This doesn't always mean much. I don't have a good example right now, so I just use this GIF from Beyond:
http://abload.de/img/beyond1d4s7v.gif
I would say the amount of detail and the artistic direction in there is pretty good for a scenery that lasts exactly as long as the GIF (3 seconds) and you never see again. I wouldn't be surprised if the forest area in SS only appears in
this cutscene (and the other one in the car) and maybe a tutorial.
Perhaps Sucker Punch operates in a totally different way and only adds detail when the area is actually playable? I don't know. Again, I would love to be wrong, good, non-linear and lengthy forest areas are pretty much impossible to find these days. We will see and hope for the best I guess...