People often say that if farmers produced more crops and livestock on their existing land they wouldn’t need to use so much area and could leave more forest. New agricultural practices might also allow them to continue farming their current plots, rather than exhausting their soils and moving to other areas. This logic underlies most Integrated Conservation and Development Projects, which assume that if poor farmers adopt more intensive and sustainable practices they will encroach less on nearby protected areas.

At the regional or national level, agricultural researchers sometimes argue that their work takes pressure off forests by allowing countries to meet their food requirements without clearing additional land. They claim that the only way countries can satisfy their rapidly expanding demand for foodstuffs without bringing more land under crops and pasture is by improving their agricultural productivity.

’Agricultural Technologies and Tropical Deforestation’, edited by Arild Angelsen and myself, represents the first comprehensive attempt to assess these arguments. It presents 18 studies that draw from several disciplines and cover a wide variety of countries, technologies and types of agriculture. The studies deal with everything from pasture research and improved fallows in the Amazon, to the Green Revolution in Asia, the use of chemical fertilizers in Africa, and the reforestation of the southern United States.

The book concludes that under certain circumstances new agricultural technologies do actually benefit forest cover, but they can also have the opposite effect. In particular, anything that makes agriculture in forested areas more attractive runs a big risk of being bad for forests. It may encourage or permit existing farmers to clear additional land or attract new

farmers. Technologies that improve the profitability of activities that do not require much labour, such as cattle ranching or mechanized soybean production, are especially problematic. So is the introduction of new export crops such as cocoa, bananas, and rubber in areas undergoing rapid immigration.

New technologies are most likely to have a positive effect on forest cover when they lead to major declines in agricultural prices and/or require a lot of labour. For example, the rapid rise in rice yields associated with the Green Revolution in Asia reduced pressure on forests by pushing down rice prices, which discouraged upland rice production. Similarly, in areas without much immigration, labour-intensive activities such as growing vegetables, tree crops, and irrigated rice can tie up labour that might otherwise be out clearing more forest. The experience of western Europe and the United States shows that attractive off-farm employment opportunities and effective regulation of forest conversion greatly reinforce the positive effects of agricultural productivity improvements on forest cover.

The bottom line is that conservationists and researchers should not assume that increasing agricultural productivity is always good for forests. Before they make any efforts to protect forests by promoting rural development they should read this book.