This exploratory project examines how drought affects tree death across the continental United States. Research on drought and tree mortality is typically carried out at particular locations and on few species, in part because major droughts at the regional scale are relatively rare, hard to anticipate and hard to study. In contrast, this project uses a uniquely collaborative approach, referred to as open-source ecology, in order to develop a broader perspective of tree vulnerability to water stress based on the on-going major western regional drought of 2012. The project will document the physiological status, growth and annual mortality of trees across a number of different locations and species, leveraging data from national monitoring programs, such as the Forest Inventory and Analysis and NEON, and involving many institutions, investigators and students, to demonstrate how a coordinated continental measurement program could be fully implemented in the future.
Drought-induced tree mortality is an important but poorly understood process that leads to major uncertainties regarding the impacts of climate change on biodiversity, ecological communities, and the terrestrial carbon cycle. For example, current models of the carbon cycle either assume long-term background rates of mortality, or that mortality can be modeled in response to disturbances like fire, not in response to particular stressors that are well known to be important. In fact, no predictive model of drought-driven tree death across species or ecosystems currently exists. To carry out this pilot, more than 45 scientists have committed to work with many undergraduate and graduate students on field and lab measurements. A kick-off meeting at the 2012 Ecological Society of America Meeting will galvanize these commitments and enable recruitment of a more diverse national student group through the ESA program, Strategies for Ecology Education, Diversity and Sustainability. The project will also lay the foundation for national and potentially international coordination across disciplines beyond ecology, including atmospheric modeling, physiology, hydrology, remote sensing, and biogeochemistry. Finally, broad support from multiple communities assembled by the project creates a unique intellectual forum for a shared, collaborative, and open approach to developing the understanding and tools necessary to predict and manage drought impacts on forest ecosystems.
