Influence Of Urban Green Space Plant Community Structure On Carbon Storage And Optimization Strategies

In a highly densely populated urban environment,urban green space plant communities are mostly artificial plant communities and maintain specific landscape characteristics under human interference,and the construction of a scientific and reasonable plant community structure is the basis for sustainable development of urban green space.As the basic unit of urban green space,plant community plays an active role in reducing atmospheric CO2 concentration and mitigating climate change,and its spatial structure is closely related to the community carbon storage function.This paper takes Zhengzhou Green Expo Park as the research area,explores the correlation between plant community structure and total annual carbon storage of plant communities,compares and analyzes the differences in carbon storage of plant communities with different structures,establishes a statistical relationship model between plant community structure factors and total annual carbon storage of plant communities,selects planting density and vegetation cover as the key structural factors for optimizing carbon storage of plant communities,and aims to improve the carbon storage of urban green space.To improve the carbon storage of urban green space,we propose a strategy for optimizing plant community structure,and provide data support for the construction of reasonable plant communities.A field survey of 106 plant communities(20 × 20 m)in the study area was conducted to investigate mainly tree species and maintenance management information within the plant communities.The Libackpack,Lcpro T portable photosynthesizer,and CI-110 canopy analyzer were used to collect information on plant community structure,including tree height,diameter at breast height,canopy area,leaf area index,and photosynthetic rate.Based on photosynthetic rate method,biomass method,oxidation method and equivalent coefficient method,vegetation carbon storage,soil carbon storage and conservation management carbon emission of plant communities were quantified.MATLAB software was used to analyze the correlation between plant community structure and annual carbon storage of plant communities,and to establish a nonlinear regression equation and statistical relationship model between them.The study showed that(1)plant community structure had a significant effect on plant community carbon storage.Planting density was significantly and positively correlated with vegetation carbon storage,soil carbon storage and conservation carbon emissions(p<0.05);vegetation cover was significantly and positively correlated with vegetation carbon storage and soil carbon storage(p<0.05);and average tree height was significantly and positively correlated with conservation carbon emissions only(p<0.05).The remaining three plant community structure factors(angular scale,canopy competition height,and community height difference)were not correlated(p>0.05)with the four carbon storage characteristics(biomass,foliage,soil,and conservation).(2)Plant community carbon storage increased fastest from 183.04 kg CO2-eq/y-1 to 327.67 kg CO2-eq/y-1 at planting density and vegetation cover structural factors of 0.1 to 0.15 and 0.5 to 1,respectively,with an increase of up to 44%,and then stopped increasing significantly.Plant community carbon storage was optimal at planting density and vegetation cover of 0.15 and 1,at 327.67 kg CO2-eq/y-1.Leaf carbon storage was the main source of plant community carbon storage,compared to about 10.12 times of biomass carbon storage and 18.93 times of soil carbon storage.Comparing the growth rate of plant community carbon storage,the growth rate of planting density carbon storage was greater than vegetation cover in a specific interval(0-0.15).Conservation carbon emissions were influenced by planting density,increasing with planting density and decreasing with vegetation cover.(3)Plant communities can improve community carbon storage by adjusting planting density and vegetation cover,and the degree of influence of plant community structural factors planting density and vegetation cover on plant community carbon storage is as high as 43%.Planting density has the greatest influence on plant community carbon storage,which is 27.24 times higher than vegetation cover,and is a key structural factor for optimizing plant community carbon storage.This study provides data reference for carbon management and low carbon development of urban green space,design scheme reference for landscape green space design units,and has positive significance for vegetation in reducing atmospheric carbon content and slowing down the current climate warming.