We can calculate the age of the white oak if we know its circumference and growth factor. The circumference of a white oak has to be 100 feet for it to be 159 years old. But that is only for a white oak. Other trees grow at different rates.
Here's how to do the tree age math:
- Using a tape measure, find the circumference of the tree (starting four feet off the ground).
- Divide the circumference by 3.14 (pi) to find the diameter.
- Now multiply the growth factor by the diameter.
Here are growth factor rates for some common trees:
- 2.0: Aspen, Cottonwood
- 3.0: Silver Maple, Pin Oak, Linden
- 3.5: River Birch
- 4.0: American Elm, Green Ash, Red Oak
- 4.5: Black Walnut, Red Maple
- 5.0: Sugar Maple, White Birch, White Oak, Black Cherry
- 7.0: Dogwood, Ironwood, Redbud
In the case of the white oak, the circumference was 100 feet divided by 3.14 (pi). That equals 31.84. Now, multiply by the growth factor of 5. You come up with 159.23 years old. It was a small tree when the North and the South fought the Civil War and it lived through the emergence of cars, planes, power lines, and greatly expanded farming.