cial and economic needs, objectives and aspirations. Indeed, the industry has enabled some to leap out of the agricultural into the non-agricultural sector. But, as in the past, the Orang Ulu planned their involvement in the timber industry in ways which would least disrupt important aspects of their traditional life, in particular the shifting-cultivation production of rice which is regarded as their basic 'survival kit'. Since wage employment is in direct competition with cash-crop cultivation, the consequent decline in their agricultural cash-crop economy is therefore to be expected.
Participation in the timber industry has also indirectly resulted in the degradation of their swidden land because the shortage of male labour for swidden led to the intensification of the use of fallow land close to the long-houses. But the Orang Ulu see this as a temporary problem, and of less pressing nature compared to the benefits gained from engaging in a timber industry which, as has clearly been understood, will be operating only temporarily.
This response to innovation clearly demonstrates that the penetration and introduction of outside systems can be used to strengthen tribal cultures. Many South-East Asian tribes are capable of accommodating and even insulating their cultures from excessive outside influence. In the Philippines, Keesing (1962) noted how the lowland Filipinos frequently escaped Spanish repression by moving to the mountains. This response is still used. Internal colonialization from both national and international sources has continued to push or force small tribal groups into marginal areas (Atal and Bennagen, 1983; Eder, 1987). Others have used more subtle means. In his brilliantly written book, Weapons of the Weak, Scott (1985) described how the small-scale paddy farmers in Kedah, in one of the main paddy-cultivation areas of Malaysia, succeeded in expressing their grievances and opposition to certain government development policies by using the 'foot-dragging' method of silent protest. The same is also true of many other tribal groups.
The indigenous socio-economic system: Is it sustainable?
While asserting the ability of many threatened peoples to adapt, and stressing the resilience of their traditional economic systems in handling many external influences, it still has to be asked whether the traditional system by itself can, in the light of continued pressure from outside as well as from within the society, provide tribal groups with a sustainable future. While indigenous skills could be an appropriate starting point for trying to improve technologies suitable for tribal societies, there is also evidence which suggests that not all indigenous resource-use practices are ecologically and environmentally sound. Increased population pressure on land resources, increased dependency on a commercial economy, and demand for cash incomes have brought about environmentally destructive changes in native resource-use patterns.
This is most evident in one of the principal traditional agricultural systems- swidden agriculture, which is frequently portrayed in modern environmental literature as ecologically sound. While it was indeed so in the past, all evidence in South-East Asia suggests that population density is a key variable in the sustainability of the swidden system (Cramb, 1978; Dove, 1981; Spencer, 1966). The maintenance of an adequate long fallow period-the critical basis for sustainability-depends on a sufficiently low man-land ratio. But in South-East Asia, even in the sparsely populated island of Borneo, there are only a few regions, especially agriculturally suitable areas, where such a situation still prevails. In other words, the assumption of socio-economic and environmental equilibrium in tribal societies is gradually becoming a misplaced notion. Economically, this is partly exemplified by changing land-use patterns, especially the pattern of a mixture of subsistence and commercial agriculture in place of swidden, which by the early 1990s characterizes the rural cultural landscape of large parts of So