This forest type is often found in areas that have a high degree of past or current human disturbance, and fragmentation, invasive species, or other threats that can reduce the adaptive capacity of particular locations. Many forests are located in fragmented landscapes. A history of fire suppression and reduced light reaching the forest floor has facilitated a shift to more mesic conditions and associated hardwood species (e.g., red and sugar maple, American beech, tuliptree). In many forests, regeneration of drought-tolerant oak and hickory trees is currently reduced due to fire suppression and competition from more shade-tolerant mesic species.