Ultimately, the objective of a REDD scheme is to scientifically, technologically and financially support developing countries to install policies and measures that reduce deforestation and degradation. To ensure verifiable emission reductions, effective forest monitoring systems must be installed in participating developing countries. These systems will have to combine remote sensing imagery and field data. A particular difficulty for developing countries will be to establish an effective and cost-efficient system to monitor and assess the progress that has been made in the different activities that are eligible under REDD.