Research On Ecological Effects Of Green Space In Residential Area Of Red Valley Beach Newly Developed Area In Nanchang

With the development of city economy,the increase of urban population and the continuous expansion of urban scale,the urban environment has been greatly threatened and challenged.Rapid urbanization makes the original natural underlying surface is replaced by hard brick,the underlying nature of the change,exacerbated the city’s small climate change,making urban heat island effect,urban waterlogging,haze pollution and a series of environmental problems frequent,not only hindered the urban economic development,but also affect people’s health.At present,some studies have shown that the increase of green area in residential area is one of the effective methods to improve the urban environmental.The residential area has important ecological regulation function in the areas of cooling and humidification,carbon sequestration,oxygenation,flood control and dust removal.The traditional green space research index,mostly two-dimensional,in order to make up for the lack of two-dimensional green indicators,the emergence of tridimensional green biomass as the representative of the three-dimensional green index.The study of tridimensional green biomass,more concentrated in the calculation,the existing research is mostly based on the large scale of the city,and less research on the small scale of the residential area.This paper uses plant geography,landscape ecology theory,and systematically studies the green space of red valley beach newly developed area in Nanchang.Combining with field investigation,the vegetation types,greenbelt types and community structure in the plot,and selected ten 20m×20m samples according to the vegetation of each plot,and there were no green vegetation cover contrast sample one.In August 2016 to September 2016,December 2016 to January 2017,respectively,measured the three residential area of vegetation cooling,humidification,reduction PM_2.5 and the ability of dust retention,to explore the relationship between urban green space and ecological benefits.The results are as follows:（1）Measurement of arbor,shrubs under the crown high,crown width,according to the shape of the crown using the model formula,we can quickly calculate the single tree,shrub green three-dimensional.In the three plot selected samples,the arbor accounted for the total green three-dimensional volume of the main body,and the proportion of shrubs and herbs is very small,indicating that the tridimensional green biomass is mainly determined by the arbor layer.（2）The study found that the degree of temperature reduction and the degree of humidification were significantly correlated with the tridimensional green biomass in the sample.Logistic curve was used to fit the nonlinearity.The correlation coefficient Adj.R2 was about 0.90,and the fitting effect was good.Tridimensional green biomass critical value of 1000 m3 in the upper and lower,the plant temperature and humidity to achieve the basic effect,cooling and wetting tends to be stable.（3）The study found that t the PM_2.5 and PM₁₀ concentrations in the air were more obvious than those in the three-dimensional green plants,but the PM_2.5 and PM₁₀ in the air were not significantly different in the small area.The correlation of different types of green space on the PM_2.5 absorption capacity,from strong to weak respectively is shrubs-herbs-arbor>shrubs-herbs>herbs,in outside,the higher the concentration of PM_2.5,shrubs-herbs-arbor absorption effect is more obvious,the tall trees affected by turbulence and its transpiration effect on PM_2.5,PM₁₀ has better absorption effect.（4）Among the main greening vegetation in the residential area,prunus cerasifera,osmanthus and viburnum awabuki are the plants with better dust retention,magnolia grandiflora,camellia japonica and myrica rubra belongs to plants with relatively weak dust tolerance.And found that the strength of vegetation dust retention,not only with the leaf angle,leaf surface roughness and other plant growth characteristics,but also with the distance from the source of pollution,community vegetation conservation and other external environmental factors have a great relationship.