Large areas of the warm, humid tropics in Southeast Asia, the Pacific,
Latin America, the Caribbean, and Africa are hilly or mountainous.
Jackson and Scherr (1995) estimate that these tropical hillside areas
are inhabited by 500 million people, or one-tenth of the current world
population, many of whom practice subsistence agriculture. The region
most affected is Asia which has the lowest area of arable land per
capita. Aside from limited areas of irrigated terraces, most of the
sloping land, which constitutes 60% to 90% of the land resources in many
Southeast Asian countries, has been by-passed in the economic
development of the region (Maglinao and Hashim, 1993). Poverty in these
areas is often high, in contrast to the relative wealth of irri- gated
rice farms in lowland areas that benefited from the green revolution.
Rapid population growth in some countries is also exacerbating the
problems of hillside areas. Increasingly, people are migrating from
high-potential lowland areas where land is scarce to more remote
hillside areas. Such migra- tion, together with inherent high population
growth, is forcing a transforma- tion in land use from subsistence to
permanent agriculture on fragile slopes, and is creating a new suite of
social, economic, and environmental problems (Garrity, 1993; Maglinao
and Hashim, 1993).