Since you've helped me get on the right track, I found people used a combination of green and dry strips of bark and a core of an easily combustible material that keeps a constant supply of tinder furnished to similar torches in the west, used to further light larger torches soaked in a flammable substance.
These were apparently replaced with beeswax coated twine which burned slowly.
I also found that strips of Bamboo and River Cane were used extensively in the prehistoric past for cave exploration. That is short bundles of burned, bundled cane were found in caves, apparently what was left of a hand held portion of the torch as it burned down too short to be held.
To make one of these torches they just bind up a bundle of River Cane or Bamboo strips and light them and blow them out, the 'tinder' that lights the embers is the strips of the torch beaten fine enough to catch fire easily. The top (that is seen being thrown away in the images above) kept the air supply low to keep them smoldering till the fire was needed.
This method was also used in making brushes :