This study explores how the impact of large scale plantations and their associated industrial operations can be evaluated. It takes a value chain approach, looking at impacts on suppliers, customers and stakeholders such as communities, local and national government and investors. Whilst there is renewed interest from investors, governments and enterprises in the potential of planted forestry operations in Africa, doubts have been expressed by communities, and environmental and socially orientated NGOs about their impacts. This paper seeks to provide a framework which can be used to examine the impacts of modern plantations in Africa, given that the context can be very different from plantations in temperate regions. An impact logic (theory of change) is developed which sets out the range of activities, stakeholders and intended impacts, based on two cases of investments in sustainable forestry operations in Tanzania and Mozambique. This, a literature review and interviews with stakeholders, guided the development of indicators to assess economic, social and environmental impacts. The extent that a quantitative and qualitative (mixed methods) impact evaluation is possible and the data required to enable such an evaluation are deliberated. An evaluation framework and supporting indicators are proposed and discussed.