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Education

• Postdoctoral research: University of Florida and University of Texas
• Ph.D., Ecology & Evolutionary Biology, Columbia University
• B.Sc., Environmental Chemistry, University of California San Diego

Research Interests

I am an ecologist studying how forest ecosystems function and how they are changing under global change, with a particular focus on the resilience of the land carbon sink. My work spans a wide range of spatial and temporal scales, from individual trees to global carbon and nitrogen cycling, and from instantaneous physiological responses to geologic time. Research in the lab currently focuses on three lines of investigation:

Ecology of nitrogen-fixing trees

Symbioses between nitrogen-fixing bacteria and certain tree species provide the largest inputs of new nitrogen into many ecosystems. Nitrogen-fixing trees are thus critical to relieving the nitrogen limitation that constrains ecosystem productivity, such as in the early stages of ecosystem development or in response to rising atmospheric carbon dioxide. Combining experiments (field, greenhouse, growth chamber), observations, and theory, we investigate the ecology of nitrogen-fixing trees, the mechanisms that determine rates of nitrogen fixation, and the effects of nitrogen fixation on ecosystems.

Effects of global change on forest dynamics

Understanding how and why forests are changing is central to predicting the future strength of the land carbon sink. Due to factors such as rising atmospheric carbon dioxide, climate change, regrowth from previous land use, fire, and pest and pathogen outbreaks, forests are undergoing significant compositional and demographic (growth, mortality, recruitment) changes. We make use of forest inventory plot measurements to quantify and understand these changes and their implications for the land carbon sink.

Earth system modeling of carbon and nitrogen cycling

Earth system models allow us to forecast the future climate and functioning of ecosystems under various emissions scenarios. We collaborate with several international modeling groups to run modeling experiments that isolate the contributions of specific processes. This work ranges from targeted improvements within individual models to coordinated multi-model frameworks, and draws on empirical findings from our ecophysiological research to update model assumptions and evaluate simulations against field data.