I *think* I know the answer (although I'm not a dog-owner). I believe the human intends to remove the poop back on the way back thru.

^ Which is un-fucking-acceptable. Carry it with you, in another bag if necessary. Can't or don't want to handle this responsibility? Don't get a dog.

Congratulations! You've just made the 1,000th I,ANONYMOUS dog-poop-bag post. Your prize is, you guessed it, 1,000 brightly-colored bags of dog poop (pick them up at the Mercury office during normal business hours).

Those are not bags. Those are little fuzzy sweaters required for PDX Dog Poop Fairy pick-up.

I,m so glad people take their dogs out for walks and nature. The bags are being used to expand drug deals and are decoys. Sometimes money is in the bag.

Seeing poop-bags along the trail certainly takes away from the beauty of a hike.
Being a dog-owner myself, it seems to me the best ecological answer is to throw the stuff over the side of the trail in the bushes where it can decompose easily, instead of putting it in plastic.