The potential use of papyrus (Cyperus papyrus L.) wetlands as a source of biomass energy for sub-Saharan Africa

Four of five people in sub-Saharan Africa rely on the traditional use of solid biomass, mainly fuelwood, for cooking. In some areas, the current rate of fuelwood consumption will exhaust biomass reserves within the next decade or two. A largely unrecognized source of biomass are tropical wetland ecosystems which have been shown to be some of the most productive ecosystems globally, exhibiting rates of net primary productivity comparable with high-input, intensively managed agricultural systems. Papyrus (Cyperus papyrus L.) is an emergent sedge with C-4 photosynthesis which is native to the wetlands, river valleys and lakes of central, eastern and southern Africa. The mean standing dry matter of culms and umbels measured at a number of locations throughout East Africa is 38.3 +/- 21.6tDMha(-1), and the aerial net primary productivity ranges between 25.9 and 136.4tDMha(-1)yr(-1). Papyrus vegetation can be harvested by hand and stacked on the rhizome mat for partial air-drying, and it has been demonstrated that an annual harvesting regime has no negative impacts on long-term productivity. The use of papyrus as a biofuel for cooking and heating depends on converting it to a suitably combustible form, such as compressed or carbonized briquettes with a calorific value approximately one-third less than wood charcoal. While papyrus has significant potential as a biofuel, we argue that an integrated management and decision-making framework for the sustainable utilization of papyrus wetlands is required, in which all ecosystem services including the provision of biomass energy need to be assessed. Sustainability of papyrus wetlands requires management which combines the strength of traditional communal governance and modern legislation to promote its utilization. In this way, local communities can benefit from the inherent advantages of tropical wetlands as very productive ecosystems.