"When drought and heat co-occurred, stomatal closure triggered a runaway feedback loop: Impaired water transport led to loss of cooling, causing breaching of critical thermal thresholds. These events coincided with failures of photosystem II and scorching in drought-vulnerable beech, linking drought-induced stomatal limitation directly to thermal injury. Our results reveal that oak and beech can acclimate to warming alone, but not to simultaneous heat and drought, which together drive a hydraulic–thermal cascade exceeding both safety margins. This interaction sets fundamental limits on the resilience of temperate forests to future hot droughts." Alyssa T. Kullberg et al. (2026). "Hydraulic stress limits thermal acclimation in trees under chronic drought" https://doi.org/10.1073/pnas.2531865123 #desertification #droughts #forests #Europe