Land system science, the inter-disciplinary study of the processes that shape how land and natural resources are used, is essential to solving major societal problems such as climate change, poverty, and food insecurity. This PhD thesis presents innovative remote sensing and spatial statistical techniques to understand pathways and processes of cropland and tree plantation expansion in the emerging frontier of Northern Mozambique, where large-scale land acquisitions for commercial agriculture have risen sharply over the past two decades. The empirical results of this research improve understanding of where large-scale land acquisitions are occurring in the region, the conditions in which land acquisitions consolidate smallholder cropland or encroach upon natural vegetation, and how cropland and tree plantation expansion are impacted of Mozambique’s land tenure policies and practices. The methodological findings of this research demonstrate new approaches to mapping smallholder cropland, large-scale commercial agriculture, and tree plantations using freely available software and satellite imagery. As Mozambique and many other countries ramp up efforts to mitigate climate change and promote rural economic development by investing in new tree plantations, this research shows that it is critical to monitor not only plantation expansion, but also the expansion pathways and land use trajectories to better understand the social, economic and environmental impacts of tree plantation expansion.