[u10242]

The most common example I know of is that if in a garden grows an apple tree, where one branch reaches into the neighbor's garden, is the neighbor allowed to harvest the apples from that branch?

IANAL, but IIRC German law states that 1) the neighbor is allowed to harvest the apples and 2) the neighbor can demand from the tree owner to saw that branch off.

[Turing_Machine]

I don't know about the fruit specifically, but I believe that in most jurisdictions in the United States you can also demand that the neighbor remove the encroaching branch, or remove it yourself, if you so choose.

Usually it's better to just be friendly, though. When I used to home brew and grew hops along my back fence, my neighbor on the other side was also a home brewer. I told him he was welcome to any hops that were on his side of the fence. :-)

It probably helped that the fence was old and ugly, and being covered with hop vines make it look nice.

[silisili]

IIRC, in the US, tree law is a lot more complicated (which itself is fascinating).

For example, where I lived, it was my responsibility to trim my neighbors branches that were growing into and falling into my yard. Further, if I chose to cut said branches, I had to make sure it wouldn't harm or kill the tree.