DOI: 10.5061/dryad.8cz8w9h3p
title: Data from:Quantitative wood anatomical characteristics, basal area increments (BAI) and tree-ring derived intrinsic water-use efficiency (iWUE) for three coniferous tree species in Central Spain

description: Increasing aridity is a major threat to forests worldwide. Understanding
 tree functional constraints under drought and their impacts on resilience
 and mortality among species is crucial to assess global change on forests.
 We analyzed the long-term drought and atmospheric CO₂ responses in three
 Mediterranean co-occurring species with differing drought tolerances
 (Pinus pinaster &lt; Pinus pinea &lt; Juniperus oxycedrus). In
 this mixed forest, P. pinaster exhibited widespread mortality and
 mistletoe infection, P. pinea showed scattered mortality, and J. oxycedrus
 showed no decline. Using tree-ring data (1978–2016), we compared intrinsic
 water-use efficiency (iWUE) and xylem hydraulic traits in healthy and
 non-healthy individuals of both pine species and healthy junipers. Healthy
 P. pinaster trees produced a more hydraulically efficient xylem, with
 wider lumen tracheids, than non-healthy trees, whereas P. pinea showed no
 anatomical differences between health status. Healthy P. pinaster
 displayed greater anatomical plasticity, adjusting hydraulic conductivity
 and cell-wall thickness to water availability. Despite small differences
 in average iWUE, the response of iWUE to rising CO2 and drought differed
 between species and health status. J. oxycedrus and P. pinea showed steady
 iWUE increases, but P. pinea experienced periods of stagnation following
 an extreme drought, later recovering regardless of health status. In
 contrast, iWUE in P. pinaster plateaued for over 20 years after a
 drought-inducing drought, particularly in non-healthy, mistletoe-infected
 trees. Differences in iWUE response to CO2 and anatomical plasticity to
 drought may explain the contrasting mortality patterns among these
 coniferous species. Our results suggest a long-term decline spiral in P.
 pinaster induced by low hydraulic efficiency in drought-induced defoliated
 trees and limited physiological response to rising CO₂ and drought.
 Increasing drought stress makes pine recovery increasingly unlikely.
description: **GENERAL INFORMATION** **1.   Title of Dataset**: Quantitative wood
 anatomical characteristics, basal area increments (BAI), and tree-ring
 derived intrinsic water-use efficiency (iWUE) for three coniferous tree
 species in Central Spain from Martin-Benito, D. et al (2025). Loss of
 stomatal regulation sensitivity to CO2 and reduced xylem hydraulic
 conductivity contribute to long-term tree decline and mortality. Global
 Change Biology DOI:10.1111/gcb.70221 **2. Author Information** **A.
 Principal Investigator** Name: Dario Martin-Benito **Contact Information**
 Institution: ICIFOR, INIA-CSIC Address: Ctra. La Coruña km 7.5  28040
 Madrid (Spain) Email: [dmartin@inia.csic.es](mailto:dmartin@inia.csic.es)
 **B. Co-investigator iformation:** Names: Macarena Férriz María Conde
 Georg von Arx Patrick Fonti José Miguel Olano Guillermo Gea-Izquierdo **3.
 Date of data collection:** During 2016 and 2017 **4. Geographic location
 of data collection:** Iberian Central Mountain Range (40.5º 182 N; 4.29º
 W) **5. Information about funding sources that supported the collection of
 the data:** Projects PID2019-110273RB-I00 and PID2022-142746NB-I00, 
 AGL2015-73190-JIN, RYC-2017-23389, AGL2014-61175-JIN, RyC-2014-15864 from
 MCIN/AEI, and TED2021-131947B-100 funded also by the EU
 NextGenerationEU/PRTR. Project CALEIDOSCOPE (212902) from the Swiss
 National Science Foundation. **DATA & FILE OVERVIEW** **File List**:
 1\. Data_BAI_conifers_Martin-Benito_GCB.csv 2\.
 Data_iWUE_conifers_Martin-Benito_GCB.csv 3\.
 Data_QWA_conifers_Martin-Benito_GCB.csv **METHODOLOGICAL INFORMATION** For
 a complete description of the methodologies used for data collection see
 Martin-Benito et al. (2025) Global Change Biology **DATA-SPECIFIC
 INFORMATION FOR:** 1\. Data_BAI_conifers_Martin-Benito_GCB.csv ·      
 Number of variables: 6 ·       Number of cases/rows: 4655 ·       Variable
 List: | **Variable** | **Description** | **Values** | | :------------ |
 :--------------------------------------------------- |
 :---------------------------------------- | | species | Tree species | *P.
 pinaster*, *P. pinea*, *J. oxycedrus* | | status | Health status |
 healthy, declining, dead | | tree | Tree code | Unique tree code | | year
 | Year of tree ring formation | From 1978 to 2016 | | ring\_section |
 Section of the tree ring where variable was measured | tree-ring (complete
 annual ring) | | BAI | Basal area increments (cm2 year-1) |   | 2\.
 Data_iWUE_DELTA13C_conifers_Martin-Benito_GCB.csv ·       Number of
 variables: 7 ·       Number of cases/rows: 1016 ·       Variable List: |
 **Variable** | **Description** | **Values** | | :------------ |
 :--------------------------------------------------- |
 :---------------------------------------- | | species | Tree species | *P.
 pinaster*, *P. pinea*, *J. oxycedrus* | | status | Health status |
 healthy, declining, dead | | tree | Tree code | Unique tree code | | year
 | Year of tree ring formation | From 1978 to 2016 | | ring\_section |
 Section of the tree ring where variable was measured | tree-ring (complete
 annual ring) | | DELTA13C | Carbon isotope discrimination (Δ13C) |   | |
 iWUE | Intrinsic water-use efficiency (μmol CO2 mol H2O-1) |   |
 3.Data_QWA_conifers_Martin-Benito_GCB.csv ·       Number of variables: 10
 ·       Number of cases/rows: 2250 ·       Variable List: | **Variable** |
 **Description** | **Values** | | :------------ |
 :-------------------------------------------------------------------------
 | :-------------------------------------------------------------- | |
 species | Tree species | *P. pinaster*, *P. pinea*, *J. oxycedrus* | |
 status | Health status | healthy, declining, dead | | tree | Tree code |
 Unique tree code | | year | Year of tree ring formation | From 1978 to
 2016 | | ring\_section | Section of the tree ring where variable was
 measured (EW, LW or tree-ring) | EW (earlywood), LW (latewood), tree-ring
 (complete annual ring) | | CWT | Cell-wall thickness (mm) |   | | LA |
 Lumen area (mm2) |   | | Kh | Theoretical xylem hydraulic conductivity
 (10-12, kg m-1 s-1 MPa-1) |   | | TB2 | Resistance to implosion factor |  
 | | Num\_cells | Number of tracheids per ring |   |