Too many deer?

I read in a book about the rewilding of Britain called Feral, by George Monbiot that the hills of Scotland were more forested until they were cleared... by and for sheep.

Then of course owners of great estates banned hunting on their land by local people, and wiped out the wolves so that their sport wouldn't be interfered with...

"William the Conqueror subsequently decreed that it (hanging) should be replaced by castration and blinding for all but the crime of poaching royal deer..."  (from The History of Hanging by Charles Duff.

This is an environmental man-made crisis, but it will be the deer that pay for it, of course.