I kidded just a bit when I've talked about having tried something out in my "Backyard Test Jungle," but the truth of it is, I was only half-kidding.
It is a jungle out there. (Cue jungle sounds, monkey screeching, Tarzan yell, etc.)
While I didn't find a pine stump, I did find a section of a fallen branch that looked likely, so I decided to run some test.
First off:

This pic was taken just as the report came back,
"Positive Cat Scan for fat lighter'd!" AKA: Fat Wood. And tell me you didn't see that "cat scan" coming a mile of!)

Lab report won't be in because I don't have a Lab. Got an Aussie, just no water dogs in the area.
Took a cut off one side:

And then the final test:

That's ones kind of fuzzy, but the black smoke is pretty much a give-away. When the cut was made, I was rewarded with a very heavy, turpentine smell.
I'll prob'ly cut this up into maybe 4 inch pieces and then splitting those into quarters or smaller, depending on the thickness. It really doesn't take much of this stuff to get a blaze going.
And the other "treasure" I recovered was this:
Wasn't sure it was "punky" enough, so I cooked some up and gave it a try. Works just fine!
In the tinderbox:

That downed oak was a small one, only about 8 inches in diameter. But there's a section of it that I'm hanging on to, about 10 feet long or more. Should be able to keep that tinderbox filled for some time to come! And that's not counting what can be picked up on the trail. . .
I'll be keeping some char cloth in my fire kit, just because its so easy to use. But I think I'll keep it back, for "just in case." I'll be depending upon the char punk for fire starting, as it is a material I'll never have to worry about running short on. I'll consider the char cloth to be a "luxury" item.
Since I've started on this "fire-making kick," I've become something of a pyromaniac (again.)

Personally, I consider it to be very useful, but its also one heck of a lot of fun!
Mike S.
Spring Hill, FL