the ratio of an upper-stem diameter on a tree to DBH —note 1. form quotient is used as an independent variable with DBH and height to predict the volume of a tree stem —note 2. normal form quotient is the ratio of diameter at half tree height over DBH, and absolute form quotient (used for short trees) is the ratio of diameter at half tree height above breast height over DBH This definition last updated 10/24/2008