I don't know anything about the history of your country. That being said, I would suggest you get a topo map and mark all the places you have carvings and look for some type of pattern. Do some research and find the old trails and roads and see where they are in relation to your carvings. You live in an area where there has been a lot of recorded history. Your carvings could mean anything. Especially something like an arrow that would be a common direction indicator. I used it a lot when I was a kid to keep from getting lost in the woods. A fish could mean a good fishing hole. A cross could mean an intersection or it could be a religious symbol. A lot has happened in your country and if you think your carvings might be related to something of value it's going to take a lot of research to find out how the signs tie in together.
Rick