Cheaper Robusta varieties of coffee are often grown by clear cutting areas of indigenous vegetation and replacing the native species with non-native coffee plants. More expensive Arabica beans grow better under a protective canopy of trees. Growing coffee under that protective canopy results in coffee that can be labeled "shade tree."
Traditionally, all coffee was shade-grown. Most varieties of coffee produce better when grown in partial sun. However, a hybrid was introduced in 1972 that would grow and produce well in full sun. By clear-cutting large swaths of tropical rain forests, planting these varieties of coffee allowed commercial growers to produce very large harvests with very low costs. However, the environmental damage caused by this form of coffee production resulted in the introduction of the marketing name "shade-tree coffee" to describe coffee produced using more environmental-friendly techniques.
There are a number of ways to cultivate shade-tree coffee. Among the traditional methods, the rustic method uses natural canopy trees and mid-level trees to shade coffee trees that grow in cleared areas in the taller forest. Traditional polyculture adds other tall trees, like bananas or other crop-bearing trees, into the natural canopy to help shade the coffee. By planting using this method, a farmer can grow two crops in the same space. Commercial polyculture removes the tall, natural canopy trees, leaving only the mid-height trees and other crop trees to shade the coffee. Although technically still shade-grown coffee, removing the canopy trees harms many of bird and wildlife species.
By leaving the natural canopy and overstories in place, coffee growers can help maintain habitat for many birds, songbirds and other wildlife. By shading the soil and adding leaves to the soil as natural fertilizers, shade-grown coffee also reduces the need for artificial fertilization, thus making the soils healthier for ground-dwelling plants, insects and animals.
Effects on Coffee
By growing coffee under shade trees, the beans mature more slowly. The bean's natural sugars increase, making the coffee more flavorful. Because the older and more flavorful Arabica beans grow only in shade, most shade-grown coffee are these larger and more valuable beans.
The only plant that generally receives more chemical pesticides than coffee is tobacco. Because shade-grown coffee can benefit from natural pest predators and from the natural fertilizers dropped to the ground by surrounding plants, birds and animals, many shade-tree coffee growers are switching to organic coffee production, thus reducing the use of artificial chemicals and pesticides.