Abstract: Based on the multi-temporal Landsat TM images in 1988, 1998, 2003 and 2006, and by using neighborhood analysis, the top 5% areas with the quickest change rate of settlement percentage coverage in Nanjing in 3 periods of time in 1988〖KG-*2〗-〖KG-*7〗2006 were picked up as the hotspots, aimed to study the settlement dynamics in the urbanization process of the City. The results showed that with urban expansion, both the growth hotspots and the shrinking hotspots in Nanjing exhibited an overall outward-shifting tendency. The growth hotspots mostly located in the regions 6 km from the fringe of urban built-up areas, while the high-occurrence zone of shrinking hotspots was located in the regions 1 km from the fringe of the built-up areas. Moreover, the areas of the two kinds of hotspots declined with the distance along the urban-rural gradient. The intensity and range of the hotspots varied significantly among different directions, and tended to be influenced by the short-term urban development decisions. At some specific stages, the primary urban development zones generally presented in growth hotspots, which resulted in the temporal variation of hotspot-concentrated locations. The shrinking hotspots were concentrated in the areas experienced growth hotspots in previous periods, indicating that relatively extensive settlement reform and integration could occur after the rapid settlement growth in urbanization process.

Key words: Poplar, Water stress, Nitric oxide, Oxidation damage, Protection