Elevational shifts in tree species in western US driven by climate and disturbance

This repository contains the data and R code used to quantify elevational shifts for 44 tree species across 31 ecoregion sections (184 species–section combinations) in the western United States and to assess the roles of climate and disturbance in these shifts. Elevational shifts and disturbance information were derived from USDA Forest Service Forest Inventory and Analysis (FIA) tree remeasurements. Climate variables including mean annual temperature and drought frequency based on the 12-month SPEI in July were obtained from 4-km PRISM data. This project analyzes regional patterns of elevational redistribution and evaluates how climate change and disturbance regimes contribute to these shifts.