Introduction
Over the last few years, there has been increasing interest in agroforestry.
Agricultural systems of these types have the potential to reduce land
degradation due to poor or intensive farming practices, while increasing
agricultural production, farm income, and reducing risk. Many nations in
the world face problems of rapidly increasing populations, a scarce or
declining arable land base, and the need for environmentally compatible
agricultural systems. To deal with these problems, ecologically sound
systems, such as intercropping, agroforestry, and multi-species plantation
forestry are gaining increasing attention in forestry and agricultural
development planning and practice.
Historical reviews have shown that complex multi-species agroforestry
systems are viable [Fernandes et al., 1984; Michon et al., 1983; Wiersum,
1982; Denevan et al., 1985]. Research has shown these systems to have
ecological advantages [Altieri and Liebman, 1986; Jordan, 1985] and can
potentially offer some economic advantages [Hoekstra, 1987]. Despite the
promise of agroforestry, there is a lack of good data on production and
economic viability of various agroforestry systems. One reason for this is the
complexity of mixed species systems. Researchers must deal with an exponentially
greater number of variables with multi-species systems than with
monocultural systems [Barker and Francis, 1986]. For mixed species agriculture
to gain widespread acceptance, more information on productivity and
economic viability are needed.