My primary research interest is understanding what controls ecosystem metabolism-the exchange of carbon and water between forests and the atmosphere. I'm interested in understanding how changes in climate, land use, forest age, and disturbance will affect forest productivity and the role of forests in the global carbon cycle. Within this area, I've focused on understanding what controls changes in productivity and carbon cycling with stand development, the role of plant respiration in controlling productivity, ecosystem respiration, carbon and nitrogen interactions, and decomposition of soil carbon.