Our research investigates feedbacks between climate and terrestrial ecosystems of the Arctic and Boreal. We use both observational and experimental approaches to answer questions covering a range of spatial scales from individual leaves and fine roots to the landscape. Our recent projects have examined biogeochemical processes during winter, consequences of plant-herbivore interactions for ecosystem carbon cycling, implications of drying and vegetation succession for biogeochemical cycling in boreal wetlands and the causes and feedback consequences of changes in treeline.