How to Tell the Age of a Tree Without Cutting it Down

Overview

Scientists who specialize in dendrochonology study the rings inside the trunks of trees to determine a tree's age. As trees grow in height and width, they develop growth rings in the new layer of wood -- one ring for each year of growth. If you can't cut down a tree and study the cross section to count these rings, you can still determine the tree's age without having to get out the chainsaw.

Step 1

Determine the correct species of the tree. Tree species have different growth factors, which will affect your calculations.

Step 2

Wrap the tape measure around the tree's trunk about four and one-half feet above the ground to measure the tree's circumference in feet. Multiply the tree's circumference by 3.14. The result will be the tree trunk's diameter.

Step 3

Multiply the tree trunk's diameter by the tree species' growth factor to calculate the tree's age. The growth factors for the most common tree species are: cottonwood and aspen (2.0); silver maple, pin oak, Linden or Basswood (3.0); river birch (3.5); green ash, red oak and American elm (4.0); red maple or black walnut (4.5); sugar maple, white birch, black cherry and white oak (5.0); ironwood, dogwood and redbud (7.0); and shagbark hickory (7.5).