Well hysterical is absolutely appropriate in this case because hysterical can also mean out of your mind or crazy. Usually it happens to people when something noteworthy actually happens to them like a mother's child drowning or somebody else close to somebody has just died, unlike in this video. That's the way I meant it, but it is a pun as well, so it's even more fitting.
Trees are not people. Anybody on their hands and knees crying out into the air and screaming about fallen trees is clearly hysterical.
And a little weird is an understatement. Those people clearly have some very disturbing psychological issues.