I remember many years ago, I asked myself: how can I find out the height of a tree, without actually measuring it.

Somewhere around 2010, I think I found out a way to calculate the height of the tree, taking into account its shadow and the angle of the sun’s rays. Before I post the image, I will try to describe the entire process.

With the help of a stick, or anything else, whose length you know approximately, measure the length of the shadow. With the help of a stick or writing instrument (eg. pencil) determine the angle of the sun’s rays: tilt the stick in such a way that its shadow becomes a point.

The inclination of the stick and the shadow of the tree determine an angle: the angle between the sun’s rays and the shadow of the tree. I don’t know if it’s correct, but I’m going to post it anyway.

tan(α) = a/b; a = b · tan(α)

Where:

α – the angle between the shadow and the sun’s rays

a – the height of the tree

b – the shadow of the tree