Secondly, should forest preservation be found economically optimal, the issue of implementation remains. Since parties that stand to gain from forest conversion to other uses, often do not bear all or most of the related costs, leaving the decision to save or convert the forest up to market forces alone is generally inefficient and sometimes catastrophic. Payments for ecosystem services (PES), to parties with power to convert forest land to other uses, may then be necessary. A further key issue is that, as long as the forested land is not acquired by government or conservation organizations, payments to those who face opportunity costs may be required on a continuous basis. Since long-term continuous payments of this type are unrealistic, a PES scheme for forest protection should usually be viewed as temporary; and as shown by Harstad (2013), to provide no guarantee against the loss of forest in the future.

In cases where payments are needed for forest preservation, for example, to recognize traditional peoples’ historical roles in protecting such forests, obtaining precise values of net forest protection is in many cases extremely helpful, not least to prevent PES implementation payments from being either excessive or insufficient to bring about protection. The main point is that more precise valuation can provide clues to minimum payments that are necessary for the forest to be preserved; alternatively, the maximum payments that are efficient to make to save it.

There are many project-level initiatives underway that attempt to implement PES schemes or in other ways to harness market mechanisms (Wunder et al, 2008), so as to place appropriate economic values on standing forests. Perhaps the most important initiative being considered is Reducing Emissions from Deforestation and Forest Degradation (REDD) in developing countries (hereunder in the Amazon region), and the role of conservation, sustainable management of forests, and enhancement of forest carbon stocks (REDD+). In effect, REDD+ goes beyond PES projects as it focuses on creating both an institutional framework and international financial mechanisms for developing countries to reduce CO2 emissions from deforestation and forest degradation.

The PES literature (Engel et al, 2008; Wunder et al, 2008) and forest carbon policy studies ( _e.g._ Grieg-Gran, 2008) often treat opportunity cost arising from agricultural production parameters as the minimum of what society must be willing to pay for rainforest conservation, so it would serve as a floor cost rather than as a proxy for services precluded. Important issues have here been raised by several authors about the failure to account for other joint benefits of forest conservation that go above and beyond maintaining carbon stocks in forests (Stickler et al., 2009). The danger is then that PES payments will in such cases not be sufficient to prevent forest losses in particular in cases where opportunity costs are “close to” local and regional protection values; payment for the other services provided by the forest may then also be necessary. Borner et al. (2010) estimated a range of opportunity costs throughout the Brazilian Amazon, based on production statistics and knowledge of typical land use cycles. On the other hand, Muradian et al. (2011) suggested that forest occupants at the frontier may be willing at fairly low cost to bring themselves into conformity with a more firmly enforced land-use code, so as to avail themselves of access to institutional resources and avoid penalties. Pereira (2010) discusses two specific PES 7 | P a g e