🌳 Tree Age Calculator
Approximate tree age without coring by applying growth factors to trunk circumference measurements.
How to Use This Calculator
Measure circumference
Wrap a tape at 4.5 ft height (DBH) and record circumference.
Select species factor
Growth factors represent average annual growth for common species.
Adjust for site conditions
Use custom factors for exceptional growth rates or slow sites.
Formula
Age ≈ Circumference (in) ÷ Growth Factor
Growth factors are empirical averages. Accurate ages require increment borers and ring counts.
Full Description
Tree age estimates based on circumference provide quick insights for urban forestry, landscape planning, and educational purposes when coring is impractical.
Combine circumference-based estimates with site observations and growth records to refine the age range, especially for stressed or open-grown trees.
Frequently Asked Questions
How accurate is this method?
Expect ±20% error. Growth factors vary by site quality, competition, and species genetics.
Why use circumference instead of diameter?
Circumference is easy to measure; dividing by π yields diameter if needed.
Can I estimate conifer age?
Yes—use a conifer-specific growth factor sourced from forestry references.
What if the tree has multiple stems?
Measure the largest stem or calculate quadratic mean diameter for multi-stemmed specimens.