Eco-Activity #149: Learn How To Identify a Tree’s Age!

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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.

22 COMMENTS

  1. That tree in the US is amazing! When we found a tree stump in the forest, dad told me to count the rings. I thought he meant the three different parts of the stump (there were sections of colours) but then I realized what he actually meant – I didn’t know it was that common for a tree to get so so old! Thanks, Wild Wire!

  2. My mom, dad and brother went and cut down a dead tree and when we cut it up back at our cabin we found the rings.