Something's chipping up a dead tree

While walking in my woods I noticed this tree.  It is a fairly large tree and is dead, but something appears to be chipping away at it in a major way.  You can see that the trunk has been chipped away quite a bit and there is a pile of chips on the ground.

Here's a view of the tree from the side to the right of the first picture.  The chipping is somewhat uneven with some deep furrows.

Here is a closer picture of the bottom front of the tree, where you can see the degree of damage and the chips on the ground.

Here is the bottom from the side.  You can see some of the furrows.  It almost looks like claw marks on the bottom portion.

Here's the middle section from the front.

And the middle section from the side.  Here you can really see the deep furrows.

Here is the top portion from the front.

Here is the top section from the side.  The only thing that I can think that would do this would be woodpeckers, and particularly the large pileated woodpeckers.  Still, even with the big woodpeckers, it seems like an awful lot of destruction.  I don't visit this part of the woods often so I don't know how long this has been going on.