Growing Degrees Days of Development in Living Beings - Introduction of the Term

In 1730, French researcher René A. F. de Réaumur introduced the notion of Growing Degree Days (GDD), also known as heat units. Since then, GDDs have been used as a tool to prevent the growth stages of various biological entities, both of plant and animal origin.

Source: Fraisse, J., John Bellow, and Charles Brown (2010). Degree days: Heating, cooling, and growing. University of Florida