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 45 tree species across 33 ecoregion sections (212 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 from 800-m PRISM LT data and drought frequency based on the 12-month SPEI in July (4-km). This project analyzes regional patterns of elevational redistribution and evaluates how climate change and disturbance regimes contribute to these shifts.