Hackberry

Celtis occidentalis
This native Ohio tree is a tough survivor and can live up to 150-200 years. It can grow in soils that are moist, dry, rocky or clay and is pollution resistant.  However, it does prefer moist well-drained soil and full sun to maximally attain heights of 60-80 ft. and its spreading canopy of 40-60 ft.  This tree can be easily identified by its distinctive bark which is light gray, warty, with narrow cork-likeridges . The leaves are serrated with a pointy tip and turn light yellow in autumn. The leaves also can develop small nipple-like galls or protuberances. They are caused by insects that don't damage the tree. The tree gets its name from the Scottish word "hagberry" which is a common bird cherry.  Indeed , the mature pea-sized purple fruit is high in calories and nutrients. They are a good source of food throughout the winter for the birds. There are some very good specimens of this tree in Washington Park.
Arbor Day Foundation, ODNR, Wikipedia, Iowa State University