Assessing benefits and opportunities from tree planting in the southern agricultural growth corridor of Tanzania

Abstract

Ecosystem restoration is seen as essential for conserving forests, preserving biodiversity, and addressing climate change. However, achieving e ective and equitable restoration requires integrating social considerations to better understand and manage trade-o s that arise from these interventions. This thesis addresses the need for a more inclusive approach to tree-cover restoration by examining methods that incorporate local perspectives and preferences into restoration planning. Firstly, I map the global evidence on participatory scenarios in ecological restoration to understand their role in assessing trade-o s across restoration outcomes. The findings suggest that participatory scenarios enable the integration of diverse knowledge types and methods, yet their impact on restoration planning remains unclear. Then, through participatory scenarios with smallholder farmers and a sentiment analysis, I explored farmers' preferences and attitudes toward tree-cover restoration in Tanzania’s Kilombero Valley. Farmers' desired outcomes diverge from current restoration policies and plans that emphasise exclusionary protected areas, underscoring the importance of participatory planning approaches that align with local aspirations. Lastly, I investigate how homegarden agroforestry and sugarcane contract farming contribute to household resilience to climate change. Both farming strategies can positively and negatively a ect livelihood resilience as smallholders grapple with trade-o s from limited land, costs of planting and maintaining, and risks to livelihood outcomes. Farmers have cleared trees from their plots for sugarcane, leading to a concentration of farmers' trees within homegardens, suggesting that homegardens may be important for ensuring the direct benefits of trees for smallholders and conserving aboveground carbon stocks. Overall, this thesis argues that agroforestry o ers a promising strategy to enhance livelihood diversity and resilience. However, achieving equitable restoration requires recognising and addressing the trade-o s and preferences of all stakeholders. I advocate for a broader methodological approach that combines diverse data types and participatory methods to ensure that tree-cover restoration e orts align more closely with the needs and values of local communities.