Some countries in South-East Asia such as Vietnam and the Philippines embark on ambitious programmes for regreening degraded land by planting trees. As with reforestation schemes for the pulp and paper industry in Malaysia and Indonesia, these new forests are largely stocked with tree species exotic to the respective area, mainly Acacia spp. and Eucalyptus spp. Rationales for this preference are well-known. Easy storage of seeds and mass propagation, and higher survival rates of seedlings in open areas in comparison with many native quality timber trees, in South-East Asia above all dipterocarps, are rather uncontested points. Other arguments, for example, faster growth or higher resistance to pest and diseases of exotic trees compared with native quality timber trees do not bear up to critical examination in all cases. However, beyond these silvicultural aspects there are other issues in the debate on exotic vs. native tree species which deserve a closer look.