“Roughly Speaking”: Why Do U.S. Foresters Measure DBH at 4.5 Feet?

Abstract

This paper traces the history of diameter at breast height (DBH) tree measurements in the United States and suggests that DBH is a socially constructed scientific standard. In 1899, Gifford Pinchot—arguably the most important forester in U.S. history—claimed that 4.5 feet (ft) (137 cm) was the customary height for measuring the diameter of a tree’s trunk, which then became the default height in the United States. However, based on my review of archival forestry texts, there was wide variation in the heights used to measure trees pre-1900. Furthermore, my analysis of male anthropometric datasets contradicts assertions that 4.5 ft is a comfortable measurement height for men. Rather, 4.5 ft was likely Pinchot’s own BH. The selection of 4.5 ft might have also resulted from a mis-conversion of Bavarian forestry data. I discuss the social context in which the 4.5 ft standard emerged.