Estimate the age of a tree by its trunk circumference and species! Enter your measurements to find out how old a tree might be.
Estimated ages (years) for common tree species based on trunk circumference (inches).
| Circumference | Oak (Ã4.0) | Maple (Ã4.5) | Pine (Ã5.0) | Birch (Ã5.0) | Beech (Ã4.0) |
|---|---|---|---|---|---|
| 12" | 48 | 54 | 60 | 60 | 48 |
| 24" | 96 | 108 | 120 | 120 | 96 |
| 36" | 144 | 162 | 180 | 180 | 144 |
| 48" | 192 | 216 | 240 | 240 | 192 |
| 60" | 240 | 270 | 300 | 300 | 240 |
| 72" | 288 | 324 | 360 | 360 | 288 |
| 84" | 336 | 378 | 420 | 420 | 336 |
| 96" | 384 | 432 | 480 | 480 | 384 |
| 120" | 480 | 540 | 600 | 600 | 480 |
| 144" | 576 | 648 | 720 | 720 | 576 |
| 180" | 720 | 810 | 900 | 900 | 720 |
| 240" | 960 | 1080 | 1200 | 1200 | 960 |
| 300" | 1200 | 1350 | 1500 | 1500 | 1200 |
Measure the trunk at chest height (about 4.5 feet / 54 inches above ground). Use a flexible measuring tape to get the circumference in inches â this is the distance around the trunk.
Different tree species grow at different rates. Fast growers like Willow (Ã3.0) add girth quickly, while slow growers like Sequoia (Ã8.0) take much longer to reach the same circumference. Multiply circumference by the factor to estimate age.
Growth rates vary based on soil quality, sunlight, water availability, climate, and competition. The Âą20% range accounts for these natural variations, giving you a realistic age window rather than a single number.
Dendrochronology is the scientific method of dating tree rings (also called growth rings). Each ring typically represents one year of growth. Counting rings gives the most accurate age, but circumference estimation is a useful non-invasive alternative.
The oldest known tree is a Great Basin bristlecone pine called Methuselah, over 4,800 years old. General Sherman, a giant sequoia, is about 2,200 years old. These ancient trees remind us of the incredible longevity of nature.
Knowing a tree's age helps assess its ecological value, plan conservation efforts, estimate carbon sequestration, and appreciate the natural history of your landscape. Older trees support more biodiversity and store more carbon.