Celtis occidentalis, Sugarberry, Nettletree
This common hackberry tree grows in Hopkinsville, Kentucky, on the Catholic church property. Its bark is fairly smooth with occasional warty areas and raised creases.
All of the hackberry trees I've seen around here have bark similar to this. None of them have bark that would be described as ridged.
Thus, I was surprised to read this sentence about hackberries in The Trees of North America by Alan Mitchell: "In Central Park [New York City], the trees have smooth gray bark, but it is normally well covered in dark, abrupt, broken ridges 1 in. thick."
The Audubon field guide shows hackberry bark that is similar to that in the photo above, but Trees & Shrubs of Kentucky has a photo of a hackberry trunk with ridged bark. More research in other texts yields more conflicting descriptions of the bark's texture.
I did notice that the word "warty" appears in most of the descriptions. Even the ridges were described as warty.
Probably there are regional variations in the bark, but Carl Settergren and R.E. McDermott in Trees of Missouri suggest another explanation. "Bark: Grayish with warty projections, smoother on more vigorous trees."