Planting Trees in Oil Palm Plantations: Results from a Randomized Controlled Trial

Palm oil expansion in Indonesia is associated with both a reduction in biodiversity and ecosystem services, and livelihood improvements for smallholder farmers. While this dichotomy highlights the importance of sustainable management options, empirical evidence on which policies are effective in stimulating biodiversity-friendly plantation management is relatively scarce. This paper addresses this gap by presenting results from a Randomized Controlled Trial implemented in Jambi province, Sumatra, in 2016. We focus on tree nuclei planting in oil palm plantations as one sustainable management option. To test whether information and input provision affect smallholders tree enrichment activities, two treatments were designed: the first provided information about tree planting in oil palm, while the second combined information and input delivery. We model adoption in a double-hurdle framework where farmers first decide whether to adopt or not and then how many trees they plant per hectare. Our results suggest that both interventions are effective in stimulating tree planting in oil palm. While input provision in combination with information leads to a higher probability of adoption, farmers plant on average relatively few trees per hectare. In contrast, in the informational treatment, few farmers enrich but they plant more trees per hectare than farmers who received saplings. Acknowledgement : We thank the Deutsche Forschungsgemeinschaft (DFG) who funded the data collection in the framework of the collaborative German-Indonesian research project CRC990.