The database represents delineations of aspen stands associated with stand assessment data (SIERRA_SP_PTS) collected in aspen stands on lands administered by the Sierra District, California Department of Parks and Recreation, Placer, Eldorado, Sierra and Inyo Counties, California. This data was gathered during the summer of 2005. The stands were evaluated according to their priority with regard to stand loss. The dataset has 15 aspen stands, of which six have been assessed. Field surveys were conducted by trained USFS field staff. Surveys were not complete for the watersheds, and so this is not considered a comprehensive database of aspen in the region. Aspen stands were assessed and delineated using a protocol developed by the lead investigators. Associated with this polygon layer is a point layer (SIERRA_SP_PTS) containing aspen stand assessments conducted in conjunction with the aspen stand delineations. Data Compilation: The Aspen Delineation Project (ADP) is a collaborative effort of the U.S. Forest Services Pacific Southwest Region, the California Department of Fish and Games Resource Assessment Program, and the California Office of Bureau of Land Management. Principal Investigator for ADP is David Burton; visit: www.aspensite.org for more information regarding the ADP. The Department of Fish and Games, Resource Assessment Program compiled this information from the collaborating agencies and other researchers, and formatted the data into a common database for the purpose of facilitating access to data related to the conservation of Quaking Aspen in California. This information portal falls within the ADP goals to help agencies and land managers identify, map, treat, and monitor aspen habitats. This dataset is a portion of a master database compiled during a year long effort in 2005 to pull together current GIS layers and maps depicting Aspen communities in California.