Southeastern mixed forests grow in below the pines. Sugar maple ("Acer saccharum"), a shade tolerant tree, grows amid the oaks and hickories in the northern part of this ecoregion. Mesic forests occur in fertile, mesic, low-elevation habitats such as deep ravines and sheltered north- or east-facing slopes. Dominant trees include American beech ("Fagus grandifolia"), tulip tree ("Liriodendron tulipifera"), northern red oak, white ash ("Fraxinus americana"), black maple ("Acer nigrum"), sugar maple ("Acer saccharum"), basswood ("Tilia americana"), and bitternut hickory ("Carya cordiformis"). Understory trees include pawpaw ("Asimina triloba") and painted buckeye ("Aesculus sylvatica"). Mesic mixed hardwood forests grow on mesic uplands, ravines, lower slopes,
Fagus sylvatica in the buds. In autumn, the tree builds the reserves that will sustain it into spring. Given good conditions, a bud can produce a shoot with up to ten or more leaves. The terminal bud emits a hormonal substance in the spring that halts the development of additional buds. This tendency, though very strong at the beginning of their existence, becomes weaker in older trees. It is only after the budding that root growth of the year begins. The first roots to appear are very thin (with a diameter of less than 0.5 mm). Later, after a wave of above