How old is an oak tree with an 8 foot circumference?

Landscape & Site WorkDendrochronology Estimation

Oak Tree Age Calculator (ISA Growth Factor)

Estimate the age of native oak trees without damaging or coring the trunk based on trunk circumference and International Society of Arboriculture (ISA) growth factors.

Landscape & Site Work Field StandardsDendrochronology Estimation

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Quick Summary & Key Answer

To estimate an oak tree's age: calculate its Diameter at Breast Height (circumference divided by 3.14159), then multiply by the species growth factor (5.0 for White Oak, 4.0 for Red Oak, 3.0 for Pin Oak). A White Oak with a 60-inch circumference has a 19.1-inch DBH, making it roughly 95 years old.

White Oaks can live over 400 to 600 years in undisturbed conditions.
The ISA Growth Factor formula accurately estimates age without invasive core drilling.
A 36-inch diameter White Oak was likely growing during the American Civil War.

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Trunk Circumference at 4.5 ft (Breast Height)inches

inches

Oak Tree Species

Calculated OutputISA Age Estimated

Estimated Oak Tree Age

95 Yearsyears old

Trunk Diameter (DBH): 19.1" (48.5 cm)
Growth Factor Applied: 5.0
Estimated Planting Era: Circa 1931

Note: Trees growing in open yards grow faster than forest-competed trees. Trees with adequate moisture develop wider annual growth rings.

Oak Species Growth Factors

White oaks grow slower and develop denser heartwood than fast-growing red or pin oaks.

Frequently Asked Questions

Common questions regarding this calculation and code compliance

An 8-foot (96-inch) circumference White Oak has a 30.5-inch diameter and is approximately 150 to 160 years old.