How to explain the small undulating relief in this picture?

MAny explnations possible, but thy all need to be looked at in the field.
Ill pose one with the idea that I could be all qet.
The area appears to have been deforested aat some tim in the past for ag development. Ag soils often migrate into these types of undulating surfaces . They can be actually measured by looking at the thicknesses of the "plow layer" or a "residuum layer" where frost heave, water erosion, and farming practice can act hnd in hnd to develop small scale topographic features. Arcaeologists are learning to use these soil tools to locate past riverine or stream features or even pathways that were used by ancient humans.

First Id have really good soil scientist do cores in there to assess the physical properties down to the C layer .