Answer
Pull the tire to the side, release it, measure the period of oscillation T, and then calculate L, which is the distance from the center of the tire to the branch.
Add the distance from the tire center to the ground, and that is the branch height.
Work Step by Step
Approximate the swing as a pendulum. Equation 11–11a tells us that the period of a pendulum of length L depends on the square root of its length, $T=2 \pi \sqrt{\frac{L}{g}}$.
