An analysis of human impact on humid, tropical forests in Jambi, Indonesia using satellite images

Humid tropical forests cover over 3 million hectares of the Earth´s land surface and they are regarded as one of the major biomes in the world. There is increasing awareness of the impacts of the loss of humid tropical forests on global biodiversity and climate. This paper focuses on a 120 by 120 km stretch of the swamp forest area on the eastern coast of central Sumatra, Indonesia. It aims to document and trace the history of resource use of the peat swamp and lowland forest areas, by analyzing and comparing the dynamics of the conversion of these areas into plantations or agricultural plots for the past 15 years. The fires involved in clearing the land for agriculture and plantations account for much of the damage to the forest environment. This has grave consequences since both types of forests, especially peat swamp forests, play an important ecological role in the stability of the global climate and maintaining biodiversity. Two land cover maps of the same area were obtained by classifying SPOT images from 1999 and Landsat TM image from 1989, using a 1986 vegetation map of Sumatra as a guide. The 1986 map was also digitized to obtain a baseline for comparison. By comparing images and maps from these years, an estimate of the extent of old and new land uses of peat swamps and lowland forests over the past years was obtained. The extent of the damage from the fire episodes of 1997 and 1998 in the area was also estimated. Most of the burnt areas occurred in the swamp forests. Land use change in the swamp area is increasing rapidly