Interaction effects between economic development and forest cover determine deforestation rates

Recent work on global patterns of deforestation has shown that countries with high per capita GDP or low remaining forest cover are more likely to be experiencing afforestation than deforestation. Here, I show that the relationship is more complex than previously described, because the effect of one variable is dependent upon the value of the other. As a result, high-income nations exhibit the opposite response to disappearing forest cover than low-income nations. In an analysis of 103 countries, I found that high-income countries with low forest cover have the highest rates of afforestation, typically through the establishment of new plantations. In contrast, low-income countries with little forest are more likely to consume that remaining portion at a faster proportional rate than do low-income countries with more forest. Nations with large amounts of forest have approximately equal deforestation rates, regardless of national wealth. These results highlight for the first time that there is a strong interaction between forest cover and economic development that determines rates of forest change among nations. (C) 2006 Elsevier Ltd. All rights reserved.