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Estimating the age of a Tree.

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Determining Tree Size - Diameter at breast height, or DBH, is the standard for measuring trees. DBH refers to the tree diameter measured at 4½ feet above the ground.  If the tree has a branch or a bump at 4½ feet, it is better to measure the diameter slightly below or above the branch/bump.

  1. With a measuring tape, measure 4½ feet up the trunk of the tree from the ground. Use a thumb tack to mark the height on the tree.

  2. Wrap your string around the tree trunk at 4½ feet. Make sure the string is straight and tight around the trunk, and mark or cut the circumference on the string.

  3. Measure the length of string to get the circumference of the tree.

  4. Convert the circumference measurement to diameter by dividing the circumference by pi (3.14).

Determining Tree Age - Multiply the diameter of your tree (that you determined above) by the growth factor of your particular species of tree in the chart below. This will tell you the approximate age of your tree. (For instance, if you have a white oak with a diameter of 22 inches, you would multiply that by the growth factor of 5 to determine your tree is approximately 110 years old.) 

heritage tree measuring_tree.jpg

Growth Factors by Tree Species

  • Red Maple Species - 4.5 Growth Factor X diameter

  • Silver Maple Species - 3.0 Growth Factor X diameter

  • Sugar Maple Species - 5.0 Growth Factor X diameter

  • River Birch Species - 3.5 Growth Factor X diameter

  • White Birch Species - 5.0 Growth Factor X diameter

  • Shagbark Hickory Species - 7.5 Growth Factor X diameter

  • Green Ash Species - 4.0 Growth Factor X diameter

  • Black Walnut Species - 4.5 Growth Factor X diameter

  • Black Cherry Species - 5.0 Growth Factor X diameter

  • Red Oak Species - 4.0 Growth Factor X diameter

  • White Oak Species - 5.0 Growth Factor X diameter

  • Pin Oak Species - 3.0 Growth Factor X diameter

  • Basswood Species - 3.0 Growth Factor X diameter

  • American Elm Species - 4.0 Growth Factor X diameter

  • Ironwood Species - 7.0 Growth Factor X diameter

  • Cottonwood Species - 2.0 Growth Factor X diameter

  • Redbud Species - 7.0 Growth Factor

  • Dogwood Species - 7.0 Growth Factor X diameter

  • Aspen Species - 2.0 Growth Factor X diameter

 

Click here for help identifying your tree.

Thanks to Roberta Urbani  for compiling this information. 

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