This project is focused on climate change effects on northern forests. Many studies have evaluated the impacts of variation in climate on forests within a single season, but few have examined the impacts across seasons and how these impacts may interact. Seasonal impacts may differ, and they may interact in ways that are either antagonistic or synergistic. For example, soil warming in summer may increase root growth, but warming in winter may increase the frequency of freeze/thaw cycles and damage plant root systems. The goal of this project is to determine the interactive effects of winter and growing season climate change on nutrient and carbon uptake in northern hardwood forests. This will be accomplished by establishing an ecosystem warming experiment at Hubbard Brook Experimental Forest, NH, and a greenhouse experiment at the Arnold Arboretum in Boston, MA. Data generated from these experiments will be used to modify an existing ecosystem-scale model (PnET-BGC) to improve its ability to predict ecosystem nutrient retention and carbon storage. This combination of experimentation and modeling will improve our understanding of the interactive effects of increased soil temperatures in the growing season and more frequent freeze/thaw cycles in winter, and may transform our thinking of how climate change will affect northeastern forests and other temperate ecosystems. This CAREER project will integrate research, teaching, and outreach. In particular, twenty-five high school teachers will be trained in forest ecology through formal lectures and field exercises. Ten high school students, ten undergraduates, and two graduate students will perform the hands-on laboratory and field experiments. Up to 240 undergraduate students at Boston University will participate in weekend field trips to learn about forest ecology and gain field research experience. Together, these activities will enhance scientific literacy and foster an understanding of the relationship between variation in climate and ecological processes for both students and high school teachers. Additionally, a new 'Sap-Net' network of maple syrup producers will be established to gain a better understanding of how variation in climate influences maple syrup production and quality.
