On this video, I tried out a simple (albeit not very efficient) method of producing birch tar glue that I read about in the July edition of the magazine "Spektrum der Wissenschaft":
https://www.spektrum.de/magazin/derk...

It is really as simple as it gets: Burn some birch bark next to a smooth rock. The evaporated oils will condense on the cool surface (and sometimes drip down onto the ground beneath the fire), from which they can be scraped off and collected. This provides a good model for how early humans might have discovered this material in the first place.

The yield is very low, though: All I got was the two little boogers of tar shown in the video. With more advanced methods, it is possible to get substancially more tar from the same amount of bark. I plan to try those as well, once I have a more regular access to a fireplace.

Also check out this video on the same topic by the channel Neanderthal Joe:
   • Three methods for  Birch tar glue Nea...