Originally, coffee farming was done in the shade of trees, which provided habitat for many animals and insects. Today, farmers use sun cultivation, in which coffee is grown in rows under full sun with little or no forest canopy. This causes berries to ripen more rapidly and bushes to produce higher yields but requires the clearing of trees and increased use of fertilizer and pesticides. Opponents of sun cultivation say environmental problems such as deforestation, pesticide pollution, habitat destruction, and soil and water degradation are the side effects of these practices. The American Birding Association has led a campaign for "shade-grown" and organic coffees, which it says are sustainably harvested. While certain types of shaded coffee cultivation systems show greater biodiversity than full-sun systems, they still compare poorly to native forest in terms of habitat value, and some researchers are concerned that the push for "shade grown" coffee may actually be encouraging deforestation in ecologically sensitive regions.