City Park is known for having one of the largest collections of mature live oaks in the world. The oldest is rumored to be up to 800 years old, although most sources claim the oak's age is closer to 500 years. Live Oaks are evergreen, but their leaves are sparse in the winter. These trees have a unique low-slung spread and form. Established trees commonly have lateral limbs that extend to the ground. Many mature trees have a branch spread that is double the height of the tree. Children are often seen climbing the limbs of trees adjacent to the playground.
The McDonogh, Dueling and Ansman Oaks are located amongst the remnants of a forest that began long before Iberville and Bienville first scouted the area. They declared this land for the establishment of the city and port that developed into New Orleans. City Park's eldest and largest live oaks can be found along the remnants of old Bayou Metairie, a vestige of an old distributary of the Mississippi River better known today as the City Park Lagoon.