Can oxygen isotopes in tree rings be used to detect stomatal responses to global change?

Stomatal conductance (gs) regulates CO2 and water fluxes of plants. Although experiments have shown that gs decreases with elevated CO2, it is unclear how gs is responding in-situ to long-term exposures to rising CO2 and a changing climate. Tree ring isotope analysis provides a unique method to assess tree ecophysiological responses to long-term exposures to slowly changing environmental conditions. In particular, it has been suggested that changes in gs can potentially be inferred from tree ring stable oxygen isotope ratios (δ18Otrc). Several studies have indeed used δ18Otrc trends to conclude that gs has not significantly changed from pre-industrial values. However, it remains unclear whether δ18Otrc is sufficiently sensitive to detect the magnitude of change in gs expected due to CO2 increases and climatic changes. We deposit here the climate data and R scripts that we use to evaluate the sensitivity of δ18Otrc trends to CO2 and climate-in..., , # Can oxygen isotopes in tree rings be used to detect stomatal responses to global change?

Dataset DOI: [10.5061/dryad.905qftv01](https://doi.org/10.5061/dryad.905qftv01)

## Description of the data and file structure

R scripts and climate data used for modelling simulations and creating figures.

### Files and variables

#### File: SI.6_histogram.R

**Description:** R script for histogram (Fig. SI.6) which compares model-predicted 50-year change in tree ring d18O to real 50-year changes in tree ring d18O from 172 chronologies in 3 published studies.

* create xlsx file for Treydte et al (2023) data- download at [https://doi.org/10.25921/rt6p-df91](https://doi.org/10.25921/rt6p-df91)
* create xlsx file for Mathias and Thomas (2021) data- download at [https://doi.org/10.6084/m9.figshare.13541927.v2](https://doi.org/10.6084/m9.figshare.13541927.v2) 

#### File: 21.10_script.R

**Description:** R script for all models and all other figures. 

#### File: data_30.5.25.xlsx

**Description:...,