Background information / Coffee and the environment

What is shade-grown coffee?

Coffee (Coffea sp.) is a small understory tree or shrub, and has traditionally been grown amongst forest trees, in the shade. Various studies indicate that arabica coffee has the highest yields under 35 to 65% shade. In addition, growing coffee under shade also discourages weed growth, may reduce pathogen infection, protect the crop from frost, and helps to increase numbers of pollinators which results in better fruit set. Coffee grown in the shade takes long to ripen and is often thought to taste better because the long ripening times contribute to complex flavors.

However, in order to produce faster, higher yields and prevent the spread of coffee leaf rust (Hemileia vastatrix), many coffee plantations began to grow coffee under sunnier conditions. The fewer shade trees that are in coffee plantations, the less biodiversity there is in those plantations.

This loss of biodiversity, especially in birds, has led conscientious consumers to look for “shade grown” coffee.  However, coffee is grown under a continuum of conditions, from rustic or traditional, to full sun, and these “shades of shade” are not all equal when it comes to the health of ecosystems. Unfortunately, there is no official definition of “shade grown,” so coffee so labeled may be grown under what are technically shady conditions, but which are little better full  sun.

Categorizing types and levels of shade

It is important to understand the various levels of growing coffee under shade. Here are the five most typical categories, from the most desirable, traditional growing method, to the least diverse, most modern and technified method.

  • Rustic. Often used on small family farms. Coffee is grown in the existing forest with little alteration of native vegetation. Tree species are diverse, with an average of 25 species. Shade strata (layers of vegetation) three or more. Shade cover = 70-100%.
  • Traditional polyculture. Coffee is grown under a combination of native forest trees and planted tree and plant species, including fruit and vegetables both for the farmer and for market, fuel wood, medicinal plants, etc. Common tree species under which coffee is frequently grown include Inga, Grevillea, Acacia, Erythrina, and Gliricidia. Shade cover = 60-90%.
  • Commercial polyculture. More trees removed in order to increase the number of coffee plants, and shade is provided mostly by planted timber and fruit trees. Canopy trees are regularly pruned, and epiphytes are typically removed. More often involves use of fertilizers and pesticides due to the lack of vegetative cover which helps prevent loss of soil nutrients, etc. Typically only two vegetation layers, the canopy, and the coffee. Shade cover 30-60%.
  • Shaded monoculture. Dense plantings of coffee under an overstory of only one or two tree species (usually Inga), which are heavily pruned. Epiphytes are removed. Shade cover = 10-30%.
  • Full sun. Lacks a tree canopy, or has a few isolated trees. No shade cover.

And here is a diagram from a paper by Patricia Moguel and Victor Toledo [1] to help you visualize the categories:

As you can see, coffee grown in a shaded monoculture could technically be labeled “shade grown,” but it would probably not be what the consumer, concerned about biodiversity, is looking for.

Benefits of growing coffee in the shade

The post “The problems with sun coffee” outlines some of the negative environmental impacts of growing coffee in the sun. Here are some of the benefits of growing coffee in the shade:

  • Shade coffee supports biodiversity, and farms can act as wildlife corridors between plots of natural habitat. Numerous studies have shown that the diversity of birds, orchids, bats, ants, amphibians, bees, beetles, spiders, mammals, and other taxa are higher in shaded coffee than in sun coffee.
  • Shade coffee provides pollination services, increasing the fruit set of coffee itself, as well as other plants on the farm.
  • Shade coffee farms have a higher diversity of predators that help control coffee pests (just a few examples of research here, here, and here).
  • Shade coffee typically has fewer weeds. Weeds often require more sunlight and are also controlled by the natural mulch supplied by fallen leaves from the shade trees.
  • Nitrogen-fixing trees on shade coffee farms enrich the soil, as do the fallen leaves from the shade trees.
  • Soil erosion is reduced in shade coffee, also improving soil quality.
  • Shade coffee farms have more stable microclimates and can buffer against temperature and humidity fluctuations caused by climate change.
  • Coffee grown in shade can improve quality.
  • A diversity of shade trees can provide other economic benefits to farmers.

The Smithsonian Migratory Bird Center has developed standards that are targeted specifically at shade management and preserving biodiversity; their certification is called “Bird-Friendly” (this is a trademarked term and should always carry the Smithsonian seal). More on their criteria here. The Rainforest Alliance has a certification program for coffee that has an array of environmental standards, although shade cultivation is not a requirement. Their optional criteria is compared to the Bird Friendly criteria here.

See also Rice, R. 2010. The ecological benefits of shade-grown coffee: the case for going Bird-Friendly. Smithsonian Migratory Bird Center.

[1] Biodiversity Conservation in Traditional Coffee Systems of Mexico. 1999. Conservation Biology 13:11—21.

Background information / Coffee and the environment / Corporate coffee

The problems with sun coffee

Two species of coffee are grown commercially. Coffea canephora, or robusta coffee, is an often bitter species that is usually considered low quality and is used as a filler in cheap grocery store coffee. The higher quality arabica coffee, Coffea arabica, is an understory tree or shrub which naturally grows in shade. However, mostly with an eye toward profit, there has been a movement to find ways to grow arabica coffee in the sun.

Coffee is grown on nearly 10 million hectares in tropical regions around the world, areas that also harbor high levels of biodiversity. In the 1990s, farmers were encouraged to replace traditional shade grown coffee with sun cultivation in order to increase the yield of their coffee. In sun coffee systems, there is little or no canopy cover, and coffee trees are planted at high densities. In Latin America, 1.1 million of the 2.8 million hectares in coffee (41%) were converted to sun cultivation (Rice and Ward 1996). The impact of deforestation and conversion of shade coffee to sun coffee on biodiversity in these regions is much greater than the absolute levels of destruction would indicate.

While older arabica coffee varieties traditionally grown in the shade did not do well in the sun, they were replaced by hybrids that could withstand the sun and had more resistance to introduced diseases. But sun cultivation also has many other negative environmental impacts:

  • In shade plantations, dead leaves from the overstory trees provide nutrients to the coffee.  In sun plantations, these nutrients are not available, so fertilizers must be used, especially nitrogen (since many traditional overstory trees are nitrogen-fixing legumes). Sun coffee farms leach triple the nitrates into the local watersheds than shade farms.
  • There are fewer weeds in shade plantations, both because of the shade itself and due to the fallen leaves from shade trees acting as a natural mulch.  Herbicides are needed to control weeds in sun plantations.
  • Soils in sun plantations are more exposed to the elements, particularly drenching rains typical of tropical areas.  This leads to erosion of topsoil, and the leaching of chemical fertilizers, pesticides, and herbicides into local watersheds. Soil erosion and acidification and water pollution are serious consequences of growing coffee on sun plantations.
  • Coffee plants in sun plantations grow faster and age more quickly than those grown in shade, and therefore must be replaced more often. Sun-grown coffee trees are typically productive for less than 15 years, while shade-grown coffee trees may yield for 30 years or more.

You can read more about the benefits of growing coffee in the shade in this post.

Donald, P. F. 2004. Biodiversity impacts of some agricultural commodity production systems. Conservation Biology 18:17-37.

Rice, R. A., and J. F. Ward. 1996. Coffee, conservation, and commerce in the Western Hemisphere. Smithsonian Migratory Bird Center and National Resources Defense Council.

Background information / Birds and other biodiversity / Coffee and the environment

Birds and coffee plantations

Traditional, shade-grown coffee plantations harbor a diversity of many taxa — orchids, insects, and mammals, for example.  But it is the research that showed the importance of shade coffee plantations to birds that caught the attention of the public, and really kick-started the shade-grown coffee movement.

Over the last few decades, scientists noticed long-term declines in many species of Neotropical migrants — about 200 species of birds that breed in North America but winter south of the Tropic of Cancer. Researchers were prompted to examine the entire life cycle  of these species.  The ecology of the migrants on their nesting grounds here in North America was fairly well-studied, but more information was needed about the needs of these birds which spend most of their year in-transit or in the tropics. Searching for answers, researchers looked to the wintering areas of “our” breeding birds.

With so much habitat in the New World tropics being cleared for agriculture the importance of coffee plantations to wintering North American migrants (as well as resident species) soon became evident. The multi-layered vegetation of traditional or rustic shade-grown coffee plantations provides food and cover for birds which is in some cases very similar to native forest. In areas where farming has replaced natural habitat with stark pastureland and row crops, coffee farms are sometimes the only quality habitat available.

The Smithsonian Migratory Bird Center’s fact sheet, “Why Migratory Birds are Crazy for Coffee,” notes:

In the regions most heavily used by migratory birds — Mesoamerica, the Caribbean islands, and Colombia– coffee plantation “forests” cover 2.7 million hectares, or almost half of the permanent cropland.

In southern Mexico, coffee plantations cover an area over half the size of all of the major moist tropical forest reserves, providing critical woodland habitat in mid-elevation areas where virtually no large reserves are found.

Under the category “Research on coffee growing,” you can find summaries of some of the research on bird diversity on coffee plantations.  Some facts gleaned from this research include:

  • The majority of bird species in shade coffee plantations are feeding in the shaded overstory, not in the coffee.  The coffee shrubs themselves offer few resources.  This is why sun coffee monocultures do not support a diversity of birds.
  • The value of coffee farms is dependent largely upon the diversity of  their canopy: both the number of different species and the structural complexity of the canopy.
  • Invertebrates, fruit, and nectar are the most important food sources for birds in coffee plantations, so coffee farms are especially important to bird species that feed on these resources.
  • Migratory birds are more flexible in their habitat requirements, and do better in coffee plantations than many resident species, which are more sensitive to habitat changes.
  • Use of coffee plantations by migrant birds is highly seasonal.  Of course, North American migrants are only present in the tropics during spring and fall migration and in winter.  However, even during winter some migrants, in particular those that feed on nectar or fruit, tend to increase in number from early to late winter in plantations where these resources are available.  Three North American migrants are strongly associated with the flowering of Inga trees (which are commonly planted in shade coffee canopy):  Baltimore Oriole (above), Orchard Oriole, and Tennessee Warbler.

Bird diversity in rustic or heavy shade plantations sometimes rivals that of natural forests.  These plantations always have a significantly higher bird diversity (as well as a diversity of other species) than do sun coffee plantations. Shade coffee plantations offer important refuges for species in areas where natural habitats are quickly being converted to agriculture.

It is essential to understand the different degrees of shade under which coffee is grown, because some growing methods even if technically “shade grown,” are not beneficial to birds.

A summary of the eco/bird-friendly, sustainable coffee movement and its associated certifications is within the paper “In pursuit of sustainability: lessons from the coffee sector” by Robert Rice of the Smithsonian Migratory Bird Center.  Annotated PDF here.

Baltimore Oriole photo by Cindy Mead of Woodsong Nature Photography; used with permission.

Certifications

Shade grown coffee certification

As explained in the introductory post on shade grown coffee, there is no set definition of the term “shade grown.”  Coffee may be labeled shade grown even if it is grown under minimal overstory that does little to preserve biodiversity.

The Smithsonian Migratory Bird Center has made the most well-known effort to establish criteria for shade grown coffee.  In order to carry their trademarked “Bird Friendly” label, coffee must be grown under a minimum shade cover of 40%, and the overstory should include at least ten different species of shade trees, with no more than 70% of the trees being Inga species.  Pruning of the overstory and the removal of epiphytes is discouraged, and buffer zones are encouraged. These are the most stringent environmental criteria. Bird-Friendly certification is primarily focused on growers in Central and South America, but expanding to Africa. A description of Smithsonian’s Bird Friendly criteria is here.

The Rainforest Alliance has a certification program (using standards of the Sustainable Agriculture Network) which they apply not only to coffee, but to other crops as well. For coffee, it deals with an array of ecosystem issues such as water conservation, and as well as use of chemicals, community relations, and fair treatment of workers. Certification is awarded based on a score for meeting a minimum number of an array of criteria. More information on Rainforest Alliance standards can be found here.

Unlike Smithsonian’s Bird-Friendly standards, RA has no required criteria for shade management. Therefore it is important to note that Rainforest Alliance-certified coffee may NOT be shade grown. The requirements for shade that are one of the optional criteria under ecosystem conservation can be seen in comparison with Smithsonian’s criteria here. There are seven other criteria relating to ecosystem conservation in the RA standards.

There are pros and cons to the certification process, including the cost to the farmers and roasters (particularly expensive in the case of SMBC), and problems with applying one-size-fits-all biodiversity criteria to different regions. Coffee farmers, particularly small producers, are ultimately in the business of growing coffee to support their families. They are not in the biodiversity preservation business. If we want them to do so, we have to respect that and be willing to make it profitable for them.

Some roasters offer shade coffee that is not certified, but evaluated in various ways. Some say they use independent auditors, or visit the farms themselves.I don’t know how many, if any, of these evaluators have experience in actually assessing biodiversity, from a scientific viewpoint. For more on this topic, please see Who evaluates non-certified coffee?