The concept of sustainability emphasizes four basic principles when applied to rural communities: that basic needs must be met; that resources should be subject to local control; that local communities must have a decisive voice in planning; and that they should represent themselves through their own institutions. These principles have been notionally accepted by development planners and conservationists at all levels. Yet, throughout the tropical forest belt, they are being systematically overridden by international and national policies and development programmes, leading to increasing poverty, social conflict and rapid deforestation. Traditional knowledge and systems of land use have proved far more environmentally appropriate, resilient and complex than initially supposed by outsiders. Forest peoples have successfully opposed many socially and environmentally destructive development schemes proposed for their lands. However, these societies are not resisting all change: population increase and the internal dynamic for development have also created social and environmental problems. A review of community-based initiatives in South and South-East Asia shows that in some countries, positive initiatives have been taken by local and national governments to promote a community-based approach. Notable successes have been achieved but many other initiatives have failed. The examples show that, besides the four principles noted above, environmentally successful management also depends on innovative political organization at the community level.