Study On The Environmental Impact Of Urban Greenspace Maintenance Influenced By Plant Structures Based On The LCA Method

The urban greenspace needs continuing maintenance work,and the major environmental impact caused by the maintenance is energy consumption and green house gas(GHG)emission.However,the continuing increase of the urban greenspace is a key factor in the development of the modern Chinese city.The aim of this research is the environmental influence of the plant structure combinations and maintenance strength.The research objectives are: Find the variation tendencies of the energy consumption and GHG emission as the changes of the combinations of woodland,shrubs,herbaceous and grassland in the urban greenspace;Summarized the major environmental influenced maintenance task through the characteristic calculation;Divided the greenspace combined by different plant structures into 4 phases of the environmental impact level.This essay talked the quantitative procedure of the urban greenspace maintenance environmental impacts followed the LCA method.The goal and scope is continuing to provide the greenspace landscape site can satisfy the original design object;The life cycle range of the greenspace maintenance is a single maintenance year;After that,we were collecting the basic maintenance data in 93 sample plots(20m×20m)of the 12 research areas in the city Zheng Zhou,and quantitated the environmental impact characteristic values by plant layers in each sample plot.In result,the tree density of woodland and the area combination of shrubs/herbaceous/grassland owned the general correlations with the maintenance workload in each plant layer.In different ages of the greenspace,the curves of the maintenance energy consumption and GHG emission through the increase of plant density in the woodland layer were in the parabola shape,and the curves through the increase of the area combinations in the shrubs/herbaceous/grassland were in the rising tendency.The environmental impact changing character followed the changing of the maintenance stage in every greenspace unit by plant layer: The curves in woody plant layer is in gently increase form the Yong stage to the Mid-age stage,and then dramatically decrease until to the Mature stage;The curves in herbaceous plant layer is in slightly dropping from the Yong stage to the Mature stage.In conclusion,the fertilization work is the major contributor to the greenspace maintenance environmental impact,occupied the 50% of the total environmental impact characteristic values.During the separate looking of every plant layer,we found that while restricting the full stage maintenance environmental impact under the middle strength level,the structure combination restricts condition in every plant layer from tight to loose: grassland>shurbs>herbaced>woodland.During the comprehensive looking of the plant community combination by layers,we found that while restricting the full stage maintenance environmental impact under the middle strength level in sample plot size plant community(400m2,the energy consumption under 233000 MJ and the GHG emission under 2690kg/CO2-e),the structure restrict position in each layer is: Woodland density(?0.35)and herbaceous area proportion(?1)in arbitrary proportion;Shurs and grassland area proportion under 0.35 and 0.55 in respectively.In summary of the research in above,this paper can have three directions of application in the future research: Apply the cost accounting reference for the urban greenspace maintenance department;Apply the low energy and waste saving policy reference for the urban managing department;Apply the low environmental impact greenspace design reference for the landscape design department.The quantitative maintenance environmental impact data summarized in this paper can help with the sustainable development of the greenspace.