I’ve burned a lot of pine, probably 12+ cords worth. It does produce good heat, just not for very long, it’s nice for a short hot fire after work but before bed, and it’s nice for burning down your coal bed. It’s messy with the bark.
One thing is have noticed with my stove at least, is if I have a full load of pine, is it will take off easy, get to 600, see secondaries firing, close the bypass and the stove stalls, staying at about 650-700 and then backpuffs, and it’s a real thick black smoke coming out. And the wood is just charred. Yes, the wood is dry, no, my cat or chimney is not plugged.
The solution I found is it takes a bit more fussing with the stove, and getting it hotter before you close the bypass, and keeping it hot.
The only thing I can think of is maybe it takes a bit more to ignite the pitch, or that thick of black smoke overwhelms the cat, who knows. I know that the boxelder, quaking aspen, ash, pin cherry, black cherry, apple, dogwood, locust and mulberry from the same stack, stacked at the same time, with the same moisture content don’t require as much fussing.
It may be that the pines I do cut around my place are standing dead/laying dead, and died from a pine beetle or blight, so maybe that makes them have more pitch.