OK this is fun.
I am guessing that the new fence was put up by the neighbor and he cut the trees without permission, and you are wondering if it is worth your while to confront him? The others are right -- stumpage refers to timber value less the cost of logging and transport to a mill.
The trees were worth something as far as ornamental trees go, but part of the estimate of value is based on your proven awareness of and enjoyment of the trees, the overall value of landscaping on the property and property values in the neighborhood. Value would mostly be based on screening if you didn't really know what was there except for the mass of foliage. You can hire a consulting arborist and pay them to estimate the value, but the party that cut the trees without permission could still ignore you unless you file a civil suit. Given the value likely was not all that high, maybe ask the party to plant something fast growing and call it good. Why make enemies?
The pic of the crowns you circled actually looks like it depicts what was coming from the smaller stump (about 10 in. wide based on 5 1/2 in. wide fence boards), because the stump looked like a fusion of two stems and the trees look about the same size. The bigger stump (about 16 in.) could be the tree farther to the right in the picture of the crowns. First tree could have been a volunteer Bitter Cherry; other tree maybe a Norway or Bigleaf Maple. That's a Western Red Cedar in the background, so probably in the PNW. The bigger tree may have been a volunteer along the fence line as well. I am thinking they are fence line volunteers because people generally don't plant trees there; perhaps the property was subdivided?
To Whomever cut 'em: always know where you are -- sometimes clients lie or figure the neighbor doesn't care. I always tell a potential client to talk to their neighbor if I am to remove or prune a tree on a boundary.