Seven decades (1950–2020) of tree planting campaign in the tobacco production areas of Tanzania: an insight from land cover/change survey

Abstract

Tobacco cultivation in Tanzania is frequently linked to deforestation, increasing the risk of desertification and land degradation. To mitigate these effects, decades-long afforestation campaigns have been implemented. However, the effectiveness of these efforts remains understudied, which hinders our understanding of their sustainability and replicability. This study explored the efficacy of these afforestation campaigns, usually conducted in woodlots by analyzing seven decades (1950s to 2020s) of changes in land use and land cover (LULC) in Urambo, Uyui, and Kaliua districts, which are the leading tobacco production areas. LULC classification relied on open-source data and software, utilizing Quantum GIS and Landsat imagery for 2000 and 2020, as well as country’s topographical maps of 1956 and 1976. This study adopted cadastral surveying coupled with digitization of satellite images to estimate area cover of woodlots. The study revealed a 62% decline in forest cover from 28,985 in 1956 to 8,811 sq. km in 2020. This decline is largely due to population growth, which has increased demand for land for settlement and shifting cultivation, leading to more bush and grassland. However, afforestation campaigns have deemed ineffective, as the total area reforested (455 out of 32,715 sq. km) is significantly less than the annual rate of forest loss (315 sq. km per year). The inefficiency of afforestation efforts is partly attributed to the widespread planting of eucalyptus trees, an exotic species that offers limited benefits to farmers, making it an unpopular choice for wood production, including tobacco curing. This study highlights the importance of using productive species Gmelina arborea (beechwood tree) in woodlots, implementing clear fallow periods, and efficient harvesting cycles in plantation forests to ensure regeneration and maintain a balanced ecosystem.