To all,
While the farmlands in former West Germay, the Fulda area and Bavaria in general are not like the "endless" flat farmlands of Middle America, having been stationed there for five years I can safely say they are more open than you might expect.
First, the farm fields in that part of Germany are rarely, if ever, walled off or divided by hedgerows. The stock picture links presented earlier show the fields divided by farm roads, some even appear slightly raised but they also show that they provide long, open lines of site and fields of fire. It was not difficult to hover an AH-64 Apache just above a tree line or better yet, slide laterally out from behind a treeline, a few feet above the ground and have lines of sight/fields of fire that extended for a couple of kilometers. Yes, the ground does undulate and a good tanker can find sweet spots in the terrain that can provide low hull or hull down positions but by the same token, the opposite is also true where you could spot a tractor, a car, livestock, etc. sitting in the field from a long way off.
The main point is, while there is merit to the thought that obscuration impacts LOS and to Hit probability, let us not draw misconceptions about the topography in question.
I hope this helps.