熱帯地域における焼畑研究の展開

生態的側面と歴史的文脈の接合を求めて

抄録

This paper aims to clarify current trends and issues in studies of swidden agriculture (shifting cultivation) and its societies in the tropics. These studies are characterized by multidisciplinarity and a close relation to global issues concerning environmental and ethnic problems. In order to solve these overriding problems, it is suggested that diverse interests are rearranged among these studies and that they be integrated into the context of problem-solving from a pragmatist standpoint. Keeping such a viewpoint in mind, I have attempted to reexamine relevant case studies from these three contexts: (1) relationships between agricultural technology and regional environment (2) diachronic aspects of shifting cultivation and problems of reconstructing environmental history (3) socio-economic change in local societies accompanying the globalization of politico-economic systems. The results are summarized as follows.
(1) A typical argument on the relationship between the physical environment and swidden technology was that of Geertz (1963), who argued that swidden cultivation 'simulates' tropical forest ecosystems. Many field studies have been carried out to examine the appropriateness of his argument (Rappaport 1971), and some have clarified the regional diversity of swidden systems and technologies which have a close relation to the diversity of regional environments (Hames 1983; Vickers 1983).
Technological diversity can be primarily understood as an adaptation to the diversity of the physical environment. It can be best explained by the contrast between the humid tropics and savanna environments. For instance, 'slash/mulch systems' of swidden agriculture observed in the humid tropics can be said to be the technology which has adapted to the uncertainty of the seasonal rainfall pattern (Sato 1995; Thurston 1997). In contrast, citemene systems, which prevail in the Zambian savanna, is the technology which makes full use of the 'burning effect', making up for infertile savanna soils (Araki 1998). Various types of cyclic 'field and fallow' systems are the result of such technological selections in indigenous societies.
Not only the physical environment, however, but also other multiple factors influence technological selection. One of the most important is the relationship between population and productivity. Among the arguments related to this problem, noteworthy is the fact that, historically, state power has affected the intensification of swidden societies, rather than the popularly accepted view of attributing it to internal population pressure (Dove 1983).
(2) There still exists a deep-rooted tradition of an illogical jump to connect indigenous shifting cultivation with global environmental degradation, such as deforestation. While there are not enough empirical data to show diachronic relationships between shifting cultivation and global environmental change, several case studies prove that indigenous cultivators have played a positive role in keeping and promoting community forests for subsistence purposes (Fairhead and Leach 1996).
We should note, on the other hand, that there are ambiguous and complicated factors in the meaning of fallow and resettlement of the swidden cycle. In the context of long-term environmental change, we should give careful consideration to the combinational aspects between the long-term 'resettlement cycle' and short-term fallow systems. The long-term aspect has not been seriously questioned because of a lack of verification sources, but recent technological developments in remote sensing will improve the situation. Such a direction, anyway, must be combined with empirical data through intensive observations, so as not to misinterpret the implications of phenomenal change in the tropical environment.
(3) Since there is no local society which has never come into contact with a state government and the global economy,