An index of ‘deforestation pressure’ is suggested as useful for reserve planning alongside the currently used information on the species present at candidate sites. For any location, the index value is correlated with threats to habitat and thus also survival probabilities over time for members of species dependent on that habitat. Threats in the absence of reserves are key information for planning new reserves. The index is estimated using a regression approach derived from a dynamic, micro-economic model of land use, with data on observed clearing of forest over space and time as well as biophysical and socioeconomic factors in land returns. Applying an estimated threat (or probability of clearing) function for Costa Rica to locations of interest yields relevant estimates of sites’ deforestation pressure, which are used to evaluate proposed reserves and to suggest other candidate sites.
G. Arturo Sanchez-Azofeifa, Gretchen C. Daily, Alexander Pfaff, Christopher Busch
Biological Conservation 109 (2003) 123–135
The transformation and degradation of tropical forest is thought to be the primary driving force in the loss of biodiversity worldwide. Developing countries are trying to counter act this massive lost of biodiversity by implementing national parks and biological reserves. Costa Rica is no exception to this rule. National development strategies in Costa Rica, since the early 1970s, have involved the creation of several National Parks and Biological Reserves. This has led to monitoring the integrity of and interactions between these protected areas. Key questions include: ‘‘Are these areas’ boundaries respected?’’; ‘‘Do they create a functioning network?’’; and ‘‘Are they effective conservation tools?’’. This paper quantifies deforestation and secondary growth trends within and around protected areas between 1960 and 1997. We find that inside of national parks and biological reserves, deforestation rates were negligible. For areas outside of National Parks and Biological reserves we report that for 1-km buffer zones around such protected areas, there is a net forest gain for the 1987/1997 time period. Thus, it appears that to this point the boundaries of protected areas are respected. However, in the 10-km buffer zones we find significant forest loss for all study periods. This suggests that increasing isolation of protected areas may prevent them from functioning as an effective network.
Suzi Kerr, Shuguang Liu, Alexander Pfaff, R. Flint Hughes
Journal of Environmental Management 69 (2003) 25–37
Policy enabling tropical forests to approach their potential contribution to global-climate-change mitigation requires forecasts of land use and carbon storage on a large scale over long periods. In this paper, we present an integrated modeling methodology that addresses these needs. We model the dynamics of the human land-use system and of C pools contained in each ecosystem, as well as their interactions. The model is national scale, and is currently applied in a preliminary way to Costa Rica using data spanning a period of over 50 years. It combines an ecological process model, parameterized using field and other data, with an economic model, estimated using historical data to ensure a close link to actual behavior. These two models are linked so that ecological conditions affect land-use choices and vice versa. The integrated model predicts land use and its consequences for C storage for policy scenarios. These predictions can be used to create baselines, reward sequestration, and estimate the value in both environmental and economic terms of including C sequestration in tropical forests as part of the efforts to mitigate global climate change. The model can also be used to assess the benefits from costly activities to increase accuracy and thus reduce errors and their societal costs.
The fuel-use decisions of households in developing economies, because they directly influence the level of indoor air quality that these households enjoy (with its attendant health effects), provide a natural arena for empirically assessing latent preferences towards the environment and how these evolve with increases in income. Such an assessment is critical for a better understanding of the likely effects of aggregate economic growth on the environment. Using household data from Pakistan we estimate Engel curves for traditional (dirty) and modern (clean) fuels. Our results provide empirical support for a household production framework in which non-monotonic environmental Engel curves can arise quite naturally. Under plausible assumptions about the emissions implied by fuel use, our estimates yield an inverted-U relationship between indoor air pollution and income, mirroring the environmental Kuznets curves that have been documented using aggregate data. We then demonstrate, through a simple voting model, that this household-choice framework can generate aggregate EKCs even in a multi-agent setting with heterogeneous households and purely external environmental effects.
Suzi Kerr, Alexander Pfaff, G. Arturo Sanchez-Azofeifa
Central America Project, Environment: Conservation and Competitiveness. HIID 2001. Chapter 15.
In this chapter we consider potential gains derived from preventing deforestation, drawing heavily from information from Chapter 14. It uses the same economic model and econometric technique and the same land use/land cover data. It also uses the carbon stock estimates presented there. The key difference is that, instead of using proxies for land-use returns such as ecological characteristics related to higher productivity, we attempt to directly estimate dollar-valued returns. We use these as an independent variable to explain and predict deforestation patterns. This allows us to simulate the potential supply of carbon sequestration in response to dollar-valued returns for certified emissions reductions. Payments for CERs will reduce deforestation by lowering the net return from forest clearing. The loss of the reward for carbon sequestration will partially offset the positive return from agricultural uses. To estimate the effect of such payments on deforestation, and hence CER supply, we need to estimate the response of deforestation to changes in returns to land use. An increase in agricultural returns is empirically equivalent to a reduction in carbon CER payments. Thus, we construct a variable that estimates the potential return of a plot of land if it is cleared. We construct a variable that varies across space (different crop suitability and yields) and time (changes in export prices, technology, and labor costs). We then use this variable in our econometric estimation. The results are used to calculate a supply curve of CERs. These results are illustrative only. They are produced as part of an ongoing effort at estimation (Kerr, Pfaff, Hughes et al. 2000) and are used to show some underlying features of a dynamic supply curve.
Suzi Kerr, Alexander Pfaff, G. Arturo Sanchez-Azofeifa, Marco Boscolo
Central America Project, Environment: Conservation and Competitiveness. HIID 2001. Chapter 14.
The chapter is structured as follows. First, below, we begin this analysis of the process influencing land changes with a dynamic model of land-use choices. Such models have often been suggested, but crucial features have often been neglected in application. This model generates testable hypotheses regarding factors underlying patterns of land-use changes in tropical areas. The next section describes the data collected for this project and discusses the quality of land-use data. It also outlines the variables used to test the implications of the model. Following that, we present our results and then discuss the linkage from land-use changes to implied carbon sequestration, and the quality of information currently available on carbon sequestration. Finally, we present some conclusions and lessons learned.
An index of ‘deforestation pressure’ is suggested as useful for reserve planning alongside the currently used information on the species present at candidate sites. For any location, the index value is correlated with threats to habitat and thus also survival probabilities over time for members of species dependent on that habitat. Threats in the absence of reserves are key information for planning new reserves. The index is estimated using a regression approach derived from a dynamic, micro-economic model of land use, with data on observed clearing of forest over space and time as well as biophysical and socioeconomic factors in land returns. Applying an estimated threat (or probability of clearing) function for Costa Rica to locations of interest yields relevant estimates of sites’ deforestation pressure, which are used to evaluate proposed reserves and to suggest other candidate sites.