Property lines and cutting down trees are serious matters with very strict laws. That’s why you should always do your research before you even want to cut down plants, even if they appear to be on your property. For example, this person who cut down a tree on the property line of their house and their neighbor’s, but now the Washington government wants to fine them. Who is responsible will depend on which property the tree was on.
Redditor beanbaz shared on r/treelaw photos of several cut trunks. Just seeing the picture, you can see that it was a huge tree. According to what OP describes, the neighbor was building something on their side. But it seems that the tree was in their way, so they had to cut it down. The real problem is that a letter came from the city government in Washington, to determine which side of the property line the tree they cut down was on, to determine who to fine. The fine would be for not having a permit to cut the tree and would be $80K.
The implication is that if the government determines that the tree was on OP’s side of the property, they will be fined even though they did not cut it down. So OP is very concerned, because they are very sure that the tree was on their side. Something that user GumpTheChump found ridiculous when they wrote: “I don’t understand. In what universe would you be responsible for someone removing your tree without your permission? Does your city simply go after the homeowner regardless of culpability?“.
The best chance that OP could have, and that some comments pointed out, is to prove that it was the neighbor who cut the tree. Some photo, video, or even trying to contact the contractor who cut the tree would be crucial evidence. Others say OP should contact a lawyer just to protect themselves in a worst-case scenario. But according to BoozeTheCat, it won’t be that easy, as they said, “I worked code enforcement for a time, and shit was always directed at the landowner, regardless of the responsible party.” So OP will need to face a civil suit against the neighbor after the fine.
Honestly, it’s silly that OP can’t prove his case before they get fined, but if that’s the case, hopefully the lawsuit against the neighbor won’t take as long or take more money.