We maintain long-term records of air temperature, precipitation, stream temperature, streamflow, snowpack, and lake ice cover and study how the forest ecosystem at Hubbard Brook is responding to a changing climate. We have one of the world’s most detailed records of tree phenology, including budbreak and leaf expansion in spring and color change and leaf drop in fall. We are using innovative acoustic monitoring techniques to track the arrival time of migratory birds, and our detailed population study of black-throated blue warblers looks for behavioral and demographic responses to climate change. We study how reduced snowpack and increased soil freezing during the winter and soil warming during the summer will impact forest productivity and soil processes across seasons. We measure how increasingly frequent and intense extreme weather events—particularly droughts and ice storms—alter forest ecosystem processes. These records show marked changes in climate, and in the variability of climate over the past 50 years. The ecosystem response to these changes has been neither simple nor linear, but arises from cumulative responses to climate dynamics operating at multiple time scales.
