The holly tree (Ilex opaca) is an evergreen featuring bright-red fruits and small, greenish-white flowers. Often it is used in landscaping and for holiday decoration. It is hardy in U.S. Department of Agriculture plant hardiness zones 5 through 9 and may grow as tall as 50 feet. Because a holly tree often is pruned as a hedge, its height is not useful when calculating its age. Trunk circumference is the preferred method for measuring the age of a holly tree without harming it.
Place a tape measure at the base of the holly tree's trunk, and measure up 4 1/2 feet. Draw a line on the trunk with chalk to mark that spot.
Wrap the tape measure around the tree's trunk at the chalk mark, and measure the trunk's circumference in inches.
Type the trunk's inch circumference into a calculator. Multiply that number by 2.54 to convert the circumference measurement to centimeters.
Divide the centimeter total by 1.25. A holly tree's circumference grows at a rate of about 1.25 centimeters per year. So this final number represents the tree's approximate age in years.
Things You Will Need
- Tape measure
- Avoid using the tree borer method to measure a holly tree's age. In that method, a borer is inserted into the trunk to remove a core sample of the tree in order to count the annual growth rings. That method is accurate, but it harms the tree and may diminish its lifespan.
- Arbor Day Foundation: Holly, American
- Oare Gunpowder Works Country Park: How to Find Out the Age of a Tree
- U.S. Department of Agriculture, Natural Resources Conservation Service: Plant Fact Sheet -- American Holly
- Catch the Science Bug: Measuring the Age of Trees
- Athens-Clarke County, Georgia, Community Tree Program: How Old Is My Tree?
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