Factors That Determine the Use of Shade in Coffee Plantations
This historical analysis indicates that the observed variations in shade design
and management of coffee plantations worldwide result from combinations of
three major factors:
- Local climate and extreme environmental conditions that limit coffee yields:
Shading is needed in dry and hot areas, windy places (e.g., Croton reflexi-
folius windbreaks in El Salvador; Escalante 2000), frost-prone areas
(Caramori et al. 1996; Baggio et al. 1997), and sites affected by acid rain
from nearby volcanoes (Bonilla 1999). The use of shade is unnecessary in
cool, humid, and cloudy highlands. For instance, little shade is used in cof-
fee-growing areas of Costa Rica at more than 1,200 m altitude and
2,500–3,500 mm year–1of rainfall (E. Somarriba, pers. obs., 2002). - The compromise between expected coffee yields and plantation longevity:High
coffee yields can be attained in lightly shaded or open sun coffee plantations
and with intensive use of agrochemicals. However, plantation longevity is
reduced, and the whole plantation must be renovated more frequently (e.g.,
every 12–15 years in open sun plantations compared with 15–20 years in
shaded plantations). Plantation renovation is an expensive task, and the
farmer must face 2–4 years without coffee production while coffee plants are
still young. The use of shade increases plantation longevity and reduces the
need for expensive agrochemicals at the expense of lower coffee yields. Each
farmer chooses a place along the continuum between these two extremes. - Plantation size and the need for production diversification:Big and wealthy
farms that specialize in coffee production use very simple shade canopies
with one service shade species (such as Ingaor Erythrinaspp.) that is
planted, pollarded, and thinned according to the needs of the coffee plants.
In contrast, small coffee farmers commonly opt for a diversified, polycul-
tural system with a diverse shade canopy including several species of fruit,
timber, firewood, and other types for home consumption or sale. In these
polycultural systems shade cannot be regulated to satisfy the needs of only
the coffee plants (e.g., pruning fruit trees to enhance fruit production may
not be the best way to regulate shade for the coffee beneath), and this may
reduce coffee yields.
Structural Types of Coffee Plantations
Structurally, coffee plantations vary along a continuum from very simple to
very complex (Figure 9.1). Schematically, the following structural types can be
distinguished:
•Open sun monocultures (with no shade canopy).
202 III. The Biodiversity of Agroforestry Systems