This chapter explores the transformations caused by the 1920s coal boom in Tonkin, especially with respect to forests and the ways in which they were exploited. Demand for mine timber soared during this period, since coal mining enterprises required a large number of mine props to support their underground tunnels. With hard timber becoming a highly sought-after commodity, illicit timber exploitation and trading networks began operating under the radar of French colonial surveillance. Taking advantage of this mining-driven high demand for timber, Chinese, Vietnamese, and Dao loggers and traders exploited and sold hard timber to large-scale coal mining companies, often without permission. Forest rules were flouted in a frenzied search for mine timber. This chapter underscores how capitalist developments, such as coal mining, were the main perpetrators of the destruction of timber forests in Tonkin, as opposed to indigenous swidden farming practices. This story of coal mining and deforestation also demonstrates the adaptability of indigenous networks, the internal weakness of colonial rule, and the ecological consequences of unchecked capitalist developments.