The measurements required for estimating tree height vary depending on the tree’s location relative to you.

This case is the simplest as we only need to account for the change in height since the viewpoint (e.g., your eyes) is above the ground. The formula is:

tree height = tan(β) * distance from the tree + eye height,

where β is the angle between your eyes and the top of the tree.

Remember that the height of your eyes is not equal to how tall you are. If you do not know this value and can’t measure it, you can take α to be the angle between your eyes and the tree’s base. Then

eye height = tan(α) * distance from the tree.

• Below the viewpoint