Large-scale phenological shifts, or timing of key life events, have been observed across many ecosystems and are consistent with changes expected with climate change. With annual temperature increases of roughly 0.2 degrees C, advancement in the timing of budburst and flowering have been widely observed. Earlier budburst and therefore longer growing seasons may have significant implications for carbon storage. Previous research has shown that increases of only one day in growing season have significantly increased forest net ecosystem productivity (NEP). However, the relationship between earlier budburst and NEP is not well established. Kellen’s research will examine the connection between phenological events at the species levels and phenological timing at the stand scale. In contrast with the more evident relationship among increased temperature, earlier onset of budburst, and increased NEP, the connections between phenology and local, boundary-layer meteorology are much less understood. Leaf-out has been correlated with a wide variety of meteorological components including temperature, vapor pressure, and relative humidity. Kellen’s research will use precise phenological and meteorological observations to develop climate-biosphere models and determine the effects of phenological shifts on the climate-biosphere linkage so these findings can be incorporated into climate models. Changes in timing of autumnal senescence have also been widely observed, although changes are more variable between ecosystems and more poorly understood than budburst events. Delayed leaf abscission may cause incomplete resorbtion of nutrients to storage organs as well as less N. 1. Have shifts in the timing of spring phenology occurred at Wauseon, OH in comparison to legacy data sets from the 1880's-1913? 2. How will shifts in both spring and autumn phenology impact carbon storage dynamics in northern forest ecosystems with the shift from aspen and birch dominated canopies to more heterogeneous oak and maple forests? 3. How will shifts in timing of leaf fall impact nutrient resorption dynamics? 4. What are key meteorological drivers of phenological events?