The proposed launch of a Reduced Emissions from Deforestation and Degradation (REDD+) scheme by the UN Framework Convention on Climate Change provides a new incentive to improve global forest monitoring. By evaluating the state-of-the-art in government and scientific monitoring this paper shows that enhancements and new standards are needed for three key monitoring roles - measurement, reporting and verification - for governments at national scale and scientists at global scale. It outlines a new knowledge exchange matrix framework that can match different organizations to monitoring roles. Conversion of data into useful knowledge is represented by a knowledge exchange chain comprising a series of cycles, each divided into data collection, information production, reporting, verification and synthesis stages. Each stage potentially involves operational, facilitating and coordinating functions at local to global scales. Combining stages, functions and scales forms the knowledge exchange matrix. Organizations are matched to cells in the matrix by their competence and rules governing their operation. Applying the matrix to global forest monitoring shows that existing organizations can contribute complementary facilitating and coordinating functions to support REDD+. Yet none can harness satellite data operationally to produce information at the required spatial and temporal resolution. Two empty national and global operational niches could be filled by new national measurement, reporting and verification systems, operated by governments and facilitated by the Group on Earth Observations and other bodies; and an autonomous science-based World Forest Observatory whose information base could advance global change science and help to verify national REDD+ reports.