Les services écosystémiques des forêts et leur rémunération éventuelle

Abstract

Forest ecosystem services, particularly those that do not give rise to commodity transactions, have been extensively studied in the last fifteen years so as to characterise, quantify and estimate their monetary value. These studies yield very diverse estimates due to the different types of forests studied, the methods of evaluation used and the content itself of the notion of ecosystem services. We deal with this latter aspect in Part I of the article. After clarifying the differences between ecosystem services, ecological services and environmental services, we show that the notion of “benefits derived from ecosystems”, which is often used to deal with economic assessments of services, in fact covers, particularly in man-managed ecosystems such as temperate forests, contributions that derive both from “ecological capital” and “human capital”. We conclude by underlining, on the one hand, the practical relevance of these distinctions and, on the other, the complexity of the relations between these ecosystem services and biodiversity. Part II presents a summary of available monetary value estimates for services provided by French forests. This summary places special emphasis on the importance of regulation services (carbon fixation, influence on the water cycle and the quality of the water resources, erosion control, etc.) in spite of the fact that we do not currently have estimated monetary values for all of these services. Cultural values, namely recreational ones, also appear on average to be more significant than timber production. In total, all the services evaluated are thought to represent some five times the value of timber production alone. However, this average estimate provides just an order of magnitude for the importance of these services; not only does it integrate just some services and considers use values alone, it furthermore needs to be developed so as to take into account the diversity of local contexts, be they ecological or socio-economic. In Part III, we broach the issue of possible payment ecosystem services; after describing the various possible uses (which in practice are rarely encountered) for these economic assessments of the services, we detail the concept of “payment for ecosystem services” (PES) which can be construed either as a general principle for action (the legitimacy of compensating a service provider in one way or another), or as a specific economic and legal instrument (e.g., and according to the more common definition, as a voluntary, explicit contract setting out the conditions of payment of one or several beneficiaries and one or several suppliers of services who are named). We stress the fact that the number of cases that follow the second definition is very small in practice. Two case studies relating to tropical forests in Costa Rica and Indonesia are then presented, leading us to the conclusion that the evaluation of PES is the outcome of multiple economic, social and political considerations that very rarely include the estimated monetary values of these services as presented in Part II. The concluding section reviews the various controversies relating to economic assessment and the possibility of paying for ecosystem services. It is suggested that a clear distinction should be made between the realms of legitimacy, feasibility and, finally, of applicability. Emphasis is placed on the fact that the road towards effective compensation for these services is no doubt still a very long one.