Those guys are speaking German which leads me to believe that those are centuries old trails in the Alps in the region between Austria and Italy.
I've ridden trails at Cle Elum and they are mini versions of what you see in this video.One mistake and you fall 30 ft into a rock gorge.It's o.k. on a very precise steering Maico but I don't know about a Yamaha (eh Ford?).I've also ridden Gifford Pichot and remember one extremely tight offcamber slippery rock corner with at least a 250 foot drop on one side.It was during a poker run!
At one of my riding areas there is a bridge over a creek just before a fork in the forestry roads.It was a natural place to stop and take a breather.One of my friends stopped on the bridge and went to put his foot on the ledge but missed and went down 15ft to the creek below and then his RM250 fell on top of him.He was hurt pretty bad.