Matt,
Assume your course had a storm that knocked down a bunch of branches and the superintendent wanted to get things ready for a big tournament that was coming up. He wants to get a chipper in there to mulch up all the branches but he doesn't have time to do it right now. So, he takes the branches and moves them as far into the trees as possible and piles them up for later work, assuming that since these are really good players nobody will hit it over there. It is definitely still his intention to remove them but he has gotten them out of the way for the tournament, he thinks.
It is just because of things like this that officials do silly thinks like marking OB behind a tee where no ball could ever go. Balls go where you don't expect them sometimes.
As for branches that have fallen from a tree but not been piled by the grounds crew. Sorry, you can get some of the patrons to help you move the big ones
but otherwise you're on your own.
In taking relief Ernie had to find the nearest point where he full relief from the pile. Therefore, he is not allowed to have any of the branches in the pile interfering with his swing. He could then drop within a club length of that point. I'm sure he could find somewhere that didn't have any interference from other branches if that is what you are asking.