The project was designed in conjunction with Man and the Biosphere (MAB) Programme Project No. 1 to provide scientific data on the effects of tropical forest clearance with a view to future long-term management of kerangas and mixed dipterocarp forest. Control plots from both forest types were described in detail together with secondary forest established for 35 years. Experimentally treated plots were clear-cut and burnt and the changes in soil and vegetation followed and described in detail for 1.5 years. The two initial forest types represented a range of forest formations in the tropics from poor to rich conditions. Fluctuations in the control plots were followed for 1 year. The whole process of recovery was different in the two forests: in the strategy of individual there species, the species composition and changes in soil nutrients. A variety of conclusions about the trees, saplings, seedlings, shrubs and herbs components, turn-over periods, biomass, natural regeneration and species composition of these forests are dealt with and further conclusions out with the scope of this thesis will be published later.