Urban Crop Circles

I thought all of these pictures would be lined up neatly on the left side of the screen in the order that I downloaded them, but I guess not. Given that I am actually too lazy this morning to figure out if I could change this, you will just have to deal with it.

These pictures were taken near the Chicago River, just before it heads out into the lake. I was walking down there with my gf, her sister, and the two dogs when I saw this. This was the only set of trees that had these circles or rows around them. Since they are so neat and precise it's obvious that they were not created by accident. Also, in the troughs there were apples that had been cut in half. Very odd....

Who did this and why? Was there something special about these two trees (other similar trees and beds had not been disturbed)? The two ladies did not think too much about it, and neither of the dogs reacted (maybe aliens don't smell?). However, since I think it's much more fun to believe they are urban crop circles, I declare them urban crop circles!