OOS 21
Frontiers In Modeling Drought- and Insect-Induced Tree Mortality With Climate Change

Wednesday, August 7, 2013: 1:30 PM-5:00 PM
101B, Minneapolis Convention Center
William Anderegg
James A. Powell and Melanie Zeppel
Melanie Zeppel
Forest ecosystems store nearly half of the carbon found in terrestrial ecosystems and account for more than 55% of annual net primary production. They currently provide a strong carbon sink for anthropogenic carbon emissions, taking up nearly a quarter of human emissions of carbon dioxide. Yet the sensitivity of forests to drought, temperature and infestation-induced dieback has become apparent in global patterns of widespread forest die-off and increased rates of tree mortality during anomalously hot and dry periods. Tree mortality can have manifold impacts on ecological communities, ecosystem function, ecosystem services, biodiversity, and carbon sequestration, turning some forests into carbon sources. Drought/heat and infestation stress on forests is expected to intensify in many regions with climate change. Climate change will likely increase the frequency and severity of droughts in many regions, and the direct effects of temperature can be harmful to tree physiology and survival of droughts. Furthermore, changes in precipitation and increases in temperature can influence insect and disease population dynamics in diverse and non-linear ways, leading to devastating outbreaks across large regions. Despite its importance in the global carbon cycle and in regional scale forest health, tree mortality is simplistically represented in today’s ecosystem and vegetation models. So, while mortality prediction is critically important for long-term carbon cycle behavior and ecological impacts of climate change, we are only just beginning to appreciate the nature of the challenges involved. For this session, we have invited speakers who will provide a set of talks designed to present the current state of knowledge in this field, and identify the next critical steps to take to address gaps in our knowledge.
1:30 PM
 Plant hydraulic controls over the susceptibility of trees to mortality following climate-enhanced disturbances
D. Scott Mackay, SUNY-Buffalo; Brent E. Ewers, University of Wyoming; Scott D. Peckham, University of Wyoming; Phillip R. Savoy, SUNY-Buffalo; David Reed, University of Wyoming; John M. Frank, Rocky Mountain Research Station, U.S. Forest Service; Nate G. McDowell, Los Alamos National Laboratory
2:10 PM
 Analysis of drought mortality with a coupled xylem and phloem transport and leaf gas exchange model
Teemu Holtta, University of Helsinki; Maurizio Mencuccini, ICREA - CREAF and University of Edinburgh; Jordi Martínez-Vilalta, CREAF / Autonomous University of Barcelona
2:50 PM
 Why can't process-based models kill trees when modelling drought-induced mortality? How can we fix that?
Jean-Christophe Domec, North Carolina State University / Bordeaux Sciences Agro; Amanda Schwantes, Duke University; Daniel M. Johnson, Duke University; Jennifer J. Swenson, Duke University; Nate McDowell, Los Alamos National Laboratory; Jérôme Ogée, INRA; H. Wayne Polley, USDA, Agricultural Research Service; Will Pockman, University of New Mexico; Robert B., Jackson, Duke University
3:10 PM
3:40 PM
 A characterization of water transport regulation in plants: implications for drought-induced mortality
Jordi Martínez-Vilalta, CREAF / Autonomous University of Barcelona; Rafael Poyatos, CREAF; David Aguadé, CREAF / Autonomous University of Barcelona; Javier Retana, CREAF / Autonomous University of Barcelona; Maurizio Mencuccini, ICREA - CREAF and University of Edinburgh (UK)
4:00 PM
 Linking definitions, mechanisms, and modeling of tree mortality: An example of modeling drought-induced aspen die-off in Colorado
William R. L. Anderegg, Stanford University; Leander Anderegg, University of Washington; Alan Flint, USGS California Water Science Center; Lorraine Flint, USGS California Water Science Center; Joe Berry, Stanford University; Christopher Field, Carnegie Institution for Science