Conservationists often argue in favor of preserving tropical forests to maintain biodiversity. Now they can appeal to people's wallets, too. New research suggests that saving tropical forests that are close to coffee crops can lead to increased yields and correspondingly higher profits.

Taylor Ricketts of Stanford University and his colleagues studied a coffee plantation in Costa Rica that is located near a tropical forest. The team assessed the health of plants in three different sections: within 100 meters of the forest, between 700 and 800 meters from the forest, and between 1400 and 1600 meters away from the trees. In a report published online this week by the Proceedings of the National Academy of Sciences, the scientists report that the coffee plants closest to the forest fared best. Higher rates of pollination by bees that live in the forest led to a 20 percent increase in coffee yields in the two nearest plots. In addition, the plants closer to the tropical forest had 27 percent fewer peaberries, or misshapen seeds, which resulted in higher quality coffee.

Using market prices of coffee, the researchers estimated the economic impact of the improved crops. For the one farm that they studied, the researchers calculated that the forest contributed roughly $60,000 a year between 2000 and 2003, or 7 percent of the plantation's total income. Policies that allow landowners to capture the value of pollination and other services," they conclude, "could provide powerful incentives for forest conservation in some of the most biodiverse and threatened regions on Earth.