Local Urban Forest Structure And Ecology Study

Based on the present situation of urban forests in and abroad, the concept of urban forests was discussed comparing the other related concepts, the experience and the problems in the urban forests development were also analyzed. By the method of RS, GIS and the field survey, the structure of the small area urban forests was analyzed qualitatively and quantitatively. Ecology benefit of the 2233 trees in the study area was calculated used CITYgreen model. It was very useful for the urban forests construction and maintenance.Using the results and the experience of the urban forests research in and abroad for reference, combined with the urban forestry research in China, we discussed the concept of the urban forests deeply according to the theory of the ecology. It was not a long time for the course of the urban forests development in China. A lot of attempts were carried out. And many problems were turned out. The imbalance development and the non-systemic research should be settled for the future healthy development.Basing on the field survey and indoor work, we established the database for this research, using the aerial image as the data source, the ARCVIEW and the CITYgreen as the software platform, including spatial data and attribute data.The results of the horizontal structure in the study area: there were totally 39 species in the study area, belonging to 25 categories and 28 families; the amount distribution was uneven, five main species has the majority amount, adding up to 1482, the total amount of 66.37%; the species diversity varied greatly in different streets in study area, it was different between the street and the integer; the trees were distributed as"dispersed spots-street line-local area-interlaced net", taking the streets as the framework, looking as the closed net.The results of the vertical structure in the study area: the ratio of the three grades in height was 7:6:4, most of the trees were in the two grads above 0.25m; the amount structure in diameter at breast height was reasonable, as normal distribution. The ratio of the three grades in diameter at breast height was 10:33:27, most of the trees were in the range of 0.25m to 0.5m; the coverage ratio in the study area was 33.31%, in which 50% was the community type 3, arbor-paved structure, it was the low-level ecological function, which covered the 16.84% of the total area; the general healthy state in the study area was all right, which was different among different trees.Using the CITYgreen model, we calculated the general ecology benefit at present and in future. The general ecology benefit in both carbon-settlement and air pollutant-cleanup in the year 2006 was 1300293.04 yuan, the general ecology benefit in the year 2016 will be 2403204.5 yuan, the general ecology benefit in the year 2026 will be 2660498.83 yuan, the general ecology benefit in the year 2036 will be 2873597.93 yuan, the general ecology benefit in the year 2046 will be 3013583.22 yuan, the general ecology benefit in the year 2056 will be 3077677.47 yuan.Using the CITYgreen model, we calculated the ecology benefit of the five main species at present and in future. Taking Platanus hispanica for example, the ecology benefit of the Platanus hispanica in both carbon-settlement and air pollutant-cleanup in the year 2006 was 692153.70 yuan, its ecology benefit in the year 2016 will be 1111617.73 yuan, its ecology benefit in the year 2026 will be 1285237.26 yuan, its ecology benefit in the year 2036 will be 1414980.33 yuan, its ecology benefit in the year 2046 will be 1510052.66 yuan, its ecology benefit in the year 2056 will be 1574917.78 yuan.