Many mixes from the south contain pine. Pine is very acid. You never want to see southern pine in your mix. Terrible stuff. Unless you are building a house. Then it is wonderful wood to use, right up there with Douglas Fir. Wonderful big money wood.
You do no want it though. The other additives are there to try to take out the acid from the wood by products you are getting. The bark and maybe needles off the trees, scrap from the mills. Way high acid.

Another thing you would have to look out for is the soil going more to the acid side after time. As you water you may notice your ph dropping as the buffers they are adding to combat the pines acids wash off. Perlite and vermuculite anr neutral ph.
Bottom line. I would not go near it.
Dr. Bloor Reviewed by Dr. Bloor on . My soil good to use? IN CALIFORNIA AND GEORGIA, THIS MIX CONTAINS 68%-72% SPHAGNUM PEAT MOSS, VERMUCULITE, AND PERLITE AND LESS THAN 1% FERTILIZER AND LIME FOR PH BALANCE GUARANTEDD ANALYSIS Total Nitrogen (N) 0.09% 0.04% Ammonical 0.05% Water insoluble Available Phosphate (P2 O5) 0.05% Soluble Potash (K2 O) 0.09% F-1431 :dance::gunfighter2::chainsaw: Rating: 5