While Sub-Saharan African countries are increasingly vulnerable to climate change, they also face lower marginal cost for carbon reduction. Existing studies point to payment for ecosystem services (PES) as a way of incentivizing reforestation, but it remains unknown whether market-based payment structure affects the cost-effectiveness, and if so, how it relates to heterogeneity in participants' beliefs. In this project, we investigate the cost-effectiveness of different PES policies for shade tree planting by cocoa farmers in Ghana, considering target population's heterogeneous beliefs about climate change risks and adaptation benefits.