molasses, is added, to a lot of plantys that are consumable, to alter the taste,,, harshness,,,sourness,,,e,t,c.
and even to help some mediums to grow certain picky plants better,
i think, it has something mainly to do with the sugar in the molasses,,
ive never used, it, but have read, a lot about it's use, in many different plants for multiple reasons,
I would agree with that Chicken, I've planted quite a few white pines, I swear by putting about 2 liters + 1 cup of sugar in the hole when I put the root ball in, it's always worked well for me, not sure why but it does. (mixed the sugar/water together in a homogeneous mixture first)