Do I have to notify the neighbor about building the fence?

PS: The deer was there again.

Actually, I can just build the fence now - I don't even have to notify anyone, right?

If §7 (2) is fulfilled, that's probably the case. Is your fence so elaborate that moving it would be a big deal; and how much longer will the neighbor remain a farmer (after all, he gets more for building land than for grain) ?

Well, it's 150m of fence. You don't want to do that twice. I can't say what the farmers are planning. One wants to sell, but he is the nicest of them all.

Naive question: Can't you just protect your trees? There are also options for that. It seems easier to me than building fences meters long.

Well, it is also a 100m long hedge that is newly planted. In between are the trees. Everything is still very delicate and small. The deer doesn't care whether it's a bush or a tree. It brushes everything away. We have already protected the big trees a bit. But I can't possibly wrap the whole hedge. Only with a game fence around the entire property.

Whether you need to inform someone now or not, just do it – as a matter of courtesy.