Work out tree age from girth instantly with clear inputs, formula shown and shareable results.
Converts circumference to diameter and applies the species growth factor used in the standard arboricultural age tables.
Growth factor method
Diameter = circumference / pi; age (years) = diameter in inches x species growth factor
Within roughly 20% for open-grown trees; crowded or stressed trees grow far more slowly than the factor assumes.
At breast height, 1.3 to 1.4 metres above ground on the uphill side of the trunk.