The coordination of dehydration tolerance and avoidance in oaks is mediated by leaf habit across a precipitation gradient

Abstract Forests worldwide are increasingly impacted by drought due to climate change, prompting plants to adapt through dehydration tolerance (DT) and avoidance (DA), two distinct physiological strategies. However, how these strategies are coordinated in response to varying precipitation remains unclear. To address this gap, we investigated key hydraulic traits associated with DT and DA in 11 oaks ( Quercus spp.) across a broad precipitation gradient (498–1793 mm year −1 ) in China. Specifically, we measured three DT traits: water potential at 50% loss of hydraulic conductivity ( Ψ P50 ), leaf turgor loss point water potential ( Ψ TLP ) and wood density (WD), as well as four DA traits: water potential at stomatal closure ( Ψ close ), minimum leaf conductance, branch capacitance and leaf‐to‐sapwood area ratio ( A L : A S ). When analysed collectively, most traits showed no significant relationship with precipitation or aridity. However, distinct patterns emerged when data were analysed by leaf habit. In evergreens, trait variation was largely and independently explained by mean annual precipitation (MAP), with stronger DT (lower Ψ P50 and Ψ TLP , higher WD) and enhanced DA (smaller A L : A S ) under drier conditions. In contrast, deciduous species showed weaker DT (higher Ψ P50 ) but stronger DA (higher Ψ close and lower A L : A S ) as precipitation decreased, with much variance driven by interactions between MAP and mean annual temperature (MAT). Notably, DT and DA traits were strongly correlated in evergreens but weakly associated in deciduous species. Our results show that evergreen oaks rely on both DT and DA strategies for drought adaptation, whereas deciduous species primarily depend on DA mechanisms. Considering DT alone is insufficient, and incorporating multiple DA strategies is essential for a mechanistic framework to understand forest responses. We highlight the need to integrate leaf habit and complementary drought strategies into predictive models and climate‐resilient forest management practices. Read the free Plain Language Summary for this article on the Journal blog.