Leaf to landscape responses of giant sequoia to hotter drought: An introduction and synthesis for the special section

摘要: Abstract Hotter droughts are becoming more common as climate change progresses, and they may already have caused instances of forest dieback on all forested continents. Learning from hotter droughts, including where the landscape forests or less vulnerable to these events, is critical help resource managers proactively prepare for future. As part our Leaf Landscape Project, we measured response giant sequoia, world’s largest tree species, extreme 2012–2016 drought in California. The project integrated leaf-level physiology measurements, crown-level foliage surveys, remotely sensed canopy water content (CWC) shed light mechanisms spatial patterns response. Here summarize initial findings, present a conceptual model response, discuss management implications; details presented other four articles special section Giant Sequoias Drought. sequoias exhibited both leaf- canopy-level responses that were effective protecting whole-tree hydraulic integrity vast majority individual sequoias. Very few died during compared mixed conifer species; however, magnitude sequoia varied across landscape. This variability was partially explained by local site characteristics, variables related balance. We found low CWC an indicator recent dieback, which occurs when stress levels high enough adjustments alone insufficient maintain integrity. be useful indicators reveal vulnerability future droughts. Future work will measure recovery strengthen ability interpret maps. Our ultimate goal produce maps target actions, such reducing stressors, increasing resistance through prescribed fire mechanical thinning, planting projected suitable habitat, occur outside current grove distributions. suggest compare different types assessments combine with sources information inform decisions.