Now, wait a minute! Why would anyone ever want to get rid of woodchips? This feels like a personal attack on me. (Only kidding.)
Seriously, I would start with my carpenter's slick.
A slick is a LARGE, heavy chisel, perhaps 4 inches wide, weighing in at least 5 pounds with the cherry handle I made for it. It is close to 3 feet long with that handle, with a blade that is perhaps 3/8 inch thick. You can find them in old tool sales for a reasonable price.
The nice thing about a slick is it has some serious mass behind it. So despite seeming a large cumbersome thing, you can use it with the bevel riding against a wall, and it would probably glide right through those woodchips and peel off a strip of paper. That mass allows for a surprising degree of precision in getting a smooth result. I've used it to peel up flooring once and it did a very nice job.
And, when I was all done, I would give the slick some loving attention, and touch up any nicks I've left in the blade.
If this did not work, I'd go pick up my angle grinder.
Skim over the surface of the paper lightly, using a structured carbide disk that will cut through and carve wood like butter. With a gentle touch, I'll bet you could do this without even giong into the plaster underneath. Wear a dust mask though. Having done that in strips, the steamer will now have an easy avenue to get under the paper. So much for woodchips. :(