The U.S. Forest Service's Forest Inventory and Analysis (FIA) program collects sample plot data on all forest ownerships across the United States. Its primary objective is to determine the extent, condition, volume, growth, and depletion of timber on the Nation's forest land. The standard for distributing FIA data is the Forest Inventory and Analysis Database (FIADB). FIADB data for individual States can be downloaded from the FIA DataMart at http: //fi a.fs.fed.us/toolsdata/ default.asp as Microsoft Access databases which can be used to generate estimates of forest area, number of trees, volume, biomass, growth, removals, and mortality. The methodology used to estimate live-tree gross, net, and sound volume for the 24 states inventoried by the Northern Research Station's (NRS) FIA unit is documented. Sound volume is of particular interest because it is used in live-tree biomass and carbon estimates. The NRS currently uses four volume equations for each of four geographic regions