In Kwilu, forested areas are gradually moving farther away from villages over the decades, mainly because the local farming community does not engage in reforestation after exploitation. As a result, forests are under strong pressure from the cutting of trees, shrubs, and saplings. This phenomenon, long observed in Africa and elsewhere, illustrates the unsustainable exploitation of forest resources. Firewood and charcoal play a major role in meeting domestic energy needs, particularly in Sahelian countries where they account for a very large share of energy consumption, as well as in the Democratic Republic of Congo. To ensure sustainable management of forest resources, it is necessary to balance exploitation with stock renewal. This requires knowledge of the total and gross primary productivity of forest stands, that is, the growth rate of forest products in relation to the intensity of photosynthesis.