CHUK101, A lot depends on your location. A lot depends on what you carry in your pocket. A lot depends on the situation.
If you are in the woods in the NJ PineBarrens vs an Oak forrest in the Appalachians, different materials present themselves for use. Always carry a good pocket knife. "Don't leave home without it"
I would not recommend using pine tar glue in any situation ... will eventually gum up the barrel, and make it a beast to clean once you are back to civilization.
Are you talking about a "damn, I can get a squirrel, but ran out of darts" ... or "I am totally lost, need to survive, need food now" ? If the latter, then pine tar be damned - go ahead and use it.
The Cherokee (in Cherokee, NC .. a restored 1700's village with re-enactors) use hardwood spints, about 17 inches +/- long, with about 3 - 4 inches of "fluff" for a plug. That can be thistle-down, or rabbit fur, deer fur, dog hair, etc. Enough to plug up the dart in the barrel, but not too much so it can't be effectively shot out. It takes time and practice to make, and learn by trial and error, just how dense to make it, how thick (diameter) to make it, how far of a set-back from the tail to start it (like an arrow, there is a "nock" left for handling), and how long to make it. From what I have seen (and sadly, I was there before I got involved with competition blowgun shooting, otherwise I would have asked more questions, watched more closely, and learned), they use a wrap method, more akin to atttaching fletching to an arrow shaft. Compacting and making the plug smooth and an even diameter for its entire length. They do not make them on the fly, as you are asking about (not even the indigenous americans in the Amazon area do that), instead, they make a large supply to carry with them in a quiver, when they run out, they get more materials and make a bunch more. In their culture, this is an expendable item.
Natural dart materials are EXTREMELY difficult to shoot. They don't behave like our man-made materials (whether you are talking store-bought tailcones on wire or bamboo skewer darts, or tail cones made of rolled paper or plastic on bamboo skewers or other long sharp pointy objects (aluminum nails, knitting needles, etc.)
I hope this helps.