Code for: Tree regeneration trends in forests of the northeastern USA and their implications for resilience and restoration

This R code assesses trends in abundance of trees, saplings and sapling recruits for common tree species from 2003 to 2023 across forests of the northeastern USA, based on Forest Inventory and Analysis (FIA) data.R scripts as are follows:"Subplot all FIA processing" and "Subplot RI processing" perform initial filtering, subsetting and joining from the entire FIA SQLite database file (downloaded June 3 2025)."Add ancillary data all FIA" and "Add ancillary data" add ancillary geospatial data based on public FIA plot coordinates."All FIA trends" examines species-level temporal trends."RI trends" examines small-sized seedling abundance from the Regeneration Indicator (RI) dataset."Sapling recruitment models" generates statistical models to predict likelihood of sapling recruitment from seedling abundance and other covariates, and "Recruitment predictions" generates predicted abundance of sapling recruits from these models."CCTA processing" analyzes future climate suitability through comparison with projected future change in species-level climate suitability from the Climate Change Tree Atlas."Trait scores processing" calculates weighted biological and disturbance scores."Witness tree comparison" compares modern tree, sapling and seedling composition with tree composition from early colonial land surveys."Recruitment maps" generates interpolated maps showing abundance at the start and end years of the analysis."Summary figure" generates a synthesis figure of results at the species level.<br>