Michael G. Ryan, PhD.

Research Ecologist Emeritus

USDA Forest Service

Fields of Expertise

Ecosystem Dynamics

Areas of Interest

Causes of tree mortality, Changes in tree physiology and ecosystem processes with tree age, Disturbance effects on landscape carbon cycling


Michael Ryan is an emeritus research ecologist for the USDA Forest Service, Rocky Mountain Research Station. His research focuses on whole tree physiology; this includes the role of respiration in regulating productivity, tree carbon balance, mechanism of size-related productivity decline, mechanisms of drought tolerance and mortality, carbon allocation, the role of source vs. sink control of plant carbon balance, and other aspects of the forest carbon cycle. Ryan received his B.S. in biology from the University of Pittsburgh. He then studied forest science, earning his M.S. from Northern Arizona University and his Ph.D. from Oregon State University.