Enter the total girth of a tree and the growth rate into the calculator to determine the estimated age of the tree.

## Tree Age Formula

The following formula is used to estimate the age of a tree.

TA = G / GR

- Where TA is the tree age (years)
- G is the girth (diameter) at about 2-3 feet off the ground
- GR is the growth rate (growth factor) of the tree

## Tree Age Definition

**What is a tree age? **Tree age is the estimated amount of time that a tree has been alive. This can typically be estimated using the girth of a tree and its growth factor, also known as the growth rate.

## Example Problem

How to calculate tree age?

**First, measure the girth 2-3 feet above the ground.**For this example, the girth is measure to be 50cm.

**Next, determine the growth rate.**The average growth rate of the girth of a tree per year is around 2.5cm per year until it stops growing.

**Finally, calculate the age of the tree.**Using the formula, we find the tree to be 20 years old.

## FAQ

**How is tree age determined? **Tree age can be estimated using the formula above. The more accurate way of determining a tree age is through radioactive isotopes that are found in the tree itself.

**What is the maximum age of a tree? **The maximum age of a tree depends on the type of tree. The oldest trees in the world are the Great Basin Bristlecone Pine, and these can live to 5,000 years old or longer.

**Do rings show a trees age? **While rings in the trunk of a tree can be used to estimate a trees age, they do not provide an exact answer.