This data set contains five data files, in comma-separated format (.csv), derived from the Walker Branch Watershed (WBW) vegetation inventory in eastern Tennessee. Field studies of permanent vegetation plots were conducted using one sampling design over a 40-year period (1967 to 2006). The data set contains long-term measurements of diameter at breast height (DBH) determined on stratified randomly-located inventory plots within the 4 different vegetation types (oak-hickory, pine-oak-hickory, pine, and mesophytic hardwoods) located in the WBW in 1967. The WBW plot-level vegetation DBH data are provided in four files. One file contains the complete set of inventory records (139,806 observations). To accommodate spreadsheet use, the complete inventory is split into three files, one containing 52,110 observations and the other two containing 48,231 and 39,465 observations, respectively. The fifth file contains the WBW vegetation species inventory with species names, the numeric species code for each species, a species group designation, the scientific name for each species, and the literature-derived ratio of g lignin/g N for leaves of each species. NPP values have been reported for various forest stands at different locations within the WBW by Olson et al. (2012a, b; DeAngelis et al. (1997); and Esser (1998). Total NPP values range from 380 gC/m2/yr for forest stands dominated by yellow poplar to 790 gC/m2/yr for forest stands dominated by oaks. Revision Notes: This updated vegetation inventory data set includes results of the 2006 survey and updates to previous results based on the latest survey. The 1967-2006 data set completely supersedes the 1967-1997 data set. If you downloaded the 1967-1997 data set before September 3, 2013, you should download the 1967-2006 version at your earliest convenience.