This shapefile represents The Nature Conservancy’s (TNC) “essential forests” and “key connectors” in the Central Appalachians Whole System. Essential Forests are built around groups of large forest patches, ecoregional portfolio roll-up sites, and areas with high local integrity and high flow density (from M. Anderson’s resiliency analysis). Key Connectors provide physical linkages among essential forests, have high flow density, and may also include large forest patches and matrix blocks. The polygons were originally delineated by TNC staff at a workshop near Petersburg, West Virginia, on March 9 and 10, 2011. The boundaries were hand-drawn on paper maps and then hand-digitized by A. Watland (TNC-VA) and T. Gagnolet (TNC-PA). Boundaries and designations were then edited by J. Dunscomb (TNC-VA), A. Watland (TNC-VA), and T. Gagnolet (TNC-PA) based on group feedback over the course of several months in 2011. In the spring of 2012, TNC-PA staff added essential forests and key connectors in the High Allegheny Plateau ecoregion to complete the set for Pennsylvania. This version is current as of July 2012. See separate notes for detailed information on boundary edits.