My lab group studies evolution, ecology and historical biogeography of plants in temperate and tropical forests.  I am particularly interested in understanding the drivers of tree species richness. Our study sites are in Central America, Andean slopes and the Amazon basin. We also work in deciduous forests of eastern North America.

In my role as Director of the University of Michigan Herbarium and of the E.S. George Reserve, I am  involved in the stewardship of biological collections and coordination of ecological research in SE Michigan.