DOI: 10.5061/dryad.gtht76j1s
title: Data from: The coordination of dehydration tolerance and avoidance in oaks is mediated by leaf habit across a precipitation gradient

description: 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 eleven oaks (Quercus spp.) across a broad
 precipitation gradient (498-1793 mm yr-1) in China. Specifically, we
 measured three DT traits: water potential at 50% loss of hydraulic
 conductivity (ΨP50), leaf turgor loss point water potential (ΨTLP), and
 wood density (WD), as well as four DA traits: water potential at stomatal
 closure (Ψclose), minimum leaf conductance, branch capacitance, and
 leaf-to-sapwood area ratio (AL:AS). When analyzed collectively, most
 traits showed no significant relationship with precipitation or aridity.
 However, distinct patterns emerged when data were analyzed by leaf habit.
 In evergreens, trait variation was largely and independently explained by
 mean annual precipitation (MAP), with stronger DT (lower ΨP50 and ΨTLP,
 higher WD) and enhanced DA (smaller AL:AS) under drier conditions. In
 contrast, deciduous species showed weaker DT (higher ΨP50) but stronger DA
 (higher Ψclose and lower AL:AS) 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.
description: # Data from: The coordination of dehydration tolerance and avoidance in
 oaks is mediated by leaf habit across a precipitation gradient Dataset
 DOI: [10.5061/dryad.gtht76j1s](https://doi.org/10.5061/dryad.gtht76j1s) ##
 Description of the data and file structure ### Files and variables ####
 File: Oak_DADT.csv **Description:** This is the hydraulic trait data
 derived from Liang et al. (2025, Functional Ecology). ##### Variables *
 Site: Study sites * Species: Tree species * Leaf habit: Leaf habit of tree
 species * Latitude: Latitude (°) * Longitude: Longitude (°) *
 DBH: Diameter at breast height (cm) * Height: Tree height (m) *
 Psi_P50: Water potential at 50% loss of xylem conductivity (MPa) *
 Psi_close: Water potential at stomatal closure  (MPa) * Psi_TLP: Water
 potential at leaf turgor loss point (MPa) * WD: Wood density (g cm^-3^) *
 Cbranch: Branch capacitance (RWC MPa^-1^) * gmin: Minimum leaf conductance
 (mmol m^-2^ s^-1^) * Al:As: Leaf-to-sapwood area ratio (m^2^ cm^-2^) *
 MAT: Mean annual temperature (°C) * MAP: Mean annual precipitation (mm) *
 AI: Aridity index (unitless) * PET: Potential evapotranspiration (mm) *
 VPD: Vapor pressure deficit (kPa)