Beijing Urban Green Space System Function Evaluation And Development Strategy

As the basic carrier of urban ecosystem, urban green space plays an irreplaceable role in urban ecosystem, especially for its eco-efficiency and integrated functions. With the accelerating urbanization, the decrease of available urban land leads to urges on the solutions for how to play the comprehensive functions of UGS by a more optimized spatial arrangement and constitution and realize urban sustainable development by coordinating the relationship between urban development and environment construction on the limited land resources in the city.The highlighted issues of urban green space system currently such as the structure is incomplete, the system is imperfect, the distribution is uneven and the heat island effect is prominent etc. require to be studied and analyzed to promote its function on ecology, landscaping, leisure, culture, disaster prevention etc.. The current research takes urban green space of Beijing as the object by using the methods of remote sensing, GIS ect. under the theory of landscape ecology and the characteristic of the UGS to analyze the landscape pattern, green space system and the function, study the relationship between heat island effect and vegetation coverage, and evaluate the landscape plant resources in Beijing to provide a scientific basis for the ecological projects and construction of green landscape in Beijing. The key results of study are as follows. 1. Analyse on pattern of Beijing urban green landscapeTaking Beijing urban green space as the study object with two remote sensing images in 2008 and 2009 as the main data sources, we analyze the changes in landscape pattern of urban and public green space. The results show that (1) the basal framework of green space is achieved when the structure is still incomplete, the system is imperfect, the distribution is uneven; (2) urbanization process is accelerating when the schemed green space is unequally developed. 2. The relationship between urban heat island and urban vegetation coverage in BeijingThe data from satellite remote sensing data by Landsat in 1987,2000 and 2007' showed the spatial evolvement of urban heat island patterns in Beijing. (1) DN and vegetation coverage have a strongly negative correlation; (2) the expand of the city extent is the most direct reason for expansion of urban heat island; (3) the temperature of urban district is higher than suburban district, apparent "urban heat island" phenomenon has appeared in Beijing; (4) the scope of urban heat island is expanding, the distribution is much more fragmented.3. Comprehensive quantitative evaluation of green space system structure and function in ancient districts of BeijingTaking Beijing ancient districts as the research object, the green space system construction progress is evaluated quantitatively. (1) A uniform guideline to evaluate the structures and functions of urban green space system is achieved. (2) Using the methods of The Analgtic Hierarachy Process (AHP), we find that the green space is the most important one among the 8 factors affecting urban green space structure and function with a 22.7% proportion while Landscape Fragmentation and shadow zone play the second role taking the proportion of 16.2% and 10.6% respectively. (3) Results through the current guideline shows that Chongwen district possesses a better green space structure and function while those of Xuanwu district need to be improved.4. Status of plants application in urban landscape in BeijingFrom green census data of Beijing in 2010 we make the statistical analysis and research on urban application of landscape plant, including plant species composition, source, application frequency, quantity and different plants used in gardens and ancient trees status. The points are as follows:(1) the diversity of Garden plants is rich when however few plants is in a large scale; (2) the proportion of native species is rather low and an increasing application is reasonable; (3) tree, shrub and grass are imbalanced and the arrangement diversity is poor; (4) selection of garden plants need more scientific guidance; (5) storage of garden plants is insufficient and irrational; (6) protection and rejuvenation of ancient trees should be strengthened.5. The development strategy of urban green space system in BeijingSeveral points for development strategies of Beijing urban green space are summarized based on the previous researchs and results as the following:(1) Urban green space can be excavated through using various virescence methods and technologies to promote the use of green area more efficiently. (2) a reasonable structure of green space system should be built in order to prevent urban heat island spread. (3) Updating the criteria, defining the index and accomplish of urban green space evaluation system, management rules and regulations laws are indispensable. (4) selection and application of garden plants in urban green space should be more reasonable while management and conservation work of urban green space should be strenghened; (5) the function of urban green system should be improved toward a multifunctional future.