Encouraging the reconversion of rubber plantations by developing a combined payment system

Abstract

Rubber (Hevea brasiliensis) has been introduced to Southeast Asia for over a century. In various regions throughout Southeast Asia, over the past two decades, natural tropical forests have rapidly been converted into rubber monoculture. To encourage the reconversion of rubber plantations back to close-to-nature rainforests, we developed a theoretical combined market and government payment system. To evaluate the potential impacts of the system, we carried out a simulation study from 2020 to 2050 in Xishuangbanna, Southwest China. The results suggest that the payment system may encourage a total reconversion area of 198,490 ha with a total government payment of US$0.377 billion in net present value (NPV) by 2050. The total carbon sequestration benefit resulting from the replacement of rubber plantations would be 14.83 million tons of carbon over the modelled period. Sensitivity analyses revealed that rubber price was the most sensitive factor on the total NPV of compensatory payments, and followed by the discount rate. The rubber price increased by 96.8% could enhance the compensatory payments in NPV by 272%, whereas a 10% decrease in the discount rate resulted in a 18.9% increase of the compensatory payments in NPV. This new integrated payment system holds the potential of stimulating restoration of cash crop monoculture-dominated landscapes to multifunctional forest ecosystems.