I had a large scotch pine that died in a field the furtherest from my house.  A neighbor to the field asked if he could have it for firewood in his shop.  He cleaned it up nicely, I like those things that are win-win, I got rid of the tree, he got firewood.  He told me later he had to burn the split wood outside at a weiner roast, it was worthless in his pot-belly stove.  He said the stove almost melted down, got all red hot, from pine tar burning.  I should have known that, but didn't think to tell him.  Later, my stepsisteer married a guy in Georgia.  They burned wood, but would not bother touching any pine tree, it was worthless wood for heat, burned too fast and too hot.  I do use a small amont of pine at times if I have a branch come off, a stick makes the rest of the oak or other hardwood start fire faster in my fireplace.