Even with relatively low participation rates, the PES program appears to have been an effective and cost-effective way of averting carbon dioxide release.
Take-up: Program take-up was relatively low, at 32 percent, even though the program was designed to be simple and low-risk for landowners (farmers would not receive payments if they cut down trees, but there were no other commitments or penalties). Qualitative interviews suggested that two-thirds of individuals who did not sign up were simply unaware of the program or faced logistical problems in the sign-up process. A small minority said that they did not sign up because they were not interested in the program.
Payments: The average landowner who participated in the program received the equivalent of US$113, approximately 80 percent of the maximum amount they were eligible to earn. The bulk of payments (89 percent) were for avoiding deforestation, rather than for planting new seedlings.
Effects on deforestation: Despite the relatively low number of participating landowners, the program resulted in significantly less deforestation in the villages were it operated. While tree cover in the comparison villages declined by 9.1 percent in the comparison villages over the course of the study, this number was 4.2 percent in the villages with the program. This resulted in an estimated cost of US$0.46 per ton of carbon delayed from entering the atmosphere, roughly half of the social cost of carbon—the overall negative economic impact of carbon pollution on society —which the United States Environmental Protection Agency estimates to be US$1.11 per ton for the delay induced by the program. By comparison, programs designed to reduce pollution such as subsidizing electric cars or providing incentives to upgrade to more efficient appliances can cost more than ten times the social cost of carbon emissions they avert.
Unintended effects: Some fear that PES programs only appeal to landowners who would have kept their forests intact without the program or that they cause landowners to shift tree cutting to other lands. Researchers did not find evidence for either of these concerns., In fact, the program appeared attract landowners who would have had higher rates of tree-cutting had they not been in the program, and satellite data showed that participants did not shift tree-cutting to other areas by colluding with their neighbors or by cutting down trees on areas not covered by contracts.
Effects on households: The program was financially neutral for most participants, as there were no increases or decreases in expenditures or borrowing. The program led landowners to patrol their own land more often, and they became less likely to allow landless neighbors to gather firewood on their property (even though collecting fallen wood was allowed). As non-landowners are generally poorer than landowners, the program may have had a negative impact on poorer members of the community.