Study On Landscape Structure Of Woodland In Nanjing

The urban green space system is in a pivotal role in urban construction planning.As an important part of urban green space system, the changes of woodland's pattern have a profound impact on the urban landscape architecture and urban ecological environment, economy and culture of the cities. By analyzing the structure of the urban forest landscape status and evolution of the trends, the city can be drawn if the woodland landscape layout is reasonable, if it can give full play to their ecological and social benefits, thus it can provide science basis for building a rational structure, scientific distribution, functional and efficient system of urban green space. Therefore, analysis of the process of urbanization in urban woodland pattern of Nanjing and the impact of the mechanism for rational planning urban green space system, has an important guiding significance in planning urban green space system and guiding the development of urban green space for rational.This paper used 1988,1998 and 2006 three different periods of the TM images of Nanjing as the main source of information,used GIS software and landscape pattern analysis software FRAGSTARTS,studied the evolution of the three different time of landscape pattern. Analysis would be divided into four parts: In the first part, it took the changes of the Nanjing woodland landscape pattern in the overall analysis, the main choice for quantitative analysis to compare three different sessions was the index of landscape pattern of Nanjing woodland landscape changes. The second part, it analyzed the changes of the gradient of urban and rural areas into woodland landscape pattern. Through the gradient analysis, it studied the woodland features of different level of urbanization on areas and the visual impact of urbanization on the woodland landscape pattern. The third part, it took the woodland landscape pattern of different administrative districts in Nanjing for temporal and spatial variation analysis. This article mainly used the transfer matrix method, focused on the status and the changes of woodland in relatively new and the old town. The impact of the pace of progress of urbanization and development of ways on the change of the woodland landscape pattern was analyzed in the part. Part four; it analyzed the impact of urban road construction on the woodland landscape pattern by using the buffer zone analysis method. The results show that:1. From 1988 to 2006, hard ground of Nanjing City area continued to increase, the total forest area at first decrease and then increase; The rate of low vegetation coverage was increasing and the rate of high vegetation coverage was declining; The degree of fragmentation of woodland was easing, but because of the increase in the number of small patches, the proportion of them was large, the shape of them was complex, they had poor stability. According to the survey, from 1988 to 1998, there was serious damage on woodland. However, due to the urbanization was in the early stages, most of the woodland changed into farmland, wasteland and so on, rather than directly into urban construction sites. From 98 to 06, the increase of woodland area was mainly due to the recovery on the woodland of previous destruction, and vigorously artificial afforestation results.2. The performance of the changes of woodland landscape on the gradient area from urban to rural show: in the different geographical areas away from the city centre, the degrees of interference on woodland landscape are different. The change in the first ring near the center was modest, and it had the minimum percentage of woodland, the lowest density of patches and the simplest shape of patches, the degree of fragmentation was increasing year by year. With the increase of distance from the city centre, the extent of the changes of woodland landscape pattern increased, it was the largest in the transitional zone, and the destruction of the woodland was also the most serious.3. From the comparison of woodland landscape pattern in the new and old town, in the old town, the area of hard ground was increasing but the woodland was decreasing. In the new town, the area of hard ground and woodland were both increasing. The extent of change in the old town was smaller than the new town; in the old town, the patches of woodland are relatively small and more scattered, they had a high density but their stability was not high, the degree of fragmentation was relatively high, the heterogeneity was large. But in the new town, there were a great number of large and medium-sized woodland patches, the degree of fragmentation was lower compared to the old town.4. There was a great impact on the woodland landscape pattern by road construction. The road occupied part of woodland, and other urban construction caused by the road construction also had destruction on woodland, the degree of fragmentation was increasing. In addition, because of the different period of the road construction, different geographical location and so on, the impact on woodland landscape pattern was also varied. The woodland had been serious damaged in those areas of rapid economic development and high urbanization.At last, according to the results, we try to make the following recommendations: Do a good job in Nanjing woodland conservation, restoration and construction work, especially the protection and restoration work of the large-scale woodland, to increase the total urban area of woodland; promoting the construction of woodland in any possible areas in the old town. At the beginning of the new urban planning, set aside some woodland in advance, build a reasonable and efficient urban forest by correctly collocating of trees, shrubs and herb to change the green model of low-density; Construct a reasonable, effective and ecological road network, do a good job of conservation and management work on both sides of the road in the early construction of the road, reduce the damage of woodland by road construction as much as possible and eventually build a harmonious urban ecosystem.