It may be counter intuitive but treetops are actually ‘soft’.
They bend and absorb energy over a fairly long period compared to other ground
obstructions. I would favor landing in dense trees over a field full of stumps
and rocks.
It is well known in the glider community that tree-top
landings result in pilots that walk away and surprisingly light aircraft damage
as long as the plane maintains flying speed all the way in. I have personally
picked up after two of these and know of four others. In only one case was
there any injury to the pilot and that was minor. Dense trees are preferred
because falling to the ground after the ‘landing’ is where the
people can get injured.