I have 4 acres of planted loblolly (yellow) pine that is about 20-25 years old, and occasionally burn some. It hasn't been my main heating wood since I usually get enough oak and beech from storm damage, but I would probably burn more pine if the other wood wasn't as readily available.
The thing I have noticed with the loblolly is that it's very wet and sappy when green. Much wetter and heavier than other pines (we have some Virginia white pines here, but they are scarce). Seems to take longer to dry than hardwoods from what I have seen. I either burn standing dead loblolly, or make sure it has a good 2 years to season after being split. I can tell by the weight of a split piece if it's ready to burn.
Just last week I cut down a standing dead loblolly that must have been killed by beetles. The top half was dry and ready to burn, but the bottom half was heavy and wet, so I threw it on my wood pile for next year or the year after.
I have a nice 20" loblolly log that I saved to mill into lumber, mainly out of curiosity. Hope to get to it in a few weeks. I normally mill oak, poplar, cypress, and walnut, but thought I'd give the pine a try to see how it looks. In this area, the loblolly is mainly planted for pulpwood, since we are surrounded by several big paper mills.