Eco-Activity: Learn How To Identify a Tree’s Age!


Trees are simply magnificent and carry a lot of wisdom within their layers of wood. If you think about it, many old trees have lived through very significant events and phenomena that have been experienced on Earth. Trees in many cases outlive people, remaining firmly rooted in place for long periods of time; sometimes even centuries. The oldest known tree is over 5,000 years old! This tree is a bristlecone pine living in the White Mountains of California, in the United States. This tree is truly spectacular, and even has a name – Methuselah!

For today’s eco-activity, learn how you can identify a tree’s age! Check out these three tips for cracking the code.

1) Count the rings

Can you see the top of the stump, or if you find a spot where the branch has been sawed off? If so, look closely and start counting! As trees grow, they add a new layer of wood below the bark (normally a new ring will be added each year of a tree’s life). Each layer (known as a ring) may come in a different width. Several factors such as access to nutrients, water, attacks from insects and fungi, and damage from fire can affect how much a tree grows each year. How many tree rings do you see?

2) Measure the circumference

You can also measure the circumference (the distance around the outside of a circle) of the tree to estimate its age! With a rope, wrap it around the trunk of the tree. Mark off the spot where the rope encircles the tree; measure it beside a ruler or measuring tape. As an approximation, a tree grows about 2.5cm a year, so you can make your guess from there!

3) Count the whorls 

A whorl is a cluster of branches that arrange themselves in a circular fashion, often wrapping around the stem of a tree or plant. Many species, like pines, spruces and firs, will grow a whorl of branches annually. If you count the number of whorls of branches, you should be able to guess how old the tree is! Check out the photo and diagram below for help.


    • In old growth forests a tree can be 100 years old and still look like a sapling. (I discovered that in the book Hidden Life of Trees. I really like that book. It isn’t directly a kids book but if you can understand the language that’s about the only thing that makes it not a kids book. There’s also 2 other books called Secret Wisdom of Nature; which is about how everything relies on each other in nature, and Inner Life of Animals that I also like).

    • In commercial forests most trees are harvested when they are only a centre old. If trees live to 2 thousand (which I think is accurate) and people live to 100 years (which I think the number is more like 80 but 100 is easier to turn into a presentation) that would mean it would be like letting a child live to age 5.