The Vegetation Diversity and Structure Indicator (VEG) is an extensive inventory of vascular plants in the forests of the United States. The VEG indicator provides baseline data to assess trends in forest vascular plant species richness and composition, and the relative abundance and spatial distribution of those species, including invasive and introduced species. The VEG indicator is one of several sets of measures collected by the Forest Inventory and Analysis (FIA) Program of the USDA Forest Service to assess forest health. This document describes the sampling design, field data collection methods, primary output objectives, and estimation procedures for summarizing FIA VEG data.