Bobert, make sure that pine wasn't buried too deep in the pot. That will slow down any tree. The butt swell should show at the surface. Scrape out all of the extra dirt, down to the real roots (not the adventitious sort that sprout when the tree is too deep).

I've had to take dirt away from the bases of several trees here and it has helped. The nursery pots look like they must be okay, so you plant them level, or maybe a little low in the ground, but that isn't good for the tree, and nurseries usually shovel extra dirt on top of the real roots because folks will think there isn't enough root to fool with. You should actually shake off all of the dirt and plant it like it was a bare root tree.

SRS