Human impacts on tropical forest dynamics

Abstract

People living near or in tropical forest ecosystems have traditionally extracted forest products, i.e. timber, food and medicinal plants for their livelihood. Such practice does not create too much disturbance when the population is still sparse, and the product is used only for their own needs. When population pressure becomes greater, and when the motive of extraction is profit, then the disturbance become serious and created environmental problems. Major exploitation of the Indonesian rain forest for timber began in the 1960s and is continuing today. The lowland rain forests of Sumatra and Kalimantan have been particularly logged. Exploitation has often been destructive because Forest Department rules have been widely ignored. Moreover, once roads have given access to formerly inaccessible areas, farmers have often moved in after the timber companies and then cleared the relict, regenerating forest for either permanent or shifting cultivation. The traditional shifting cultivations have been practised for years, producing millions of ha of impoverished secondary types of forest, degraded lands and alang-alang (Imperata cylindrica) grasslands. Forests have also been lost through conversion of land to plantation agriculture and transmigration programmes, mining, construction roads and railways and also natural disturbances, such as drought and fire. This paper will discuss the human impact upon tropical forest dynamics in general, with examples from Indonesian and other Southeast Asia countries' tropical forests.