Stihl, was that helmet out of date??? Looks very brittle to have smashed like that. Problem with helmets breaking apart like that is they allow the object to continue through. A fibreglass helmet (like pacific) even though breaks, remains together to hold out and "bounce off" the object.
Think of it like the glass on cars. On the side you have toughened which just shatters, where the front windscreens are laminated to stop object (to a degree) going thru.
By holding the safety barrier together (whether it be glass or helmet) the safety object itself does not become a danger in itself.
Me, helmets...in trees or on bikes...not worth the risk. Say safe.
