Bamboo charcoal is a thing and has been used in east Asia for a long time. It has many uses, including water purification and as fuel source. It burns hot and long like traditional coal/charcoal. I think it would be a huge benefit to the game, especially for players in hot climates with limited access to tree. The current stop gap is to cut down fern trees for firewood but there is no current way in survival to make fern trees renewable. Having the ability to make bamboo charcoal would go a long way towards making the tropics more engaging.