Diameter: 30 mm

Using the formula:

\[ V = \frac{\pi}{4} \cdot 500 \cdot 30^2 \cdot 10^{-8} \]

Calculating step-by-step:

\[ 30^2 = 900 \]

\[ V = \frac{\pi}{4} \cdot 500 \cdot 900 \cdot 10^{-8} \]

\[ V \approx 3.1416 / 4 \cdot 500 \cdot 900 \cdot 10^{-8} \]

\[ V \approx 0.7854 \cdot 500 \cdot 900 \cdot 10^{-8} \]

\[ V \approx 353.43 \cdot 10^{-8} \approx 0.003534 \, \text{m}^3_{\text{sub}} \]

The calculated mid-point-measured volume is approximately 0.003534 m³sub.