The impact of shifting cultivation on a rainforest landscape in West Kalimantan: spatial and temporal dynamics

Abstract

To assess the role of shifting cultivation in the loss of rainforests in Indonesia, we examined the spatial and temporal dynamics of traditional land-use north of Gunung Palung National Park in West Kalimantan. We analyzed the abundance, size, frequency, and stature (by tree size) of discrete management units (patches) as a function of land-use category and distance from the village. Data were gathered from point samples along six 1.5-km transects through the landscape surrounding the Dayak village of Kembera. Most land was managed for rice, with 5p in current production, 12p in wet-rice fallows (regenerating swamp forest), and 62p in dry-rice fallows (regenerating upland forest). The proportion of land in dry-rice increased with distance from the village; rubber gardens (17p of the total area), dominated close to the village. The size of rubber trees declined with distance, reflecting the recent establishment of rubber gardens far from the village. Fruit gardens accounted for only 4p of the area. From interviews in Kembera and three other villages, we estimated rates of primary forest clearing and documented changes in land-use. Most rice fields were cleared from secondary forest fallows. However, 17p of dry-rice fields and 9p of wet-rice fields were cleared from primary forest in 1990, resulting in the loss of approximately 12 ha of primary forest per village. Almost all dry-rice fields cleared from primary forest were immediately converted to rubber gardens, as were 39p of all dry-rice fields cleared from fallows. The rate of primary forest conversion increased dramatically from 1990 to 1995, due not to soil degradation or population growth but rather to changes in the socio-economic and political environment faced by shifting cultivators. Although the loss of primary forest is appreciable under shifting cultivation, the impact is less than that of the major alternative land-uses in the region: timber extraction and oil palm plantations.