Domestication of Trees or Forests: Development Pathways for Fruit Tree Production in South-east Asia - Indigenous Fruit Trees in the Tropics: Domestication, Utilization and Commercialization - page 71

to make the most efficient use of the improved tree species. As argued by
Verheij (1991): 'for mixed production systems such as homegardens the
strength lies in stability rather than peak performance. The key to a
breakthrough in productivity of trees, that have been confined in homegardens
because of low productivity in tree crops and hence have been less successful
in migrating to more commercial cropping systems, has always been vegetative
propagation of superior trees.' Gradually, however, this perspective has started
to change as a result of the recognition that the process of domestication does
not only concern adjustment of species to improved quality and yield, but also
to social and environmental concerns (Leakey et al ., 2005). With respect to
such concerns, it was gradually recognized that although monocultural tree
plantations may provide optimal yields in the case of intensive and professional
management, under other conditions they may have several limitations. In
many tropical regions specialized forms of monocrop cultivation do not fit into
the existing farming systems of predominantly smallholder farming. Especially
in the case of less optimal production conditions, farming systems are often
characterized by multifunctional production, which focuses on a range of
subsistence and commercial products. Such technically non-optimal
management may be related to the fact that the tree cultivator lacks the means
to obtain all the necessary external inputs needed for intensive tree cultivation.
Under such conditions, mixed production systems are often more relevant than
highly specialized monocropping systems. Moreover, in case of non-optimal
management, monocultural plantations may be subject to ecological hazards
such as fluctuating weather conditions or attacks by pests and diseases. Multi-
species systems make it possible to make use of synergistic ecological
processes, such as: (i) circulation of nutrients as the result of the presence of
filters against loss of nutrients; (ii) plant protection as a result of the presence of
buffers against damaging agents such as pests and diseases; and (iii) protection
by vegetative barriers against potentially degrading forces such as torrential
rainfall, surface runoff or strong winds (Schroth et al ., 2004a).
As a consequence of the multiple dimensions of the domestication process
and the range of social concerns related to production systems, several
important questions have to be addressed in research on fruit tree
domestication. First, attention should be given to the type of production system
used to grow the tree (Leakey et al ., 1996) and what, sometimes multipurpose,
role the tree is expected to fulfil in this system (Chuntanaparb and MacDicken,
1991; Roshetko and Evans, 1999). Secondly, attention needs to be given to
how fruit tree production can best fit into the overall farming conditions of
specific groups of cultivators. In view of the fact that fruit production systems
are often specifically promoted as a contribution to poverty alleviation under
marginal production conditions (Leakey et al ., 2005), the specific production
requirements of smallholder producers must be considered (Raintree, 1991;
Warner, 1995). And thirdly, attention needs to be given to the question of how
the fruit tree cultivation system can best meet present environmental and
ecological concerns (Schroth et al ., 2004a). In order to assess such questions
under location-specific conditions, it is essential to have a good understanding
of the process of change from the wild to domesticated state. Against this