OOS 40-7
Climate change effects on hydrologic processes in northern forests
Across Northern Forests in the Central and Eastern US and Southeastern Canada, landscapes range from high elevation, mountainous systems in the East where streams are driven by mainly upland runoff, to relatively low-relief systems in the Midwest where streams are the result of both upland and wetland runoff. Across this gradient, climate change is expected to affect hydrologic processes differently and two sites span the geographic and geomorphic range of this region: Hubbard Brook Experimental Forest (HBEF) in New Hampshire, and the Marcell Experimental Forest (MEF) in Minnesota. Each site has hydrologic and meteorological records for the past 50 years.
Results/Conclusions
We compared and contrasted how climate change has affected changes in hydrologic processes such as precipitation, streamflow, evapotranspiration, soil moisture, snow melt timing, as well as the overall water budget at the HBEF and the MEF. Initial analyses on the HBEF show increases in precipitation, soil moisture, and streamflow, with unchanging or small decreases in evapotranspiration. At MEF there were no significant changes in long-term annual precipitation, streamflow has increased in spring but decreased in summer, and there are declining trends in soil moisture. Also, the date of snow melt is tending to be earlier over time. Metrics to assess changes in the variability in streamflow (i.e. extreme events) will also be presented. Based on our current projections and predictions of future climate, we speculate on the future hydrology of HBEF and MEF and the possible ramifications.