The Political Economy of Soil Erosion in Developing Countries

The paths to rain forest destruction: Crossnational patterns of tropical deforestation, 1975–1990

Concerns about harmful environmental impacts are frequently raised in research and policy debates about population growth in the hills and mountains of developing countries. Although establishing wildlife corridors and biosphere reserves is important for preserving selected biodiverse habitats, for the vast majority of hilly-mountainous lands, the major ecological concerns are for the sustainability of local production systems and for watershed integrity. What matters for sustained use of those lands not only is the number of producers but also what, where and how they produce. Evidence from empirical research indicates that population growth in hills and mountains can lead to land enhancement, degradation, or aspects of both. This can be explained by extending induced innovation theory to address environmental impacts of intensification. Increases in the labor-land endowment ratios of households and in local land demand and labor supply make the opportunity cost of land relative to labor increase. As a result, people use hilly-mountainous land resources more intensively for production and consumption, thus tending to deplete resources and significantly alter habitats. But, at the same time, capital- and labor-intensive methods of replenishing or improving soil productivity may become economically more attractive, production systems that enhance the land if the expected discounted returns are greater than those of systems that degrade the land. Users will choose production systems that enhance the land if the expected discounted returns are greater than those of systems that degrade the land. In addition to population change, other factors—market conditions, local institutions and organizations, information and technology about resource management, and local ecological conditions—determine the returns from various production systems.

Population pressure and the microeconomy of land management in hills and mountains of developing countries

First principles of the MameLuke multi-actor modelling framework for land use change, illustrated with a Philippine case study.

To assess the role of shifting cultivation in the loss of rainforests in Indonesia, we examined the spatial and temporal dynamics of traditional land-use north of Gunung Palung National Park in West Kalimantan. We analyzed the abundance, size, frequency, and stature (by tree size) of discrete management units (patches) as a function of land-use category and distance from the village. Data were gathered from point samples along six 1.5-km transects through the landscape surrounding the Dayak village of Kembera. Most land was managed for rice, with 5p in current production, 12p in wet-rice fallows (regenerating swamp forest), and 62p in dry-rice fallows (regenerating upland forest). The proportion of land in dry-rice increased with distance from the village; rubber gardens (17p of the total area), dominated close to the village. The size of rubber trees declined with distance, reflecting the recent establishment of rubber gardens far from the village. Fruit gardens accounted for only 4p of the area. From interviews in Kembera and three other villages, we estimated rates of primary forest clearing and documented changes in land-use. Most rice fields were cleared from secondary forest fallows. However, 17p of dry-rice fields and 9p of wet-rice fields were cleared from primary forest in 1990, resulting in the loss of approximately 12 ha of primary forest per village. Almost all dry-rice fields cleared from primary forest were immediately converted to rubber gardens, as were 39p of all dry-rice fields cleared from fallows. The rate of primary forest conversion increased dramatically from 1990 to 1995, due not to soil degradation or population growth but rather to changes in the socio-economic and political environment faced by shifting cultivators. Although the loss of primary forest is appreciable under shifting cultivation, the impact is less than that of the major alternative land-uses in the region: timber extraction and oil palm plantations.

http://www.mekonginfo.org/assets/midocs/0003338-planning-cadastre-the-impact-of-shifting-cultivation-on-a-rainforest-landscape-in-west-kalimantan-spatial-and-temporal-dynamics.pdf

The impact of shifting cultivation on a rainforest landscape in West Kalimantan: spatial and temporal dynamics

Population pressure, expansion of small-scale agriculture and shifting cultivation are commonly cited as the causes of tropical deforestation. A close examination of deforestation and agriculture in the Philippine uplands reveals, however, that the vast majority of agriculturists must be sedentary farmers. In addition, the importance of population pressure as a cause of deforestation in the Philippines cannot be supported by the available evidence. Lastly, the concept of ‘arable land’ is shown to be of limited value in discussing upland agriculture in the Philippines.

D. M. Kummer

Papers

Upland agriculture, the land frontier and forest decline in the Philippines