Shifting cultivation has been considered a major cause of deforestation and forest degradation many times over by both by scholars and conservation agents. Thus, the adoption of permanent agriculture is advocated as an environmentally friendly alternative, allegedly because it will allow the intensification of land use and the set-aside and protection of forest reserves. The Guinea-Bissau case, however, shows that complex bio-cultural landscapes existed under shifting cultivation and that it was precisely their conversion into permanent agroforests of cashew nuts that triggered fast deforestation and a country-wide homogenization of the landscapes.
Links between shifting agriculture, agrobiodiversity and cultural diversity
This small West African country presents a great diversity in ethnic groups, languages and dialects and agroecological conditions, making it a perfect place to study bio-cultural diversity. Until recently, the interweave of people and ecology produced a diversity of farming systems—different combinations of multiple shifting cultivation practices, mangrove swamp rice cultivation, inland swamp rice cultivation, orchards and homegardens—and landscapes. Diverse bio-cultural landscapes were created under smallholder farming; different ethnic groups had different farming practices—highlighted by dissimilar combinations of cropping systems—and diverse cereal preferences, clearing and burning techniques, length of cropping and fallow periods, tools and cattle integration in agriculture. Regional agroecologies are also important in defining the possible combinations of cropping systems and the most cultivated crops. Farmers made use of the diversity of the micro-ecologies at hand, combining cropping systems of varying degrees of intensification and challenging evolutionary views of agricultural change.
The recent increase in deforestation is not a result of the depletion of soil fertility by a growing population of shifting cultivators. In our research, analysis of the R values (number of years of cultivation multiplied by 100 and divided by the length of the cycle of land utilization) clearly proves that a degradation-induced deforestation is not occurring. On the contrary, degradation can be attributed to a sudden process of agricultural intensification—measured by the time a field is under cultivation and not by the amount of labor or external inputs used—started at different times and rates across the country, after structural adjustment measures (mid-1980s) to increase export revenues.
Homogenization of landscapes into simple cashew agroforests
Independent of the region and of the previous characteristics of shifting cultivation practices, farmers all over the country are converting shifting cultivation fields into cashew orchards, creating an agricultural frontier. Mostly since the civil war (1998–99), every field slashed-and-burnt is converted into an orchard and—according to farmers—this will continue until all village’s and households’ forest reserves are gone. The expansion of the agricultural area due to fruit production has been facilitated by customary rules of access to land and relative land abundance. Moreover, traders go to rural areas and exchange cashew nuts for imported rice.
By 2009—through smallholder agriculture—Guinea-Bissau was the world’s second largest exporter of raw cashews and achieved the largest per capita production. Complex agroecological matrixes combining different vegetation cover types, diverse agricultural fields corresponding to different cropping systems and the successional forests of fallow fields are being converted into simple agroforests of cashew trees, interspersed with a few trees of other species. Thus, agroforestry agricultural intensification, instead of allowing for the stabilization of the cultivated area, is entailing extensification and the destruction of more sustainable and biodiversity rich, mosaic-like landscapes that existed under shifting cultivation practices. Furthermore, by rendering this low-labor intensive agriculture lucrative, cashew plantations encouraged a scramble for land by both rural and urban actors and increased pressure upon the remaining woody areas. The resulting privatization and commoditization of commons has had negative social and environmental consequences.
Reforesting old orchards and returning to agroforestry systems
Since 2007, the exchange rate of cashew nuts with imported rice has been decreasing. At the same time, new areas of forest are being cleared to create new orchards (increasing production compensates for the drop in the price of nuts), and some old, less productive orchards are being allowed to regrow with natural vegetation cover. However, farmers with no land reserves, have started to slash-and-burn old cashew orchards to allow the production of food crops again. At this point, cashew orchards then can be integrated into permanent alley-cropping agroforestry cultivation of food and cash crops and/or can start to act as planted fallows.
Indeed, farmers are starting to perceive that the rapid land use cover changes described above have perverse consequences. This could be a major opportunity to introduce reforestation measures in old cashew orchards and to protect remaining woodlands, through participatory multi-disciplinary research and landscape-based approaches. However, the national institutional environment constitutes a major constraint upon the willingness of farmers to adopt reforestation or even reduced deforestation and forest degradation measures and to accept the creation of new protected areas.Marina Padrão Temudo is a research fellow at the Tropical Research Institute (IICT) in Lisbon, Portugal, and a senior research associate at the African Studies Centre, Oxford University, UK. She has conducted extensive ethnographic field research on development & conservation in Guinea-Bissau, Cape Verde, Mozambique, S. Tomé and Príncipe, and in the Republic of Guinea.