Data and Code for: Tree rings Show Global CO2-driven Rise in Leaf Photosynthesis and Decrease in Stomatal Conductance Since 1901

This repository contains the data, analysis code, and documentation required to reproduce the results presented in the manuscript: Tree Rings Show Global CO₂-driven Rise in Leaf Photosynthesis and Decrease in Stomatal Conductance Since 1901 (Haagsma et al., Science Advances). The repository includes processed tree-ring isotope datasets, metadata, CLM5 comparison datasets, reconstructed historical estimates of leaf photosynthesis (Anet), stomatal conductance (gs), transpiration (T), intrinsic and apparent water-use efficiency (iWUE and aWUE), and the Python scripts used to generate all analyses and figures presented in the manuscript. The workflow is organized sequentially into scripts that (1) reconstruct original tree-ring δ¹³C observations from previously published databases, (2) reconstruct intercellular CO₂ concentration (ci), (3) estimate leaf-level gas exchange using a biochemical photosynthesis model under historical and alternative CO₂ acclimation scenarios, and (4) generate the figures included in the manuscript. Intermediate and final processed datasets required to reproduce the analyses are included. The repository is organized into two main directories: Code/ – Python scripts for data preparation, ci reconstruction, gas-exchange modeling, statistical analyses, and figure generation. Data/ – Input datasets, intermediate products, reconstructed outputs, metadata, and CLM5 comparison datasets. A detailed description of each file, software requirements, repository structure, and the complete processing workflow is provided in the accompanying README.