Data and code for: Local factors, not macroclimate, drive tree carbon supply and allocation at a temperate range boundary

This dataset supports the manuscript "Local factors, not macroclimate, drive tree carbon supply and allocation at a temperate range boundary," examining performance of yellow birch (Betula alleghaniensis) across a latitudinal gradient at its northern range boundary in western Quebec, Canada. Gas-exchange measurements were collected using a LI-6800 portable photosynthesis system with the Rapid A-Ci Response (RACiR) technique, on excised branches from 150 trees (adults and saplings) across 15 plots. Raw curves were corrected against empty-chamber reference measurements and, for a subset of trees, cleaned of clearly erroneous points through an interactive process; the exact per-curve range and outlier decisions from this step were not logged. Corrected curves are provided as individual CSV files (data/GasExchange/), along with an R script (fit_photosynthesis_parameters.R) that performs the fully deterministic step of fitting each curve to extract Vc,max and Jmax using the photosynthesis R package. Tree-ring samples were collected via increment cores from 75 adult trees, crossdated, and measured for annual ring width. Ring-width series are provided in standard .rwl format (data/rwl/), one file per plot. Plot-level topographic, soil, and vegetation community data, and monthly gridded climate data (temperature, precipitation) for each plot, are provided as CSV files. scripts/analysis.R documents the full statistical pipeline from these processed data files through to the reported analyses.