Sometimes the grass cutters aren't great respecters of the naturalization areas. In the above picture they mowed a swath through the naturalization area, ignoring the "do not mow" sign.
And sometimes a minor obstruction diverts the path of the mowers and effectively expands the area left to the care of mother nature. This spring I placed a log (picture below) on the edge of the 2010 naturalization area to protect a spruce tree that had been damaged by the mowers. However, it seemed like every time I passed by, this log had moved a short distance away onto the short grass between the spruce tree and a crabapple tree. I would return it to the original spot only to find it had moved once again the next time I came by. Eventually I gave up and there it stayed, in the mower's path for the rest of the summer. That seemed to be enough of an excuse for the mowers, and they just gave up mowing the upper part of the berm. The grass grew unruly, the sumac encroached, and poplar suckers sprung up.
It was a bit of a mystery who kept on moving the log back until one day I happened upon a couple who were using the log as a private place to sit and be together.