"Haiti’s Soil Erosion Problem" by Mats Lundahl, Ph.D.
Lundahl is Professor of Development Economics at the Stockholm School of Economics in Sweden. He has written numerous books on the Haitian economy and environment, such as Peasants and Poverty (1979), Poverty in Haiti (2011), and The Political Economy of Disaster (2013).
Haiti has the worst soil erosion in the Western Hemisphere. The "land frontier" that once existed was closed towards the end of the nineteenth century, and the man-land ratio in agriculture has been increasing ever since. As the rural population grows, food crops are planted instead of tree crops, notably coffee, on the steep mountainsides. Over time there is a tendency for the output of food crops to expand and the output of export crops to contract. This is fatal, for coffee is a tree that protects the soil and binds it. Food crops, on the other hand, leave the soil exposed before planting, which happens to coincide with the rainy season. As a result, each year tropical downpours wash away a considerable amount of topsoil from the cultivated mountainsides. Thus, as export crops are replaced by food crops, the risk of erosion increases.
Once erosion has been set in motion, it feeds itself even in the absence of further population growth. As the land is destroyed, more coffee trees have to be uprooted to make room for food production. Erosion is nothing but a reduction of the arable land area, and such a reduction, with a given population, produces exactly the same effect as increasing the population in a given area. Again, the output of food crops, and with that the rate of erosion, increases, while the production of export crops contracts.
The erosion process has exerted a strong downward pressure on peasant incomes for more than a century. Reversing it is not easy. It is costly, and the benefits only show up in the future. It also requires cooperation, for if a single peasant chooses to terrace his land and his neighbors do not, the probability is high that his terraces will be washed away anyway.