Neighbor's tree - Security and dirt. Who is responsible?

I do not see the branches as dangerous. Dirt is nature. At least one tree is sick. Just talk to a tree removal service. 1) decides how sick the trees are 2) how dangerous - so that a tree does not fall during the next storm 3) they know the legal basis 4) they can specify the costs A concession on the costs from your side might be a basis for a conversation

We had a similar situation, an ancient neighbor's tree had always extended over its property line; nobody cared for a hundred years until we came and built. Only when the house was finished did I notice that a few strong branches were growing towards our gutter. I talked to the neighbor and he commissioned the trimming, I paid. He was only afraid of the costs. Money CAN SOMETIMES help. Now we do that every 5 years. After all, the tree had been there long before any of us were born. Humans don't have to push back all of nature, sometimes you can accept it and let it continue living...

Section 910 of the Building Code, paragraph 1, applies here. Set a reasonable deadline. This can also be quite long depending on which vegetation period the tree is in. If nothing happens, you can start and also charge the owner. Distance rules could also be an issue. Even if the green space office/forestry office determines that a tree is rotten and must be felled... I would first try to have a conversation and "cautiously" point out the legal situation. If they obstruct, nothing will come from the neighborhood anyway. Then you can pull out all the stops.

Section 910 of the Building Code, paragraph 1 applies here. Set a reasonable deadline. This can also be quite long depending on which vegetation period the tree is in. If nothing happens, you can start and also charge the owner. Distance rules could also still be an issue.

... and then charge the neighbor according to Section 1004.

Distance rules no longer apply here in NRW. This should have been addressed at the latest six years after planting (Neighborhood Act NRW).

Hahaha........You are really great. So, dear community, here is the solution! So it only avoids "eternal disputes" as long as you do it in the neighbor's absence? In which yellowed mediation brochure could you read that? :D Wonderful........ Criminal liability is only a very small part of such a topic.

Well, if he's not there, maybe he doesn't even notice? I once read that the part that extends onto my property may be removed by me.

Well, if he's not there, maybe he won't even notice?

That would definitely be an option in case of existing visual impairment. But if not, there will be even more complaining.

I once read that the part that extends onto my property may be removed by me

Sure, the problem is always with "being right and getting the right," or the collateral damage in neighborly relations.
You only ever know if it was a good idea afterwards :D