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Fifteen years ago, approximately half the world population was estimated to live in continental and insular South-East Asia (Burma, Thailand, Kampuchea, Vietnam, Laos, Indonesia, Philippines). Then the region had a population growth of four million people every month, and the problem of malnutrition was acute for the rural population. International agricultural development organisations decided that their primary aim would be to double existing levels of agricultural production and, taking account of population growth, to double it again by the end of the century (Whyte 1976). Today, while global issues have greatly affected the parameters of the problem, the situation remains both serious and difficult. Despite impressive efforts in education and health, Indonesia for example, where population (179 millions) growth eased off only slightly between 1980 and 1990 (from 2. 3 percent to 1. 9 percent), is having to cope with increasing difficulties in managing natural resources and particularly its evanescent forest assets which, until 1986, were the second largest source of national revenue. Indonesia has the second largest surface area of tropical rain forests in the world (after Brazil) and thus all the problems linked with management and disappearance of those forests. The latest estimate gives a figure of 109 million hectares of forest in 1990, of which 40. 8 million hectares are production forests (Anon. -F AO 1990).
Sommario
1. Methodology.- Critical review of the main methods used for vegetation mapping and vegetation studies in the tropics.- Method used for vegetation classification and analysis during the present survey.- 2. Physical environment and physiographic classification of the vegetation.- Geomorphology, geology and pedology.- Bioclimates.- Rainfall patterns in Sumatra.- Physiographic classification of the vegetation.- 3. History of the vegetation and phytogeography.- History of the vegetation.- Phytogeography of Malesia.- Phytogeography of Sumatra.- 4. Vegetation and forest types.- A short cartographical analysis of the main plant formations of Sumatra.- Plant formations in lowland swamp areas (alt. < 15 m).- Plant formations of the plains and piedmonts (drained soils at low elevation, 2500 m).- Agroforestry formations.- 5. Conclusions and perspectives.- 6. References.- 7. Species index.- 8. Appendix I. List of available maps used for the present study..- II. Legend and planimetry of the vegetation maps..- III.Ecological vegetation maps.(Color Plates).
