Tree Diameter Calculator

To calculate Tree Diameter, input either Tree Circumference or use Shadow Method measurements. For Circumference Method, measure around the tree trunk at Breast Height (4.5 feet or 1.37 meters).

For Shadow Method, input Tree’s Shadow Length, Object Height, and Object’s Shadow Length. Click Calculate to view the Tree Diameter and Cross-sectional Area.

How to measure Diameter of tree?

To measure Tree Diameter, use one of several proven methods. The most common is Circumference Method, where you measure tree’s circumference at Breast Height (DBH) and divide by π (3.14159).

Alternative methods include using a Diameter Tape, Biltmore Stick, or Shadow Method. For Shadow Method, measure a vertical object’s height and shadow length, then measure tree’s shadow length to calculate diameter using proportional relationships.

Formula for Tree Diameter

Circumference Method:

Diameter = Circumference ÷ π
where:
Circumference = Tree circumference at breast height (4.5 feet)
π = 3.14159

Shadow Method:

Tree Height = (Tree Shadow Length × Reference Height) ÷ Reference Shadow Length
where:
Tree Shadow Length = Length of tree shadow
Reference Height = Height of vertical reference object
Reference Shadow Length = Length of reference object shadow

Cross-sectional Area:

Area = π × (Diameter ÷ 2)²
where:
Diameter = Tree diameter in consistent units
π = 3.14159

Example 1: Using Circumference

• Measurement Method = Circumference
• Circumference = 94 inches
• Calculated Diameter = 29.9 inches
• Cross-sectional Area = 702.9 square inches
• Measurement Height = 4.5 feet

Example 2: Using Shadow Method

• Measurement Method = Shadow
• Tree Shadow = 25 feet
• Reference Object Height = 6 feet
• Reference Shadow = 4 feet
• Calculated Diameter = 37.5 inches

Example 3: Large Oak Tree

• Measurement Method = Circumference
• Circumference = 157 inches
• Calculated Diameter = 50 inches
• Cross-sectional Area = 1,963.5 square inches
• Tree Type = Mature Oak

Example 4: Young Pine Tree

• Measurement Method = Circumference
• Circumference = 31.4 inches
• Calculated Diameter = 10 inches
• Cross-sectional Area = 78.5 square inches
• Tree Type = Young Pine

Example 5: Using Biltmore Stick

• Measurement Method = Direct Diameter
• Measured Diameter = 15 inches
• Cross-sectional Area = 176.7 square inches
• Measurement Tool = Biltmore Stick

What is Tree Diameter?

Tree Diameter is a Forest Measurement that represents width of a tree trunk at Breast Height (DBH), typically measured at 4.5 feet (1.37 meters) above ground level. This measurement is crucial for calculating Tree Volume, estimating Tree Age, planning Forest Management, and assessing Tree Health. DBH (Diameter at Breast Height) is the standard measurement used by Foresters and Arborists to monitor Tree Growth, determine Timber Value, and make Forest Management decisions.