Evaluation Of Urban Forest Ecological Security In Zhengzhou

With the drastic increasing of urbanization.Urban Ecological System is suffering from more and more pressure now.Urban forest ecosystem is becoming the research hotpots.This article is mainly aimed at Zhengzhou city which is with special city form and climatic conditions.Based on the relevant knowledge Ecological security of landscape layout of Zhengzhou forest.Researching the change of urban forest land type from 2003 to 2017 and exploring the value of urban forest ecological serve in Zhengzhou.According to the urban relate indexes in Zhengzhou we developed a pressure-state-respond model(PSR)discussing the safety evaluating it by the Fuzzy evaluation.The main conclusions are as follows:(1)Among the urban forest landscape type of Zhengzhou are mainly consist of Agricultural production forestland,dominant landscapes elements in Zhengzhou have a decisive effect to the whole urban forest Ecosystem of Zhengzhou city.Agricultural production Forestland mainly gathers the outskirts of Zhengzhou city.Traffic woodland and Ancillary forestland average plate area is smaller,they mainly located in the urban build-up area which also have high levels of landscapes fragmentation.According to the changing situation of Zhengzhou’s urban forest form 2003 to 2017,Agricultural production forestland kept decreasing while the building area spreads quickly to the outside of the city.The number of plaques are obviously increased,the average plaque decreased,the landscape degree of crushing also increased.The Forest shape index increasing year by year.This indicates the forest plaque of Zhengzhou is more and more deviating from the standard shape.The edge effect of plaque is getting weaker and weaker.There is not utilize the biological diversity to exchange material wit urban forest ecosystems.(2)The humiture and PM 2.5,PM 10 concentration in urban patches of different structures in Zhengzhou were measured in this article.The results of the research showed that the larger the coverage of urban forest patches were the more obvious of reducing the concentration,the city forest carbon fixation and oxygen release air purification-capacity,temperature and humidity regulation 3 total of 9 ecosystem services assessment index,the results shows that the function of value contribution to environmental purification ability of carbon fixation and oxygen release greater than temperature and humidity regulation ability.(3)Through a large number of data consultation and expert’s consultations,the evaluation set of urban forest ecological security evaluation is set up as five safety levels “unsafe,unhealthy sub-health,safe health “By the fuzzy comprehensive evaluation method is applied Calculate again in a basis of evaluation,can be obtained in Zhengzhou city is the five component vector forest safety evaluation were 0.2846,0.1087,0.1093,0.2774,0.2201,respectively,Zhengzhou city forest ecological security evaluation belongs to the level of "unsafe" probability is 28.46%,belongs to the class of "unhealthy" the probability is 10.87%,the probability of belonging to the class of "sub health" is 10.93%,the probability of belonging to the "safe" level is 27.74%,the probability of belonging to the level of the "health" of 22.01%.According to the principle of maximum membership degree,it is inferred that the result of urban forest ecological safety assessment in Zhengzhou is "unsafe".