The goal of this work, in the scientific and mathematic contest, is to find out the age of a tree, without cutting it.

At first, a tree has to be taken in examination. There are several methods to approach this situation but only two of them are illustrated here.

Both of them imply the measure of the circumference of the tree. It can easily be estimated winding the tree with a folding metre at a high of 1.5 metres from the ground.

The first method involves to divide this value to 2.5, which is the medium growth factor of a tree.

The second implies the cutting of a part of a branch: its rings and its circumference have to be measured and then you can use a proportion to determinate the number of the rings of the whole tree (that's the age).

This will be an approximately result because the exact one can only be found counting the rings of the whole tree.