Fire has always been apparent to some extent in humid tropical forest as an agent of disturbance leading to forest renewal through succession and even to long-term changes in the biome (Flenley, 1979; 1992; 1998). Under climatic conditions of occasional drought there is an element of natural forest fires occurring without human interference (Goldammer, 1992) although this is difficult to establish because the use of fire also links back to the earliest forms of agriculture (Boserup, 1965; Steensberg, 1993). Today however, the role of man is more evident than ever before in understanding the dynamics of fire, humans and vegetation ecology (Uhl, 1998).
Perceptions by lowlanders of a loss of ‘forest catchment functions’ due to ‘upland shifting cultivators’ are often strong but these may not be based on a clear understanding of the cause-effect chains involved. For example, most major and capital cities in South East Asia have been built on floodplains at the mouths of rivers, i.e. in areas where occasional flooding is to be expected regardless of the forest cover of the uplands (Hamilton and King, 1983). When floods do occur, however, land use change in the uplands provides an easy scapegoat, especially if the uplanders have a different ethnic and cultural background, as for example in Northern Thailand. These conflicts over land use change in the uplands have reached such an intensity in some areas that basic research findings are not likely to modify the perceptions and standpoints of different stakeholders in the conflict (Van Noordwijk, pers. obs.).