The Earth’s forests play a major role in taking carbon out of the atmosphere, but better understanding of trees’ annual cycles is needed to build more accurate models of the process.  

A project headed by Christine L. Goodale, the Frank H.T. Rhodes Professor of Environmental Science in the College of Arts and Sciences (A&S), will contribute to understanding of the role the nitrogen cycle and its seasonal variations play in estimates of future carbon uptake by the biosphere. The project is supported by a $1 million grant from the Department of Energy (DOE), part of a $13 million DOE program for environmental systems science.

Peter Hess, professor of biological and environmental engineering in the College of Agriculture and Life Sciences, is a co-investigator, along with Peter Groffman, City University of New York, and Qing Zhu, Lawrence Berkeley National Lab.

Their three-year project, “Are Trees Dormant During the Dormant Season? Determining the Importance of Plant Nutrient Uptake in Changing Cold Seasons in Cold-Region Catchments,” aims to build on a pilot study at Cornell’s Uihlein Maple Forest led by doctoral student Stephanie Freund and supported by an award from Cornell Atkinson’s Sustainable Biodiversity Fund. That pilot study found surprising amounts of plant activity during the dormant season by six different tree species.

With the DOE grant, the team will conduct related new studies at the whole-ecosystem scale at two sites – in Hubbard Brook, New Hampshire, and in the Arnot Forest, near Ithaca – to gain a better understanding of the nitrogen cycle.

“This matters in the broader context of understanding the role that forests play in taking up carbon out of the atmosphere,” said Goodale, who is also the faculty director for student and postdoctoral programs at the Cornell Atkinson Center for Sustainability. “One of the main missions of this DOE program is to improve representation of ecosystem processes in Earth system models, which project future climate based on what we understand about the Earth system today.”

Earlier generations of models had a carbon cycle only, Goodale said. The latest generation includes the nitrogen cycle and its constraints on plant growth, but some of these models’ assumptions require further testing, especially for dormant-season processes.

The project was one of 17 funded by the DOE that aim to provide improved understanding and representation of ecosystems and watersheds in ways that advance the sophistication and capabilities of models ranging from individual environmental processes to Earth-scale systems. Projects were chosen by competitive peer review under the DOE Funding Opportunity Announcement, under the Environmental System Science Research Program, sponsored by the Office of Biological and Environmental Research (BER), within the DOE’s Office of Science.

“Coupling of observational and experimental data with environmental modeling has been a hallmark of Biological and Environmental Research (BER)-supported research,” said Todd Anderson, DOE acting associate director of science for BER in DOE’s Office of Science. “These awards will result in a better grasp of critical processes linking climate and environmental systems needed to improve our ability to predict future impacts.”

Kate Blackwood is a writer for the College of Arts and Sciences.