Difference Analysis Of The Influence Factors For Trees And Shrubs? Carbon Storage In Shanghai,China?s Urban And Peri-urban

Studies have documented the biophysical correlates of urban forest carbon storage and increasingly urban forests are promoted as a strategy for low-carbon cities.While urbanization affects both the structure and function of urban forest ecosystems,quantitative analyses of specific drivers or causal factors of carbon stores in subtropical urban versus peri-urban forests are scarce.We used field data from random plots across an urban to rural gradient in Shanghai,China,region-specific biomass equations,and structural equation modeling of commonly studied urban forest ecological and socioeconomic drivers(Percent tree and shrub cover,Tree and shrub density,Tree and shrub species diversity and UI,The density of population in urban,Landuse,Distance from the people's Square)to analyze their effects on above ground tree carbon stores.The main conclusions of this paper are as the following:(1)Based on the multiple linear regression analysis,urban and suburban were defined,the results showed that:urban and peri-urban showed spatial differentiation.This kind of spatial differentiation,the history of development in Shanghai and functions of each regions is consistent,which can provide a scientific basis for urban planning and management.(2)Our plot based sampling found trees and shrubs from 90 species belonging to74 genera and 50 families in the study transect.The number of species,the importance value of species,the growth form of species,tree and shrub species diversity,percent tree and shrub cover and The number of tree and shrub individuals per hectare in urban and suburban regions have significant differences.The composition and structure of species in urban and suburban showed some differences,the total number of species in urban is more than in suburban.The tree and shrub species similarity of10 with the highest importance values in Shanghai's urban and peri-urban forests are basically flat.Cinnamomum camphora has an absolute advantage in urban,and suburban regions.The proportion of evergreen and deciduous life form is almost equal in urban and suburban regions.Four species diversity indexes Richness(S),Evenness(E),Simpson(D)and Shannon-Wiener(H)trends in each region are urban>suburban,which shows that the differences of species diversity is result of human activities.The average the number of tree and shrub individuals per hectare in peri-urban forests was greater in urban forests.While percent tree and shrub cover were greater in urban forests.(3)We used structural equation modeling of commonly studied urban forest ecological and socioeconomic drivers to analyze their effects on above ground tree carbon stores.Results show that in both urban and peri-urban forests,ecological drivers had more significant and positive effect on tree and shrub carbon than socioeconomic drivers.While,percent tree and shrub cover had an even greater effect(P<0.01).Further,tree and shrub density,tree and shrub species diversity,UI and the density of population in urban had no effects on carbon stores(P > 0.05).Peri-urban forests also exhibited a significant effect of landuse on carbon stores,that was however not significant in urban forests.Distance from the people's Square had both direct and indirect effects on tree and shrub carbon,with the indirect effect via percent tree and shrub cover in urban forests.While distance from the people's Square did not significantly influence carbon stores in peri-urban forests.