hall's research interests are in the field of systems ecology with strong interests in biophysical economics, and the relation of energy to society. his work has involved streams, estuaries and tropical forests but focused increasingly on human-dominated ecosystems in the us and latin america. his research reflects his interest in understanding and developing analyses and computer simulation models of the complex systems of nature and humans and their interactions. halls focus has been on energy as it relates to economics and environment. his focus is studying material and energy flows referred to as industrial ecology, and applying this perspective, to attempting to understand human economies from a biophysical rather than just social perspective.