Milling with the grain
Well, that would be the route I'd go. Take a trip to the beach and get something already clean.
Don't expect me to post pics of me dragging a rootball into the ocean.... at least not here in central Indiana.
That hatchet was manufactured that way. It's called a kindling hatchet and the unique shape
makes sense when thought of that way. The curve works really well when shaving off the dirt zone around the buttress, you just have to go around clockwise.
Anyway, I didn't finish answering the question about the actual milling as I got into the preparation, then got lost in my image library as I had to go back a few years to retrieve these photos.
OK, back to milling short stock and buttress wood. (this is the easy part)
Freehand with the longest bar you got. Mill lengthwise, <i>with the direction of the grain</i>, 90 degrees to the normal direction of milling. You can do this because the stock is short. You can get pretty flat with no Alaskan attachments whatsoever, nor even a milling chain. You're gonna get 'woodchips' or 'sawdust' (whatever you wanna call it) that looks like shredded mozzerella cheese, but the cut is fairly smooth, even using regular full-chisel chain.
I've done this many dozens of times because my firewood guys sometimes can't handle a firewood-length of lower trunk, so I'll turn it on it's side and cut it into two halves, and cutting each of those halves in half again creating fourths. Although it generates a large amount of 'bulky' shavings, the newly exposed wet wood pretty much shows off its full character right there on the spot. The procedure is swift because you're working with just the saw, no change to a chain, no attaching a mill setup. Also, cutting <u>with</u> the grain seems to go almost as fast as cutting across the grain. Cutting tangential to the grain (conventional mill ripping) is by far the slowest way to cut through wood.
The pics attached are from a tree where the client wanted the lowest cut possible on the trunk at a 4 inch thickness. Then the next cut, up the trunk at firewood length, cut into fourths to be used as the legs for the table. I have pics here for you of the general procedure, but not a single one of the finished product (that was an oversight, eh?)