アイテム詳細

要旨

Tropical forests are key components of the global carbon cycle given their considerable carbon stocks. Agriculture is often seen as in major conflict with tropical forests, with carbon budget models highlighting dramatic carbon stock losses with the conversion of land for food. However, these models often focus on monocultural cropping systems, while the archaeological and historical records highlight more varied forms of food production in tropical forests from at least 8,000 years ago. Here we develop a simple model to simulate relative aboveground carbon (AGC) values for a tropical forest anthrome with varied food production practices. We examine past examples of tropical land use activities including understory thinning, selective agroforestry and various swidden patterns. We compare these to old-growth forests, open cropping and plantation systems. Results highlight the importance of retaining large trees to AGC. Understory thinning practices have a limited effect on AGC by mainly impacting small trees. Regular, short fallow swidden drastically reduces AGC, while irregular, long fallow swidden can maintain AGC half that of old growth forest. A mosaic landscape of forest food production can maintain much higher long-term mean AGC values than is typically assumed for carbon budgets of past land use.