I’ve experienced this pitch filled from splits of pine, you have to be careful as it goes off like a nuclear reactor.Fatwood is generally a thing from the southeast--Georgia and thereabout--from southern yellow pine.
But I harvest it here in Colorado from Ponderosa Pine stumps. Not every stump by any means. But frequently the stump remaining after I remove a Pondo has pine pitch oozing from it in copious quantity within a day or two. Kids go to sit on a bright, fresh stump and are practically glued to it.
Don't know how it works, but years down the line certain of those stumps are preserved, barkless, and quite heavy. I split them up small, and every piece glistens with pitch and smells like turpentine. You don't want to put a sizable chunk in the stove or you'd overfire it something terrible. I put a chunk about the size of my fist in the stove recently and the stove was cranking hot, making noises I didn't like, black smoke pouring from the chimney--and that's from wood that has seasoned many years.
I keep some around for firestarter--one match to a piece of it will serve in place of a fistful of kindling. I've given away several boxes and buckets of this stuff to friends. Pretty fancy stuff.
Even when you throttle the air down to nothing it’s hard to slow down.