uth-East Asia.
This is still more true of economies with minimal involvement in agriculture, and reliance principally on wild or semi-sown food sources, and on the hunting and fishing of wildlife. A low population density is an essential part of the environment of such a system. The whole problem will therefore be illustrated here with reference to the situation observed among one of the now more famous tribal communities in South-East Asia-the Penan of Sarawak, who, as claimed in much recent writing (for example, Hong, 1987; INSAN, 1989; Sahabat Alam Malaysia, 1990), are still practicing an economic system which is ecologically in balance with the environment. It is proposed, especially by many environmentalists, that the best way to ensure a sustainable future for the Penan is to maintain their traditional way of life as a nomadic tribe.
The penan and the timber blockade
The Penan have attracted global attention since 1987 through their blockade of timber roads. In general, however, outsiders' perceptions of the Penan tend to differ from the actual situation. Despite all the changes that have occurred, most current descriptions of the Penan still tend to follow the ethnographic models: an isolated society hitherto unaffected by or not interested in interacting with the outside world; self-sufficient and contented with their traditional way of life even to the extent that they are not interested in any worldly possessions from the outside. While these notions may fit some pre-1960 Penan communities, it is no longer the case in over 90 per cent of the current Penan societies concerned. There is no doubt, of course, that the Penan everywhere in Borneo are economically the most backward.
In 1987, the Penan embarked on large-scale blockade of timber roads in the Baram district of Sarawak, one of the main logging areas in the state. A number of reasons have been put forward to explain the blockade. Prominent among these is the destabilization of the traditional economic systems of the Penan, principally the destruction of their food resources as a result of the timber industry. Some research tends to support this contention. In Sarawak, one group of studies which specifically focused on the impact of logging on wildlife found a significant reduction in the number and diversity of resident species and a decline in meat harvest from logged areas (Bennett, 1982; Caldecott, 1986; Caldecott and Nyaoi, 1985). But the Penan do not hunt all types of wildlife for food, and the studies did not examine the impact on those types of wildlife important to them as food resources.
The timber industry was also blamed for the depletion of the most important food resource-upland sago palm, the Penan's traditional staple. Here again, much of the argument was based on assumptions. Does logging destroy the traditional food resources of the Penan? While logging is a factor, the impact is largely indirect. The damage to the sago clumps resulted mainly from the exploitation of the sago shoots by local timber workers for whom they are a delicacy. Ongoing research by the author suggests that the damage caused by the felling of trees is minimal, for the main reason that most of the sago clumps are found in terrain which is difficult to log.
The depletion of sago and other jungle resources is not confined to areas affected by the logging industry. It also occurs in areas inhabited by semi-settled and settled Penan and which are not affected by logging. In fact, the situation is very serious in areas where the Penan have changed to a settled life. The communities in the Tinjar region, for instance, have experienced a shortage of wild sago since the mid-1960s, long before the emergence of the timber industry. Indeed, this scarcity was a main factor behind their decision to settle and cultivate, a factor which is also observed among Penan groups elsewhere.
The depletion of this traditional natural source of food supply is to a large extent caused by changes taking place within the society rather than being the direct consequence of external interference. T