Trees must think people are arseholes.
Think about it, just look at the whole thing from the perspective of a tree.
There are people walking aroud, seemingly minding their own business, and then one day some arsehole comes up to your old friend Billy the tree and sprays some mark on his nice jacket and walks away like nothing happened. And you say,'Hey! Hwo's cleaning this up? How's Billy supposed to feel all paited up like this?'. Some time later on, when you've almost forgotten about the whole thing a human shows up with a saw and cuts poor Billy down...
This is cold...
Like.. you know.. squirells all look the same to us, humans (I'm human btw), we must all look the same to the trees too, right?
Imagine the fear trees must live in.. Now go there and show them we're not all like that, not all people are heartless tree killing nazis.