ENVIRONMENTAL CHANGES IN RELATION TO TREE DEATH ALONG THE KUISEB RIVER IN THE NAMIB DESERT

Abstract

The Namib Desert is located along the western coast of Namibia and is affected by the cold Benguela Current. Although forest is distributed along the Kuiseb River in the Namib Desert, many trees are almost dead in some areas. The aim of this research was to clarify the relationship between environmental changes and tree death. The results of the survey are summarized as follows: (1) Many dead trees are located on the riverbanks made of dune sand, which are about 1 m high. (2) Dead trees are located in transitional areas where a northward protrusion of the southern shore is followed by a southward protrusion of the northern shore along the course of the river, in proximity to a sand dune. (3) Floods have eroded the noses of advancing sand dunes of the upper stream and have caused tree death by depositing sand. (4) The date of tree death has been estimated between the late 1970s and the early 1980s by 14 C dating. (5) Flood days numbered 33 per year from 1962 to 1975 and 2.7 from 1976 to 1985. The remaining thick sand layer, deposited by the last fl ood, may be the cause of tree death, given that there was drastic decrease in fl oods since 1976. (6) Tree death has greatly affected people's lives along the Kuiseb River because they depend on riverside forests as a source of shade, shelter, fuel, and food for humans and livestock.