Climate extremes are reshaping forest disturbance regimes worldwide. Hotter droughts, heatwaves and compound events are increasingly associated with growth decline, canopy dieback and pulses of tree mortality, reducing the carbon sink potential of forests, threatening biodiversity and impairing ecosystem services. Yet a central challenge remains unresolved: when does climate stress cross the threshold from reversible impairment to irreversible decline and death?
This session focuses on the early-warning signals, mechanisms and projections of tree mortality focusing on these irreversible shifts or transitions. We invite studies that connect hydraulic dysfunction, carbon and nutrient dynamics, wood formation, phenology and biotic stressors with growth, canopy condition and mortality data. We particularly welcome contributions that address:
• critical thresholds, drought legacies, compound extremes and early-warning signals preceding canopy dieback and tree death;
• hydraulic and carbon-related proxies and mechanisms of tree decline and mortality;
• resilience and recovery failure, including carryover effects or legacies across seasons and years;
• integration of tree rings, dendrometers, ecophysiological measurements, forest inventories, flux observations and remote sensing for monitoring forest health from trees to biomes;
• detection, mapping and forecasting of forest decline and mortality using Earth observation, machine learning, data-driven approaches and process-based models;
• vulnerability of large, old and senescent trees and old-growth forests, and the role of forest structure, composition and functional diversity in modulating climate risk;
• interactions among drought, heatwaves, fire, insects, pathogens and other natural or anthropogenic disturbances;
• harmonization of monitoring approaches and development of global datasets and networks for detecting changes in forest vitality and mortality;
• translation of vulnerability science into adaptive forest management, restoration strategies and decision-support tools.
By bringing together field ecologists, experimentalists, ecophysiologists, dendroecologists, forest and remote-sensing scientists, modelers and managers, the session will identify why some trees, stands and forests persist while others decline, which indicators provide robust and transferable warnings, and how those insights can support climate-resilient forest management.