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

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 < Pinus pinea < 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 dis..., , **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: [[e-mail]](mailto:[e-mail])

**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 (...,