several decades and tolerance of spontaneous forest regrowth, these systems
gradually evolve into a type of managed secondary forest enriched with rub-
ber trees, the so-called jungle rubber (Gouyon et al. 1993; de Jong 2001).
Similar systems have been described from the central Amazon (Figure I.2;
Schroth et al. 2003).
Highly complex systems also arise from practices found in southeast Asia
and some parts of the Amazon, where farmers plant a food crop (e.g., upland
rice) and intercrop it with one or two timber or fruit tree species that have a
tall canopy. After harvesting the crop, they plant other timber and fruit tree
species with intermediate-level canopies, to be followed by other tree species
with lower canopies, creating systems that have an appearance almost similar
to that of a natural forest. These systems, which include the damar (Shorea
robusta) and durian (Durio zibethinus) gardens of Sumatra, have appropriately
been called agroforests (Figure I.3; Michon and de Foresta 1999). In parts of
Latin America and West Africa, coffee and cocoa (both shade-tolerant crops)
traditionally are established under an open canopy of remnant trees that were
retained when a forest plot was cleared (Johns 1999; de Rouw 1987), result-
ing in another type of complex agroforest. Similar tea-based systems have been
described from northern Thailand and Myanmar (Preechapanya et al. in
press).
Throughout the tropics, smallholders commonly plant trees in small
homegardens for shade and various products such as fruits and medicinal
products (Figure I.4; Torquebiau 1992; Coomes and Burt 1997). They may
4 Introduction: Agroforestry in Biodiversity Conservation in Tropical Landscapes
Figure I.1. Parklike landscape with scattered trees in pastures and crop fields in the
northern Côte d’Ivoire, West Africa.