These fields seem to be (look like they are) slowly eroding away into barren wasteland. At 30,000 feet one can more easily see geographic transitions like this and it's one of the reasons I find flying so enjoyable.
Note: there was ice on the window and you can see it in the bottom of the image. Also, I bumped up the contrast some here to get it closer to the way it looked to my eye.
I posted a piece on my weblog about being "dugg" that some of you may find interesting to read if you're coming to this image late: I felt the digg effect.