drm:Only one small section of the trail along the wall gets closed - the part below that horizontal fence, where a larger trail jogs right and connects with a dirt road. You can continue up from there and access the cliff-edge above again.
It's a bit hard for me to tell exactly, where the closures are, but it looks like there are a couple of sections of "wall-side" trail being replaced by a new trail farther east.

The new trail won't have the views of the old.
drm:I think that there are a number of private parcels in the canyon, and I'm just assuming that they bought what was made available by willing sellers.
I'm sure you're correct on this. I can't come up with a better solution; I'll just miss the trail. It makes for a really nice well-rounded loop with trail on top of the wall.
What do you suppose is around that next bend?