My interests lie in studying past environments using proxy records from tree-rings, most recently from the Asian tropics, but also in the Arctic and temperate forests of the world.  The tropics, however, offer unique challenges to dendrochronology and my work has taken me to areas from the logged teak forests of Thailand to the remote forests of Vietnam and Laos, where I am now developing records of past hydrologic changes going back more than 700 years.  This research has given me the ability to define periods of past persistent drought that sheds light on societal changes in response to monsoon climate dynamics.