 in studying the environmental future of threatened people, especially the indigenous tribal people of South-East Asia. Are they capable of devising measures to shield their culture from being overwhelmed completely by outside influences? What are their limitations? These are stimulating questions for research. Contrary to popular opinion, tribal people, and probably almost all groups of threatened people, are not completely at the mercy of the advanced socio-economic groups, although there are limits to their ability to counter external influences which could destabilize their culture. The rest of this chapter examines this complex and sometimes controversial subject, and is based largely on the situation observed among some tribal groups in Sarawak.
The Orang Ulu Tribes of Sarawak
The Orang Ulu' of Sarawak, consisting of approximately two dozen distinct tribal groups, are among the smallest of the indigenous tribes found in Sarawak. Their small population size, as well as the fact that these communities were frequently in conflict with each other in the past, made them very vulnerable socio-economically and otherwise. Among the important features of their cultural history have been their constant movements from one river valley to another, both for security reasons and to establish control over jungles rich in important forest products (Lien, 1987; Southwell, 1959). Imported goods obtained from the exchange of jungle products played a very important role in the socio-cultural and economic systems of the Orang Ulu, and this has been true for centuries.
In view of the central importance of land in their livelihood, and acknowledging their weaknesses in any direct form of political conflict and confrontation with the early colonial Brooke regime, the Orang Ulu were compelled to compromise, and to surrender to the regime their past claims of political 'sovereignty' over territories which they occupied, in exchange for the security of rights over land and resources (Lien, 1987). They took advantage of the peaceful political atmosphere created by non-invasive colonialism under the Brookes between the mid-nineteenth century and 1941, to enhance their social and economic standards by migrating to new areas which were abundant in jungle resources, and which were also relatively more accessible to traders. Thus, the cession of the Baram River valley to the Brooke government by the Sultan of Brunei in I 882 was followed by constant migration of Orang Ulu communities into the Baram. The Baram River valley is more easily accessible by boats, far into its upper course, than is the upper Rejang River valley, the traditional homeland of most Orang Ulu. Some others moved from the remote volcanic plateau of the Usun Apau, close to the modem border with Kalimantan, into the river valleys of the Baram system.
None the less, the downriver migration of the Orang Ulu did not, until after the midtwentieth century, extend beyond the lower limits of dry undulating land. Lian (1987) relates this limitation to two main factors. First, it was to prevent cultural over-exposure to outside influence. Secondly, and more importantly, it was because of the lack of land suitable for practicing shifting cultivation beyond this topographic limit. Both factors have moulded the Kenyah, the Orang Ulu group to which the author belongs, to remain relatively cohesive until even today while maintaining their economic relationship with the outside world.
Today, the migration pattern is increasingly towards places where wage-employment opportunities are found, that is, principally in the rural areas, rather than being mostly rural-urban in nature. The Orang Ulu continue to abandon selected aspects of their culture and traditions-some of which had been important in serving their needs, especially their subsistence needs-in order to accommodate certain elements of the new socio-economic systems into their culture, while preventing the erosion of its more basic and fundamental aspects. For example, communal forms of production which had been an important economic stra