An appreciation of apex-to-base variation in xylem traits will lead to more precise understanding of xylem phenotypic plasticity

Xylem air embolism is the primary cause of drought-related tree mortality. Phenotypic plasticity of xylem traits is key for species acclimation to environmental variability and evolution. It is widely believed that plants increase xylem embolism resistance in response to drought. However, I argue that this hypothesis, based on extensive literature, relies on sampling methods that overlook predictable anatomical patterns, potentially biasing our understanding of acclimation and adaptation strategies.