If you're looking at trees be selective. Conifers have pretty soft top ends and can give a fairly gentle deceleration, the only problem is that leaves you a long way from the ground and getting down is likely to be a bit fraught. However flying into a big oak or maple is going to give a chance of hitting a large branch and spoiling your day.
Water - well if you have any real crash training (like offshore helicopter survival training) perhaps, but as mentioned earlier unless the exits are very direct and all the occupants have a real escape plan then probably not everyone will get out...
I do a reasonable amount of flying over the Scottish highlands which are nothing if not boulder strewn and riven by deep runoff cuts, my cunning plan is to land on the steepest upslope I can find. The forward (and downward motions) are at their lowest and contacting the ground at less than 40 knots (hopefully less than 30!) should make it all survivable. Luckily we have a couple of strips with pretty agressive slopes which helps in practicing the 'flying uphill and landing' technique.