It's a real thing, but it's often a thing lawyers like to joke about, in that it exemplifies how ridiculously complex the law is, in that there's a field of law about a very mundane object everyone has seen, but you don't think about a lot.
Every municipality has their own laws on trees and how liability is determined when it comes to trees. And trees are not completely confined to borders. Sometimes, the roots of one tree go into another municipality or state, sometimes the branches hang over another, sometimes, a tree that's in one town falls down into another... tree lawyers are basically there to know who's liable and what the law says for every one of those situations, and many other things.
It's a real thing, but it's often a thing lawyers like to joke about, in that it exemplifies how ridiculously complex the law is, in that there's a field of law about a very mundane object everyone has seen, but you don't think about a lot.
Every municipality has their own laws on trees and how liability is determined when it comes to trees. And trees are not completely confined to borders. Sometimes, the roots of one tree go into another municipality or state, sometimes the branches hang over another, sometimes, a tree that's in one town falls down into another... tree lawyers are basically there to know who's liable and what the law says for every one of those situations, and many other things.
It's a great example of how common law systems are completely insane bullshit written down by extremely unserious people.
You see the same sorts of things in civil law systems, too.