So I was walking through the wilderness and I saw this: The player in the background of the first picture did not do it. He died and was running back to get his stuff. I'm not even sure if this was a grief of the protected spawn or a glitch or lag with my internet. However if it is a grief of the protected spawn then I suggest moderators, and admins look into this to see how it could have been done and how to prevent it.
This is not the correct way to report a griefing, you need to PM a mod. However, this simply looks like the effects of lighting (or fire off it) or similar - completely natural and not caused by a player.
I know I just wasn't sure if it was a grief or not. I don't have evidence of someone doing it so a report wouldn't do much good either.
I repaired some of the trees, as Jack said, it is very likely lightning strikes. The protection in town and in the spawns are pretty ironclad and impenetrable.