Tree–Crop Interactions in Fruit Tree-based Agroforestry.pdf

Chapter 8 Tree–Crop Interactions in Fruit Tree-based Agroforestry Systems in the Western Highlands of Guatemala: Component Yields and System Performance 1, 2 2 J.G. Bellow *, P.K.R. Nair , and T.A. Martin Introduction Trees grown on farms for their non-timber forest products such as fruits, nuts, and spices constitute the basis for many vibrant and sustainable farming systems through- out the world. Yet, compared to other types of trees, research on horticultural and agronomic management of such trees and systems to optimize total system-yield and understand tree–crop interactions is scarce. Farmers prefer fruit-producing species to other trees for on-farm planting (Raintree, 1992; Franzel et al. 1996), and appre- ciate the dual contributions of food for consumption (Salam et al. 2000) and the potential for income generation (Delobel et al. 1991; Ayuk et al. 1999). Fruit trees are considered advantageous because of the relatively high returns to labor resulting from low labor inputs (compared with annual crops); moreover, fruit tree-based systems also offer a more uniform distribution of income throughout the year than annual crop systems. However, the relatively “free” availability of forest-based timber- and fuel wood products in some areas are seen as disincentives for growing tree species for those purposes (Hellin et al. 1999). In temperate regions, the dependence on mechanization (Herzog, 1998) and policies that discourage long-term endeavors (Mary et al. 1999) have limited the extent of fruit-based agroforestry. In tropical and subtropical regions, more often the difficulties are in marketing. Generally, fruit-based systems are economically rewarding with high benefit-to-cost ratios and total system-productivity in fruit tree + annual mixed systems remaining high although individual yields of annu