The timber exploitation in the department of Imperial between 1867 and 1920 is analysed for the first time, taking into account the causes of this exploitation, the form in which the wood was harvested, and the environmental consequences of this activity. Primary sources (records and writings from travellers, government officials and naturalists, among others) and secondary sources (primarily historical, archaeological, and paleo-environmental studies) were analysed for this purpose. The results show that i) the forest was exploited due to constructive, ideological, and profit related motives, ii) the wood was extracted using traditional methods, for example, by hand and with the aid of oxen, and iii) the destruction of the forest lead to the loss of biodiversity, to micro-climatic changes and to the unusual flooding of rivers, due to riverbed silting, as a result of the deforestation.