How can we find out how old a tree is? - Presentation

Determining the age of a tree is a fascinating process that combines observation, measurement, and a bit of mathematics. Educators aim to make children aware that trees can be ancient living entities and that there are methods to estimate their age. One simple approach involves measuring the circumference of a tree at its thickest point, roughly one metre above the ground. The measurement in inches is a rough estimate of the tree's age in years. This activity can provoke thought and comparison, encouraging children to consider whether the tree is as old as themselves, their parents, or even their grandparents.

For a more accurate age determination, counting the number of rings on a cross-section of the tree's trunk is a reliable method, as each ring typically represents one year of growth. However, this method requires the tree to be cut down, which is not ideal. An alternative, non-destructive method involves measuring the tree's circumference and then dividing by a factor based on the tree's growing conditions: by 1.25 for woodland trees and by 2.5 for trees in open spaces. This calculation can help estimate the tree's age in years. For example, if a tree in an open space has a circumference of 115 cm, dividing by 2.5 gives an estimated age of 46 years. Children can apply this method to various trees in their school grounds or at home, comparing their ages and understanding the longevity of these natural giants.