A tough, fast-growing native red-group oak of the eastern and central United States, and one of the most widely planted street and lawn oaks for its quick establishment and clean pyramidal-when-young form. Mature trees reach 50-70 feet with a distinctive three-tier branch habit: ascending upper limbs, horizontal middle branches, and gracefully drooping lower limbs that sweep toward the ground. The honest catch is soil chemistry: pin oak is highly prone to iron chlorosis (interveinal yellowing of the leaves) on alkaline or high-pH ground, so it is the right tree only on acidic, moist, well-drained sites — on limestone or alkaline soils choose Shumard oak or swamp white oak instead. NC State Extension also flags it as poisonous: the acorns and foliage carry tannins that are toxic to horses and livestock in quantity. As an oak, though, it is a keystone wildlife tree — Quercus is the single most important larval host genus for native moths and butterflies in North America, and the acorns feed birds and mammals.