This repository contains all observational data sets used for the paper: Sophia Etzold, Arun K. Bose, Arthur Gessler, Frank Krumm, Katrin Meusburger, Marcus Schaub, Anne Thimonier, Peter Waldner, Roman Zweifel (2026): Decreasing water availability reduces productivity in Swiss forests along an altitudinal gradient, Functional Ecology, https://doi.org/xxxxx.

Dataset 1: This dataset contains inventory measurements of individual trees, i.e. species, tree status, DBH (diameter at breast height), height, and BAI (Basal area increment).

Dataset 2: This dataset contains plotwise aggregated BAI and NPP data per inventory period, as well as stand and soil properties of the site (N trees, QMD, SDI, meanDBH, foliar N and foliar P, N deposition, LAI, main species) and meteorological parameters (deviation of T, Psum and SWP during vegetation period).

Dataset 3: This dataset contains site-specific properties (altitude, age in 2000, main species, Tmean long-term, Psum long-term, soil pH, soil C/N).

Dataset 4: This dataset contains annually resolved relative NPP data, based on inventory data (Dataset 2) and annual circumference measurements of individual trees, as well as relative annual Tmax and SWP.