DBH (Diameter at Breast Height) Converter

DBH (Diameter at Breast Height) Converter

Convert tree trunk diameter measurements used in forestry

Input DBH Value

Please enter a valid positive number.

Tree Size Comparison (Approximate DBH)

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Sapling / Small Tree
Very Large / Mature Tree
DBH Conversions for 25 cm

Common DBH Examples

About DBH (Diameter at Breast Height)

What is DBH?

DBH (Diameter at Breast Height) is the standard method for measuring the size of a standing tree. It refers to the tree stem diameter measured outside the bark at a standardized height from the ground.

  • In most countries, breast height is defined as 1.3 meters (approx. 4.27 feet) above ground level.
  • In the United States, breast height is 4.5 feet (approx. 1.37 meters) above ground level.

This slight difference in standard height usually has a minor impact on the diameter measurement for most trees, but it's a good detail to be aware of in precise international comparisons.

Importance in Forestry
  • Tree Size & Growth: DBH is a primary indicator of a tree's size, age (in conjunction with other data), and growth rate over time.
  • Timber Volume Estimation: It's a critical input for calculating the merchantable timber volume of a tree and a stand.
  • Stand Structure & Density: Along with tree counts, DBH helps describe the structure (e.g., distribution of tree sizes) and density of a forest stand.
  • Forest Inventory & Monitoring: Repeated DBH measurements are essential for monitoring forest health, growth, and changes over time.
  • Ecological Studies: Used in biomass estimation, carbon sequestration calculations, and understanding forest dynamics.
Measurement Tools

DBH is typically measured using specialized tools:

  • Diameter Tape (D-tape): A flexible tape calibrated to directly read diameter when wrapped around the tree's circumference ($\text{Diameter} = \text{Circumference} / \pi$).
  • Calipers: Two-armed devices that measure the diameter directly across the stem.

On sloping ground, DBH is usually measured from the uphill side of the tree.