with my limited knowledge of law, I would think that a tree on a piece of land is part of the land.
When Sannich got this land, it got everything on it, in it and underneath it. Sannich should be responsible for the nuisance the tree caused.
And they say they have confirmed that they didn't plant the tree, if it is confirmed, they must know who plant the tree, you can probably ask for proof of the confirmation.
Good luck!
I think VIRCS has free legal aid too, check on that.