What is DBH (diameter at breast height)?
DBH (diameter at breast height) is the trunk diameter of a tree measured at 4.5 feet above ground level, the standard reference point used in municipal tree ordinances and arboricultural assessments.
DBH stands for diameter at breast height and refers to a tree's trunk width measured at exactly 4.5 feet above grade level. This standardized measurement point was established to give municipalities, arborists, and property owners a consistent way to classify and regulate trees across different sites.
In Westchester County, DBH appears in local tree ordinances to determine when permits are required for removal, pruning, or construction near trees. Many municipalities use DBH thresholds to trigger protections. For example, a town may require a permit to remove any tree over 8 inches DBH, while smaller trees fall outside regulation. Arborists include DBH measurements in inspection reports and health assessments because the measurement directly affects what work can be done and what notices or approvals are needed from your town.
When you receive an estimate from a tree service company, the DBH of the target tree will influence labor, equipment, and disposal costs. Larger DBH values indicate older, more established trees that typically require more complex removal or more extensive root systems. Understanding DBH helps you communicate clearly with contractors about which tree you're discussing and what your local codes require before work begins.