Drought Induced Tree Mortality SOE 306 Drought Induced Tree Mortality 1 Introduction 2 Temperature sensitivity 3 Global climate signal 4 Physiological mechanism introduction 5 Mechanistic investigation 6 Point of no return 2002 during drought Photo CD Allen in Breshears et al 2009 Frontiers in Ecol Env 2004 after drought Photo CD Allen in Breshears et al 2009 Frontiers in Ecol Env Tree die off can affect large areas Legend Forest Woodland Williams et al 2010 PNAS Tree die off can affect large areas Forest mortality 1997 2008 affected 11 of forest and woodland Legend Forest Woodland Die off Williams et al 2010 PNAS 2011 2013 2015 2012 2014 Pinus edulis Tree die off can affect large areas Meddens et al 2012 Ecol Appl Tree die off can affect large areas Huang et al 2019 New Phytologist Tree die off can affect large areas with big consequences British Columbia 2002 2008 420 Tg CO2 0 42 GT Stinson et al 2011 Huang et al 2019 New Phytologist Tree die off C consequences Berner et al 2017 Env Res Letters Tree die off a global phenomenon Hartmann et al 2018 New Phytologist updated from the UN Intergovernmental Panel on Climate Change IPCC AR5 Report 2014 Tree die off around the world New Mexico to Namibia California France Brazil Arizona Australia Oklahoma Tree die off in Washington Acres with Tree Mortality From Bark Beetles Shady Pass Chelan County WA Washington State DNR Forest Health and Resiliency Division 2017 and 2018 Reports How do we add these events to GC projections Adapted from Jentsch et al 2007 Front Ecol Env Empirical vs Process based Prediction Adams et al 2013 Drought Induced Tree Mortality 1 Introduction 2 Temperature sensitivity 3 Global climate signal 4 Physiological mechanism introduction 5 Mechanistic investigation 6 Point of no return Biosphere 2 Glasshouse Experiment Ambient Temp 4 3 C Watered No Water Adams et al 2009 PNAS Biosphere 2 Glasshouse Experiment 4 3 C 28 faster death Adams et al 2009 PNAS Implications for die off frequency Calculated a regional record of drought frequency Pi on pine Climate station 4 climate stations Drought months 50 of mean precipitation Shaw et al 2005 J of Forestry Implications for die off frequency Adams et al 2009 PNAS Implications for die off frequency 2002 Drought Adams et al 2009 PNAS Implications for die off frequency Adams et al 2009 PNAS 2002 Drought 4 3 C 28 Implications for die off frequency Adams et al 2009 PNAS 2002 Drought 4 3 C 28 Implications for die off frequency Adams et al 2009 PNAS 2002 Drought 4 3 C 28 Implications for die off frequency 4 3 C 28 5x 2002 2002 Drought 4 3 C 28 Adams et al 2009 PNAS Seedling Growth Chamber Experiment Adams et al 2017 Seedling Growth Chamber Experiment Adams et al 2017 Seedling Growth Chamber Experiment Adams et al 2017 Seedling Growth Chamber Experiment Linear T sensitivity non linear drought distribution non linear die off increase Adams et al 2017 Non linear drought frequency a common feature of climate Pullman WA 1895 2018 Non linear drought frequency a common feature of climate Seattle WA 1895 2023 Non linear drought frequency a common feature of climate Rochester NY 1926 2018 Summary Hotter droughts kill trees faster Frequency distribution of drought duration is non linear Future die off will respond progressively to temperature increase Drought Induced Tree Mortality 1 Introduction 2 Temperature sensitivity 3 Global climate signal 4 Physiological mechanism introduction 5 Mechanistic investigation 6 Point of no return wmhammond whatkillstrees Dr William Bill Hammond Assistant Professor of Plant Ecophysiology Agronomy Department University of Florida Gainesville Global Empirical Prediction 1 303 plots at 675 sites Hammond et al 2022 Global Empirical Prediction 6 monthly Climate variables Maximum temperature Vapor Pressure Deficit Climatic Water Deficit Precipitation Soil Moisture Palmer Drought Severity Index Each in most extreme month Normalized to 1958 2019 mean Hammond et al 2022 Global Empirical Prediction Hammond et al 2022 Global Empirical Prediction 22 increase 140 increase Hammond et al 2022 Downscaled Empirical Prediction 2002 Hammond et al 2022 Downscaled Empirical Prediction 2002 C D Allen Hammond et al 2022 Downscaled Empirical Prediction 2004 C D Allen Hammond et al 2022 Downscaled Empirical Prediction 1 C D Allen 2012 Hammond et al 2022 Downscaled Empirical Prediction 1 3 Hammond et al 2022 Downscaled Empirical Prediction Hammond et al 2022 1 3 5 Drought Induced Tree Mortality 1 Introduction 2 Temperature sensitivity 3 Global climate signal 4 Physiological mechanism introduction 5 Mechanistic investigation 6 Point of no return Physiological mechanism McDowell et al 2008 New Phytologist Physiological mechanism Hydraulic Failure Leaves Roots McDowell et al 2008 New Phytologist Physiological mechanism Hydraulic Failure Leaves Roots McDowell et al 2008 New Phytologist Physiological mechanism Hydraulic Failure Leaves Roots McDowell et al 2008 New Phytologist Physiological mechanism Hydraulic Failure Leaves Low embolism Roots Pinus taeda Loblolly pine Physiological mechanism Hydraulic Failure Leaves Low embolism High Embolism Roots Pinus taeda Loblolly pine Physiological mechanism Carbon Starvation Photosynthesis Non structural Carbohydrates Respiration McDowell et al 2008 New Phytologist Physiological mechanism Carbon Starvation Photosynthesis Non structural Carbohydrates Respiration McDowell et al 2008 New Phytologist Physiological mechanism Carbon Starvation Photosynthesis Non structural Carbohydrates Respiration McDowell et al 2008 New Phytologist Physiological mechanism Depends on xylem Sala et al 2010 New Phytologist McDowell et al 2011 Physiological mechanism McDowell et al 2022 Drought Induced Tree Mortality 1 Introduction 2 Temperature sensitivity 3 Global climate signal 4 Physiological mechanism introduction 5 Mechanistic investigation 6 Point of no return Mechanism at Biosphere 2 Adams et al 2013 New Phytologist Mechanism at Biosphere 2 Adams et al 2013 New Phytologist Mechanism at Biosphere 2 Adams et al 2013 New Phytologist Global synthesis of tree mortality mechanism 19 studies 26 species Conifers angiosperms Various tree life stages Loss of Hydraulic Conductivity PLC NSC Adams et al 2017 Global mechanism synthesis PLC Adams et al 2017 Global mechanism synthesis NSC Biosphere 2 example At time of Death Adams et al 2017 Global mechanism synthesis NSC Biosphere 2 example Normalized NSC At time of Death Adams et al 2017 Global mechanism synthesis NSC Adams