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How to Tell How Old a Tree Is: A Brief Guide

Man trimming a tree

Knowing how to tell how old a tree is promotes several benefits. You can better understand the health and potential lifespan of a tree on your property, care for it adequately, and appreciate its history. Thankfully, you can tell the age of a tree through a few different methods, both of which are quick and easy for even the most novice tree hobbyist to complete. 

Beyond the Leaf Tree & Shrub Experts, a reliable tree service in Collegeville, PA, shares how to tell the age of a tree. 

Method One: Count the Rings

The traditional way to tell the age of old trees — and the method you’ve probably heard of — is to count the rings. Tree trunks have dark rings circling from the very center to the outer rim of the trunk. Each ring represents approximately one year of life.

When examining a tree trunk, you’ll see dark rings and lighter bands. One dark ring and one light band together equals one year. As such, counting the dark rings may be the simplest method for how to tell how old a tree is.

Of course, you can only use this method if you have access to the inside of the tree trunk — such as if you have already cut the tree down and can examine the tree stump. Certified arborists sometimes use this method by taking a core sample of the living tree to count the rings. But you shouldn’t do this unless you know the proper placement and technique to take the sample, as you don’t want to risk injuring the tree.

Method Two: Measure the Circumference

If you want to measure the age of a tree that is still living, the best way to do so is by measuring the circumference and then running that figure through a calculation.

Use a measuring tape to measure the distance all the way around the tree, which is the circumference. Be sure to wrap the tape measurer around the tree at least 4.5 feet off the ground to get an accurate measurement. 

Then, figure out the diameter of the tree based on your circumference. You can use this formula:

Diameter = Circumference / 3.14

For a tree with a 60-inch circumference, the diameter would be 19.1 inches.

Next, you’ll need to research the growth factor of your tree species. Different trees grow at different growth rates, but you can determine the growth factor with a simple Google search. For example, the growth factor of a Black Walnut is 4.5, while the rate for an Ironwood is 7. 

Simply multiply the diameter of your tree by the growth factor to determine its age. A Black Walnut with a diameter of 19.1 inches is approximately 85.95 years old. 

Contact Beyond the Leaf Tree & Shrub Experts for Professional Tree Care

Knowing how to tell how old a tree is is just one of the steps involved in maintaining healthy trees. For professional tree care in Collegeville, PA, contact Beyond the Leaf Tree & Shrub Experts today at (610) 978-6072.