Integrating smallholders into formal and increasingly global commodity chains is seen as a means to address rural poverty and unemployment. However, this process can have highly differentiated and uneven outcomes for farmers and produce new forms of vulnerability and risk. This thesis focuses on high-value tree crops such as macadamia and avocado grown by smallholders in a former homeland in South Africa, as policymakers consider these commodities to have the most potential for rural job creation and income generation. Situated in the Marxist tradition of agrarian political economy, this thesis foregrounds the accumulation and differentiation processes and how these (re)shape smallholder trajectories and agrarian social relations. It shows that smallholder tree-crop farmers are highly differentiated. A small minority are well-positioned individuals with off-farm income investing in tree crops, resulting in a steep and rapid accumulation trajectory. This is increasingly linked to the de-facto privatisation of customary land and growing inequality in land access, which signals a transformation of customary land governance in the face of a commodity boom. Most smallholder tree-crop farmers do not have access to off-farm income and demonstrate how limited, yet incremental accumulation is possible via agricultural diversification into vegetable cash crops. Counter to mainstream policy thinking, it is the latter group that should be the focus of agrarian policy to achieve broad-based opportunities for rural livelihood creation. The findings imply that land and agrarian reform policy should focus on facilitating a broad-based accumulation of this latter group rather than on a small class of capitalist farmers.