Changes in Melaleuca forest density on the Magela floodplain, Northern Territory, between 1950 and 1975

The stability of the Magela floodplain prior to the development of uranium mining at Ranger, in the Magela catchment, was estimated by comparing aerial photographs taken in 1950 and 1975, using the density of Melaleuca swamp forest as an index of change. The 1975 photographs were interpreted in the light of a ground survey carried out in the dry season of 1976. There was no increase in the area occupied by Melaleuca trees, indicating that infilling of perennial swamp and plant succession were not significant agents of change in this period. Thirty‐eight per cent of the forested area suffered a significant decrease in tree density: fire, wind and buffalo are among the probable causes, and these hazards should be taken into account in monitoring the effects of the uranium mining.