Dear all,

The International Tree Mortality Network, an initiative of the IUFRO task force on monitoring trends and patterns in global tree mortality, continues the online seminar series join on June 22, 5 pm CEST, with:

Dr. Craig D. Allen

Title: The global emergence of hotter-drought drivers of forest disturbance tipping points

Abstract: Current research is presented on global-scale patterns and trends of forest responses to increasingly hotter droughts, particularly extensive tree mortality and forest die-offs involving a range of interactive disturbances (e.g., water stress, insect outbreaks, high-severity wildfire). Diverse cross-scale observations and empirical findings increasingly indicate that amelioration of hotter-drought stress via fertilization of photosynthesis from elevated atmospheric CO2 concentrations may soon be overwhelmed by heat and accelerated atmospheric drought. These findings highlight some current challenges in realistically projecting the future of global forest ecosystems (and their associated carbon pools and fluxes) with process-based Earth system models. In particular there is substantial evidence that forests dominated by larger, older trees may be disproportionately vulnerable to increased growth stress and mortality under hotter-drought conditions. The fates of these old trees in response to global change are of vital importance, given that they are essential as: a) disproportionately large carbon sinks; b) among the most biodiverse and rare terrestrial ecosystems; c) irreplaceable archives of environmental history; and d) venerated for many cultural reasons. Key scientific uncertainties that impede modeling progress are outlined, and examples of promising empirical modeling approaches are illustrated.

Bio: Craig D. Allen is an adjunct professor in the Department of Geography & Environmental Studies at the University of New Mexico. He recently retired as a research ecologist and founding leader of the New Mexico Landscapes Field Station for the U.S. Geological Survey, based at Bandelier National Monument in the Jemez Mountains of northern New Mexico, where he has conducted ecological research since 1981. Craig conducts place-based, long-term research on the ecology and environmental history of southwestern US landscapes, and the responses of western US mountain ecosystems and forests globally to climate change, with many international collaborations.  Since 1986 his office has been co-located with land managers at Bandelier National Monument where he continues to collaboratively volunteer, reflecting his commitment to provide scientific and technical support to diverse land management agencies, Native American tribes, and governmental and non-governmental organizations.  Craig received B.S. and M.S. degrees in Geography from the University of Wisconsin-Madison, and a Ph.D. in Wildland Resource Science (forest & landscape ecology, conservation biology) from the University of California-Berkeley.  He is an elected fellow of the Ecological Society of America (ESA) and the American Association for the Advancement of Science (AAAS).

Please register for the Zoom Webinar: