I just saw a post where it was suggested that "nature doesn't have wood chippers". Rather than derail that thread, I figured it would be interesting to start of list of nature's wood chippers.
Here are two I'm quite familiar with:
I've seen wood chip piles from pileated wood peckers bigger than this one:
And our friends the beavers do a bit of chipping as well:
Are there other wood chippers you know of?