Assessment Of Function And Valuation About The Ecosystem Services Provided By Urban Forest In Xiamen

Urban forest is an important part of urban ecosystem, which have the functions of regulating micro-climate, improving the environment, fixing carbon and releasing oxygen, water conservation, increasing the value of real estate and so on. Urban forest plays an important role in the sustainable development of urban systems, thus increasing the urban forest ecosystem services is to achieve urban sustainable development. To carry out urban forest ecosystem services and valuation will provide a theoretical basis for urban ecological construction, and provide the scientific basis for establishing the status of urban forest and improving public awareness.Basing on the analysis of assessment research of the value about the ecosystem services provided by urban forest at home and abroad and present situation, Xiamen urban forest ecosystem services is divided into seven types in this paper. According to the data obatained from Xiamen field survey, collection of materials, questionnaire survey, and indoor sample analyses, this paper estimates the value and function of ecosystem service provided by urban forest in Xiamen, applicating landscape ecology, urban ecology and other principles. The ecosystem function of production, carbon sequestration, cooling, air purification, water conversation, recreational, society of urban forest in Xiamen are evaluated by using the methods of market price, and shadow price method. Through analyzing the study findings, the results were as followed:(1)Carbon sequestration function: The results show that in the clean environment:①high-carbon group, including Hinidvud tiliaceus, Erythrina crista-galli, Nerium oleander;②middle-carbon group, including Ficus laco, Ficus conicnna, Erythrina orientalis, Bauhinia blackeana, Pterocarpus indicus, Mangifera indica, Alstonia scholaris;③low-carbon group, including Ficus altissima.In the dirty environment:①high-carbon group, Nerium oleander, Erythrina crista-galli;②middle-carbon group, including Hinidvud tiliaceus, Alstonia scholaris, Bauhinia blackeana;③low-carbon group, including Mangifera indica, Erythrina orientalis, Pterocarpus indicus, Ficus laco, Ficus conicnna, Ficus altissima.Both in the clean and dirty environment, Nerium oleander and Erythrina crista-galli all have high carbon content, however, Ficus altissima has the lowest carbon content in the two environments. Most plant in the polluted environment represent lower carbon than in the clean environment. Selection of tree species in urban forests can refer to the carbon sequestration function of tree.(2) The function of temprature drop and increased humidity: the temprature drop and increased humidity of different urban forests are various. Cooling effect is park> residential area> roads, the value of them were 1.93℃, 1.40℃and 0.68℃respectively; increasing humidity effect is residential> park> roads, the value of them are 9.54%, 3.70% and 2.50% respectively. In Bailuzhou Park in the summer the temprature drop and increased humidity of plant communities are both arbor-shrub-herb >water body > arbor-shrub> shrub-herb> herb; The range of them were separately 0.6~2.8℃and 2.2~5.6%.Compared with the clean environment, most plants are in the polluted environment showed greater daily transpiration per unit area .(3) Atmospheric Pollutants: grading the plant into three levers by the sulfur absorption intensity : high (> 0.800 g/ kg), including Terminalia mantaly, Nerium oleander; medium (0.300 ~ 0.800 g/kg), including Erythrina orientalis, Ficus laco, Ficus conicnna; weak (<0.300 g/kg), including Erythrina crista-galli, Ficus altissima, Pterocarpus indicus, Bauhinia blackeana. The highest of them is Terminalia mantaly, Nerium oleander and Erythrina orientalis take the second, then the lowest is Bauhinia blackeana.The range of cleaning dust percentage of every observation point is 9.55 ~ 30.56%, the mean dust purification percentage is roads > residential area > park, and are respectively 19.85%, 15.88%, 9.84%. Dust cleaning rate may be used to represent that the urban forest has a certain purify ability, but it can't be used to express the strength of cleaning dust function provided by urban forest.The concentration of air anion is the park> residential area> roads, the average value are 702 lons/cm~3, 577 lons/cm~3, 525 lons/cm~3 individully. The concentration of air anion of plant communities at different observation point were significantly different. Most of measurement points air anion of plant communities are showed summer> autumn> spring> winter.The noise reduction effect of single tree structure is the worest, and the value of it is 0.01~0.03dB.however, the best is the arbor-shrub-herb multilayer structures. Noise reduction value of arbor + shrub + hedge, arbor + shrub, arbor + arbor + arbor, arbor + arbor, arbor + grass is 1.50 ~ 3.20 dB, 1.20 ~ 1.52 dB, 0.65 ~ 2.61 dB, 0.21 ~ 1.03 dB, 0.26 ~ 0.40 dB separately.(4)Assessment of valuation about the ecosystem services provided by urban forest:the total value of urban forest ecosystem Services is 1.91 billon yuan /a in Xiamen in 2009, accounting for 1.18% of gross national economy, which shows the necessity to improve the ecological service function beacaues of the weak holding capacity to the environment. Among them, the value of production function, carbon fixation and released oxygen, temperature drop, atmosphere purification, water conservation, recreational features, society function are individually 7348.5 million yuan /a, 11769.93 million yuan /a, 3028.20 million yuan / a, 39446.66 million yuan/a, 51200 million yuan /a, 69295.73 million yuan /a, 9314.27 million yuan /a. Water conservation features, society function, air purification function of the contribution rate is relatively large, which separately are 36.20%, 26.75%, 20.61%, three functions integrated account for 83.56% of the total value.