CAREER: Understanding the production of maple syrup and carbon cycling within trees

This project improves understanding of how trees store, move, and use carbon by focusing on sugar maple (Acer saccharum). Sugar maple is an important tree species in northeastern North America and it is the foundation of the region’s rapidly growing maple syrup industry. Trees play a vital role in Earth system function by storing carbon, yet key aspects of how carbon is allocated within living trees—especially during periods without leaves—remain poorly understood. Sugar maple offers a unique natural system to address these knowledge gaps because sap extraction removes stored carbon during late winter. This creates an opportunity to directly observe how trees react to removal of some internal carbon reserves. This research advances fundamental knowledge about a longstanding question in plant physiology while supporting sustainable land management, rural economies, and STEM education. The project integrates research with education and public engagement focusing on sugar maple trees in a region with significant maple syrup production. Educational activities engage audiences ranging from K–12 students to professional maple producers through hands-on field experiences, a mobile sugarhouse, a new university course, undergraduate research opportunities, and continuing education programs. The project actively supports workforce development for a growing, forest-based industry. This project advances NSF’s priorities in Biotechnology. The goal of this project is to develop a detailed understanding of within-tree carbon cycling in sugar maple across seasonal and interannual timescales. The research pursues three integrated objectives: (1) quantifying seasonal patterns of carbon pools and fluxes using physiological measurements of processes, such as of growth and the evolution of sap composition and nonstructural carbon reserves; (2) experimentally testing controls on carbon allocation through field manipulations that alter carbon sources and sinks, including controlled sap extraction; and (3) developing a predictive simulation model of carbon transport and allocation within trees based on a transport-resistance framework. The project combines existing long-term datasets and novel observations with field experiments, enabling rare insight into carbon cycling of mature trees. Results are highly relevant to the maple sugaring industry. Together, these efforts will advance ecophysiological theory on carbon allocation in perennial plants, provide a template for studying other temperate tree species, and strengthen links between basic tree physiology, forest management, and the sustainability of the maple sugaring industry. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria. NSF Award ID: 2543476 | Program: 01003031DB NSF RESEARCH & RELATED ACTIVIT,01002627DB NSF RESEARCH & RELATED ACTIVIT | Principal Investigator: Tim Rademacher | Institution: University of Vermont & State Agricultural College, BURLINGTON, VT | Award Amount: $719,114 View on NSF Award Search: https://www.nsf.gov/awardsearch/show-award/?AWD_ID=2543476 View on Research.gov: https://www.research.gov/awardapi-service/v1/awards/2543476.html