| Urban industrial zone is the main source for affecting urban environmental conditions by its large CO2let. Greenhouse gas in industrial zones is mainly from steel industry whose gas let ranking the3rd is next to electric departments and construction departments. Baosteel located in Shanghai urban industrial zone as a national leading state owned steel enterprise, a typical representative who should first take the responsibility to reduce carbon emission. How Baosteel deal with the effect due to large carbon let, and how to take the responsibility of carbon emission reduction will greatly contribute to Shanghai’s carbon emission reduction and make a good example for other steel enterprises in China. It is of great cost to reduce the carbon emission by reducing energy source use and industrial productions or by improving technologies et., which is to impede the economy development, but it will be of low cost to increase the CO2absorption by ecological environmental measures such as forestation and reforestation.It is worldly acknowledged that utilizing plant carbon fixation ability to reduce CO2was the most economic way, and vegetation carbon storage and carbon fixation ability have been the study hotspots by recent years. Current greening construction in Baosteel factory area is mainly for antifouling. Plant carbon fixation ability has been more and more focused as well as improving the environment and adjusting the atmosphere in the purpose to deal with global atmosphere change by low carbon society for urban development. To select greening trees of high carbon fixation ability and optimize vegetation communities, such to improve the vegetation carbon storage and carbon fixation ability absorbing and fixing more CO2is quite important.Shanghai Baosteel, a famous industrial zone was chose as a case study. Vegetation carbon storage and carbon fixation ability in Baosteel was estimated based on the vegetation investigation, aero-photograph digitalization, measurement of the biomass of dominant species and the model. Carbon fixation efficiency was evaluated using the carbon tax law. These studies were carried out to provide more scientific and perfect basis for the configuration of city green-land plant community in industrial zones and tree species selection, also for the analysis of enterprise greening construction cost efficiency. Main results showed that:(1) Vegetation in Baosteel factory areaBaosteel factory area covered688.60hm2in2010, of which439.14hm2was evergreen vegetation with the cover ratio of63.77%while249.46hm2was deciduous vegetation with the cover ratio of36.23%. Evergreen vegetation’s area was far larger than deciduous vegetation’s in all regions.Main vegetation of factory area could be classified into9types by life-forms, namely evergreen conifer forests, conifer-broadleaved mixed forests, evergreen broadleaved forests, deciduous broadleaved forests, evergreen-deciduous broadleaved mixed forests, evergreen shrubs, deciduous shrubs and herbs. Evergreen conifer forests and deciduous conifer forests were dominated mainly by Cedrus deodara community and Metasequoia glyptostroboides community; evergreen broadleaved forests could be classified into Cinnamonmum camphora community and Ligustrum lucidum community, deciduous broadleaved forests were dominated by Populus euramevicana community and deciduous conifer forests by M. glyptostroboides community; shrubs were dominated by evergreen Nerium indicum community, Viburnum awabuki community,Distylium racemosum community; herbs were dominated by Ophiopogon japonicus community and Cynodon dactylon community. C. camphora was the most frequent species, and evergreen broadleaved trees C. camphora, L. lucidum and deciduous broadleaved trees P. euramevicana and deciduous conifer tree M. glyptostroboides distributed the widest forming the major part of the vegetation in factory area. Greening in factory area was mainly of evergreen species and relatively fewer of deciduous ones. Most communities in factory area were of tree-shrub-herb multi-layers and few were of simple configuration.(2) Pattern of vegetation carbon storage, carbon density and carbon fixation ability in Baosteel factory areaTotal vegetation carbon storage in Baosteel was38020～45560t, average carbon density was45.82～53.27t·hm-2, and carbon fixation ability was5.91～6.87t·hm-2·a-1]. Under the same community type, carbon storage, carbon density and carbon fixation ability of tree-shrub-herb community were higher than those of other community structure. Carbon storage, carbon density and carbon fixation ability of mixed forest were higher than those of pure forest in road greening belts under the same conditions.Vegetation area change in all regions was well positively correlated with carbon storage change, namely carbon storage increased with vegetation area’s increase. Average carbon density in Baosteel factory area was45.82～53.27t·hm-2, lower than the national average, while average carbon density and carbon fixation ability in A and D were higher than the averages of Shanghai urban forests.Pattern of carbon density distribution was D>A>C>B. Carbon density and carbon fixation ability were influenced by the plant growth status, and were well positively correlated with region cleanness, namely carbon density and carbon fixation ability increased with region cleanness.(3) Vegetation carbon fixation potential and economic efficiency in Baosteel factory areaVegetation carbon storage increment in Baosteel was about3992.99～4736.17t a year, and was estimated by19964.96～23680.84t and39929.93～47361.68t for the next5and10years. Vegetation carbon storage was estimated by57981.65～69236.28t and77946.61～92917.12t in the year of2015and2020respectively.Vegetation carbon storage economic efficiency was about13507.33～16185.85ten-thousand RMB, and economic efficiency of vegetation carbon storage increment was about1418.71～1682.76ten-thousand RMB, and would be7093.55～8413.80ten-thousand RMB and14187.10～16827.61ten-thousand RMB for the next5and10years. Economic efficiency of vegetation carbon storage was estimated by20600.88～24599.65ten-thousand RMB and27694.43～33013.45ten-thousand RMB in the year of2015and2020respectively, which created good economic efficiency for Baosteel. Vegetation in Baosteel factory area played an active part in carbon fixation and carbon emission reduction and increased its carbon emission space in international market of carbon sink. (4)Improvement of vegetation carbon storage and carbon fixation ability in Baosteel factory areaWith limited space for greening in Baosteel factory area, greening planning and distribution optimizing should be considered in future greening construction which is to develop solid greening, to increase the greening capability making up for plane greening so as to further increase the vegetation carbon storage in factory area. In order to reconstruct low-efficiency community, trees, shrubs, herbs, lianas and multi-trees were adopted to create multi-layer mixed forests to construct stable ecological plant communities which could make the best of spatial resources, increase community density and crown density, increase the carbon absorption, and keep a rather high carbon fixation ability by increasing biomass and carbon density of unit area. Plants strong in carbon fixation as well as in antifouling should be considered to optimize the community composition, so as to build antifouling and carbon fixation community. |
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