How do I ADD fieldstone to a map in the editor?

[Dim67]

Yes, I want MORE fieldstones. I am playing on Rehbach and the fields only have a few lines of stones in each field. So basically having fieldstones turned on is even more pointless. I want to be able to get a decent amount of stones from the field so I can use a Lime production mod.
I dont know how these lines were drawn in. Also, once I have that fixed in the editor, I need to transfer that info to my current save.