I often ponder this as I flit between power lines and trees...
I think if it came to actually landing in trees, I would get the tail going into them first, then maybe allow it to flop forward. The reason for this is a friend of mine went into the trees in a normal attitude and ended up with the cyclic in his middle (no spleen now) as the blades hit. Also, there is more of the machine between you and them. Of course on the day it will be different, but where I can, I fly from clearing to clearing or at least note the ones to try for every 5 secs or so.
Don't forget, the object is to walk away, so don't worry about the machine.
Phil