This shift in species composition in mixed-oak forests is often undesirable to natural resource professionals and society as a whole because oaks have both ecological and economic value (Smith 2006). Throughout the mid- Atlantic region, oaks grow on a variety of sites: from chestnut oak on xeric ridges to northern red oak on mesic lower slopes (Fig. 1.3). Oaks are long lived, quite resistant to rot, and grow to large sizes. These characteristics indicate that, once established, oak forests are relatively stable plant communities (Smith 2006). Once they achieve canopy dominance, oaks likely will persist for decades to centuries as they readily withstand insect outbreaks, lightning strikes, wind events, and ice storms. When damage does occur, the ability to compartmentalize rot helps ensure their continued survival (Shigo 1984). Injury sites may become cavities which, in turn, become dens for wildlife.