Northern Forest DroughtNet: A New Framework to Understand Impacts of Precipitation Change on the Northern Forest Ecosystem

Tuesday, 16 December 2014
Heidi Asbjornsen1, Lindsey Rustad2, Pamela H Templer3, Katie Jennings1, Richard Phillips4 and Melinda Smith5, (1)University of New Hampshire Main Campus, Durham, NH, United States, (2)USDA Forest Service, Northern Research Station, Durham, NH, United States, (3)Boston University, Boston, MA, United States, (4)Indiana University, Bloomington, IN, United States, (5)Colorado State University, Fort Collins, CO, United States
Recent trends and projections for future change for the U.S. northern forests suggest that the region’s climate is becoming warmer, wetter, and, ironically, drier, with more precipitation occurring as large events, separated by longer periods with no precipitation. However, to date, precipitation manipulation experiments conducted in forest ecosystems represent only ~5% of all such experiments worldwide, and our understanding of how the mesic-adapted northern forest will respond to greater frequency and intensity of drought in the future is especially poor. Several important challenges have hampered previous research efforts to conduct forest drought experiments and draw robust conclusions, including difficulties in reducing water uptake by deep and lateral tree roots, logistical and financial constraints to establishing and maintaining large-scale field experiments, and the lack of standardized approaches for determining the appropriate precipitation manipulation treatment (e.g., amount and timing of throughfall displacement), designing and constructing the throughfall displacement infrastructure, identifying key response variables, and collecting and analyzing the field data. The overarching goal of this project is to establish a regional research coordination network – Northern Forest DroughtNet – to investigate the impacts of changes in the amount and distribution of precipitation on the hydrology, biogeochemistry, and carbon (C) cycling dynamics of northern temperate forests. Specific objectives include the development of a standard prototype for conducting precipitation manipulation studies in forest ecosystems (in collaboration with the international DroughtNet-RCN) and the implementation of this prototype drought experiment at the Hubbard Brook Experimental Forest. Here, we present the advances made thus far towards achieving the objectives of Northern Forest DroughtNet, plans for future work, and an invitation to the larger scientific community interested in precipitation manipulation experiments in forest ecosystems to participate in the network.