Prosopis infestation along the Fish River in southern Namibia poses a considerable threat to the environment; in particular, it reduces the water flow/water yield in the river. In this paper we propose that the trees be removed and utilised as firewood, which would also generate an income to the local community. For this, an average wood biomass per tree size class is established, and the total harvestable wood biomass for the Gibeon area (about a 5 km river stretch at Gibeon) is estimated to be as much as 2,900 tons of wood. Harvesting for firewood alone will not curb the infestation, though. Saplings and coppice from the felled stumps need to be removed as well. It is suggested to treat felled stumps with arboricides applied directly to the stumps. Foliar application and/or soil application of arboricides are not recommended, due to the danger of these leaching through the soil and either contaminating the water in the Fish River and/or killing trees from the natural vegetation. Gradual removal of Prosopis, combined with active revegetating of the natural vegetation is also recommended for the river bank area. In this way the natural vegetation can be replaced, without threatening the bank through erosion. Overall, this long-term project should be developed as a public-private partnership between the community of Gibeon (and other communities along the Fish River) as well as the Directorates of Forestry, Hydrology and Water Environment of the MAWF. Keywords: Alien invasive control, fire wood harvesting, wood biomass.