This presentation examines the local innovation history of the Bena people in post-colonial Tanzania, focusing on utilization of non-native trees. By the late 20th century, Bena villagers adopted planting trees on farmland as a key strategy to ensure food security and improve household income. To address land shortages, reduce reliance on chemical fertilizers, and diversify their economy, they planted fast-growing trees like non-native acacia and pine. For mutual support, the Bena relied on "mgowe", a reciprocal labor system, to cope with the shortage of male labor due to frequent migrant work. Through this practice, the knowledge and skills of forestry were widely shared, and mgowe contributed to the establishment of the swidden agroforestry.

Over the last 15 years, their farming system has been increasingly diversified by introducing various new commercial tree crops (e.g. avocado, tea and eucalyptus). The farmers, especially the youth, have taken new strategies. Former residents who had been working or studying in urban areas are returning, drawn by opportunities in forestry-related businesses and avocado cultivation. There is a growing reliance on hired labor for agricultural work, and participation in mgowe has become less frequent. In contrast, new collective efforts have begun to appear in avocado farming, with mutual financing group members jointly managing shared plots. Also in tea farming, with close relatives and neighbors organize small-scale labor exchange.

The Bena people have intermittently improved their farming systems and succeeded in riding out the vagaries of socio-economic situations caused by the changes in national politics and market. In this process, they have collectively attempted to plant unfamiliar trees, generating and sharing knowledge. This presentation examines how non-native trees have been adopted and how planting knowledge has been shared and transmitted under conditions of economic globalization and the emergence of more plural and dynamic community forms.