One potential use is for the production of iron. Before the 1700s, when coke was discovered, ironmaking furnaces exclusively used charcoal 1,2 in production. This charcoal is generally produced by burning wood in a low oxygen environment. While in principle you could use bamboo or other organic sources to produce the charcoal, given the strategic importance of iron it may be that there simply isn't enough bamboo production to meet iron needs.

One potential use is for the production of iron. Before the 1700s, when coke was discovered, ironmaking furnaces exclusively used charcoal in production. This charcoal is generally produced by burning wood in a low oxygen environment. While in principle you could use bamboo or other organic sources to produce the charcoal, given the strategic importance of iron it may be that there simply isn't enough bamboo production to meet iron needs (charcoal production for iron was a significant source of deforestation in the US according to here- depending on your settings requirement they may face similar shortages)

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