A small but interesting category!
Tools of this type have many different names, to name just a few: Spud, Bark Spud/Iron Peeling Spud/Iron.
Bark Peelers (as we'll call them!) can greatly facilitate the removal of bark from green logs. Removing bark will slow down the decay process and give the wood a much longer life as water and dampness will be shed quickly and not linger hastening the rotting process. Also removing the bark makes it less attractive to wood boring weevils and the like.
The blade of a Bark Peeler slides between the bark and the wood. The best time of year to remove bark is in the spring and early summer when the sap is rising and the bark will fall away with very little effort and leave a clean smooth uncut surface. Ideally, peel the bark soon after felling.
If you have to remove bark from large older logs that were winter felled, the bark may feel superglued to the log. In this case you may need to remove as much bark as possible with a long handled Bark Peeler then finish off with a wide drawknife. In this instance there will inevdivably be tool marks remaining on the log surface.
I first heard of oak bark peeling when I first met Coppice Merchant Bill Hogarth MBE. Bill died in 2000 and used to spend 3 months every year peeling bark from coppiced oak, selling it to the high class leather tanning industry. Effectivly, Bill used to sell two products from the same cut piece of oak; the bark to the tanning industry and the peeled rustic poles to rustic outdoor furniture makers. During the bark peeling season his hands were constantly stained black.