Introducing and terminating monetary incentives in non-regenerating forests: Insights from a framed field experiment

In regions with low soil fertility, smallholder farmers often clear forest to sustain agricultural yields. This pattern becomes more problematic where forest regrowth is slow, contributing to local forest loss and global environmental challenges such as climate change and biodiversity decline. This paper presents findings from a framed field experiment that examines how different types of monetary incentives affect forest-clearing decisions in northern Namibia, a semi-arid region with negligible forest regrowth. We implemented a common-pool resource game with 518 smallholder farmers across 25 villages, in which a forest stock declines dynamically based on participants' clearing decisions, without immediate regrowth. The game spans three periods: a baseline without incentives, an intervention period with individual or collective rewards or an individual fee, and a post-incentive phase. This setup allows us to assess both the immediate effects of incentives and their persistence after incentive removal. All incentive types reduce clearing compared to the baseline, but not significantly more than in the control condition, where clearing also declined - an unexpected trend likely linked to features of the dynamic game design. Incentive effects largely dissipate after removal, with no strong evidence of lasting motivational crowding-in or crowding-out. Overall, our results suggest that moderate payments may be insufficient to sustain cooperation in persistent resource dilemmas. More broadly, they highlight the importance of multifaceted analysis including control conditions and careful experimental framing in field-laboratory studies, coupled with caution in generalizing findings to other settings or policy applications.