I have basic understanding of archeology and am willing to learn more how to detect landmarks more accurately. Finding big dips in the soil is easy, but how to know for sure it was a real mortarpit without digging? What to look for when searching for mortar pits?

I took this picture of a big dip within a few feet away from a large bunker. It could be a crash site, but could also be a mortarpit, or simply something else entirely different. Are there any specifics to determine it is a real mortarpit, like it’s location, position and indication of dense/less dense forests and shrubs? and would it survive all these years?

Note: The big dip was larger and deeper than it appears on the photograph.